My wife and I have a daughter that may need surgery for a cataract. The retina is involved with some scarring. My daughter is 10 months. The question of whether she should the surgery NOW because of visual neurodevelopment. Can VEP be used to diagnose nerve compromise?
This is important because if the nerve is not being compromised, we ,may be able to wait and do the surgery later when she can tell us what she sees.
If it is compromising the nerve then she should have the surgery now. Can that or any other test look at and describe neurologic status and then be done serially if normal now
Your questions are good ones indeed, but let me begin by clarifying a few clinical issues before we tackle your specific questions about testing. When an infant has PFV (persistent fetal vasculature, for those less familiar with the abbreviation), there are three things that really need to be considered when deciding about whether or not surgery is recommended:
So, assuming that the vision pathway IS compromised, and the central part of the retina (the macula) DOES look fairly normal, and the surgery IS technically feasible, then it would make sense to proceed with the surgery as soon as possible, because the older a baby gets, the less likely it is that the child will indeed be able to use the eye (from an amblyopia or visual deprivation point of view).
Now, finally, to answer your other questions: VEP (visual evoked potential) testing is useful when we do not know how intact the pathway of vision is from the eye to the brain. In the case of a baby with PFV, there is no particular benefit to doing this test. It is very difficult to detect small amounts of difference in vision between eyes with this type of testing, and it is more useful for assessing vision processing in cases such as cortical or neurologic visual impairment. The optic nerve is not the problem in most cases of PFV. If there does happen to be an abnormality of the optic nerve that co-exists with PFV, it still makes sense to try to clear the vision pathway to put the eye in the best focus possible, so that whatever messages are transmitted from the optic nerve to the brain from that eye will be of the best possible quality.
I hope this helps in your thought process. The most important thing to do, as in any complex clinical situation, is to work closely with an expert pediatric ophthalmologist, so that together you can formulate the best possible management strategy for your precious baby.
Good luck with your decision and your baby,
Sharon F. Freedman MD
Scientific Advisory Board