Descemetic Deep Anterior Lamellar Keratoplasty versus Penetrating Keratoplasty in Advanced Keratoconus: Comparison of Visual and Refractive Outcomes.

Purpose: To assess and contrast the visual and refractive results of Descemetic deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) in the treatment of advanced keratoconus. Design: Retrospective, comparative, interventional study. Methods: This study enrolled eyes affected by keratoconus with preoperative mean keratometry ≥60 diopters (D) that were treated with either Descemetic DALK (30 eyes) or PK (29 eyes) by using always the same corneal diameters (8.00mm recipient; 8.25mm donor cornea) and the same suture technique (10-0 nylon double-running 12-bites continuous suture). The outcome measures were postoperative uncorrected distance visual acuity (UDVA), best-corrected distance visual acuity (CDVA), subjective refractive astigmatism (SRAst), and keratometric astigmatism at 3mm area (SimK), spherical equivalent (SEq). Results: Postoperative visual acuity significantly improved in both groups. Mean CDVA was higher in the DALK group 3 months (DALK 0.61, PK 0.42, p<0.05), 6 months (DALK 0.69, PK 0.44, p<0.05), and 12 months (DALK 0.72, PK 0.45, p<0.05) postoperatively. However, 6 months after suture removal, CDVA was not statistically different between the two groups (DALK 0.71, PK 0.75, p>0.05). Final SRAst and SimK also were comparable between the two groups (respectively DALK 2.97, PK:2.81, p>0.05; DALK 3.91, PK 2.37, p>0.05). No significant statistical differences were noted for UCVA and SEq data during the entire follow-up period between the two groups. Conclusion: Both methods of corneal transplantation resulted in a notable enhancement of visual and refractive outcomes in eyes afflicted by advanced keratoconus. Descemetic DALK demonstrated superior visual acuity before suture removal, whereas DALK and PK exhibited comparable results in terms of visual acuity, refractive correction, and keratometric astigmatism after suture removal.

Topography-Guided Transepithelial Photorefractive Keratectomy for the Treatment of Persistent and Visually-Significant Adenoviral Corneal Infiltrates.

Purpose: To evaluate visual and refractive outcomes of customized photorefractive keratectomy (PRK) in subjects with persistent subepithelial corneal opacities secondary to adenoviral epidemic keratoconjunctivitis (EKC). Patients and Methods: Prospective study, which recruited patients with persistent and visually-significant post-EKC corneal opacities unresponsive to prolonged topical therapy (6 months or more). Outcome measures: uncorrected and best-corrected distance visual acuity, subjective refractive astigmatism, keratometric astigmatism, spherical equivalent, minimum corneal thickness, and corneal morphological irregularity index. Subjects were followed for 12 months post-treatment. Results: Eighteen eyes of 18 patients aged between 32 and 75 years treated with topography-guided transepithelial PRK with iRes excimer laser (iVIS Technologies, Taranto, Italy) from June 2020 to July 2021. After 12 months, the mean UDVA improved from 1.0±0.00LogMAR pre-op to 0.15±0.154LogMAR, and the mean CDVA improved from 0.4±0.41LogMAR pre-op to 0.0±0.00LogMAR. With respect to UDVA, all treated eyes (100%) showed an improvement of 6 ETDRS lines or more and with respect to CDVA, 9 out of 18 eyes (50%) showed an improvement of 6 ETDRS lines or more. The mean ablation depth was 54.7±5.9µm. A statistically significant improvement was observed in all topographic indices. No infiltrate recurrence, post-treatment corneal haze, ocular hypertension or other side effects were observed throughout the follow-up period. Conclusion: Topography-guided PRK could be considered an effective and safe treatment option to improve visual acuity in patients affected by persistent and visually-significant subepithelial corneal infiltrates caused by EKC.

Corneal stromal demarcation line after 4 protocols of corneal crosslinking in keratoconus determined with anterior segment optical coherence tomography.

PURPOSE: To use anterior segment optical coherence tomography (AS-OCT) to compare corneal stromal demarcation line depth after 4 treatment protocols of corneal crosslinking (CXL). SETTING: Eye Clinic, Sapienza University of Rome, Terracina (Latina), Italy. DESIGN: Prospective case series. METHODS: Patients with progressive keratoconus were delegated to one of the following CXL treatments: (1) conventional epithelium (epi)-off 3 mW/cm2 according to the standard Dresden protocol (C-CXL group), (2) accelerated epi-off 10 mW/cm2 (A-CXL group), (3) transepithelial epi-on 3 mW/cm2 (TE-CXL group), or (4) transepithelial epi-on by iontophoresis 10 mW/cm2 (I-CXL group). Two independent observers measured the corneal stromal demarcation line using AS-OCT. RESULTS: The study comprised 70 patients (120 eyes, 30 eyes in each group). The corneal stromal demarcation line was identified on AS-OCT scans in 109 eyes (90.8%). One month after the treatment, the mean stromal demarcation line depth was 275.05 µm ± 41.83 (SD) in the C-CXL group, 279.35 ± 33.07 µm in the A-CXL group, 132.60 ± 22.14 µm in the TE-CXL group, and 235.40 ± 37.08 µm in the I-CXL group. The difference in stromal demarcation line depth was not statistically significant between the C-CXL and A-CXL group, but it was statistically significant (P < .05) between the epi-off and epi-on CXL groups and between the 2 epi-on groups, where the demarcation line was significantly deeper in the I-CXL group than in the TE-CXL group. CONCLUSION: The corneal stromal demarcation line was significantly deeper after epi-off 30-minute standard CXL treatment and after epi-off 9-minute accelerated CXL with high-intensity ultraviolet-A irradiation.

Comparison of optical low coherence reflectometry and ultrasound pachymetry in the measurement of central corneal thickness before and after photorefractive keratectomy.

PURPOSE: To compare an ultrasound pachymeter with an optical low coherence reflectometry (OLCR) pachymeter for measuring pre- and postoperative central corneal thickness of patients undergoing photorefractive keratectomy (PRK). METHODS: In a prospective, noncomparative, interventional study, 48 myopic eyes (mean manifest refractive spherical equivalent: -4.93 +/- 2.93 diopters [D]) of 30 healthy patients underwent PRK. Pre- and postoperative central corneal thickness was measured by two examiners (E1, E2) with an ultrasound pachymeter and an OLCR pachymeter. Agreement and inter-rater repeatability were determined using the comparison method described by Bland and Altman. RESULTS: The limits of agreement between the two devices ranged from 17.8 microm (E1) to 20.5 microm (E2) preoperatively and from 22.4 microm (E1) to 16.9 microm (E2) postoperatively. The coefficient of inter-rater repeatability ranged from 9.1 microm (ultrasound pachymeter) to 5.4 microm (OLCR pachymeter) preoperatively and from 7.1 microm (ultrasound pachymeter) to 4.7 microm (OLCR pachymeter) postoperatively. CONCLUSIONS: The OLCR pachymeter seems to show better pre- and postoperative repeatability compared to the ultrasound pachymeter. The agreement between the two devices should be considered acceptable for clinical practice. Photorefractive keratectomy did not affect the postoperative agreement and repeatability of the pachymeters.