hello and welcome to Insight oftalmology I am Dr Amit welcoming you to another lecture on accommodation and today we are discussing the various anomalies of accommodation Duke and Elder basically classified accommodation anomalies into two broad categories so we have the anomalies arising because of excessive accommodation and we have anomalies arising because of diminished or deficient accommodation on one side you have excessive accommodation and spasm of accommodation and on the other side we have physiological dimin of accommodation which is seen in press biia pharmacological decrease in accommodation which is seen when we take some cyclopic drugs like atropin or homatropine resulting in cyclopia or it could be pathologically diminished accommodation here under the pathological decreased accommodation we have four accommodative anomalies number one is accommodation insufficient number two is ill sustained accommodation then we have accommodative inertia and accommodative paralysis first of all let's talk about the insufficiency of accommodation so what is insufficiency of accommodation the accommodative power here is less than the normal physiological limits for that patient's age so that is the key word it is less than the normal physiological limits for that particular age group now this should should not be confused with press bopa where the insufficiency is age appropriate now how do you basically find out the expected amplitude of accommodation for that particular age we have to use the Hof stus formula the hofus formula is 15 minus .25 into age of the patient so for example if the patient's age is about 14 years the expected amplitude would be around 11.5 diopters and if the patient has say for example eight diopters of accommodative amplitude left now this indicates that this patient at the age of 14 years has insufficient accommodation now what causes insufficiency of accommodation it could be because of premature sclerosis of the lens or it could be due to causes either systemic or local causes which can cause weakness of the cery muscle now here this could be because of debilitating illness fever anemia fatigue even malnutrition diabetes toxemia pregnancy and even stress all these conditions can affect the CER muscle leading to deficient or insufficient accommodation also weakness of the CER muscle could be because of increased pressures as seen in primary open angle gloma or it could be seen in ocular inflammatory conditions which can affect ffect the seery body for example sympathetic ofalia onset as a matter of fact in syp in sympathetic ofalia we have this one symptom that patients present with and that is difficulty in Neo Vision task so what are the various clinical features as expected the patient is going to have visual symptoms associated with the near work so they will have difficulty in maintaining clear focus and really going to struggle with reading or close-up task and as the accommodation is less they're going to put more effort and that is going to lead to I strain and discomfort and sometimes even headache fatigue and irritation due to sustained accommodative effort now accommodation and convergence issues go hand in hand because we know that it's actually a synergistic process with accommodation we have convergence and that also stimulates that also constricts the pupil to meosis so here also you might have convergence issues and such patients are going to have intermittent diplopia while carrying out near work task okay apart from that there might be Associated symptoms like heaviness of the eyelid now this is basically the eye fatigue only and also let's talk about the stability and progression of these symptoms now if the patient has this accommodative insufficiency due to lenticular sclerosis or cact then the symptoms are going to be pretty much stable however if it is because of the sory muscle weakness like in systemic causes say a fever or any illness then the symptoms are going to be variable and this is going to depend upon the uh status of the celery muscle now what about the uh the test results so when we carry out various accommodative test in these patients so we talk about this accommodative test in our previous videos so you can visit those videos so here in accommodative insufficiency you will find that the amplitude of accommodation would be low also the near point of accommodation would be receded in monocular or binocular accommodative facility test you will find that the patient has difficulty in clearing the minus lenses why is that so because minus lenses stimulate accommodation and they have some sort of problem with accommodation and therefore they have difficulty in clearing the minus lenses when we talk about the negative relative amplitude of accommodation here it appears High and the patient is going to actually accept High plus lenses now why does that happen now the NRA or the negative relative U amplitude of accommodation basically represents the limit of relaxing accommodation before the patient experiences blur and here we will sequentially introduce plus lenses or the plus Powers now in accomodation in sufficiency since a patient already is under accommodating they can accept more plus Powers before noticing a blur making it seem like they have an excessive High excessively High NRA it's more of a relative