How we see helps us make sense of the world. So when something seems off with our eyes, it’s no wonder we get worried at the first signs of trouble. Experiencing blurry vision, redness, and other eye symptoms—even mild ones—can really disrupt our lives. What might be going on? 

Here, we’ve compiled a list of the most common eye diseases and disorders, including some helpful info about each, so you can rest a little easier. Read on to learn about everything from refractive errors to cataracts. (But please don’t use this list of eye diseases and disorders to diagnose yourself; see an eye doctor for that!)

Also, please note that this page is solely focused on common eye disorders and diseases. If you don’t find what you’re looking for here, check out this other helpful guide:

Refractive Errors

Diagram of how light focuses in a normal eye, a nearsighted eye, and a farsighted eye

Refraction 101: How light focuses (or doesn’t) on the retina

If you need glasses or contact lenses to see clearly, then you most likely have a refractive error (aka refraction disorder). A refractive error occurs when the shape or structure of your eye prevents light from focusing on your retina with precision. Without that pinpointed focus on your retina, you can’t see as sharply, and objects at certain distances can appear blurred.

Your eye doctor records the type and severity of any refractive errors you have on your eye prescription. Let’s take a look at the four most common types of refraction disorders. 

Nearsightedness (Myopia) 

When you’re nearsighted, you have trouble seeing objects that are far away, like upcoming road signs. This is because the light passing through your eye focuses on a point in front of the retina, rather than on its surface. This eye condition is also called myopia, and it’s becoming increasingly common throughout the globe—in fact, it’s estimated that about half of the entire world will be nearsighted by the year 2050. 

Farsightedness (Hyperopia)

When you’re farsighted, you have trouble seeing objects that are close to you, like your computer screen or a book. Just as nearsighted eyes focus light too far in front of the retina, farsighted eyes focus light on a spot behind it.


Astigmatism is a kind of refraction disorder that can make objects at any distance appear blurry. It results when the curvature of the cornea or the lens of your eye is uneven instead of rounded. Due to this irregular curvature, light that passes through your eye bends abnormally and can’t focus properly on the retina. Fortunately, there are glasses for astigmatism and contacts for astigmatism, too! (Subtle, aren’t we?)


Presbyopia has many of the same symptoms as farsightedness, but the two are not the same. People with presbyopia have lost a degree of flexibility in the lens of their eye. 

Typically, as light passes through your eye, your lens adjusts its shape to focus the light on the retina. But as you get older, your lens tires out a bit. It isn’t as elastic as it once was, and may even be thicker, resulting in a harder time discerning text and objects that are close to your face. 

People with presbyopia can benefit from bifocal or multifocal contacts and glasses, which sharpen their vision at multiple distances. They may also wear reading glasses when they want to pick up a book.

Glasses sitting on a stack of books

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Eye Movement Disorders

Some eye disorders can impact the way that eyes move in their sockets, resulting in (often disrespectful, frankly!) nicknames that reference the eye’s behavior. 

Sometimes, eye movement disorders are referred to as eye muscle disorders—but that’s not always accurate. Although eye movement disorders may sometimes be caused by a problem with the muscles around the eye, other times, these disorders are neurological.

Amblyopia, or “Lazy Eye”

Amblyopia is an inability to see clearly through one eye. This eye movement disorder most often arises during childhood, when the nerve pathway between the brain and affected eye develops abnormally. The eye doesn’t “learn” to see correctly, and the brain eventually starts to favor the other, stronger eye. 

Amblyopia is sometimes referred to as “lazy eye” because the weaker eye can drift in an independent direction. But it’s not very nice to call anything “lazy,” including your eye. We prefer the scientific term.

Strabismus, or “Crossed Eyes”

Strabismus, often called “crossed eyes,” is a condition that causes both eyes to look in different directions. This may be due to a problem with the muscles surrounding the eyes or the brain’s ability to guide those muscles. 


Nystagmus refers to an uncontrollable and rapid movement of the eyes, often with a side-to-side pattern. It’s thought that nystagmus stems from neurological factors, but its exact cause can be hard to discern. 


Glaucoma refers to a group of eye diseases that cause damage to the optic nerve, which can result in vision loss and blindness. Although glaucoma’s exact cause is unknown, it seems to be closely associated with high intraocular pressure—which is why it’s so important to get your IOP tested at regular eye exams.


