Transcript for:
Overview of Scleral Lenses

[Music] good morning everyone and thank you for joining me today as we discuss the basics of scleral lenses my name is Ania gloomier II and I'm an assistant professor at the New England College of Optometry as well as an attending optometrist at one of the college's owned and operated clinics called the New England College of Optometry center for eye care I work at their contact lens department and then I also spend some time at Boston Medical Center in the contact lens department as well so without further ado let's get started on scleral lens assessment and fitting so as a general basic intro to sclera lenses as many of you may already know sclera lenses have made a comeback over the last decade and before this time only a handful of practitioners were fitting sclera lenses and not many commercial sclera lenses were being manufactured fast forward to today in the United States we have countless Clairol lenses at our disposal and each with their own unique design and features so the first Clairol lens was discovered in 1988 and it was made out of blown glass interestingly it was still at that time being utilized for conditions such as keratoconus and even to correct high refractive errors even back in 1988 after that period sclera lenses sort of lost momentum as glass was a poor oxygen permeable material and they were reintroduced with the introduction of PMMA plastic material now the PMMA plastic material was less fragile than glass and but it was more accurately able to allow for a more optimal fit so that was the advantage of having PMMA on board but once again PMMA as well did not provide enough oxygen permeability to stick around and then as corneal rigid gas permeable lenses were introduced followed by soft contact lenses made their way into the industry scleral lens research and development sort of came to a halt for the time being however sclera lenses have made a full comeback probably stronger more now than ever before and we as scleral lens fitting practitioners have many different options at this time and day for even the most challenging fits challenging eyes and to me one of the most rewarding aspects of scleral lenses is the ability to postpone or even prevent surgery prevent corneal surgery that is alright so just to get an idea of who I'm speaking with today I'd like to know how familiar you are with sclera lenses so this is our first poll question so how familiar are you with sclera lenses a iFit sclera lenses in my practice all the time be I have photos clear lens in my practice before but do so rarely see I have not yet fit as clarence in my practice but have hit them on colleagues or attended scleral lens workshops andy what what is is Clarence I'll give you guys some time to answer that okay great so I see that we have some participants that have fit is Clara lens before that's great and then we have some that you know kind of know a little bit about it but maybe not much and then some that you know want to know what a sclera lenses so that brings me right to my next question next slide here so what exactly is a scleral lens so just as a review for those of you that do you know what is Claira lenses these are rigid gas permeable lens materials of large diameter and they're designed to vault over the entire cornea and land peacefully on the sclera and in its most true definition a scleral contact lens contacts the sclera and there's absolutely no contact with the cornea now this allows the lens to vault over or clear over any irregularity or diseased ocular surface this lens holds a liquid reservoir of non preserved saline so that the cornea in this fluid when the lens is worn with some but a very limited to your exchange so just to you know compare sclera lenses to corneal gas permeable lenses many of you may be more familiar with corneal gas permeable lenses and I still fit a lot of these in my practice today without going into too much detail about corneal GPS you know they have a list of advantages of their own but by definition corneal GPS rest completely on the cornea they're typically smaller than ten millimeters they're designed to move on the cornea to allow for ample tear exchange and since the cornea is an extremely sensitive tissue with lots and lots of nerve plexus there is more lens awareness with a small diameter GP in contrast sclera lenses rest on the conjunctiva which is far less sensitive there's also limited movement with sclera lenses so there's less lid interaction and thus less lens awareness and it may seem counterintuitive because of the very large size of the scleral lens but it's surprisingly very comfortable because there is no contact with the cornea another point to note compared to corneal gps a scleral lens tends to be a lot more stable on the eye my patients that have trouble with retaining the lens and their eye you know whether it be dislodging the lens or the lens decentering I typically switch these patients into a scleral lens and a lot of them report improved success with these types of lenses so in summary I would say sclera lenses provide similar if not improved visual potential but more stability and more patient comfort as well so the sclera Society introduced an internationally-recognized nomenclature for describing sclera lenses based on the resting zone of the lens and not lens diameter so it was previously categorised sclera lenses were previously categorized on by the lens diameter the new nomenclature is basically characterized by where the lens lands so if the if the lens lands on the cornea it is it is deemed a corneal lens if it lands entirely on the sclera it's called a scleral lens and if it lands somewhere in between it's called a corneal scleral lens so sounds easy enough now the reason behind the change in nomenclature is based on the relationship between different sized corneas and lens diameters for example in someone with a micro cornea that relationship with a 10 millimeter lens would be very different than that of a normal cornea that's about 12 millimeter cornea so when there's full sclera landing the lens definition can be further broken down into a mini sclera and large rural design if less than six millimeters larger than HIV ID then it's classified as a mini scleral versus a large scleral if there's more than six millimeters of hpid sorry if the lens is larger than six millimeters of the hpid of the patient now these distinctions serve to emphasize an important point on corneal clearance so larger lenses have a bigger sagittal depth and therefore more corneal clearance so greater to your reservoir under the lens compared to a mini scleral lens which will allow some apical clearance now other factors that may contribute to lens selection are anatomical barriers a patient with a small palpebral aperture may do better with a smaller lens diameter and if a patient has pinguicula the the decision to go smaller to avoid the penguia kula or larger to vault over the penguin penguin Coola