Ectasia After Corneal Refractive Surgery: A Systematic Review

Area of Science:

• Ophthalmology
• Corneal Surgery
• Refractive Surgery Outcomes

Background:

• Ectasia following refractive surgery is a significant concern.
• The precise incidence rates across different procedures remain unclear.
• Understanding these rates is crucial for patient safety and surgical planning.

Purpose of the Study:

• To determine the worldwide incidence of ectasia after photorefractive keratectomy (PRK), laser-assisted in situ keratomileusis (LASIK), and small incision lenticule extraction (SMILE).
• To compare the ectasia rates among these three common refractive surgical techniques.

Main Methods:

• A systematic review adhering to modified PRISMA guidelines.
• Searched eight electronic databases (1984-2021) for relevant publications.
• Calculated ectasia incidence based on reported cases and estimated annual surgery volumes.

Main Results:

• Identified 57 eyes with post-PRK ectasia, 1453 with post-LASIK ectasia, and 11 with post-SMILE ectasia (excluding those with risk factors).
• Incidences per 100,000 eyes were: PRK (20), LASIK (90), and SMILE (11).
• LASIK showed a 4.5 times higher rate of ectasia compared to PRK.

Conclusions:

• Post-refractive ectasia rates are lower for PRK compared to LASIK.
• SMILE demonstrates the lowest reported ectasia rate, but emerging cases warrant attention.
• Pre-existing keratoconus may be a more significant factor in postoperative ectasia than previously recognized.