Densitometric assessment of corneal transparency after correction of moderate myopia by femtosecond extraction of the lenticule through a small incision and using laser keratomilesis in situ with femtosecond assistance

Relevance. The study of the mechanisms of insufficiently rapid achievement of high visual acuity in the early postoperative period in the correction of myopia by the SMILE method is relevant. Purpose. To evaluate changes in corneal densitometry parameters after SMILE and FS-LASIK surgery in patients with moderate myopia. Material and methods. A study of 152 patients with moderate myopia was conducted, 68 were operated by SMILE and 84 – FS-LASIK. All procedures were performed using a VisuMax femtosecond laser and a MEL 80 excimer laser (Carl Zeiss Meditec, Germany). Assessment of visual acuity, corneal structure (OCT, Optovue, USA), corneal densitometry (Pentacam Scheimpflug, Germany) were performed before the operation, on the 1st, 5th day, 3, 6, 12 months after the operation. OCT scans were analyzed using the ImageJ program. Results. Оn the 1st day after SMILE, visual acuity (p=0.01) and transparency of the anterior and middle layers of the cornea were reduced than after FS-LASIK in the zone from 0 to 2 mm (p=0.045, p=0.001), from 2 to 6 mm (both p=0.001). These differences became statistically insignificant 5 days after surgery. By three and six months in the FS-ERASER group, the corneal transparency in the middle layers were reduced in the 0–2 mm and 2–6 mm zones (p=0.0001, p=0.001). In both groups, by 12 months, the corneal backscattering reached the values of the preoperative period (p>0,05). Conclusion. Refractive operations SMILE and FS-LASIK are accompanied by a decrease in corneal transparency, which is restored to preoperative values by 12 months. In the early postoperative period, an increase in densitometry indicators and a slower recovery of visual acuity after SMILE surgery may be due to active remodeling of the interface, which includes fragments of collagen fibrils and cellular components inside the intrastromal space. Key words: SMILE, FS-LASIK, densitometry, myopia

The effect of Cultured Autologous Oral Mucosal Epithelial Cell Sheet (CAOMECS) on the ocular surface reconstruction

IntroductionOral epithelial cells were recently shown to be able to differentiate into corneal epithelium and the efficacy of CAOMEC has been suggested by the presence of epithelium replacement. Therefore, the aim was to evaluate the treatment outcome in limbal stem cell deficiency (LSCD) by adding the CAOMEC to the regular amniotic membrane (AM) treatment.Material and methodsEyes with LSCD were randomized in two groups to undergo either CAOMECS combined with AM transplantation (A group) or AM transplantation alone (B group). Clinical outcome measures were corneal epithelium healing, best corrected visual acuity, symblepharon, corneal transparency, corneal neovascularization and ocular surface inflammation.ResultsThe normal corneal epithelialization rate in group A (73.33%) was higher than that in group B (35.48%), and the average healing time was shorter (3.45 ± 2.12 w vs.4.64 ± 1.63). The symblepharon in above two groups were improved in the first 3 m after surgery, however, after 6 m, part of the B group had recurrence. In improving corneal transparency, group A has obvious advantages. Corneal neovascularization (CNV) was improved to some extent in the first 3 m after surgery, but group A (1.47 ± 0.64) was better than group B (1.94 ± 0.85) after 6 m. Both groups can improve the inflammatory state to some extent.ConclusionsThe transplantation of CAOMECS offers a viable and safe alternative in the reconstruction of a stable ocular surface. The effect is better than that of traditional AM transplantation, mainly in promoting corneal epithelialization, improving ocular surface structure, reducing fiber and vascular infiltration.

Investigation of corneal topographic and densitometric properties of Wilson's disease patients with or without a Kayser-Fleischer ring

Background To investigate the topographic measurements and densitometry of corneas in Wilson’s disease (WD) patients with or without a Kayser-Fleischer ring (KF-r) compared to healthy individuals. Methods This cross-sectional study included 20 WD patients without a KF-r (group I), 18 WD patients with a KF-r (group II), and 20 age-matched controls (group III). The Pentacam high resolution imaging system is used to determine corneal topographic measurements and densitometry. Results Mean age for groups I, II and III was 25.40 ± 6.43 years (14–36 years), 25.38 ± 6.96 years (16–39 years), 23.60 ± 6.56 years (17–35 years), respectively (P = 0.623). There was no significant difference between the groups in terms of the anterior corneal densitometry values (P > 0.05), while the 6–10 mm and 10–12 mm mid stroma and the 2–6 mm, 6–10 mm, and 10–12 mm posterior corneal densitometry values in group II were significantly higher than those in groups I and III (for all values, P < 0.05). However, the 10–12 mm posterior corneal densitometry values in group I were also significantly higher than those in group III (P = 0.038). The central corneal thickness (CCT), thinnest corneal thickness (tCT), and corneal volume (CV) values in groups I and II were significantly lower than those in group III (for CCT values, P = 0.011 and P = 0.009; for tCT values, P = 0.010 and P = 0.005; for CV values, P = 0.043 and P = 0.029). Conclusion In WD patients with a KF-r, corneal transparency decreased in the peripheral posterior and mid stromal corneal layers; for these patients, corneal transparency may be impaired not only in the peripheral cornea but also in the paracentral cornea.

A new storage medium containing amphotericin B versus Optisol-GS for preservation of human donor corneas

Background/AimWe compared the quality of human donor corneas stored in a cold storage medium containing 2.5 μg/ml of amphotericin B (Kerasave, AL.CHI.MI.A. S.R.L., Ponte San Nicolò, Italy) and Optisol-GS (Bausch & Lomb Inc., Bridgewater, NJ, USA) for 14 days.MethodsSixteen pairs of human donor corneas were collected in Eusol-C (AL.CHI.MI.A. S.R.L., Ponte San Nicolò, Italy). Next, all tissues underwent the first evaluation that included the assessments of central corneal thickness (CCT), endothelial cell density (ECD) measured using both trypan blue staining and specular microscopy, endothelial cell (EC) mortality and morphology, and corneal transparency within 24 hours from recovery (Day 1). Afterwards, one cornea of each pair was transferred into Kerasave or Optisol-GS. ECD and CCT were also assessed at Day 7, and all the metrics were evaluated again at the end of the storage period (Day 14).ResultsAt all tested time points, no differences were found in the qualitative (corneal transparency, EC morphology) and quantitative metrics (ECD, CCT, EC mortality) between the Kerasave and the Optisol-GS storage groups. At Day 14, the corneas stored in Kerasave and Optisol-GS showed ECD of 2312±98 and 2335±128 cells/mm2 (p=0.886), CCT of 717±17 and 697±19 μm (p=0.454) and central EC mortality of 0.54%±0.40% and 0.14%±0.14% (p=0.719), respectively.ConclusionsThe new amphotericin B−containing medium Kerasave was comparable to Optisol-GS in terms of preservation of corneal characteristics at 2–8°C for 14 days.