Impact of cardiometabolic factors on retinal vasculature: A 3 × 3, 6 × 6 and 8 × 8-mm ocular coherence tomography angiography study.

BACKGROUND: Ocular coherence tomography angiography (OCTA) is available in varying size and resolution. We sought to characterise associations of cardiometabolic factors with retinal microvascular changes using 3 × 3, 6 × 6 and 8 × 8-mm OCTA scans to determine differences in detection with varying scan size. METHODS: Cross-sectional study of 247 cardiovascular patients from a single-centre tertiary-care hospital. Demographic, comorbidity and medication data were obtained. Patients underwent 3 × 3, 6 × 6 and 8 × 8-mm macula OCTA scanning using Carl Zeiss CIRRUS HD-OCT Model 5000. Angioplex and AngioTool software was used to quantify vascular parameters in the superficial capillary plexus. RESULTS: Increasing age, hypertension, dyslipidaemia, diabetes, chronic kidney disease, coronary artery disease and peripheral vascular disease were associated with reductions in vessel density, vessel perfusion, average vessel length and/or junction density in 3 × 3-mm OCTA (P < .05 for all). Conversely, smoking was associated with increased vessel density, vessel length and junction density in 3 × 3-mm OCTA (P < .05 for all). Associations of vessel abnormalities with cardiometabolic factors were progressively weakened and statistically attenuated in 6 × 6 and 8 × 8-mm OCTA scans. In multivariate analyses, dyslipidaemia remained an independent predictor of reduced vessel density, average vessel length and junction density (P < .05). CONCLUSIONS: Cardiometabolic factors are associated with multiple retinal microvascular changes in 3 × 3-mm OCTA scans. These associations were weakened and progressively attenuated in OCTA scans of larger 6 × 6 and 8 × 8-mm size. These findings advance our understanding of microcirculatory dysfunction and may have future implications for the screening and management of patients with cardiometabolic risk factors. Additional studies are required to further investigate these important associations.

Long-term survival rates of patients undergoing vitrectomy for diabetic retinopathy in an Australian population: a population-based audit.

IMPORTANCE: Five-year survival rates in patients undergoing vitrectomy for diabetic retinopathy (DR) vary from 68% to 95%. No study has been conducted in an Australian population. BACKGROUND: We aimed to determine the survival rates of patients undergoing diabetic vitrectomy in an Australian population. DESIGN: Retrospective audit, tertiary centre hospitals and private practices. PARTICIPANTS: All individuals in South Australia and the Northern Territory who underwent their first vitrectomy for diabetic complications between January 1, 2007 and December 31, 2011. METHODS: An audit of all eligible participants has been completed previously. Survival status as of July 6, 2018 and cause of death were obtained using SA/NT DataLink. Kaplan-Meier survival curves and multivariate cox-regressions were used to analyse survival rates and identify risk factors for mortality. MAIN OUTCOME MEASURES: Five-, seven- and nine-year survival rates. RESULTS: The 5-, 7- and 9-year survival rates were 84.4%, 77.9% and 74.7%, respectively. The most common cause of death was cardiovascular disease. Associated with increased mortality independent of age were Indigenous ethnicity (HR = 2.04, 95% confidence interval [CI]: 1.17-3.57, P = 0.012), chronic renal failure (HR = 1.76, 95% CI: 1.07-2.89, P = 0.026) and renal failure requiring dialysis (HR = 2.32, 95% CI: 1.25-4.32, P = 0.008). CONCLUSIONS AND RELEVANCE: Long-term survival rates after diabetic vitrectomy in Australia are similar to rates reported in other populations. Indigenous ethnicity and chronic renal failure were the most significant factors associated with long-term mortality. This information can guide allocation of future resources to improve the prognosis of these high risk groups.

Visual outcomes following vitrectomy for diabetic retinopathy amongst Indigenous and non-Indigenous Australians in South Australia and the Northern Territory.