and then all those glitter lens designs may differ excuse me from manufacturer to manufacturer the basic scleral lens design is the same and I just want to go over that with you guys real quick here a basic symmetrical scleral lens can be broken down into three distinct zones the first is the optic zone which houses in the base curb and power sophisticated optical designs can allow us to add front toric front surface tourists City to correct for any residual astigmatism and also to add multifocal optics on the front surface of the lens as well now this zone to an extent can also aid in controlling the amount of central corneal clearance and overall sagittal depth steepening this zone can serve to increase sagittal depth while flattening can serve to reduce sagittal depth the transitional intermediate zone is the point from the lens and I'm just going to use my marker here so this is our optic Zone here and then we have our transitional zone here demarcated in this little red so the transitional intermediate zone is a point from the edge of the optical zone to the scleral lens landing zone or the haptic zone this zone has a lot more impact on the sagittal depth and what I mean by sagittal depth is this area here okay so technically our sagittal depth is all the way from of the lens is all the way from here to here but since the lens is landing on the sclera and you know vaulting over the cornea here I'm just going to kind of tell you guys that the the depths including the corneal depth it can extend from here all the way to here so that transitional zone has a lot more control over the sagittal depth so manipulating that can manipulate the amount of liquid reservoir we have underneath the scleral lens in most lens designs these changes can also be performed independently of the optical zone or the haptic zone so if you really only wanted to change the sagittal depth of the lens that can be established with just manipulating the transitional zone but maintaining the same optic zone or in the same haptic zone this zone can also be designed in a reverse geometry profile and this is important for patients that are post refractive surgery post LASIK or post penetrating keratoplasty the haptic zone or the sclera landing zone is the area where the lens makes contact with the ocular surface of this zone right here where it lands right on the sclera okay the goal here is to distribute the weight of the lens evenly over the entire landing zone so as to limit any pressure and to align with underlying conjunctiva as closely as possible without bearing into the conjunctiva in terms of sclera lenses a back a back toric lens design i'm just gonna quickly touch on this refers to the peripheral edges being steeper or flatter as compared to their opposite meridians and we're beginning to learn a lot more about the shape of the sclera just because of the invent and I guess the resurgence of sclera lenses we're starting to study what the scleral topography is like more now than ever before so you know a sides corneal topography now we're delving into what the scleral topography is to aid us in fitting Clairol lenses a lot more accurately so more often than not the anterior ocular surface is actually asymmetrical in shape and we know that the sclera shape in most eyes steepest temporally and flattest nasally and that this is suspected to be related to the ocular extra ocular muscle insertion in that the medial rectus is the most anterior so it contributes to the lens sitting a certain way in most design cases so one of the other important discoveries over the last decade has been that the scleral twisted increases the further away we move from the limbus so beyond 16 millimeters we're likely to see a lot more toric peripheries then when we're closer or smaller closer to the limbus okay now this is there's also very I also want to add that there's also very little correlation between the corneal and scleral tricity so just because a patient has an exorbitant amount of corneal tricity that doesn't necessarily mean that the scleral atrocity is also going to be high and vice versa all right moving on to just talking a little bit more about the toric periphery so total peripheral curve landing zone design serves to better match the natural toric nature of the sclera as we were just talking about this serves to meet our goal of evenly distributing the scleral lens so that there are fewer areas of localized pressure and that and LED less lens edge lift it also helps us in improving situation and to decrease any air bubbles from getting underneath the lens or any debris from entering under the lens to assess the need for toric peripheral curbs an easy method is to utilize sodium fluorescein so applying on the outer surface of the scleral lens and then just watching as the fluorescein enters the lens chamber if the sodium fluorescein is entering in an asymmetric pattern or more in one meridian than another meridian you might want to utilize a toric peripheral landing zone to better align the sclera to the lens so upon examination if the tear reservoir also looks like a snow globe where you see a lot of debris trapped underneath the lens this is another sign that you know you may need to add some torque peripheral curves as one of the meridians of the sclera landing zone may be flatter allowing debris to enter the lens enter the lens chamber I should say and then you can also use Oct and we will talk a little bit more about OCT in a little bit here you can also use an anterior segment OCT 2 vision scleral lens and identify any areas of asymmetry across the edge profile of a scleral lens so to review and summarize the benefits of a back surfaced toric design include providing even distribution along the lens landing zone so that there's a decreased localized pressure in one aspect of the sclera and we have found that adding a peripheral to our curve also increases patient comfort it reduces debris build up like we spoke about it prevents bubble formation it reduces flexure on the eye it's also beneficial in providing rotational stability which is very important if you're adding front surface toric optics onto the lens because at that point you really want the lens to be stable and stationary and so overcoming all of these challenges can ultimately reduce a lot of valuable chair time as well and you know increase in patient comfort all right scleral lens indications so there is an increasing number of applications lera lens indications beyond just keratoconus which seems to be one of the biggest reasons we're utilizing sclera lenses today the main three main indications that we'll discuss our improvement in vision protection of the ocular surface and providing comfort so these are examples of condition categories related to corneal irregularity in the setting of corneal act Asia or corneal scarring that can be neutralized by the fluid reservoir of the scleral lens and of course more and more practitioners are beginning to fix clear lenses on