Contact Lens Case Reports
New Custom Soft Lens for Keratoconus
By Patrick J. Caroline, FAAO, & Mark P. André, FAAO
Our patient is a 45-year-old man with a 20-year history of keratoconus, involving predominately the right eye. He underwent uneventful Intacs surgery to the right eye in 2003. He was wearing a toric soft contact lens on the right eye (visual acuity 20/200, PH 20/40) and a spherical soft lens on the left eye (visual acuity 20/20). His wearing time was approximately 14 hours a day.
Keratometry readings were 50.00 @ 002 / 52.12 @ 092 OD and 43.87 @ 179 / 44.37 @ 089 OS (Figure 1). Optical coherence tomography measured sagittal heights of 3,800 microns OD (over a chord of 14.5mm) and 3,610 microns OS, a difference of 190 microns between the two eyes, which is equivalent to the height of approximately 2.5 human hairs.
We decided to fit the patient's right eye with the new KeraSoft IC soft contact lens (Bausch + Lomb/Art Optical).
Figure 1. Corneal topography of the patient's right and left eyes.
Custom Soft Lens Option
The KeraSoft IC lens comes in an eight-lens diagnostic set and is designed to fit all stages of keratoconus and other irregular corneas, such as pellucid marginal degeneration, post keratoplasty and post refractive surgery. The lens incorporates a dual aspheric (anterior and posterior) design with a Sector Management Control system, which allows the independent adjustment of the lens periphery in two sectors, i.e., above and below. Each diagnostic lens has a center thickness of 400 microns and incorporates a single rotation marker at 6 o'clock to aid in the orientation of any residual cylinder that may be present (Figure 2). The lens is manufactured in the new Contamac Definitive material which is a latheable, non-surface-treated, daily wear, silicone hydrogel with a Dk of 60 and a water content of 74 percent.
Figure 2. Optical coherence tomography image of the Kerasoft IC lens on the patient's right eye.
We fitted the patient's right eye with an 8.6mm base curve, 14.5mm diameter plano lens, which we evaluated for centration, movement and rotation (Figure 3). With an over-refraction of –2.75 –2.00 x 017, the patient achieved a stable endpoint acuity of 20/30.
Figure 3. The KeraSoft IC lens on the patient's right eye; note the rotation marker at approximately 6 o'clock.
Merging Advanced Technologies
The idea of a custom soft contact lens for keratoconus dates back to January 1979 when the U.S. Food and Drug Administration approved the Flexlens soft lens “for the correction of any atypical ametrope.” The recent resurgence of this modality has been made possible through the merging of advanced technologies in the areas of lens designs, materials and manufacturing. CLS
Patrick Caroline is an associate professor of optometry at Pacific University. He is also a consultant to Paragon Vision Sciences. Mark André is an associate professor of optometry at Pacific University. He is also a consultant to CooperVision.