Keratoconus

Keratoconus Care in Melbourne's Northern Suburbs

Keratoconus is a progressive condition affecting the cornea — the clear front surface of the eye. Northern Eye Consultants provides specialist assessment and management of keratoconus from our consulting rooms at Northpark Hospital, Bundoora, serving patients from Epping, Mill Park, Greensborough, Diamond Creek, Eltham, Thomastown, Reservoir, and across Melbourne's northern suburbs.

Dr Ross MacIntyre is our corneal subspecialist. He completed his fellowship training in cornea, complex cataract, and refractive surgery at the Wilmer Eye Institute at Johns Hopkins University in Baltimore — one of the world's leading eye hospitals — and pursued further corneal training at the Royal Victorian Eye and Ear Hospital. Detailed procedure information is available at corneaeyedoctor.com/keratoconus.

What is Keratoconus?

Keratoconus is a condition in which the cornea progressively thins and steepens, causing it to bulge forward into an irregular, cone-like shape. This distorts the cornea's optical properties, producing irregular astigmatism and progressive blurring of vision that cannot be fully corrected with standard spectacles. The word keratoconus is derived from the Greek and Latin words for "cornea" and "cone".

The condition most commonly presents in adolescence or early adulthood — typically between the ages of 10 and 25 — and may progress through the twenties and thirties before stabilising. Keratoconus affects approximately 1 in 2,000 people in the general population, though milder forms detected on topography are considerably more common.

The cause of keratoconus involves a combination of genetic predisposition and environmental factors. A positive family history is found in 10–15% of cases. Eye rubbing — a common habit in people with allergic eye disease — is an established risk factor and should be actively avoided by anyone with keratoconus or a family history of the condition.

Symptoms

Early keratoconus may produce symptoms that initially resemble ordinary short-sightedness or astigmatism. As the condition progresses, symptoms become more characteristic:

• Blurred or distorted vision — Particularly at distance, and often unequal between the two eyes.
• Monocular diplopia — Ghost images or multiple images seen with one eye, caused by irregular corneal shape.
• Glare and halos — Especially around lights at night, due to light scatter from the irregular corneal surface.
• Photophobia — Increased sensitivity to light, particularly in moderate to advanced disease.
• Frequent prescription changes — Needing new glasses every few months, with spectacles never quite correcting vision to a satisfactory level.
• Contact lens intolerance — Soft lenses may not sit properly on the irregular cornea; RGP or scleral lenses are often required.

Diagnosis

A diagnosis of keratoconus is based on a combination of clinical examination and advanced corneal imaging.

On slit lamp examination, advanced keratoconus produces characteristic signs including Vogt's striae (fine vertical stress lines in the deep stroma), a Fleischer ring (an iron ring at the base of the cone, visible with cobalt blue light), and Munson's sign (a V-shaped indentation of the lower lid when the patient looks downward).

Corneal topography maps the curvature of the anterior corneal surface and is the standard screening tool for keratoconus. A characteristic inferior or inferior-temporal steepening pattern is typical.

Pentacam / Scheimpflug imaging provides a three-dimensional map of the entire cornea — front and back surfaces — as well as precise measurement of corneal thickness at every point. This allows detection of early keratoconus (including subclinical or forme fruste keratoconus), accurate monitoring of progression, and assessment of cross-linking candidacy.

Pachymetry measures corneal thickness — a critical parameter in determining whether cross-linking is safe and in planning any surgical intervention.

Non-Surgical Management

The aim of non-surgical management is to provide the best possible visual acuity by neutralising the irregular astigmatism of the keratoconic cornea. Options depend on the severity of disease.

Spectacles correct mild regular astigmatism associated with early keratoconus but are unable to correct the irregular astigmatism of moderate or advanced disease.

Soft contact lenses may be adequate in very mild cases but are generally unsatisfactory as the condition advances because they conform to the irregular corneal surface rather than masking it.