normal corneas for just plain refractive errors such as high myopia you know regular astigmatism even irregular stigmatism and presbyopia so multifocal optics as well so primary ectasias include conditions such as keratoconus as you can see in this picture up top here pollution marginal degeneration kereta globus and then post surgical and secondary ectasias from status post corneal transplant lasik radial keratotomy RK astigmatic keratotomy and penetrating keratoplasty like in this picture here and then other corneal irregularities include primary corneal scarring scarring from post infection herpes simplex scarring from trauma and then of course refractive error as well sclera lenses can also act as a shield to protect the eye from chronic desiccation as seen in cases of surface exposure neuro trophic disease and mechanical insults such as chook Isis now there have been benefits described for patients with persistent epithelial defects so in this top left picture here we see this patient with lag up Thomas from blepharoplasty that results in exposure carrot keratitis and carrot top a--they um as well as a lot of neo inferior leads top right here also has black op Thomas from an acoustic neuroma that is more severe resulting in colonial haze and neo in this exposed area bottom left here I'm seeing a patient with a persistent epithelial defect on a grafted cornea and then bottom right is a patient with neurotrophic cornea from herpes zoster with the persistent epithelial defect and subsequent thinning so the use of the sclera lenses as a therapeutic management of ocular surface disease was previously covered in one of the cyber state lectures as well so I encourage you to listen to that lecture if you want to delve deeper into understanding this aspect of sclera lenses and lastly providing comfort so sclera lenses can provide comfort by stabilizing the ocular surface in very extreme ocular surface diseases they were to allow for epithelial healing and decrease symptoms of burning stinging light sensitivity and foreign body sensation these extreme conditions include surface conditions such as Sjogren's disease graft-versus-host disease stevens-johnson syndrome and ocular circuit Richard pemphigoid so in this picture here we have a patient with a graft-versus-host disease with a confluent and bilateral corneal staining and filaments as us can see over here and then after about three hours of wearing the pros device which I can go over and a little bit more detail if there's an interest in learning about Boston sight and the pros device so after three hours of wearing the pros device we're starting to see a lot less staining and reduce filaments here and that's only after three hours of wear all right now let's um talk a little bit more about fitting sclera lenses so we're gonna kind of backtrack a little bit and delve down deeper into just the basics of scleral lens fitting so some of the challenges that practitioners might run into is a determination of the clearance value so underneath the scleral lens how much clearance do we really have is it adequate do we need to you know increase it or do we need to decrease it how much should we be expecting all those kinds of questions as many of you can understand fitting can be time-consuming as well there's frequent remakes and that requires frequent wizards from the patients to come in and try on the lenses and then there's you know complications that can arise with the debris under the reservoir surface issues patient comfort issues if there's some lead lens edge awareness some studies have reported on estimate that a new fitting would require about four to six visits and about three and a half lenz remakes per patient another aspect to the challenges is centration so like i spoke about earlier the Teresa T of the sclera sometimes can cause the lens to dissenter typically the lens will D Center down and out so that's another challenge is getting that sclera to scleral lens to fit peacefully and and gracefully on the sclera so it's aligning well one of the first issues is knowing where to start so selecting a good initial lens can save you a lot of time from inserting settling and removing the lens three four or five times per visit so most manufacturers will include a fitting guide with their diagnostic fitting set and guidelines on which lens to start with either based on care otama tree values or starting with a standard lens vault or even starting with the lens from the middle of the set and I cannot stress to you enough how important this initial step can be most of these manufacturers have put in countless resources in developing their individual scleral lens design and so the fitting guide that they've prepared you know is is a very very good manual for your success so I would highly recommend following the fitting guy to get started and like I said all fitting guides I'm sorry all lenses lens designs typically come with a fitting guide and then most manufactures also have consultants available at your disposable that you can quickly call or chat online with over email and get any ideas on where to start if that's where you're kind of stuck alright so preparing the lens so first and foremost preparing the lens for application is of an important step make sure the lens is cleaned with appropriate gas permeable cleaning solution wash your hands and prepare the large plunger for application so as a reminder we typically use large DMV plungers for insertion and then a small DMV plunger for removal so in preparing the patient it's always helpful to have paper towels or something covering their lap so that their clothes don't get stained because it inevitably will have some fluid leakage as you insert the lens into the eye so it's helpful to prepare the patient with giving them paper towels ahead of time so that they're ready to go to capture any of the fluid floss on the plunger you want to Center the lens onto the plunger if the lens is d centered that's gonna cause some of the fluid to spill out and also it'll you won't be able to insert the lens centered on the eye as well and that'll cause a bubble to form you'll have to remove the lens and reinsert so it's always a good idea to get that lens nice and centered on the plunger to begin with the large d MV plunger has a suction on it so that when you're putting the lens on the lens can be nice and centered on the plunger and then nice and centered when you're putting the lens in the eye now an important thing to remember is you have to release the suction as you let go of the plunger as well when you're inserting the lens and I'll go over I'll go over that in a little bit more detail some practitioners and even patients don't like the suctioning aspect as it might be too difficult to press the suction to release so I press the plunger to release the suction so an option is to cut off the end of the plunger here so that there is no suction anymore now this also serves to give the patient a little bit of a fixation