Blindness and Visual Impairment Profile and Rapid Assessment of Avoidable Blindness in South East Asia: Analysis of New Data. 2017 APAO Holmes Lecture

PURPOSE

The International Agency for Prevention of Blindness (IAPB) South East Asia region (SEAR) that consists of 11 countries contains 26% of the world's population (1,761,000,000). In this region 12 million are blind and 78.5 million are visually impaired. This amounts to 30% of global blindness and 32% of global visual impairment.

DESIGN

Rapid assessment of avoidable blindness (RAAB) survey analysis.

METHODS

RAAB, either a repeat or a first time survey, was completed in 8 countries in this decade (2010 onwards). These include Bangladesh, Bhutan, India, Indonesia, Maldives, Sri Lanka, Thailand, and Timor Leste.

RESULTS

Cataract is the principal cause of blindness and severe visual impairment in all countries. Refractive error is the principal cause of moderate visual impairment in 4 countries: Bangladesh, India, Maldives, and Sri Lanka; cataract continues to be the principal cause of moderate visual impairment in 4 other countries: Bhutan, Indonesia, Thailand, and Timor Leste. Outcome of cataract surgery is suboptimal in the Maldives and Timor Leste.

CONCLUSIONS

Rigorous focus is necessary to improve cataract surgery outcomes and correction of refractive error without neglecting the quality of care. At the same time allowances must be made for care of the emerging causes of visual impairment and blindness such as glaucoma and posterior segment disorders, particularly diabetic retinopathy.

Retinal Prosthesis System for Advanced Retinitis Pigmentosa: A Health Technology Assessment Update

BACKGROUND

Retinitis pigmentosa is a group of inherited disorders characterized by the degeneration of the photoreceptors in the retina, resulting in progressive vision loss. The Argus II system is designed to restore partial functional vision in patients with profound vision loss from advanced retinitis pigmentosa. At present, it is the only treatment option approved by Health Canada for this patient population. In June 2016, Health Quality Ontario published a health technology assessment of the Argus II retinal prosthesis system for patients with advanced retinitis pigmentosa. Based on that assessment, the Ontario Health Technology Advisory Committee recommended against publicly funding the Argus II system for this population. It also recommended that Health Quality Ontario re-evaluate the evidence in 1 year. The objective of this report was to examine new evidence published since the 2016 health technology assessment.

METHODS

We completed a health technology assessment, which included an evaluation of clinical benefits and harms, value for money, and patient preferences related to the Argus II system. We performed a systematic literature search for studies published since the 2016 Argus II health technology assessment. We developed a Markov decision-analytic model to assess the cost-effectiveness of the Argus II system compared with standard care, and we calculated incremental cost-effectiveness ratios over a 20-year time horizon. We also conducted a five-year budget impact analysis. Finally, we interviewed people with retinitis pigmentosa about their lived experience with vision loss, and with the Argus II system.

RESULTS

Four publications from one multicentre international study were included in the clinical review. Patients showed significant improvements in visual function and functional outcomes with the Argus II system, and these outcomes were sustained up to a 5-year follow-up (moderate quality of evidence). The safety profile was generally acceptable.In the base case economic analysis, the Argus II system was cost-effective compared with standard care if the willingness to pay was more than $97,429 per quality-adjusted life-year. We estimated that funding the Argus II system would cost the province $0.71 to $0.78 million per year over 5 years, assuming 4 implants per year.People with lived experience spoke about the challenges of retinitis pigmentosa, including the gradual but persistent progression of the disease; its impact on their quality of life and their families; and the accessibility challenges they faced. Those who used the Argus II system spoke about its positive impact on their quality of life.

CONCLUSIONS

Based on evidence of moderate quality, the Argus II retinal prosthesis system improved visual function, real-life functional outcomes, and quality of life in patients with advanced retinitis pigmentosa. The Argus II system is expensive, but the cost to publicly fund it would be low, because of the small number of eligible patients. The Argus II system can only enable perception of light/dark and shapes/objects, but these advancements represent important gains for people with retinitis pigmentosa in terms of mobility and quality of life.

Time to development of ocular syphilis after syphilis infection

To provide an estimate of the incubation period of ocular syphilis based on serology using both clinical data and stored serum samples, we retrospectively reviewed patients with HIV-1 infection who presented with ocular syphilis between August 1997 and July 2015 in a tertiary hospital in Japan. The incubation period of ocular syphilis was defined as the time from syphilis infection to the development of ocular symptoms due to ocular syphilis. During the study period, 20 patients were diagnosed with ocular syphilis and 8 patients were enrolled in the present study. All patients were Japanese men who have sex with men with a median age of 46 years (IQR 41.5-53.5). The median CD4 count was 668.5/μL (IQR 567.8-734.3) and 5 of the 8 patients had HIV-1 viral load of less than 50 copies/mL. All study patients presented to our clinic because of the development of ocular symptoms, and they did not have any other symptoms compatible with primary, secondary, or tertiary syphilis. The median time between syphilis infection and development of ocular symptoms was 11 months (IQR 4-19, range 2.5-45). Seven out of eight (87.5%) cases developed ocular syphilis within 2 years of syphilis infection. Ocular syphilis should be suspected even in patients with early syphilis who present with ocular symptoms. Moreover, routine serologic screening for syphilis among patients with HIV-1 infection is critical for prevention of irreversible visual loss in ocular syphilis cases.

