Purpose To measure central flap thickness in eyes with ectasia after LASIK and to compare these values with estimated anticipated flap thickness based on average published values for each device used for flap creation. Setting Emory Vision at Emory University, Atlanta GA, USA Methods Confocal microscopic analysis using the Confoscan 3 (Nidek technologies) to measure central flap thickness in eyes with ectasia after LASIK, and evaluation of pre-LASIK records, including basic patient demographics, preoperative corneal topographies, estimated anticipated flap thickness based on published average thickness values, and residual stromal bed thickness (RSB) calculations using both measured and estimated flap thicknesses. Results Fifty eyes from 29 patients were evaluated. Average measured flap thickness was (138 ± 26 μ, range 90 to 220 μ). There were no significant differences between measured and estimated flap thicknesses (138 vs. 135 μ, p = 0.5) or RSB (329 vs. 332 μ, p = 0.7), nor were there any differences in flap thickness between eyes with normal or abnormal corneal topographies. Only one eye had a measured flap resulting in unintended RSB < 250 microns; this occurred in an eye with abnormal topography. Conclusions Measured central flap thickness was not thicker than estimated for the vast majority of eyes developing ectasia after LASIK. Thus, excessively thick flaps do not appear to be a major contributing factor to the pathogenesis of ectasia after LASIK.

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A 39-year-old woman developed corneal ectasia after laser in situ keratomileusis. Intracorneal ring segments (Intacs, Addition Technology, Inc.) were placed in the left eye in November 2004. Postoperatively, inferior topographic steepening decreased significantly and a rigid gas-permeable lens yielded 20/25 visual acuity. However, the patient reported persistent discomfort that did not improve with topical medications or a bandage contact lens. In May 2005, confocal microscopy demonstrated a corneal nerve in direct contact with the inferior segment. Both segments were removed, and after removal, the patient reported complete resolution of the pain.

These cases are, to our knowledge, the first to report confocal microscopic findings in isolated polymorphic amyloid degeneration and combined polymorphic amyloid degeneration with posterior crocodile shagreen.

In this patient with Fleck corneal dystrophy, corneal clarity and BSCVA were maintained 6 years after bilateral myopic LASIK, suggesting that LASIK does not stimulate visually significant exacerbation of Fleck corneal dystrophy.