target as they look into the plunger because they can see right through it so it kind of helps in in those two regards overflowing the lens to ensure that no air gets trapped under the lens now this will serve to reduce any bubble formation underneath the lens and then you're you're filling the lens bowl up with non preserved saline so these are some of the saline that we use in clinic just as a side note insurances may cover this for the patient so I typically send a prescription to the patient's pharmacy and it's written as a single unit dose of 0.9% inhalation saline which is this a Deepak here now lacquer appear in the United States has been FDA approved to be used in the eye I'm not too sure about sclera but have a feeling it's also been FDA approved and then pure lens is a bottled form of non preserve saline as opposed to a single unit dose so again this comes with restrictions on you know when when you should throw it away within a certain period of time so inserting the scleral lens so the sclera lens should be placed on a large or medium DMV suction cup to aid stabilization of the lens during handling alternatively the patient can use a tripod method using their thumb index finger and middle finger to hold the lens the lens should be filled with non preserved saline solution and when I say filled I mean overfilled so make sure the lens is overfilled with non preserve saline the patient is instructed to lower their head so that their face is parallel to the floor this allows the lens to be inserted from below so that they'll fluid in the lens doesn't spill out this is important to avoid bubbles if a bubble is present you'll need to remove the lens and reapply the lens otherwise it can lead to an area of corneal desiccation it's important to hold the upper and lower lids both lids wide open and have the patient look downwards toward the floor I typically have the patient hold their own lid because it helps me kind of brace the lens a little bit better but you have the option of holding both lids yourself as well another tip is to remove quickly and smoothly move the lens up onto the ice contacts the sclera it's important not to push too hard as you insert the eye insert the lens onto the eye the great pressure can cause a you know a lot of redness around the conjunctiva if it's squeezed up too hard once you've come in contact with the eye you want to squeeze the suction cup so that's a lens releases on to the eye just have the patient close their eye and make sure the patient has a paper towel or a tissue to to just catch that overflow like we spoke about earlier you want to check the fit of the lens in the slit lamp and also to check to see if there are any bubbles present because remember you'll need to remove the lens and reinsert it again so patient positioning remember the head needs to be parallel to the floor what I like to do is actually raise the patient's chair all the way up so that they're matching my height and then I'll have the patient lean their head all the way down this helps me so that I'm not you know crouched underneath trying to get the lens on if a patient has a very strong bell's reflex you might want to give them a target to fixate on so that they're looking at that as you're trying to apply the lens on their eye now the eye should be centered between the lids for proper application and then of course you can have the patient hold their lower lid in place as well so that it's a little bit easier for you to just grab the upper lid so you want to retract both upper and lower lid and move quickly so with the other hand you can hold your plunger and you want to come around around the patient to hold their upper lid kind of locking their head into place you want to be careful I mean you don't want to add too much you know force there but you still want to kind of gently hold their head in place so that you're bracing their their head and they're not kind of moving all around you need them to stay stationary as you apply that lens it also helps to sometimes brace your hand with the plunger against the patient's cheek as you're inserting the lens this reduces a risk of losing fluid and then once again it improves some of this study 'no sand aim as you apply the lens move quickly you want to squeeze the plunger as as you apply the lens pull the plunger away and then release the eyelids and then let the patient kind of blink a little bit and then you hot you want to check for bubbles right away to make sure that you don't have any insertion bubbles this is an example of a large insertion bubble so something like this requires an action on your part you remove the lens and reapply this is a great resource by a Bosch and loam that I give to my patients typically I like to recommend the plunger method if a patient is you know a little bit fearful of the plunger method then I'll recommend the three-finger method but this resource I'll give to them as they leave as they leave after their insertion removal training because sometimes patients have a tendency to forget out what we spoke about so that they can quickly reference this and I have linked the website below for you guys here if you want to access this resource and it also has the three-finger method as well for any patients that like I said might be fearful of the plunger method there are fixation targets and other devices available and for patients that have issues with mobility or dexterity concerns so just because a patient you know has limited movement it doesn't mean that they can't be a good scleral lens candidate and where sclera lenses and there are other options to improve to help with weight with this all right let's talk about removing the lens so lens removal you want to use a small DMV suction device for this without a hole and there's there's two variations of the small suction device one has a hole and then the other one does not I might prefer the one without the hole in it have the patient look down with their head in upright position and then you know you can also have them lean it against the headrest hold the patient's upper lid out of the way place the suction cup on the superior portion of the lens as close to the lens edge as possible and then gently rock the lens to release the suction between the lens and the once that suction is released gently remove the lens rotating it forward and upward and off the eye it helps to have the patient look up after suction as released to just helps to rotate that lens off the eye for a smoother removal so here you can see that the patient is sitting upright eyes are lowered and then you're retracting the upper eye I typically only retract the upper lid but you can retract the lower lid too if you feel that's necessary apply the top edge of the plunger with the top edge of the lens tap the plunger onto the lens and then gently break suction and then arc downwards like your if this is you know the cornea and this is the lens you want to kind of move villain move the plunger in this