The Global Issue of Vision Loss and What We Can Do About It: José Rizal Medal 2015

The prevalence of blindness increases rapidly with increasing age. Globally, there are some 32 million people who are blind and 191 million with poor vision. The leading cause of blindness worldwide is cataract, whereas uncorrected refractive error causes most poor vision. The rates of blindness from diabetes and macular degeneration are rapidly increasing, and age-related macular degeneration is the leading cause of blindness in developed countries. Three quarters of this blindness can be prevented or treated, and although the absolute number of blind people increased slightly between 1990 and 2010, very importantly, the prevalence of blindness has been halved as eye care programs and particularly cataract services have developed. We know how to deliver better eye care, and it works! However, with only 205,000 ophthalmologists worldwide, there is much work to do. The International Council of Ophthalmology has a major focus on education and team building to improve the quality and availability of eye care around the world. Its programs include curricula for all levels, examinations, fellowships, teaching of teachers, continuing professional development, and of course, the World Ophthalmology Congresses. We must work together in partnership to eliminate avoidable blindness worldwide.

Functional low vision in adults from Latin America: findings from population-based surveys in 15 countries

OBJECTIVE

To review data on functional low vision (FLV) (low vision-visual acuity (VA) < 6/18 (<20/60) to > perception of light (PL+) in the better eye-that is untreatable and uncorrectable) in adults aged 50 years or older from published population-based surveys from 15 countries in Latin America and the Caribbean.

METHODS

Data from 15 cross-sectional, population-based surveys on blindness and visual impairment (10 national and five subnational) covering 55 643 people > 50 years old in 15 countries from 2003 to 2013 were reanalyzed to extract statistics on FLV. Eleven of the studies used the rapid assessment of avoidable blindness (RAAB) method and four used the rapid assessment of cataract surgical services (RACSS) method. For the 10 national surveys, age-and sex-specific prevalence of FLV was extrapolated against the corresponding population to estimate the total number of people > 50 years old with FLV.

RESULTS

Age- and sex-adjusted prevalence of FLV in people > 50 years old ranged from 0.9% (Guatemala, Mexico, and Uruguay) to 2.2% (Brazil and Cuba) and increased by age. The weighted average prevalence for the 10 national surveys was 1.6%: 1.4% in men and 1.8% in women. For all 10 national studies, a total of 509 164 people > 50 years old were estimated to have FLV. Based on the 910 individuals affected, the main causes of FLV were age-related macular degeneration (weighted average prevalence of 26%), glaucoma (23%), diabetic retinopathy (19%), other posterior segment disease (15%), non-trachomatous corneal opacities (7%), and complications after cataract surgery (4%).

CONCLUSIONS

FLV is expected to rise because of 1) the exponential increase of this condition by age, 2) increased life expectancy, and 3) the increase in people > 50 years old. These data can be helpful in planning and developing low vision services for the region; large countries such as Brazil and Mexico would need more studies. Prevention is a major strategy to reduce FLV, as more than 50% of it is preventable.

Congenital Cataract: Progress in Surgical Treatment and Postoperative Recovery of Visual Function

Congenital cataract is a common cause of childhood low vision or blindness worldwide. Early surgery should be performed in sensitive vision development period to avoid vision deprivation in cases of strabismus and nystagmus development. Postoperative recovery of visual function is of great significance for these patients and should include proper postoperative aphakia correction by the application of a contact lens and secondary implantation of an intraocular lens (IOL). Patients should receive amblyopic training after surgery to improve their postoperative visual acuity. Although recent advances in surgery techniques and materials have brought better postoperative visual acuity and less complications, a few postoperative complications can still hamper vision condition and vision development, including posterior capsule opacification and secondary glaucoma. Surgery in early infancy are risk factors for these two complications. Life-long follow-up is essential for these patients. Further study will continue to address the surgery timing issue and methods that prevent postoperative complications.

Is binocular vision worth considering in people with low vision?

In someone with good vision, binocular vision provides benefits which could not be obtained by monocular viewing only. People with visual impairment often have abnormal binocularity. However, they often use both eyes simultaneously in their everyday activities. Much remains to be known about binocular vision in people with visual impairment. As the binocular status of people with low vision strongly influences their treatment and rehabilitation, it should be evaluated and considered before diagnosis and further recommendations.

[Integrated therapy of congenital cataract to prevent blindness and low vision]

Congenital cataract is a major cause of treatable blindness in the pediatric population worldwide. Advances in microsurgical techniques have significantly increased the success rate of surgery. However, visual rehabilitation outcomes are not always satisfactory even after a successful surgery. Due to delayed surgery, irrational aphakic correction, and lack of amblyopic training, a large number of infants in China remain blind or low-visioned after cataract surgery. Appropriate timing of surgical intervention, rational surgical methodology as well as systematic optical correction and amblyopic training are critical for the prevention of blindness and low vision in congenital cataract.

