AIM:To study the microvascular density of the macular and optic nerve head in healthy and glaucoma subjects using optical coherence tomography angiography.
METHODOLOGY:We performed a cross-sectional ...cohort study on healthy subjects and patients with glaucoma. The AngioVue Enhanced Microvascular Imaging System was used to capture the optic nerve head and macula images during one visit. En face segment images of the macular and optic disc were studied in layers. Microvascular density of the optic nerve head and macula were quantified by the number of pixels measured by a novel in-house developed software. Areas under the receiver operating characteristic curves (AUROC) were used to determine the accuracy of differentiating between glaucoma and healthy subjects.
RESULTS:A total of 24 (32 eyes) glaucoma subjects (57.5±9.5-y old) and 29 (58 eyes) age-matched controls (51.17±13.5-y old) were recruited. Optic disc and macula scans were performed showing a greater mean vessel density (VD) in healthy compared with glaucoma subjects. The control group had higher VD than the glaucoma group at the en face segmented layers of the optic disc (optic nerve head0.209±0.05 vs. 0.110±0.048, P<0.001; vitreoretinal interface0.086±0.045 vs. 0.052±0.034, P=0.001; radial peripapillary capillary0.146±0.040 vs. 0.053±0.036, P<0.001; and choroid0.228±0.074 vs. 0.165±0.062, P<0.001). Similarly, the VD at the macula was also greater in controls than glaucoma patients (superficial retina capillary plexus0.115±0.016 vs. 0.088±0.027, P<0.001; deep retina capillary plexus0.233±0.027 vs. 0.136±0.073, P<0.001; outer retinal capillary plexus0.190±0.057 vs. 0.136±0.105, P=0.036; and choriocapillaris0.225±0.053 vs. 0.153±0.068, P<0.001. The AUROC was highest for optic disc radial peripapillary capillary (0.96), followed by nerve head (0.92) and optic disc choroid (0.76). At the macula, the AUROC was highest for deep retina (0.86), followed by choroid (0.84), superficial retina (0.81), and outer retina (0.72).
CONCLUSIONS:Microvascular density of the optic disc and macula in glaucoma patients was reduced compared with healthy controls. VD of both optic disc and macula had a high diagnostic ability in differentiating healthy and glaucoma eyes.
Purpose
The Coronavirus (COVID-19) outbreak is rapidly emerging as a global health threat. With no proven vaccination or treatment, infection control measures are paramount. In this article, we aim ...to describe the impact of COVID-19 on our practice and share our strategies and guidelines to maintain a sustainable ophthalmology practice.
Methods
Tan Tock Seng Hospital (TTSH) Eye Centre is the only ophthalmology department supporting the National Centre for Infectious Diseases (NCID), which is the national screening center and the main center for management of COVID-19 patients in Singapore. Our guidelines during this outbreak are discussed.
Results
Challenges in different care settings in our ophthalmology practice have been identified and analyzed with practical solutions and guidelines implemented in anticipation of these challenges. First, to minimize cross-infection of COVID-19, stringent infection control measures were set up. These include personal protective equipment (PPE) for healthcare workers and routine cleaning of “high-touch” surfaces. Second, for outpatient care, a stringent dual screening and triaging process were carried out to identify high-risk patients, with proper isolation for such patients. Administrative measures to lower patient attendance and reschedule appointments were carried out. Third, inpatient and outpatient care were separated to minimize interactions. Last but not least, logistics and manpower plans were drawn up in anticipation of resource demands and measures to improve the mental well-being of staff were implemented.
Conclusion
We hope our measures during this COVID-19 pandemic can help ophthalmologists globally and serve to guide and maintain safe access in ophthalmology clinics when faced with similar disease outbreaks.
Primary open angle glaucoma (POAG) is a complex disease and a leading cause of irreversible blindness, and its underlying pathophysiology remains poorly understood. Proteomic characterization of the ...protein composition of aqueous humor (AH) may identify prognostic candidate proteins involved in pathogenesis and progression of the disease. To delineate the possible mechanisms that lead to POAG, this study adopted state-of-art mass spectrometric technique and analyzed AH of POAG and their respective controls. In total, more than 1000 proteins were identified with false discovery rate of less than 1%. Numerous proteins of complement cascade, immunoglobulin, neuronal and amyloidogenic proteins, which were part of processes like acute-phase and inflammatory response, humoral immune and acute inflammatory response, regulation of complement activation and protein processing were identified. Proteins of complement system underwent significant changes, which correlate to pathogenic events characterizing POAG, including altered complement cascade, astrocyte activation, neural degeneration, and apoptosis. Further, protein modification such as deamidation of complement subcomponent was noted, particularly in POAG. Proteomic analysis of AH allows a better understanding of the mechanism involved in the pathogenesis of POAG.