fashion and then you can instruct the patient to look up because that'll help to kind of take away the suction as well and I have a video here make sure to overfill it so do you see a large tear meniscus right yeah slowly approaching the eye squeezing the plunger and pushing the lens onto the eye noting some of the extra fluid will drip down squeeze and attach the small DMV plunder to the lower edge of the lens freakin suction and pulling the lens off the doctor can also brace the upper lid had the patient pull down the lower lid and slowly insert the lens squeezing the plunger as the lenses put on to the to remove the doctor has the patient looked down squeezes the smaller plunger near the upper edge of the lens breaking suction removing the left lastly it's very important to look for bubbles bubbles can interfere with vision and also caused decreased comfort any large bubbles as seen here the lens must be removed and reinserted without any bubbles all right so we're onto our poll question number two which of the following is true regarding applying and removing sclera lenses they use a small plunger to apply large plunger to remove so this is just a test your knowledge of what we just talked about be cutting off the large plunger helps with centration when entering the lens see there are no fixation devices available for patients with limited dexterity or d tripod or the three finger method is an alternative for patients fearful of the plunger method excellent so most of us got that one correct so the tripod of the three finger method is an alternative for patients fearful of the plunger method now remember the large plunger is used to insert the lens and then the small plunger is used to remove the lens we want to our a poll question number three I think I made my point with this one fairly clear so let's see if we got that point across if you see a bubble underneath the scleral lens what should you do a push up method to dissipate the bubble B do nothing as the lens settles the bubble will dissipate on its own C remove the lens through the lens with non preserve saline and reapply the lens or D rotate the lens until the bubble dissipates excellent so yes most of us got that correct we should be removing the lens fill the lens bowl with non-pressure of saline and reapplied lens one quick note on there is to just know that if it's a very tiny bubble and that's kind of moving in its place not causing any disruption to the vision or comfort that may be okay when we refer to taking the lens off and reapplying we're referring to large bubbles that you that you want to avoid alright moving on to assessing scleral lens so steps for assessing the scleral lens I typically like to take what I call the center out approach which means I assess the central clearance values first so I assess the apex of the cornea first and then I move to the mid peripheral zones so if a slit-lamp image looks like so I would look at this area first and then move out outwards and then move my beam this way and move it that way it's important to evaluate the limbal zone and then evaluating the sclera landing zone or where the the lens comes into contact with the eye also important to evaluate the overall saturation of the lens because of the optic zone is d centered too much than the patient's vision will not be as optimal and then assessing the movement of the lens is important as well making sure to document these findings is just as important as evaluating them there's so many numbers that get thrown around what's lera lenses that it's very important to keep that all clear and concise so documenting you know the clearance values that you're noting first you know before the lens has settled what I like to do is when I'm evaluating I always write down what how long the lens has been on the eye for because then it gives me an idea of how much settling the lens has to do or if it's kind of in its final stages of settling determining the essential corneal values is very important all right give me one sec here you so determining the clearance values using a slit-lamp technique most practitioners use this and this is the technique I would recommend for anyone that doesn't have any OCT available you want to make a very thin optic section use white light and make about a 45-degree angle and you want to use so similar to the von Herrick technique you would use to estimate the angles so a thin optic section of white light approximately 45 degree angle most practitioners use the lens thickness as a reference which is which is what you should do if you use a cornea if it's a normal cornea that's absolutely fine because we know approximately it's around five hundred thirty microns however irregular corneas corneas with keratoconus we know that they're unpredictable so sometimes that's not the most accurate way of measuring the clearance of the lens clearance underneath the scleral lens so I would recommend using the known thickness of the scleral lens because it's a better reference point for you it's estimated that the human eye is capable of observing about 20 microns or more so less than that to us appears as black so but this doesn't necessarily mean that there's Frank touch it just means that it's something that we cannot see and that's when the fore OCT becomes more valuable fluorescein applying that to the lens bowl you know where the Saline is in you know applying a dip of fluorescein is also helpful when the lens goes on and I'll show you guys this in a second here and even what was observed here as you can see that the fluorescein makes it a lot easier for us to see how much clearance there is underneath the lens and then one interesting study conducted by the University of Waterloo's show that there is a consistent underestimation of about 50 microns between pencil absolutely I'm technique and ultrasound technique and this is this was regardless of experience of the practitioner with clear lens fitting I'm so that's something important to note as well lens assessment I like this schematic to show you guys this is the lens here and this is the tear film dipped in the fluorescein reservoir and then your cornea here so when you're looking at a cross-section of a scleral lens and assessing it this is similar to what you're going to see now the distance from the posterior lens to the anterior corneal surface this here is what we're measuring when we're talking about the clearance value of sclera scleral lens or vault of a square öland and once again a good reference point is the lens thickness as opposed to the corneal thickness which can be very variable and sometimes we don't always have that information available whereas the lens thickness most of the manufacturers will give us that lens thickness whereas we're fitting the lens and then you want to move on to the mid periphery of the lens and evaluate that from from the center onwards and then of course we want to make sure we're not resting on the limbal zone there because then we're resting