[Prevention of blindness is still an arduous task and embarks on a long road in China]

The outcomes from China Nine-Province Survey shows that the prevention of blindness in China have got some achievements, however, the status of blindness and moderate and severe visual impairment is still serious. The prevalence of blindness and moderate and severe visual impairment in some remote areas is higher than the national average level. The major cause of blindness and visual impairment is cataract,however, retinal diseases are found to be the second major cause, which reflects both characteristics of blindness in the developed and developing countries. The prevalence of blindness and moderate and severe visual impairment are 1.93% and 5.31% respectively, however, the cataract surgery coverage rate is only 35.7%. These figures shows that prevention of blindness is still an arduous task and embark on a long road in China. The priority for prevention of blindness should be cataract-related blindness and visual impairment at present. Meanwhile, we should begin to conduct the prevention of the retinal diseases.

The peculiar challenges of blindness prevention in Nigeria: a review article

AIM

To describe the challenges peculiar to Nigeria in the implementation of vision 2020: the right to sight and to proffer solutions as to the way forward

METHOD

A review of the recently completed national blindness survey, current literature, and the advocacy experience of the Ophthalmological Society of Nigeria.

FINDINGS

The prevalence of blindness in Nigeria is 0.78%. Over 43% of these are blind from cataracts and a further 9% from uncorrected aphakia or complications of couching. 50% of all cataract interventions are carried out by itinerant couchers. Other major causes of blindness are glaucoma (16%) corneal opacities (12%), trachoma (4%), optic atrophy (3%) onchocerciasis (1%) and macular disease (1%). 70% of these are either preventable or reversible. Nigeria has a relatively favourable ophthalmologist/population ratio of about 2.8 per million, but has a low Cataract surgical rate of 300 per million per year. The reasons for this include a lack of ownership of blindness prevention programs, a lack of political will and parlous state of funding for vision 2020. There is an abdication of responsibility for both training and services on the part of government to the International NonGovernmental organisations. Teaching hospitals no longer generate enough patient surgical load to support training. We estimate it would cost N8.5 billion ($56.8 million) to sustain the WHO recommended Cataract Surgical Rate of 3000 per million per year in Nigeria.

CONCLUSIONS

Nigeria is not headed in the direction of meeting Vision 2020 targets. Advocacy involving funding through the MDGs, needs to be intensified.

[To promote "Vision 2020" Initiative under the new situation in China]

At present, the prevention of blindness in China is in the favorable period and got some important progress. Recent five years, Chinese government conducted a series of the program for prevention of blindness, cataract surgical rate is increasing. The reform of the medical system conducted by the government is favorable to the prevention of blindness. There have been better situation and enough technique and personnel to conduct cataract surgery. However, prevention of blindness is still a big challenge to Chinese ophthalmological society. Blindness and visual impairment is still a major public health problem in China. The cataract surgical rate is still quite low. Thus, Chinese ophthalmologists should further promote "Vision 2020" Initiative and prevention of blindness in China. They should further recognize the significance for prevention of blindness, strength the construction of the system for prevention of blindness and eye care, actively prevent and control the eye diseases and conduct the research work in the prevention of blindness.

[Sampling and measurement methods of the protocol design of the China Nine-Province Survey for blindness, visual impairment and cataract surgery]

OBJECTIVE

To design the protocol of the China nine-province survey for blindness, visual impairment and cataract surgery to evaluate the prevalence and main causes of blindness and visual impairment, and the prevalence and outcomes of the cataract surgery.

METHODS

The protocol design was began after accepting the task for the national survey for blindness, visual impairment and cataract surgery from the Department of Medicine, Ministry of Health, China, in November, 2005. The protocol in Beijing Shunyi Eye Study in 1996 and Guangdong Doumen County Eye Study in 1997, both supported by World Health Organization, was taken as the basis for the protocol design. The relative experts were invited to discuss and prove the draft protocol. An international advisor committee was established to examine and approve the draft protocol. Finally, the survey protocol was checked and approved by the Department of Medicine, Ministry of Health, China and Prevention Program of Blindness and Deafness, WHO.

RESULTS

The survey protocol was designed according to the characteristics and the scale of the survey. The contents of the protocol included determination of target population and survey sites, calculation of the sample size, design of the random sampling, composition and organization of the survey teams, determination of the examinee, the flowchart of the field work, survey items and methods, diagnostic criteria of blindness and moderate and sever visual impairment, the measures of the quality control, the methods of the data management.

CONCLUSION

The designed protocol became the standard and practical protocol for the survey to evaluate the prevalence and main causes of blindness and visual impairment, and the prevalence and outcomes of the cataract surgery.