IMPORTANCE: Visual outcomes following diabetic vitrectomy have not previously been studied in an Australian population. BACKGROUND: This analysis aimed to determine the rate of, and factors associated with visual success following diabetic vitrectomy performed for Indigenous and non-Indigenous Australians, and investigate factors predisposing to early progression to diabetic retinopathy (DR) requiring vitrectomy. DESIGN: Retrospective, population-based audit. PARTICIPANTS: All patients undergoing vitrectomy for the complications of DR in South Australia (SA) and the Northern Territory (NT) between 2007 and 2011. METHODS: Medical records were audited and data collected, including demographics, diabetic history, past treatment for DR, indication for vitrectomy and visual acuity pre and postoperatively. MAIN OUTCOME MEASURES: Visual success (gain of ≥15 ETDRS letters) at 6 and 12 months, postoperatively. RESULTS: A total of 495 diabetic vitrectomies, for 404 eyes of 335 patients were performed in SA and NT between 2007 and 2011. 77 (23%) patients requiring diabetic vitrectomy were Indigenous Australians. 87% of patients undergoing diabetic vitrectomy had stable or improved vision at 1 year, postoperatively. There was no significant difference between indigenous and non-indigenous eyes achieving visual success (P = 0.929). Timely preoperative laser treatment (P = 0.03) and preoperative visual acuity (P = 0.01) were the predominant factors associated with visual success. CONCLUSIONS AND RELEVANCE: Indigenous patients are just as likely to have improved vision following diabetic vitrectomy as non-Indigenous Australians. However, the small subset of indigenous patients with blind eyes prior to vitrectomy are significantly less likely to improve from surgery. The underlying factors associated with poor outcomes in this group requires further exploration.

Biochemical analysis of the living human vitreous.

BACKGROUND: To date, our understanding of the biochemical composition of the living human vitreous relies on extrapolations from animal or human post-mortem studies. METHODS: This was a cross-sectional study of vitreous samples from 27 individuals scheduled for retinal surgery within a tertiary hospital. From each vitreous sample, the concentrations of sodium, potassium, chloride, calcium, magnesium, glucose, lactate, ß- hydroxybutyrate, copper, zinc, selenium, iron, ferritin and transferrin and osmolality were measured. Perioperative serum samples were also obtained for comparison. RESULTS: The following vitreous mean ± standard deviation (95% confidence interval of the mean) was observed for each analyte: sodium, 146.7 ± 3.3 (145.4-148.0) mmol/L; potassium, 5.73 ± 0.86 (5.39-6.08) mmol/L; chloride, 121.6 ± 2.6 (120.6-122.7) mmol/L; calcium, 1.128 ± 0.518 (0.923-1.333) mmol/L; magnesium, 0.900 ± 0.158 (0.838-0.962) mmol/L; glucose, 2.97 ± 0.98 (2.58-3.36) mmol/L; lactate, 3.97 ± 1.09 (3.54-4.40) mmol/L; osmolality, 289.5 ± 6.9 (286.6-292.5) mOsm/kg; BOHB, 0.0937 ± 0.0472 (0.0750-0.1124) mmol/L; copper, 0.519 ± 0.269 (0.412-0.625) µmol/L; zinc, 1.95 ± 1.09 (1.52-2.38) µmol/L; selenium, 0.1035 ± 0.0276 (0.0923-0.1146) µmol/L; iron, 3.11 ± 1.40 (2.56-3.66) µmol/L; ferritin, 19.5 ± 10.3 (15.5-23.6) µg/L; transferrin, 0.0878 ± 0.0526 (0.0670-0.1086) g/L. Vitreous biochemistry was not significantly different between male and female participants. Vitreous biochemistry was significantly different between non-diabetic and diabetic participants. Vitreous biochemistry was significantly different from the vitreous substitute BSS Plus (Alcon, USA). The vitreous extracted from living humans was markedly different from the commonly reported reference values obtained from animal studies. CONCLUSIONS: The current data provide hitherto unavailable information about the biochemical composition of the living human vitreous.

Glucose-induced temporary visual recovery in primary open-angle glaucoma: a double-blind, randomized study.

