One of the changes that the name does not imply is that the retina (the part of the eye that processes light and sends it to the brain) may also be altered either in larger or microscopic amounts called retinal dysplasia.
Usually, PFVS is found in one eye that is somewhat smaller than the better eye and has a white pupil reflex and elongated ciliary processes. This set of findings does not tell the examiner whether retinal dysplasia is present or not. In some eyes the stalk of persistent fetal vessels may not opacify the visual axis of the lens (the part light rays pass through the lens giving best vision). This stalk can pull on the retina and disturb it as well as pull on the lens causing it to be poorly shaped (posterior lenticonus). This child usually does not have the white pupil and is often diagnosed at a later age.
In our experience, ultrasound, visual evoked potential response or electroretinography testing are not reliable in answering that question. At this time there are no other known systemic problems associated with PFVS. At this time no genetic mutations have been associated with the typical unilateral PFVS. About 10% of infants affected by PFVS have both eyes involved. These children more frequently have retinal dysplasia. Bilateral PFVS is also not associated with systemic changes. There is however a disease that can be indistinguishable from bilateral PFVS with extensive retinal dysplasia called Norrie’s disease. In this process the child may be affected with hearing loss or other central nervous system problems. Genetic testing is available for Norrie’s disease. As with many diseases known to be under genetic control, there may be several mutations. Norrie’s disease testing will confirm the diagnosis in 80% of the cases, leaving 20% of children where a mutation cannot be found, but clinical examination confirms Norrie’s disease. See Norrie's website at: http://www.norriedisease.org/
 Click image for larger view | Therapy for PFVS is surgical, usually with removal of the lens and persistent vascular stalk tissue. It can accomplish several things. It may reduce the risk of glaucoma (high pressure in the eye) and usually clears the opaque tissue out of the eye allowing light to reach the retina. It also can relieve pulling or distortion of the retina. The retina now being seen allows the physician to form an opinion as to the amount or absence of retinal dysplasia. In the past, we felt that the clinical exam could tell all we needed about retinal dysplasia, but now with the availability of flourescein angiography and OCT testing in infants under anesthesia, we can be much more accurate about microscopic retinal dysplasia. |
If the eye has no retinal dysplasia, there still is a great challenge to overcome occlusive amblyopia (the eye doesn’t want to function because messages were not sent to the brain during the early formative months). This can often be helped by contact lenses and patching the stronger eye. This should only be done with the advice of an ophthalmologist.
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