Bilateral Blindness Research Articles

Prevalence and Causes of Unilateral Vision Impairment and Unilateral Blindness in Australia

This study determines the prevalence of unilateral vision impairment (VI) and unilateral blindness to assist in policy formulation for eye health care services. To determine the prevalence and causes of unilateral VI and unilateral blindness in Australia. This cross-sectional population-based survey was conducted from March 2015 to April 2016 at 30 randomly selected sites across all strata of geographic remoteness in Australia. A total of 1738 indigenous Australians 40 years or older and 3098 nonindigenous Australians 50 years or older were included. The prevalence and causes of unilateral vision impairment and blindness, defined as presenting visual acuity worse than 6/12 and 6/60, respectively, in the worse eye, and 6/12 or better in the better eye. Of the 1738 indigenous Australians, mean (SD) age was 55.0 (10.0) years, and 1024 participants (58.9%) were female. Among the 3098 nonindigenous Australians, mean (SD) age was 66.6 (9.7) years, and 1661 participants (53.6%) were female. The weighted prevalence of unilateral VI in indigenous Australians was 12.5% (95% CI, 11.0%-14.2%) and the prevalence of unilateral blindness was 2.4% (95% CI, 1.7%-3.3%), respectively. In nonindigenous Australians, the prevalence of unilateral VI was 14.6% (95% CI, 13.1%-16.3%) and unilateral blindness was found in 1.4% (95% CI, 1.0%-1.8%). The age-adjusted and sex-adjusted prevalence of unilateral vision loss was higher in indigenous Australians than nonindigenous Australians (VI: 18.7% vs 14.5%; P = .02; blindness: 2.9% vs 1.3%; P = .02). Risk factors for unilateral vision loss included older age (odds ratio [OR], 1.60 for each decade of age for indigenous Australians; 95% CI, 1.39-1.86; OR, 1.65 per decade for nonindigenous Australians; 95% CI, 1.38-1.96), very remote residence (OR, 1.65; 95% CI, 1.01-2.74) and self-reported diabetes (OR, 1.52; 95% CI, 1.12-2.07) for indigenous Australians, and having not undergone an eye examination in the past 2 years for nonindigenous Australians (OR, 1.54; 95% CI, 1.04-2.27). Uncorrected refractive error and cataract were leading causes of unilateral VI in both populations (70%-75%). Corneal pathology (16.7%) and cataract (13.9%) were leading causes of unilateral blindness in indigenous Australians, while amblyopia (18.8%), trauma (16.7%), and age-related macular degeneration (10.4%) were major causes of unilateral blindness in nonindigenous Australians. Unilateral vision loss is prevalent in indigenous and nonindigenous Australians; however, most cases are avoidable. As those with unilateral vision loss caused by cataract and posterior segment diseases may be at great risk of progressing to bilateral blindness, national blindness prevention programs may benefit from prioritizing examination and treatment of those with unilateral vision loss.

Prevalence and Causes of Visual Impairment in Adults in Binhu District, Wuxi, China

BackgroundPreviously reported data has guided the treatment and prevention of blindness. This study aimed to evaluate the current prevalence and causes of visual impairment among adults who were 50 years old and older in the Binhu District of Wuxi City, China.Material/MethodsA randomized sample of stratified clusters was used to analyze individuals from 30 basic sampling units in Wuxi Binhu District. Visual impairment was defined according to World Health Organization (WHO) standards.ResultsA total of 6725 people who were at least 50 years old participated in this study. According to WHO standards, bilateral low vision and blindness prevalence were both higher in women than in men (low vision: 6.5% vs. 5.2%; and blindness: 1.4% vs. 0.8%; P=0.022 and P=0.039, respectively). The incidence of bilateral visual impairment increased significantly with age (P<0.001 and P<0.001, respectively). Further studies showed that the main causes of bilateral low vision were cataract, high myopic macular degeneration (MMD), and age-related macular degeneration (AMD). The main causes of bilateral blindness were cataract, MMD, and eye loss/atrophy, while the main causes of monocular low vision were cataract, MD, and AMD. The main causes of monocular blindness were cataract, eye loss/atrophy, and AMD.ConclusionsThe prevalence of low vision and blindness remains high in the Binhu District of Wuxi City in China, especially among older women. In our study, cataracts were the leading cause of visual impairment. Our study highlights that some efforts should be initiated to prevent and treat blindness and low vision. Additional causes of visual impairment were MMD, AMD, and eye loss/atrophy.

