Clinical Outcomes of Aberration-Free All Surface Laser Ablation (ASLA) vs. Aberration-Free ASLA Assisted by Smart Pulse Technology in High Myopia: A One-Year Follow-Up Study

Purpose. To compare the clinical outcomes of aberration-free all surface laser ablation (ASLA) with and without the use of smart pulse technology (SPT) in high myopia. Methods. This study retrospectively analyzed 138 eyes (138 patients, only the right eye was selected) treated for high myopia (spherical equivalent ≥−6.00 diopters) using aberration-free ASLA (non-SPT group; 85 eyes) and aberration-free ASLA assisted by SPT (SPT group; 53 eyes). Examinations such as visual acuity, refraction, and haze were performed before the 12-month follow-up. Corneal epithelial healing time was assessed in the first postoperative day. Visual acuity and refraction examination were performed at 7 days and 1, 3, 6, and 12 months postoperatively. Corneal haze was evaluated in 1, 3, 6, and 12 months. Safety, efficacy, and corneal wavefront aberrations were assessed 12 months after the treatment. Results. At 12 months postoperatively, 60% versus 40% of eyes achieved 20/16 Snellen lines or better, and 92% versus 82% of eyes achieved 20/20 Snellen lines or better visual acuity in the SPT and the non-SPT groups, respectively. The average postoperative epithelial healing time was 3.75 ± 1.00 days in the SPT group and 3.73 ± 1.30 days in the non-SPT group ( P ≥ 0.05 ). The safety and the efficacy index of the SPT group were better than those of the non-SPT group in the follow-ups. The attempted spherical equivalent before the surgery and the achieved spherical equivalent at 12 months were comparable between the two groups. Regarding the aberrations, the results of Coma 90° in the SPT group were better than those in the non-SPT group ( P ≤ 0.05 ), but the increase of RMS HOAs (root mean square higher order aberrations), Coma 0°, and spherical aberration postoperatively had no statistical difference between the two groups ( P ≥ 0.05 ). Conclusions: Both aberration-free ASLA with and without SPT showed favorable safety, effectiveness, and predictability within 12 months for high myopia. And, ASLA using SPT might have potential advantages in the long-term visual quality.

Corneal collagen cross-linking epithelium-on vs. epithelium-off: a systematic review and meta-analysis

Background The purpose of the study was to determine the advantages and disadvantages of epi-on corneal cross-linking (CXL) techniques compared with standard epi-off CXL. Methods We searched MEDLINE and EMBASE for randomized controlled trials (RCTs) and non-randomized studies of interventions (NRSIs) and we evaluated the selected papers according to the Cochrane risk of bias tool. We considered, as primary outcomes, average Kmax flattening, changes in uncorrected and corrected distance visual acuity (UDVA and CDVA); as secondary outcomes, we considered changes in pachymetry values and endothelial cell density (ECD). We also investigated adverse events related to the treatments and treatment failure. Meta-analysis was conducted with a fixed or random-effects model using weighted mean difference (MD) with 95% confidence interval (CI) as the effect size. Results A total of 15 studies were included and among these 15 trials, 9 were RCTs and 6 were NRSIs, but only 4 studies showed no high risk of bias and were included in this meta-analysis. Our analysis revealed significant postoperative differences in CDVA (MD = 0.07; 95% CI 0.04 to 0.10; P < 0.001), and no significative differences in UDVA, Kmax, central corneal thickness (CCT) and ECD (P > 0.05). Epi-on CXL protocol was found to be significantly less prompt to have risks of delay in epithelial healing (P = 0.035) and persistent stromal haze (P = 0.026). Conclusion Epi-on CXL is as effective as epi-off CXL. Except for a higher significant improvement in CDVA with current epi-on protocols, our meta-analysis demonstrates that epi-on and epi-off CXL have comparable effects on visual, topographic, pachymetric, and endothelial parameters. Epi-on CXL has clinical advantages in terms of comfort and avoidance of complications as it reduces the risk of developing delay in epithelial healing and persistent stromal haze.

Effects of Selective Peroxisome Proliferator Activated Receptor Agonists on Corneal Epithelial Wound Healing

The effects of each subtype-selective peroxisome proliferator activated receptor (PPAR) agonist (α, β/δ, γ) on corneal epithelial wound healing were investigated using a rat corneal alkali burn model. After the alkali burn, each PPAR agonist or vehicle ophthalmic solution was instilled topically onto the rat’s cornea. Corneal epithelial healing processes were evaluated by fluorescein staining. Pathological analyses and real-time reverse transcription polymerase chain reactions were performed to evaluate Ki67 (proliferative maker) expression and inflammatory findings. The area of the corneal epithelial defect at 12 h and 24 h after the alkali burn was significantly smaller in each PPAR group than in the vehicle group. Ki67 mRNA expression was increased in the PPARβ/δ group, whereas mRNA expressions of inflammatory cytokines were suppressed in all of the PPAR agonist groups. Nuclear factor kappa B (NF-κB) was the most suppressed in the PPARγ group. The accelerated corneal epithelial healing effects of each PPAR ligand were thought to be related to the promotion of proliferative capacity and inhibition of inflammation.

Pharmacological HIF-1 stabilization promotes intestinal epithelial healing through regulation of α-integrin expression and function

Intestinal epithelia are critical for maintaining gastrointestinal homeostasis. Epithelial barrier injury, causing inflammation and vascular damage, results in inflammatory hypoxia and thus healing occurs in an oxygen-restricted environment. The transcription factor hypoxia inducible factor (HIF)-1 regulates genes important for cell survival and repair, including the cell adhesion protein β1-integrin. Integrins function as αβ-dimers and α-integrin-matrix binding is critical for cell migration. We hypothesized that HIF-1 stabilization accelerates epithelial migration through integrin-dependent pathways. We aimed to examine functional and post-translational activity of α-integrins during HIF-1-mediated intestinal epithelial healing. Wound healing was assessed in T84 monolayers over 24 hours with/without prolyl-hydroxylase inhibitor (PHDi) (GB-004), which stabilizes HIF-1. Gene and protein expression were measured by RT-PCR and immunoblot, α-integrin localization was assessed by immunofluorescence. α-integrin function was assessed by antibody-mediated blockade and integrin-α6 regulation was determined by HIF-1α chromatin immunoprecipitation. Models of mucosal wounding and TNBS-induced colitis were used to examine integrin expression and localization in vivo. PHDi-treatment accelerated wound closure and migration within 12 hours, associated with increased integrin-α2 and α6 protein, but not α3. Functional blockade of integrins-α2 and α6 inhibited PHDi-mediated accelerated wound closure. HIF-1 bound directly to the integrin-α6 promoter. PHDi treatment accelerated mucosal healing, which was associated with increased α6 immunohistochemical staining in wound-associated epithelium and wound-adjacent tissue. PHDi-treatment increased α6 protein levels in colonocytes of TNBS mice and induced α6 staining in regenerating crypts and re-epithelialized inflammatory lesions. Together these data demonstrate a role for HIF-1 in regulating both integrin-α2 and α6 responses during intestinal epithelial healing.