A case report of central toxic keratopathy in a patient post TransPRK (followed by corneal collagen cross-linking).

PURPOSE: The purpose of this article is to report a case of central toxic keratopathy in a patient post transepithelial photorefractive keratectomy (TransPRK), followed immediately by corneal collagen cross-linking. METHODS: This article describes the case of a 26-year-old male after bilateral aberration-free, TransPRK laser (Schwind Amaris 750S). The procedure was performed for compound myopic astigmatism in November 2015, followed immediately by accelerated corneal collagen cross-linking for early keratoconus. RESULTS: From day 3 post-op, tear film debris underneath both contact lenses with corneal haze and early, progressive central anterior stromal opacity formation only in the left eye were noted. At 2 weeks post-op, the left eye was noted to have a significant hyperopic shift with central corneal thinning in the anterior stroma. A central anterior stromal dense opacity had formed in the left eye with the surrounding superficial stromal haze. As of month 2, the opacity gradually started to improve in size and density. The hyperopic shift peaked at 2 months and continued to improve, largely due to epithelial compensation with a gradual recovery of stromal thickness. CONCLUSION: The question remains as to what provokes the typical central corneal necrosis/thinning in central toxic keratopathy. We hypothesize that the space between the contact lens and the corneal surface post TransPRK is prone to a "pseudo-interface pathology" that could mimic diffuse lamellar keratitis-like pathology. Suboptimal lid hygiene, resulting in tear film combinations of bacteria, inflammatory cells, matrix metalloproteinases and other proteolytic enzymes, contributes to the degradation of vulnerable, exposed collagen stromal tissue post TransPRK or any surface corneal ablation. Refractive surgeons should maintain a healthy lid margin and tear film, especially in contact lens wearers, to prevent potential complications in refractive surgery procedures.

A pharmacological modification of pain and epithelial healing in contemporary transepithelial all-surface laser ablation (ASLA).

PURPOSE: We report our experience with the use of the matrix regenerating agent (RGTA) Cacicol(®) after reverse transepithelial all-surface laser ablation (ASLA)-SCHWIND to assess the safety, efficacy, pain, and epithelial healing. METHODS: Forty eyes of 20 myopic patients were prospectively recruited to a randomized fellow eye study. Patients underwent transepithelial ASLA in both eyes, with one of the eyes randomly assigned to the use of the RGTA Cacicol. Postoperative pain and vision were subjectively assessed with the use of a questionnaire on the operative day, at 24 hours, 48 hours and 72 hours. Epithelial defect area size was measured at 24 hours, 48 hours, and 72 hours. Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were assessed at 1 month. RESULTS: Mean UDVA at 1 month was LogMAR 0.028. The epithelial defect area was 10.91 mm(2) and 13.28 mm(2) at 24 hours and 1.39 mm(2) and 1.24 mm(2) at 48 hours for treated and nontreated eyes, respectively. Overall, 50% and 65% of treated and nontreated eyes healed by 48 hours. There was no statistically significant difference in the subjective vision between the groups, although vision of patients in the RGTA group was reported to be better. Pain scores were better at 24 hours and 48 hours in the RGTA group but with no statistically significant difference. CONCLUSION: The use of RGTA Cacicol shows faster epithelial recovery after transepithelial ASLA for myopia. Subjectively reported scores of pain and subjective vision were better in the RGTA group, although the difference was not statistically significant. There seems to be a consensual acceleration of epithelial healing even in eyes that did not receive treatment. There were no adverse events and no incidents of inflammation, delayed healing, or haze.

Single-step transepithelial ASLA (SCHWIND) with mitomycin-C for the correction of high myopia: long term follow-up.

PURPOSE: We wanted to compare the outcomes of single-step modified transepithelial photorefractive keratectomy (tPRK) termed a SCHWIND all surface laser ablation (ASLA) versus conventional alcohol-assisted photorefractive keratectomy (PRK) and laser-assisted in situ keratomileusis (LASIK) for the correction of higher myopia of 6.00 diopters (D) or more, in an area with high risk of haze due to high intensity of sunlight. METHODS: We used a prospective interventional cohort with matched retrospective control groups. Patients with >6 D myopia and <3.5 D of astigmatism were included. All treatments were performed with the SCHWIND Amaris system using aspheric ablation profiles. Mitomycin C was used in all PRK and ASLA cases. Outcomes were postoperative refraction, visual acuity, stability, and complications. The follow-up period was up to 12 months. RESULTS: In total, 101 eyes were included after exclusions. Mean preoperative spherical equivalent refraction was -7.9 D, -8.2 D, and -7.4 D in the ASLA (n=41), PRK (n=29), and LASIK (n=31) groups. Mean postoperative spherical equivalent at 12 months postoperatively was -0.1 (standard deviation [SD]: 0.34), -0.2 (SD: 0.59), and -0.08 (SD: 0.36) in the ASLA, PRK, and LASIK groups, with 91.4%, 85.7%, and 83.9% within 0.5 D of target, respectively. Refractive outcomes and regression at 12 months did not vary among groups (P>0.05). Mean logMAR (logarithm of the minimum angle of resolution) uncorrected distance visual acuity at 12 months was 0.00 (SD: 0.05), 0.06 (SD: 0.1), and 0.05 (SD: 0.09) in the ASLA, PRK, and LASIK groups, with significantly better vision in the tPRK group versus LASIK (P=0.01) and PRK (P=0.01) groups. CONCLUSION: ASLA (SCHWIND) tPRK with mitomycin C for high myopia demonstrates comparable refractive outcomes to LASIK and PRK, with relatively favorable visual acuity outcomes. There was no increased incidence of haze in the ASLA group.

Transepithelial photorefractive keratectomy with crosslinking for keratoconus.

PURPOSE: To analyse visual, refractive and topographic outcomes of combining transepithelial photorefractive keratectomy (tPRK) with simultaneous corneal crosslinking for the visual rehabilitation of contact lens intolerant keratoconus patients. METHODS: Patients with topographically significant keratoconus, limited corrected vision and intolerant of contact lenses were prospectively recruited, subject to ethical approval and consent. All patients underwent single step aspheric tPRK and sequential crosslinking. Preoperative vision, refraction, corneal topography and wavefront were assessed, with postoperative assessment at 1, 3, 6, and 12 months. RESULTS: 22 eyes of 14 patients were included in the pilot study. Mean age was 32 years (SD 6.8, range 24 to 43). Mean preoperative unaided vision was 1.39 LogMAR (SD 0.5) best corrected 0.31 LogMAR (SD 0.2). Mean preoperative spherical equivalent was -2.74 Diopters (D) (SD 4.1 range -12.25 to +7.75), and mean cylinder -2.9 D (SD 1.2, range 0 to -5.5). Mean central corneal thickness was 461um (SD 29, range 411 to 516). Vision improved postoperatively; unaided 0.32 LogMAR (SD 0.4), best corrected 0.11 (SD 0.13) (P=<0.005). Mean postoperative cylinder was -1.4D (SD1.2), significantly reduced (p<0.005). Maximum keratometry (Kmax) was stable throughout postoperative follow up. (p<0.05). CONCLUSIONS: Non topographic transepithelial PRK with simultaneous crosslinking improves vision, and may offer an alternative to keratoplasty in contact lens intolerant keratoconus. Further comparative studies to topographic PRK techniques are indicated.