Accentuated retinal rivalry results in OS suppressing OD with harmonious, anomalous retinal correspondence

Vision OD 20/20 OS 20/20 ET 5 D Alternating  Fixing with the left eye, central vision is 20/20 provided by the left eye only Peripheral vision would be contributed by both eyes, but the right eye would be suppressed, more so centrally. While binocularity is reduced, the peripheral visual field would be essentially normal.

Accentuated retinal rivalry results in OD suppression of OS with harmonious anomalous retinal correspondence

Just the opposite occurs in this patient when the right eye takes up fixation In this case with equal vision and alternating strabismus, with both eyes open, only one eye has normal vision, because the other eye is suppressed. However, peripheral acuity is not affected. This is similar to the patient with amblyopia under binocular conditions. The difference in the case of amblyopia is that only one eye has normal vision under monocular conditions. There is no spare!

This illustration can be used to encourage the family of a visually mature child (8 or 9 years) in whom amblyopia treatment has reached the best attainable level, but vision remains less than normal.

How much is my child handicapped, with best corrected vision of 20/20 in the right eye and 20/80 in the left?

Your child has 20/20 vision with both eyes open and a normal peripheral visual field, but should wear safety glasses, because he has only one normally seeing eye.

However, this argument should never be used in place of a concerted effort to achieve the best vision possible with amblyopia treatment.

It should also be recognized that amblyopia treatment in the anisometropic patient is often carried out successfully with glasses alone, or principally with glasses, and only minimal patching. This can be achieved in a child who starts treatment at 3 or 4 years or earlier and is a strong argument for preschool vision screening.

For example:

Vision OD 20/100 OS 20/20

Refraction OD +3.75 + 1.75 + 80 OS +1.00

Rx* OD +2.75 +1.75 + 80 OS Plano

Wear glasses full time and recheck in 6 weeks

* The sphere is reduced the same amount in each eye and the full cylinder is given in each eye.

Conclusion: Do the best job you can with amblyopia treatment, but if treatment falls short of ideal - cheer up the patient and family with the news that in most cases of amblyopia, binocular vision is not appreciably worse compared to the strabismus patient with alternating fixation but no amblyopia. The reality is that even with successful treatment of amblyopia with even small angle strabismus, high grade binocular function is rare, except in cases of anisometropic amblyopia treated early.

All patients with amblyopia should have safety glasses (even if plano) with polycarbonate lenses and preferably sound plastic frames with a secure lip to hold the lens in place.