PURPOSE: To investigate the effect of topical glucose on visual parameters in individuals with primary open-angle glaucoma (POAG). DESIGN: Double-blind, randomized, crossover study. PARTICIPANTS: Nondiabetic pseudophakic patients with definite POAG were recruited; 29 eyes of 16 individuals participated in study 1. A follow-up study (study 2) included 14 eyes of 7 individuals. INTERVENTION: Eyes were randomly allocated to receive 50% glucose or saline eye drops every 5 minutes for 60 minutes. MAIN OUTCOME MEASURES: The contrast sensitivity and best-corrected logarithm of the minimum angle of resolution (logMAR). RESULTS: The 50% glucose reached the vitreous in pseudophakic but not phakic individuals. Glucose significantly improved the mean contrast sensitivity at 12 cycles/degree compared with 0.9% saline by 0.26 log units (95% confidence interval [CI], 0.13-0.38; P < 0.001) and 0.40 log units (95% CI, 0.17-0.60; P < 0.001) in the follow-up study. The intraocular pressure, refraction, and central corneal thickness were not affected by glucose; age was not a significant predictor of the response. CONCLUSIONS: Topical glucose temporarily improves psychophysical visual parameters in some individuals with POAG, suggesting that neuronal energy substrate delivery to the vitreous reservoir may recover function of "sick" retinal neurons.

Perspective on ophthalmic support in countries of the developing world.

There are over 300 million people living in the world today who are visually impaired and a further 45 million who are blind. The large majority (90%) of these people live in developing countries, and up to 75% of blindness are avoidable. With cataracts being the major cause of blindness and visual impairment, many ophthalmic aid programmes are aimed at alleviating the enormous burden caused by this readily treatable disease. Having said that, caution should be exercised that short surgical visits to remote rural areas that are not coordinated with local national eye care managers should be discouraged because they do little for the development of sustainable eye care programmes. With this in view, it has become imperative to design blindness prevention and ophthalmic support programmes that are workable, comprehensive, economical and sustainable.

Pilot randomized trial of a nanopulse retinal laser versus conventional photocoagulation for the treatment of diabetic macular oedema.

BACKGROUND: To assess the efficacy of a new nanopulse laser, retinal regeneration therapy for the treatment of diabetic macular oedema. DESIGN: Randomized, non-inferiority, trial. PARTICIPANTS: 20 eyes of 17 subjects in the retinal regeneration therapy group and 18 eyes of 14 subjects in the conventional group were analysed. METHODS: The treatment group received retinal regeneration therapy laser, and the control group received photocoagulation. MAIN OUTCOME MEASURES: The primary outcome was the optical coherence tomography-measured change in central retinal thickness at 6 months. A secondary outcome was the change in logarithm of minimum angle of resolution visual acuity at 6 months. Non-inferiority required the one-sided 95% confidence interval of the mean retinal thickness reduction after retinal regeneration therapy to be within 35 µm of the reduction after control laser. RESULTS: When outliers were included in the dataset, the difference in retinal thickness reduction by analysis of covariance was 10.9 (standard deviation 17.6) mm in favour of the control laser. The difference between groups in retinal thickness reduction was 40.8 mm. If two extreme outliers were excluded, the difference was 5.6 (standard deviation 14.2) mm in favour of the retinal regeneration therapy laser, and the D optical coherence tomography was 18.5 mm. The visual acuity difference between groups was 0.059, meeting non-inferiority requirements. CONCLUSIONS: Although retinal thickness reduction was not unambiguously non-inferior, in the short-term, retinal regeneration therapy approximates the clinical efficacy of conventional photocoagulation, stabilizing visual acuity and providing motivation for larger trials assessing retinal regeneration therapy.

Killing two birds with one stone: the potential effect of cataract surgery on the incidence of primary angle-closure glaucoma in a high-risk population.

