Steady-State Pattern Electroretinography in Eyes with Glaucoma and High Myopia

Purpose

To investigate features of the steady-state pattern electroretinogram (ssPERG) in subjects with glaucoma (G), high myopia (HM; spherical equivalent ≤-6D) and glaucoma with high myopia (GHM).

Patients and Methods

Our study included 48 participants divided into 3 groups (G, HM, and GHM) who each underwent monocular ssPERG testing with Diopsys NOVA PERG protocols. The ConStim protocol detects distinct topographic patterns of dysfunction 16° and 24° around the central macula. MagD is the amplitude of the average signal and MagD/Mag ratio indicates the consistency of the response. ssPERG indices were compared between groups and correlated with functional (ie, visual field mean deviation (VFMD)) and structural (ie, average retinal nerve fibre layer (RNFL) thickness; Cirrus optical coherence tomography) features.

Results

Participants had an average age of 59.4±7.6 years. Mean Humphrey VFMD was -14.22 ± 2.88dB, -2.62 ± 1.18dB and -12.80 ± 2.60dB for G, HM and GHM groups, respectively. Mean RNFL thickness was 63.0 ± 8.20μm, 69.5 ± 15.7μm and 60.6 ± 5.0μm for G, HM and GHM groups, respectively. For the 24° setting, no significant differences were noted for any of the parameters. For the 16° setting, MagD was lower in the GHM group compared to the HM group (0.29µV vs 0.52µV; p = 0.02). Significant differences were noted for the MagD/Mag ratio between HM and G groups (0.58 vs 0.40; p = 0.02) and between HM and GHM groups (0.58 vs 0.35; p = 0.002). There were positive correlations between both MagD 16° and MagD/Mag ratio 16° with VFMD (correlation coefficient [r]=0.37, p = 0.009; and r = 0.44, p = 0.002, respectively) and RNFL (r = 0.43, p = 0.002; and r = 0.48, p = 0.001, respectively).

Conclusion

MagD/Mag ratio at 16° was significantly lower in glaucomatous eyes (with or without high myopia) compared to those with high myopia without glaucoma, suggesting that glaucoma has a distinct impact on MagD/Mag ratio at 16° irrespective of the presence of myopia.

Development and Validation of a Preference-Based Glaucoma Utility Instrument Using Discrete Choice Experiment

Importance

A glaucoma-specific instrument for estimating utilities across the spectrum of glaucoma severity is currently lacking, hindering the assessment of the cost-effectiveness of glaucoma treatments.

Objective

To develop and validate the preference-based Glaucoma Utility Instrument (Glau-U) and to ascertain the association between Glau-U utilities and severity of glaucoma and vision impairment.

Design, Setting, and Participants

This cross-sectional study was conducted in 2 stages at the Singapore National Eye Centre glaucoma clinics. Stage 1 focused on the identification and pretesting of the Glau-U attributes and was carried out between June 2009 and May 2016. Stage 2 involved the development and administration of the discrete choice experiment (DCE) survey and tasks and was conducted between May 7, 2018, and December 11, 2019. Stage 2 participants were English- or Mandarin-speaking Singaporean citizens or permanent residents of Chinese, Malay, or Indian ethnicity who were 40 years or older and had a clinical diagnosis of glaucoma in at least 1 eye.

Exposures

Glau-U comprised 6 quality-of-life attributes: activities of daily living, lighting and glare, movement, eye discomfort, other effects of glaucoma, and social and emotional effects. The descriptions or response options for these attributes were no difficulty or never, some difficulty or sometimes, or severe difficulty or often.

Main Outcomes and Measures

Utility weights for Glau-U were developed using a DCE questionnaire, which was interviewer administered to participants. Mixed logit regression determined utility weights for each health state. Glau-U utility weights across better- or worse-eye glaucoma and vision impairment severity were calculated using 1-way analysis of variance. Correlations between Glau-U utilities and better- or worse-eye visual fields and EuroQol 5-Dimension utilities were ascertained to assess convergent and divergent validity.