To conduct a preliminary evaluation of the feasibility of visual field fast (VFF), a free iPad-based noise-field perimeter, in detecting glaucomatous scotomas versus the clinical-standard Humphrey ...visual field (HVF) test. VFF confronts subjects with a screen of flickering stimulus, allowing the immediate perception of scotomas.
This was a cross-sectional observational study of 66 glaucoma patients (66 eyes) and 30 healthy controls (30 eyes). All patients had no other visual field disorders. VFF was compared against HVF in terms of whole field and quadrants for the following: (1) correspondence in scotoma detection. (2) Agreement and correlation of the scotoma size (percentage of abnormal visual field area). (3) Test duration. Other domains tested included: (1) correlation of VFF scotoma area with the severity of visual field loss on HVF (mean deviation, MD; visual field index, VFI). (2) Repeatability of VFF. (3) Patient descriptors of scotomas.
Using HVF pattern deviation plot as a reference, VFF detected 52/57 (91.2%) of glaucoma subjects with 1 false-positive (control) (kappa = 0.86). 146/184 (79.3%) of abnormal quadrants (visual field defect present) were localized and 23/157 (14.6%) healthy quadrants were falsely identified as abnormal (kappa = 0.61). VFF underestimated scotoma area as compared to HVF (21.0% versus 44.0%, p < 0.01) but correlated positively (r = 0.268, p = 0.044) with HVF area and negatively with VFI (r = -0.340, p = 0.01) and MD (r = -0.398, p < 0.01). Using HVF total deviation plot as reference, VFF's glaucoma detection rate remained unchanged (kappa = 0.86) with similar quadrant detection (kappa = 0.68). However, a greater underestimation of scotoma area was observed (21.0% versus 85.4%, p < 0.01). VFF's quantitative repeatability was excellent for whole field (intraclass correlation coefficient, ICC: 0.96; p < 0.0001) and quadrants (ICC: 0.82-0.96; all p < 0.001). Qualitatively, 35/37 (94.6%) of subjects reported reduced luminance and flicker in scotomas, with similar morphologies on retests. VFF is faster than HVF SITA-Standard in glaucoma (3.60 ± 1.85 min versus 6.92 ± 1.12 min, p < 0.01) and control (1.12 ± 0.486 min versus 5.16 ± 0.727 min, p < 0.01).
This early model of VFF accurately detected scotomas with high repeatability. However, its accuracy in localizing and quantifying the scotoma can be improved. Considering its portability and cost-effectiveness, VFF demonstrated potential as a general screening tool for moderate-to-severe glaucoma.
The iCare HOME tonometer is a useful tool which can be used by patients for fairly accurate and reliable self-measurement of intraocular pressure (IOP).
The aim was to compare the accuracy of IOP ...measurements of trained glaucoma patients using the iCare HOME tonometer before and after a week of self-monitoring at home and study the repeatability of patient measurements done at home.
A total of 40 glaucoma patients had IOPs measured using the Goldmann applanation tonometer and the iCare HOME. Patients were trained to use the iCare HOME and measured their IOP twice daily over a loan period of 7 days. Bland-Altman analysis was used to assess agreement between Goldmann applanation tonometer and iCare HOME readings. Intraclass correlation coefficient compared inter-rater reliability of iCare HOME measurements, and test-retest variability for the patient's readings over the 7-day period were analyzed. A 5-point Likert scale questionnaire was used to assess the patient's experience with the device.
Up to 32 patients (80%) were able to obtain IOP readings within 3 mm Hg of the glaucoma nurse clinician's readings at the preloan visit, and up to 36 patients (90%) at the postloan visit. Good inter-rater reliability was observed between iCare HOME measurements by the glaucoma nurse clinician and patients. At the postloan visit, inter-rater reliability was good for right eye readings and excellent for left eye readings. No distinct trend in test-retest variability was identified over the 7-day period. 65% of patients agreed the device was easy to use and 89% would recommend the device to other glaucoma patients.
