What is Keratoconus?

Keratoconus is an eye disease that affects the structure of the cornea, resulting in the loss of vision. The cornea is the clear, dome-shaped, outer surface of the eye. When there is a thinning of the cornea, irregularities on the cornea’s surface or a defective collagen structure in the cornea, the cornea bulges into an irregular cone shape.

Cases of keratoconus usually occur during puberty and the later teenage years. In most instances, both eyes are affected at the same time but the progression of the eye disease may be asymmetrical, with one eye having greater loss compared to the other. This degenerative process may continue for up to 10 or 20 years before naturally stabilising.

There is no known cause for keratoconus but genetics and lifestyle factors such as constantly rubbing of the eyes and living in hot environments are linked with exacerbating the condition. Other factors that may increase your chances of developing keratoconus are health conditions such as Down syndrome, retinitis pigmentosa, hay fever, asthma and Ehlers-Danlos syndrome.

What is Keratoconus?

Image sourced from the Association of Malaysian Optometrists

What happens when you have Keratoconus?

The change in shape of the cornea is due to the tiny protein fibres in your eye (collagen) weakening and unable to hold the shape of the cornea. This happens when you do not have sufficient protective antioxidants in your cornea and the cells produce harmful byproducts.

As the disease progresses, patients normally experience:

Blurred or distorted vision
Double vision
A need to frequently change eyeglass prescriptions
An increased sensitivity to bright light and glare
Bright light appear to have halos or present streaks
Sudden worsening or clouding of vision

In some cases, the cornea can swell and cause a sudden drop in vision and scarring on the cornea. The inner lining of the cornea breaks down and fluid (hydrops) enters the cornea. While the swelling can subside, the scars that are formed can affect vision.

What are the treatments for Keratoconus?

Image sourced from the Association of Malaysian Optometrists

Contact lenses – In the early stages of keratoconus, soft contact lenses may be prescribed to help with vision problems. More rigid, gas-permeable contact lenses may also be prescribed. These only slow the progression of the disease, treat irregular astigmatism and allow patients to go about their daily activities. Contact lenses do not fix the eye condition.

Corneal Cross-Linking (CXL) – This is a minimally invasive outpatient procedure that is aimed at strengthening and stabilising the cornea by creating new links between collagen fibres within the cornea.

The first step of the procedure is applying specially formulated riboflavin (vitamin B) eye drops. Next, the eye is exposed to ultraviolet light that is controlled by the ophthalmologist. In more advanced cases of keratoconus that require the reshaping and stabilisation of the cornea, CXL may be combined with other procedures such as the implantation of tiny arc-shaped corneal inserts (INTACS).

Corneal cross-linking is also performed in other conditions that weaken the structure of the cornea.

Intracorneal Rings (INTACS) – INTACS corneal inserts or implants are primarily performed in cases of keratoconus. Two tiny, clear crescent-shaped plastic polymer pieces are inserted into the cornea to reshape the eye surface.

Corneal Transplants – are when the damaged cornea is removed and replaced with healthy cornea tissue from a donor.

Depending on the level of cornea damage, the Eyecentric ophthalmologist may suggest:

Full thickness corneal transplant (also known as penetrating keratosplasty or PK) – replacement of front and inner corneal layers
Partial thickness corneal transplant (also known as deep anterior lamellar keratoplasty or DALK) – replacement of only the front and middle layers of the cornea
Endothelial keratoplasty – replacement of only the innermost layer of the cornea (endothelium).

When to see an eye specialist?

It is important to make an appointment with an ophthalmologist or optometrist as soon as you notice a rapid change in your vision. Eyecentric specialists at Bukit Tinggi Medical Centre are fully trained to diagnose a wide range of eye conditions and can look for signs of keratoconus in routine eye exams.