The Effectiveness of a Nurse-led Glaucoma Education on Patient Knowledge and Compliance Motivation Levels: A 1-year Prospective Case Series.

Purpose: To evaluate the impact of a nurse-led glaucoma education program on patient knowledge and compliance levels in an Asian population. Materials and Methods: A 1-year prospective case series involving 69 adult glaucoma patients. Each patient attended a standardized nurse-led glaucoma education session. A questionnaire was administered by a single nurse-clinician and analyzed at three time points (preeducation for baseline, immediately posteducation, and at the 1-year follow-up) to evaluate for associations with patient knowledge and compliance motivation levels. Results: A total of 64 patients were included in the final analysis. Patients with higher educational qualifications or who were employed had better baseline knowledge of glaucoma. Younger patients had higher baseline compliance motivation levels. Immediately posteducation, both median patient knowledge score and compliance motivation levels had a statistically significant increase. Patients on more glaucoma eye drops had greater immediate improvement in confidence in eye drop application. Patients with more positive Humphrey visual field mean deviation values had a greater immediate improvement in confidence in their understanding of glaucoma. A total of 34 patients were readministered the questionnaire at the 1-year time point. Median score for patient knowledge was highest at this point. Employed patients demonstrated better patient knowledge at baseline and at 1-year time point compared to unemployed patients. Unemployed patients experienced a significant improvement in scores from baseline to immediately posteducation, but improvement from immediately posteducation to the 1-year time point was insignificant was insignificant. Conclusion: Our study has examined the effectiveness of a nurse-led glaucoma education program in an Asian population, demonstrating improvement in both patient knowledge and compliance motivation levels up to 1 year after intervention. How to cite this article: Sng JJ, Ang BCH, Soo Hoo WC, et al. The Effectiveness of a Nurse-led Glaucoma Education on Patient Knowledge and Compliance Motivation Levels: A 1-year Prospective Case Series. J Curr Glaucoma Pract 2023;17(3):149-156.

"Culture-positive exogenous endophthalmitis related to XEN45 gel stent implantation".

PURPOSE: 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. OBSERVATIONS: 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. CONCLUSIONS: 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.

12-Month Outcomes of Combined Phacoemulsification and iStent Inject in Asian Eyes with Normal Tension Glaucoma: A Single-Centre Experience.

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.

The performance of iPad-based noise-field perimeter versus Humphrey Field Analyser in detecting glaucomatous visual field loss.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Accuracy and Reliability of Self-measured Intraocular Pressure in Glaucoma Patients Using the iCare HOME Tonometer.

PRCIS: 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). PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Automatic Glaucoma Detection from Stereo Fundus Images.

This paper proposes a new method for automatic detection of glaucoma from stereo pair of fundus images. The basis for detecting glaucoma is using the optic cup-to-disc area ratio, where the surface area of the optic cup is segmented from the disparity map estimated from the stereo fundus image pair. More specifically, we first estimate the disparity map from the stereo image pair. Then, the optic disc is segmented from one of the stereo image. Based upon the location of the optic disc, we perform an active contour segmentation on the disparity map to segment the optic cup. Thereafter, we can compute the optic cup-to-disc area ratio by dividing the area (i.e. the total number of pixels) of the segmented optic cup region to that of the segmented optic disc region. Our experimental results using the available test dataset shows the efficacy of our proposed approach.

Sustainable practice of ophthalmology during COVID-19: challenges and solutions.

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.

Efficacy of the XEN gel stent on intraocular pressure lowering in East Asian eyes.

