Identify and Manage the Stages of Keratoconus?

The progression of keratoconus is classified into stages to help determine severity and guide treatment. Doctors commonly use the Amsler-Krumeich system, which divides keratoconus into four stages: mild, moderate, advanced, and severe. Diagnostic tools like corneal topography, pachymetry, and keratometry are essential for accurately assessing each stage.

Stage 1: Early or Mild Keratoconus

In the early stage of keratoconus, changes in the cornea are subtle. The corneal curvature begins to steepen slightly, but there is little to no scarring. Vision may be mildly blurred, especially in low light or at night, and patients might notice minor astigmatism or nearsightedness. At this stage, prescription eyeglasses or soft contact lenses often suffice to correct vision.

Rigid gas permeable (RGP) lenses can provide sharper vision by maintaining a regular optical surface over the cornea. Regular eye examinations, including corneal topography or tomography, are essential to track any changes in the cornea. Many patients at this stage may not realize they have keratoconus, as symptoms are often subtle, including halos around lights or slight ghosting of images. Early detection can significantly reduce the risk of progression to more advanced stages

Stage 2: Moderate Keratoconus

As keratoconus progresses to the moderate stage, corneal steepening becomes more noticeable, and scarring may begin to appear. Patients often experience more pronounced vision distortion, astigmatism, and sensitivity to glare. Standard glasses are usually no longer sufficient to provide clear vision.

Specialized RGP lenses or hybrid lenses, which combine a rigid center with a soft outer skirt for comfort, are commonly used. Corneal collagen cross-linking (CXL) is often recommended at this stage to stabilize the cornea and prevent further bulging. During CXL, riboflavin (vitamin B2) eye drops are applied to the cornea and activated with UV light to strengthen the collagen fibers.

In some cases, Intacs or corneal inserts may be recommended to reshape the cornea and improve visual quality. Regular follow-up appointments every three to six months are necessary to monitor the cornea and ensure lenses remain effective. Patients in this stage may experience frequent changes in their prescription and difficulty performing tasks like night driving due to glare and halos.

Stage 3: Advanced Keratoconus

In advanced keratoconus, the cornea exhibits significant thinning, pronounced bulging, and visible scarring. Vision is severely distorted, and everyday activities such as reading or driving may become challenging. Glasses are often ineffective, and contact lenses are the main form of vision correction.

Custom RGP lenses or scleral lenses, which vault over the irregular cornea, provide improved clarity and comfort. Cross-linking may still be performed if progression is detected. Management of corneal hydrops, a sudden buildup of fluid in the cornea, may also be necessary. Advanced imaging techniques, including corneal tomography, help eye care specialists assess both anterior and posterior corneal surfaces and plan the most effective interventions. Patients often experience eye strain, headaches, and difficulty adapting to vision changes, making timely care crucial for quality of life.

Stage 4: Severe Keratoconus

The severe stage of keratoconus is characterized by extreme corneal thinning, extensive bulging, and scarring. Vision is profoundly impaired, and many patients cannot tolerate standard contact lenses. In these cases, a corneal transplant, either full-thickness (penetrating keratoplasty) or partial-thickness (deep anterior lamellar keratoplasty, or DALK), may be required to restore vision.

Scleral lenses are often used post-transplant or in cases of unusually shaped corneas to provide stability and comfort. Careful monitoring after surgery is essential to ensure proper healing, prevent complications, and maintain lens fit. Patients at this stage may feel anxious or frustrated due to their visual limitations, and expert guidance is essential to improve outcomes and restore confidence in daily activities.

How Keratoconus Progresses

The rate of keratoconus progression varies among individuals. Progression is typically faster in younger patients and can differ between each eye. The most significant changes often occur in the first 15–20 years after onset, with stabilization usually around age 40–45. However, minor progression can continue in some individuals even after this age. Early detection and regular monitoring are crucial to prevent severe vision loss and to intervene at the optimal time with treatments such as cross-linking or specialized contact lenses.

Modern Diagnostic Tools for Staging

Modern diagnostic tools have revolutionized keratoconus management.

• Corneal topography and tomography provide detailed maps of the corneal surface, highlighting irregularities and steepening patterns.
• Pachymetry measures corneal thickness at multiple points, aiding in staging and treatment planning.
• Artificial intelligence (AI) is increasingly being used to analyze corneal images and predict disease progression.

The Belin ABCD Progression Display integrates multiple metrics, including anterior and posterior corneal curvature, corneal thickness, and visual function, providing a comprehensive view of disease progression and helping clinicians make precise treatment decisions.

Frequently Asked Questions