Results

Of the 304 participants (mean [SD] age, 68.3 [8.7] years; 182 men [59.9%]), 281 (92.4%) had no vision impairment in the better eye, 13 (4.3%) had mild impairment, and 10 (3.3%) had moderate to severe vision impairment. Mean (SD) Glau-U utilities decreased as better-eye glaucoma severity increased (none: 0.73 [0.21]; mild: 0.66 [0.21]; moderate: 0.66 [0.20]; severe: 0.60 [0.28]; and advanced or end-stage: 0.22 [0.38]; P < .001), representing reductions of 20.7% to 76.1% in quality-adjusted life-years compared with a health state that included preperimetric glaucoma. Mean (SD) Glau-U utilities also decreased as better-eye vision impairment worsened from 0.67 (0.23) for none to 0.58 (0.32) for mild to 0.46 (0.29) for moderate to severe vision impairment. Glau-U utilities demonstrated moderate correlations with better-eye (r = 0.34; P < .001) and worse-eye (r = 0.33; P < .001) mean deviation scores and low correlations with EuroQol 5-Dimension utilities (r = 0.22; P < .001), supporting convergent and divergent validity.

Conclusions and Relevance

Use of Glau-U revealed large decrements in utility that were associated with late-stage glaucoma, suggesting that this new instrument may be useful for cost-effectiveness analyses of interventions and informing resource allocation policies for glaucoma and vision loss.

The Effect of Medical Lowering of Intraocular Pressure on Peripapillary and Macular Blood Flow as Measured by Optical Coherence Tomography Angiography in Treatment-naive Eyes

PRCIS

Reduction of intraocular pressure (IOP) by latanoprost in treatment-naive eyes is significantly correlated to an increase in vessel density (VD) at the optic nerve head (ONH).

PURPOSE

To evaluate the effect of topical latanoprost on ocular microvasculature using optical coherence tomography angiography (OCTA).

PATIENTS AND METHODS

In this prospective case-control study, 26 eyes from 18 treatment-naive subjects in whom prostaglandin analogue (PGA) latanoprost 0.005% was initiated were included as cases. In 10 out of the 18 subjects, medication was initiated in only 1 eye; their contralateral untreated eyes were used as controls. OCTA (AngioVue, Optovue Inc., Fremont, CA) was performed at baseline and ≥3 weeks after commencing treatment. Main outcome measures were change in flow area and VD at the ONH, radial peripapillary capillaries (RPC), and macula. Comparison between the 2 visits was performed using a linear mixed model adjusted for intereye correlation and mean ocular perfusion pressure.

RESULTS

IOP decreased by 26.1%±11.3% (P<0.001) in the cases and 0.18%±12.2% (P=0.63) in controls. Significant correlations between change in IOP and change in ONH VD (correlation coefficient [r]=-0.42, P=0.04), and between change in IOP and change in RPC VD (r=-0.48, P=0.02) were observed in the cases, whereas none were observed in the controls. When multiple testing was considered, no significant changes in flow area and VD were observed in cases and controls.

CONCLUSIONS

The reduction of IOP by a PGA in treatment-naive eyes was significantly correlated to the increase in ONH VD and RPC VD. This may indicate a mechanism by which IOP reduction modulates the risk of glaucoma progression by improving ocular microperfusion.

Segregation of neuronal-vascular components in a retinal nerve fiber layer for thickness measurement using OCT and OCT angiography

Assessment of the circumpapillary retinal nerve fiber layer (RNFL) provides crucial knowledge on the status of the optic nerve. Current circumpapillary RNFL measurements consider only thickness, but an accurate evaluation should also consider blood vessel contribution. Previous studies considered the presence of major vessels in RNFL thickness measurements from optical coherence tomography (OCT). However, such quantitative measurements do not account for smaller vessels, which could also affect circumpapillary RNFL measurements. We present an approach to automatically segregate the neuronal and vascular components in circumpapillary RNFL by combining vascular information from OCT angiography (OCTA) and structural data from OCT. Automated segmentation of the circumpapillary RNFL using a state-of-the-art deep learning network is first performed and followed by the lateral and depth-resolved localization of the vascular component by vertically projecting the vessels along the circular scan from OCTA vessels map onto the segmented RNFL. Using this proposed approach, we compare the correlations of circumpapillary RNFL thicknesses with age at different levels of vessel exclusion (exclusion of major vessels only vs both major- and micro-vessels) and also evaluate the thickness variability in 75 healthy eyes. Our results show that the ratio of major- and micro-vessels to circumpapillary RNFL achieved a stronger correlation with aging (r = 0.478, P < .001) than the ratio with only major vessels to circumpapillary RNFL (r = 0.027, P = .820). Exclusion of blood vessels from circumpapillary RNFL thickness using OCTA imaging provides a better measure of the neuronal components and could potentially improve the diagnostic performance for disease detection.

