Greatly improved outcomes for Keratoconus patients

The introduction of Topography-guided Custom Ablation Treatment (T-CAT) at the start of Keratoconus treatment to improve the central corneal symmetry, without attempting to correct other optical defects has greatly improved the visual outcomes for patients with this condition.

Keratoconus is a fairly uncommon non inflammatory eye condition that affects the cornea (the transparent window at the front of the eye). It causes changes within the structure of the cornea making it weaken and thin resulting in ‘cone-shaped’ bulging.

Accuvision have found that by not attempting to correct the whole optical defect of the eye caused by the effects of keratoconus, the T-CAT treatment offered at Accuvision can be kept to a small degree of ablation with the maximum depth of tissue loss typically being less than 50 microns. The C3-R® cross-linking treatment is applied immediately after the laser treatment. Any residual spherical or regular astigmatic optical defect remaining after the T-CAT treatment can then be corrected by contact lens wear or by phakic intra-ocular lens implantation.

Symptoms of Keratoconus

Keratoconus leads to myopia (short sight) and, if the steepening is uneven, also astigmatism (distortion of vision). Keratoconus symptoms usually start with blurring of vision and people usually seek corrective lenses at first for driving or reading. Keratoconus at this stage is difficult to differentiate from other more common vision defects. As keratoconus develops, visual acuity can diminish very quickly in some cases. Changes can occur more rapidly in one eye than another. Keratoconus can also cause eye irritation, sensitivity to light but usually no pain. Visual distortion can become difficult to correct. Severe extasia and central corneal scarring in advanced keratoconus can significantly limit the amount of visual rehabilitation that can be achieved by rigid lenses. There is also growing evidence to suggest that repeated trauma caused by the wearing of rigid contact lenses may in some cases be responsible for the acceleration of the condition.

How is Keratoconus C3-R® treatment given?

The keratoconus C3-R® treatment is carried out with topical anaesthesia (eye drops). The surface epithelial cell layer is removed from the central part of the cornea, and the riboflavin drops applied. Once the riboflavin has penetrated well into the eye, the UV light is focused onto the central area of the cornea for 30 minutes.

Finally a bandage soft contact lens is applied. The contact lens is worn for three or four days until the surface epithelial cell layer has re-grown. During the first few days the eye will be sore and watery. Sometimes there is slight haziness under the epithelial layer for the first few months after treatment, but the vision stabilises within a month or so of the treatment.

C3-R® is a registered trademark of Boxer Wachler Vision Institute.