Bilateral cortical blindness with Anton–Babinski syndrome in an elderly Nigerian woman: Challenges for tertiary prevention

Anton–Babinski syndrome (Anton's syndrome) is well described in the scientific literature even though it is a rare neurological condition. Most publications have highlighted the anatomy, neurophysiology, and pathology of visual anosognosia, which is the hallmark of the syndrome. We are not aware of any published report of cortical blindness with Anton's syndrome from Africa. We report a catastrophic complication of severe hypertension in an elderly Nigerian woman who was on follow-up for stroke, chronic heart failure, diabetes mellitus, and glaucoma. She developed bilateral cortical blindness with Anton's syndrome as a complication of severe hypertension, following 3 weeks of missed medications. This report highlights some challenges of tertiary prevention in this elderly woman without health insurance, who before becoming blind, had been largely dependent on family members' goodwill for her medical care.

Bone morphogenetic protein signaling: a promising target for white matter protection in perinatal brain injury.

Bone morphogenetic protein signaling: a promising target for white matter protection in perinatal brain injury.

Epileptic seizure: An unusual presentation of takayasu arteritis

Background: Takayasu arteritis is a vasculitic disease involving major arteries. It commonly presented with constitutional symptoms. Neurological manifestations such as headache, transient ischemic attack, stroke, vertigo, dementia, confusion, hypertensive encephalopathy and bilateral blindness can be the presenting features rarely. Takayasu arteritis presenting as epileptic seizure is extremely rare. We report a 32 years old previously healthy lady presented with a history of generalized tonic clonic seizure associated with loss of consciousness and ultimately found to have takayasu arteritis and manage with steroids successfully without antiepileptic drugs.

Posterior reversible encephalopathy syndrome presenting as bilateral blindness in a post partum female

Posterior reversible encephalopathy syndrome PRES previously is an europhthalmic disorder characterized by painless loss of vision seizures headache and altered mental status and is associated with white matter vasogenic edema predominantly affecting the occipital and parietal lobes of the brain It has several etiologies but one of the most common includes eclampsia This case report describes a rare scenario where a patient presented with complete bilateral loss of vision due to PRES syndrome She was days postpartum and had undergone caesarian section for pre eclampsia Her condition recovered completely with treatment within a week of presentation

Keratoprosthesis: Current global scenario and a broad Indian perspective.

Keratoprosthesis (Kpro) forms the last resort for bilateral end-stage corneal blindness. The Boston Type 1 and 2 Kpros, the modified osteo-odonto Kpro and the osteo-Kpro are the more frequently and commonly performed Kpros, and this review attempts to compile the current data available on these Kpros worldwide from large single-center studies and compare the indications and outcomes with Kpros in the Indian scenario. Although the indications have significantly expanded over the years and the complications have reduced with modifications in design and postoperative regimen, these are procedures that require an exclusive setup, and a commitment toward long-term follow-up and post-Kpro care. The last decade has seen a surge in the number of Kpro procedures performed worldwide as well as in India. There is a growing need in our country among ophthalmologists to be aware of the indications for Kpro to facilitate appropriate referral as well as of the procedure to enable basic evaluation during follow-ups in case the need arises, and among corneal specialists interested to pursue the field of Kpros in understanding the nuances of these surgeries and to make a judicious decision regarding patient and Kpro selection and more importantly deferral.

Magnitude of visual impairment, blindness and causes in the southwest region of São Paulo state, Brazil.

