IMPROVED TECHNIQUE OF CIRCULAR KERATOTOMY FOR THE CORRECTION OF CORNEAL ASTIGMATISM

BACKGROUND: Based on Gauss' law governing the comparison of hyperbaric pressure in the eye and atmospheric pressure, the authors present a p rocedure to correct astigmatism. The present paper describes an improv ement of a technique for circular keratotomy that was published previo usly. METHODS: We present data on a consecutive series of 32 eyes with a mean corneal astigmatism of 4.66 diopters (D) (range -2.25 to -6.00 D) with a variety of clinical diagnoses. The astigmatic cornea was tr ephined with a diameter of 7 mm and a depth of 300 mu m. After deepeni ng of the trephination with a diamond knife to 550 mu m over the steep er semimeridians, the intraocular pressure created a rounding of the c ornea. The amount of astigmatic correction and extent of deepening wer e controlled intraoperatively with a keratoscope. No sutures were plac ed. RESULTS: In 32 consecutive eyes, corrections were between 50 and 9 0% of the initial cylindrical values after 1 week to 1 month. In 29 ey es (91%), the results obtained remained stable during a 1-year follow- up; in two eyes (6%), the 1-month results worsened by more than 1.00 D and in one eye (3%), results improved by more than 1.00 D. There were no complications during or after surgery. Wound gaping resulting in e pithelial plugs did not occur. No patient lost one or more lines of sp ectacle-corrected visual acuity, but 13 eyes (40%) gained one or more lines. CONCLUSION: The technique of correcting corneal astigmatism by trephining to a depth of 300 pm, with deepening of the wound to 550 pm along the steep meridian and using no sutures can correct up to 10.00 D of astigmatism with reasonable stability.