A Prospective Evaluation of the Repeatability and Reliability of New Steady-state Pattern Electroretinogram Parameters.

PURPOSE: The purpose of this study was to determine the repeatability and reproducibility of a new Pattern Electroretinography (PERG) device in healthy subjects. METHODS: A total of 40 eyes of 20 healthy subjects (45.6±6.8 y, 70% female) were enrolled in this prospective study. Steady-state PERG were recorded using the Diopsys NOVA (Diopsys Inc., NJ) to obtain the Magnitude, MagnitudeD, MagnitudeD/Magnitude Ratio, and Signal to Noise Ratio. Subjects underwent 2 "contrast sensitivity" protocols with the same electrodes and 2 after changing electrodes, by a single examiner. Eyes were stimulated separately using high and low contrast patterns. The same examination was repeated by a different operator following the same protocol 6 months after the baseline measures. Repeatability and reproducibility of the readings were calculated using intraclass correlation coefficient (ICC). A Bland-Altman plot was used to analyze the agreement between measures. RESULTS: ICC of Magnitude, MagnitudeD, MagnitudeD/Magnitude ratio, and SNR were 0.87, 0.81, 0.36, and 0.81, respectively between measures taken with the same electrodes (repeatability). After changing electrodes, ICC of the Magnitude, MagD, MagD/Mag ratio, and SNR were 0.79, 0.85, 0.51, and 0.83, respectively during the same session as baseline measures, and 0.87, 0.85, 0.40, and 0.76 when repeated after 6 months (reproducibility). The variability of MagD/Mag ratio increased with successive test repetitions. CONCLUSIONS: Mag, MagD, and SNR were repeatable and reproducible, whereas the MagD/Mag ratio was less repeatable and reproducible. These results suggest that the former parameters are sufficiently reliable to be used in clinical practice.

Prospective Evaluation of Standalone XEN Gel Implant and Combined Phacoemulsification-XEN Gel Implant Surgery: 1-Year Results.

PURPOSE: To evaluate the safety and efficacy of XEN gel implant (Allergan Inc., Irvine) as a standalone versus combined XEN-Phacoemulsification surgery (XEN+cataract) in glaucoma patients. METHODS: Prospective, interventional study. One-hundred forty-nine eyes (113 patients) with open-angle glaucoma and uncontrolled intraocular pressure (IOP) despite medical treatment were enrolled at a tertiary glaucoma center and followed up for a minimum of 1 year. Approximately two-thirds of patients underwent combined XEN+cataract surgery, while the remainder had XEN alone surgery. Primary outcome was a 20% or more decrease in IOP from medicated baseline at 1 year. Mean IOP, mean number of medications at last follow-up, and incidence of adverse effects were analyzed. RESULTS: Of 149 enrolled eyes, data of 87 (58%) were available at 1 year. A total of 109 (73.2%) eyes underwent XEN+cataract surgery and 40 (26.8%) XEN alone surgery. Mean medicated IOP was 20.0±7.1 at baseline and 13.9±4.3 mm Hg at 1 year (P<0.01), a 31% IOP reduction. Mean medications dropped from 1.9±1.3 preoperatively to 0.5±0.8 at 1 year (P<0.001). In total, 62.1% of patients achieved a ≥20% IOP reduction; this proportion was higher in the XEN alone group. 57.7% of eyes achieved complete success (without any antiglaucoma medications) and 71.1% qualified success (with or without medications) when IOP<16 mm Hg was considered as the definition of success. In all, 37% of patients required needling intervention. Adverse effects included bleb revision in 5 eyes, choroidal detachment in 2 eyes, and second glaucoma surgery in 9 eyes. CONCLUSIONS: The XEN gel implant as a standalone procedure or combined with cataract surgery demonstrated safe and sustained IOP reduction after 1 year.