Visual Field Tests: A Narrative Review of Different Perimetric Methods.

Visual field (VF) testing dates back to fifth century B.C. It plays a pivotal role in the diagnosis, management, and prognosis of retinal and neurological diseases. This review summarizes each of the different VF tests and perimetric methods, including the advantages and disadvantages and adherence to the desired standard diagnostic criteria. The review targets beginners and eye care professionals and includes history and evolution, qualitative and quantitative tests, and subjective and objective perimetric methods. VF testing methods have evolved in terms of technique, precision, user-friendliness, and accuracy. Consequently, some earlier perimetric techniques, often still effective, are not used or have been forgotten. Newer technologies may not always be advantageous because of higher costs, and they may not achieve the desired sensitivity and specificity. VF testing is most often used in glaucoma and neurological diseases, but new objective methods that also measure response latencies are emerging for the management of retinal diseases. Given the varied perimetric methods available, clinicians are advised to select appropriate methods to suit their needs and target disease and to decide on applying simple vs. complex tests or between using subjective and objective methods. Newer, rapid, non-contact, objective methods may provide improved patient satisfaction and allow for the testing of children and the infirm.

Profile of Patients Treated with Intravitreal Anti-Vascular Endothelial Growth Factor Injections in Bhutan.

Purpose: Ocular vascular diseases are common causes of visual impairment and blindness, for which anti-vascular endothelial growth factor (anti-VEGF) is the first-line therapy. Current study describes the profile of patients receiving intravitreal anti-VEGF injections (IVI), and gender variation in Bhutan. The study was designed to inform national health policy. Study Design: Retrospective cross-sectional study. Methods: We reviewed the surgical registers of the vitreoretinal (VR) units across Bhutan over three years. Patient demography, clinical findings, diagnostic tests performed, and diagnoses or indications for IVI were logged. A descriptive analysis was performed. Results: Despite limited availability of anti-VEGF, a total of 381 patients received IVI in operating theatres as mandated by the national guidelines. The majority of patients were males (230, 60.4%, p = 0.004). The mean age was 65.2 ± 13.5 years (range 13 years to 90 years), and a median of 69 years. The majority of the treated eyes (117, 30.7%) had BCVA <3/60 to light perception (PL), and another 51 eyes (13.4%) had < 6/60 to 3/60. The most common indication for IVI was neovascular age-related macular degeneration (nAMD) (168 cases, 42.2%), followed by retinal vein occlusion (RVO) (132 cases, 34.6%), diabetic macular oedema (DMO) and retinopathy (DR) (50 cases, 13.1%), and myopic choroidal neovascular membrane (11 cases, 0.03%). Conclusion: Limited human resources for managing VR diseases in Bhutan are compounded by economic and geographic challenges. With increasing VR diseases such as nAMD and myopia and complications of systemic diseases such as DR, DMO and RVO, there is a need to improve VR services. Currently, anti-VEGF is procured only for a pooled patients requiring IVI, and patients are lost due to longer waiting periods. Bhutan needs to assess if females are reporting less or are not receiving treatment due to cultural barriers and social stigma.

Prevalence and severity of diabetic retinopathy at first presentation to vitreoretinal services in Bhutan: a 3-year national study.

PURPOSE: To determine the prevalence and severity of diabetic retinopathy (DR) at first presentation among diabetic patients attending national vitreoretinal (VR) services in Bhutan STUDY DESIGN: Retrospective cross-sectional study METHODS: We included all diabetic patients in Bhutan who presented for retinal evaluation for the first time over a 3-year period (2013-2016). Data including demography, clinical details, diagnostic tests, and clinical staging of DR were analyzed. RESULTS: A total of 843 diabetic patients, aged 57.2 ± 12.0 (range 18-86) years, were enrolled. The majority were male (452, 53.6%; cumulative frequency [cf] 391, 46.4%; P = .14) and from urban settings (570, 67.6%; cf 273; 32.4%) and did not have modern schooling (555, 65.8%). Hypertension was the most common systemic comorbidity (501, 59.4%). The prevalence of DR was 42.7%, with mild nonproliferative DR (NPDR) being the most common type (187, 51.9%), followed by moderate NPDR (88, 24.4%) and proliferative DR (45, 12.5%). In addition, 120 patients had clinically significant macular edema (CSME), with a prevalence of 14.2%. Best-corrected visual acuity (BCVA) of 6/60 or worse occurred in 231 eyes (13.7%), and 41 patients (4.86%) had BCVA of 6/60 or worse bilaterally due to DR/CSME. A logistic regression model indicated that the major determinant of DR was the duration of diabetes, the odds rising by 1.27× with each year of disease (P < .0001). CONCLUSION: The prevalence of DR, including CSME, was high. Although a national DR screening program is established in Bhutan, there is a need to accelerate health education, community screening, and referral systems to reduce the prevalence of DR and CSME.

Rural-urban differences in myopia prevalence among myopes presenting to Bhutanese retinal clinical services: a 3-year national study.