Patients trained to use the iCare HOME device can do so with fair accuracy compared with trainers with accuracy improving within 1 week of usage.
Purpose
To evaluate efficacy and safety of the iStent inject combined with phacoemulsification in Asian eyes with normal-tension glaucoma (NTG) up to 12 months after surgery.
Study design
...Retrospective case series.
Methods
Retrospective case series of eyes undergoing surgery from April 2017 to August 2019. Outcome measures included intraocular pressure (IOP), number of topical glaucoma medications and adverse outcomes. Data were retrieved from the post-operative day 1 (POD1), week 1 (POW1), month 1 (POM1), month 3 (POM3), month 6 (POM6) and month 12 (POM12) timepoints. Data were analysed at each timepoint for eyes with available clinical data at that visit. Subgroup analysis was performed for a consistent cohort which included only eyes with data at all six follow-up timepoints.
Results
Data from 91 eyes in the collective subject group was analysed. Majority of subjects were male (53, 58.2%) and Chinese (79, 86.8%). Mean age was 73.2 ± 7.2 years. Pre-operatively, mean IOP was 14.3 ± 3.0 mmHg and mean number of medications was 1.5 ± 0.8. Significant IOP reduction was observed at all timepoints except POW1 and POM12. The number of medications was reduced at all timepoints (
p
< 0.001). By POM12, there was reduction of 1.2 ± 1.0 medications (
p
< 0.001). Both the collective and consistent cohorts demonstrated a trend towards decreasing surgical efficacy with time, in IOP reduction and decrease in medications. None of the eyes experienced sight-threatening complications.
Conclusions
Asian eyes with NTG undergoing combined phacoemulsification and iStent inject surgery demonstrated significant and sustained reduction in number of glaucoma medications up to 12 months post-operatively.
PURPOSE:To determine the prevalence and risk factors for anxiety disorder and depression among glaucoma patients in Singapore, and to assess the relationship between quality of life (QOL) and ...depression/anxiety.
METHODS:In this cross-sectional study, glaucoma patients aged 21 and above with a known diagnosis of primary open-angle glaucoma or primary angle-closure glaucoma were recruited from a tertiary care hospital. Patients with other types of glaucoma, and coexisting ocular or psychiatric disorders were excluded.Ophthalmic examination was carried out on all participants, which included best-corrected visual acuity (BCVA), intraocular pressure (IOP), gonioscopy, standard automated perimetry, and optic disc evaluation. Sociodemographic information and treatment histories were also collected.The Hamilton Depression Rating Scale (HAM-D), Hamilton Anxiety Rating Scale (HAM-A), and Visual Function Questionnaire (VFQ25) were administered to evaluate for depression, anxiety, and impact on QOL, respectively.
RESULTS:A total of 100 patients were included in this study. The mean age was 67.1±12.0 years (range, 24 to 90 y). The frequency of depression and anxiety among our patients was 30% and 64%, respectively. The mean HAM-D score was 4.37±4.17 (range, 0 to 17), whereas the mean HAM-A score was 2.38±2.80 (range, 0 to 13). The mean VFQ25 score was 78.8±16.0 (range, 42.4 to 97.0). The poorest subscale on the VFQ25 was driving, with a mean score of 42.4±42.6 (range, 0.0 to 100.0).We did not find any significant difference between the presence of depression/anxiety between patients with primary open-angle glaucoma (P=0.263) and primary angle-closure glaucoma (P=0.830). Risk factors for depression includedfemale sex (P=0.020), higher logMAR BCVA in the worse eye (P=0.004), higher cup-disc ratio (P=0.016), lower MD in the better and worse eye (P=0.022 and 0.001, respectively), and lower mean VFQ25 score (P<0.001). Risk factors for anxiety includedlower MD in the worse eye (P=0.004) and lower mean VFQ25 score (P=0.004). There was also no significant association between the use of topical β-blockers/carbonic anhydrase inhibitors with depression (P=0.793) or anxiety (P=0.282).
CONCLUSIONS:There is a relatively high prevalence of depression (30%) and anxiety disorders (64%) among glaucoma patients in Singapore. Female glaucoma patients are more likely to suffer from depression. Other risk factors for depression include higher cup-disc ratio, higher logMAR BCVA, lower MD, and a lower mean VFQ25 score. Risk factors for anxiety disorder include lower MD and lower mean VFQ25 score. Ophthalmologists could consider use of the VFQ25 as an assessment for impairments in QOL in a glaucoma patient. If a glaucoma patient is at high risk of depression or anxiety disorder, a multidisciplinary management approach involving ophthalmology and psychiatry may be required.