PURPOSE: This study aims to evaluate the efficacy and safety of XEN45 gel stent (Allergan plc, Dublin, Ireland) in East Asian patients with glaucoma. METHODS: A retrospective study of consecutive XEN45 gel stent implantation surgeries with or without concurrent cataract surgery from May 2017 to August 2018 was performed in a single institution. The clinical charts of all cases were reviewed to examine the safety and efficacy of the implant. Primary outcome measures were intraocular pressure (IOP), number of topical glaucoma medications required, additional procedures done and adverse outcomes. All patients included were required to fulfil a minimum of three follow-up visits by post-operative month 1. RESULTS: Sixty-three eyes were included in the study. The median duration of follow-up was 6 months [interquartile range (IQR) 2-9]. Median IOP was significantly lowered from 19 mmHg (IQR 16-24) pre-operatively to 15 mmHg (IQR 11-18) at the end-of-follow-up (p < 0.001). The median number of medications was reduced from 3 (IQR 2-4) at baseline to 0 (IQR 0-2) at the end-of-follow-up (p < 0.001). 66.7% of patients were medication-free by the end of follow-up. Post-operative bleb intervention was required for 61.9% of eyes. Adverse events included post-operative hypotony requiring intervention (4.8%) and post-operative gross hyphaema (9.6%). CONCLUSION: The XEN45 gel stent when used as a sole procedure or in combination with cataract surgery in East Asian eyes is effective in the treatment of glaucoma. However, a high rate of post-operative bleb intervention appears to be required to support its efficacy.

Aqueous humor protein dysregulation in primary angle-closure glaucoma.

PURPOSE: Primary angle-closure glaucoma (PACG) is associated with increased intraocular pressure, optic nerve damage, and progressive vision loss, but the molecular mechanism that underpins retinal ganglion neuropathy in PACG remains poorly understood. To better understand the pathogenesis of human PACG, we performed the first comprehensive proteomic analysis of aqueous humor (AH) samples from PACG patients and matched control donors to study pathogenic alteration in AH composition in disease. METHODS: High-resolution, label-free, liquid chromatography-tandem mass spectrometry-based quantitative proteomic analyses were performed in AH samples collected from PACG patients and a matched control cohort of patients with cataracts. RESULTS: The AH proteome comprised of 1363 distinct proteins, of which more than 50% were differentially expressed in PACG (773 total; 501 up-regulated, 272 down-regulated). AH from PACG patients was enriched in atypical collagens and fibronectins, suggesting that the composition of the trabecular matrix is significantly altered in disease. Pathway and cluster analyses revealed that AH protein modulation in PACG is closely associated with biological processes including platelet degranulation, cellular import/export mechanisms, and control of protease activity. In addition, critical mediators of oxygen homeostasis and neuronal function in AH were significantly dysregulated in disease, strongly implicating oxidative stress responses in PACG-associated nerve damage. CONCLUSIONS: Altered AH proteome in human PACG indicated oxidative stress in the neuronal damage that preceded vision loss. Identifying key mediators of PACG pathology will yield new prognostic biomarkers and novel targets for future therapeutic interventions.

Optical Coherence Tomography Angiography of Optic Disc and Macula Vessel Density in Glaucoma and Healthy Eyes.

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 head: 0.209±0.05 vs. 0.110±0.048, P<0.001; vitreoretinal interface: 0.086±0.045 vs. 0.052±0.034, P=0.001; radial peripapillary capillary: 0.146±0.040 vs. 0.053±0.036, P<0.001; and choroid: 0.228±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 plexus: 0.115±0.016 vs. 0.088±0.027, P<0.001; deep retina capillary plexus: 0.233±0.027 vs. 0.136±0.073, P<0.001; outer retinal capillary plexus: 0.190±0.057 vs. 0.136±0.105, P=0.036; and choriocapillaris: 0.225±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.

Proteomic Analysis of Aqueous Humor from Primary Open Angle Glaucoma Patients on Drug Treatment Revealed Altered Complement Activation Cascade.

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.

Glaucoma classification from retina optical coherence tomography angiogram.

