Common Vision Problems and Eye Conditions

How the eye works and where problems arise

Light passes through the cornea and lens, which focus it onto the retina at the back of the eye. The retina's center, the macula, provides sharp detail. The optic nerve carries the signal to the brain. Vision problems arise from:

• focusing errors (cornea and lens shape or eye length)
• clouding of the lens (cataract) or cornea
• damage to the retina or macula (macular degeneration, diabetic retinopathy, detachment)
• optic nerve damage (glaucoma, optic neuritis)
• brain pathways (stroke, tumors)
• eye alignment and development in children (amblyopia, strabismus)

For a symptom-led guide to what different visual symptoms mean and when they are urgent, see vision problems symptoms.

Refractive errors

Myopia is increasingly common in children worldwide, linked to time spent on close work and less time outdoors. Treatment options include glasses, contact lenses and refractive surgery (LASIK, PRK, SMILE or lens implants). Low-dose atropine drops, special glasses and contact lenses can slow myopia progression in children.

Cataract

The lens gradually clouds, usually with age, but also from diabetes, steroids, smoking, UV exposure and eye injury. Symptoms are blur, glare, halos, dull colors and poor night vision. Surgery replacing the cloudy lens with a clear artificial lens is one of the most common and successful operations. See cataract.

Glaucoma

A group of diseases that damage the optic nerve, often with raised eye pressure. The common open-angle type causes slow, painless loss of side vision that is not noticed until late. Acute angle-closure glaucoma causes a sudden painful red eye and is an emergency. Treatment with pressure-lowering drops, laser or surgery prevents further loss but cannot restore lost vision. See glaucoma.

Age-related macular degeneration

Damage to the macula in people over 50 causes blurred and distorted central vision while side vision is preserved. The dry form progresses slowly; the wet form progresses quickly and is treated with injections into the eye. Specific vitamin supplements (the AREDS2 formula) slow progression in intermediate disease. See macular degeneration.

Diabetic retinopathy

High blood sugar damages retinal blood vessels, causing leakage, swelling of the macula and growth of fragile new vessels that bleed. It is often symptomless early. Yearly dilated eye exams, good blood sugar and blood pressure control, laser treatment and injections prevent most severe vision loss. See diabetic retinopathy.

Childhood vision problems

• Amblyopia (lazy eye): one eye does not develop normal vision because the brain favors the other eye, due to misalignment, a big prescription difference or a blocked view (such as ptosis or cataract). Treated with glasses, patching or atropine drops, best before age 7 to 8.
• Strabismus: misaligned eyes (turned in, out, up or down). Treated with glasses, patching and sometimes surgery.
• Refractive errors: often found at school screening.

Other common eye conditions

• Dry eye: gritty, burning, fluctuating vision; very common with age, screens and some medicines.
• Eye strain: tired, sore eyes and headaches after prolonged near work or screens.
• Floaters: common with age; new showers of floaters need checking for a retinal tear.
• Retinal detachment, vein and artery occlusions: less common but urgent.
• Low vision: permanent vision loss that glasses cannot correct, managed with magnifiers, lighting, and rehabilitation.

How vision problems are diagnosed

A comprehensive eye exam by an optometrist or ophthalmologist includes:

1. Visual acuity with a letter chart for each eye.
2. Refraction to find the best glasses prescription.
3. Slit-lamp examination of the lids, cornea, lens and front chamber.
4. Eye pressure measurement (tonometry) for glaucoma.
5. Dilated retinal examination of the retina, macula and optic nerve.
6. Visual field testing for side vision.
7. OCT imaging of the retina and optic nerve.

How often to have an eye exam

• Children: vision screening at well-child visits, with a full exam if a problem is suspected.
• Adults without symptoms or risk factors: a baseline comprehensive exam at 40.
• Adults 65 and older: every 1 to 2 years.
• People with diabetes: a dilated exam at least yearly.
• People with a family history of glaucoma or other risks: as advised, often more frequently.

Treatment overview

Prevention

• Have regular eye exams appropriate to your age and risk.
• Do not smoke.
• Wear UV-blocking sunglasses and protective eyewear.
• Control diabetes, blood pressure and cholesterol.
• Encourage children to spend time outdoors, which reduces the risk of myopia.
• Take regular breaks from screens.

Frequently asked questions

What are the most common vision problems?

The most common are refractive errors: nearsightedness, farsightedness and astigmatism, plus presbyopia after age 40. All are corrected with glasses, contact lenses or surgery. Cataracts are also very common in older adults and are treated with surgery.

What are the leading causes of vision loss?

In adults in the US and Europe, the leading causes of serious vision loss are age-related macular degeneration, cataract, glaucoma and diabetic retinopathy. Worldwide, uncorrected refractive errors and cataracts are the biggest causes of vision impairment, and both are treatable.

Can vision problems be prevented?

Many can be prevented or slowed. Regular eye exams catch glaucoma and diabetic retinopathy before vision is lost. Not smoking, wearing sunglasses, controlling diabetes and blood pressure, and outdoor time for children all help. Early treatment of amblyopia prevents permanent vision loss.

How do I know if I need glasses?

Signs include blurry distance or near vision, squinting, eye strain, headaches after reading or screens, and holding things at arm's length to read. An eye exam with refraction will show whether glasses would help.

Can lost vision be restored?

It depends on the cause. Vision lost to refractive errors and cataracts can be fully restored. Treatment can improve vision in wet macular degeneration and diabetic macular swelling. Vision lost to glaucoma or optic nerve damage usually cannot be restored, which is why early detection matters.