You might think of an eye exam as something you only need if your vision changes. However, good vision isn’t the only indicator of eye health. Many eye conditions associated with vision loss don’t cause any symptoms in the early stages.
Glaucoma is a disease of the optic nerve, which is the part of the eye that sends visual signals to the brain. Injury to the optic nerve may occur when the eye pressure is too high, or blood flow is impaired.
You may experience gradual vision loss as the damage progresses, starting with your peripheral (side) vision. This process is painless and has no symptoms in the earlier stages, which is why glaucoma is the “silent thief of sight.” Less than 50% of people who have glaucoma are aware of their diagnosis! If left untreated, glaucoma causes severe vision loss or blindness.
Several genes that influence glaucoma have been identified, so any family history is important to know. There are also other risk factors, such as:
- Older age
- Previous ocular injury or surgery
- High myopia (nearsightedness)
Glaucoma is the leading cause of irreversible blindness in the world. Any vision loss is permanent, so early detection and treatment are crucial. Glaucoma treatments work to slow the progression of the disease by lowering eye pressure. Therapies include:
- Medicated eye drops
- Laser treatment
- Minimally invasive glaucoma surgery
- Glaucoma implant surgery
Age-related Macular Degeneration (AMD)
As the name suggests, AMD typically affects people over 55 years of age and is another leading cause of blindness. Surveys predict that global cases of AMD will increase from 196 million to 288 million within the next 20 years. Your risk for AMD depends on a combination of age, genetics, sun exposure, heart disease, high cholesterol, smoking, and other factors.
The macula is the central portion of your retina (the light-sensing tissue inside the eye). Although just a few millimeters in size, the macula is responsible for seeing fine details, color vision, and central vision.
AMD is a complex disease that causes loss of central vision. However, early stages of AMD are symptomless or have milder symptoms, such as:
- Blurry vision
- Blind spots
- Distortions in the vision (straight lines appear wavy or broken)
- Color vision changes (dullness of color)
- Difficulty reading or driving
- Poor night vision
Your risk for vision loss depends on the stage of AMD:
- Dry AMD is the most common type of AMD and is slower to progress. In this stage, your eye doctor may detect drusen, which are yellow deposits of debris within the macula. Some drusen do not cause vision problems and do not require treatment. However, a larger size and number of drusen indicate a higher risk for advanced disease.
- Geographic atrophy (GA) is an advanced form of dry AMD. Retinal cells in the macula begin to die, causing thinning of the retina in that area. Significant vision loss may occur in this stage if the GA spreads into the fovea (center of the macula).
- Wet AMD is an advanced stage that causes the most severe vision loss. Approximately 10% of people with AMD develop wet AMD. This form is also called neovascular AMD because abnormal blood vessels grow and bleed into the retina. Rapid vision changes may occur as a result of leaky blood vessels.
Current treatments mainly target wet AMD, which include eye injections of anti-vascular endothelial growth factor (anti-VEGF). There is no specific treatment for dry AMD, although eye vitamins are typically prescribed. Soon, medical therapy for GA may become available. As with glaucoma, AMD is irreversible. Early detection is essential to preserving vision.
Diabetic Retinopathy (DR)
DR affects over a third of adults who have diabetes. High blood sugar affects the blood vessels in the retina, causing them to become weak and prone to leakage. DR may be asymptomatic initially but can become vision-threatening if it progresses. The primary stages of DR are:
- Nonproliferative DR can be mild, moderate, or severe. Depending on the stage, your eye doctor may detect tiny protrusions of blood vessel walls, leakage of blood or fluid, and decreased blood flow in the retina. In nonproliferative DR, many people remain asymptomatic.
- Proliferative DR occurs after severe nonproliferative DR. As the retina becomes deprived of a normal blood supply, it grows abnormal blood vessels in response. These new vessels are leakier than normal vessels and may cause vision changes. Symptoms include blurry vision, spots in the vision, color vision changes, and decreased side vision.
Other complications of DR include:
- Diabetic macular edema occurs when fluid leaks underneath the macula, affecting the central vision. You may notice distortions in your vision at this stage. Nearly a quarter of people with DR have diabetic macular edema.
- Vitreous hemorrhage may develop in people with proliferative DR. When the abnormal blood vessels rupture, they can bleed into the vitreous (clear gel filling the cavity of the eyeball).
- Retinal detachment is also a risk in people with proliferative DR. Abnormal blood vessels develop scar tissue, which then contract and pull on the retina, causing it to detach.
Some types of DR require treatment with laser, anti-VEGF or steroid injections, or retinal surgery. If left untreated, DR can ultimately result in blindness. Another key component is controlling your blood sugar. If the diabetes is not well-managed, DR can continue to progress.
Retinal Tumors and Other Lesions
Tumors in the retina can be benign or malignant (cancerous). Benign tumors typically do not cause any symptoms and can be monitored. Malignant tumors require immediate medical attention as they can be threatening to the eye or even life-threatening if the cancer spreads.
Types of retinal tumors and lesions include:
- Choroidal nevus is a common, benign retinal tumor that appears as a pigmented, well-defined area in the retina. Choroidal nevi are found in approximately 5% of adults. Sometimes, a nevus is called an eye freckle. These spots do not need treatment but are typically monitored.
- Congenital hypertrophy of the retinal pigment epithelium (CHRPE) is a darkly pigmented spot in the retina that is present at birth in about 1% of people. These lesions do not cause symptoms and do not require treatment. However, in atypical cases, CHRPE is associated with familial adenomatous polyposis, a type of colon cancer.
- Choroidal melanoma develops from a choroidal nevus in approximately 1 out of 9,000 people. Although this cancer is rare, it can spread throughout the body and become life-threatening. These tumors are treated with surgery, radiation therapy, and lasers.
Early Detection Is Vital
This article covers some eye diseases that are “silent” but can become vision- or life-threatening. There are many other eye conditions that your eye doctor can diagnose and treat. With early detection, many diseases can be prevented or treated. The best way to ensure optimal vision and eye health is to see your eye doctor for annual eye exams. Contact our practice to schedule your eye exam today!