Persistent hyperplastic primary vitreus (PHPV) is a congenital and hereditary eye disease. The disease is caused by an embryonic developmental disorder that causes the embryonic vitreous to persist and become hyperplastic. Treatment options usually correspond to surgery.
What is persistent hyperplastic primary vitreous?
The corpus vitreum is also known as the vitreous body. It is a gelatinous and translucent structure between the lens and retina. With its flexible shape, the vitreous maintains its pressure on the surrounding structures. The anatomical structure embraces a fine fibrous network that serves as a storage site for the humor vitreus. The vitreous can be affected by various diseases. One of them is PHPV, persistent hyperplastic primary vitreus. This congenital malformation is a disease from the group of rare congenital disorders. Two variants of the disease exist: an anterior variant and a posterior variant. The anterior variant is more common. Persistent hyperplastic primary vitreus (PHPV) is sometimes referred to by the synonymous term persistent fetal vascular structures (PFVS). Another synonym in the clinical literature is the term PHPV syndrome. The congenital disorder manifests in the neonatal period. The prevalence of the disorder is not known in detail.
Causes
During the embryonic period, the primary vitreous develops. This structure includes the hyaloid artery system in addition to the tunica vasculosa lentis. The primary vitreous does not persist but regresses. In patients with persistent hyperplastic primary vitreous, there is no regression of the embryonic primary vitreous. Thus, PHPV is an embryonic developmental disorder. In the anterior variant, the retained portion develops into a sheet of connective tissue. Thus, this variant is associated with hyperplasia. In the embryonic period, the retina of the eyes forms from the neural tube. The eye lens epithelium is formed from the surface ectoderm. The connective tissue of the eyes, for example, is formed from the mesoderm. Embryonic developmental disorders of the eyes may be favored by chemical noxae, ionizing radiation, or infections. In persistent hyperplastic primary vitreus, the primary cause is a genetic predisposition. Inheritance is X-linked, autosomal dominant, or autosomal recessive.
or autosomal recessive. Affected males inherit the disorder to all daughters, with daughters being carriers and passing on the disorder with a 50 percent probability.
Symptoms, complaints, and signs
The first symptoms of persistent hyperplastic primary vitreus (PHPV) appear no later than early childhood. A connective tissue plate has formed during embryonic development. The whitish plate lies immediately behind the pupil. This makes the patient’s pupil appear whitish, which is also known as leukocoria or amaurotic cat’s eye. The changes in the pupil area result in changes in the lens. Fatty tissue is deposited and cartilage forms around the lens. Multiple scarring processes occur. The ciliary villi become distorted and appear in the area of the pupil. Since the retina is also affected, this anterior variant of the disease may result in uncharacteristic visual loss, the severity of which depends on the extent of retinal detachment. At times, cataracta membranacea is seen, turning the lens into a cloudy membrane. All fatty tissue neoplasms in the lens area are called pseudophakia lipomatosa. The eye is retarded in growth as it progresses. Often, additional aqueous humor outflow disorders are present, which may result in hydrophthalmos. Hydrophthalmos may develop into glaucoma with blindness.
Diagnosis and course of the disease
Patients with persistent hyperplastic primary vitreous usually receive their diagnosis in infancy. In addition to history and family history, gold-standard ultrasound examinations play a role in verifying PHPV. In some cases, visual diagnosis may already suggest the disease, for example in the case of a clearly visible connective tissue plate in front of the lens.However, in this case, other malformations as well as tumors such as retinoblastoma must be considered for differential diagnosis. The prognosis for patients with PHPV depends on retinal involvement.
Complications
For the treatment of persistent hyperplastic primary vitreous (PHPV), there is currently no therapy that shows promise. There is always a loss of visual acuity, or visual loss. However, in case of complications, immediate surgical treatment should be performed. More common complications are retinal detachment and retinal dysplasia. Without treatment, retinal detachment can lead to blindness. In many cases, however, it progresses without symptoms, so it is often not recognized right away. Sometimes, however, dots, spots, colors or flashes of light are perceived. If a so-called sinking rain (sooty rain) occurs, a hemorrhage takes place in the vitreous body, which increases the risk of rapid blindness. In these cases, the entire vitreous body must be replaced. Other symptoms of retinal detachment may include visual field loss or distorted perception of the environment. A further complication of PHPV is the so-called retinal dysplasia. In this case, the retina is malformed. Affected individuals see flashes of light and flickering spots. In the worst case, retinal dysplasia also leads to retinal detachment. In PHPV, there is also microphthalmos. This is an eye that is too small. This fact, in turn, can lead to obstruction of aqueous humor outflow. Thus, a further complication of PHPV can be hydrophthalmos with increased intraocular pressure (glaucoma), which without treatment is often the cause of blindness.