Implications for postoperative visual loss: steep trendelenburg position and effects on intraocular pressure

Postoperative visual loss (POVL) is a rare but catastrophic complication after nonocular surgery. Previously POVL has been reported in lengthy, prone, lateral, or cardiopulmonary cases, with extreme blood loss, hemodilution, and hypotension. The author's index case of POVL following a lengthy operation in steep Trendelenburg position (ST) prompted study of the relationship between intraocular pressure (IOP), mean arterial pressure (MAP), and time spent in ST. A 3-year investigation of the relationship between IOP and ST procedures is reported. Ocular perfusion pressure (OPP) was calculated from IOP and MAP in supine position and at 30-minute intervals during ST. At start of surgery, IOP of 37 patients ranged from 9 to 28 mm Hg. At 120 minutes, IOP ranged from 25 to 54 mm Hg. The OPP ranged from 50 to 82 mm Hg at start of surgery and from 21 to 75 mm Hg after 120 minutes. Increased IOP and reductions in OPP in relationship to position change were statistically significant (P < .001), with OPP falling below IOP in 10 cases. Findings suggest a relationship between prolonged ST and reduced OPP, challenging the accepted view that cerebral and ophthalmic circulatory autoregulation prevents elevated compartment pressures and reductions in perfusion.

Causes of blindness and low vision in Bayelsa State, Nigeria: a clinic based study

BACKGROUND

No data are yet available on the causes of blindness and low vision in Bayelsa State of Nigeria.

OBJECTIVE

The study is to provide baseline data on the causes of blindness and low vision in Yenagoa, Bayelsa State, Nigeria.

METHODS

A prospective study was conducted among new consecutive patients presenting at the eye clinic of Niger Delta University Teaching Hospital. Patients with visual acuity of less than 6/18 in the better eye after optical correction or with pin hole as necessary were studied. Their visual acuity was determined using a snellen chart followed by anterior and posterior segment examination using a Haagstreit slit lamp biomicroscope and direct or indirect ophthalmoscope respectively (Keeler). Other information obtained from patients included their age, sex and occupation.

MAIN OUTCOME MEASURE

Visual acuity < 3/60 in the better eye and visual acuity < 6/18 in the better eye.

STATISTICAL ANALYSIS

STATISTICAL ANALYSIS was done using a scientific calculator.

RESULTS

Over a period of one year, 230 patients presented with visual impairement consisting of 124 blind cases and 106 cases of low vision. Their ages ranged from 3 to 90 years with a mean of 48 years. There were 118 males and 112 females giving a male:female ratio of 1:1.1. Cataract and glaucoma were the leading causes of blindness and low vision. Cataract was responsible for 63% of blindness and 49.8% of low vision while glaucoma accounted for 22% of blindness and 17.9% of low vision. The other causes of blindness in decreasing order includes maculopathy (4.3%), retinitis pigmentosa (3.4%), optic atrophy, phtisis bulbi, keratopathy (each 2.6%) and age related macular degeneration (0.9%). The other causes of low vision in decreasing order includes refractive error (15%), maculopathy (5.6), optic atrophy (3.8%), retinitis pigmentosa, retinopathy (each 2.8%) and age related macular degeneration (1.9%). Majority of blindness is avoidable (93.5%), and found in the fifth and sixth decades of life.

CONCLUSION

Cataract and glaucoma are the predominant causes of blindness and low vision in the study population and majority of the blindness (93.5%) is avoidable. A more aggressive approach to clear cataract back log and improvement of early diagnosis and treatment of glaucoma are needed to combart blindness in this community.

Profile of childhood blindness and low vision in Yemen: a hospital-based study

ABSTRACT A retrospective review of records determined the frequency and causes of low vision and blindness in all children aged < 16 years attending an ophthalmic practice in Sana'a, Yemen between January and December 2001. Of the 1104 children studied, 45 (4.1%) were found to have bilateral blindness and 115 (10.4%) were unilaterally blind; 48 children (4.3%) were bilaterally visually impaired and 109 (9.9%) were unilaterally visually impaired. The main causes of bilateral blindness included cataract, glaucoma and retinal disorders. The most common causes of bilateral low vision included refractive errors, keratoconus and retinal disorders. These results provide a basis for planning blindness prevention programmes in Yemen.

[Reducing blindness and visual impairment from glaucoma is an important component in the prevention of blindness]

International ophthalmological societies and World Health Organization (WHO) have recognized the severity of glaucoma problem and the importance for promoting the glaucoma control worldwide. WHO has taken some measures to reinforce the global prevention of blindness from primary glaucomas. The rationale to deal with the glaucoma problem is that glaucomas produce a significant global public health burden at present, and glaucoma can be effectively treated once detected according the evidenced-based practice protocols for glaucoma management. Taking the glaucoma control as the priority for prevention of blindness means not only apply the clinical path, but also apply public health path and integrate various levels of ophthalmic manpower to deal with glaucoma problem. That is a great change in the prevention and management of glaucomas. Screening and early detection of glaucoma cases is very important in glaucoma control. At present, enhancing opportunistic case detection has been used to find more undiagnosed and untreated glaucoma cases, since evidence regarding the benefits of population-based screening is currently lacking. The scope of intervention strategies for glaucoma control should be matched with the local socio-economic status, thus the initiative for glaucoma control can be smoothly developed and progressed.

Reducing vision loss in chronic eye disease

BACKGROUND

Ocular disease in its early stages may be asymptomatic and insidious. Three of the leading causes of visual loss are cataract, age related macular degeneration and glaucoma.

OBJECTIVE

This article discusses the presentation and treatment options for, and the management of, cataract, age related macular degeneration and glaucoma.

