What Is it, Causes, Treatment, and More

Author: Lily Guo

Editors: Alyssa Haag, Kelsey LaFayette, BAN, RN

Illustrator: Jillian Dunbar

Copyeditor: Joy Mapes

What is anopia?

Anopia, also known as blindness, is the absence of vision due to either a structural defect of the eye(s) or the lack of the eye(s) completely. Anopia can occur in one or both eyes and lead to problems with walking, balance, and navigation. 

Typically, light from the environment is able to pass through the cornea, the clear window located in the front of the eye. Based on the amount of light in the environment, the iris, the colored part of the eye, then controls the size of the pupil, which is the dark, circular opening in the center of the eye. The size of the pupil allows specific amounts of light to pass through the lens, and the lens focuses the light rays onto the retina. The retina typically sits at the back of the eye and conveys the information from the environment to the optic nerve and the brain. A disruption to any part of this pathway can cause anopia

What causes anopia?

Anopia can be caused by damage to the eye as a result of trauma, inflammation, or infection. Mechanical trauma can be the result of situations like getting hit in the eye with an object. Inflammation can damage the optic nerve and is often due to inflammatory or autoimmune diseases. Such diseases include multiple sclerosis, which damages the brain and spinal cord, and systemic lupus erythematosus, a disease in which the body’s own immune system attacks its tissues. Cataracts of the eye, which involve clouding of the lens, can also lead to anopia and are most commonly due to aging. Similarly, age-related macular degeneration, characterized by the breakdown of the central part of the retina, can potentially cause anopia. Moreover, diabetes, a disease characterized by elevated blood sugar levels, can lead to retinal damage and anopia in a condition known as diabetic retinopathy

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How is anopia treated?

If anopia is due to refractive errors, where the lens cannot change shape to focus the light on the retina, such as with cataract formation, then treatment is currently available. Cataracts are commonly treated by an opthamologist with a surgical procedure to remove the defective lens and replace it with an artificial lens. However, with most other underlying causes, treatment is focused on managing the symptoms. 

An individual with anopia may be advised to see an ophthalmologist or optometrist, clinicians who specialize in treating disorders of the eye. A clinician may prescribe optical aids, such as glasses or contact lenses, for individuals who have vision remaining. Optical aids, however, will not prevent the progression of most conditions to full blindness

For long-term management, refractive surgery may be performed. This involves reshaping the cornea with a laser to restore the cornea to typical functioning. Unfortunately, retinal degeneration disorders (e.g., age-related macular degeneration, diabetic retinopathy) currently have no cure, as these diseases break down the retina in an irreversible manner. 

Anopia can have a significant effect on quality of life. Anopia can lead to impairment in reading, driving, and navigation, which may make it more difficult for an individual to complete daily tasks independently. If the effects of anopia cannot be managed with prescription optical aids or other treatment, physical therapy may be advised to help with balance, walking, and, if needed, the use of a cane. An occupational therapist can also work with an individual to develop accessible ways to approach daily tasks. Additionally, a mental health professional can help the individual process the life changes and emotional distress that can come with vision loss

What are the most important facts to know about anopia?

Anopia is the loss of vision due to damage to or absence of the eye(s). More commonly known as blindness, anopia occurs when trauma, age, or an underlying medical condition, such as diabetes or an autoimmune condition, disrupts the natural pathway of light through the cornea, pupil, lens, retina, and optic nerve. Treatment involves consulting an eye specialist clinician to address the underlying cause or for optical aids. Physical therapists, occupational therapists, and mental health professionals may be consulted for additional support as needed. 

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Related links

Anatomy of the eye
Age-related macular degeneration
Anatomy and physiology of the eye
Cortical blindness

Resources for research and reference

Aguirre GK, Datta R, Benson NC, et al. Patterns of individual variation in visual pathway structure and function in the sighted and blind. PLoS One. 2016;11(11):e0164677. doi:10.1371/journal.pone.0164677

American Academy of Family Physicians. Vision loss. In Diseases and conditions. Published March 5, 2021. Accessed May 3, 2021.

Kelts EA. The basic anatomy of the optic nerve and visual system (or, why Thoreau was wrong). NeuroRehabilitation. 2010;27(3):217-222. doi:10.3233/NRE-2010-0600