Towards 'automated gonioscopy': a deep learning algorithm for 360° angle assessment by swept-source optical coherence tomography

AIMS

To validate a deep learning (DL) algorithm (DLA) for 360° angle assessment on swept-source optical coherence tomography (SS-OCT) (CASIA SS-1000, Tomey Corporation, Nagoya, Japan).

METHODS

This was a reliability analysis from a cross-sectional study. An independent test set of 39 936 SS-OCT scans from 312 phakic subjects (128 SS-OCT meridional scans per eye) was analysed. Participants above 50 years with no previous history of intraocular surgery were consecutively recruited from glaucoma clinics. Indentation gonioscopy and dark room SS-OCT were performed. Gonioscopic angle closure was defined as non-visibility of the posterior trabecular meshwork in ≥180° of the angle. For each subject, all images were analysed by a DL-based network based on the VGG-16 architecture, for gonioscopic angle-closure detection. Area under receiver operating characteristic curves (AUCs) and other diagnostic performance indicators were calculated for the DLA (index test) against gonioscopy (reference standard).

RESULTS

Approximately 80% of the participants were Chinese, and more than half were women (57.4%). The prevalence of gonioscopic angle closure in this hospital-based sample was 20.2%. After analysing a total of 39 936 SS-OCT scans, the AUC of the DLA was 0.85 (95% CI:0.80 to 0.90, with sensitivity of 83% and a specificity of 87%) to classify gonioscopic angle closure with the optimal cut-off value of >35% of circumferential angle closure.

CONCLUSIONS

The DLA exhibited good diagnostic performance for detection of gonioscopic angle closure on 360° SS-OCT scans in a glaucoma clinic setting. Such an algorithm, independent of the identification of the scleral spur, may be the foundation for a non-contact, fast and reproducible 'automated gonioscopy' in future.

New digital models of care in ophthalmology, during and beyond the COVID-19 pandemic

COVID-19 has led to massive disruptions in societal, economic and healthcare systems globally. While COVID-19 has sparked a surge and expansion of new digital business models in different industries, healthcare has been slower to adapt to digital solutions. The majority of ophthalmology clinical practices are still operating through a traditional model of ‘brick-and-mortar’ facilities and ‘face-to-face’ patient–physician interaction. In the current climate of COVID-19, there is a need to fuel implementation of digital health models for ophthalmology. In this article, we highlight the current limitations in traditional clinical models as we confront COVID-19, review the current lack of digital initiatives in ophthalmology sphere despite the presence of COVID-19, propose new digital models of care for ophthalmology and discuss potential barriers that need to be considered for sustainable transformation to take place.

Association of Rare CYP39A1 Variants With Exfoliation Syndrome Involving the Anterior Chamber of the Eye

IMPORTANCE

Exfoliation syndrome is a systemic disorder characterized by progressive accumulation of abnormal fibrillar protein aggregates manifesting clinically in the anterior chamber of the eye. This disorder is the most commonly known cause of glaucoma and a major cause of irreversible blindness.

OBJECTIVE

To determine if exfoliation syndrome is associated with rare, protein-changing variants predicted to impair protein function.

DESIGN, SETTING, AND PARTICIPANTS

A 2-stage, case-control, whole-exome sequencing association study with a discovery cohort and 2 independently ascertained validation cohorts. Study participants from 14 countries were enrolled between February 1999 and December 2019. The date of last clinical follow-up was December 2019. Affected individuals had exfoliation material on anterior segment structures of at least 1 eye as visualized by slit lamp examination. Unaffected individuals had no signs of exfoliation syndrome.

EXPOSURES

Rare, coding-sequence genetic variants predicted to be damaging by bioinformatic algorithms trained to recognize alterations that impair protein function.

MAIN OUTCOMES AND MEASURES

The primary outcome was the presence of exfoliation syndrome. Exome-wide significance for detected variants was defined as P < 2.5 × 10-6. The secondary outcomes included biochemical enzymatic assays and gene expression analyses.

