The College of Optometrists

Could someone please advise me of the best way of adapting routine(mainly retinoscopy and subjective refraction) for the following patients: 1)Nystagmus 2)Amblyopia 3)strabismus thanks

1) don't occlude the other eye - it will increase the nystagmus = occlude it with a big plus lens instead.

Don't use small steps unless the vision is good - and don't aim for perfection - they want something they can use. Use the smallest cyl power you can get away with adults. If they young enough to visually train - then full cyls.

2) Adult amblyopia - discuss with them if they want the whole Rx or balance (many visually prefer a full Rx). Minimise the cyl - unless its astigmatic amblyopia.

Children should have full Rx as gained by cyclo. this is especially true of astigmatic amblyopia.

Amblyopia due to anisometropia Rx should also be fully prescribed

I will write more on this for you - but its getting late - all the best = steve

Amblyopia due to anisometropia is more likely in hyperopia than myopia. This maybe due to the increased accomodative effort in hyperopia. This is why you may concider a cycloplaegic prior to testing in children. -hop it helps = steve

Re Nystagmus: I am in slight disagreement here, Steve. Patients with Congenital Idiopathic Nystagmus or nystagmus associated with a condition such as Albinism, aniridia, has excellent powers of discrimination. Despite having a low VA they may be able to easily discriminate a +/-0.50 difference in sphere when presented. And aim for full cyl correction. It may not make a difference in central VA but is important when it comes to peripheral acuity. During your routine, allow the patient to adopt any abnormal head posture (AHP) that they may have developed as a result of their nystagmus. In so doing they must be allowed to find their null point, if they have one (most do). It is at that point they will have maximum discrimination. Avoid using a phoropter head and use a trail frame. For those who are additionally light sensitive (aniridics, amblyopes, rod monochromats)they may prefer to have the back illumination of the test chart switched off. Disability glare will cause their VA to drop. In addition, as Nystagmus increases with stress (and not just visual stress) then keep them comfortable. Any increase their amplitude of nystagmus will result in a reduced VA and subsequently a less accurate end point to your refraction.