Twelve-Month Outcomes of the Wavefront-Optimized Photorefractive Keratectomy for High Myopic Correction Compared with Low-to-Moderate Myopia

Abstract

Purpose: To evaluate the 12-months outcomes of photorefractive keratectomy (PRK) in patients with high myopia (≥ 6.0 diopters, D) compared with low-to-moderate myopia (< 6.0 D). Patients and Methods: Records of 46 patients (69 eyes) who underwent PRK for myopic and astigmatic correction between October 2015 and December 2018 were reviewed. High myopic eyes (29 eyes) were compared with low-to-moderate myopic eyes (40 eyes). All surgeries were adjunct with 0.02% mitomycin C intraoperatively. Measured outcomes included postoperative uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent, corneal haze rate, and any complications. Results: At 12 months post-PRK, 26 eyes (89.7%) in the high myopia and 39 eyes (97.5%) in the low-to-moderate myopia group had UDVA ≥ 20/20, (p=0.30). Average postoperative logMAR UDVA at 12 months was −0.04 (20/18) and −0.11 (20/15) for the high myopia and low-to-moderate myopia groups, respectively. No eyes in either group had residual refractive errors >1 D. No eyes in both groups developed significant corneal haze at month 12. No eyes had a loss of greater than two Snellen lines of CDVA at 12 months post-surgery. The efficacy and safety indices at 12 months post-surgery were not significantly different between groups (1.06±0.26 vs.1.14±0.27, p =0.25 and 1.14±0.27 vs 1.17±0.26, p=0.60 for low-to-moderate myopia vs high myopia groups, respectively). Conclusion: PRK with high myopic correction provides excellent refractive outcomes and is safe, compared to those of low-to-moderate myopic correction.

Management of Corneal Haze After Photorefractive Keratectomy

“…3 ), and corneal densitometry using Scheimpflug technology. Almost all patients develop some level of mild corneal opacification after PRK, but this is a normal response to stromal damage by corneal fibroblasts [ 96 , 97 ]. This haze is clinically insignificant and resolves naturally within 6–12 months, and it differs from the post PRK corneal haze that develops from stromal fibrosis, which is an abnormal healing response [ 96 ].…”

“…Almost all patients develop some level of mild corneal opacification after PRK, but this is a normal response to stromal damage by corneal fibroblasts [ 96 , 97 ]. This haze is clinically insignificant and resolves naturally within 6–12 months, and it differs from the post PRK corneal haze that develops from stromal fibrosis, which is an abnormal healing response [ 96 ]. Significant haze will be defined by the following: (1) patient has subjective visual disturbance; (2) findings are visually significant; (3) patient has loss of visual acuity on refraction; (4) signs of haze on biomicroscopy; and (5) haze is assessed at grade 2 or higher, as described by Fantes et al [ 98 ].…”

“…Early-onset post PRK haze develops within the first 3 months of surgery and potentially responds better to topical steroids [ 97 ]. Steroid resistance is common in the late-onset haze that develops up to 1 year after PRK [ 5 , 96 ]. For early-onset haze, we recommend an initial 12-week trial of intensive steroid therapy [ 5 , 99 ].…”

“…Afterwards, a sponge can be used to apply 0.02% MMC to the surface for 2 min [ 5 , 7 , 53 , 72 ], following which the cornea will be irrigated continuously with 20–30 cc of cold or room temperature saline solution. The application of MMC and the appropriate concentration are still controversial topics, especially for low myopia eyes [ 96 ], due to MMC-related tissue toxicity. However, studies performed to date show no evidence of epithelial cell and keratocyte toxicity [ 97 ].…”

Cirugía refractiva (CR) láser corneal, una comparación entre LASIK y PRK.

“…La miopía es el defecto refractivo más frecuente, provocando que los objetos lejanos se vean borrosos. Se puede clasificar en (20):…”