Rigid gas permeable (RGP) contact lenses vault over the corneal surface, creating a smooth optical interface filled with tears. They provide excellent vision for many patients with moderate keratoconus and remain a mainstay of management.

Scleral contact lenses are large-diameter lenses that rest on the white of the eye (sclera) and completely vault the cornea, making them highly effective for advanced or irregular keratoconus. Northern Eye Consultants does not fit scleral lenses directly but can refer to specialist contact lens practitioners when scleral lenses are indicated.

Corneal Cross-Linking (CXL)

Corneal cross-linking (CXL) is the only proven treatment to halt keratoconus progression. It does not reverse existing corneal irregularity, but in the majority of patients it stops further deterioration — protecting the patient's own cornea and preserving the option of contact lens correction rather than progressing to transplantation.

The standard technique is the epithelium-off (Dresden) protocol. The outer layer of corneal cells (epithelium) is removed, and riboflavin (vitamin B2) drops are instilled for 30 minutes. The cornea is then exposed to a calibrated dose of ultraviolet A light for a further 30 minutes. The riboflavin absorbs the UV energy and catalyses the formation of new covalent bonds between corneal collagen fibrils — increasing stromal stiffness and resistance to progressive ectasia.

Candidacy criteria for cross-linking include documented progression of keratoconus on serial topography or pachymetry, a minimum corneal thickness of approximately 400 microns at the thinnest point (to protect the endothelium from UV exposure), and the absence of significant corneal scarring. Age is not a barrier — cross-linking in adolescents and young adults is well-evidenced and important, as younger patients typically have more aggressive progression.

After cross-linking, vision is typically blurred for several weeks as the epithelium heals. Contact lens use usually resumes within 4–6 weeks. Full assessment of the treatment effect is performed at 3–12 months. Most patients achieve stabilisation; a proportion may see mild improvement in corneal curvature over the following year.

Intacs (Intrastromal Corneal Ring Segments)

Intacs are small, crescent-shaped polymethylmethacrylate implants inserted into tunnels within the corneal stroma. They flatten and regularise the central cornea, potentially improving both uncorrected and contact lens-corrected vision. Intacs are occasionally used in patients who are not contact lens tolerant and are not yet ready for transplantation. They are not widely used in Australia and are generally considered when other options have been exhausted.

CAIRS (Corneal Allogenic Intrastromal Ring Segments)

CAIRS is an emerging technique in which segments of donor corneal stroma are fashioned into intrastromal ring shapes and implanted into the keratoconic cornea. Unlike synthetic Intacs, CAIRS use biocompatible donor tissue. Early results are encouraging, with potential advantages in terms of integration and adjustability. However, CAIRS remains an experimental procedure that is not yet widely available in Australia. Dr MacIntyre can discuss emerging options with patients for whom standard treatments have been inadequate.

Corneal Transplantation for Keratoconus

A small proportion of patients with keratoconus — particularly those with advanced disease, significant scarring, or intolerance to contact lenses — require corneal transplantation to restore adequate functional vision.

Deep Anterior Lamellar Keratoplasty (DALK) is the preferred surgical technique for keratoconus. DALK replaces the anterior (front) layers of the cornea — including the stroma — with donor tissue, while preserving the patient's own inner cell layer (endothelium). Because the endothelium is preserved, the risk of rejection is significantly lower than with full-thickness transplantation, and the patient retains the most important determinant of long-term corneal health. Vision after DALK is comparable to that achieved with full-thickness transplantation. Recovery involves suture management over 12–18 months. Full details of the DALK procedure are available at drmacintyre.com/cornea-surgery.

Penetrating Keratoplasty (PKP) — full-thickness corneal transplantation — is required in cases where DALK is not technically feasible, such as when there is a corneal perforation or when the endothelium has been compromised by disease or previous surgery.

For a comprehensive overview of corneal conditions we treat, visit our Corneal Disease page.