Keratoconus: progression, acute hydrops, and care concepts

What it is

Keratoconus is a corneal ectatic disease: the central or paracentral cornea gradually thins and bulges forward in a cone shape, causing irregular astigmatism and deepening myopia. Vision blurs and spectacles often cannot fully correct it.

Public-education points:

• Often found from adolescence to young adulthood; both eyes may be involved, but asymmetry is common.
• Causes are multifactorial: genetic tendency, environment and behaviour (especially forceful eye rubbing and severe allergic eye disease).
• Progression means ongoing steepening, thinning, or clear worsening of vision / refraction — whether it is “still progressing” needs serial topography / tomography comparison, not feeling alone.
• Acute corneal hydrops: sudden break in Descemet’s membrane (and related structure), aqueous entering the stroma, rapid corneal clouding, sudden vision drop, irritation and pain — a known but relatively uncommon acute complication.
• Two care layers (concepts): (1) slow or stop biomechanical worsening — corneal collagen cross-linking (CXL) class; (2) improve optical quality — spectacles, rigid gas-permeable lenses, scleral lenses and similar classes; transplantation is considered later.

This page discusses classes and principles only — no brand comparison and no success rates. See related pages for refractive-surgery screening, allergy and rubbing, and contact-lens infection red flags.

Common symptoms

• Gradual blur; astigmatism / myopia increasing clearly over a short period
• Many pairs of glasses still unsatisfactory; ghosting, glare, poor night vision; one eye clearly worse
• Young people who itch and rub often from allergy need particular attention
• In acute hydrops: sudden worse blur in one eye, white cloudy cornea, light sensitivity, tearing, discomfort
• Early disease can resemble “ordinary myopia and astigmatism”, so topography / tomography matters in screening (including before refractive surgery)

Go to A&E now (if you cannot get there: call 999)

• Suspected acute hydrops: sudden vision drop, clearly cloudy/white cornea, severe pain or marked light sensitivity
• Contact-lens-related severe red painful eye with heavy discharge — rule out infectious keratitis; do not delay if pain continues after lens removal

Same-day / prompt ophthalmology when possible

• Large refraction change over a short time, or spectacles cannot bring one eye to a reasonable acuity — see an ophthalmologist as soon as possible
• Known keratoconus with new pain or sudden worse blur
• Newly diagnosed children / teens who need assessment of whether progression continues

Routine clinic follow-up

• After diagnosis: repeat topography / tomography, refraction and contact-lens review on the schedule your doctor sets
• Discussion of whether CXL assessment criteria are met (usually emphasises documented progression)
• Allergy control and stop-rubbing education, plus prescription medicines when needed

Tests, optics and CXL (classes)

• Tests: vision, refraction, slit lamp; corneal topography / tomography; thickness. Individual — not a guaranteed checklist
• Optics: spectacles / soft lenses; RGP improves optics and does not by itself stop progression; scleral / mini-scleral; hybrid / piggyback classes — no brand names
• CXL: riboflavin plus UVA aiming to strengthen biomechanics and slow or halt progression; epi-off has more public evidence; important to consider when progression is documented
• Oral riboflavin does not replace a clinical CXL procedure; CXL does not guarantee return to “normal” vision
• Late or severe scarring / extreme thinning: a specialist may discuss corneal transplant classes — individual judgement, no success-rate comparison

Common myths