The purpose of this study was to evaluate the magnitude and determinants of bilateral blindness and visual impairment (VI) in the southwest region of São Paulo State, Brazil. This cross-sectional study conducted during 2013 and 2014 targeted people of all ages in 10 districts in the southwest region of São Paulo State, Brazil. Ophthalmologists in a mobile unit measured visual acuity and examined eyes. Visual acuity was categorized according to the World Health Organization sex-adjusted rates with 95% confidence intervals (CI) were calculated. Number of blindness and visually impaired was projected for the entire study area. We examined 2,306 participants. The age- and sex-adjusted frequency of bilateral blindness was 0.26% (95% CI: 0.1-0.4). Females (0.35%) and patients 350 years old (0.58%) had higher rate of blindness compared with males and younger individuals. The rate of severe VI was 9.1% (95% CI: 8.8-10.6) and was higher among males (11.6%) and those 350 years (12.3%). There could be 880 people with bilateral SVI in the study area. Bilateral severe VI was attributed to cataracts in 63% and was attributed to refractive error in 18%. Visual impairment and blindness in the study population was low and mainly due to cataract and refractive errors. Initiatives should be addressed by health care services to further reduce avoidable blindness in the region.

Bilateral irreversible visual loss due to arteritic anterior optic ischemic neuropathy

Introduction: Anterior optic ischemic neuropathy (AOIN) is the most frequent cause of visual loss in giant cell arteritis (GCA). As blindness is rarely reversible, the main therapeutic goal is to prevent bilateral disease by immediate initiation of high-dose intravenous steroids. Approximately, one third of patients present with bilateral visual impairment. Case Report: A 77-year-old patient, came to the Ophthalmology Emergency Room for sudden loss of vision in the left eye (OS) to no light perception (NLP) with two days duration and significant narrowing of the visual field in the right eye (OD) with 10 hours duration. Fundus examination revealed swelling and pallor of the optic disc in both eyes (OU). Laboratory examination showed elevated ESR (56 mm/h) and CRP (5.24 mg/dl). Temporal artery biopsy (TAB) proved granulomas and fibrosis within the vessel wall. Immediate Methylprednisolon 1gm was administered intravenously for five days, followed by oral Prednisone 1mg/kg for four weeks with tapering of 10 mg per month. The patient was put on diabetic and low sodium regimen. During the 3rd day of treatment, vision OD dropped to NLP. Despite continuing systemic steroid therapy, vision remained unchanged. Two months following discharge, the patient died from myocardial infarction. Conclusion: Irreversible bilateral blindness occurred in a patient with arteritic AOIN, while he was on systemic steroids, probably due to late presentation, when vision was already affected bilaterally.

Hereditary microphthalmia in Texel lambs in Brazil

On a farm in southern Brazil, four lambs in a flock of 300 Texel sheep were born with bilateral blindness. They revealed bilateral occlusion of the eyelids and were unresponsive to external visual stimuli and were disoriented when walking. A post-mortem examination revealed bilateral occlusion of the eyelids and, microscopically, total or partial absence of the lens was observed. Blood samples from 20% of the herd (61/300) were sent for molecular analysis. The four affected lambs were homozygous (C/C) for a mutation (single-nucleotide polymorphism c.338G > C) in the PITX3 gene, and 26.2% (16/61) of the herd, including the two ewe and two ram parents, were heterozygous (G/C). Based on clinical, pathological and molecular analysis, it was possible to determine the existence of hereditary microphthalmia in Texel lambs associated with the c.338G > C SNP in the PITX3 gene for the first time in Brazil. The result of this study provides a warning to veterinarians and breeders, emphasizing the importance of considering this disease in the differential diagnosis of congenital diseases in the Brazilian Texel flock.