excess rather than a true overactive response however when we talk about the positive relative amplitude of accommodation now this is basically about how much uh minus lenses you can add before the patient experiences a blur so this test how much you can stimulate the accommodation in this patient so since these patients have difficulty in stimulating accommodation and low amplitude of accommodation even the positive relative amplitude of accommodation is going to be low in these cases so that is something important they will have difficulty in clearing the minus lenses and the P values will be less than -1.75 diopters now what about monocular estimation method in ocular estimation methods again since the accommodation is affected or since the accommodation is less in these patients you are going to see that they will have this WID motion or WID movement and this indicates lag of accommodation so this diagram basically over here uh is the summary of all the test results that you're going to see in accommodative insufficiency so low amplitude of accommodation difficulty in clearing the minus lenses in accommodative facility test lag of accommodation with motion seen in mem retinoscopy P will be reduced NRA appears excessive very important all right now that we have understood what causes accommodation insufficiency and how do we interpret interpret the various results let's talk about the treatment of accommodation insufficiency now since it's associated with so many underlying conditions the primary treatment would be addressing the systemic cause of celery muscle weakness also we need to do appropriate refractive correction these patients are going to have symptoms with near task and therefore you can prescribe Neo Vision spectacles in the form of plus lenses to Aid in the near work the funa here is that you have to use the weakest convex lens that provides significant Improvement so you are just prescribing these plus lenses to basically help the patients with their symptoms we don't want the patients to become dependent on these plus lenses we also want to them to improve their accommodation and that happens basically with accommodative exercises so these accommodative exercises are going to Aid recovery once the underlying debility is resolved so the main treatment here is addressing the systemic cause and then prescribing the refractive correction Neo Vision AES and accommodative exercises there is a link between myopia and accommodation insufficiency in myopia usually the power of the eye is increased either in the form of coral myopia or lric myopia now since the power of the eye is more the patient has less and less need to accommodate and this results in development of accommodative insufficiency and therefore when we treating myopia you have to make sure that you give them full correction in the form of minus glasses any sort of undercorrection is going to worsen the accommodative fatigue by forcing more effort at near apart from that you can also consider giving them plus addition glasses for near and the plus lenses basically is a temporary way to relieve the symptoms with time you're going to slowly bring the plus lenses down to normal so that is one important point that we must remember so we talked about the accommodative exercises let's see what all accommodative exercises could be prescribed to these patients the patients can do flipper lens Associated exercises using using a plus two or minus two diopter lenses or customized lenses and this is going to help them in improving their accommodative facility we have previous videos on accommodation facility or accommodative facility now also push-up accommodation exercises can also strengthen accommodation and one more exercise is the heart chart exercise which basically enhances the accommodative facility and amplitude the first picture here depicts the push-up exercise so here the patient holds a pencil and they try to focus the tip of the pencil and they try to bring that pencil into one single Vision object now slowly the pencil is moved closer to the patient's eye till they experience blurring off the tip of the pencil once the tip of pencil appears double they try to make it uh they try to basically again push the pencil far away till it appears single so this is basically repeated again and again and this basically strengthens the patient amplitude of eom ation then we have the heart chart test here the patient holds a near chart like this and there's a distance chart present on the wall and the what the patient does is they will alternatively focus on the letters on the near chart and on the far chart apart from that lifestyle modifications like employing the 20202 rule is important after every 20 minutes they must take a 20 second break and look at something 20 ft away also ensuring that there is proper lighting and ergonomic positioning and also it's important to reduce prolong near work task without any breaks all right so we talked about the accommodation and sufficiency now let's talk about ill sustained accommodation so what is ill sustained accommodation here important is that the amplitude of accommodation is normal but it will fatigue quickly with repeated accommodative effort so these patients are going to have blurred Neo Vision after prolonged work they going to have acopia they're going to