RESULTS

The discovery cohort included 4028 participants with exfoliation syndrome (median age, 78 years [interquartile range, 73-83 years]; 2377 [59.0%] women) and 5638 participants without exfoliation syndrome (median age, 72 years [interquartile range, 65-78 years]; 3159 [56.0%] women). In the discovery cohort, persons with exfoliation syndrome, compared with those without exfoliation syndrome, were significantly more likely to carry damaging CYP39A1 variants (1.3% vs 0.30%, respectively; odds ratio, 3.55 [95% CI, 2.07-6.10]; P = 6.1 × 10-7). This outcome was validated in 2 independent cohorts. The first validation cohort included 2337 individuals with exfoliation syndrome (median age, 74 years; 1132 women; n = 1934 with demographic data) and 2813 individuals without exfoliation syndrome (median age, 72 years; 1287 women; n = 2421 with demographic data). The second validation cohort included 1663 individuals with exfoliation syndrome (median age, 75 years; 587 women; n = 1064 with demographic data) and 3962 individuals without exfoliation syndrome (median age, 74 years; 951 women; n = 1555 with demographic data). Of the individuals from both validation cohorts, 5.2% with exfoliation syndrome carried CYP39A1 damaging alleles vs 3.1% without exfoliation syndrome (odds ratio, 1.82 [95% CI, 1.47-2.26]; P < .001). Biochemical assays classified 34 of 42 damaging CYP39A1 alleles as functionally deficient (median reduction in enzymatic activity compared with wild-type CYP39A1, 94.4% [interquartile range, 78.7%-98.2%] for the 34 deficient variants). CYP39A1 transcript expression was 47% lower (95% CI, 30%-64% lower; P < .001) in ciliary body tissues from individuals with exfoliation syndrome compared with individuals without exfoliation syndrome.

CONCLUSIONS AND RELEVANCE

In this whole-exome sequencing case-control study, presence of exfoliation syndrome was significantly associated with carriage of functionally deficient CYP39A1 sequence variants. Further research is needed to understand the clinical implications of these findings.

Altered Iris Aquaporin Expression and Aqueous Humor Osmolality in Glaucoma

Purpose

Aquaporins (AQPs) facilitate transmembrane osmotic water transport and may play a role in iris fluid conductivity, which is implicated in the pathophysiology of glaucoma. In this study, we compared the iris expression of AQPs and aqueous osmolality between primary angle closure glaucoma (PACG), primary open-angle glaucoma (POAG), and nonglaucoma eyes.

Methods

AQP1-5 transcripts from a cohort of 36 PACG, 34 POAG and 26 nonglaucoma irises were measured by quantitative real-time PCR. Osmolality of aqueous humor from another cohort of 49 PACG, 50 POAG, and 50 nonglaucoma eyes were measured using an osmometer. The localization of AQP1 in both glaucoma and nonglaucoma irises was determined by immunofluorescent analysis.

Results

Of the five AQP genes evaluated, AQP1 and AQP2 transcripts were significantly upregulated in both PACG (3.48- and 8.07-fold, respectively) and POAG (3.12- and 11.58-fold, respectively) irises relative to nonglaucoma counterparts. The aqueous osmolalities of PACG (303.68 mmol/kg) and POAG (300.79 mmol/kg) eyes were significantly lower compared to nonglaucoma eyes (312.6 mmol/kg). There was no significant difference in expression of AQP transcripts or aqueous osmolality between PACG and POAG eyes.

Conclusions

PACG and POAG eyes featured significant increase in AQP1 and AQP2 expression in the iris and reduced aqueous osmolality compared to nonglaucoma eyes. These findings suggest that the iris may be involved in altered aqueous humor dynamics in glaucoma pathophysiology. Because PACG did not differ from POAG in both properties studied, it is likely that they are common to glaucoma disease in general.

Focal Structure-Function Relationships in Primary Open-Angle Glaucoma Using OCT and OCT-A Measurements

Purpose

To evaluate the focal structure-function associations among visual field (VF) loss, optical coherence tomography angiography (OCT-A) vascular measurements, and optical coherence tomography (OCT) structural measurements in glaucoma.

Methods

In this cross-sectional study, subjects underwent standard automated perimetry, OCT-based nerve fiber thickness measurements, and OCT-A imaging. Mappings of focal VF test locations with OCT and OCT-A measurements were defined using anatomically adjusted nerve fiber trajectories and were studied using multivariate mixed-effects analysis. Segmented regression analysis was used to determine the presence of breakpoints in the structure-function associations.

Results

The study included 119 eyes from 86 Chinese subjects with primary open-angle glaucoma (POAG). VF mean deviation was significantly associated with global capillary perfusion density (β = 0.13 ± 0.08) and global retinal nerve fiber layer thickness (β = 0.09 ± 0.02). Focal capillary density (FCD) was significantly associated with VF losses at 34 VF test locations (66.7% of 24-2 VF), with 24 of the 34 locations being within 20° of retinal eccentricity. Focal nerve layer (FNL) thickness was significantly associated with 16 VF test locations (31.4% of 24-2 VF; eight locations within 20° eccentricity). For VF test locations in the central 10° VF, VF losses below the breakpoint were significantly associated with FCD (slope, 0.89 ± 0.12, P < 0.001), but not with FNL thickness (slope, 0.57 ± 0.39, P = 0.15).

