Clear vision is what allows us to experience the world in vivid detail and navigate our daily lives with ease. But there are hundreds of eye diseases, from common conditions such as cataracts and glaucoma to more complex ones like macular degeneration, that can sabotage our eyesight when not detected and treated early.
Here’s what to know about the delicate, complex structures of the eye, the types of eye diseases that are most common and the best possible treatments for preserving both eye health and vision.
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What Are Eye Diseases?
Eye diseases and eye conditions can impact any of the many parts of the human eye:
— The pupil: the black opening in the middle of the eye that lets light into the eye
— The iris: the colored part of the eye that helps regulate the size of the pupil and thus how much light enters the eye
— The cornea: the outer sheath that covers the pupil and iris and helps focus light onto the retina at the back of the eyeball
— The lens: a sheath of tissue that sits behind the iris and further focuses light and visual information onto the retina
— The sclera: the white of the eye
— The conjunctiva: a thin film that covers the white part of the eye and encases the back of the eye
— The retina: a thin film at the back of the eye that organizes visual information and transmits it to the optic nerve
— The macula: a point in the center of the retina
— The optic nerve: a nerve that runs from the back of the eye to the brain and transmits visual information to be interpreted by the brain
There are other components inside the eye as well, including blood vessels, fluid and other structures that help keep the eyeball functioning the way it should.
When one or more of these components becomes diseased, injured or impaired, you may develop one of the eye diseases below.
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Diabetes-Related Eye Problems
The Centers for Disease Control and Prevention reports that in 2021, 38.4 million people in the U.S. had diabetes. Diabetes develops when your levels of blood glucose — the amount of sugar circulating in the blood — are consistently too high. This occurs when your body can’t produce enough insulin to regulate these levels or isn’t able to use the insulin your body makes appropriately.
While there are different types of diabetes, all forms can threaten eye health. And, because diabetes is common, related eye complications are common as well.
Diabetic retinopathy
About 1 in 3 people with diabetes also has diabetic retinopathy, “making it a major cause of blindness in working-age adults,” says Dr. Caleb Ng, an ophthalmologist with Providence St. Jude Medical Center in Fullerton, California.
The retina is a thin sheath of tissue that adheres to the inside wall of the back of the eyeball. It contains millions of light-sensitive cells called rods and cones that receive and organize visual information and send it on to the optic nerve for processing. These structures and the tiny blood vessels that feed the region can become damaged over time because of high blood sugar levels related to diabetes.
Diabetic retinopathy is more likely to develop in people who’ve had diabetes for a long time and in those whose blood sugar has not been well controlled. It usually develops in both eyes with the following symptoms:
— Spots or dark floaters
— Blurry or hazy vision
— Impaired color vision
— Vision loss
If left untreated, diabetic retinopathy can result in:
— Bleeding in the eye
— Retinal detachment
— Glaucoma
— Blindness
For these reasons, it’s important to stay on top of your eye health when you have diabetes.
“You should have a baseline screening when you’re first diagnosed with diabetes,” says Dr. Dianna L. Seldomridge, clinical spokesperson for the American Academy of Ophthalmology and an ophthalmologist at the Duke Eye Center of Winston-Salem in North Carolina.
Treatments are geared toward the prevention of vision loss, she adds, because “once you lose vision from diabetes, it’s hard to recover it.”
Controlling your diabetes, managing blood pressure and making necessary lifestyle changes are critical to preventing vision loss. Seldomridge recommends keeping your hemoglobin A1C — a measure of blood sugar levels over time — at or below 6.5.
You should also work to lower your blood pressure and cholesterol levels if these are high. Exercise and staying active can improve blood sugar and blood pressure. Regular checkups with an ophthalmologist can help spot early signs of diabetic eye disease.
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Age-Related Eye Diseases
Visual acuity and eye health can decline over time, and the older you are, the more likely you are to have an age-related eye disease or some vision loss. The most common age-related eye conditions include:
Cataracts
Cataracts are a common eye health problem that becomes increasingly prevalent as people enter their 60s and 70s, but it may occur at a younger age in people with certain risk factors, explains Dr. Mona Adeli, clinical assistant professor in the department of ophthalmology and visual sciences at the Ohio State University Wexner Medical Center in Columbus.
Cataracts develop “when proteins in the eye’s lens break down, causing cloudiness and blurred vision,” Ng adds.
This is often related to age, but it can also occur if the eye sustains trauma, which is why eye protection during high-risk activities is critical.
Initially, cataracts may not cause any symptoms, but as they progress, “people typically notice their vision become gradually blurrier,” Adeli explains. “Updating your glasses prescription can often help improve vision early on,” but eventually, as the lens becomes increasingly cloudy, it might feel like you’re peering through a window smeared with Vaseline.