Large mucocele with intracranial and intraorbital extension

Case summary A 26-year-old female had had progressive right eye blindness for 13 years. She did not have any other complaints such as headache, seizure, or weakness. At that time she was admitted to a local hospital and Computed tomography (CT) imaging was performed, showing a mass at left maxillary sinus with extracranial extension. The caring physician advised surgery but her family refused due to financial problem. A year later, she developed complete bilateral eye blindness and the subsequent CT revealed larger size of the mass. She was referred to a tertiary hospital for surgery but she lost follow-up. In this visit, she had foul-smelling discharge per left nostril without fever for 2 weeks followed by seizure and headache for 2 days. She had no underlying disease, no history of seizure and head trauma. Physical examination revealed that her vital signs were normal; body temperature of 36.7*c, blood pressure of 100/69 mmHg, pulse rate of 110/ minute, and respiratory rate of 24/ minute. Both pupils were dilated (8 mm/ 8 mm). Light reflexes were diminished in both eyes as well as proptosis with more severity in the left eye. The fundus scope showed bilateral markedly pale discs. There was a mass protruding outside both nostrils. The cranial nerve examination and neurological examinations were normal. Laboratory investigation for hormonal levels (Free-T4, TSH, HGH cortisol, FSH, LH, prolactin) were all in normal ranges.Thanatta Seemai, M.D.From The Department of Radiology, Faculty of Medicine,Prince of Songkla University, Songkhla, ThailandAddress correspondence T.S.(e-mail:thanatta.seemai@gmail.com)

Willingness to pay for cataract surgery is much lower than actual costs in Zamfara state, northern Nigeria

ABSTRACTPurpose: Direct medical and non-medical costs incurred by those undergoing subsidised cataract surgery at Gusau eye clinic, Zamfara state, were recently determined. The aim of this study was to assess the willingness to pay for cataract surgery among adults with severe visual impairment or blindness from cataract in rural Zamfara and to compare this to actual costs.Methods: In three rural villages served by Gusau eye clinic, key informants helped identify 80 adults with bilateral severe visual impairment or blindness (<6/60), with cataract being the cause in at least one eye. The median amount participants were willing to pay for cataract surgery was determined. The proportion willing to pay actual costs of the (i) subsidised surgical fee (US$18.5), (ii) average non-medical expenses (US$25.2), and (iii) average total expenses (US$51.2) at Gusau eye clinic were calculated. Where participants would seek funds for surgery was determined.Results: Among 80 participants (38% women), most (n = 73, 91%) were willing to pay something, ranging from <US$1 to US$186 (median US$18.5, interquartile range 6.2–31.1). Approximately half of the participants (n = 41) were willing to pay US$18.5 (78% men), one-third (n = 26) were willing to pay US$25.2 (77% men); and 11% (n = 9) were willing to pay US$51.2 (all men). Only six participants (8%) already had the money to pay; one quarter (n = 20) would need to sell possessions to raise the funds.Conclusion: Willingness to pay for cataract surgery among adults with operable cataract in rural Zamfara state is far lower than current costs of undergoing surgery. People who were widowed—most of whom were women—were willing to pay least. Further financial support is required for cataract surgery to be universally accessible.

Resolution of Anton–Babinski syndrome after systemic thrombolysis and mechanical thrombectomy with a stentriever

Anton–Babinski syndrome is a rare neuropsychiatric syndrome characterized by bilateral cortical blindness and anosognosia with visual confabulation. We present the case of a patient presenting with occlusion of both posterior cerebral arteries (PCA), with Anton–Babinski syndrome, completely solved after combined systemic thrombolysis and mechanical thrombectomy with a stent-retriever.

Prevalence of blindness and cataract surgical coverage in Narayani Zone, Nepal: a rapid assessment of avoidable blindness (RAAB) study

BackgroundThe 1981 Nepal Blindness Survey first identified the Narayani Zone as one of the regions with the highest prevalence of blindness in the country. Subseuqently, a 2006 survey of the...

