Astigmatism after a large scleral pocket incision in extracapsular cataract extraction

Surgically Induced Astigmatism after Manual Extracapsular Cataract Extraction or after Phacoemulsification Procedure

Astigmatic changes in three series of cataract surgical procedures were compared. The first two series comprised eyes having a manual extracapsular cataract extraction (ECCE) through a 12.0 mm or 8.0 mm incision and implant of a PMMA posterior chamber lens. The third series comprised eyes having phacoemulsification through a scleral pocket and implant of a PMMA posterior chamber lens. Preoperative keratometry measurements and corneal topography maps were compared with those obtained two days, one week, one, three and six months postoperatively. The keratometry measurements, obtained with computerized videokeratography, revealed: on day 2, 4.89 D (1st series), 3.95 D (2nd series), 2.66 D (3rd series); one week, respectively 4.46 D, 3.51 D and 2.14 D; one month, 0.65 D, 0.53 D and 0.05; three months, 1.44 D, 0.35 D and 0.36 D; six months, 1.36 D, 0.42 D and 0.48 D. The surgically-induced cylinder at three months was four times greater in the manual ECCE 12.0 mm incision series than in the phacoemulsification series. However, by six months all differences were markedly reduced. The results add to the growing evidence that the phacoemulsification procedure produces less astigmatism and more rapid visual rehabilitation than the manual ECCE procedure. Topographic analysis showed much less corneal steepening after phacoemulsification than after manual ECCE. However, all three surgical procedures offered satisfactory clinical results.