The XEN45 gel stent implant (Allergen, CA, USA) is one of many micro-invasive surgical options available to glaucomatologists. Our case series describes the presentation, treatment, and possible risk ...factors of XEN45 gel stent related endophthalmitis.
A 71 year old Chinese man and a 88 year old Caucasian woman underwent XEN45 gel stent implantation for primary open angle glaucoma. They presented with endophthalmitis at 7 and 4 months post-surgery respectively. The first patient had stent exposure with blebitis while the second patient did not show any signs of conjunctival defect, stent exposure, bleb leak nor blebitis. Both patients were treated immediately with intravitreal, topical and systemic antibiotics, followed by early vitrectomy. The implant was removed in the first, but not in the second patient. Vitreous cultures grew Streptococcus Viridans in the first patient and Haemophilus influenzae in the other. Unfortunately, the first patient eventually sustained a total retinal detachment requiring surgery and did not recover his vision. The second patient however, recovered with a good Snellen's visual acuity of 6/9 and maintenance of good intraocular pressure and bleb formation.
Exogenous endophthalmitis related to XEN45 gel stent implantation is a rare but devastating complication. The risks factors identified were multiple post-operative procedures, bleb exposure, conjunctival defect, use of antifibrotics, blepharitis and prolonged post-operative antibiotics. XEN45 gel stent implant provides a different challenge to ophthalmologists compared to trabeculectomy as more post-operative procedures are required to prevent subconjunctival scarring. Great care should be taken to individualize the use of antifibrotics in each patient to balance the risk of subconjunctival fibrosis with the risk of infection. In patients with stent exposure we propose early closure of the conjunctiva to close off the portal of entry for pathogens and reduce the need for prophylactic topical antibiotics.
PURPOSETo determine the repeatability of retinal nerve fiber layer (RNFL) measurement from 2 spectral domain optical coherence tomography (OCT) instruments and assess the level of agreement. A ...secondary objective was to assess if pupillary dilatation affected the repeatability of RNFL measurement.
DESIGNProspective, observational study.
PARTICIPANTSFifty normal participants were recruited after being screened for exclusion criteria, which included preexisting glaucoma and significant cataract.
METHODSPeripapillary RNFL thickness was measured from either eye of the 50 participants using both the Cirrus and Spectralis OCTs. Three scans were performed consecutively for each instrument and the process was repeated after pupillary dilatation.
MAIN OUTCOME MEASURESTest-retest variability, coefficient of variation, and intraclass correlation coefficient (ICC) for repeatability of RNFL measurement. ICC and Bland-Altman plots for agreement between both devices.
RESULTSTest-retest variability for the Cirrus and Spectralis OCTs were 4.89 μm and 4.95 μm, respectively. RNFL measurements were less repeatable in the 4 quadrants, ranging from 5.02 to 15.00 μm. The temporal quadrant was the most repeatable quadrant for the Cirrus OCT with a variability of 7.81 μm, whereas the nasal quadrant was the most repeatable for Spectralis OCT with 5.02 μm. Test-retest variability was poorer for the Cirrus OCT in the nasal, inferior, and superior quadrants. Pupillary dilatation increased repeatability of RNFL measurement for Cirrus OCT, particularly in the superior quadrant, whereas not affecting measurements from Spectralis OCT. ICC values for agreement between both instruments were good. For average RNFL as well as RNFL in the superior, inferior, and temporal quadrants, ICC ranged from 0.859 to 0.908. The nasal quadrant had a lower ICC of 0.663. Bland-Altman plots showed that the Spectralis OCT provided the thicker RNFL measurement in general, except in the nasal quadrant when RNFL was thin.
CONCLUSIONSThe repeatability of RNFL thickness measurement in normal participants was excellent for both the Cirrus and Spectralis OCTs. Agreement of RNFL measurement between both the devices was generally good, with the exception of the nasal quadrant in which a linear relationship exists. Pupillary dilatation improved the repeatability of RNFL measurement for Cirrus while having minimal influence on Spectralis OCT. More studies will be required to ascertain the relationships of RNFL measurement between the different spectral domain OCT instruments in normal and glaucomatous patients.
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