Condition library
Cornea, conjunctiva and front-of-eye conditions
Conditions of the clear front window of the eye, the white of the eye, the lens and common focusing problems.
Medical reviewer Mr Mohamed Mohyudin, Consultant Ophthalmic SurgeonSite-wide clinical review
About this review
Mr Mohyudin completed a clinical review of the site’s medical content on the date shown. This page has been edited since then; a separate sign-off for this exact version has not yet been recorded, so we do not claim one.
Cornea and front of eye: compared at a glance
Summaries only — follow each link for symptoms, causes, treatment and when to get urgent help.
| Condition | Part of the eye | In brief |
|---|---|---|
| Dry eye | Tear film, tear gland and eyelid | Tears too few or evaporating too fast; overlaps with blepharitis and MGD — lubricants, lid care and prescriptions help most people. |
| Keratoconus | Cornea | The cornea thins and bulges into a cone shape, distorting vision; often starts in the teens or twenties. |
| Corneal abrasion (scratched eye) | Cornea | A scratch on the clear front of the eye; painful but usually heals quickly. Chemical splashes need emergency care. |
| Corneal ulcer | Cornea | An open sore on the cornea, often from infection; a sight-threatening emergency needing urgent care. |
| Fungal eye infection | Cornea | A rare but serious corneal infection, often linked to contact lens wear or eye injury; needs urgent specialist care. |
| Herpes eye infection | Cornea | A cold-sore virus infection of the cornea causing a painful red eye; needs prompt antiviral treatment. |
| Photokeratitis (arc eye) | Cornea | Sunburn of the cornea from UV light, welding arcs or snow glare; painful but usually heals in days. |
| Chemical eye injury | Cornea and conjunctiva | Splash of chemicals into the eye is an emergency; immediate flushing can save sight. |
| Fuchs dystrophy | Cornea | Gradual corneal swelling causing morning blur and glare, usually in older adults; treatable with drops or surgery. |
| Contact lens discomfort | Cornea and tear film | Sore, dry or red eyes with lenses often signals fit, hygiene or surface disease problems — stop lenses and seek advice if pain or vision drops. |
| Pterygium | Conjunctiva and cornea | A fleshy growth on the surface of the eye linked to sun exposure; usually harmless but can affect vision if large. |
| Pinguecula | Conjunctiva | A harmless yellowish bump on the white of the eye, linked to sun and dust exposure. |
| Conjunctivitis | Conjunctiva | Red, irritated eyes from infection or allergy; the cause guides treatment — viral, bacterial and allergic types need different approaches. |
| Viral conjunctivitis | Conjunctiva | Very contagious watery pink eye, often after a cold; antibiotics do not help — hygiene and time are the main treatment. |
| Bacterial conjunctivitis | Conjunctiva | Sticky yellow-green discharge and glued lids, often needing antibiotic drops after assessment; more urgent in babies and contact-lens wearers. |
| Eye allergies | Conjunctiva | Itchy, red, watery eyes from pollen, dust or pets; seasonal peaks in spring and summer respond well to trigger avoidance and allergy drops. |
| Episcleritis | Sclera | A mild, usually painless red eye from surface inflammation; different from the more painful scleritis. |
| Subconjunctival haemorrhage | Conjunctiva | A bright red patch on the white of the eye from a tiny burst vessel; alarming but usually harmless. |
| Cataracts | Lens | Age-related clouding of the lens that blurs and glares; surgery is the only cure when daily life is affected — sudden vision loss is not typical cataract. |
| Ocular rosacea | Eyelid and conjunctiva | Eye irritation linked to the skin condition rosacea; manageable with eyelid care and treatment. |
| Trachoma | Eyelid, conjunctiva and cornea | A leading infectious cause of blindness worldwide, spread by contact and flies; preventable with hygiene and WHO programmes. |
| Foreign body in the eye | Cornea and conjunctiva | Something in the eye causes pain and watering; do not rub, and seek help for metal or plant material. |
| Hyphema | Front chamber | Blood in the front of the eye after injury; needs urgent assessment to protect vision and eye pressure. |
| Vitamin A deficiency and the eye | Conjunctiva, cornea and retina | Lack of vitamin A dries the eye surface and is a leading preventable cause of childhood blindness worldwide. |
| Short-sightedness | Cornea and lens | A very common focusing problem where distant objects look blurred; corrected with glasses, lenses or surgery. |
| Long-sightedness | Cornea and lens | A common focusing problem where near objects look blurred; corrected with glasses, lenses or surgery. |
| Astigmatism | Cornea | A common focusing problem from an unevenly curved eye, causing blur at all distances; easily corrected. |
| Presbyopia | Focusing muscle and lens | The normal age-related loss of near focus from around your mid-40s; corrected with reading glasses or lenses. |
| Digital eye strain | Tear film and focusing muscle and lens | Tired, dry, achy eyes from long screen use; eased by breaks, blinking and screen setup. |
Frequently asked questions
What causes a red eye without much pain?
Conjunctivitis, dry eye, blepharitis and a burst surface vessel are common. A painful red eye is more concerning and should be assessed promptly.
Are contact lenses linked to cornea problems?
Yes. Sleeping in lenses, poor hygiene or swimming in lenses raises the risk of serious corneal infection. Remove lenses and seek same-day advice if the eye becomes painful or red.
When do cataracts need surgery?
When blurred vision interferes with driving, reading or daily life and glasses no longer help. Surgery is usually considered based on symptoms, not the cataract size alone.