Obstructive Sleep Apnea and Primary Open-angle Glaucoma No abstract available

Obstructive Sleep Apnea in Patients With Primary-open Angle Glaucoma: No Role for a Screening Program Précis: In this study, we found a high prevalence of obstructive sleep apnea (OSA) among patients with primary open-angle glaucoma (POAG) but this was not different (nor was OSA more severe) to matched people without glaucoma. Rationale: It has been proposed that OSA might be a contributing factor in the development of POAG and by extension that there could be a role for screening people with POAG for OSA. Objectives: To assess whether the prevalence of OSA among patients with POAG is different from that in people without glaucoma and to examine for associations between apnea-hypopnea index (AHI) and markers of functional and structural changes in POAG. Methods: Unselected POAG patients and control subjects were consecutively recruited in a single center. A comprehensive ocular assessment and nocturnal multichannel cardiorespiratory monitoring were performed. Results: Data from 395 participants, 235 POAG patients, and 160 controls were analyzed. The prevalence of OSA was 58% [95% confidence interval (CI), 52-65] in POAG patients and 54% (95% CI, 47-62) in controls, with 22% (95% CI, 16-27) of POAG patients and 16% (95% CI, 11-22) of controls diagnosed with moderate or severe OSA. A total of 160 POAG participants were matched to the controls using propensity score matching. There was no significant difference in OSA prevalence between the matched groups (P=0.91 for AHI≥5 and P=0.66 for AHI≥15). The AHI was not associated with the severity of visual field defect or retinal nerve fiber layer thinning after adjustment for confounders. Conclusions: This study confirms a high prevalence of OSA among patients with POAG which is, however, not higher than in people without glaucoma matched for known OSA risk factors. Our results do not support screening for OSA in patients with POAG.

XEN Gel Stent in Pseudoexfoliative Glaucoma: 2-Year Results of a Prospective Evaluation Précis: This study confirms the safety and efficacy of XEN gel stents in the management of pseudoexfoliative glaucoma 2 years after implantation, with success rates similar to primary open-angle glaucoma regardless of the definition of success. Purpose: To compare the long-term safety and efficacy of XEN gel implant surgery (Allergan Inc., Irvine, CA) in patients with pseudoexfoliative glaucoma (PEXG) and primary open-angle glaucoma (POAG). Setting: Prospective, interventional study in a tertiary glaucoma center. Methods: A total of 110 eyes of 85 patients with POAG (57 eyes) or PEXG (53 eyes) and uncontrolled intraocular pressure (IOP) despite medical treatment underwent combined XEN+cataract surgery or standalone XEN surgery. Mean IOP, mean number of medications, needling rates, and incidence of adverse effects were compared between the 2 groups. Complete surgical success was defined as an unmedicated IOP≤12, 15, 16, or 18 mm Hg at 2 years, both with and without a 20% reduction from baseline. Results: Combined XEN+cataract surgery was performed in 72% of POAG and 76% of PEXG eyes (P=0.67), the remainder underwent standalone XEN surgery. Patient characteristics were similar between the 2 groups except for older age for the patients with PEXG (78.5±8.5 vs. 71.3±8.7 y; P<0.005). Mean medicated IOP were 19.8±5.8 mm Hg (POAG) versus 19.8±8.2 mm Hg (PEXG) at baseline (P=0.98), and 14.5±3.6 mm Hg (−26.8%) versus 14.2±3.8 mm Hg (−28.3%), respectively, at 2 years (P=0.75). Mean medications concomitantly dropped from 1.9±1.6 (POAG) versus 2.0±1.3 (PEXG) to 0.6±0.9 versus 0.4±0.7, respectively (P=0.29). Using the 16 mm Hg threshold, 51.4% (POAG) versus 57.1% (PEXG) eyes achieved complete success (P=0.70) at 2 years. The difference in success rates between the 2 groups was not statistically significant under any of the definitions of success. By 24 months, needling was performed in 42.8% (POAG) and 43.2% (PEXG) (P=0.64), with an average time to needling of 162.8 and 134.9 days, respectively (P=0.46). The rates of adverse effects were 30.6% (POAG) and 36.4% (PEXG) (P=0.66), and additional glaucoma surgeries were carried out in 14.3% (POAG) versus 15.9% (PEXG) (P=0.89). Conclusions: The XEN gel implant as a standalone or combined procedure demonstrated similar efficacy and safety results in PEXG and POAG eyes.