When should you see a doctor?
This disease must be treated by a doctor in any case. It does not come to a self-healing and also not to an improvement of the complaints. The discomfort can only be removed by surgery, so a visit to a doctor is always necessary. The doctor should be consulted when there is discomfort in the eyes, for example, when the affected person has severe visual impairment or when the retina detaches. The visual complaints can also occur at a later age. In the worst case, the patient suffers complete blindness. Therefore, if visual complaints suddenly appear for no particular reason and do not disappear on their own, a doctor should always be consulted. As a rule, the disease can be diagnosed by an ophthalmologist, although the treatment itself usually involves an inpatient stay in a hospital. Life expectancy is not usually reduced by this disease.
Treatment and therapy
Causative therapy is not available for patients with PHPV. The developmental disorder has already occurred and is also genetic. Thus, causative therapies remain out of the question as long as gene therapy treatment does not achieve regulatory approval. The visual loss that has occurred in the patients cannot be treated promisingly. Symptomatic treatment options are also limited. The focus of therapy is the prevention of complications. To avoid complications, invasive steps such as surgery may be necessary. In addition, some scientists advocate that surgical interventions may be able to preserve the current state of visual acuity. If this is the case, surgery would automatically prevent complete loss of visual acuity. Surgery is also indicated in other contexts. Even when complete loss of visual acuity has already occurred in one eye, invasive procedures improve the patient’s situation. As a rule, the eye can be preserved by surgical intervention. Thus, on the cosmetic side, there is not too much impairment. Since the face plays the role of a calling card in interpersonal relationships, preservation of an eye that has even become completely nonfunctional is always preferable to complete removal.
Aftercare
Because persistent hyperplastic primary vitreous (PHPV) cannot be treated in most cases, there is often no follow-up care for patients. Patients must learn to cope with reduced vision. The exception is when surgery is performed on the vitreous to at least partially preserve vision.After the surgical procedure, patients are prescribed appointments for follow-up examinations by the ophthalmologist. At the follow-up appointments, the doctor checks how far the operated vitreous has healed again and whether there may have been any complications from the surgery. In addition, patients must take eye drops regularly to prevent the operated eye from drying out. The deterioration of vision can become a psychological burden if the PHPV occurs very late in childhood. In such cases, it is recommended that parents seek therapeutic help for their children. In therapy, children can learn how to cope with their daily lives even with reduced vision. But parents and family members also learn how to support the child. A nearly normal life is possible in very many cases despite the vitreous malformation.
Outlook and prognosis
Because the eye condition called persistent hyperplastic primary vitreous – or PHPV for short – is hereditary and congenital, this embryonic developmental disorder can only be corrected later by surgery. In PHPV, the vitreous body of the eye is affected. This disorder is relatively rare. However, it occurs in two different variants. The anterior variant of the PHPV syndrome is the one that occurs more frequently. Its effects become apparent in infancy or in the early years of childhood. The prognosis of PHV syndrome depends on the severity of vitreous damage and the course or treatment initiated. An important question regarding the outlook is also whether and to what extent the retina is involved. It is problematic that there are no other treatment options so far except surgical therapy. Surgery is usually the treatment of choice for complications such as retinal detachment, or retinal dysplasia. Such operations on the eye represent emergency measures against imminent blindness. Sight can also be lost due to glaucoma. Preventing this is the goal of surgery. If surgical preventive measures are applied, the actual condition can be maintained for a long time. In the case of persistent hyperplastic primary vitreous disease, the medical community is hopeful that gene therapy may be an eventual treatment option. This could potentially improve prognosis significantly.
Prevention
Persistent hyperplastic primary vitreus (PHPV) can be prevented exclusively by genetic counseling during the family planning phase. Affected men, in particular, should at least be aware that they are passing the disease on to their children.
What you can do yourself
Persistent hyperplastic primary vitreus (PHPV) is a condition that can only be cured by medical treatment. In everyday life, PHPV is manifested by discomfort in the eye, for example, by a decrease in vision or detachment of the retina. To avoid complete blindness, it is important to pay attention to these signs. The medical examination will show whether it is really the disease and what treatment options are available. By following the doctor’s recommendations, difficulties can be prevented or at least postponed. Often the best solution is surgery. PHPV is a hereditary disease, so it is advisable to find out exactly about it when planning a family. Often children are already affected by the disease, therefore parents should inform themselves early on about the surgical measures that are possible. For everyday life itself, there is not much advice on how to deal with PHPV. From a certain degree of the disease, those affected find it difficult to read or see other things. They can then take it easy on their eyes, but resting in everyday life only serves to alleviate the situation and does not improve it.