This paper presents a new method for classification of retina into glaucoma and non-glaucoma cases based on optical coherence tomography angiogram (OCTA). The key idea here is to analyze the retinal microvasculature in the optic disc area of an enface OCTA for glaucoma classification. To facilitate this analysis, we propose a way to extract a so-called "optic disc microvasculature" region and then propose several features that will be extracted from this microvasculature region. A machine classifier is then trained using the designated features and subsequently used to classify the OCTA data. We show that our proposed approach works well on the tested dataset.

Comparison of Ethnic-specific Databases in Heidelberg Retina Tomography-3 to Discriminate Between Early Glaucoma and Normal Chinese Eyes.

PURPOSE: To compare the diagnostic accuracy of the 3 race-specific normative databases in Heidelberg Retina Tomography (HRT)-3, in differentiating between early glaucomatous and healthy normal Chinese eyes. METHOD: 52 healthy volunteers and 25 glaucoma patients were recruited for this prospective cross-sectional study. All underwent standardized interviews, ophthalmic examination, perimetry and HRT optic disc imaging. Area under the curve (AUC) receiver operating characteristics, sensitivity and specificity were derived to assess the discriminating abilities of the 3 normative databases, for both Moorfields Regression Analysis (MRA) and Glaucoma Probability Score (GPS). RESULTS: A significantly higher percentage (65%) of patients were classified as "within normal limits" using the MRA-Indian database, as compared to the MRA-Caucasian and MRA-African-American databases. However, for GPS, this was observed using the African-American database. For MRA, the highest sensitivity was obtained with both Caucasian and African-American databases (68%), while the highest specificity was from the Indian database (94%). The AUC for discrimination between glaucomatous and normal eyes by MRA-Caucasian, MRA-African-American and MRA-Indian databases were 0.77 (95% CI, 0.67-0.88), 0.79 (0.69-0.89) and 0.73 (0.63-0.84) respectively. For GPS, the highest sensitivity was obtained using either Caucasian or Indian databases (68%). The highest specificity was seen with the African-American database (98%). The AUC for GPS-Caucasian, GPS-African-American and GPS-Indian databases were 0.76 (95% CI, 0.66-0.87), 0.77 (0.67-0.87) and 0.76 (0.66-0.87) respectively. CONCLUSION: Comparison of the 3 ethnic databases did not reveal significant differences to differentiate early glaucomatous from normal Chinese eyes.

Genome-wide association study identifies five new susceptibility loci for primary angle closure glaucoma.

Primary angle closure glaucoma (PACG) is a major cause of blindness worldwide. We conducted a genome-wide association study (GWAS) followed by replication in a combined total of 10,503 PACG cases and 29,567 controls drawn from 24 countries across Asia, Australia, Europe, North America, and South America. We observed significant evidence of disease association at five new genetic loci upon meta-analysis of all patient collections. These loci are at EPDR1 rs3816415 (odds ratio (OR) = 1.24, P = 5.94 × 10(-15)), CHAT rs1258267 (OR = 1.22, P = 2.85 × 10(-16)), GLIS3 rs736893 (OR = 1.18, P = 1.43 × 10(-14)), FERMT2 rs7494379 (OR = 1.14, P = 3.43 × 10(-11)), and DPM2-FAM102A rs3739821 (OR = 1.15, P = 8.32 × 10(-12)). We also confirmed significant association at three previously described loci (P < 5 × 10(-8) for each sentinel SNP at PLEKHA7, COL11A1, and PCMTD1-ST18), providing new insights into the biology of PACG.

Assessment of Depression, Anxiety, and Quality of Life in Singaporean Patients With Glaucoma.

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 included: female 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 included: lower 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 ß-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.

Effect of Head Tilt and Ocular Compensatory Mechanisms on Retinal Nerve Fiber Layer Measurements by Cirrus Spectral Domain and Spectralis Optical Coherence Tomography in Normal Subjects.

