Keratoconus

What is Keratoconus?

Keratoconus is a progressive condition where the cornea at the front of the eye stretches into a distorted cone shape, causing blurred vision due to irregular astigmatism. “Kerato” is the Latin word for cornea, and “conus” means conical shape.

To demonstrate, we took this photo with our slit lamp microscope camera. In this image the eye on the left is one of our Custom Eyecare staff members, whereas the eye on the right is one of our keratoconic patients. The differences in the corneal contour highlight the changes in keratoconus.

Keratoconus often first appears in the teens or twenties, although in some cases it presents in young children. It often progresses for 10-20 years and then stabilises, although everyone is different. The cause is not fully understood but it does appear to be associated with allergies and excessive eye-rubbing, and also there is a genetic (hereditary) component.

In early keratoconus, vision changes may be mistaken for regular astigmatism, and glasses or soft contact lenses may still provide good vision. Commonly in early keratoconus, vision changes are frequent and you may be told by your previous optometrist that your eyesight has worsened and you simply need stronger glasses.

How is Keratoconus Diagnosed?

Screening for keratoconus is important in any young person with astigmatism, frequent changes in vision, or a family history of keratoconus. The only way to truly diagnose keratoconus is to have a detailed “contour map” of your cornea, called corneal topography.

Ultimately, like a surveyor uses a topographer to map out the hills and valleys in a landscape, corneal topography allows us to map out the hill and valley in the cornea. Beyond diagnosis, this mapping is vital to monitor for progression. Historically, there was no treatment to slow progression. Nowadays, careful reviews to exclude keratoconus progression are hugely important. If there are any signs that keratoconus is getting worse, or the cone is steeping, prompt referral to an eye surgeon is necessary to confirm if surgical options to prevent further deterioration should be considered.

Research shows that if you have keratoconus, up to 50% of your close family members may also have suspicious corneal changes, detectable by topography. Early detection & awareness of keratoconus in family members means better, more customised eyecare and better outcomes.

If you know, or even suspect, that you have keratoconus or a related condition we are happy to welcome you to our practice for an initial consultation and a discussion of your various options.

Contact us to arrange your keratoconus assessment and comprehensive eye & vision check.

Keratoconus Options to Improve Vision

Typically keratoconus patients don’t see well with glasses. The corneal distortion causes an irregular warped effect on your vision and even though you will see better in glasses than with no glasses at all, patients often experience poor quality vision in spectacles with lots of ghosting and halos.

Any soft contact lens is simply going to drape over the cone and not really help us improve the sight, or regularise the distortions. If visual quality is poor in glasses, the best way to provide clear vision is with a custom made Rigid Gas Permeable (RGP) contact lens, designed especially for keratoconus.

The aim of fitting a rigid material contact lens for keratoconus is to create a new “regular” surface which delivers stable and great quality vision, is comfortable enough to wear most days, and does not cause any negative effects on the ocular surface.

Which Contact Lens Option is Best?

Custom made Rigid Gas Permeable (RGP) contact lenses, commonly called hard lenses, come in a few options. 

1. Corneal Rigid Gas Permeable contact lens (RGP)
2. Piggyback Rigid Gas Permeable contact lens
3. Scleral and Miniscleral Rigid Gas Permeable lens
4. Hybrid contact lens

Again, corneal topography maps are vital here as they provide accurate customised information to ensure successful keratoconus RGP contact lens fitting. Topography allows us to map the shape, size and position of the corneal distortions to select the most appropriate lens type for each individual eye.

This concept applies to RGP contact lens fittings for other reasons besides Keratoconus. Customised specialty contact lens fitting can be considered for any corneal condition including astigmatism, Pellucid Marginal Degeneration (PMD), Dry eye, Intacs or Kerarings, corneal grafts and corneal scarring. 

Beyond the shape, size and position of the cone in the cornea, there are other factors that determine which contact lens option is best for you. Your motivation, your work environment, your lifestyle, your hobbies, sporting activities, and whether we are considering fitting one eye or both eyes with contact lenses are all important considerations.