DISCUSSION

Few primary prevention strategies are available as these ocular diseases are degenerative. The focus for reduction of visual loss is early detection and regular ophthalmic examination. The aim of management is to improve or maintain vision so as to preserve patient quality of life.

[Elderly people with visual impairment in The Netherlands]

AIM

To estimate the number of elderly people with visual impairment in The Netherlands, now and in the future. Possibilities for intervention are discussed.

METHODS AND MATERIALS

Estimates are based on a recent report on behalf of Foundation InZicht, ZonMw, in which prevalence data from population-based studies on blindness and low vision and its causes in The Netherlands, western Europe, The United States and Australia are related to the latest demographic data for The Netherlands.

RESULTS

Of the 16.4 million Dutch in 2008 2.4 million (14.7%) are 65 years of age and older. Of this last group 155,000 persons are living in nursing homes or residential homes, the others are living in their own homes. In 2008 an estimated 77,000 persons are blind and 234,000 have low vision. Of them 79% is 65 years of age or older. Of the older people in care institutions 20% is blind (32,000) and 22% has low vision (34,000). In 62% of them the visual impairment is treatable or could have been prevented ('avoidable'). Of the older people living independently 1.2% is blind (27,000) and 6.8% has low vision (154,000). In 57% of them the affliction is avoidable.

CONCLUSION

In 2008 247,000 elderly suffer from a visual impairment that could have been treated or prevented in 143,000 (58%) of them. Screening and treatment of elderly in care institutions seems indicated, as is health education to and goal-oriented screening of elderly who live independently.

Far-sighted eye care

Last year the UK launched a vision strategy with the aim of developing an integrated framework for action on sight loss and eye health.

Evaluation of an Eye Health Program: The Vision Initiative

PURPOSE

The aim of this study was to develop an innovative, rapid and economical assessment methodology to determine the knowledge, attitudes and behaviours regarding eye health and to determine the rates of the most common causes of visual impairment and undiagnosed eye disease.

METHODS

Letters were posted to Seniors Card holders aged 70-79 in 18 randomly selected areas, stratified by socio-economic status. A questionnaire was developed to measure knowledge, attitudes and behaviours regarding eye health. Uncorrected refractive error was determined by measuring presenting and best-corrected visual acuity (VA). Diabetic retinopathy and age-related macular degeneration were assessed using digital non-mydriatic retinal photography. Glaucoma was assessed using Frequency Doubling Technology (FDT) and digital images of the optic nerve head. Cataract was determined using digital retro-illumination images of the lens taken with a non-mydriatic camera. The cost for recruiting, examining and grading images for each participant was calculated by dividing the total study cost by the number of participants examined.

RESULTS

Of the 13,483 participants invited to participate in the study, appointments were made for 1860 (13.8%) people with 1,701 (91%) actually attending. Overall, missing data from the 1,695 questionnaires represented less than 1.0% and all participants attended the vision screening over a three-month period. Presenting and best-corrected visual acuity and FDT results on both eyes were obtained on 99% of the sample. The proportion of gradable digital images of the fundus in both eyes in the sample was 89%, while 90% of participants with bilateral presenting VA<6/12 had assessable lens images. The cost for recruiting, examining and grading images for each participant was approximately 150 AUS dollars.

CONCLUSION

The recruitment from a mailing obtained the required sample size for the study, allowing a large sample of participants to be examined efficiently over a short period of time. It is important that the most common causes of visual impairment and undiagnosed eye disease can be determined using this rapid assessment methodology.

[The evaluation of tendency of cataract prevalence from 1987 to 2006 in Zhejiang province]

OBJECTIVE

To evaluate the long-term trend of cataract prevalence and the effect of prevention and treatment blindness in Zhejiang Province.

METHODS

The data were obtained from handicapped sampling investigation in 1987 and 2006 in Zhejiang Province, and from a database of prevention and treatment blindness of the Zhejiang Province Disabled Persons' Federation.

RESULTS

In 2006, a random sampling investigation were carried out on both eyes blind and the low vision in Zhejiang Province. Sample size were 95,392, the prevalence rate of blindness and low vision were 2.67% per hundred and 5.94% per hundred, respectively. The prevalence rate of cataract was 7.35% per hundred, the female was higher than the male (chi2 = 81.66, P < 0.01). Among the blind, 58.86% was caused by cataract, and the low vision caused by cataract was 63.79%. Comparing with the first disabled person' investigation in 1987, the result showed that the prevalence of blindness had reduces slightly, but no significantly difference (chi2 = 0.384, P = 0.535), and that the prevalence of low vision appeared significantly increase (chi2 = 32.434, P < 0.01). Together with two investigations results indicated that cataract is the first cause for the vision disability.

CONCLUSION

Cataract is still the first cause for blindness and low vision. Though the effort to prevention and treatment blindness during 20 years obtains some certain results, prevent and treat blindness will still be an arduous work in Zhejiang province, because of accelerated aging population problem, which will induce an increase on number of cataract patient.

[Agreement measurement of ocular wavefront aberrations with three different aberrometers]

OBJECTIVE

To assess the repeatability and difference of ocular wavefront aberrations measured with ray-tracing, dynamic skiascopy, and Hartmann-Shack aberrometers.

