Post Lasik Ectasia - Is It Always Predictable?!

To evaluate risks and predictability of postoperative ectasia after laser in situ keratomileusis (LASIK); discussing the incidences of this particular complication.

Seven eyes of four patients developed post-LASIK ectasia. All of themhad been treated for myopia and myopic astigmatism. All the cases of ectasia had a flap created using mechanical microkeratome (flap thickness 140 or 120 µm) and refractive error corrected using excimer lasers from B&L.

A retrospective analysesfollowing LASIK was made to reveal the pitfalls of this serious complication of corneal refractive surgery. The follow-up was between 2 and 10 years. After identifyingectasia, the retrospective analyses of topography maps was done to reveal any predisposing common factors for developingectasia.

Most prevalent risk factors are: PreOp topography patterns (asymmetric bowtie, inferior steepening, other abnormal maps). Ablation depth (as corneal strength is significantly greater in anterior 40% than in posterior 60% of stroma), residual bed thickness. Young age, thin cornea (low thickness, degree of Myopia and residual stromal bed are inter-related. PostOp Risk Factors are: Role of pregnancy: incidental, circumstantial or causal. Relaxing hormone increases during pregnancy that may contribute to changes in the physiochemical properties of corneal collagen leading to ectasia.Adenoviral inflammation leading to collagen loss due to apoptosis of stromal keratocytes& weakening of the stroma.Rubbing of the eye (?!)Increased IOP (?!)

These cases highlight the need for a high index of suspicion when making decision about vision correction, despite seemingly safe estimates of residual stromal bed thickness.Regular follow ups are mandatory in every case.In suspicious cases CCL should be scheduled.Timely performed CCL is very good option to halt ectasia