on the limbal stem cells and that can cause trouble as well when we're measuring the corneal vault we're measuring it in microns and as the lens settles particularly in new wears the lens will settle more so as it settles we'll we're going to see a decrease in the amount of clearance that we're seeing and typically it decreases about a hundred microns or so and most of the settling takes place in the first two hours of wear but the full amount of settling can take up to eight hours so I usually have the patient when they're coming back for an re evaluation I make sure that they've at least worn the lens for two or three hours so that I can see what the lens looks like post settling alignment of the lens with the scleral shape is important in preventing any air debris from getting trapped underneath the lens too tight of a square landing can lead to complications such as blanching compression and impingement typically assessed by observing the lens bearing with a trial ends so once you get your trial and set you put it on and then you want to take a good look at the periphery and see what changes you want to make other factors that we spoke about already the toric peripheral zones you know you want to assess the movement you can add fluorescein on top of the lens as well to help with identifying the outer edge of the lens as well if you have trouble seeing that through slit-lamp and this is what they've done here actually so this is Ferris State University developed a fit scale based on utilizing fluorescein to estimate the vaults values in this case the center of thickness of the lens is I defined as 300 microns so you can visualize this one-to-one relationship here so 300 microns of the lens thickness and then 300 microns of the tear reservoir underneath the lens and then here's our cornea here so applying fluorescein to the front surface of the lens can help to identify what the top looks like and it kind of gives you a good outline of where the lens is here you can see 50 microns and how faint that line is there 500 microns kind of getting a little bit closer to the cornea here 150 microns this is kind of what we expect when the lens has settled onto the eye 600 microns we want to reduce some of the clearance there and then I'll let you guys look at this on your own here but it gives you a good idea of what the limbo vaulting should be - you kind of want to have a little bit so about 50 microns - 100 microns of limbo volt left over after the lens has settled sometimes if there's too much limbo volts and then you're you're limiting oxygen getting into the eye as well this is a good example of what a picture of sorry good example of what it looks like underneath the slit lamp here and we can see that the lens here there's judging by the way the fluorescein pattern is underneath the lens we can see that the lens is slightly be centred inferior ly because we're seeing a lot more clearance inferiorly compared to superior here and we might even have some touch here it's a little bit hard to tell with this little bubble but you can tell that the fluorescein actually increases as we go as we evaluate inferiorly so indicating that the lens's is is dropping these are some pictures of sorry the ideal picture here of what the edge alignment should look like so this is what I would call scleral alignment where the scleral lens of landing evenly onto the sclera here we're starting to see blanching which can lead to issues with discomfort and redness associated with longer wear times and then this picture here we're seeing edge lift which can result in lens edge awareness upon blink and it indicates a too flat of a of a peripheral edge and this usually leads to problems with debris getting underneath the lens and building underneath the lens and getting that snow globe type appearance we talked about earlier so in this case look for a dark band or shadow to identify any LED lens lift and then insufficient edge lift if it's too tight you can limit to your exchange and that can pose a problem of its own as well so I'm coming to our poll question number 4 this is a little bit of a challenging question here which of the following best describes this fit pattern so is it a excessive edge lift be adequate scleral alignment see impingement or debranching yeah that's what I expected and we're seeing a kind of some even answers here so this was a trick question and I my apologies for making it a little bit tricky here for you guys so these is what we call elbow compression so what's happening here is that the lens is actually landing here as opposed to landing all the way to the far edge of the periphery okay so this there is a little bit of blanching so those of you that said blanching that's correct and then there is consequently some edge lift here too which you guys can see a little bit of that shadow so this is a scenario where we're kind of getting both aspects so we're getting blanching as well as edge lift and some ways to alleviate this is to pick a lens that's a little bit smaller so that that the edge actually lands here or you can steep and up the the peripheral curves here so that the lens actually lands in the far periphery as opposed to the mid haptic zone here and then I want to touch base on using anterior segment Oct with sclera lenses a lot of us now do have access to a OCT and this is certainly not necessary to fit us Clairol lens but it is very helpful in cases where you know you're not a hundred percent positive in assessing the way the lens appears whether there's too much corneal volts too much scar lens walt or too little stir lens well where you're not necessarily sure if the lens is touching or not sometimes I like to take it behind the Oct just to confirm my findings as well so it also gives us an exact measurement of the central vault mid peripheral limbo vault and it can give us an idea of the lens edge profile as well so to give you an idea of what some images look like here so this is the cornea here our sclera lenses up top here and then you see the fluid layer over here now there's this is these images were taken using a serous anterior sight guideline raster you can use a caliper to measure the amount of corneal clearance underneath the scleral lens which I like to do a lot to just see exactly how much clearance there is underneath that lens so you can see here 300 microns is preferable as you insert the lens and then you expect it to kind of settle down to about 160 100 100 and 200 microns so 166 is is excellent it can also help you identify if there's things in underneath the lens trap debris underneath the lens and you can see these little flecks here that represent some debris trapped underneath the lens and then it can also help you identify areas of touch so you can see here the lens itself is landing and touching the scleral lens here I know that this is a wide-angle view the ability to do that is is with a attachment on our Oct but the the wide-angle helps us to kind of see the total edge