What Is the Failure Rate of LASIK Flaps Healing Properly?

Overall Failure and Complication Rates

Modern 2026 surgical data indicates that the overall rate of "flap failure" is remarkably low, occurring in less than 0.5 percent of primary LASIK procedures. When complications do occur, they are typically divided into mechanical issues (displacement), inflammatory issues (DLK), or cellular issues (ingrowth). Because of the transition to femtosecond lasers for flap creation, the "catastrophic" flap failures of the early 2000s, such as free caps or incomplete passes, have been virtually eliminated from modern practice.

Corneal Striae: Wrinkles in the Flap

Striae are microscopic folds or "wrinkles" in the corneal flap that can occur if the flap is slightly misaligned during repositioning or if it shifts during the first few hours of healing.

Macro-striae - Large folds that usually occur due to accidental eye rubbing or trauma. These affect vision significantly and have an incidence rate of roughly 0.1 percent.

Micro-striae - Tiny wrinkles that often do not affect visual acuity. These are found in about 1 percent to 2 percent of cases upon close microscopic inspection but rarely require treatment. In 2026, if macro-striae are detected, the surgeon will "lift and smooth" the flap within the first 24 hours, which has a 98 percent success rate in restoring perfect clarity.

Epithelial Ingrowth: Cells in the Wrong Place

Epithelial ingrowth occurs when the surface cells of the cornea begin to grow underneath the LASIK flap. This typically happens if there was a slight defect at the flap edge during surgery. Data from 2026 shows that ingrowth occurs in approximately 0.1 percent to 1 percent of primary LASIK cases. However, the risk is significantly higher (up to 10 percent) during "enhancement" surgeries where an old flap is lifted. Most cases of ingrowth are self-limiting and stay at the very edge of the flap, but if the cells migrate toward the center of vision, the flap must be lifted and "scraped" clean to prevent blurring and irregular astigmatism.

Diffuse Lamellar Keratitis (DLK): "Sands of Sahara"

DLK is a rare, sterile inflammatory response that occurs in the space between the flap and the corneal bed. It is characterized by a fine, white granular infiltrate that looks like shifting sand under a microscope. In 2026, the incidence of significant DLK is roughly 0.1 percent. It is typically caused by a reaction to surgical debris, bacterial toxins, or even the laser energy itself. When caught early during the Day 1 post-op visit, DLK is highly responsive to intensive steroid drops, with a 99 percent resolution rate without any permanent loss of vision.