If your eyesight is getting weak and you don’t know the cause, there can be many reasons. In general, as we age, you can expect to have some issues with your eyes as with other senses. If you live long enough, everyone will experience at least one eye condition in their lifetime that will require appropriate care.
Loss of vision can occur suddenly, but most often, the warning signs of vision loss are gradual. You may not even notice the loss until you have trouble focusing or other complaints. Then you will be compelled to go for an overdue eye exam. That’s when your ophthalmologist may find you have a serious eye disease, such as AMD (Age-related macular degeneration), glaucoma, or diabetic retinopathy.
This is why a comprehensive eye exam should be had by the age of 40 at least. Even though you don’t have any major symptoms, you may have a significant problem. (Note that an annual comprehensive eye exam is recommended for every age.)
Dry AMD (Age-related macular degeneration)
Dry AMD is common, accounting for about 90% of cases. It is a slow, painless thinning of the retina. As the retina’s delicate tissue breaks down, the cells needed for vision stop working well; as a result, vision is blurred.
Dry AMD can progress over time to wet AMD causing significant vision loss. Wet AMD causes vision loss when abnormal blood vessels grow in the eye and leak below the macular, the center part of the retina. Regular eye exams can help prevent or delay this progression.
The retina contains millions of photoreceptors, rod, and cone cells that pick-up light and transmit signals to the brain for processing images. Nourishing the photoreceptors is a layer of cells called the retinal pigment, epithelium, or RPE. AMD damages the RPE starving the photoreceptors of nourishment and causing vision loss.
Dry AMD is characterized by the presence of “drusen,” small white or yellowish deposits under the retina. The drusen build up over time and push through the eye tissue layers above, disrupting the photoreceptor cell and causing blind spots in central vision. You will not generally notice the presence of drusen. Your eye doctor should be able to see them during an eye exam. Signs of dry AMD include a slight blurring of vision and a need for brighter light when reading. Blind or blank spots in the center of vision and an enlarging of these spots distort visual images over time. Loss of contrast may also be noted.
Because dry AMD is a slowly progressing and painless condition, signs of AMD can often go unnoticed until the later, more severe stage of the disease. Also, the eyes are adaptable, meaning that one eye can compensate for vision loss in the other eye. This compensation makes it even more difficult to notice signs of dry AMD. Regular exams are critical as your ophthalmologist can see early signs of the disease during an eye exam.
Your doctor will look for the physical signs of dry AMD:
- The presence of drusen
- Under or over pigmentation
- Coloring of the retina
- Atrophy or wasting away of the retinal pigment
There is no curative treatment for dry AMD. Instead, it is managed through regular monitoring of vision, risk modification, and the use of low vision aids. By taking steps to prevent or slow its progression, your retinal specialist can prevent a more severe form of the disease.
Glaucoma
A leading cause of blindness for patients older than 60 years old, glaucoma has no early symptoms. Even though they have it, only about half of the people know they have glaucoma. That is why it’s important to have a glaucoma test.
Glaucoma is a neurodegenerative condition that affects the eye and is associated with increased intraocular pressure (IOP). When left untreated, patients may gradually experience visual field loss and even lose their sight completely.
The increased intraocular pressure on the optic nerve occurs when the fluid in your eye does not drain properly. As fluid pressure gradually builds up in your eye it damages the optic nerve.
Because chronic forms of glaucoma are painless, measurable visual-field defects do not develop at an early stage of glaucoma, and defects generally don’t occur simultaneously in both visual fields. Self-detection of glaucoma by affected individuals usually occurs at a late stage of the disease.
The primary way of detecting glaucoma is by examining the optic nerve head and retinal nerve fiber layer. With early treatment, blindness from glaucoma can often be prevented. Treating it doesn’t restore any vision you may have lost, but it can help save your remaining site.
The only proven and generally accepted treatment to reduce the risk of further progression of glaucoma is to lower intraocular pressure. Reduction of intraocular pressure is achieved by drug treatment, laser therapy, or surgery. The goal is to reduce the intraocular pressure towards an individual target level at which further progression of glaucomatous optic nerve damage is unlikely.
The aim is usually for a reduction in the intraocular pressure of 20–50%. The greater the pre-existing optic-nerve damage and the more risk factors present, the lower the target pressure is set. The target intraocular pressure is re-analyzed periodically by assessing whether the optic-nerve damage is stable or has progressed.
Diabetic Retinopathy
Diabetic retinopathy is a common diabetic eye disease caused by changes in the retinal cells. It affects up to 80% of all patients who have had diabetes for ten years or more.
Blood vessels travel through the optic nerve, through the retina, and exit the back of the eye through the middle of the optic nerve. Over time high sugar levels can damage the blood vessels. As a result, they can leak blood or other fluids, causing swelling and damage to the retina.
In the early stages of diabetic retinopathy, there are no symptoms or very mild symptoms that may go unnoticed. Usually, both eyes are affected by diabetic retinopathy.
As diabetic retinopathy progresses, the following signs and symptoms may occur:
- Eye floaters in your field of vision.
- Difficulty seeing well at night.
- Pain or pressure in one eye or both eyes.
It’s crucial to find out if you have diabetic retinopathy early and have your retinal specialist treat the disease. If left untreated, it can eventually lead to blindness. Timely diagnosis and regular check-ups, and optimal control of blood sugar through diet, exercise, and medication are of utmost importance to effectively manage diabetic retinopathy.
