A Case of Cyclic Keratoconus
BY BEZALEL SCHENDOWICH, OD, FIACLE
Keratoconus is an inherited, non-inflammatory, progressive degeneration of the cornea resulting in corneal thinning, distortion and the generation of high degrees of irregular astigmatism. The visual disturbances of as many as 90 percent of all keratoconus patients are successfully managed with eyeglasses or contact lenses. Some 10-to-15 percent of keratoconus-affected eyes progress to the need for penetrating keratoplasty.
The asymmetric and generally inferior steepening of keratoconus corneas usually begins in the teen years. These changes have been documented in younger children, and we have also observed several cases in which the effect of keratoconus did not become apparent until later decades.
A Peculiar Case
In our clinic we currently see several hundred keratoconus patients. Over the last few years we had the opportunity to treat a 30-year-old man whose corneal curvatures have progressed and regressed cyclically over time. His left cornea peaked and troughed four times over a 12-month period (Figure 1), ranging in the flat meridian from 44.60D to 47.70D and in the steep meridian from 45.00D to 48.90D. Figure 2 shows the topography image of the patient's left eye on Nov. 12, 2006. Figures 3 through 6 demonstrate some of the variations in his corneal topography in the eight months that followed.
Figure 1. Cyclic changes of Sim-K readings in diopters.
Figure 2. Left eye image from Nov. 12, 2006. In this and the following images the scale is standardized to allow for easy comparison and the axis marker is set to cut the corneal profile most emphasizing the variation in topography across the cone. This system allows for ready comparison of the corneal topography over the period studied.
Figure 3. Left eye topography, Nov. 26, 2006.
Figure 4. Left eye topography, Feb. 7, 2007.
Figure 5. Left eye topography, May 14, 2007.
Figure 6. Left eye topography, June 6, 2007.
Several times during the course of the year I attempted contact lens fittings, and each time his eyes confounded my efforts by changing shape before the lenses arrived.
This patient is a scholar whose occupation requires that he read from morning to night. He is satisfied with the quality of his reading vision, so we agreed for the time being to not complicate his life with either eyeglasses or contact lenses, as their prescriptions are likely to change with the variations of his corneal shapes. I did recommend that he come in from time to time to allow us to follow his condition.
A further consideration that we discussed is corneal collagen cross-linking with riboflavin. This treatment might help to strengthen, firm and increase the rigidity of his corneas, allowing for more stable vision and a more stable prescription for vision correction. CLS
Dr. Schendowich is a Fellow of the International Association of Contact Lens Educators, an adjunct assistant clinical professor of optometry at SUNY-Optometry in the optometry clinic at the Sha'are Zedek Medical Center, Jerusalem, Israel, and he is a Member of the Medical Advisory Board of the National Keratoconus Foundation, USA.