Conclusions

Focal capillary densities were significantly associated with a wider range of visual field losses and in a larger proportion of the visual field compared to nerve fiber thickness.

Automated circumpapillary retinal nerve fiber layer segmentation in high-resolution swept-source OCT

Glaucoma is a progressive optic neuropathy that leads to loss of retinal ganglion cells and thinning of retinal nerve fiber layer (RNFL). Circumpapillary RNFL thickness measurements have been used for glaucoma diagnostic and monitoring purposes. However, manual measurement of the RNFL thickness is tedious and subjective. We proposed and evaluated the performance of automated RNFL segmentation from OCT images using a state-of-the-art deep learning-based model. Circumpapillary OCT scans were extracted from volumetric OCT scans using a high-resolution swept-source OCT device. Manual annotation was performed on the extracted scans and used for training and evaluation. The results show that the accuracy and diagnostic performance is comparable to manual assessment, and the potential application of deep learning-based approach in such segmentation.

Evaluation of Refractive Status and Ocular Biometric Parameters in Primary Angle Closure Disease

INTRODUCTION

The aim of the study was to evaluate the refractive status and ocular biometric parameters in subjects with angle closure in Malaysia.

METHODS

This cross-sectional study was conducted on 171 primary angle closure patients (268 eyes). Visual acuity, refraction, and ocular biometry (central anterior chamber depth [ACD], axial length [AL], and lens thickness) were recorded. Vitreous cavity length (VL) and relative lens position (RLP) were calculated.

RESULTS

A total of 92 Primary Angle Closure Suspect (PACS), 30 Primary Angle Closure (PAC), and 146 Primary Angle Closure Glaucoma (PACG) eyes were included. Chinese ethnicity formed the majority (n = 197, 73.5%), followed by Malay (n = 57, 21.3%) and Indian (n = 14, 5.2%). There was a significant female preponderance with a female to male ratio of 1.85. Mean age was 65.7 ± 7.7 years. Mean spherical equivalent was +0.33 ± 1.29 D. Approximately half (n = 137, 51%) of the eyes were hyperopic (spherical power ≥+0.5), with PACG having the highest percentage of hyperopia (n = 69, 50.4%). Myopia and emmetropia were present in 48 (17.9) and 83 (31%) eyes, respectively. Although AL and VL in myopia patients were significantly longer than emmetropic and hyperopic eyes (p < 0.001), the ACD was not significantly different (p = 0.427). While the RLP is smaller in myopic eyes, lens thickness was increased in hyperopic eyes. PACG was significantly higher in elderly patients compared to PACS and PAC (p = 0.005). A total of 37 (13.8%) eyes were blind (vision worse than 3/60) and 19 of them (51.3%) were female patients.

CONCLUSION

A decrease in RLP is predictive of angle closure disease in myopic eyes, whereas increased lens thickness contributes to angle closure disease in hyperopic eyes.

Visual field progression 8 years after trabeculectomy in Asian eyes: results from The Singapore 5-Fluorouracil Study

BACKGROUND/AIMS

This work aimed to study the effect of long-term intraocular pressure (IOP) fluctuation on visual field (VF) progression 8 years post-trabeculectomy in Asian eyes.

METHODS

This was a retrospective analysis of 8-year post-trabeculectomy data from The Singapore 5-Fluorouracil (5-FU) Study. VFs were analysed using Progressor software (Medisoft, Leeds, UK). Outcome measures included mean slope for VF per year, number of progressing points and mean slope for progressing points per year. Multivariate regression analyses were performed adjusting for age, gender, ethnicity, glaucoma type, intraoperative 5-FU, diabetes mellitus, hypertension, best pre-trabeculectomy VF mean deviation, post-trabeculectomy mean IOP, IOP reduction and IOP fluctuation (SD of IOPs at 6-monthly timepoints).

