PURPOSE: To analyze the repeatability of a new device measuring ocular biomechanical properties, central corneal thickness (CCT), and intraocular pressure (IOP) and to investigate these parameters and their correlations in healthy eyes. METHODS: Three consecutive measurements were performed on each eye using the CorVis ST device (Oculus Optikgeräte, Inc., Wetzler, Germany). Ten specific parameters, CCT, and IOP were measured. Biometric data were recorded with IOLMaster (Carl Zeiss Meditec, Jena, Germany). RESULTS: This study comprised 75 eyes of 75 healthy volunteers (mean age: 61.24 ± 15.72 years). Mean IOP was 15.02 ± 2.90 mm Hg and mean CCT was 556.33 ± 33.13 μ m. Intraclass correlation coefficient (ICC) was 0.865 for IOP and 0.970 for CCT, and coefficient of variation was 0.069 for IOP and 0.008 for CCT. ICC was 0.758 for maximum amplitude at highest concavity and 0.784 for first applanation time, and less than 0.6 for all other parameters. The device-specific data showed no significant relationship with age and axial length. Flattest and steepest keratometric values and IOP showed a significant correlation with the 10 device-specific parameters. CONCLUSIONS: The CorVis ST showed high repeatability for only IOP and pachymetric values. Single measurements are not reliable for the 10 device-specific parameters. The device allows for conducting clinical examinations and screening for surgeries altering ocular biomechanical properties with some form of averaging of multiple measurements. [ J Refract Surg. 2013;29(8):558–563.]

Purpose: The aim of this study was to quantify epithelial, stromal, and endothelial cell density, and subbasal nerve morphology in young patients with type 1 diabetes mellitus with and without diabetic retinopathy. Methods: A total of 28 young patients (mean age, 22.86 ± 9.05 years) with type 1 diabetes, with (n = 18) and without (n = 10) retinopathy, and 17 age-matched healthy control subjects (mean age, 26.53 ± 2.43 years) underwent corneal confocal microscopy (CCM). Results: We found significantly lower epithelial (P < 0.0001) and endothelial (P = 0.001) cell densities and higher keratocyte cell density (P = 0.024) in patients with type 1 diabetes compared to controls. Significantly lower corneal nerve fiber density (P = 0.004), nerve branch density (P = 0.004), total nerve branch density (P = 0.04), and nerve fiber length (P = 0.001), and greater nerve fiber width (P = 0.04) were observed in patients with type 1 diabetes compared to control subjects. Significantly lower epithelial (P < 0.001) and endothelial (P = 0.02) cell densities, nerve branch density (P = 0.02), and nerve fiber length (P = 0.04), and significantly higher keratocyte cell density (P = 0.02) were found in patients with type 1 diabetes without retinopathy compared to control subjects. Conclusions: Corneal confocal microscopy identifies corneal cellular and small nerve fiber pathology in young patients with type 1 diabetes without retinopathy, which increases in severity in those with retinopathy. Corneal confocal microscopy appears to have considerable use as an imaging biomarker for early subclinical pathology in young patients with type 1 diabetes mellitus.

To measure anterior chamber depth (ACD) with an anterior segment optical coherence tomography (AS-OCT) and a standard ultrasonic (US) axial scan (A-scan) device using an immersion technique and to assess repeatability, reproducibility, and correlations of the measurements. Department of Ophthalmology, Medical Health and Science Center, University of Debrecen, Debrecen, Hungary. Sixty healthy eyes of 41 patients were enrolled in a study. The central ACD was measured 5 times with AS-OCT (Visante, Carl Zeiss Meditec) using its chamber tool and 5 times with a US A-scan device (UltraScan Imaging System, Alcon Laboratories) using an immersion method. The measurements were performed consecutively by 2 independent observers. The mean ACD measured with AS-OCT was 3.12 mm +/- 0.33 (SD) by observer 1 and 3.11 +/- 0.33 mm by observer 2 (P = .78). The repeatability was 0.8% +/- 0.4% and 1.9% +/- 1.4%, respectively. The reproducibility was 0.23%. The reliability coefficient with AS-OCT was 99.6%. The mean ACD measured with immersion US A-scan was 2.98 +/- 0.33 mm by observer 1 and 2.95 +/- 0.34 mm by observer 2 (P = .68) . The repeatability was 6.4% +/- 3.8% by observer 1 and 8.5% +/- 4.9% by observer 2. The reproducibility was 0.88%. The reliability coefficient was 87.1% for US A-scan measurements. The difference between ACD values with AS-OCT and values with US A-scan was statistically significant (P = .02). The correlation (r) between AS-OCT and US A-scan was 0.732 (P<.0001) by observer 1 and 0.802 (P<.0001) by observer 2. Anterior chamber measurements were significantly deeper with AS-OCT than with US immersion A-scan. Repeatability of ACD measurements was better with AS-OCT than with immersion US, and reproducibility was equal with the 2 methods.

To compare anterior chamber depth (ACD) measurements with a new optical device with those taken with a standard ultrasound (US) device in emmetropic phakic and pseudophakic eyes. Department of Ophthalmology, Medical Health and Science Center, University of Debrecen, Debrecen, Hungary. Forty-two phakic and 42 pseudophakic patients with normal axial lengths (mean 22.91 mm +/- 1.21 [SD]) were enrolled in the study. The ACD was measured 3 times with Scheimpflug-based Pentacam (Oculus) and then 3 times with a standard A-scan US device (AL-2000, Tomey). The data were then analyzed. In the phakic group, the mean ACD was 2.87 +/- 0.4 mm with the Pentacam and 2.89 +/- 0.49 mm with ultrasound A-scan (US) (P = .84). In the pseudophakic group, the mean ACD was 3.41 +/- 0.28 mm and 3.97 +/- 0.45 mm, respectively (P < .001). The correlation between measurements was significant in both the phakic and pseudophakic groups (r = .547/P < .001 and r = .404/P = .01, respectively). In phakic eyes, ACD measured with the Pentacam and with US was the same. However, in pseudophakic eyes, the difference was significantly lower when the ACD was measured with the Pentacam. Therefore, in pseudophakic patients, further evaluation of ACD data with the Scheimpflug-based system is necessary.

Purpose: Our aim was to assess the corneal power, axis, and age dependence of the anterior and posterior corneal surfaces with Scheimpflug imaging. Methods: Patients older than 10 years without a history of ocular surgery, corneal diseases, contact lens wearing, or severe dry eye were enrolled. Data regarding the anterior and posterior cornea were analyzed by means of Scheimpflug imaging (Pentacam HR). Results: The median age was 46.8 years (range: 10.0–90.3), and involved 827 eyes of 827 patients. Posterior corneal astigmatism was a median of −0.30 diopters (D) and exceeded 0.50 D in 12.56%. The ratio of the anterior-to-posterior corneal radius was a median of 1.217 (range: 1.021–1.402). The correlation between this ratio and age was significant (r = −0.219; P < 0.001). The correlation between anterior and posterior corneal astigmatism and age was significant. At the anterior surface, the ratio of with-the-rule astigmatism was 80.0% for the age range 10 to 20, decreasing to 36.0% for those aged over 81 years, whereas the ratio of against-the-rule astigmatism increased from 7.1% to 44.0%. At the posterior surface, the ratio of with-the-rule astigmatism was 94.3% for the age range 10 to 20 years, decreasing to 84.0% for those aged over 81 years, whereas the ratio of against-the-rule astigmatism increased from 1.4% to 8.0%. Conclusions: The posterior cornea significantly influences corneal astigmatism. Its power value and orientation are much more stable with advancing age compared with anterior surface values.