A cataract is a portion of the lens of your eye that has become cloudy. The hazy appearance comes from proteins that have broken down inside the lens, which can happen naturally with age. Cataracts can impair your vision moderately to severely.

Retinal Eye Disorders

Many serious eye disorders involve the retina. This light-sensitive layer at the back of your eyeball is responsible for sending images to your brain, so it’s crucial to monitor its health! 

As you get older, your macula—the part of your retina that corresponds to seeing straight ahead—may thin or become damaged. When that happens, your central vision worsens, making it tougher to perform certain tasks such as driving and reading. 

Age-related macular degeneration is increasingly common in seniors, and is one of the leading causes of blindness in the elderly population. 

Diabetic Retinopathy 

Diabetic retinopathy is a concern for people with diabetes, and results when high blood sugar damages the blood vessels in your retina. This eye disorder causes the vessels to swell, leak, or become blocked; it can also prompt the formation of new, less-functional vessels. 

If diabetic retinopathy goes unaddressed, it can lead to blindness. But studies have shown that keeping your blood sugar and blood pressure within recommended ranges can lower the risk of its progression. 

Retinal Detachment

In certain circumstances, the retina (or part of it) can become detached from the back of the eye. This usually occurs due to aging or injury, and is considered a medical emergency—surgery is needed to treat a detached retina. 

So, if you notice flashing lights intruding on your vision, a sudden, marked increase in those pesky eye floaters, or what seems like a dark shadow or “curtain” impinging on your sight, we recommend you get to a doctor post-haste.

Two smiling optometrists in white coats

Time for a checkup?

Whether you’re noticing new eye symptoms or just realizing it’s been a while since your last appointment, our expert optometrists are here to help.

Corneal Eye Disorders

The cornea is the clear, outer covering at the very front of your eye that sort of looks (and functions) like a protective dome. It’s an open eye’s first line of defense and also helps to focus light. One of the most common corneal eye disorders is keratoconus.


Keratoconus occurs when the cornea thins out and protrudes into a more cone-like shape. This affects how light enters the eye and causes impaired vision. Mild cases can be corrected by glasses or contacts, whereas highly progressed cases may require surgery. 

Vision Disorders

Eye disorders—as well as the natural process of aging—can give rise to a host of vision problems. These aren’t exactly clinical diagnoses, but are often symptoms of an underlying eye condition. You already know what we’re going to recommend: If you’re experiencing any of these vision issues, see your eye doctor. 

Low Vision 

If you have low vision, then you’re having difficulty seeing clearly to the point where it affects your everyday life. Low vision can’t be fixed with glasses or contacts, and is commonly a symptom of some of the eye disorders we’ve talked about already, including cataracts and age-related macular degeneration. 

Night Blindness

Night blindness, or nyctalopia, is vision disorder that makes it much harder to see in the dark. If you have night blindness, it doesn’t mean you’re completely blind at night, but navigating around a dark room or driving at night can be tough. 

Vision Changes

Some vision changes come naturally with age, and they usually have a slow, progressive onset. Presbyopia, for example, is extremely common in people 40 and older. But sudden vision changes—blurred vision, flashing lights, dark spots, etc.—can be signs of a serious problem, and should always be investigated by a professional ASAP. 

Color Blindness

Individuals with color blindness perceive colors differently from the way most of us do. The degree of color blindness can range from mild to severe—those with very mild color blindness might not even know that they have it. It’s usually a genetic condition, meaning you’re born with it. Because inherited color blindness is carried on the X chromosome, it affects more men than women.

Eye(s) Bothering You? See Your Eye Doctor!

Although it’s long, this list of eye disorders is by no means exhaustive. The best advice we can always offer when your eyes are acting up is to see an eye doctor

Which type of eye doctor? You may ask. Probably an optometrist, but you can read up on the differences between an optometrist and an ophthalmologist to decide which is best suited to your current needs.

In fact, you should see an optometrist regularly anyway, eye issues or no eye issues! It’s one of the best ways to keep your peepers healthy and spot symptoms before your vision becomes at risk. If you take care of your corneas (and everything under ‘em), you’ll up your chances of seeing clearly for years to come. 

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