Irregular Cornea
Ectasias
Corneal ectasia is a progressive condition that leads to protrusion and thinning of the cornea, the front part of the eye. In early stages corneal ectasias can be corrected with glasses; but if the condition worsens, specialty contact lenses often offer optimal vision correction.1 There are several different classifications of corneal ectasias. The two most frequently encountered types are keratoconus and pellucid marginal degeneration. Keratoconus is the most common corneal ectasia, with a prevalence of approximately 54 per 100,000 people in the United States.1 Risk factors for developing corneal ectasias include environmental and genetic factors. Eye rubbing, history of atopic conditions, and family history are associated risk factors to developing a corneal ectasia.1
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TYPES OF CORNEAL ECTASIAS |
| Keratoconus |
| Pellucid Marginal Degeneration |
| Keratoglobus |
| Post-LASIK Ectasia |
Because of the effects of corneal ectasias on vision, this condition can negatively influence quality of life. Patients with corneal ectasias should be followed closely by their eye care providers for progression of the condition and for updates to their specialty contact lenses for the most optimal vision correction. Depending on the stage of the corneal ectasia, patients can be fit in specialty soft, corneal gas permeable (GP) or scleral contact lenses. Ask your eye care provider which option may be best for you.
Post Corneal Transplant
Corneal transplantation is a procedure that removes diseased or damaged corneal tissue and replaces it with a transparent donor corneal graft. A corneal transplant may be considered for patients with irreversible damage to the cornea. Indications for corneal transplant include but are not limited to: corneal ectasia, corneal scarring, corneal dystrophy, infectious keratitis, and corneal ulceration and perforation.2 There are a handful of different corneal transplant procedures. Ask your eye care professional which procedure is best if you feel you may be a candidate for corneal transplant.
Even after successful corneal transplantation, it is usually still necessary to provide some form of vision correction. Because of the cornea’s irregularities after surgery, glasses sometimes cannot offer the best vision. Specialty contact lenses can offer optimal vision for corneal transplant patients. Corneal gas permeable (GP) and scleral lenses are great options for corneal transplant patients.
Figure 1. A photo of an eye following a corneal transplant fit successfully with a scleral contact lens. The scleral contact lens improved this patient’s vision from 20/50 to 20/20.
Post Refractive Surgery (LASIK, PRK, RK)
In most cases, patients have great results after refractive surgery, but a small percentage of patients experience some complications. Over or under-correction of refractive error may be a complication after surgery. In many cases, patients have a repeat treatment done to correct this. In rare cases, the patient may not be an acceptable candidate for re-treatment. In this case, the patient must rely on glasses or contact lenses to correct their vision.
Another complication of refractive surgery includes post-refractive surgery ectasia. Corneal ectasia after refractive surgery causes steepening of the cornea, irregular astigmatism, and sometimes progressive increase in near-sightedness.3 Corneal gas permeable (GP) and scleral lenses are great specialty contact lens options for patients with post-refractive surgery ectasia.
Radial keratotomy, also known as “RK”, was a refractive surgery commonly performed over twenty years ago. Due to improvement in technology and refractive surgery methods, radial keratotomy is no longer a recommended refractive surgery option. Some RK patients have trouble seeing clearly because the surgery can cause irregular amounts of astigmatism and/or corneal scarring on the eye’s surface that can lead to blurry vision and visual distortions. Corneal gas permeable (GP) and scleral lenses are great specialty contact lens options for post-RK patients.
If you have had refractive surgery in the past and are experiencing visual changes, ask your eye care professional which contact lens option may be best suited for you.
Contributed by: Dr. Sam Schlesman
References
- Lim, L. and Wen Ling Lim, E. Current perspectives in the management of keratoconus with contact lenses. Eye. 2020; 34:2175-2196.
Available at: https://pubmed.ncbi.nlm.nih.gov/32641797/ - Zhou, Y., Wang, T., Tuli, S., et al. Overview of Corneal Transplantation for the Nonophthalmologist. Transplantation Direct. Feb 2023; 9 (2):p e1434.
Available at: https://pubmed.ncbi.nlm.nih.gov/36700069/ - Wolle, M., Randleman, J.B., and Woodward, M. Complications of Refractive Surgery: Ectasia after Refractive Surgery. Int Ophthalmol Clin. 2016; 56(2): 129-141.
Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC4780337/