probe sorry all corneal sagittal depth with the lens as well but again we can see there's some touch here you all right and I'm gonna skip this slide real quick but there are additional benefits to using an Oct in the interest of time you guys can read this on your own but a scleral lens Oct can sorry an anterior segment Oct can also help with identifying not only the lens thickness but also the corneal thickness if you're worried about edema developing so you know taking pre and post Clairol lens where images on the Oct is helpful this is a full picture of what you end up getting once you take an image on this year's Oct so here there's a cross-section here and it gives you about five five line rasters and then once again it can help you identify even the most minimal amounts of corneal fault so this is a patient where I wasn't sure if I had enough corneal thickness over the apex so I did bring them here to to check with the Oct and in fact we weren't touching we were we had about 16 microns clearing and then in some cases when there's far too much clearance it helps to also get an Oct because at some point it just becomes too hard to estimate exactly how many you know lens thicknesses will fit in this range so sometimes it's just easier to put the patient behind the Oct to get those numbers those exact numbers I really like to also look at the edge of the scleral lens and how it lands and comes into contact with the conjunctiva and the Oct can be helpful in this case as well this patient here that we're looking at the top two images he kept complaining about lens awareness and every time I would look at the lens I I thought to myself you know it's well aligned I really don't want to tighten it anymore so I was convinced that you know he was imagining this but when I put him behind the Oct I was able to appreciate a little bit of lift here as you guys can see so you know it does kind of help to confirm your findings behind the slit lamp this is an example of severe impingement where the lens is digging into the conjunctiva what you want is a this picture here is an ideal definition so what you want is about a 50/50 50% of the conjunctiva into sorry 50% of the lens into the conjunctiva so that's kind of what we see here where you're seeing it's kind of peacefully and gracefully land on that squirrel onto the sclera once again this is good squirrel and alignment here as you can as you can see and I do like to play around with the colors as well as sometimes it helps me you know see things a little bit better and in greyscale as opposed to the colors once again a severe impingement where the lens really is digging into the conjunctiva and causing some conjunctiva to lift up so this is what we call impingement where the lens is digging so hard that's from the conjunctiva is lifting up right brings us to our last poll question when estimating the central corneal clearance of this lens based on the slit-lamp photo assume central thickness of the lens being 250 microns what would you estimate to be the clearance a 300 microns B 500 microns C 100 microns or D 25 microns all right so the 25% that got 300 microns a great job so I just want to go over that real quick again because 50% of us thought it was 100 microns so looking at the front surface of the lens of this refractive area here is the outer surface of the lens so the outer edge of the lens and then the little space here is the lens thickness itself and then where the green area starts the looks like it's fluorescein there so where that green area starts is the back surface of the lens so from here on to here is what we're measuring and if we say this area here is 250 mile and you know this area here is very similar in size to that so maybe slightly larger so we could say it's about 300 microns all right other considerations and we did talk about this in detail about closely evaluate the need for an asymmetric lens design on the on the back surface so if we need to work peripheral curves a lot of lens designs now offer you know Touareg peripheral curves and even quadrant specific designs are getting more and more readily available make sure we have a proper and stable fit before you start to do an over refraction - and determine the best corrected vision through the lens and then evaluate for tear exchange and then at each follow-up make sure you're removing the lens and staining the eye to check for ocular surface abnormalities any staining if there's any toxic reaction with punctate staining that you can pick up sometimes the patient you know won't be exactly sure on what to fill their lens bowl up with and they'll fill it up with multi-purpose soft lens solution and then they end up getting a toxic reaction all over their cornea from the preservatives that are in that solution and then any impingement staining so a you might notice a compression staining once you remove the scleral lens and if it's you know not too deep into the conjunctiva sometimes that's okay because you know the lens has been resting on the eye for eight plus hours or so but if it's if it's too deep and causing some staining around that area then that that fit needs to be flat and the peripheral edge needs to be fund so scleral lens care will quickly go over this so GP care solutions or peroxide systems are useful with sclera lenses as well care should be taken when cleaning and rinsing the lenses due to the fragile nature you still want to instruct the patient to rub each side of the lens inside and outside with cleaner for about 15 seconds there are larger cases available for patient purchase as well so that the scleral lens can fit nicely into the case if you guys have clearcare in in in the countries essentially clearcare sometimes can be too small for to fit a squirrel and so the larger chamber case definitely helps GP solution should be rinsed from the scleral lens with sterile non preserve saline prior to insertion and then if the patient is not planning on wearing the lens for a while then storing it dry is the recommended way to go and then diagnostic lenses or any lenses that are in your fitting set that you used to fit the patient should be cleaned and disinfected properly with either using a GP disinfectant solution or hydrogen peroxide and then stored dry plungers you can clean those with soap and water hydrogen peroxide alcohol wipes and then supplement supplemental products such as artificial tears to lubricate the surface on top and then cleaners such as some alcohol based cleaners project is very helpful too it's a deep deep cleaning for the lenses and then the Boston one-step enzyme is also a stronger cleaner that I would recommend your patients use either you know every two weeks or every week depending on how much debris and build-up they get on their lens and each visit remember to you know review lens care and insertion removal especially if the patient is new to sclera lenses I find this by the AOC le healthy habit sheet very helpful when I'm dispensing the lens