Clinical management of keratoconus. A multicenter analysis.

The clinical management of 746 eyes in 417 patients referred for keratoconus from January 1984 through January 1988 was retrospectively analyzed. In 357 patients, 554 eyes (74%) did not require surgery and were managed with contact lenses or spectacles, 156 eyes (21%) in 137 patients either underwent penetrating keratoplasty (PK) (140 eyes) or surgery was recommended (16 eyes), and 36 eyes (4%) in 34 patients underwent epikeratoplasty. Comparing baseline and final examination findings, the nonsurgical group showed a significant improvement in average best-corrected visual acuity from 20/30 to 20/25, the PK group from 20/70 to 20/25, and the epikeratoplasty group from 20/40 to 20/30. Average keratometry was unchanged in the nonsurgical group, but decreased by 10.7 diopters (D) for the PK group and 6.5 D for the epikeratoplasty group. Corneal cylinder was unchanged in the nonsurgical group, whereas there was a reduction of the percentage of eyes with indeterminant cylinder from 55 to 2% in the PK group and from 36 to 0% in the epikeratoplasty group. Previous contact lens history, best-corrected visual acuity of 20/50 or worse, and average keratometry of 55 D or greater at baseline were associated with a significant risk for PK. No baseline variables were associated with significant risk for epikeratoplasty, suggesting that this group was similar to the nonsurgical group, except for contact lens intolerance. The nonsurgical management of keratoconus continues to play a predominant role in the management of this disorder in a referral population.

Corneal endothelial polymegathism induced by PMMA contact lens wear.

Central corneal endothelial photographs were taken for 15 persons who had worn polymethylmethacrylate (PMMA) contact lenses for 7-15 yr and for a nonwearing control group matched for age and sex. An individual cell area analysis was made from the cell tracings. Significant endothelial polymegathism was noted for each member of the contact lens wearing group. PMMA wearers showed an average coefficient of variation of 0.445 for central corneal endothelial cell area compared to 0.245 for nonwearers (81.6% increase in polymegathism). The average maximum/minimum cell size ratio was 8.06 for the PMMA wearers vs 3.42 for the nonwearing control group. The frequency distributions for the cell areas reveal that the contact lens wearer develops cells that are much smaller and larger than normal.