Corneal RGPs

Custom made Rigid Gas Permeable (RGP) contact lenses, commonly called hard lenses, are typically 8-11mm diameter and rest on the cornea. RGP refers to the material of the contact lens. It has a rigid structure so on first glances it may seem similar to glass or perspex. However, unlike glass or perspex, gas permeable means it allows oxygen to pass through the lens material. This oxygen permeability is vital for providing the cornea with nutrition and ensuring optimal corneal health. 

Keratoconus Corneal RGP designs include: Rose K, Rose K2, KBA, Epicon, Kera, Centra PGA, Keracon and Marconus. 

Piggyback RGPs 

If you hear someone say “piggyback” contact lenses it simply means when a corneal rigid lens (RGP) is placed on the eye, on top of a soft contact lens. So the two different lens options piggyback off each other. 

Scleral Contact Lenses

The sclera is the fancy name for the whites of our eyes. A scleral lens is a rigid contact lens that does not actually touch the cornea, and lands on the sclera. The analogy we use to explain scleral lenses is that conventional corneal RGPs are designed to “resurface” a distorted road to restore vision, whereas a scleral lens is designed to bypass the distortions and build a new smooth bridge up over the top to restore sight. Miniscleral and scleral lenses completely vault over the cornea and are significantly larger than any of the other contact lens options for keratoconus. 

Designs include Capricornia ICD (KATT), Forge Eyespace, Gelflex and Zenlens scleral lenses.

Hybrid Contact Lenses

As the name suggests, a Hybrid lens is a blend of both a rigid and soft contact lens. Hybrid lenses are a single lens with the two materials fused together. The central portion of the contact lens is made of a rigid material, and the surrounding skirt of the lens is made of a soft lens material. 

Designs include Synergeyes ClearKone & Ultrahealth hybrid lenses. 

Specialty Contact Lens Fitting for Keratoconus

Keratoconus contact lens fitting at Custom Eyecare involves an initial baseline eye examination in our Darby Street practice where we check the overall health of your eyes, measure your vision, map your corneas, and give you a recommendation of your best vision correction option (glasses, soft lenses, or custom rigid lenses).

At Custom Eyecare we have skill and experience fitting a range of contact lens options for patients with keratoconus. We offer Customised specialty contact lens fitting for keratoconus, corneal grafts and scarring using corneal, RGP, piggyback, scleral & hybrid contact lenses. Our optometrists are all members of the Cornea and Contact Lens Society of Australia

Specialty contact lens fitting is an advanced area of optometry practice and something that our optometrists have a special interest in, and lots of experience. We regularly receive referrals from other optometrists and eye surgeons for our expertise in specialty contact lens fitting.

The best type of lens for an individual patient depends on how advanced the keratoconus is, and on the shape and type of cone in each eye. 

If you proceed to speciality contact lens fitting, including rigid lens (RGP) fitting, we often calculate the best lens options for you based on your topographic data from your corneal maps. Then, we assess several pairs of ‘trial or diagnostic’ lenses on your eyes before ordering your own custom made contact lenses. Commonly, even your custom made lenses need to be modified or ‘tweaked’ after trying them out, and this is covered by your lens warranty. 

It’s normal for keratoconus lens fitting to involve a number of visits in order to achieve a good lens fit, and this is covered by your contact lens fitting fees.

Surgical Treatments for Keratoconus

Collagen Cross-linking & Corneal Grafts

If you’ve been diagnosed with keratoconus it’s natural to feel concerned, but the right eyecare and expertise can usually provide you with a lifetime of good useful vision. 

Historically, there was no treatment for keratoconus, and when the cornea got too thin or steep, patients required a corneal graft or corneal transplant. Nowadays, with advancing technology and treatments, keratoconic progression can be treated and often the conical distortion doesn’t advance to the stage of needing a corneal graft. Many keratoconus patients achieve good vision for many many years using custom RGP contact lenses, without ever needing a corneal graft.  Anyone who has been diagnosed with keratoconus should strictly avoid eye rubbing.

A surgical procedure called corneal cross-linking (CXL), using riboflavin, may be used to slow down progression. Both corneal grafts and collagen cross-linking are the domain of a Corneal Ophthalmologist or eye surgeon. We work closely with many ophthalmologists and are able to offer advice and referral for surgical treatments where necessary. 

To learn more about Keratoconus and Corneal Grafts, watch this video:

Contact us to arrange your keratoconus assessment and comprehensive eye & vision check.