Evaluating the Laser Output of the Micropulse P3 Laser Delivery Device Following Repeated Use.

PRECIS: Repeated use of the Micropulse P3 (MP3) probe during micropulse transscleral cyclophotocoagulation is associated with an increase in laser output over time. PURPOSE: The purpose of this study was to examine the laser efficacy of the MP3 probe following repeated use. METHODS: This was an observational study carried out using Cyclo G6 Glaucoma Laser System with 6 MP3 laser delivery probes. Each probe was fired for 100 seconds, every 10 minutes until the probe was deactivated. The laser output was measured using a laser power meter. Maximum observed laser power output was also noted. RESULTS: All probes were deactivated after 90 minutes (9 cycles) of use. Mean laser output of all 6 probes was determined, and results suggested an increase in output with time. When examining the differences in total laser output for each cycle, no significant differences were observed for the first 4 cycles, but not for the remaining 5 cycles, wherein the increased laser outputs were found to be significantly different from baseline (cycle 1). CONCLUSION: Findings suggest a possible increase in laser output with repeated use, especially after 4 cycles, and clinicians need to be cautious if they intend to use the probes repeatedly.

Reliability of Graders and Comparison with an Automated Algorithm for Vertical Cup-Disc Ratio Grading in Fundus Photographs.

INTRODUCTION: We aimed to investigate the intergrader and intragrader reliability of human graders and an automated algorithm for vertical cup-disc ratio (CDR) grading in colour fundus photographs. MATERIALS AND METHODS: Two-hundred fundus photographs were selected from a database of 3000 photographs of patients screened at a tertiary ophthalmology referral centre. The graders included glaucoma specialists (n = 3), general ophthalmologists (n = 2), optometrists (n = 2), family physicians (n = 2) and a novel automated algorithm (AA). In total, 2 rounds of CDR grading were held for each grader on 2 different dates, with the photographs presented in random order. The CDR values were graded as 0.1-1.0 or ungradable. The grading results of the 2 senior glaucoma specialists were used as the reference benchmarks for comparison. RESULTS: The intraclass correlation coefficient values ranged from 0.37-0.74 and 0.47-0.97 for intergrader and intragrader reliability, respectively. There was no significant correlation between the human graders' level of reliability and their years of experience in grading CDR (P = 0.91). The area under the curve (AUC) value of the AA was 0.847 (comparable to AUC value of 0.876 for the glaucoma specialist). Bland Altman plots demonstrated that the AA's performance was at least comparable to a glaucoma specialist. CONCLUSION: The results suggest that AA is comparable to and may have more consistent performance than human graders in CDR grading of fundus photographs. This may have potential application as a screening tool to help detect asymptomatic glaucoma-suspect patients in the community.