today I will discuss about positive relative accommodation and negative relative accommodation positive relative accommodation and negative relative accommodation measure the maximum ability to stimulate accommodation while maintaining binocular single Vision NRA and P helps us to determine normal accommodative functions accommodation access accommodation insufficiency status of fusional convergence status of fusional vergence and determined refractive Corrections now the question is why it's called positive or negative relative accommodation in positive relative accommodation accommodation is stimulated with minus lens that's why it's called positive relative accommodation and in negative relative accommodation accommodation is relaxed with plus lens that's why it's called negative relative accommodation so when accommodation is get stimulated or activated it's called positive relative accommodation and when accommodation get relaxed then it's called negative relative [Music] accommodation now what are the prerequisites for the test refractive status distance correction should be placed in the trial frame before starting the test room condition room condition should be daylight condition Target near vision chart or card fixation size n6 Target or last line easily read by the patient in near vision chart test distance 40 cm in front of the patient trial box will will be needed positive and negative lenses trial frame now let's see how to measure positive relative accommodation ask the patient to sit comfortably and H the near Vision Target at 40 cm patient fix it at the N six Target or the last line he or she can read comfortably now minus lenses are slowly added binocularly in 0.25 diap steps until the patient reports first persistent blur here for this patient we have added minus 0.25 binocularly and Pati is seeing the near Target clearly so we have to increase minus 0.25 diaper steps so let's add - 0.5 diap still p is seeing clear let's add more with minus 0 75 still clear let's add more with minus1 still clear let's add more with -1.25 still clear let's add more with - 1.5 still clear let's add more finally withus 1.75 patient is seeing that there is a persistent blur remember place the second lens in trial frame before removing the first lens the power of minus trial lens required to make the Target first persistent blur is the value of positive relative accommodation so this 1.75 dapor will be positive relative accommodation value now interpretation of positive relative accommodation test expected positive relative accommodation value is in between -1.5 diap to minus 2.5 dapor it will be normal accommodative function if positive relative below Falls between - 1.5 diap to - 2.5 dapter it will be accommodation insufficiency if positive relative accommodation value is less than minus 1.5 diap it will be accommodation access if positive relative accommodation below is more than minus 2.5 diap there will be inadequate FAL Divergence if positive relative accommodation value is less than minus 1.5 dapor because minus lenses in positive relative accommodation testing induces accommodation and increases accommodative convergence due to the AC by a link in order to maintain clear binocular single Vision the ice must neutralize the accommodative convergence by fusional divery response inadequate fusional Divergence can therefore limit the end point of positive relative accommodation measurement positive relative accommodation can also identify U corre in hyperopia and under correction in myopia High positive relative accommodation value can be indicative of over correction in hypermetropia and under correction in myopia you might be thinking how does positive relative accommodation can identify overcorrection in hyperopia and underc correction in myopia let's see in the next slide in both condition U correction in hyperopia and under correction in myopia RIS focus in front of the retina to shift the race in the retina we need certain amount of diverging or minus power this extra minus power will be added to the positive relative accommodation value which results high positive relative accommodation value in U corrected hyperopia and under corrected myopia so if patient accommodation response is normal but showing High positive relative accommodation value then it indicates U correction in hypermetropia and under correction myopia is done during the refraction now how to measure negative relative accommodation ask the patient to sit comfortably and H the near Mission Target at 40 cm patient fix it at the n6 Target or the last line he or she can read comfortably then plus lenses are slowly added binocularly in 0.25 diap steps until patient reports first persistent blur the power of Plus trial lens required to make the Target first persistent blur is the value of negative relative [Music] accommodation now interpretation of negative relative accommodation test expected negative relative accommodation value is in between + 1.75 diap to plus 2.5 diap it will be normal accumulative function if negative relative accommodation value Falls between + 1.75 diap to + 2.5 diap it will be accommodation insufficiency if negative relative accommodation below is more than plus 2.5 diap it will be accommodation access if negative relative accommodation value is less than + 1.75 diap there will be inadequate fusional convergence if negative relative value is less than plus 1.75 rapor because addition of plus lenses relaxes accommodation and stimulate Divergence due to AC by a link in order to maintain clear single binocular vision the ice converts or use fusional convergence inadequate fusional convergence therefore can reduce the end point of negative relative accommodation negative relative accommodation can identify Uber correction in myopia and under correction in hyperopia High negative relative accommodation value can be indicative of over correction in myopia and under correction in hypermetropia you might be thinking how does negative relative accommodation can identify U correction in myopia and under correction in hyperopia let's see in the next slide in both conditions U correction in myopia and under correction in hyperopia raise Focus behind the retina to bring back the raise in the retina we need certain amount of converging or plus power this extra plus power will be added to the negative relative accommodation value which results high negative relative accommodation value in U corrected myopia and under corrected hyperopia so if patient's accommodation response is normal but showing High negative relative accommodation value then it indicates over correction in myopia and under correction in hyperopia is done during the refraction stay with smart Optometry and study Optometry [Music] smartly