What is Keratoconus?

Keratoconus is a condition that affects the cornea (surface) of the eye. The cornea is the clear, outer layer of the eye, mainly made up of water and collagen. Keratoconus causes the cornea to become thin creating an irregular cone-shaped surface resulting in poor focussing and blurred vision. When the cornea becomes thin it starts to lose its normal integrity and scarring may occur.  

Keratoconus is usually diagnosed in people in their teens or early twenties, generally, their astigmatism will increase, and they will experience blurred vision. During the early stages, specialist contact lenses are usually worn to help prevent the progression.

How Does Keratoconus Affect Vision?

Keratoconus is a progressive condition and is usually first diagnosed by an optometrist during an eye examination. During the earliest stages, vision may seem unaffected, but as it progresses, Keratoconus causes blurred vision; and if left untreated, corneal scarring can occur, stopping the eyes from focusing correctly. Even in advanced Keratoconus, contact lenses can usually be used to correct the vision, but if scarring does occur, surgery may be required.

What Are The Symptoms of Keratoconus?

Most people with Keratoconus are unaware they have the condition. The earliest symptom is usually blurred vision that is not easily fixed with standard glasses or contact lenses.

Other symptoms of Keratoconus can include:

• Eye irritation

• Headaches

• Increased sensitivity to bright light

• Difficulty seeing at night

• Glare and halos around lights

How Do We Diagnose & Treat Keratoconus?

During your Eye Examination, if your clinician suspects that you may have keratoconus we would recommend performing Corneal Topography to confirm.

After this, we may refer to a Corneal Consultant, to discuss ant surgical options, or for those who are eligible, would start with specially designed spectacle lenses to treat the visual symptoms of Keratoconus.

For some patients, spectacle lenses may not provide you with the best clarity of vision, in this case, specialist contact lenses would be the better option. Most people with Keratoconus would require RGP or Scleral contact lenses and not the usual soft contact lenses.

What Is The Process to Diagnose &Treat Keratoconus?

Eye Refraction

In this test, your Optometrist will use specialist equipment to determine the refractive power of your eye. Keratoconus is characterised by a high amount of astigmatism.  At Eye Academy, your Optometrist will ask you to look through a device that contains wheels of different lenses (phoropter) to help judge which combination gives you the sharpest vision. Your Optometrist will use a hand-held instrument (retinoscope) to evaluate the refractive power of your eye. This will be followed by a precise and accurate subjective refraction.

Video Slit-lamp Examination

In this test, your Optometrist will use a low-powered microscope which will direct a vertical beam of light on the surface of your eye. Your Optometrist will evaluate the shape of your cornea and look for other potential problems in your eye. Your Optometrist will use an orange dye to assess the dryness and shape of your eye.

Digital Corneal Mapping

Special photographic tests, such as corneal topography, record images to create a detailed shape map of your cornea. Corneal topography can also measure the thickness of your cornea. Corneal topography can often detect early signs of keratoconus before the disease is visible by slit-lamp examination. The specialised imaging device also performs keratometry. Corneal topography is used to help measure the shape and power of the cornea. It allows your Optometrist not only to fit contact lenses to match the power and shape of the cornea, but it also helps them to evaluate the intricacies of the contact lens's relationship with the ocular surface.

Posterior Pole Examination

Even though Keratoconus affects the front of your eye, the posterior part of your eye (optic nerve, macula, and fundus) also needs to be carefully examined to ensure that no other co-existing pathology is present. At Eye Academy, your Optometrist will use OCT imagining and a volk lens (high-powered lens) to examine the posterior part of your eye.

Management

Depending on the results from your corneal topography, your Optometrist will explain the most appropriate options to manage your condition.

Glasses: Our highly skilled dispensing Optometrist will help you select the most appropriate frames and lenses to give you the best possible vision. Glasses can correct blurry or distorted vision in early keratoconus. But people frequently need to change their prescription for spectacle glasses or soft contact lenses as the shape of their corneas change.

Rigid Gas Permeable Lenses: Hard (rigid, gas permeable) contact lenses are often the next step in treating more-advanced keratoconus. Hard lenses may feel uncomfortable at first, but many people adjust to wearing them and they can provide excellent vision. This type of lens is specifically designed to fit your cornea. There are a number of several types of RGP lenses, but your Optometrist will use the results from your topography to fit you with the best-fitting lens. Remember every rigid gas permeable lens is bespoke and tailored to your eye.

Scleral Contact Lenses: These lenses are larger in diameter in comparison to RGP lenses. The lens sits on the sclera (white part of the eye). Scleral lenses are mostly fitted in hospital eye services but at the Eye Academy, we provide this service in practice. These lenses are typically used to fit very irregular-shaped corneas.

Contact Lens Teach

After fitting your eye with your bespoke specialist lens. Your Optometrist will teach you how to insert and remove your contact lens. Hard lenses require a different and personalised teaching regime. Due to the nature of the lenses, they require a more specific handing and cleaning regime.

It is important to remember if you are using rigid or scleral contact lenses, the lens needs to be fitted by a Specialist Optometrist with experience in managing keratoconus. A poorly fitted contact lens can cause damage to your cornea.

Keratoconus is a progressive condition. So, you will need to have regular check-ups with topography to monitor progression.

Is there any other treatment for Keratoconus?

 It is important to note that there is currently no treatment that can reverse the effects of keratoconus on the cornea.

There is however a treatment option that can stop or slow the progression of Keratoconus once detected. Collagen Cross-linking of the Cornea has changed the way keratcounus has been managed over the last decade. Ophthalmologists are now able to offer this as a treatment once progression has been noted. There is however a threshold of corneal thickness, where if the cornea is thinner it cannot be safely performed, it is therefore imperative that Keratoconus is carefully monitored especially in the early stages.

If keratoconus progresses to a stage where contact lenses no longer provide adequate vision then a Corneal Transplant is the final option. For keratoconus, there are 2 types of transplant depending on the depth of scarring, these are Deep Anterior Lamellar Keratoplasty (DALK) or Penetrating Keratoplasty (PK).