Cataracts symptoms can include:
— Gradual or progressive decrease in vision
— Loss of vision correction with glasses
— Cloudy or blurry vision
— Double vision
— Loss of contrast and color sensitivity
— Poor night vision
Essentially, everyone will develop cataracts if they live long enough.
“We can’t completely avoid them, but not everyone needs to have cataract surgery to correct them,” , Seldomridge says.
Cataract surgery, the primary way to treat the condition, is one of the most common surgeries performed in the U.S. today, with a 98% success rate, according to Ng.
Making certain lifestyle chances can also help:
— Avoiding UV exposure (by wearing sunglasses)
— Controlling your diabetes if you have it
— Avoiding eye injury
— Avoiding taking steroid medications
Glaucoma
Glaucoma causes damage to the optic nerve, a bundle of more than 1 million nerve fibers that run from the back of the eye to the brain. These nerves transmit visual stimuli to the brain where it’s interpreted as sight.
In glaucoma, a buildup of fluid in the front part of the eye causes an increase in eye pressure that in turn causes nerve damage or neuropathy. Known as ocular hypertension, this increased pressure is different from high blood pressure in the rest of the body, Seldomridge notes.
If you’re African American or Hispanic, your risk of glaucoma is higher, Seldomridge adds. Diabetes, a history of eye injury, a family history of glaucoma and thinning of the cornea also increase risk.
Glaucoma symptoms may include:
— Intense eye pain
— Tunnel vision
— Severe headache
— Nausea and vomiting
— A sudden change or disturbance in vision
— Blurred vision
— Halos around lights
— Reddening of the eye
If you experience these symptoms, seek care right away. Untreated glaucoma is serious and can cause blindness. Eye drops, oral medication, laser surgery or a combination of these approaches can all be used to help reduce symptoms.
Symptoms may not be obvious until the disease is more advanced, but your ophthalmologist can evaluate you for glaucoma regularly with a routine test called a tension check.
“Early detection through regular eye pressure tests is critical since vision loss from glaucoma is irreversible,” Ng notes.
Age-related macular degeneration
Age-related macular degeneration, or AMD, causes deterioration of the macula, a section of tissue in the center of the retina. This leads to blurry vision or blind spots in the center of your field of vision.
“Typically, we don’t see macular degeneration before the age of 50 or so,” Seldomridge says.
Risk goes up with age and family history. Smoking, being overweight or obese and having high blood pressure are also risk factors.
Macular degeneration comes in two forms: wet and dry. About 90% of all cases of age-related macular degeneration are the dry form. In this type, the cells of the macula atrophy, leading to a buildup of drusen — a small pile of waste from the cells — on the retina. This typically results in progressive vision loss.
The wet form of the disease tends to cause blindness faster. It’s called wet because new blood vessels grow behind the retina. These vessels tend to be weak and allow blood and fluid to leak into the eye. It can also cause scar tissue to develop, leading to vision loss.
Macular degeneration symptoms include:
— A gradual, progressive decline in vision
— Distorted vision (for example, straight lines look wavy)
— Missing spots in the field of vision
— A need for more light to read
— Increased sensitivity to glare
Some medications can help with the wet form of the disease. They’re typically administered as an injection to the eye in a doctor’s office. Increasing your intake of vitamins that support vision, such as lutein, vitamin C and vitamin E, may also help particularly in the dry form of the disease.
Eye Infections
Infections from bacteria, viruses, fungi and other pathogens can impact several structures of the eye. While many tend to resolve quickly, eye infections can become very serious.
Conjunctivitis
Also known as pink eye, conjunctivitis refers to inflammation, swelling or infection of the conjunctiva, the transparent membrane that covers the white part of the eyeball.
Commonly caused by a viral or bacterial infection, conjunctivitis makes the white part of the eye appear red. It may also make the eye feel itchy or gritty, like there are tiny grains of sand between the eyeball and the eyelid.
A pink eye infection typically causes discharge that can form a crust while you sleep. This crust can make your eyelashes stick together and make it difficult to open your eye.
Although pink eye is often associated with kids, it can happen at any age.
“Whether you’re a child or an adult, most episodes of conjunctivitis are related to a virus,” Seldomridge adds.
This means the healing can’t be sped up. Viral infections typically need to run their course, and antibiotics are not an appropriate treatment.
When conjunctivitis is caused by bacteria, however, antibiotic eye drops may help.
“It’s a good idea if you have a conjunctivitis to be checked by an ophthalmologist to determine whether it’s viral or bacterial,” Seldomridge says.
Corneal diseases
The cornea is the dome-shaped, clear, outermost layer of the eye that covers the iris and the pupil. It’s useful for protecting the eye and focusing light onto the retina, helping you see.
The cornea contains no blood vessels; rather, the tissue receives its nutrients from tears and aqueous humor, which is fluid in the front part of the eye just behind the cornea. Blinking distributes tears across the cornea to keep it moist and help prevent infection.