BACKGROUND: To estimate the proportion of cataract surgery performed at various visual acuity and lens opacity thresholds that would coincidentally treat early angle-closure disease, and to estimate the effect of this surgery on the incidence of primary angle-closure glaucoma. DESIGN: Cross-sectional, population-based survey in Meiktila, Myanmar. PARTICIPANTS: Total of 2076 inhabitants, 40 years of age and over were included. METHODS: Eyes with cataract-induced visual impairment, and primary angle-closure disease were identified. Analyses were stratified by various pinhole-corrected visual acuity and Lens Opacity Classification System III scores thresholds. MAIN OUTCOME MEASURES: The dual role of cataract surgery in primary cataract treatment and primary angle-closure glaucoma prevention was estimated. RESULTS: Of 4153 eyes available for analysis, 261 eyes were either primary angle-closure suspect or primary angle closure; 975 eyes had a visual acuity of <6/18 and Lens Opacity Classification System III score ≥ 3 on the nuclear or cortical scales. Of these, 86 eyes had either primary angle-closure suspect or primary angle closure. If cataract surgery were performed on all 975 eyes, this would potentially prevent up to 86 cases of primary angle-closure glaucoma in this population; 8.82% (95% confidence interval 7.12-10.78%) of the cataract surgery would address the cataract and prevent primary angle-closure glaucoma. This would achieve a 38.46% (95% confidence interval 20.23-59.43%) relative reduction in the incidence of primary angle-closure glaucoma in the adult population. CONCLUSION: In populations with a high prevalence of both visually significant cataract and angle-closure disease, quality cataract extraction can serve a dual role of visual restoration and reducing the incidence of angle-closure disease in the population: killing two birds with one stone.

Cataract surgical coverage and self-reported barriers to cataract surgery in a rural Myanmar population.

PURPOSE: The aim of this study is to determine the cataract surgical coverage and investigate the barriers to cataract surgery as reported by those with cataract-induced visual impairment in rural Myanmar. METHODS: A cross-sectional, population-based survey of inhabitants 40 years of age and over from villages in the Meiktila District (central Myanmar); 2481 eligible participants were identified and 2076 participated. Data recording included corrected visual acuity, dilated slit lamp examination and stereoscopic fundus examination. Lens opacity was graded using the Lens Opacities Classification System III. Participants with cataract-induced visual impairment (acuity < 6/18 in better eye) were also invited to respond to a verbal questionnaire about barriers to cataract surgery. RESULTS: Cataract surgical coverage for visual acuity cut-offs of <6/18, <6/60 and <3/60 was 9.74%, 20.11% and 22.3%, respectively, for people and 4.18%, 9.39% and 13.47%, respectively, for eyes. Cataract surgical coverage was higher for men than women, but gender was not associated with refusal of services. Of the 239 who responded to the extra questionnaire, 216 were blind or had low vision owing to cataract. Three quarters refused referral for surgery: cost and fear of surgery were the most frequently reported barriers. CONCLUSION: Cost plays a large role in the burden of cataract in this region. Implementation of educational programmes, reforms to local health service and subsidization of ophthalmic care may improve the uptake of cataract surgery.

Awareness of diabetic eye disease among general practitioners and diabetic patients in Yangon, Myanmar.

BACKGROUND: Diabetes is an increasing problem in Myanmar with more than three million people affected. There are no data on awareness of diabetic retinopathy among the general practitioners (GPs) or diabetic population of Myanmar. This study aims to evaluate the awareness of diabetes-related eye disease among GPs and diabetic patients in Yangon, Myanmar. DESIGN: A cross-sectional survey. METHODS: From the Myanmar Medical Association Registry of 978 practicing GPs in Yangon, 200 were randomly selected and a structured questionnaire was sent to each. Each GP was asked to give a separate questionnaire to the first five diabetic patients who attended their practice. RESULTS: One hundred GPs and 480 patients returned the questionnaires. Although 99% of GPs were aware that diabetes could result in loss of vision, 49% never examined the fundi of their diabetic patients. Of the diabetic patients, 86% were aware that diabetes could damage their eyesight. Although 92% realized they should visit an ophthalmologist regularly, only 57% had seen an ophthalmologist. Patients who never attended school were less likely to visit an ophthalmologist than those with tertiary education (odds ratio 0.24; 95% confidence interval 0.09, 0.66). Patients with diabetes for less than 2 years were less likely to visit an ophthalmologist than those with diabetes for more than 10 years (odds ratio 0.21; 95% confidence interval 0.9, 0.44). There was no association between age, gender or work status and the likelihood of having seen an ophthalmologist. CONCLUSION: Although both GPs and diabetic patients are aware of the need for regular fundal screening, just over half the patients had been screened. There exists a need for programmes in Myanmar to induce a behavioural change in diabetic patients with regards to screening examinations.

