Diagnosing keratoconus
Your ophthalmologist may use a number of tools to make a diagnosis of keratoconus, including:
- A slit lamp, which combines an intense light source with a microscope to examine your eyes
- A keratometer to measure the curvature of the cornea
- Corneal topography, which creates a 3D model of the cornea to detect any subtle changes.
Treating keratoconus
In the early stages of keratoconus, the only treatment required may be prescription glasses to correct your vision. Unfortunately, this is a progressive condition so your vision will eventually deteriorate, sometimes quite rapidly.
Below are some of the other keratoconus treatments your ophthalmologist may recommend.
Contact lenses
Rigid (hard) or hybrid contact lenses may be prescribed and are particularly effective in treating keratoconus for a period of time. These are made from a special material that allows the contact lens to mask the abnormal shape of the cornea and improve vision. However, contact lenses do not stop the condition from progressing and will eventually become ineffective.1
Corneal ring segments
This type of keratoconus surgery involves the insertion of clear plastic segments into the cornea. These segments are designed to reshape the front surface of the eye, thus correcting refractive errors caused by keratoconus.
Corneal ring segments are reserved for advanced cases of corneal ectasia, where the patient’s vision is not correctable with glasses or contact lenses.
Corneal collagen cross-linking
Corneal cross-linking surgery can effectively stop the progress of keratoconus.2 It involves a combination of collagen and riboflavin (vitamin B2), which are activated by ultraviolet light to significantly strengthen the rigidity of the cornea.
First, the top layer of the cornea (epithelium) is gently removed. The cornea is then saturated with collagen and riboflavin, and UV light applied to activate the solution. This causes the collagen strands to bond across the cornea and strengthen it. Early treatment with collagen cross-linking can slow or sometimes even stop the progression of keratoconus.
The procedure takes approximately one hour and is performed as an outpatient procedure in the clinic. Patients usually experience some mild discomfort in the immediate post-operative period.
Following treatment, the patient is fitted with a contact lens that stays in place for up to three days. Antibiotic drops are applied to the treated eye until the surface of the eye has healed. This is followed by steroid drops for approximately 5 to 6 weeks.
Corneal collagen cross-linking for keratoconus attracts a Medicare rebate. Contact your nearest Vision Eye Institute clinic for more information.
Corneal transplantation (keratoplasty)
This will only be suggested if all other keratoconus treatments options have been exhausted. About 10–20% of patients eventually require corneal transplantation.3
There are two types of corneal transplants – partial-thickness and full-thickness (or penetrating). It is usually the latter that is recommended for patients with keratoconus.
A corneal transplant is a complex procedure and requires admission to a day surgery. It is generally performed under local anaesthetic, with the option of a sedative. During the procedure, your surgeon will cut out the abnormal section of the cornea and replace it with donor cornea, which will be stitched into place. The stitches will be removed at a later date. Your own corneal cells will gradually grow and fuse to the donor tissue. Full recovery from this type of keratoconus surgery can take up to a year.
References
1. Keratoconus Australia. Contact lenses & spectacles [Internet]. Australia: Keratoconus Australia; [date unknown] [cited 2021 Jan 27]. Available from: https://www.keratoconus.org.au/treatments/contact-lenses/
2. Keratoconus Australia. Corneal crosslinking [Internet]. Australia: Keratoconus Australia; [date unknown] [cited 2021 Jan 27]. Available from: https://www.keratoconus.org.au/treatments/corneal-collagen-crosslinking/
3. Godefrooij et al. Nationwide reduction in the number of corneal transplantations for keratoconus following the implementation of cross-linking. Acta Ophthalmol. 2016 Nov;94(7):675-678. doi: 10.1111/aos.13095. Epub 2016 May 23. doi: 10.1111/aos.13095