Injuries, scratches and allergies
Injuries and scratches to the cornea, including from a bout of shingles in the eye, are common and can cause:
— Pain
— Sensitivity to light
— Reduced vision
— Redness or inflammation.
Seasonal allergies can also impact the cornea, causing redness, itchiness and a watery discharge.
Dry eye
Dry eye affects more than 16 million Americans, “with numbers rising due to increased screen time and environmental factors,” Ng says. Dry eye occurs when your eyes don’t produce enough tears or when tears evaporate too quickly.
Other dry eye causes include:
— Aging
— Contact lens use
— Certain medications
— Hormonal fluctuations related to perimenopause and menopause
Dry eye symptoms can include:
— Burning
— Redness
— A gritty sensation
— Light sensitivity
— Blurred vision
If dry eye progresses and the cornea becomes dry, that creates an opening for infection, so it’s important to keep the eyes well lubricated. Over-the-counter eye drops may help, but if the problem persists, you may need a prescription.
“Treatments range from artificial tears and prescription drops to lifestyle changes like blinking exercises and using humidifiers,” Ng adds.
Keratitis
If the cornea becomes too dry, a rare condition called keratitis can develop. This is an inflammation of the cornea that may also result from injury or wearing contact lenses too long.
Bacteria, viruses, fungi or parasites can also cause keratitis, which needs to be treated with medication and sometimes surgery.
Keratitis symptoms include:
— Eye redness
— Pain
— Excess tearing
— Blurred or decreased vision
— Sensitivity to light
— Feeling like something is in the eye
Corneal dystrophies
Corneal dystrophies can also develop when a buildup of material on the cornea causes loss of clarity. These conditions tend to be inherited and affect both eyes. They can take a variety of forms but tend to be less common than dry eye and injuries to the cornea.
Retinal Diseases
Although many cases of retinal problems are related to diabetes, injury and trauma, other factors can also cause an otherwise healthy person to develop retinal issues. Retinal diseases can take several forms.
Retinal tear or detachment
As we age, our tissues become more susceptible to deterioration, and with the retina, this can result in tears and detachment. Tears and detachments can result in blurry vision and blindness, but they may be correctable with surgery.
Epiretinal membrane
In some people, a very thin layer of scar tissue forms on the surface of the retina that impedes vision. You may not notice any symptoms of an ERM, and these issues are often found during routine eye exams or in the course of treating another problem.
Over time, these membranes can pull or pucker, which is why the condition is sometimes called macular pucker. This puckering can lead to vague visual distortion.
Macular hole
An actual hole can develop in the macula, which is the center of the retina. This can occur when the retina starts to detach as a result of age or after an injury to the eye.
Macular holes are a separate issue from macular degeneration, but the symptoms are similar, namely blurry or limited central vision. Injections or surgery may be required to repair the problem.
Other Eye Conditions
Other problems can develop in the eye from time to time that may require treatment. Common eye issues include:
Blocked tear ducts
Sometimes the tear ducts, which normally act as drains for tears, can become obstructed, leading the eyes to become watery and irritated.
Blocked ducts are common in newborns and tend to resolve on their own. In adults, they’re usually caused by an infection, an injury or a tumor.
Treatment depends on what’s causing the obstruction, but most of the time it’s fixable with gentle massage, warm compresses, antibiotics, a procedure called probing to widen the tear duct opening or, in severe cases, surgery.
Floaters
Floaters look like gray or black spots, strings or speckles drifting across your field of vision. They track with your vision and appear to dart away when you try looking directly at them.
Floaters are often caused by tiny fibers within the vitreous liquid inside the eye that clump together and throw shadows on your retina.
Floaters aren’t usually a major issue, but if you suddenly see a big increase in floaters or if they’re accompanied by light flashes or a loss of peripheral vision, seek care right away. These could be signs of a retinal tear or detachment.
Amblyopia
Also sometimes called lazy eye, amblyopia, in which one eye has a better ability to focus than the other, can occur in early childhood. Over time, the brain begins to ignore input from the eye that’s less clear, leading to imbalances in visual acuity.
Amblyopia may be caused by a condition called strabismus (colloquially known as crossed eyes) in which the eyes point in different directions.
Refractive errors, such as being nearsighted, farsighted or having an astigmatism (distorted or blurry vision), can also contribute. In addition, some children are born with a cataract, which can also cause amblyopia.
How to Preserve Good Eye Health for a Lifetime
Some eye conditions become more likely with time, which is why it’s so important to schedule routine eye exams.
“Even if your vision seems fine, routine eye checkups can catch problems before they cause irreversible damage,” Ng says.
Taking care of your overall health by eating right, managing your weight, getting routine health exams and staying active can also help support good eye health into your golden years.
“By taking proactive steps, you can safeguard your sight and maintain a lifetime of clear vision,” Ng says.
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A Patient’s Guide to Eye Disease originally appeared on usnews.com
Update 02/26/25: This story was previously published at an earlier date and has been updated with new information.
