EXCIMER-LASER SUPERFICIAL KERATECTOMY FOR PROUD NEBULAE IN KERATOCONUS

Contact lens intolerance in keratoconus may be due to the formation of a proud nebula at or near the apex of the cone. Excimer laser superfi cial keratectomy was performed as an outpatient procedure in 10 eyes o f 10 keratoconic patients with proud nebulae as treatment for their co ntact lens intolerance. The mean period of contact lens wear before th e development of intolerance was 13.4 years (range 2 to 27 years). Fol lowing the development of intolerance, three patients abandoned contac t lens wear in the affected eye while the remainder experienced a redu ction in comfortable wearing time (mean=3.75 hours; range: 0-14 hours) . Ah patients had good potential Snellen visual acuity with a contact lens of 6/9 (nine eyes) and 6/12 (one eye). The proud nebulae were dir ectly ablated with a 193 nm ArF excimer laser using a 1 mm diameter Be tween 100-150 pulses were sufficient to ablate the raised area. Patien ts experienced no pain during the procedure and reported minimal disco mfort postoperatively. In all cases flattening of the proud nebulae wa s achieved. Seven patients were able to resume regular contact lens we ar (mean wearing time =10.17 hours; range 8 to 16 hours). In three pat ients, resumption of contact lens wear was unsuccessful because of con e steepness. All patients achieved postoperative Snellen visual acuity of 6/12 or better with a contact lens. Four patients experienced a lo ss of one line in Snellen acuity. The mean follow up period was 8.3 mo nths (range 2 to 17 months). Excimer laser superficial keratectomy is a useful technique for the treatment of contact lens intolerance cause d by proud nebulae in patients with keratoconus. Penetrating keratapla sty is thus avoided.