Efficacy and safety of single-step transepithelial photorefractive keratectomy with the all-surface laser ablation SCHWIND platform without mitomycin-C for high myopia: A retrospective study of 69 eyes.

BACKGROUND: Studies suggest that transepithelial photorefractive keratectomy (TransPRK) with the all-surface laser ablation (ASLA)-SCHWIND platform is effective and safe for both low-moderate myopia and high myopia. In most studies, mitomycin-C is administered immediately after surgery to prevent corneal opacification (haze), which is a significant complication of photorefractive keratectomy in general. However, there is evidence that adjuvant mitomycin-C induces endothelial cytotoxicity. Moreover, a recent study showed that omitting adjuvant mitomycin-C did not increase haze in low-moderate myopia. The present case-series study examined the efficacy, safety, and haze rates of eyes with high myopia that underwent ASLA-SCHWIND TransPRK without adjuvant mitomycin-C. METHODS: All consecutive eyes with high myopia (≤-6 D) that were treated in 2018-2020 with the SCHWIND Amaris 500E® TransPRK excimer laser without adjuvant mitomycin-C in a tertiary-care hospital (France) and were followed up for 6 months were identified. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and spherical equivalent (SE) were recorded before and after surgery. Postoperative haze was graded using the 4-grade Fantes scale. Efficacy rate (frequency of eyes with 6-month UCVA ≤0.1 logMAR), safety rate (frequency of eyes that lost <2 BSCVA lines), predictability (frequency of eyes with 6-month SE equal to target SE±0.5 D), efficacy index (mean UCVA at 6 months/preoperative BSCVA), and safety index (BSCVA at 6 months/preoperative BSCVA) were computed. RESULTS: Sixty-nine eyes (38 patients) were included. Mean preoperative and 6-month SE were -7.44 and -0.05 D, respectively. Mean 6-month UCVA and BSCVA were 0.00 and -0.02 logMAR, respectively. Efficacy rate and index were 95.7% and 1.08, respectively. Safety rate and index were 95.7% and 1.13, respectively. Predictability was 85.5%. Grade 3-4 haze never arose. At 6 months, the haze rate was zero. CONCLUSIONS: ASLA-SCHWIND TransPRK without mitomycin-C appears to be safe as well as effective and accurate for high myopia.

Secondary Corneal Myxoma After DMEK (Descemet Membrane Endothelial Keratoplasty).

BACKGROUND This is a clinical case of secondary corneal myxoma, which developed 18 months after Descemet membrane endothelial keratoplasty (DMEK). The DMEK was performed to treat viral endotheliitis and, postoperatively, a diagnosis of Crohn's disease was made. CASE REPORT A 52-year-old male, with no prior clinical history, presented with an endotheliitis in the left eye. The hypothesis of an undetected herpes infection was favored, and an antiviral treatment was prescribed using valacyclovir (1 g orally, 3 times daily). After 3 months of antiviral treatment, the endotheliitis was successfully controlled and a combined intervention of DMEK endothelial graft and phacoemulsification was performed. A corneal tumor was found 18 months after a successful DMEK procedure and was surgically removed. A pathological examination revealed a secondary corneal myxoma. CONCLUSIONS Corneal myxomas are rare lesions, often secondary to trauma in the Bowman's membrane, which is why it is often called a myxomatous corneal degeneration. In this instance, there is no link with Carney complex. However, myxomas under the eyelid or within the orbit are often associated with cardiac myxomas. Treatment is strictly surgical, either by simple excision or by surgical excision followed by graft. To the best of our knowledge, this is the first time that such an association between DMEK and secondary corneal myxoma has been described in the literature.

Does Preoperative or Postoperative Graft Thickness Influence Postoperative Visual Acuity in Descemet Stripping Automated Endothelial Keratoplasty for Advanced Pseudophakic Bullous Keratopathy?

PURPOSE: To describe the evolution of best spectacle-corrected visual acuity (BSCVA) after Descemet stripping automated endothelial keratoplasty (DSAEK) for very advanced pseudophakic bullous keratopathy (PBK) and to determine whether the thickness of corneal grafts in DSAEK surgery for advanced PBK correlates with BSCVA 6 months postoperatively. METHODS: In a prospective, single-center, observational study, 141 eyes treated with DSAEK surgery were studied, from patients requiring posterior lamellar transplantation for advanced PBK. Graft thickness was measured during the surgery and in vivo 6 months later. The primary end point was BSCVA in LogMAR at 6 months. RESULTS: BSCVA 6 months after surgery was slightly correlated with 6 months graft thickness (r = 0.24, P = 0.01), but not with preoperative graft thickness (r = 0.01, P = 0.93). After adjusting for preoperative BSCVA, a better 6 months BSCVA was best associated with thinner grafts at 6 months (P < 0.01), but not with preoperative graft thickness (P = 0.80). CONCLUSIONS: BSCVA after DSAEK was significantly related to graft thickness measured 6 months after surgery, suggesting that better BSCVA after DSAEK is related to a decrease in graft thickness after surgery and not to the use of a thinner graft during surgery. This decrease may be because of the good health of the endothelium, but this result may be biased because of the intrastromal scars inherent in severe PBK. This study shows that DSAEK is a good option for advanced PBK but has low visual acuity potential recovery because of stromal scarring. Therefore, a penetrating keratoplasty may be indicated to obtain maximal recovery of visual acuity or for monocular patients.

Mechanical Modeling of a Keratoconic Cornea.

PURPOSE: We created a laboratory model of a cornea that was subjected to various pressures and thermal and mechanical factors to better understand the genesis of keratoconus deformation. METHODS: A steel base allowed for fixation of circular multilaminated patches of araldite (10 cm in diameter, 5 mm thick) in which the corneal anatomy was modeled. The model was plunged into a steam room (374°F/3 bars of pressure for 1 h) to ensure thermal homogeneity and was subjected to pressure using compressed air. Three models were assessed: a fault-free model with no lesion (model 1), and 2 models with a defect. The first of the defective models (model 2) had an external crack-type lesion (1 cm long; 1 mm deep). The second defective model (model 3) had one quarter thinned down using abrasive sandpaper (thickness reduced by 30%-40%). RESULTS: For model 1, which represented a healthy cornea, homogeneous modification was noted when examined under polarized light. In model 2, no excessive deformation was noticed, but there were stress lines at the edge of the lesion. Model 3 had a deformity, similar to keratoconic deformation. CONCLUSIONS: Our findings suggest that the disease progresses under environmental stresses, but only when there is an initial defect, and especially when there is a thinning down defect. This thinning down defect may be induced by continual eye rubbing.