Keratoconus

Those at risk of progressive keratoconus are:

• Those who rub their eyes, whether for allergy, dryness, or discomfort
• Those who have eczema, asthma, hayfever and/or allergic eye disease
• Those who have a relative with the disease
• Those under the age of 40

Keratoconus causes progressive blurring of vision in one or both eyes over many years, usually from early teens to mid-thirties. Patients find themselves changing their glasses frequently, as this is initially helpful in keratoconus. Patients often have eye allergy, with itch and eye rubbing, which are thought to aggravate the condition.

Occasionally, very thin keratoconic corneas may develop sudden swelling, called hydrops. This causes a dramatic worsening of the vision in one eye and may take months to recover.

The vision loss from keratoconus may range from mild blurring, making night driving difficult, to severe, affecting employment and a patient’s quality of life.

The diagnosis of keratoconus is often missed for several years before it is definitively diagnosed with the aid of a corneal topographer such as a Pentacam. Increasing myopia and astigmatism, particularly if in one eye more than the other, are often clues that the patient needs to be investigated further by an ophthalmologist.

The management of keratoconus involves three aspects:

1. Optimising the optics of the eye: Depending on the severity of keratoconus, this may be in the form of prescribing glasses or hard contact lenses.
2. Preventing further loss of vision: The management of any eye allergy and the avoidance of eye-rubbing may prevent further loss of vision, but patients still need to be continually monitored for any progressive keratoconus. If found to be at risk of future progression, then a procedure called Corneal Collagen Crosslinking (CXL) may be recommended.
3. Other surgical management: Some patients may require surgical treatment that can include:
   • deep anterior lamellar keratoplasty (DALK) corneal transplantation
   • penetrating keratoplasty (PK) corneal transplantation
   • intrastromal corneal ring segment implantation
   • corneal allogenic intrastromal ring segments (CAIRS)
   • CXL-plus and/or photorefractive keratectomy (PRK) laser

Because early intervention, particularly with CXL in at-risk patients, is the key to preventing lifelong vision loss, patients who are suspected of having keratoconus should have an immediate ophthalmic review with corneal topography.