RESULTS

127 (52.3%) subjects completed 8-year follow-up with ≥5 reliable VFs and ≥8 6-monthly IOP measurements. Mean age was 61.8±9.6 years. Post-operatively, mean IOP was 14.2±2.8 mm Hg and mean IOP fluctuation was 2.53±1.20 mm Hg. Higher IOP fluctuation was associated with greater mean slope for field (B=-0.071; p=0.013), number of progressing points (B=0.963; p=0.014) and VF progression as defined by ≥1 progressing point (OR=1.585; p=0.029). There was also a trend towards eyes with higher IOP fluctuation having ≥3 adjacent progressing points in the same hemifield (OR=1.489; p=0.055). Greater mean IOP reduction post-trabeculectomy was associated only with a lower mean slope for progressing points per year (B=-0.026; p=0.028). There was no significant effect of intra-operative 5-FU compared with placebo for all outcome measures.

CONCLUSION

In post-trabeculectomy Asian eyes with well-controlled IOP, higher long-term IOP fluctuation may be associated with greater VF progression.

Recent advances in anterior chamber angle imaging

Differentiating the two main forms of primary glaucoma (open-angle and closed-angle glaucoma) depends on the correct assessment of the anterior chamber angle (ACA). This assessment will determine the management plan and prognosis for the disease. The standard method of examining the angle has been, for many years, slit-lamp gonioscopy. This method, although clinically still useful, is less robust for patient follow up and clinical research, given its low reproducibility. Several imaging technologies have been developed in recent years to improve the evaluation of the ACA and overcome the shortcomings of gonioscopy. These recent advances include three-dimensional and 360° analysis by Swept-Source OCT (SS-OCT, CASIA, Tomey, Nagoya, Japan), the introduction of deep learning algorithms for automatic imaging classification and new goniophotographic systems. SS-OCT allows for the first time the assessment of the circumferential extension of angle closure with moderate to good diagnostic performance compared with gonioscopy. Deep learning algorithms are showing promising results for the automation of imaging analysis, and may potentially save physicians' time in regards of the interpretation of the images. Lastly, goniophotograph systems have the distinct advantage of recordability of gonioscopic findings and are most closely matched to the findings of slit-lamp gonioscopy.

Comparison of a commercial spectral-domain OCT and swept-source OCT based on an angiography scan for measuring circumpapillary retinal nerve fibre layer thickness

Background/aims

To assess the agreement in measuring retinal nerve fibre layer (RNFL) thickness between spectral-domain (SD; Cirrus HD, Carl Zeiss Meditec, USA) optical coherence tomography (OCT) and swept-source (SS; Plex Elite 9000, Carl Zeiss Meditec) OCT using an OCT angiography (OCTA) scanning protocol.

Methods

57 participants (12 glaucomatous, 8 ocular hypertensive and 74 normal eyes) were scanned with two OCT instruments by a single experienced operator on the same day. Circumpapillary RNFL thicknesses were automatically segmented for SD-OCT and manually segmented for SS-OCTA scans. Agreement of global RNFL thickness, as well as average thickness in four quadrants was assessed using intraclass correlation coefficients (ICCs).

Results

There was excellent agreement in the inferior and superior quadrants and the global (all ICC >0.90), followed by good agreement in the temporal (ICC=0.79) and nasal (ICC=0.73) quadrants. The ICC values were similar in the subgroups except within the ocular hypertension group, where the nasal quadrant was less agreeable (ICC=0.31). SS-OCTA-derived RNFL thickness was on average 3 µm thicker than SD-OCT, particularly in the nasal (69.7±11.5 µm vs 66.3±9.3 µm; p<0.001) and temporal (75.6±13.7 µm vs 67.9±12.3 µm; p<0.001) quadrants.

Conclusions

RNFL measurements taken with SS-OCTA have good-to-excellent agreement with SD-OCT, which suggests that the RNFL thickness can be sufficiently extracted from wide-field OCTA scans.

Efficacy of Phacoemulsification Alone vs Phacoemulsification With Goniosynechialysis in Patients With Primary Angle-Closure Disease: A Randomized Clinical Trial

Importance

The effectiveness of intraocular pressure (IOP) lowering phacoemulsification combined with goniosynechialysis (GSL) compared with phacoemulsification without GSL remains unknown.

Objective

To compare the IOP outcome after 1 year in patients with synechial primary angle-closure disease (PACD) and cataract who underwent phacoemulsification with intraocular lens implantation (PEI) alone compared with PEI with GSL (PEI-GSL).

