Now, to answer your question about testing for a unilateral case of Persistent Hyperplastic Primary Vitreous (PHPV) also called Persistent Fetal Vasculature Syndrome (PFVS)
This is a great question for two reasons:
1. I have found that about 20% of cases diagnosed with unilateral PHPV really have asymmetric bilateral disease. Typically it was Familial Exudative Vitreoretinopathy (FEVR). Therefore, I like to see a fluorescein angiogram of the periphery in both eyes. That requires an exam asleep. Often if the contralateral eye has significant ischemia I will treat it with laser. this is especially an important exercise if the PHPV (PFVS) is severe and the vision is reduced. This is an example of a unilateral PHPV diagnosis. A lovely photograph that shows truncated vessel growth quire characteristic of FEVR
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| Figure shows the findings of FEVR in the second eye of a child diagnosed with unilateral PHPV (PFVS) |
2. There are cases of FEVR that are unilateral, I would say not really that uncommon (about 10% of FEVR). However, among FEVR appearance cases only 10% could be confused with PHPV (PFVS). So the combination is pretty rare. Unfortunately the genetic testing is helpful only if positive, the confidence in a negative test is not there. Again, I like a fluorescein angiogram, but here my differentiation between unilateral PFVS (PHPV) and unilateral FEVR is still in the range of a hypothesis.
Of course the parents could get angiograms with good peripheral shots (not an easy task with typical fundus cameras) If there is a positive finding in the parents then the diagnosis is easy.
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