[Complications of refractive excimer laser surgery]

In surface ablation, haze is the most frequent complication. After LASIK, microkeratome-related complications are rare today and usually resolve without sequelae, provided no ablation was done. Postoperative flap complications such as flap slippage usually occur during the first few days after surgery and should be treated as early whenever present. Interface complications are a new diagnostic entity as the interface between flap and stroma presents a space where fluid or cells can accumulate. Diffuse lamellar keratitis usually occurs within the first few postoperative days and should be treated aggressively to avoid scarring. Epithelial ingrowth is another rare complication usually requiring treatment. Corneal hydrops with fluid accumulation in the interface is a very rare but important phenomenon related to steroid-induced glaucoma but presenting with false low tonometry readings. Corneal ectasia is extremely rare and in most cases related to thin stromal beds. However, its pathogenesis is not yet completely understood, and it may occur in "normal" eyes, too. Dry eye syndrome is the most frequent complication after LASIK. It is usually benign but may cause significant visual impairment in rare cases.