Corneal Warpage: Not Just
for Rigid Lens Wearers

BY ROBERT A. RYAN, O.D., & PUSHPA JACOB, M.D.
SEPT. 1996

Diagnosticians will typically consider corneal warpage in their differential diagnoses of contact lens complications in long-term PMMA wearers. On occasion, we encounter this condition in ill-fitting rigid gas permeable lenses. This case illustrates that contact lens-induced corneal distortion can also occur in patients who wear hydrophilic lenses, and sometimes in these cases keratometry can be misleading.

THE ONLY COMPLAINT: DECREASED NEAR ACUITY

Our patient, a 38-year-old female, complained of decreased near visual acuity with her current hydrophilic contact lenses and her spectacles prescribed three months prior. She denied any discomfort, lens intolerance or decreased wearing time.

Ocular history included annular tint hydrophilic lens wear 10 hours per day for seven years. She alternated between AOSept and ReNu multipurpose solutions nightly, and did not use surfactant daily cleaner or enzymatic tablets regularly. Her current contact lenses were 18 months old. She had no history of ocular trauma or surgery. Systemic and family health history were excellent with no allergies noted; she was not taking systemic medications. We had seen the patient three months earlier with near point complaints. At that time, refraction showed a decrease in myopia from -5.75 sphere OU to OD -4.75 -0.75 x 015 and OS -4.50 -1.50 x 005 with 20/20 acuity OU. Contact lens parameters were Softmate B green 8.7/14.3 -5.75 OU.

CONFIRMING THE DIAGNOSIS

Entering visual acuities with contact lenses were OD 20/25, OS 20/40. Slit lamp examination showed a slightly soiled, well-centered hydrophilic lens with 0.25mm movement OU, and no evidence of epitheliopathy, edema, stria or limbal injection. Overrefraction showed no improvement in acuity, and static retinoscopy revealed a central, well circumscribed nipple-type distortion to the reflex. Keratometry measured OD 46.00 @ 07/47.12 @ 97, OS 46.12 @ 174/47.50 @ 84; funduscopic examination was benign. Videokeratoscopy confirmed significant central distortion while surface regularity and surface asphericity indices were significantly elevated indicating irregular astigmatism/corneal warpage. The patient was unable to function with her current spectacles, so we prescribed Surevue 8.8/14.0 -5.75 OU as a temporary measure.

After 13 days, acuity was OD 20/15^-, OS 20/20. Refraction OD: -4.75 sphere 20/15^-, OS -4.50 sphere 20/20⁺. Biomicroscopic evaluation revealed that the lenses were well-centered with excellent movement. The overrefraction was +1.00 OD 20/20, +1.25 OS 20/20. The anterior segment remained normal and quiet, and retinoscopy showed a normal, crisp spherical reflex. Computerized topography demonstrated a significant reduction in central irregularities (Figs. 1 & 2) confirmed by surface regularity and surface asphericity indices. We noted some inferior steepening without any associated clinical signs of keratoconus.

FIG. 1: RIGHT EYE IMMEDIATELY FOLLOWING REMOVAL OF CONTACT LENS.

FIG. 2: RIGHT EYE AFTER TWO WEEKS OF SUREVUE CONTACT LENS WEAR.

A RETURN TO GOOD VISION

We modified the contact lens parameters to Surevue 8.8/14.0 -4.75 OD, -4.50 OS with excellent subjective response, 20/20 J1 OU. Two weeks later, the patient continued to do well and we advised her to update her spectacles at that time. CLS

Dr. Ryan is in a group practice in Rochester, N.Y. Dr. Jacob worked with Dr. Ryan while on a research fellowship. She is now at Christian Medical College Hospital, Vellore, India.