Elizabeth Poh Ying Wong

Choroidal vascularity index – a novel optical coherence tomography parameter for disease monitoring in diabetes mellitus?

To propose the use of choroidal vascularity index (CVI) as a novel tool to assess vascular status of the choroid using image binarization of enhanced depth imaging (EDI) optical coherence tomography (OCT) scans in diabetes mellitus (DM).

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 &bgr;-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.

Telemedicine Screening for Cytomegalovirus Retinitis Using Digital Fundus Photography

BACKGROUND Screening for cytomegalovirus retinitis (CMVR) is important in patients with acquired immune deficiency syndrome and low CD4(+) counts. However, many human immunodeficiency virus (HIV) patients lack access to specialist ophthalmological care. Telemedicine screening is a cost-effective method for screening these patients. We aimed to report the use of composite nine-field digital fundus photography (DFP) images for CMVR screening. We report its sensitivity and specificity in detecting CMVR and the level of agreement with gold-standard binocular indirect ophthalmoscopy. MATERIALS AND METHODS An audit was performed on our national CMVR screening program that screened all HIV patients referred to the Ophthalmology Department at Tan Tock Seng Hospital, Singapore. All patients underwent retinal screening with DFP. Images were categorized as CMVR-positive, CMVR-negative, suspicious, or unreadable by blinded retinal specialists. Patients subsequently underwent dilated gold-standard indirect ophthalmoscopy by a different retinal specialist. Diagnoses were categorized as CMVR-positive, CMVR-negative, or unreadable. Sensitivity and specificity of retinal findings on DFP and kappa values for level of agreement between the two screening methods were calculated. RESULTS Three hundred seventy screenings on 188 patients were performed. Twenty-three eyes diagnosed with CMVR on indirect ophthalmoscopy were also identified on DFP (100% sensitivity). A 99.9% specificity was achieved. The fundus photograph of one eye without CMVR was read as CMVR-positive because of an artifact, accounting for a false-positive. Kappa values ranged from 0.739 to 0.987. CONCLUSIONS DFP is a sensitive and specific method of screening HIV patients for CMVR and has a high level of agreement with indirect ophthalmoscopy.

Trends in patterns of intermediate uveitis in a tertiary institution in Singapore.

Purpose The study aims to describe the characteristics and etiologic causes of intermediate uveitis (IU) patients seen by a tertiary eye center in Singapore over 8 years. Methods This was a retrospective analysis of the clinical records of consecutive new cases of IU that presented to the uveitis subspecialty clinic from 2004–2011 at Tan Tock Seng Hospital. Data collected included demographics, clinical and laboratory findings. Diagnoses were based on standardized clinical history, ophthalmological examination and investigations. Results There were 66 new cases of IU, comprising 5.7% of 1168 new uveitis patients. The median age of diagnosis was 40 years (mean 39.4±15.9), with largest subgroup of the patients in the age group of 41–60 years (36.4%). The majority was Chinese (57.6%), followed by Asian Indians (18.2%) and Malays (16.7%). The ethnicity distribution was dissimilar to our ethnic distribution in Singapore (p<0.001) with an increased incidence of IU in the Asian Indian population. Most were idiopathic (59.1%) in etiology, followed by tuberculosis (TB) (15.2%). Ocular complications developed in 21 patients (31.8%), with cystoid macular edema (CME) being the commonest (28.8%). Severe vitritis occurred in 9.1% of patients, and was significantly associated with TB-associated IU (p<0.001). There was a downward trend for the incidence of the proportion of IU patients over the total uveitis patients (p = 0.021), with Spearman’s rho of −0.786. Conclusions Despite the downward trend, TB-associated IU was still of higher prevalence compared to less endemic areas, emphasizing the need for increased TB surveillance. A high index of suspicion for TB-associated IU is required in patients with severe vitritis. Comparisons with other countries revealed disparities in the IU etiologies, indicating possible geographical differences. Prevalence of known immune-mediated etiologies of IU is less compared to the western population. Our study also suggests a probable predisposition of the Singapore local Indian population for IU.

Agreement of angle closure assessments between gonioscopy, anterior segment optical coherence tomography and spectral domain optical coherence tomography

AIM To determine angle closure agreements between gonioscopy and anterior segment optical coherence tomography (AS-OCT), as well as gonioscopy and spectral domain OCT (SD-OCT). A secondary objective was to quantify inter-observer agreements of AS-OCT and SD-OCT assessments. METHODS Seventeen consecutive subjects (33 eyes) were recruited from the study hospitals Glaucoma clinic. Gonioscopy was performed by a glaucomatologist masked to OCT results. OCT images were read independently by 2 other glaucomatologists masked to gonioscopy findings as well as each others analyses of OCT images. RESULTS Totally 84.8% and 45.5% of scleral spurs were visualized in AS-OCT and SD-OCT images respectively (P<0.01). The agreement for angle closure between AS-OCT and gonioscopy was fair at k=0.31 (95% confidence interval, CI: 0.03-0.59) and k=0.35 (95% CI: 0.07-0.63) for reader 1 and 2 respectively. The agreement for angle closure between SD-OCT and gonioscopy was fair at k=0.21 (95% CI: 0.07-0.49) and slight at k=0.17 (95% CI: 0.08-0.42) for reader 1 and 2 respectively. The inter-reader agreement for angle closure in AS-OCT images was moderate at 0.51 (95% CI: 0.13-0.88). The inter-reader agreement for angle closure in SD-OCT images was slight at 0.18 (95% CI: 0.08-0.45). CONCLUSION Significant proportion of scleral spurs were not visualised with SD-OCT imaging resulting in weaker inter-reader agreements. Identifying other angle landmarks in SD-OCT images will allow more consistent angle closure assessments. Gonioscopy and OCT imaging do not always agree in angle closure assessments but have their own advantages, and should be used together and not exclusively.

