Comparison between the Correlations of Retinal Nerve Fiber Layer Thickness Measured by Spectral Domain Optical Coherence Tomography and Visual Field Defects in Standard Automated White-on-White Perimetry versus Pulsar Perimetry

Purpose. To compare the structure-function relationships between retinal nerve fiber layer thickness (RNFLT) and visual field defects measured either by standard automated perimetry (SAP) or by Pulsar perimetry (PP). Materials and Methods. 263 eyes of 143 patients were prospectively included. Depending on the RNFLT, patients were assigned to the glaucoma group (group A: RNFL score 3–6) or the control group (group B: RNFL score 0–2). Structure-function relationships between RNFLT and mean sensitivity (MS) measured by SAP and PP were analyzed. Results. Throughout the entire group, the MS assessed by PP and SAP correlated significantly with RNFLT in all sectors. In the glaucoma group, there was no significant difference between the correlations RNFL-SAP and RNFL-PP, whereas a significant difference was found in the control group. Conclusions. In the control group, the correlation between structure and function based on the PP data was significantly stronger than that based on SAP

Accuracy of Measurements With the iCare HOME Rebound Tonometer

Purpose: To evaluate the accuracy of intraocular pressure (IOP) measurements obtained with the newly available iCare HOME (RTHOME) rebound tonometer compared with the iCare ONE (RTONE) tonometer and Goldmann applanation tonometry (GAT), and possible correlation with central corneal thickness (CCT). Materials and Methods: IOP measurements were obtained from 154 patients by an ophthalmologist (doc) using each of the above-mentioned tonometers. In addition, patients (pat) measured their own IOP with the RTHOME and RTONE. The means and SD of results obtained with the different tonometers were compared. Agreement between the tonometers was calculated using the Bland-Altman method. Results: Mean IOPs for the right eyes only were 15.9 +/- 6.4 mm Hg (RTONEdoc), 15.8 +/- 6.4 mm Hg (RTONEpat), 15.0 +/- 5.9 mm Hg (RTHOMEdoc), 14.9 +/- 6.3 mm Hg (RTHOMEpat), and 15.8 +/- 4.4 mm Hg (GAT). Bland-Altman analysis revealed mean differences (bias) between RTONEdoc and RTHOMEdoc, between RTHOMEdoc and RTHOMEpat, and between RTHOMEdoc and GAT of 0.8, 0.1, and -0.8 mm Hg, respectively, with 95% limits of agreement of -3.5 to 5.2, -4.9 to 5.1, and -7.2 to 5.6 mm Hg, respectively. Linear regression of the comparisons revealed a proportional error over the range of pressures examined in the case of RTHOMEdoc versus GAT (slope = 0.32, P < 0.001). Considering the data from all eyes, the difference between RTHOMEdoc and GAT correlated significantly with the CCT (P = 0.01). Conclusion: RTHOME readings correlate well with the GAT results although some limitations such as dependency of readings on CCT and increasing differences at lower and higher IOP levels need to be taken into account

Assessing the validity of corneal power estimation using conventional keratometry for intraocular lens power calculation in eyes with Fuch’s dystrophy undergoing Descemet membrane endothelial keratoplasty

Purpose!#!The present retrospective study was designed to test the hypothesis that the postoperative posterior to preoperative anterior corneal curvature radii (PPPA) ratio in eyes with Fuch's dystrophy undergoing Descemet membrane endothelial keratoplasty (DMEK) is significantly different to the posterior to anterior corneal curvature radii (PA) ratio in virgin eyes and therefore renders conventional keratometry (K) and the corneal power derived by it invalid for intraocular lens (IOL) power calculation.!##!Methods!#!Measurement of corneal parameters was performed using Scheimpflug imaging (Pentacam HR, Oculus, Germany). In 125 eyes with Fuch's dystrophy undergoing DMEK, a fictitious keratometer index was calculated based on the PPPA ratio. The preoperative and postoperative keratometer indices and PA ratios were also determined. Results were compared to those obtained in a control group consisting of 125 eyes without corneal pathologies. Calculated mean ratios and keratometer indices were then used to convert the anterior corneal radius in each eye before DMEK to postoperative posterior and total corneal power. To assess the most appropriate ratio and keratometer index, predicted and measured powers were compared using Bland-Altman plots.!##!Results!#!The PPPA ratio determined in eyes with Fuch's dystrophy undergoing DMEK was significantly different (P &amp;lt; 0.001) to the PA ratio in eyes without corneal pathologies. Using the mean PA ratio (0.822) and keratometer index (1.3283), calculated with the control group data to convert the anterior corneal radius before DMEK to power, leads to a significant (P &amp;lt; 0.001) underestimation of postoperative posterior negative corneal power (mean difference (∆ = - 0.14D ± 0.30) and overestimation of total corneal power (∆ = - 0.45D ± 1.08). The lowest prediction errors were found using the geometric mean PPPA ratio (0.806) and corresponding keratometer index (1.3273) to predict the postoperative posterior (∆ = - 0.01 ± 0.30) and total corneal powers (∆ = - 0.32D ± 1.08).!##!Conclusions!#!Corneal power estimation using conventional K for IOL power calculation is invalid in eyes with Fuch's dystrophy undergoing DMEK. To avoid an overestimation of corneal power and minimize the risk of a postoperative hyperopic shift, conventional K for IOL power calculation should be adjusted in eyes with Fuch's dystrophy undergoing cataract surgery combined with DMEK. The fictitious PPPA ratio and keratometer index may guide further IOL power calculation methods to achieve this

Changes in Flow Density Measured Using Optical Coherence Tomography Angiography after iStent Insertion in Combination with Phacoemulsification in Patients with Open-Angle Glaucoma

Purpose. To evaluate changes in flow density after the implantation of a trabecular microbypass stent (iStent) in combination with cataract surgery. Methods. A total of 48 eyes of 48 patients, who underwent either cataract surgery alone (cataract group) or cataract surgery with implantation of two iStent inject devices (iStent group), were prospectively included in this study. Intraocular pressure (IOP) and flow density data before and after surgery were extracted and analyzed. Results. In the iStent group, the mean IOP was 18.2 ± 3.3 mmHg prior to surgery and 13.2 ± 2.3 at follow-up, and this difference was statistically significant (p<0.001). The mean IOP in the cataract group also improved significantly after surgery (before: 17.1 ± 2.4; after: 15.1 ± 2.7 p=0.003). The flow density (whole en face) in the superficial and deep retinal OCT angiogram of the macula (superficial: p=0.002; deep: p=0.034) and in the ONH (p=0.011) improved significantly after surgery in the iStent group. The differences in the cataract group were not significant. Conclusions. Flow density of the macula and ONH, as measured by OCTA, improved significantly after cataract surgery with iStent. Noninvasive quantitative analyses of flow density provide a new parameter, which can help for the monitoring of therapy success after glaucoma surgery