You see an eight-year-old boy who is a new patient and has recently had his eighth birthday. He has a visual acuity of right 6/5 and left 6/12 with his glasses which he wears constantly. He had his first pair three months ago.
His refractive correction is right +0.50 DS and left +3.00/-1.00 x90 and you have ruled out a sinister cause for the reduced visual acuity in the left eye and there is no strabismus. What are the treatment options for the reduced visual acuity in his left eye?
My first step would be to check the refractive correction. I trust my own work best and trust the work of a handful of colleagues but that’s it. I would carry out a ‘dry refraction’; retinoscopy first and then subjective refraction. Followed by a cycloplegic refraction irrespective of the results from the ‘dry refraction’.
I always remember a case where a nine year old boy who was having reading problems. He seemed to be +3.00 DS each eye on ‘dry refraction’ but cycloplegic refraction showed +9.00 DS in each eye! For the case in the question, I would then prescribe the optimum refractive correction and recommend he continued full-time wear for all activities and all waking hours. It’s popular to think that after the age of seven that there is absolutely no chance of any improvement in visual acuity for an amblyopic eye.
However, there is plenty of good research evidence, especially for anisometropic amblyopia that visual acuity can be improved after this age. As he is near the seven year old timeline for correction of amblyopia he may improve. I remember another patient with a similar prescription aged nine who had never worn glasses.
His starting visual acuity in his weaker eye was 6/60 and he managed 6/9 after around six months of full-time glasses wear. Back to our case. If after a month of wearing the new glasses the visual acuity remained at 6/12 I would advise occlusion therapy for two hours per day after school with the patch being placed under the glasses and over the right eye for one month and then review and then one further month depending on the visual acuity achieved after the first month of occlusion.
If the visual acuity improved then good. If not, then I would advise the boy and his parents accordingly about the positive prognosis. Contact lenses could be an option but there is a concern about future traumatic damage to the right eye without glasses being in the way to protect, if the visual acuity remains at 6/12.