METHODS

It was an agreement study. Ocular aberrations data obtained by using iTrace (Tracey Technologies), OPD SCAN (Nidek) and WASCA (Zeiss) wavefront aberrometers were analyzed. Eighty six eyes of 45 patients were measured three times. The difference between the measurement and the mean of three consecutive measurements were analyzed to verify the reproducibility. The difference in sphere, cylinder, spherical equivalent (SEQ) and high order aberration (HOA) errors obtained from different aberrometers were evaluated.

RESULTS

Repeatability errors of these three wavefront analyzer were found to be low. Comparisons on the same eye showed that there was a significant difference (P < 0.01) in sphere and cylinder between ray-tracing aberrometer and the others in high SEQ group (>or= -6.00 diopter). For HOA, all aberrometers obtained similar results in low SEQ group (< -6.00 diopter). In the high SEQ group, the ray-tracing aberrometer showed statistically higher data in HOA and coma (P < 0.01), and there was no significant difference between the skiascopy and the Hartmann-Shack aberrometer. The iTrace-OPD and iTrace-WASCA HOA difference correlated with spherical equivalent in the high SEQ group (r = -0.418, -0.399, P < 0.01).

CONCLUSION

All devices produced similar results of reproducibility, but showed varying results in the ocular total wavefront reading.

[Blindness in Germany: dimensions and perspectives]

Blindness and visual impairment in Germany and the Western world will increase further over the coming years and decades. This is primarily due to current demographic trends leading to increased visual impairment, mainly in the elderly. In Germany the current situation of the blind and visually impaired is less well documented than in other European countries. The impact of this development can be differentiated into individual and societal dimensions, of which quality of life, morbidity, mortality, and cost are the best-documented aspects. Because of the socioeconomic and cultural importance of vision in Western society, the negative effects of an increase in blindness and visual impairment in a continuously aging population are considerable. Healthcare policy makers need to consider this when discussing future planning and resource allocation. Preventive and rehabilitative services should be given a much higher priority.

PKC inhibition and diabetic microvascular complications

In patients with diabetes, the hyperglycaemia is known to promote high levels of diacylglycerol which activates protein kinase C (PKC) in the vascular tissues and leads to production of vascular endothelial growth factor (VEGF) in the retina. PKC activation is likely to play a key role in diabetic microvascular complications, particularly changes in vascular permeability and ischaemia in the retina. A new potential therapeutic agent, the PKC-beta inhibitor ruboxistaurin, has been studied in animal and human clinical trials in diabetic microvascular disease, particularly in patients with diabetic retinopathy. The mechanism of action of PKC and the results of these trials are discussed in this review. Ruboxistaurin shows promise as an oral treatment for diabetic retinopathy. The trials have demonstrated a significant reduction in visual loss and need for laser treatment in patients with moderate to severe diabetic retinopathy over a 3-year period. There have been no significant concerns over safety or the side-effects profile in the clinical trials. Ruboxistaurin currently has approvable status pending further randomized trials defined by the US Food and Drug Administration (FDA).

Prevalence of refractive error and low vision among schoolchildren in Cairo

A preliminary survey was conducted to detect the prevalence of refractive error (RE) and low vision among 5839 schoolchildren aged 7-14 years in Cairo, Egypt. Screening was done using Landolt broken ring chart and pinhole test. The prevalence of RE (visual acuity < or = 6/12) among the schoolchildren was 22.1% and low vision (visual acuity < or = 6/18) was 12.5%. The prevalence of low vision was greatest among the preparatory schoolchildren aged 12+ years. RE was higher among the female students than males (21.4% and 13.6% respectively). Development of a national survey for detection of visual problems for both preschool and school-aged children is recommended.

[Possibilities for prevention and treatment of blindness and impaired vision in children caused by congenital eye diseases]

Blindness, disability, and impaired vision present important medicosocial problems. According to the WHO, there are 1.5 million blind children in the world. The prevalence of child blindness in Russia is 1.6, and that of impaired vision is 3.5 per 10000 children. It is considered that child blindness can be prevented in 40 to 50% of children. According to data collected during ophthalmological examinations in specialized school, blindness in 88 to 92% of cases is caused by. Presently, significant achievements have been made in treatment of congenital eye diseases. Application of modem surgical techniques in patients with cataract, aphakia, or amblyopia makes it possible to increase visual acuity to 0.3 or higher in 35% of children, and to 0.005 to 0.25 in 45% of children. Modem pathogenetically directed surgery together with timely treatment allows for the normalization of intraocular pressure and visual stabilization in 76.4 to 86.4% of children with congenital glaucoma. In this connection, the achievements of scientific research should be introduced into practice. Realization of the 1999 WHO program on liquidation of eliminable blindness include three key directions: treatment and prevention of blindness; consolidation of the infrastructure and technology of ophthalmological aid; training of specialists.

Prevalence and causes of blindness and low vision in southern Sudan

BACKGROUND

Blindness and low vision are thought to be common in southern Sudan. However, the magnitude and geographical distribution are largely unknown. We aimed to estimate the prevalence of blindness and low vision, identify the main causes of blindness and low vision, and estimate targets for blindness prevention programs in Mankien payam (district), southern Sudan.

