[Haze and regression after photoreactive keratectomy (PRK)]

Area of Science:

• Ophthalmology
• Refractive Surgery
• Corneal Surgery

Background:

• Photorefractive keratectomy (PRK) is a standard surgical option for correcting myopia.
• The German Ophthalmological Society (DOG) acknowledges PRK for myopia between -1.0 and -6.0 diopters.
• Increased risks associated with PRK for myopia exceeding -6.0 diopters necessitate further investigation.

Purpose of the Study:

• To evaluate the outcomes of PRK in myopic patients, particularly those with high myopia.
• To assess the incidence and impact of postoperative haze after PRK.
• To compare the safety and efficacy of PRK for different levels of myopia.

Main Methods:

• A cohort of 212 myopic patients (338 eyes) underwent PRK between June 1994 and October 1997.
• Preoperative myopia ranged from -1.25 to -11.25 diopters.
• Standard PRK procedure involved mechanical abrasion, excimer laser treatment, and a specific post-operative medication regimen including corticosteroids for 5 months.

Main Results:

• Seventeen eyes (4.9%) developed persistent haze (grade 1-2 or higher) 12 months postoperatively.
• These 17 eyes experienced an average regression of -1.67 diopters and lost at least two lines of best-corrected visual acuity.
• All 17 eyes with persistent haze had preoperative myopia greater than -6.0 diopters.

Conclusions:

• Postoperative haze after PRK is typically transient, but persistent haze correlates with refractive regression and visual acuity loss.
• PRK in eyes with preoperative myopia exceeding -6.0 diopters is associated with a higher risk of persistent haze.
• Patients with high myopia considering PRK should be informed of these risks, and Laser-assisted in situ keratomileusis (LASIK) should be considered as an alternative.