Severe neurodevelopmental disability and healthcare needs among survivors of medical and surgical necrotizing enterocolitis: A prospective cohort study

PurposeThis study characterizes neurodevelopmental outcomes and healthcare needs of extremely low birth weight (ELBW) survivors of necrotizing enterocolitis (NEC) compared to ELBW infants without NEC. MethodsData were collected prospectively on neonates born 22–27weeks’ gestation or 401–1000g at 47 Vermont Oxford Network member centers from 1999 to 2012. Detailed neurodevelopmental evaluations were conducted at 18–24months corrected age. Information regarding rehospitalizations, postdischarge surgeries, and feeding was also collected. “Severe neurodevelopmental disability” was defined as: bilateral blindness, hearing impairment requiring amplification, inability to walk 10 steps with support, cerebral palsy, and/or Bayley Mental or Psychomotor Developmental Index <70. Diagnosis of NEC required both clinical and radiographic findings. ResultsThere were 9063 children without NEC, 417 with medical NEC, and 449 with surgical NEC evaluated. Significantly higher rates of morbidity were observed among infants with a history of NEC. Those with surgical NEC were more frequently affected across all outcome measures at 18–24months corrected age: 38% demonstrated severe neurodevelopmental disability, nearly half underwent postdischarge operations, and a quarter required tube feeding at home. ConclusionAt 18–24months, extremely low birth weight survivors of necrotizing enterocolitis were at markedly increased risk (p<0.001) for severe neurodevelopmental disability, postdischarge surgery, and tube feeding. Level of evidenceII (prospective cohort study with <80% follow-up rate).

Affective blindsight relies on low spatial frequencies

The human brain can process facial expressions of emotions rapidly and without awareness. Several studies in patients with damage to their primary visual cortices have shown that they may be able to guess the emotional expression on a face despite their cortical blindness. This non-conscious processing, called affective blindsight, may arise through an intact subcortical visual route that leads from the superior colliculus to the pulvinar, and thence to the amygdala. This pathway is thought to process the crude visual information conveyed by the low spatial frequencies of the stimuli.In order to investigate whether this is the case, we studied a patient (TN) with bilateral cortical blindness and affective blindsight. An fMRI paradigm was performed in which fearful and neutral expressions were presented using faces that were either unfiltered, or filtered to remove high or low spatial frequencies. Unfiltered fearful faces produced right amygdala activation although the patient was unaware of the presence of the stimuli. More importantly, the low spatial frequency components of fearful faces continued to produce right amygdala activity while the high spatial frequency components did not. Our findings thus confirm that the visual information present in the low spatial frequencies is sufficient to produce affective blindsight, further suggesting that its existence could rely on the subcortical colliculo-pulvino-amygdalar pathway.

Impact of type I Boston keratoprosthesis implantation on vision-related quality of life

AimTo determine the impact of type I Boston keratoprosthesis (KPro) implantation on vision-related quality of life (VRQoL).MethodsProspective study in 33 patients (mean age 56±12 years, 67% male) with bilateral corneal...

Prevalence and causes of low vision and blindness in a Chinese population with type 2 diabetes: the Dongguan Eye Study

To assess the prevalence and causes of low vision and blindness in type 2 diabetes patients, a population-based cross-sectional study including 8952 rural-dwelling residents aged 40 years or older from Hengli Town in Southern China was conducted. Participants underwent standard interviews, physical measurements, laboratory tests, and comprehensive eye examinations. Low vision and blindness were defined based on WHO criteria. Visual acuity data were available for 1348 (89.9%) of the 1500 subjects with type 2 diabetes. Age-standardized prevalence of bilateral low vision and blindness assessed in the better-seeing eye was 2.9% (95% confidence interval [CI]: 2.0–3.8) and 0.7% (95% CI: 0.2–1.1) based on best-corrected visual acuity (BCVA). Cataracts were the primary cause of low vision and blindness. Visual impairment was associated with age (odds ratio [OR]: 3.73, 95% CI: 2.39–5.83), education level (OR: 3.21, 95% CI: 1.63–6.29), duration of diabetes (OR: 1.14, 95% CI: 1.04–1.25) and body mass index (OR: 0.86, 95% CI: 0.77–0.95). Our data suggest that approximately 70% of visual impairment in this diabetic population could be eliminated with appropriate cataract surgery or spectacle correction. Greater consideration should be given to older type 2 diabetes patients with a level of lower education.