A Cytomegalovirus Retinitis Screening Program: Evaluation of Enrollment Criteria for HIV Patients in Singapore

Abstract Purpose: Identification of optimal enrollment criteria for a CMVR screening program suitable for a resource-limited environment. Methods: A prospective audit was performed on newly diagnosed HIV patients referred for CMVR screening with any of the following four criteria: (1) visual symptoms, (2) low CD4+ counts (<50 cells/µL), (3) AIDS-defining illnesses (ADI), and/or (4) opportunistic infections (OI). Odds ratios for each of the demographic factors and enrollment criteria were calculated. Sensitivities, specificities, and workload reduction for the various combinations were determined. Results: A total of 348 screening visits for 176 HIV patients were performed. While individually only ADI was statistically significant for increased CMVR risk, the combination of CD4+ counts <50 cells/μL with either ADI or visual symptoms or all 3 criteria were also statistically significant. Two enrollment criteria, ADI and ADI with CD4+ <50 cells/μL, demonstrated good sensitivities, specificities, and workload reduction. Conclusion: We propose ADI and possibly CD4+ counts <50 cells/μL as enrollment criteria for CMVR screening.

Intraoperative centration during small incision lenticule extraction (smile)

Abstract To evaluate intraoperative decentration from pupil center and kappa intercept during small incision lenticule extraction (SMILE) and its impact on visual outcomes. This was a retrospective noncomparative case series. A total of 164 eyes that underwent SMILE at the Singapore National Eye Center were included. Screen captures of intraoperative videos were analyzed. Preoperative and 3 month postoperative vision and refractive data were analyzed against decentration. The mean preoperative spherical equivalent (SE) was −5.84 ± 1.77. The mean decentration from the pupil center and from kappa intercept were 0.13 ± 0.06 mm and 0.47mm ± 0.25 mm, respectively. For efficacy and predictability, 69.6% and 95.0% of eyes achieved a visual acuity (VA) of 20/20 and 20/30, respectively, while 83.8% and 97.2% of eyes were within ±0.5D and ±1.0D of the targeted SE. When analyzed across 3 groups of decentration from the pupil center (<0.1 mm, 0.1–0.2 mm, and >0.2 mm), there was no statistically significant association between decentration, safety, efficacy, and predictability. When analyzed across 4 groups of decentration from kappa intercept (<0.2 mm, 0.2–<0.4 mm, 0.4–<0.6 mm, and ≥0.6 mm), there was a trend toward higher efficacy for eyes with decentration of kappa intercept between 0.4 and <0.6 mm (P = .097). A total of 85.4% of eyes in the 0.4 to <0.6 mm group had unaided distance VA of 20/20 or better, as compared to only 57.8% of eyes in ≥0.6 mm group. Decentration of 0.13 mm from the pupil center does not result in compromised visual outcomes. Decentration of greater than 0.6 mm from the kappa intercept may result in compromised visual outcomes. There was a trend toward better efficacy in eyes which had decentered treatment from 0.4 to <0.6 mm from the kappa intercept. Patients with a large kappa intercept (>0.6 mm) should have their lenticule created 0.4 to 0.6 mm from the kappa intercept and not close to the pupil.

Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS)—report 4: analysis and outcome of scleritis in an East Asian population

BackgroundThe purpose of this study is to evaluate the spectrum of scleritis from database of Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS) at a tertiary eye referral eye institute in Singapore. Clinical records of 120 patients with scleritis from a database of 2200 patients from Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS) were reviewed.Results56.6% were females, with a mean age of 48.6 ± 15.9 years. 75 (62.5%) had diffuse anterior scleritis, 25 (20.8%) had nodular anterior scleritis, 7 (5.8%) had necrotizing anterior scleritis and 13 (10.8%) had posterior scleritis. Ocular complications were observed in 53.3% of patients, including anterior uveitis (42.5%), raised intraocular pressure (12.5%), and corneal involvement (11.7%). Autoimmune causes were associated with 31 (25.8%) of patients, and 10 (8.3%) patients had an associated infective etiology, much higher than Caucasian studies. 53.3% of patients were treated with oral corticosteroids while 26.7% required immunosuppressives.ConclusionsInfective etiology needs to be considered in patients of scleritis from Asian origin. In our study and in OASIS database, scleritis was associated with systemic autoimmune disease and ocular complications.

Effect of head tilt on repeatability of optic nerve head parameters using cirrus spectral-domain optical coherence tomography

AIM To assess the repeatability of measuring optic nerve head (ONH) parameters using the Cirrus optical coherence tomography (OCT), as well as to assess the effect of head tilt on these measurements. METHODS Thirty healthy participants with no evidence of glaucoma were recruited for the study. Visual acuity, intraocular pressure, standard automated perimetry and ocular examination were performed for each participant. One eye was then randomly selected and scanned undilated with the Cirrus OCT in 3 positions (neutral, 30° right tilt and 30° left tilt). RESULTS Data collected from 29 eyes were used for analysis. One patient was omitted due to poor scan quality. The repeatability of the ONH parameters was analyzed using analysis of variance, coefficient of variation (COV) and intraclass correlation coefficient (ICC). Analysis of variance showed no statistically significant difference between 3 scans in a single position. There was good agreement between measurements (ICC 0.919-0.996, COV 1.94%-5.48%). Even with the presence of head tilt, repeated scans in the 3 positions showed good agreement as well (ICC 0.888-0.996, COV 2.04%-5.39%). CONCLUSION Serial measurements of ONH parameters using the Cirrus OCT are found to have good repeatability. The ONH parameters with Cirrus OCT also maintain good repeatability despite head tilt.