PURPOSE: To determine the effect of head tilt and ocular compensatory mechanisms on retinal nerve fiber layer (RNFL) thickness measurements using the Cirrus and Spectralis spectral-domain optical coherence tomography (OCT) in healthy eyes. Our secondary objective was to assess the visual influence on ocular compensatory mechanisms during head tilt. MATERIALS AND METHODS: This is a prospective, observational study. A single randomly selected eye was scanned undilated in 3 positions (baseline, right, and left tilt) using both machines. In addition, patching was also done for the contralateral eye during head tilt and RNFL measurements repeated. The paired t test was used to analyze effect on RNFL thickness. One-way repeated-measures analysis of variance was used to compare differences in RNFL measurements. RESULTS: In Cirrus OCT RNFL analysis, ipsilateral head tilt resulted in superior thinning and temporal thickening, whereas contralateral head tilt resulted in inferior thinning, nasal thickening, as well as temporal thickening (all P<0.05). Head tilt did not cause any significant change in RNFL thickness with Spectralis OCT (P>0.05). Patching the contralateral eye also did not alter Cirrus RNFL measurement errors due to head tilt. CONCLUSIONS: Head tilt can affect the measurement of the RNFL thickness in Cirrus OCT, and ocular compensatory mechanisms were not sufficient to prevent this. In contrast, Spectralis OCT RNFL thickness measurements were not affected by head tilt. Patching the contralateral eye during head tilt in Cirrus OCT also did not affect RNFL variability. The visual influence on ocular compensatory mechanisms during head tilt appears insignificant.

Comparative efficacy and tolerability of topical prostaglandin analogues for primary open-angle glaucoma and ocular hypertension.

OBJECTIVE: To systematically review the efficacy and tolerability of 4 prostaglandin analogues (PGAs) as first-line monotherapies for intraocular pressure (IOP) lowering in adult patients with primary open-angle glaucoma or ocular hypertension. DATA SOURCES: A literature search was performed in PubMed (1965-June 2013) and the Cochrane Library (1980-June 2013) using the search terms ocular hypertension, open-angle glaucoma, prostaglandin analogues, bimatoprost, latanoprost, tafluprost, and travoprost. Additional studies were searched from the reference lists of identified publications. STUDY SELECTION AND DATA EXTRACTION: In all, 32 randomized controlled trials comparing between PGAs (bimatoprost 0.03%, latanoprost 0.005%, tafluprost 0.0015%, and travoprost 0.004%) or PGA with timolol were selected. DATA SYNTHESIS: A network meta-analysis was conducted. Using timolol as reference, the relative risks (RRs) of achieving treatment success, defined as the proportion of patients achieving at least 30% IOP reduction, with 95% CIs, were as follows: bimatoprost, 1.59 (1.28-1.98); latanoprost, 1.32 (1.00-1.74); travoprost, 1.33 (1.03-1.72); and tafluprost, 1.10 (0.85-1.42). The mean IOP reductions after 1 month were 1.98 (1.50-2.47), 1.01 (0.55-1.46), 1.08 (0.59-1.57), and 0.46 (-0.41 to 1.33) mm Hg, respectively, and the results were sustained at 3 months. Bimatoprost was associated with the highest risk of developing hyperemia, whereas latanoprost had the lowest risk, with RRs (95% CI) of 4.66 (3.49-6.23) and 2.30 (1.76-3.00), respectively. CONCLUSIONS: Bimatoprost achieved the highest efficacy in terms of IOP reduction, whereas latanoprost had the most favorable tolerability profile. This review serves to guide selection of the optimal PGA agent for individual patient care in clinical practice.

Comparison of retinal nerve fiber layer measurement between 2 spectral domain OCT instruments.

PURPOSE: To 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. DESIGN: Prospective, observational study. PARTICIPANTS: Fifty normal participants were recruited after being screened for exclusion criteria, which included preexisting glaucoma and significant cataract. METHODS: Peripapillary 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 MEASURES: Test-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. RESULTS: Test-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. CONCLUSIONS: The 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.