Corneal Parameters in Healthy Subjects Assessed by Corvis ST.

PURPOSE: To evaluate corneal biomechanics using Corvis ST in healthy eyes from Iranian keratorefractive surgery candidates. METHODS: In this prospective consecutive observational case series, the intraocular pressure (IOP), central corneal thickness (CCT), and biomechanical properties of 1,304 eyes from 652 patients were evaluated using Corvis ST. Keratometric readings and manifest refraction were also recorded. RESULTS: The mean ( ± SD) age of participants was 28 ± 5 years, and 31.7% were male. The mean spherical equivalent refraction was -3.50 ± 1.57 diopters (D), the mean IOP was 16.8 ± 2.9 mmHg, and the mean CCT was 531 ± 31 µ m for the right eye. The respective means ( ± SD) corneal biomechanical parameters of the right eye were as follows: first applanation time: 7.36 ± 0.39 milliseconds (ms); first applanation length: 1.82 ± 0.22 mm; velocity in: 0.12 ± 0.04 m/s; second applanation time: 20.13 ± 0.48 ms; second applanation length: 1.34 ± 0.55 mm; velocity out: -0.67 ± 0.17 m/s; total time: 16.84 ± 0.64 ms; deformation amplitude: 1.05 ± 0.10 mm; peak distance: 4.60 ± 1.01 mm; and concave radius of curvature: 7.35 ± 1.39 mm. In the linear regression analysis, IOP exhibited a statistically significant association with the first and second applanation times, total time, velocity in, peak distance, deformation amplitude, and concave radius of curvature. CONCLUSION: Our study results can be used as a reference for the interpretation of Corvis ST parameters in healthy refractive surgery candidates in the Iranian population. Our results confirmed that IOP is a major determinant of Corvis parameters.

Traumatic optic neuropathy treatment trial (TONTT): open label, phase 3, multicenter, semi-experimental trial.

PURPOSE: Intravenously administered erythropoietin (EPO) was firstly commenced (phase 1) in patients with indirect traumatic optic neuropathy (TON) by this group in 2011. It was re-tested by another group (phase 2) in 2014. This multicenter clinical trial was designed to compare its effect with intravenous steroid and observation. METHODS: Included were TON patients ≥5 years of age and with trauma-treatment interval of ≤3 weeks. Follow-up visits were set at 1, 2, 3, 7, 14, 30, and at least 90 days after treatment. EPO and methylprednisolone were infused intravenously every day for three consecutive days. Primary outcome measure was change in the best corrected visual acuity (BCVA). Secondary outcomes included change in color vision and relative afferent pupillary defect (RAPD), side effects, and factors affecting the final visual improvement. RESULTS: Out of 120 patients, 100 (EPO: 69, steroid: 15, observation: 16) were finally included. All three groups showed a significant improvement of BCVA which was not significantly different between the groups (adjusted for pretreatment BCVA). Color vision was significantly improved in the EPO group. Late treatment (>3 days) (odds ratio = 2.53) and initial BCVA of NLP (odds ratio = 5.74) significantly worsened visual recovery. No side effect was observed in any group. CONCLUSION: EPO, steroid, and observation showed a significant improvement of BCVA in patients with TON. Initial BCVA of NLP and late treatment (>3 days) were significant risk factors for visual improvement.

Agreement of Corneal Diameter Measurements Obtained by a Swept-source Biometer and a Scheimpflug-based Topographer.

PURPOSE: To assess the agreement between a swept-source optical biometry device (IOLMaster 700) and a Scheimpflug-based topography device (Pentacam HR) in measuring the corneal diameter. METHODS: A total of 100 eyes from 100 cataract surgery candidates were enrolled. The white-to-white (WTW) distance measurements provided by both devices were recorded and analyzed. A paired t test was performed to compare the mean values of the WTW distance between the IOLMaster 700 and Pentacam HR. The Bland-Altman analysis was used to evaluate the agreement between the measurements of both devices. RESULTS: Mean age (±SD) of the participants was 65.9 ± 3.3 years, and 58 (58%) were men. The mean WTW distances measured by the IOLMaster 700 and Pentacam HR were 11.72 ± 0.45 mm and 11.41 ± 0.42 mm, respectively (P < 0.001). The overall 95% limits of agreement were -0.17 and 0.78 mm. The 95% limits of agreement between the measurements of the 2 devices were -0.30 and 0.84 versus -0.07 and 0.72 for eyes with WTW distances of ≤11.50 mm versus >11.50 mm, respectively. CONCLUSIONS: According to the results of this study, the IOLMaster 700 may overestimate the WTW distance measurements by up to 0.78 mm compared with the Pentacam HR, so these 2 devices should not be used interchangeably for this purpose. The agreement is somehow weaker for eyes with WTW distances of 11.50 mm or less than those with WTW distances greater than 11.50 mm.