Visual impairment and blindness in Hungary.

The aim of this study was to estimate the prevalence and causes of blindness, severe visual impairment (SVI), moderate visual impairment (MVI), and early visual impairment (EVI) and its causes in an established market economy of Europe. A cross-sectional population-based survey. A sample size of 3675 was calculated using the standard Rapid Assessment of Avoidable Blindness (RAAB) software in Hungary. A total of 105 clusters of 35 people aged 50years or older were randomly selected with probability proportionate to size by the Hungarian Central Statistical Office. Households within the clusters were selected using compact segment sampling. Visual acuity (VA) was assessed with a Snellen tumbling E-chart with or without a pinhole in the households. The adjusted prevalences of bilateral blindness, SVI, MVI and EVI were 0.9% (95% CI: 0.6-1.2), 0.5% (95% CI: 0.2-0.7), 5.1% (95% CI: 4.3-5.9) and 6.9% (95% CI: 5.9-7.9), respectively. The major causes of blindness in Hungary were age-related macular degeneration (AMD; 27.3%) and other posterior segment diseases (27.3%), cataract (21.2%) and glaucoma (12.1%). Cataract was the main cause of SVI, MVI and EVI. Cataract surgical coverage (CSC) was 90.7%. Of all bilateral blindness in Hungary, 45.5% was considered avoidable. This study proved that RAAB methodology can be successfully conducted in industrialized countries, which often lack reliable epidemiologic data. The prevalence of blindness was relatively low, with AMD and other posterior segment diseases being the leading causes, and cataract is still a significant cause of visual impairment.

Changing patterns of cataract services in North-West Nigeria: 2005-2016.

PurposeThis study was conducted to assess the impact of the eye care programme on cataract blindness and cataract surgical services in Sokoto, Nigeria over a 12 year period 2005–2016.MethodsData from the 2005 population based cross-sectional study of blindness in Sokoto state was re-analysed to obtain baseline estimates of the prevalence of cataract blindness and cataract surgical coverage for persons 50 years and over in Wurno health zone. A population based survey of a representative sample of persons 50 years and over in Wurno health zone was conducted in July 2016. Data on eye health workforce, infrastructure and cataract surgical services between 2005 and 2016 were analysed from relevant documents.ResultsIn 2005 the unadjusted prevalence of bilateral cataract blindness (<3/60) in people 50 years and over in Wurno health zone was 5.6% (95% CI: 3.1, 10.1). By 2016 this had fallen to 2.1% (95% CI 1.5%, 2.7%), with the age-sex adjusted prevalence being 1.9% (95% CI 1.3%, 2.5%). The CSC for persons with visual acuity <3/60, <6/60, <6/18 for Wurno health zone was 9.1%, 7.1% and 5.5% respectively in 2005 and this had increased to 67.3%, 62.1% and 34.7% respectively in 2016. The CSR in Sokoto state increased from 272 (1005 operations) in 2006, to 596 (2799 operations) in 2014. In the 2005 survey, couching (a procedure used by traditional practitioners to dislocate the lens into the vitreous cavity) accounted for 87.5% of all cataract interventions, compared to 45.8% in the 2016 survey participants. In 2016 18% of eyes having a cataract operation with IOL implantation had a presenting visual acuity of <6/60 (poor outcome) with the main causes being postoperative complications (53%) and uncorrected refractive error (29%).ConclusionBetween 2005 and 2016 there was a doubling in cataract surgical rate, a 7 times increase in cataract surgical coverage (<3/60), and a decrease in cataract blindness and the proportion of eyes being couched. However, there remains a high prevalence of un-operated cataract in 2016 indicating a need to further improve access to affordable and good quality cataract surgical services.