Persistent Fetal Vasculature or PFV is a developmental disorder that occurs at birth. In utero, the eye is built by the body using different structures – called stalks. In a typical child, the stalk will regress or wither away when it is done building the eye. In people with PFV, the stalk fails to regress causing structural abnormalities that usually lead to impairment in their vision (ASRS). In most cases, PFV will only affect one eye.
When looking at the eye, you will first see the cornea, followed by the Pupil, Iris and lens. But, the structure doctors look at first when dealing with a PFV case is the Retina. The retina is a thin layer of nerve tissue that is very light-sensitive that sits at the back of the eye. When a person sees light, the light enters the eye through the Iris and heads to the back of the eye where the light is processed into images which are focused and reported up to the brain, producing sight. Since the connecting the retina to the front of the eye never retreated in people presenting with PFV, the light is unable to filter properly through the Iris and its trip to the retina is disrupted. This causes poor to no vision in these individuals. This disorder usually does not progress after birth but as the eye continues to grow, the stalk and its components will not grow with it. As the stalk holds back other structures of the eye, it may cause other issues moving forward. The stalk may cause the retina to detach or the person’s eye to develop cataracts.
As you can see from many discovery stories on our blog, diagnosis of PFV is hard to come by. Some are lucky enough to spot it at birth but in others, it may present itself in other ways that lead to misdiagnosis. For example, PFV can present itself as the child being cross eyed (Stabismus), having abnormal eye movements (nystagmus) and as having a lazy eye (amblyopia) (ASRS). In many people with PFV, the affected eye will appear smaller than the other, however this isn’t the case for everyone. When a doctor believes the person may have PFV, they will look at the back of the eye to see if the stalk is present. Ultrasounds or MRI scans may be required to rule out other disease like Retinoblastoma – a rare tumor that may present itself on the back of the eye.
When Retinoblastoma is ruled out, the doctor may suggest surgery to remove the lens, remove the stalk and in some cases, reattach the retina. The surgery may not completely restore the childs’ vision to a state of “normal” but, without the stalk holding back the structures of the eye, the function of the eye can be improved and the affected eye may grow at a typical rate post surgery (ASRS).
For most children and families, post surgery starts an entirely new journey. A contact lens is usually prescribed to children who had their lens removed during surgery. They may also get glasses to use instead of or in addition to the contact lens. Soon after surgery, your child may begin patching therapy to help with their strabismus or amblyopia.
Unfortunately, peer reviewed studies of people with PFV are far and few between. When you do a general search of PFV, you will be directed to articles published that are full are very medical terms with a lot of conjecture and not many reliable numbers. The truth is, PFV is rare and doctors simply have not had the opportunity to study this disorder to its fullest potential. Until more research is done, we will continue to share what we have learned from these various medical journals and will continue to hope for more research moving forward!