A Novel Automated Visual Acuity Test Using a Portable Head-mounted Display.

SIGNIFICANCE: We developed a head-mounted display (HMD) as an automated way of testing visual acuity (VA) to increase workplace efficiency. This study raises its potential utility and advantages, analyzes reasons for its current limitations, and discusses areas of improvement in the development of this device. PURPOSE: Manual VA testing is important but labor-intensive in ophthalmology and optometry clinics. The purpose of this exploratory study is to assess the performance and identify potential limitations of an automated HMD for VA testing. METHODS: Sixty patients from National University Hospital, Singapore, were enrolled in a prospective observational study. The HMD was constructed based on the Snellen chart, with single optotypes displayed at a time. Each subject underwent VA testing of both eyes with the manual Snellen chart tested at 6 m from the subject and the HMD. RESULTS: Fifty-three subjects were included in the final analysis, with an incompletion rate of 11.7% (n = 7). The mean difference in estimated acuity between the HMD and Snellen chart was 0.05 logMAR. However, 95% limits of agreement were large at ±0.33 logMAR. The HMD overestimated vision in patients with poorer visual acuities. In detecting VA worse than 0.30 logMAR (6/12), sensitivity was 63.6% (95% confidence interval, 0.31 to 0.89%), and specificity was 81.0% (95% confidence interval, 0.66 to 0.91%). No significant correlation existed between mean difference and age (r = -0.15, P = .27) or education level (r = 0.04, P = .76). CONCLUSIONS: Advantages of our novel HMD technology include its fully automated nature and its portability. However, the device in its current form is not ready for widespread clinical use primarily because of its low accuracy, which is limited by both technical and user factors. Future studies are needed to improve its accuracy and completion rate and to evaluate for test-retest reliability in a larger population.

Two-Year Outcomes of the Paul Glaucoma Implant for Treatment of Glaucoma.

PURPOSE: To determine 2-year efficacy of the PAUL Glaucoma Implant (PGI), a novel glaucoma tube shunt in patients with advanced glaucoma. PARTICIPANTS: Patients with glaucoma refractory to maximum medical therapy or previous failed glaucoma surgery. METHODS: Retrospective review of all patients who had underwent PGI implantation in a single tertiary institution between May 1, 2017 and March 30, 2021. MAIN OUTCOME MEASURES: Primary outcome measure was failure defined as intraocular pressure (IOP) >18 mm Hg or <6 mm Hg on 2 consecutive visits after 3 months, reoperation for IOP-related indication, explantation of implant or loss of light perception vision. Complete success was defined as unmedicated IOP ≤18 mm Hg or ≥6 mm Hg in the absence of failure. RESULTS: Forty-five eyes in 45 patients were identified, with mean follow-up duration of 24.9±2.0 months. Thirty patients (66.7%) had primary glaucoma and 11 (24.4%) with previous glaucoma surgery. At 2 years following surgery, 8 eyes (17.8%) fulfilled the failure criteria with 32 eyes (71.1%) achieving complete success. Compared with mean medicated preoperative IOP (19.8±6.3 mm Hg), postoperative IOP at 24 months was 13.9±3.7 (P<0.01). Mean number of medications decreased from 3.2±0.8 preoperatively to 0.29±0.65 at 24 months (P<0.01). Significant complications included self-limiting shallow anterior chamber (n=10; 22.2%), hypotony requiring intervention (n=4; 8.9%) and tube occlusion (n=4; 8.9%). CONCLUSIONS: The PGI was able to achieve sustained IOP reduction with reduction of medications at 2 years postsurgery in patients with advanced glaucoma.

Comparison of refractive outcomes after combined cataract and glaucoma surgery: trabeculectomy and glaucoma drainage device implantation.

PURPOSE: To investigate the refractive outcome of combined cataract surgery and glaucoma drainage device (GDD) implantation compared with trabeculectomy and cataract surgery. SETTING: Department of Ophthalmology, National University Health System, Singapore. DESIGN: Retrospective cohort study. METHODS: 206 eyes were enrolled for analysis: 50 had combined cataract surgery and trabeculectomy (trabeculectomy group), 50 had combined cataract surgery and GDD implantation (GDD group), and 106 had cataract surgery alone (control group). Refractive prediction error and absolute prediction error of each glaucoma surgery group were compared with the control group. Subgroup analysis was performed in the following axial length (AL) subgroups: short (<22.5 mm), medium (≥22.5 to <25.5 mm), and long (≥25.5 mm). RESULTS: In total, 206 eyes were examined. There was no statistically significant difference in the overall refractive prediction error between the GDD (0.00 ± 0.54 diopters [D]) and the control group (0.10 ± 0.53 D, P = .58). There was significant myopic refractive prediction error in the trabeculectomy group (-0.18 ± 0.88 D, P = .020). In eyes with short AL, a greater absolute prediction error was observed in the GDD group (-0.75 ± 0.43 D, P = .039). CONCLUSIONS: Apart from a significant deviation in short AL eyes, combined cataract surgery and GDD implantation demonstrated no significant postoperative refractive prediction error.