PURPOSE: To determine the prevalence and demographic characteristics of myopia among patients presenting to the national vitreo-retinal (VR) services in Bhutan. METHODS: The records of the VR clinic at the apex national referral centre, providing the only VR services in the country, were reviewed to identify all new myopia patients over three years. Thus, we surveyed all referrals nationally. The patients were categorised into urban and rural females and males. We assessed myopia prevalence in each group by occupational and educational categories. We examined univariate prevalence data and a multivariate logistic regression (MLR) identified independent factors. RESULTS: Of 2913 cases 1544 (53.0%) were males. Females presented earlier (mean ±SD): overall 45.7 ± 21.9 cf. 48.6 ± 21.6 years, p = 0.003, and among myopes 23.9 ± 13.5 cf. 27.6 ± 18.6 years, p = 0.032. Myopia constituted 92.1% of refractive error, an overall prevalence of 12.3%. Myopia was more common among females (p = 0.01) and urbanites (p = 0.02). Myopia prevalence was highest among urban females (20.9%), followed by urban males (11.9%), rural females (6.8%), and rural males (5.2%). Logistic regression revealed that the odds of having myopia were increased by being a student (4.96 ×) or professional (1.96 ×), and decreased by rural living (1.75 ×), all p ≤ 0.038. CONCLUSIONS: This is the first study on myopia in Bhutan. As observed throughout East and Southeast Asia, the prevalence of myopia was higher in females and urbanites and positively associated with formal education. Given known risk factors, these prevalences may be driven by educational pressures and reduced time spent outdoors.

Recovery dynamics of multifocal pupillographic objective perimetry from tropicamide dilation.

PURPOSE: To study the pupillary system by combining mydriasis and multifocal pupillographic objective perimetry (mfPOP). In particular, we explored how the dynamics of recovery differ for concurrently measured direct and consensual sensitivity, response delay, and signal-to-noise ratios (SNRs) for binocular mydriasis. METHODS: We recruited 26 normal participants, all with brown irides. The dichoptic mfPOP stimuli concurrently assessed 44-region/eye and both pupils. Two pre-dilation tests were followed by pairs of repeated tests at 1, 2, 4, 6, 8, 12, 24, and 48 h following dilation of both pupils with 1% tropicamide. Three subjects were retested with only the right pupil dilated. Linear models determined the independent effects of mydriasis upon the per-region and pupil measures over time. RESULTS: Post-dilation, the per-region delays initially decreased by 16.3 ± 6.02 ms (mean ± SE) (p < 0.0001, cf. baseline of 471.1 ± 4.36 ms), then increased to slower than baseline by 17.42 ± 5.57 ms after 4 h (p < 0.002), recovering to baseline at 8 h. By comparison, per-region sensitivities (constriction amplitudes) were still reduced by - 6.20 ± 0.70 µm at 8 h (p < 0.0001, cf. baseline of 21.1 ± 0.55 µm), recovered at 24 h, but rebounded at 48 h (p = 0.005). The SNRs for sensitivities and delays both recovered by 8-12 h. Across all the data, sensitivities reduced by 2.67 ± 0.25 µm/decade of age, and delay increased by 15.4 ± 1.98 ms/decade (both p < 0.00001). Data from 3 of the 26 subjects who repeated the testing for monocular dilation found that consensual response sensitivities were larger than direct for 8 h (p < 0.018). CONCLUSIONS: The per-region sensitivities were affected for longer than SNRs or delays. Strong early SNRs indicated proportionately lower pupil noise for larger pupil diameters. Following mydriasis with tropicamide 1%, the constriction amplitude measurements with mfPOP should be considered only after 48 h, but time-to-peak can be measured after 8-12 h.

Correlates of problematic unrecorded alcohol consumption in Sikkim, Northeast India - Results from a cross-sectional pilot survey.

The magnitude and consequences of unrecorded alcohol consumption, defined as home brewed or clandestinely produced illicit liquor or surrogate alcoholic beverage has been little investigated in India. A significant portion of all alcohol consumed globally is unrecorded, therefore these consumers constitute a significant population. Sikkim, a province in Northeast India, lies in the foothills of the Himalayas. Unrecorded alcohol use is traditionally prevalent, with more than ten types available. This study investigated correlates of problematic unrecorded alcohol consumption in rural and urban communities of Sikkim. A cross-sectional, community-based pilot survey was conducted. Intensive case-finding recruited current heavy users (at least 3 days/week) of unrecorded alcohol of either sex above 16 years of age. On enrolment, participants responded to a socio-demographic instrument including 12 questions on their pattern of alcohol consumption and a 4-item CAGE questionnaire. Alcohol problems exist significantly among the young adult population. Although consumption of unrecorded alcohol is traditional in Sikkim, it has emerged as an important public health problem, with alarmingly high rates of problematic consumption. This is also expected to have significant economic costs. Therefore, prevention and treatment measures are an urgent need as well as policy decisions on production and sales of unrecorded alcohol.

Rapid assessment of avoidable blindness in Bhutan.

AIM: To conduct a rapid assessment of avoidable blindness survey in Bhutan to obtain estimates of blindness, visual impairment, and cataract surgical coverage, outcomes and barriers among persons ≥50 years old. METHODS: A total of 82 clusters of 50 people ≥50 years were selected using probability proportionate to size sampling. Eligible participants were selected from households using compact segment sampling, and underwent ophthalmic examination for visual acuity, followed by penlight and direct ophthalmoscopy. Participants with cataract were interviewed regarding surgical outcomes and barriers to surgery. RESULTS: Overall, 4046 of 4100 persons enumerated (98.7%) underwent ophthalmic examination. Adjusting for age and sex, the prevalence of bilaterally blind persons with available correction was 1.5% (95% confidence interval 1.09-1.89). Most blindness (67.1%) and severe visual impairment (74.1%) resulted from cataract, but 22.1% resulted from posterior segment pathology. Cataract surgical coverage for bilaterally blind persons was 72.7%. Almost 90% of patients reported moderate or good satisfaction, despite poor surgical outcomes in 23.6%. CONCLUSIONS: The prevalence of blindness in people aged ≥50 years in Bhutan was relatively low when compared with neighboring countries and World Health Organization sub-region estimates. Areas for improvement include community outreach, surgical outcomes, and posterior segment diseases.