Wavefront-supported photorefractive keratectomy with the Bausch & Lomb Zyoptix in patients with myopic astigmatism and suspected keratoconus.
OBJECTIVE
To evaluate the safety, efficacy, and visual outcome of wavefront-supported photorefractive keratectomy (PRK) for the correction of myopia and myopic astigmatism in patients with suspected keratoconus.


METHODS
Forty eyes of 20 patients with myopia -4.0 to -8.0 diopters (D) (mean: -6.25 +/- 1.04 D), cylinder -1.0 to -2.50 D (mean: -1.61 +/- 0.71 D), and corneal thickness 440 to 488 microm were treated with wavefront-supported PRK. Corneal topography evaluation revealed a significantly irregular cylinder (inferior-superior difference > 1.5 D) with possible mild or forme fruste keratoconus. Aberrometry was performed with the Hartmann-Shack aberrometer, and corneal data were evaluated with the Orbscan system. Eyes were treated with the Technolas 217z Bausch & Lomb excimer laser and followed for a minimum of 40 months.


RESULTS
Following surgery, mean spherical equivalent refraction was +0.33 +/- 0.8 D. It was within +/- 0.5 D of the intended refraction in 95% of eyes and within +/- 1.0 D in 100% of eyes. Mean uncorrected visual acuity improved from 20/400 preoperatively to 20/25 postoperatively. Mean best spectacle-corrected visual acuity (BSCVA) remained unchanged (20/20) or improved to 20/20 in 92.5% of eyes and to 20/25 in 7.5% of eyes. Individually, BSCVA did not change in 28 (70%) eyes and increased by > or = 2 Snellen lines in 9 (22.5%) eyes; 3 (7.5%) eyes lost 1 Snellen line because of corneal haze. Laser treatment induced a significant flattening of the preoperative inferior corneal steepness in all eyes. Wavefront analysis demonstrated a significant decrease in high order aberrations (total root-mean-square and coma).


CONCLUSIONS
Wavefront-supported PRK appears to be effective for the treatment of myopia and astigmatism in patients with suspected keratoconus and thin, irregular corneas. Longer follow-up is needed to prove the safety of the procedure in this patient population.
Bahar
Irit
I
Department of Ophthalmology, Rabin Medical Center, Beilinson Campus, Petah Tiqwa, Israel. iritbahar@yahoo.com
Levinger
Shmuel
S
Kremer
Israel
I
D000328:Adult; D001251:Astigmatism / Q000150:complications / Q000473:pathology / Q000601:surgery*; D003315:Cornea / Q000473:pathology* / Q000601:surgery; D019781:Corneal Topography; D004867:Equipment Design; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000150:complications / Q000473:pathology / Q000601:surgery*; D054018:Lasers, Excimer; D008875:Middle Aged; D009216:Myopia / Q000150:complications / Q000473:pathology / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000379:methods*; D012029:Refraction, Ocular; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D014792:Visual Acuity