Sutureless vitrectomy.

Sutureless vitrectomy has rapidly been accepted as an essential part of a vitreoretinal surgical setup. The size and structure of the wound along with near intact conjunctival covering makes the incision self-sealing and safe. This allows the vitrectomy instruments to be used without creating an initial limited peritomy to expose bare sclera, and obviates the need for sutures at the end of the procedure. Wound construction is the essential step in ensuring postoperative wound stability. Both one-step and two-step wound constructions have been described. Key points include an oblique, tunneled approach to ensure a valve-like effect as well as misalignment of conjunctival and scleral wounds by displacing conjunctiva during construction. Advantages include decreased operative times in certain cases and decreased postoperative inflammation, early postoperative rehabilitation, improved patient comfort, and minimal conjunctival damage. Complications are based around wound competence, hypotony, and its relationship to endophthalmitis rates. Early reports highlighted an increase in endophthalmitis though further studies are required to accurately assess the incidence. Endophthalmitis has not been reported in cases that underwent fluid/air exchange. This review focuses on techniques, benefits, complications, personal experiences, and the safety profiles of sutureless vitrectomy systems. A literature review was undertaken using 'Medline' and 'Pubmed'. Search terms included sutureless vitrectomy, 20 gauge, 23 gauge, 25 gauge, and transconjunctival and small gauge vitrectomy.

Prevalence of trachoma-related trichiasis and corneal opacity in rural Myanmar: the Meiktila Eye Study.

OBJECTIVE: To describe the prevalence of trachomatous trichiasis and corneal opacity (CO) within central Myanmar. DESIGN: Population-based cross-sectional ophthalmic survey. PARTICIPANTS: Random, stratified, cluster sampling of the inhabitants > or =40 years of age from villages in the Meiktila District was performed; 2481 eligible participants were identified and 2076 participated in the study. METHODS: Visual acuity was measured using an E Snellen chart at 6 meters. Lid, ocular surface, and anterior segment examinations were performed at the slit lamp. MAIN OUTCOME MEASURES: Trachoma was graded as trachomatous trichiasis (TT) or CO according to the World Health Organization grading system. RESULTS: The population prevalence of trachoma (TT and CO) was 2.6% (95% confidence interval [CI]. 1.67%-3.42%). For every 1-year increase in age, the odds of trachoma increased by 5.3% (95% CI, 4.9%-5.7%). There was no significant effect of gender on the prevalence of trachoma (P = 0.5). No formal schooling was a strong predictor of trachoma (odds ratio, [OR], 4.9; 95% CI, 3.9-6.1), and having <3 children in the house was protective (OR, 0.75; 95% CI, 0.61-0.93); however, neither occupation nor the number of people in a household had an effect on trachoma. CONCLUSIONS: The prevalence of blinding trachoma in central Myanmar remains relatively low. This is a tribute to the success of the Burma Trachoma Control Program and demonstrates the need for such a program to remain an integral part of public health care and community health services to further diminish the prevalence of this condition. This will be facilitated by a focus on trachoma risk factors and further research into the prevalence of inflammatory trachoma within the pediatric population.

Association between stature, ocular biometry and refraction in an adult population in rural Myanmar: the Meiktila eye study.