The Association Between Visual Field Reliability Indices and Cognitive Impairment in Glaucoma Patients Precis: This prospective cross-sectional study found that patients with cognitive impairment (CI) are more likely to produce unreliable visual field (VF) tests, especially with higher false-negative (FN) responses and consequent overestimation of mean deviation (MD). Aim: Aging-associated CI can impair the ability of individuals to perform a VF test and compromise the reliability of the results. We evaluated the association between neurocognitive impairment and VF reliability indices in glaucoma patients. Methods: This prospective, cross-sectional study was conducted in the Ophthalmology Department, Hospital Kuala Pilah, Malaysia, and included 113 eyes of 60 glaucoma patients with no prior diagnosis of dementia. Patients were monitored with the Humphrey Visual Field Analyzer using a 30-2 SITA, standard protocol, and CI was assessed using the clock drawing test (CDT). The relationships between the CDT score, MD, pattern standard deviation, Visual Field Index (VFI), fixation loss (FL), false-positive values, and FN values were analyzed using the ordinal regression model. Results: Glaucoma patients older than 65 years had a higher prevalence of CI. There was a statistically significant correlation between CDT scores and glaucoma severity, FL, FN, and VFI values (rs=−0.20, P=0.03; rs=−0.20, P=0.04; rs=−0.28, P=0.003; rs=0.21, P=0.03, respectively). In a multivariate model adjusted for age and glaucoma severity, patients with lower FN were significantly less likely to have CI (odds ratio, 0.91; 95% confidence interval, 0.89-0.93) and patients with higher MD were more likely to have CI (odds ratio, 1.10; 95% confidence interval, 1.05-1.16); false positive, FL, pattern standard deviation, and VFI showed no significant correlation. Conclusion: Cognitive decline is associated with reduced VF reliability, especially with higher FN rate and overestimated MD. Screening and monitoring of CI may be important in the assessment of VF progression in glaucoma patients.

Optic Nerve Tortuosity and Globe Proptosis in Normal and Glaucoma Subjects Précis: Eyes with glaucoma have tauter optic nerves compared with normal eyes, which may exert more force on the optic nerve head tissues during eye movements. Purpose: The purpose of this study was to assess the difference in optic nerve tortuosity during eye movements and globe proptosis between primary open angle glaucoma and normal subjects using orbital magnetic resonance imaging (MRI). Methods: Ten Chinese subjects matched for ethnicity and refractive errors were recruited, including 5 normal controls and 5 patients with primary open angle glaucoma. All subjects underwent MRI to assess their optic nerves and globes for 3 eye positions: primary gaze, adduction, and abduction. Optic nerve tortuosity (optic nerve length divided by the distance between 2 ends) and globe proptosis (maximum distance between the cornea and interzygomatic line) were measured from MRI images. Results: In adduction, the tortuosity of normal eyes was significantly larger than that of the glaucomatous eyes. Optic nerve tortuosity in adduction in the control and glaucoma groups were 1.004±0.003 (mean±SD) and 1.001±0.001, respectively (P=0.037). Globe proptosis (primary gaze) in glaucoma subjects (19.14±2.11 mm) was significantly higher than that in control subjects (15.32±2.79 mm; P=0.046). Conclusions: In this sample, subjects with glaucoma exhibited tauter optic nerves and more protruding eye globes compared with normal eyes. This may impact optic nerve head deformations in anatomically predisposed patients.

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.

Results From the First Teleglaucoma Pilot Project in Addis Ababa, Ethiopia Precis: A teleglaucoma case-finding model was utilized in Ethiopia using a high-risk case identification approach. An overall 7.9% of patients had definite glaucoma, and 13.8% were glaucoma suspects. Most cases could be managed medically. Background: This study was carried out to analyze disease prevalence and clinical referral pathways for high-risk patients assessed through a hospital-based teleglaucoma case-finding program. Methods: Patients over the age of 35 years were referred from outpatient diabetic and hypertensive clinics. Through a teleglaucoma consultation, a glaucoma specialist provided remote diagnosis and management recommendations. Patient referral pathways were analyzed. Part way through the program, frontline ophthalmic nurses and optometrists were empowered to refer patients to be seen by general ophthalmologists within a week if patients met high-risk criteria. Qualitative stakeholder feedback was also obtained. Results: A total of 1002 patients (53% female) were assessed with a mean age of 51.0±11.7 years. The prevalence of glaucoma and glaucoma suspects was 7.9% (79 cases) and 13.8% (138 cases), respectively. Retinopathy was found in 9.1%, with hypertensive retinopathy (2.7%) and diabetic retinopathy (2.5%) representing the majority of cases. Age-related macular degeneration was present in 1.5% and cataract in 16%. An overall 63% of cases were without organic eye disease. 35% of patients were referred to a general ophthalmologist, 0.7% to a glaucoma specialist (for surgery), 1.5% to a retina specialist, and 17.7% to an optometrist for further care. Qualitative analysis revealed that stakeholders felt the value of teleglaucoma would be in triaging patients requiring more urgent management and in identifying disease at an earlier stage. Conclusions: There is a high prevalence of glaucoma in Ethiopian patients assessed through this teleglaucoma program. This model and study have also demonstrated various principles behind telemedicine, such as the development of an intelligent triage system, case-finding for a variety of diseases, and consideration of optimal patient flow/referral pathways.

