Corneal Optical Quality Following Sub 1.8 mm Micro-Incision Cataract Surgery vs. 2.2 mm Mini-Incision Coaxial Phacoemulsification.

PURPOSE

To study and compare the effects of the micro-incision cataract surgery (MICS-sub 1.8 mm) and miniincision coaxial phacoemulsification (2.2 mm) on the optical quality of the cornea characterized in terms of corneal aberrations.

MATERIALS AND METHODS

Fifty eyes underwent MICS and 50 mini-incision phacoemulsification, by the same surgeon. Both types of cataract surgery were performed using low ultrasound power and through a clear corneal incision, placed on the steepest corneal meridian ranging from 1.6 to 1.8 in MICS (Group I) and from 2.12 to 2.3 mm in mini-incision coaxial phacoemulsification (Group II). Seidel and Zernike aberration coefficients and RMS values were obtained for a 6-mm pupil preoperatively and one month after surgery.

RESULTS

THE CORNEAL ASTIGMATISM DID NOT SHOW STATISTICALLY SIGNIFICANT CHANGES IN EITHER OF THE TWO GROUPS: (MICS: -0.73 +/- 0.63, -0.65 +/- 0.53 D, P = 0.25), (mini-incision phacoemulsification; -1.21 +/- 1.52, -1.00 +/- 1.19 D, P = 0.12). The total RMS remained unchanged after MICS (1.77 +/- 1.7, 1.65 +/- 1.3 mum, P = 0.18) and mini-incision phacoemulsification (2.00 +/- 1.87, 2.09 +/- 1.8 mum, P = 0.41). Statistically significant changes were found for coma (P = 0.004) and higher-order aberrations (P < 0.001), showing MICS significantly less changes in cornea.

CONCLUSIONS

Both MICS and mini-incision phacoemulsification do not degrade the optical quality of the cornea. Both surgeries do not induce a modification of the corneal astigmatism, even in the axis. It seems that 2 mm is the limit around which no optical changes are induced by cataract surgery in the human cornea.