it has this little little area here for writing down what they should be using to clean the lens what they should be soaking the lens in and then what they should be filling in the lens bowl so typically I let the patient leave with a lot of resources after the fitting their initial dispense so that if if you know they missed anything I said because I'm giving them a lot of information on that visit if they've missed anything I've said it's it's readily available for them to read and then lastly I just want to point out to use your resources so there are multiple training video that the manufacturers will put up on their websites for their lens designs on their certifications kind of like quizzes that you guys could take as well and then consultants are always available for us for troubleshooting ordering lenses you know running anything by them they're available at our disposal I use them all the time to help me with my fits so yes and that's it just want to thank dr. Andrew McLeod and our contact lens department at neck Oh for some of the support and I'm happy to answer any questions we have at this point thank you dr. Kumari so we have I think having the questions if you want to just stop your screen share and open up oh sure all right so the first question I have is what is the technique of the scleral lens all right so I'm not exactly sure what you mean by that if you want to elaborate on that question I'd be happy to answer it some more okay is it possible to eliminate myopic of that patient using this so I think this question if you're asking about refractive correction and whether or not you can use sclera lenses for refractive errors absolutely if you have a patient with high myopia and you want to put that prescription into the scleral lens you can absolutely do that and and they will get far superior vision compared to a soft lens now if you're asking about orthokeratology which is a little bit different where it's a small diameter reverse geometry lens that compresses the tear film on the on the cornea that's a little bit of a different concept than sclera lenses so in that case you know we don't do any overnight wear with sclera lenses or reshape the cornea in any way with sclera lenses okay next question is corneal sclera lenses still being prescribed will there be no new vascular ization in cornea on long unlinked on long time use all right that's a good question so yes so corneal sclera lenses are I would say they're not being as utilized as frequently as they previously were with the advent of the sclera lenses being larger and more commercially available a lot of practitioners are using the full sclera lenses so that there's limited contact with the limbal area there now if there is a lot of Vault in that limbo area or if the patient is wearing the lens for too long or sleeping in the lens or anything that is non-compliant and you know non-compliant then we may see some neovascularization starting to form however with the advent of really good gas permeable lens materials hi DK materials we're seeing less and less i knew about euler ization than we were seeing in the past Cancellara lenses befit in cases with scleral thinning you have to be careful with scleral thinning because you you want to make sure that there is no impingement or no Frank compression in those areas so I would be very careful I would probably work closely with a corneal specialist if I'm fitting a patient with severe squirrel thinning you'd like to know the axis stabilization in sclera lenses so I'm not too sure about that question either if you wouldn't mind kind of elaborating on what you mean by axis stabilization in sclera lenses I'd be happy to answer that question as well and then the next question I have here is the solution which is put in into the vault how long does it stay for dry I patience for the most part the solution stays throughout that time of the the patient wearing the lens so there's very limited tear exchange that does go on but if a patient a lot of my patients like to you know because the lens always feels much better when they first insert it then after you know five or six hours of wear so a lot of them especially my dry eye patients will like to take the lens out rinse it and then put the lens back in so they have fresh saline and fresh solution bathing their cornea but technically it's good to last you know up to eight to ten hours who is classified or qualified to fit sclera lenses so anybody that you know has had the training and kind of knows enough about sclera lenses to feel comfortable with fitting sclera lenses can do so I would say you know get very familiar with one type of scleral lens get to know it really really well so that you're able to be almost an expert in that scleral lens and again you can use you know the consultants or the manufacturers to help you with help you with fitting that lens to you have you checked or any problem with IOP and sclera lenses are you asking if there's a concern for an increase in IOP with sclera lenses if so then the no there is no concern for increased IOP with sclera lenses I think in one of the the pre-registration questions someone had asked if there was a way to monitor IOP with sclera lenses and as of now I don't think so but I think that that idea is underway I know for sure it's under way with soft contact lenses and it's been tested multiple times and I'm pretty sure it's under way for sclera lenses as well so if the center if the lens is centering inferiorly it's a great question there's a few things that you want to look for so if you have too high of a central corneal vault you want to first start to reduce that that central corneal vault because what's happening is that there's a lot of fluid reservoir underneath the lens so it's causing the lens to dissenter the other thing you want to check for is the peripheral tour City to make sure that the entire periphery of the lens is landing evenly so what can happen is if there is a lot of Teresa T in the sclera and the there's a mismatch between the way the sclera lenses aligning with the sclera there's two edges of the sclera sclera lenses that are landing much harder than the other so that's not enough pressure to keep that lens in place so it ends up D centering inferiorly so you want to make sure that you add some torres peripheral curves to better align the entire you know 360 of the scleral lens it will have one more what can be done oh this is an excellent question so if you find that the removal small removal plunger is um your your lenses to tighten you're having trouble you know removing the lens what you want to do is use the patient's lid to push up and over and create a bubble underneath the lens so in this case you want to create a bubble to break the suction between the lens and the conjunctiva and that has come in to come handy a lot for me so once you get that bubble in there it breaks the suction and then you can easily remove the lens all right thanks everyone for your time