Diagnostic Capability of 3D Peripapillary Retinal Volume for Glaucoma Using Optical Coherence Tomography Customized Software Précis: The diagnostic capability of peripapillary retinal volume is similar to peripapillary retinal nerve fiber layer thickness for diagnosing glaucoma, but with fewer artifacts. Purpose: To compare the diagnostic capability of 3-dimensional peripapillary retinal volume (RV) versus 2-dimensional peripapillary retinal nerve fiber layer (RNFL) thickness for open-angle glaucoma. Patients and Methods: A retrospective cross-sectional analysis was conducted. A total of 180 subjects (113 open-angle glaucoma, 67 normal participants) had spectral domain optical coherence tomography volume scans and RNFL thickness measurements. Peripapillary RV values were calculated using a custom-designed program with 4 circumpapillary annuli (CA): CA1 had circle diameters of 2.5 and 3.5 mm; CA2, 3 and 4 mm; CA3, 3.5 and 4.5 mm; and CA4, 4 and 5 mm. Area under the receiver operating characteristic curves were calculated for global, quadrant, and octant regions for RV (CA1 to CA4) and RNFL thickness. Pair-wise comparisons were conducted. Artifacts rates were determined. Results: Mean age was 62.7±15.4 years, and 47.8% (86/180) were male. Among RV measurements, best diagnostic performances were for the smallest 2 annuli for inferior RV (CA1: 0.964, CA2: 0.955). Of the 4 annuli, CA1 had the highest diagnostic performance. Of specific regions, the inferior RV quadrant had the highest performance across CA1 to CA4. Peripapillary RV had similar diagnostic capability compared with RNFL thickness (P>0.05). The artifact rate per B-scan for RV was 6.0%, which was significantly lower compared with 2-dimensional RNFL thickness in the same patient population (32.2%, P<0.0001). Conclusions: The diagnostic capability of RV is similar to RNFL thickness for perimetric open-angle glaucoma, but RV had fewer artifacts compared with RNFL thickness.

Three-Dimensional Optical Coherence Tomography Imaging For Glaucoma Associated With Boston Keratoprosthesis Type I and II Precis: Three-dimensional (3D) spectral domain optical coherence tomography (OCT) volume scans of the optic nerve head (ONH) and the peripapillary area are useful in the management of glaucoma in patients with a type I or II Boston Keratoprosthesis (KPro). Purpose: The purpose of this study was to report the use of spectral domain OCT in the management of glaucoma in patients with a type I or II Boston KPro. Materials and Methods: This study is an observational case series. Four consecutive patients with KPro implants were referred for glaucoma evaluation. A comprehensive eye examination was performed which included disc photography, visual field testing, and high-density spectral domain OCT volume scans of the ONH and the peripapillary area. 2D and 3D parameters were calculated using custom-designed segmentation algorithms developed for glaucoma management. Results: Spectral domain OCT parameters provided useful information in the diagnosis and management of 4 KPro patients. OCT parameters which can be used in KPro patients included 2D retinal nerve fiber layer (RNFL) thickness, 3D peripapillary RNFL volume, 3D peripapillary retinal thickness and volume, 3D cup volume, and 3D neuroretinal rim thickness and volume. In 3 of 4 cases where the traditional 2D RNFL thickness scan was limited by artifacts, 3D spectral domain OCT volume scans provided useful quantitative objective measurements of the ONH and peripapillary region. Therefore, 3D parameters derived from high-density volume scans as well as radial scans of the ONH can be used to overcome the limitations and artifacts associated with 2D RNFL thickness scans. Conclusions: Spectral domain OCT volume scans offer the possibility to enhance the evaluation of KPro patients with glaucoma by using both 2D and 3D diagnostic parameters that are easily obtained in a clinic setting.

Microarchitecture of Schlemm Canal Before and After Cataract Extraction Surgery Precis: Schlemm canal (SC) expands after cataract extraction (CE), both in the area and in volume by 25% as was measured using enhanced-depth imaging optical coherent tomography (EDI-OCT) in patients before and 1 week after CE. Purpose: This study aims to characterize the structural and volume changes on the microstructure of SC in patients before and after uneventful phacoemulsification CE by using EDI-OCT. Materials and Methods: Forty-one serial horizontal EDI-OCT B-scans (interval between B-scans, 69 µm) were obtained in the nasal corneoscleral limbus before and 1 week after CE. The structure of aqueous channels, conjunctival blood vessels and iris anatomy in each scan were used as landmarks to select for overlapping scans taken before and following CE. The SC cross-section area was measured in each of the selected scans and SC volume was determined following a 3-dimensional reconstruction. Results: Eleven eyes (6 females and 5 males) were imaged successfully before and after CE. Mean age was 70.54±11.38 years. The mean axial length was 23.10±0.87 mm. After CE, the mean best-corrected visual acuity in logMAR improved from 0.4±0.13 to 0.2±0.13 (P=0.028). There was no significant change in the mean intraocular pressure before and after CE (15.09±1.33 to 15.0±2.16 mm Hg; P=0.39). The mean SC cross-section area increased by 25%, from 4744±376 to 5941±1048 μm2 (P<0.001). SC volume in the analyzed region increased by 25% from 6,641,473±585,954 to 8,317,909±1,328,809 μm3 (P<0.001). Conclusion: CE expands SC dimensions in healthy eyes. EDI-OCT imaging of SC may prove useful in the evaluation of the SC dimensions in vivo before and after CE.