Design, Setting, and Participants

A multicenter randomized clinical trial was conducted from September 29, 2011, to March 16, 2015; data analysis was performed from April 1, 2015, to March 4, 2019. Patients with PACD, defined as primary angle closure or primary angle-closure glaucoma, and at least 90° peripheral anterior synechiae (PAS) with cataract were included. Patients were randomized to undergo PEI alone or PEI-GSL. Patients were followed up for 1 year with standardized evaluations. Intention-to-treat analysis was performed.

Interventions

Phacoemulsification with intraocular lens implantation alone or with GSL.

Main Outcomes and Measures

Successful control of IOP at 12 months, defined as IOP 21 mm Hg or lower without use of topical IOP-lowering medications and a decrease in IOP of 20% or more from baseline IOP.

Results

Data from 78 patients (78 eyes) were analyzed. Of these, 37 patients were Chinese (47.4%) and 54 were women (69.2%); mean (SD) age was 67.7 (8.9) years. Mean deviation (SD) at baseline was -13.5 dB (9.4 dB). Forty patients were randomized to the PEI group and 38 to the PEI-GSL group. The mean (SD) IOP at baseline was 22.3 (8.5) mm Hg for the PEI group and 22.9 (5.3) mm Hg for the PEI-GSL group. At 1 year, the mean IOP was 14.3 (5.0) mm Hg for the PEI group and 15.9 (4.5) mm Hg for the PEI-GSL group. Successful control at 1 year occurred in 21 patients (52.5%) in the PEI group and 22 patients (57.9%) in the PEI-GSL group (mean difference, 5.4%; 95% CI, -18.0% to 28.2%; P = .63). In eyes that achieved successful control, mean IOP at 1 year was 12.5 (2.7) mm Hg (range, 7.0-19.0) for the PEI group and 13.6 (2.4) mm Hg (range, 9.0-18.0) for the PEI-GSL group. The number of medications at baseline and 1 year decreased from a mean of 2.2 (0.8) to 0.5 (0.9) in the PEI group and 1.9 (0.9) to 0.6 (1.2) in the PEI-GSL group (P < .001 for each), with a mean change difference of 0.4% (95% CI, -0.02% to 0.9%; P = .06). There were 3 postoperative complications (7.5%) in the PEI group and 3 (7.9%) in the PEI-GSL group. These included IOP spike (IOP≥30 mm Hg) (n = 3), excessive anterior chamber inflammation (n = 1), and posterior capsule opacification (n = 2).

Conclusions and Relevance

This randomized clinical trial was unable to show that PEI-GSL added additional IOP lowering compared with PEI alone in patients with PACD.

Trial Registration

ClinicalTrials.gov identifier: NCT02376725.

Characteristics of the Corneal Endothelium Across the Primary Angle Closure Disease Spectrum

Purpose

To evaluate the corneal endothelial characteristics across the primary angle closure (PAC) disease spectrum amongst patients diagnosed as PAC suspects (PACS), PAC, PAC glaucoma (PACG), and previous acute PAC (APAC).

Methods

We analyzed a total of 529 subjects (51 PACS, 170 PAC, 234 PACG, and 74 with previous APAC). All subjects had undergone laser peripheral iridotomy prior to study recruitment. Corneal endothelial parameters were measured using a noncontact specular microscope and the following parameters were obtained: mean central endothelial cell density (ECD; cells/mm2), coefficient of variation (CV) in cell area, and percentage of hexagonal cells.

Results

The mean age of the subjects was 65.1 ± 8.2 years, and 55.2% were females. The mean central ECD was 2582.0 ± 472.8 cells/mm2 in PACS, 2566.0 ± 408.3 cells/mm2 in PAC, 2523.8 ± 406.8 cells/mm2 in PACG, and 2504.0 ± 558.1 cells/mm2 in APAC, with no significant differences in ECD across the subgroups (P = 0.61). The CV was lowest in PACS (34.38 ± 6.05 μm2/cell), and highest in APAC (37.61 ± 7.98 μm2/cell), but the differences were not significant (P = 0.07). Likewise, the percentage of hexagonality was not significantly different between the groups. A subgroup analysis on the eyes with previous APAC with their fellow eye also showed no significant differences in the corneal endothelial characteristics.

Conclusions

The corneal ECD and morphological characteristics such as CV and hexagonality are not significantly different across the PAC disease spectrum. This may reflect the lack of a sustained and/or dramatic IOP insult and/or an insignificant deleterious effect from medications, age, and chronicity on corneal endothelial parameters.

