Eye Health Glossary: A Comprehensive A-Z Guide to Understanding Your Vision (Part 1: A-M)

Understanding your vision health is essential for maintaining clear and comfortable eyesight throughout your life’s journey. Whether you’re well-versed in common eye conditions or just beginning to explore the world of eye health, this guide is here to illuminate essential terms and conditions that impact your vision. With Zenni’s commitment to your eye health, we’re dedicated to supporting you in achieving optimal vision care. Let’s delve into the A-Z of eye health to empower you with knowledge that enhances your eye care journey.

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A: Astigmatism

Astigmatism is a common refractive error where the eye’s cornea or lens has an irregular shape, causing blurred or distorted vision at all distances. It often coexists with other refractive errors like nearsightedness or farsightedness.

B: Blepharitis

Blepharitis is inflammation of the eyelids, typically caused by bacterial infection or skin conditions. Symptoms include redness, itching, and irritation of the eyelid margins, sometimes leading to dry eye syndrome.

C: Cataracts

Cataracts involve the clouding of the eye’s natural lens, leading to blurry vision, sensitivity to light, and difficulty seeing at night. This condition usually develops slowly and can be treated with surgery to replace the cloudy lens with an artificial one.

D: Diabetic Retinopathy

Diabetic retinopathy is a complication of diabetes that affects the blood vessels of the retina. High blood sugar levels damage blood vessels, causing them to leak fluid or bleed, leading to vision impairment or blindness if untreated.

E: Eyestrain

Eyestrain occurs from prolonged use of digital devices or reading without breaks. Symptoms include headaches, dry eyes, and blurred vision. Proper lighting, frequent breaks, and using computer glasses can help alleviate eye strain.

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F: Farsightedness (Hyperopia)

Farsightedness is a refractive error where distant objects are seen clearly, but close-up objects appear blurry. This happens because light focuses behind the retina rather than directly on it. Eyeglasses, contact lenses, or refractive surgery can correct hyperopia. Discover how glasses correct vision by clicking here.

G: Glaucoma

Glaucoma refers to a group of eye conditions that damage the optic nerve, often due to increased intraocular pressure. This damage can lead to irreversible vision loss if untreated. Early detection through regular eye exams and treatment with eye drops, laser surgery, or microsurgery can help prevent vision loss.

H: Hordeolum (Stye)

A hordeolum, commonly known as a stye, is a small, painful lump that develops on the eyelid due to an infected oil gland. It typically appears as a red, swollen bump near the edge of the eyelid and can be tender to the touch. Warm compresses and proper eyelid hygiene are often recommended for relief and resolution. Click here to learn more about some common eyelid conditions.

I: Iris

The iris is the colored part of the eye that controls the size of the pupil, regulating the amount of light that enters the eye. It adjusts the pupil’s size in response to light intensity and helps protect the retina from too much light exposure.

J: Jaeger Eye Chart

The Jaeger eye chart is used to test near vision, measuring the ability to read small print at a standard distance. It assesses the clarity of close-up vision and is commonly used in optometry offices to prescribe reading glasses.

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K: Keratitis

Keratitis is inflammation of the cornea, the clear front surface of the eye. It can be caused by infections, injuries, or underlying conditions like dry eye syndrome. Symptoms include eye pain, redness, blurred vision, and sensitivity to light.


LASIK (laser-assisted in situ keratomileusis) is a popular surgical procedure to correct refractive errors like nearsightedness, farsightedness, and astigmatism. It reshapes the cornea with a laser to improve how light is focused onto the retina, reducing or eliminating the need for glasses or contact lenses.

M: Macular Degeneration

Macular degeneration is a progressive eye disease that affects the macula, the central part of the retina responsible for sharp, central vision. It can result in blurred or distorted vision, making activities like reading and driving difficult. Age-related macular degeneration (AMD) is the most common form, often occurring in older adults.

Maintaining clear and comfortable eyesight throughout your life is essential for your overall well-being. Whether you’re well-versed in common eye conditions or just starting to learn about them, this guide empowers you to identify symptoms, explore treatments, and prioritize proactive eye care. At Zenni, we’re dedicated to enhancing your vision and lifestyle, offering support at every stage. Look forward to Part 2, where we’ll further explore the world of eye health, providing you with the tools to maintain optimal vision for years to come.

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Alyssa Buchanan

Dr. Alyssa Buchanan is an optometrist based in Lubbock, Texas. She received her doctorate from Western University of Health Sciences in Pomona, California, and has practiced in various settings including Fort Cavazos where she provided eye care for deploying soldiers. Dr. Buchanan has since received her Master’s degree in Healthcare Administration and continues to strive to provide top-notch eyecare and make a meaningful impact in the eyecare industry.