What is Keratoconus?
Keratoconus is a progressive eye condition where the cornea — the clear, dome-shaped front surface of the eye — gradually thins and bulges outward into a cone shape. This abnormal shape causes light entering the eye to be scattered unevenly, resulting in distorted and blurred vision.
The word comes from Greek: "kerato" (cornea) + "konos" (cone).
It typically begins in the teenage years or early 20s and can progress for 10–20 years before stabilizing. It usually affects both eyes, though often one eye is worse than the other.
Symptoms
Early Stage
Slightly blurry or mildly distorted vision
Increased sensitivity to light and glare
Frequent changes in eyeglass prescription
Difficulty seeing clearly at night
Mild eye irritation or rubbing
Moderate Stage
Noticeable distortion — straight lines appear wavy or bent
Ghosting or multiple images from one eye
Glasses no longer fully correct vision
Halos around lights, especially at night
One eye significantly worse than the other
Advanced Stage
Severely distorted vision that glasses cannot fix
Cornea becomes visibly cone-shaped
Sudden episodes of swelling and sharp pain (called acute hydrops)
Scarring of the cornea leading to permanent vision loss
⚠️ Key sign to watch: If your glasses prescription keeps changing every few months — especially increasing astigmatism — get a corneal topography test done immediately.
Causes & Risk Factors
The exact cause is not fully understood, but contributing factors include:
Genetics — 1 in 10 patients has a family member with keratoconus
Chronic eye rubbing — one of the strongest known triggers; very common in India due to allergies
Allergic eye disease — atopic keratoconjunctivitis and vernal keratoconjunctivitis
Connective tissue disorders — Marfan syndrome, Ehlers-Danlos syndrome
Down syndrome
Prolonged contact lens wear without proper care
UV exposure — relevant in high-sunlight countries like India
Diagnosis
Corneal Topography — Maps the shape and curvature of the cornea. The gold standard test.
Corneal Tomography (Pentacam) — Provides 3D imaging of corneal thickness and elevation. Essential before any surgical planning.
Slit Lamp Examination — Doctor examines the cornea under magnification for thinning or Fleischer ring (iron deposits).
Pachymetry — Measures corneal thickness.
Treatment
Treatment depends entirely on the stage of the condition:
Stage 1 — Mild | Spectacles & Soft Lenses
Standard glasses or soft contact lenses can correct vision in the very early stages. However, as the cornea changes shape, these become less effective over time.
Stage 2 — Moderate | Specialty Contact Lenses
Rigid Gas Permeable (RGP) Lenses — Hard lenses that vault over the irregular cornea and create a smooth optical surface. Widely used in India.
Scleral Lenses — Larger lenses that rest on the white of the eye, completely vaulting the cornea. Excellent comfort and vision correction. Increasingly available in Indian metro cities.
Hybrid Lenses — Hard centre with a soft skirt for comfort. A middle ground between RGP and soft lenses.
Stage 3 — Halt Progression | Corneal Cross-Linking (CXL)
Corneal Collagen Cross-Linking is the only treatment that stops keratoconus from getting worse. It does not reverse existing damage — but it prevents further progression.
The procedure involves:
Riboflavin (Vitamin B2) eye drops applied to the cornea
UV-A light exposure for 30 minutes
This creates new collagen bonds, stiffening and strengthening the cornea
Available widely across India — at Aravind Eye Care, Sankara Nethralaya, LV Prasad, and most major ophthalmology centres. Cost ranges from ₹25,000–₹60,000 per eye.
Stage 4 — Advanced | Surgical Options
Intrastromal Corneal Ring Segments (ICRS / Intacs) — Tiny plastic rings inserted into the cornea to flatten and reshape it. Improves vision and contact lens tolerance. Often combined with cross-linking.
Deep Anterior Lamellar Keratoplasty (DALK) — A partial corneal transplant where only the front layers are replaced, keeping the patient's own inner layer (endothelium). Lower rejection risk than full transplant.
Penetrating Keratoplasty (PKP) — Full corneal transplant. Reserved for end-stage keratoconus with severe scarring where no other option works. Success rates are high but recovery is long (1–2 years).
Quick Summary Table
StageConditionTreatmentEarlyMild blur, changing glassesSpectacles, soft lensesModerateDistortion, poor glasses correctionRGP / Scleral lensesProgressiveCornea still changingCorneal Cross-Linking (CXL)AdvancedSevere distortion, scarringICRS rings + CXL, DALK, PKP
Important for Indian Patients
Eye rubbing is extremely common in India due to dust, pollution, and allergic eye disease. This is one of the biggest preventable triggers — never rub your eyes.
Keratoconus is more prevalent in South Asian populations compared to Western populations.
Early diagnosis with corneal topography is critical — many patients in India are diagnosed late because they assume blurry vision is just a glasses problem.
Cross-linking is now available across tier-1 and many tier-2 cities in India at reasonable costs.