• Twenty-five cadaver eyes were used to study the effect of paired arcuate keratotomy on corneal astigmatic changes. Paired arcuate incisions placed at optical zones of 5, 6, 7, 8, and 9 mm were progressively lengthened from 45° to 60° 90°, and, finally, 120°. The corneal flattening in the meridian centered over the incisions and the corneal steepening 90° away were quantified with each successive lengthening. Linear regression analysis showed a direct linear relationship of corneal astigmatic change (sum of corneal flattening and steepening, or ΔK) to decreasing optical zone size as measured in millimeters and increasing incision length as measured in degrees. The ΔK value ranged from 2.65 ± 1.07 diopters to 22.05 ± 3.55 D. The flattening/steepening coupling ratio mean was 1.47 ± 0.41. Progressively longer paired arcuate incisions produced a predictable and titratable corneal flattening in the meridian centered over the incisions and a slightly smaller corneal steepening 90° away, making the procedure ideal for mixed astigmatism.
Duffey RJ, Jain VN, Tchah H, Hofmann RF, Lindstrom RL. Paired Arcuate KeratotomyA Surgical Approach to Mixed and Myopic Astigmatism. Arch Ophthalmol. 1988;106(8):1130-1135. doi:10.1001/archopht.1988.01060140286043