have difficulty with minus lenses and they're going to have reduced accommodative facility and therefore the diagnostic test will also be accommodative facility test in which these patients are going to experience fatigue with repeated cycles of near far focusing and they will have problem with the p specifically they will have decreased P wherein they're going to have problem with the minus lenses because minus lenses will stimulate accommodation and they cannot hold accommodation for long so I would advise you again to visit our video on accommodative facility test if you do not understand the same so how do you manage these here basically plus lenses again for new work this is only to alleviate the patient symptoms accommodative facility exercises like the lens Rock heart chart and the near far jumps now I explain to you what is meant by heart chart lens R test uh lens Dr exercises are also pretty similar here you're basically using flipper lenses for example plus two or minus 2 flipper or you can also use a separate plus or minus lenses you give the patient a near chart at 40 cm and patient alternatively tries to focus on the letters on the chart using the plus lens on The Flipper first and then the minus lens and they keep on repeating the process for about 1 to 2 minutes at a steady Pace the goal over here is to increase the speed and the accuracy in Shifting the focus between the lenses and of course you have to do the uh visual hygiene give the patient visual hygiene TP tips that is the frequent brakes and proper lightning condition the whole idea here is to improve accommodative facility now you might think what exactly is the difference between insufficiency and Ill sustained accommodation the primary issue in accommodative insufficiency is low amplitude of accommodation right from the uh start of NE Focus whereas in ill sustained accommodation the primary issue is not accommodative amplitude they have normal accommodative amplitude initially but this is going to fatigue over time with sustained near task all right the third one is the accommodative inertia and this is also known as accommodative INF facility here the patient has a delay in changing Focus between near and distance due to a slow accommodative response that means the patients are basically going to experience a transitory blur as they as they shift their focus from a near object to a far object or vice versa how do you treat them again you correct any refractory uh errors and also you have to prescribe them various accommodative facility improving exercises the last is the accommodative paralysis accommodative paralysis is a condition where the eye loses its ability totally to accommodate due to neurological pharmacological or pathological causes leading to difficulty in Neo Vision we all remember the accommodative pathway so what happens is the image is going to be formed on the retina goes to the optic nerve optic kaym optic tract latal geniculate body F to the visual cortex and visual Association area from here it reaches the superior ccul and pretectal nucleus goes to the Edo wpal nucleus from there it goes to the third nerve the parastic fibers are going to travel to the celer gangon synapse in the selary gangion and the post ganglionic fibers are going to reach through the short selary nerves to the celer muscle leading to accommodation so anywhere in the pathway there can be U some damage and that can cause paralysis of accommodation so let's see some of the common causes we could have congenital defect in which we could have absence or mal develop M of the celer muscle cyclopic drugs systemic drugs these can affect the pupil and these can also affect the celer muscle degenerative conditions like parkon disease also can affect the parasympathetic control of accommodation poisons cranial nerve three lesions ocular diseases like anterior UTIs and glaucoma they can also impact the celery muscle function internal opthalmoplegia can also affect the accommodation so in the end let's see how do we treat accommodative paralysis now if it is because of any drug drug induced paralysis like for example with with atropine or homatropine and even paralysis secondary to dpia often recovers spontaneously Over time however you can give patients symptomatic relief using dark glasses U these could be required temporarily to reduce glare and photophobia associated with accommodative paralysis also Optical correction can be given in the form of convex lens that is plus lenses basically prescribed to assist in Neo Vision so we know that during Neo Vision we are using accommodation and uh accommodation increases the power of the eye this I explained to you in my video on what is accommodation so since they have lack of accommodation it is logical that we prescribe them convex lens convex lenses it's pretty similar to what you do in presbyopia so in press biop also they have lack of accommodation or deficient accommodation and therefore we supplement that accommodation using the plus lenses now if your patient also needs glasses for distance you can give them the plus lenses in the form of bifocals or progressive lenses as well so those were four accommodative anomalies arising out of decreased accommodation if you like this video you might also like this video on accommodation thank you for watching have a nice day