Cataracts, glaucoma, and refractive errors are just a few examples of conditions that cause visual impairment, a decline in your ability to see that’s significant enough to affect daily life.
“Visual impairment” is a broad term describing vision loss from conditions that alter the systems, structures, or functions of the eye. It includes low vision, where some sight remains, as well as conditions of blindness.
Visual impairment can involve changes to the clarity or acuity of your vision and losses to your field of view, eye coordination, depth perception, light sensitivity, and color contrast.
According to the
Almost everyone’s vision changes naturally with age. The older you are, the more likely you’ll develop at least one form of visual impairment.
Globally, the
- refractive errors
- cataract
- diabetic retinopathy
- glaucoma
- age-related macular degeneration
A global
Cataracts
A cataract occurs when the natural lens of your eye becomes cloudy, limiting how well light passes into the retina. Most cataracts develop slowly, as degenerative processes cause proteins to clump within the eye’s lens.
You can develop a cataract in one eye or both eyes. If you have cataracts in both eyes, they may progress at different rates and affect your vision with different severity.
Cataracts are known for causing blurred or cloudy vision, faded color perception, low night vision, and seeing “halos” around lights.
Glaucoma
Glaucoma occurs when damage to the optic nerve affects how your eyes transmit visual signals to your brain. Most cases of glaucoma are caused by increased intraocular pressure (IOP), a measurement of the force exerted within your eye by clear fluid called the aqueous humor.
- open-angle glaucoma
- angle-closure glaucoma
- normal tension glaucoma
- steroid-induced glaucoma
- pseudoexfoliation syndrome (PEX)
Glaucoma affects your peripheral vision or your side vision. It’s often subtle, with no obvious signs or symptoms until its advanced stages. Angle-closure glaucoma, a form of glaucoma that requires urgent medical attention, may cause sudden pain, nausea, blurred vision, or a headache.
Refractive errors
When the shape of your eye alters how light is focused on your retina, it causes a refractive error. If the light isn’t focused on the retina accurately, it distorts or blurs vision at different distances or makes it difficult to focus your eyes.
Types of refractive errors include:
There are many reasons why you might develop refractive errors, including changes to eye lens flexibility, varied eyeball length, and irregularity in your cornea, the clear layer on the front of your eye.
Age-related macular degeneration (ARMD)
Age-related macular degeneration (ARMD) is a progressive condition that affects the macula of your eye, the part of your retina responsible for detailed vision.
ARMD is divided into
In dry ARMD, yellowish deposits called drusen form between your retina and the layers of the eye that supply it with blood. Comprised of fats, proteins, and other cellular waste products, drusen contribute to damage in the retina and photoreceptor cells, which affects central vision.
In wet ARMD, also known as neovascular ARMD, abnormal blood vessels form beneath your macula. They promote fluid leakage that can lead to inflammation and permanent scarring.
ARMD doesn’t always feature symptoms in its early stages. As it progresses, you may notice blurred vision, difficulty seeing in low light, trouble seeing details, or seeing straight lines as wavy.
Diabetic retinopathy
Diabetic retinopathy is a complication of diabetes. It develops when prolonged, elevated blood sugar levels (hyperglycemia) put stress on your retinal cells, trigger inflammation, and promote the development of new, leaky blood vessels on the surface of the retina or in the vitreous, the gel-like substance filling the eye.
Blood from abnormal, leaky vessels can cloud the vitreous, leading to sudden vision impairment or loss. New vessels on the surface of the eye can pull your retina away from its natural position, resulting in retinal detachment.
Diabetic retinopathy doesn’t always present with symptoms in its early stages. As it progresses, you may notice sudden vision changes, floaters or spots in your eyes, blurry vision, or difficulty seeing in low light.
Visual impairment describes a spectrum of vision loss across a variety of eye conditions. Below are answers to some commonly asked questions:
What is the difference between vision impairment and blindness?
“Vision impairment” is an umbrella term that describes different severities of vision loss affecting daily life. Total blindness, the absence of any light perception, is considered a severe form of visual impairment.
What level of vision loss is considered a disability?
In the United States, the Social Security Administration considers you eligible for disability benefits if you’re “legally blind.” There are two qualifications for legal blindness:
- having vision in your best eye that can’t be corrected to better than 20/200
- having a visual field of 20 degrees or less in your best eye for an expected or experienced period of 12 months
Even if you don’t meet these criteria, you may be eligible for disability benefits if vision challenges prevent you from maintaining employment.
What doctor do you consult for visual impairments?
Visual impairment is primarily treated by ophthalmologists and optometrists, though your eye care team may involve other specialists depending on the cause of vision impairment.
If you need help covering the cost of eye care, consider contacting:
“Visual impairment” is a broad term that describes vision loss across a spectrum of severity and conditions. It includes legal or total blindness, which are complete or near-complete states of vision loss.
Cataracts, glaucoma, and refractive errors are the most common forms of visual impairment globally.