METHODS AND FINDINGS

A cross-sectional survey of the population aged 5 y and above was conducted in May 2005 using a two-stage cluster random sampling with probability proportional to size. The Snellen E chart was used to test visual acuity, and participants also underwent basic eye examination. Vision status was defined using World Health Organization categories of visual impairment based on presenting visual acuity (VA). A total of 2,954 persons were enumerated and 2,499 (84.6%) examined. Prevalence of blindness (presenting VA of less than 3/60 in the better eye) was 4.1% (95% confidence interval [CI], 3.4-4.8); prevalence of low vision (presenting VA of at least 3/60 but less than 6/18 [corrected] in the better eye) was 7.7% (95% CI, 6.7-8.7); whereas prevalence of monocular visual impairment (presenting VA of at least 6/18 [corrected] in better eye and VA of less than 6/18 [corrected] in other eye) was 4.4% (95% CI, 3.6-5.3). The main causes of blindness were considered to be cataract (41.2%) and trachoma (35.3%), whereas low vision was mainly caused by trachoma (58.1%) and cataract (29.3%). It is estimated that in Mankien payam 1,154 persons aged 5 y and above (lower and upper bounds = 782-1,799) are blind, and 2,291 persons (lower and upper bounds = 1,820-2,898) have low vision.

CONCLUSIONS

Blindness is a serious public health problem in Mankien, and there is urgent need to implement comprehensive blindness prevention programs. Further surveys are essential to confirm these tragic findings and estimate prevalence of blindness and low vision in the entire region of southern Sudan in order to facilitate planning of VISION 2020 objectives.

Visual field preservation after multisession cyberknife radiosurgery for perioptic lesions

OBJECTIVE

The restricted radiation tolerance of the anterior visual pathways represents a unique challenge for ablating adjacent lesions with single-session radiosurgery. Although preliminary studies have recently demonstrated that multisession radiosurgery for selected perioptic tumors is both safe and effective, the number of patients in these clinical series was modest and the length of follow-up limited. The current retrospective study is intended to help address these shortcomings.

METHODS

Forty-nine consecutive patients with meningioma (n = 27), pituitary adenoma (n = 19), craniopharyngioma (n = 2), or mixed germ cell tumor (n = 1) situated within 2 mm of a "short segment" of the optic apparatus underwent multisession image-guided radiosurgery at Stanford University Medical Center. Thirty-nine of these patients had previous subtotal surgical resection, and six had previously been treated with conventional fractionated radiotherapy (6). CyberKnife radiosurgery was delivered in two to five sessions to an average tumor volume of 7.7 cm3 and a cumulative average marginal dose of 20.3 Gy. Formal visual testing and clinical examinations were performed before treatment and at follow-up intervals beginning at 6 months.

RESULTS

After a mean visual field follow-up of 49 months (range, 6-96 mo), vision was unchanged postradiosurgery in 38 patients, improved in eight (16%), and worse in three (6%). In each instance, visual deterioration was accompanied by tumor progression that ultimately resulted in patient death. However, one of these patients, who had a multiply recurrent adrenocorticotropic hormone-secreting pituitary adenoma, initially experienced early visual loss without significant tumor progression after both a previous course of radiotherapy and three separate sessions of radiosurgery. After a mean magnetic resonance imaging follow-up period of 46 months, tumor volume was stable or smaller in all other cases. Two patients died of unrelated nonbrain causes.

CONCLUSION

Multisession radiosurgery resulted in high rates of tumor control and preservation of visual function in this group of perioptic tumors. Ninety-four percent of patients retained or improved preradiosurgical vision. This intermediate-term experience reinforces the findings from earlier studies that suggested that multisession radiosurgery can be a safe and effective alternative to either surgery or fractionated radiotherapy for selected lesions immediately adjacent to short segments of the optic apparatus.

Surgically Treated Tuberculum Sellae and Diaphragm Sellae Meningiomas

OBJECTIVE:

The visual outcome in patients with tuberculum and diaphragm sellae meningiomas treated with microsurgery was evaluated. Prognostic and diagnostic values of short- and long-term postoperative visual outcome and etiology for postoperative visual deterioration are discussed with special attention.

METHODS:

Clinical data for 30 surgically treated patients with tuberculum and diaphragm sellae meningiomas were reviewed retrospectively. The mean duration of the follow-up period was 75.9 months (range, 12–151 mo). Mean tumor diameter and volume was 25.9 mm (range, 16.3–63.3 mm) and 12.4 cm3 (range, 2.3–125.6 cm3). A visual impairment score was used to assess the short-term (≤2 wk after surgery) and the long-term (&gt;6 mo after surgery) postoperative visual outcome. Various predictive factors for visual outcome were tested statistically.

RESULTS:

Complete resection was achieved in 23 out of 30 (76.7%) patients. Average preoperative, short- and long-term visual impairment scores were 48.2, 43.4, and 40.9, respectively. Favorable visual outcome was achieved in 80% of patients in the short term and 70% in the long term. Short-term postoperative aggravation of visual function was an ominous sign of further aggravation or at least of little hope for recovery, whereas there was a tendency to improve in the long term if short-term postoperative visual function showed favorable outcome. Recurrence or regrowth of tumor fully was responsible for late deterioration of visual function. No significant prognostic factor for visual outcome could be found.

