What are these conditions?
Vascular retinopathies are eye conditions that result from poor blood supply to the eyes. The five types of vascular retinopathy are cental retinal vein occlusion, diabetic retinopathy, hypertensive retinopathy, sickle cell retinopathy, and central retinal artery occlusion.
What causes them?
When one of the arteries that supplies blood to the retina become, blocked, blood flow diminishes. This damages the eye and causes vision problems.
Causes of central retinal vein occlusion include external compression of the retinal vein, injury, diabetes, blood clots, granulomatous diseases, infections, glaucoma, and atherosclerosis. This form of vascular retinopathy is most prevalent in elderly people.
Diabetic retinopathy results from juvenile or adult diabetes. Microcirculatory changes occur more rapidly when diabetes is poorly controlled. About 75% of people with juvenile diabetes develop retinopathy within 20 years of the disease’s onset. In adults with diabetes, incidence increases with the duration of diabetes. This condition is a leading cause of acquired adult blindness.
Hypertensive retinopathy results from prolonged high blood pressure, producing retinal vasospasm and consequent damage and narrowing of retinal blood vessels.
Sickle cell retinopathy results from the impaired ability of sickled cells to pass through the tiny capillary blood vessels, producing obstructions. This results in microaneurysms, chorioretinal tissue death, and retinal detachment.
Central retinal artery occlusion may have an unknown cause or may result from embolism, atherosclerosis, infection, or conditions that slow the blood flow, such as temporal arteritis, a narrowed carotid artery, and heart failure. This rare type of retinopathy occurs in one eye and affects elderly people.
What are their symptoms?
Central retinal vein occlusion reduces vision, allowing perception of only hand movement and light. This condition is painless, except when it results in secondary neovascular glaucoma (uncontrolled proliferation of weak blood vessels). The prognosis is poor – 5 % to 20% of people with this type of vascular retinopathy develop secondary glaucoma within 4 months.
Nonproliferative diabetic retinopathy produces changes in the lining of the retinal blood vessels that cause the vessels to leak plasma or fatty substances, which decrease or block blood flow within the retina. This disorder may also produce microaneurysms and small hemorrhages. Although some people with nonproliferative retinopathy lack symptoms, others have significant loss of central visual acuity (necessary for reading and driving) and diminished night vision.
Proliferative diabetic retinopathy causes fragile new blood vessels on the disk and elsewhere. These vessels can grow into the vitreous and then rupture, causing sudden vision loss. Scar tissue that may form along the new blood vessels can pull on the retina, causing macular distortion and even retinal detachment.
Symptoms of hypertensive retinopathy depend on the location of retinopathy. For example, mild visual disturbances, such as blurred vision, result from retinopathy located near the macula (a spot near the center of the retina concerned with visual acuity). Without treatment, 50% of people become blind within 5 years. With treatment, the prognosis varies with the severity of the disorder. Severe, prolonged disease eventually causes blindness; mild, prolonged disease causes visual defects.
Central retinal artery occlusion causes sudden, painless vision loss (partial or complete) in one eye. This condition typically causes permanent blindness. However, some people experience spontaneous resolution within hours and regain partial vision.
How are they diagnosed?
Appropriate diagnostic tests depend on the type of vascular retinopathy. Evaluation includes determination of visual acuity and ophthalmoscopic examination.
How Vascular Retinopathies are treated?
Vascular Retinopathies teatment approaches depend on the type of retinopathy. Therapy for central retinal vein occlusion may include aspirin, which acts as a mild anticoagulant. Laser photocoagulation can reduce the risk of glaucoma for some people.
Treatment of nonproliferative diabetic retinopathy is prophylactic.
Careful control of blood sugar levels during the first 5 years of the disease may delay its onset or reduce its severity. For people with early symptoms of microaneurysms, therapy includes frequent eye exams (3 to 4 times a year) to monitor their condition. For children with diabetes, therapy includes an annual eye exam by an ophthalmologist.
The best treatment for proliferative diabetic retinopathy is laser photocoagulation, which cauterizes the leaking blood vessels. Despite treatment, neovascularization doesn’t always regress and vitreous hemorrhage, with or without retinal detachment, may follow. If the blood isn’t absorbed in 3 to 6 months, vitrectomy may restore partial vision.
Treatment of hypertensive retinopathy includes control of blood pressure with appropriate drugs, diet, and exercise.
No particular treatment has been shown to control central retinal artery occlusion. To lower intraocular pressure, therapy includes Diamox, eyeball massage and, possibly, anterior chamber paracentesis. Another treatment, inhalation of carbogen (95% oxygen and 5% carbon dioxide), improves retinal oxygenation.