PURPOSE: To study the association between adult stature and ocular biometric parameters and refraction. METHODS: In a population-based cross-sectional ophthalmic survey of 2418 adults (> or = 40 years old) living in the rural villages in central Myanmar, height and weight were measured using a standardized protocol, and body mass index was calculated. Non-cycloplegic refraction and corneal curvature were determined by an autorefractor. Ultrasound pachymetry was performed and ocular biometry, including axial length, anterior chamber depth, lens thickness and vitreous chamber length were measured using A-mode ocular ultrasonography. RESULTS: Height and weight were significantly correlated with age, gender and all the ocular biometric parameters, except lens thickness. After adjusting for age and gender, taller and heavier persons had eyes with longer axial length, deeper anterior and vitreous chambers, and flatter and thicker corneas than shorter persons. Height was not significantly correlated with refraction, and heavier persons tended to be less myopic (P < 0.001). Multivariate linear regression models revealed consistent results with the findings for association between height, weight and ocular biometry and refractive error. CONCLUSIONS: Adult stature is independently associated with vitreous chamber length and corneal radius in this Burmese population. Heavier persons were slightly hyperopic.

Antemortem vitreous potassium may strengthen postmortem interval estimates.

The purpose of this letter is to highlight that postmortem interval estimates using vitreous potassium concentrations may be further optimised by calibration against antemortem vitreous samples.

Corneal thickness and intraocular pressure in a nonglaucomatous Burmese population: the Meiktila Eye Study.

OBJECTIVE: To determine correlates of central corneal thickness (CCT) and its relationship to intraocular pressure (IOP) in a Burmese population. METHODS: We performed a population-based survey of inhabitants 40 years or older in Myanmar; of 2076 participants, data from 1909 nonglaucomatous subjects who underwent ultrasound pachymetry and Goldmann applanation tonometry were analyzed. Linear mixed effects models adjusting for nonindependence of right and left eye data were constructed. RESULTS: Mean (SD) CCT was 521.9 (33.3) microm, and the mean (SD) IOP was 14.5 (3.4) mm Hg. Intraocular pressure and spherical equivalent were significant predictors of CCT (P < .001 and P = .01, respectively). Age, sex, body mass index, and corneal curvature were not significant predictors. Central corneal thickness was the only significant predictor of IOP (ie, an increase of 100 microm in CCT predicted an increase of 1.3 mm Hg in IOP). The Spearman correlation between CCT and IOP for the right and left eyes was highly significant (P < .001), but the Spearman rank correlation values (R(2) = 0.016 and R(2) = 0.017, respectively) were weak. CONCLUSIONS: The CCT in this Burmese population was significantly associated with IOP and spherical equivalent. The weak association between CCT and IOP is consistent with that of other population-based studies. Other corneal factors are likely to influence Goldmann applanation tonometry.

Improving patient satisfaction through information provision.

BACKGROUND: This study aims to determine the sociodemographic characteristics of the Ophthalmology Outpatient Clinic at the Royal Adelaide Hospital, to ascertain satisfaction levels with aspects of care, and determine if patient satisfaction levels can be increased by the provision of information letters prior to appointment. METHODS: New patients attending Ophthalmology Outpatient Clinic were surveyed regarding sociodemographic information and satisfaction levels. Participants received an introductory letter prior to their clinic appointment, and were compared with controls. Responses were analysed using Mann-Whitney U-tests. Satisfaction scores regarding waiting times, clinic environment, doctors, nurses, clerical staff and general satisfaction were correlated with demographic data using Spearman correlation coefficient analysis and chi-squared statistics. Ordinal logistic regression and non-parametric rack testing determined differences between the two groups. RESULTS: Positive correlations were identified between patient-estimated actual waiting time, ratings of waiting times, booking efficiency, information given, intention to return to, recommend the clinic, to comply with advice given, and higher ratings of the overall quality of the service, and satisfaction levels. Negative qualitative comments correlated with lower ratings of satisfaction and quality of the service. The intervention group showed statistically significantly higher ratings of the wait in clinic and the overall quality of the service. Satisfaction ratings of the clinic staff were also higher in the intervention group. CONCLUSIONS: Ophthalmology outpatients are more likely to be happy with their health care if they are satisfied with waiting times, and are more likely to return to the service and comply with advice, thus improving health outcomes. Provision of information regarding the outpatient clinic structure and estimated waiting times is a simple, cost-effective method of improving patient satisfaction levels and altering perceptions of waiting times.