CONCLUSION:

Short-term postoperative visual outcome was a strong indicator of permanent visual outcome after surgery for tuberculum sellae and diaphragm sellae meningiomas.

Screening compliance and visual outcome in diabetes

PURPOSE

To study the relationship between screening compliance and visual outcome in a screening programme for diabetic eye disease.

METHODS

A retrospective case control study. The screening compliance of all the diabetes patients (n = 22) listed at the Icelandic National Registry for the Blind (visual acuity <0.3) was compared to a matched group of 44 non-blind diabetes patients (visual acuity > or =0.3) who participated in the same screening programme for diabetic retinopathy. Glycaemic control (HbA1c), office blood pressure and cholesterol levels were assessed.

RESULTS

The study group had a significantly lower level of compliance with the screening programme (27% +/- 38% [mean +/- SD] versus 77% +/- 26% [mean +/- SD]; p < 0.0001). Macular oedema or proliferative diabetic retinopathy was found in 60% (13/22) of the study group when entering the screening programme, compared to 7% (3/44) in the control group. Blood pressure (except diastolic BP among type 1 diabetes mellitus), blood glucose and cholesterol levels were identical. The prevalence of blindness and low vision amongst diabetes patients in Iceland is about 0.5%.

CONCLUSIONS

There was a significant relationship between screening compliance and visual outcome in diabetes patients in our screening programme.

[A national survey on low vision and blindness of 0 - 6 years old children in China]

OBJECTIVE

To get the prevalence of visual impairment of children in China. The national survey of low vision and blindness of 0 approximately 6 years old children was conducted in China in 2001.

METHOD

Stratified, random, cluster, systematic sampling was used to select 60 124 subjects from 360 clusters from 6 provinces in China. The trained doctors examined every individual.

RESULT

64 subjects were defined as visual impairment among the total 60 124 participated subjects in the survey. The total prevalence of visual impairment is 1.1 per thousand. The 20 subjects is blindness and the prevalence is 0.33 per thousand. 44 subjects is low vision and the prevalence is 0.73 per thousand. The major causes of visual impairment are amblyopia (32.8%), retinal and optic nerve diseases (15.6%), congenital cataract (14.1%) and congenital glaucoma (6.3%).

CONCLUSION

The prevalence of blindness is close the level of developed country. Amblyopia is the leading cause of all visual impairment. Most causes of visual impairment, amblyopia and congenital cataract are curable.

[Complications during the neonatal period can cause visual impairment later in life. Only few of the children were born prematurely--a surprising result of the study]

Forty per cent of children known at our low vision centre at the Department of Ophthalmology, University Hospital, Linköping, Sweden, had been treated in a neonatal ward after birth. Only few of them were born prematurely. Half of the children had an additional neurological handicap. The present neonatal screening program detects most cases of congenital cataract and all cases with retinopathy of prematurity.

Resource allocation to prevent trachomatous low vision among older individuals in rural areas of less developed countries

Trachomatous low vision can be prevented by treating or preventing infection or through surgery to treat trichiasis. Resource allocation to prevent trachomatous low vision should be directed to those interventions that are the most cost-effective. In order to assess which of many potential interventions are the more cost-effective, data on the epidemiology of the disease, the effectiveness of community- and facility-based interventions, and the cost of the interventions are required. This paper provides a stylized model of the path from risk of infection through disease to trachomatous low vision or blindness that delineates the points at which interventions may occur and for which data are required. The literature reveals a considerable amount of data regarding the epidemiology of the trachoma and its sequelae but little on the effectiveness of community-based interventions and only one study that measured costs directly. More data are needed to assist policy makers and international program partners who seek to make efficient resource allocation decisions in an effort to eliminate trachoma as a cause of incident blindness in the developing countries in which trachomatous blindness remains prevalent.

[Complex visual hallucinations in partially sighted elderly: Charles Bonnet syndrome]

In two patients, women aged 85 and 80 years, who suffered from visual hallucinations involving living creatures, cars and buildings, Charles Bonnet syndrome was diagnosed. Both were worried that these signs were an indication of a severe psychiatric condition. In diagnosing the Charles Bonnet syndrome the following criteria can be used: presence of complex visual hallucinations, retention of insight, absence of hallucinations in other sensory modalities and absence of delusions. Hallucinations in dementia, delirium, migraine, epilepsy, or in extreme states of exhaustion or sensory deprivation, as well as hallucinations due to psychedelic drugs, hallucinations of widowhood and hypnagogic and hypnopompic hallucinations must be excluded. Patient education and reassurance are the cornerstones of treatment. Other possible treatments are: improving visual acuity and the general physical condition, stopping medication with hallucinogenic side effects, activating the patient, coaching the patient in avoiding hallucination-triggering situations and using stopping strategies, and (still experimental) pharmacological treatment with carbamazepine, valproate, ondansetron or cisapride.