Question:
My baby (congenital cataract) has been using a custom made hydrogel
contact lens from Alden Labs (+28 diopters, 8.3 base curvature, 14.5
mm). Our optometrist says that she has a "corneal irregularity" which
has caused discrepancies in the results of retinoscopy by various
practitioners. One of our pediatric ophthalmologists reports an
astigmatism of 1.25 diopters. Is this the same as a "corneal
irregularity?" Could either account for variations of 4 1/2 to 6 1/2
diopters in the prescription?
Answer:
1.25D of corneal irregularity should not amount to more than 1.25 D of power
in the overall prescription. However, the question is, who is actually
correct, the ped. MD, or the others. Retinoscopy on an infant can be dicey
at times. I would believe whoever did the retinoscopy with the infant's eyes
dilated. Those are usually the most stable readings. If indeed the corneal
irregularity is only 1.25 D, it won't be anything to worry about as long as
it's stable. It may change somewhat until she heals from the lens removal
procedure.
To answer another question, corneal irregularity does not necessarily equal
the amount of astigmatism, especially if your child has a problem with her
crystalline lenses, which I am assuming have been removed at this point.
