Early onset ectasia following laser in situ keratomileusus: case report and literature review.

PURPOSE: Laser in situ keratomileusis (LASIK) has been associated with the development of postoperative corneal ectasia. We present a case of early onset ectasia after LASIK, review known risk factors in development, and discuss possible strategies for prevention.
METHODS: A 39-year-old man underwent bilateral LASIK for moderate myopia. Preoperative cycloplegic refractions were -9.00 + 0.25 x 140 degrees OD and -7.75 sphere OS. Corneal topography demonstrated mild inferior steepening bilaterally although definite evidence of keratoconus by either the Klyce/Maeda and Smolek/Klyce keratoconus screening tests was not present. Following the creation of flaps with 160-microm plates, ablations of 93 microm OD and 80 microm OS were performed, estimated to leave residual stromal beds of at least 314 microm OD and 330 microm OS.
RESULTS: On the first postoperative day, uncorrected visual acuities were 20/400 OD and 20/40 OS. On the fifth postoperative day, the patient's uncorrected visual acuity was 20/400 OD, and 20/300 OS. Corneal topography of the right eye showed profound inferior steepening with an apical corneal power in excess of 57 D; topography of the left eye showed mild inferior steepening. Eighteen months after surgery best corrected visual acuity was 20/40 OD and 20/30 OS with rigid gas permeable contact lenses.
CONCLUSIONS: This case highlights the need for a high index of suspicion when one notes an asymmetric bow-tie pattern on preoperative LASIK corneal topography, despite seemingly safe estimates of residual stromal bed thickness.