Evaluation of Primary Angle-Closure Glaucoma Susceptibility Loci in Patients with Early Stages of Angle-Closure Disease

PURPOSE

To investigate whether newly identified genetic loci for primary angle-closure glaucoma (PACG) are associated with early stage angle-closure disease defined as primary angle closure suspect (PACS).

DESIGN

Case-control study.

PARTICIPANTS

A total of 1397 PACS patients and 943 controls of Chinese ethnicity from Singapore and 604 PACS patients and 287 controls of Indian ethnicity.

METHODS

The 8 PACG single nucleotide polymorphisms (SNPs; rs11024102 at PLEKHA7, rs3753841 at COL11A1, rs1015213 located between PCMTD1 and ST18 son chromosome 8q, rs3816415 at EPDR1, rs1258267 at CHAT, rs736893 at GLIS3, rs7494379 at FERMT2, and rs3739821 mapping in between DPM2 and FAM102A) were genotyped by Taqman assays. The association between SNP genotypes and PACS status was measured using logistic regression. A P value of 0.006 was set to account for the testing of 8 genetic loci using a Bonferroni correction. A meta-analysis was conducted to calculate the overall P value and accompanying per-allele odds ratios for each SNP analyzed.

MAIN OUTCOME MEASURES

Association of PACG loci with PACS status.

RESULTS

The PACS patients were significantly older in both cohorts (Chinese, P < 0.001; Indian, P = 0.002), and there were also more women (P < 0.001, both Chinese and Indian cohorts). In the Chinese cohort, significant evidence of association was noted at 3 SNPs: rs1015213 [A] in PCMTD1-ST18 (odds ratio [OR], 2.36; 95% confidence interval [CI], 1.36-4.11; P = 0.002), rs3816415 [A] in EPDR1 (OR, 1.49; 95% CI, 1.19-1.85; P < 0.001), and rs3739821 [G] in DPM2-FAM102A (OR, 1.40; 95% CI, 1.18-1.65; P < 0.001). Only PCMTD1-ST-18 was replicated modestly in the Indian population (P = 0.056). Meta-analysis showed significant evidence of association for PCMTD1-ST-18 (OR, 1.55; 95% CI, 1.18-2.04; P = 0.002) and DPM2-FAM102A (OR, 1.27; 95% CI, 1.12-1.45; P = 0.0002).

CONCLUSIONS

In this study, 2 of 8 PACG-associated loci were associated significantly with PACS status, the earliest stage in the angle-closure glaucoma disease course. The association of these PACG loci with PACS status suggests that these loci may confer susceptibility to a narrow angle configuration.

Improving the rates of electronic results acknowledgement at a tertiary eye care centre

Background

Hundreds of thousands of tests are performed annually in hospitals worldwide. Safety Issues arise when abnormal results are not recognized promptly resulting in delayed treatment and increased morbidity and mortality. As a result Singapore’s largest healthcare group, Singhealth introduced an electronic result acknowledgement system. This system was adopted by the Singapore National Eye Centre (SNEC) in February 2016. Baseline measurements show that weekly numbers of unacknowledged results ranged from 193 to 617. The current standards of electronic results acknowledgement posts a significant patient safety hazard.

Methods

Root cause analysis was performed to identify contributory factors. Pareto principle was then used by the authors to identify the main contributory factors. We employed the rapid cycle improvement Plan-do-study-act (PDSA) strategy to test and evaluate implemented changes. Changes are implemented for 2 weeks and data collected prospectively. The data is analyzed the week after and the following PDSA actions are decided and instituted the following week. 3 PDSA cycles were undertaken in total.

Results

The first PDSA cycle focused on raising awareness of the problem at hand, the number of unacknowledged results drastically decreased during the 1^stweek of implementation of our PDSA from 617 to 254. The second PDSA cycle targeted the lack of knowledge of doctors involved in the electronic result acknowledgement process. There was a trend downwards near the end of the cycle which continued through the week after. The third PDSA cycle targeted individual doctors and provided individual remedial training. Second line doctors were also equipped to better handle abnormal results. There was significant improvement with the number of unacknowledged abnormal results dropping to <5 a week.

Conclusions

Multiple factors were identified to contribute to the low compliance to electronic acknowledgement of results. The role doctors play in the issue at hand was paramount and required careful handling in a professional manner with multiple reminders and emphasis on the importance of acknowledging and acting on the results.A significant improvement in the rates of acknowledgement of abnormal results was demonstrated with clear benefits to patient safety. Interventions can be replicated when implementing similar systems to other areas of healthcare.