Cataract is an increasingly common cause of global blindness, particularly in developing countries with an aging population and insufficient health care resources. The profile of cataract patients in Rangoon has been described, and senile form was the commonest. However, it has not been documented in the rural areas with no modern facility available.24
Seventy percent of Myanmar’s population live in rural areas and at least 25% of the population live below the UN poverty line.25
The National health Plan recognizes the right to sight in the VISION 2020 program, one of the goals of which is to reduce the blindness rate in Myanmar to less than 0.5%. Cataract removal and increasing the quality of services of cataract removal, along with development of the human and technical resources are key strategies in achieving that goal.26
Age-related cataract is the leading cause of blindness in Asia and has been documented in rural Myanmar.2
Similar to our findings, cataract was the leading cause of both blindness and low vision, accounting for approximately two thirds of the visual impairment in the MES. The prevalence of any cataract including operated eyes was 40.39%, and cataracts were strongly associated with increasing age, and are more common in those with lower education and lower body mass index.8
In our series, cataract was also the main reason for blindness. Most of the patients had mature or hypermature cataract, and considering the simple operating facility (a microscope with a simple lens system, lack of phaco-emulcification) shallow anterior chambers and deep located eyes all make this operation more difficult. The prevalence of PXF in the Burmese population is greater than previously reported in other East Asian populations. Increasing age and IOP are the strongest predictors of PXF, and it is associated with cataract, occludable angles and blindness.7
Glaucoma is recognized as the second most common cause of blindness worldwide, disproportionately affecting women and Asians, and is expected to afflict 8.4 million people by 2010.27
The principal reasons for the increase in global glaucoma blindness relate to the aging population in both developed and developing countries and the inadequate detection and treatment of the disease. It is well recognized that primary angle-closure glaucoma (PACG) is generally more common in people of Asian extraction compared with other ethnicities.29
In the MES, glaucoma caused 17% of the nonrefractive blindness. It is in accordance with our 15.8% of visual impairment associated with glaucoma. The prevalence of glaucoma in the MES of any category in at least one eye was 4.9%. The overall prevalence of PACG was 2.5% and of primary open-angle glaucoma (POAG) was 2.0%. PACG accounted for 84% of all blindness due to glaucoma, with the majority due to acute angle-closure glaucoma.
PACG was associated with increasing age, axial myopia, and IOP. It had a more devastating affect on vision than primary open-angle glaucoma and was accounted for 84% of all blindness due to glaucoma, with the majority due to acute angle-closure glaucoma.2
POAG in this Burmese population was associated with increasing age, axial myopia, and IOP.14
The prevalence of preglaucomatous angle-closure disease (primary angle-closure suspects and peripheral anterior synechiae) in this population was 5.7% and 1.5%, respectively.15
The central corneal thickness in this Burmese population was significantly associated with IOP and spherical equivalent.9
Trachoma has been a major cause of blindness for many centuries. It has led to conjunctivitis, cicatricial lid changes, and corneal opacity among populations who have been socioeconomically disadvantaged and those who have been exposed to hot, dry, and dusty environments without adequate access to water and facial hygiene. The socioeconomic and climatic conditions of central Burma, also known as a “dry zone,” make it a suitable environment for high rates of active trachomatous inflammation and subsequent blindness.17
Although its prevalence in certain areas is declining, trachoma continues to account for at least 3.6% of world blindness.27
At present trachoma is still the world’s leading infectious cause of blindness.32
It is estimated by WHO that at present there are 146 million people worldwide with trachoma. Ten million suffer from trichiasis and need surgery to prevent corneal blindness from developing, and another 4.9 million are totally blind from trachomatous corneal scarring.33
Trachoma in Myanmar has been known to be a problem for years. However, Myanmar has had a Trachoma Control Program (TCP) in operation since 1964.35
Surgery, antibiotics, facial cleanliness, and environmental change strategy by the involvement of the WHO not only has proven effective in reducing the prevalence of active infection and potentially blinding trachoma-related trichiasis and corneal opacity (CO), but also has been accompanied by a decline in the incidence of trachoma-related blindness and visual impairment.35
In the Kyaw’s report from 1978, the prevalence of active disease in rural Myanmar ranged from 29.4% to 38.4%.36
The recent reported prevalence population prevalence of trachomatous trichiasis and CO in the MES was relatively low (2.6%).17
Our result show a relatively low incidence of visual impairment associated with trachoma: twenty five eyes (4.7%). We could recognize only 20 suspected cases of new trachoma and prescribed tetracycline ointment for those patients.
The significant improvement is attributed 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. However, the trachoma program in Myanmar does not cover the entire country as much of the government health service does not reach into the ethnic-held areas of Myanmar.
Corneal disease, notably trauma and infection in developing countries has only recently been recognized as a “silent epidemic”.37
In 1992, Thylefors drew attention to the fact that trauma is often the most important cause of unilateral loss of vision in developing countries and that up to 5% of all bilateral blindness is a direct result of trauma.38
Findings suggest that corneal ulceration may be much more common in developing countries than previously recognized, usually associated with agricultural work and that epidemics may currently be occurring on a global scale.39
Most of the population in Myanmar are farmers working the field with primitive instrumentation and no awareness of protection. Twenty-seven of the screened patients (5.1%), had trauma responsible for varying degrees of visual loss. These problems call for respectively prevention and early treatment. Auxiliaries moving through communities can be an effective first line of defense.
Measles can also precipitate severe vitamin A deficiency, resulting in increased systemic morbidity, mortality, corneal ulceration, and blindness.
Vitamin A deficiency remains an important cause of ocular morbidity among patients with chronic liver disease and lipid malabsorption, and is a major cause of blindness in developing countries children who receive vitamin A supplements to protect their eyes are also less susceptible to diarrhea and measles.40
In the MES, age-related macular degeneration was responsible for one case of bilateral blindness. It is relatively uncommon in this population, a finding consistent with other studies in developing regions, similar to our study findings.2
The prevalence of pterygium in central Myanmar in the MES was high: in either eye, it was 19.6% and of bilateral pterygium 8.0%. The risk of developing this condition increases with outdoor occupation. Pterygium in this population is associated with 0.4% of binocular visual impairment and 1.0% of visual impairment in a least one eye.13
We did not consider refractive error as a cause for VI, unless it was not correctable.
In the MES, uncorrected refractive error caused 28.6% of the presenting blindness. Spectacles are not available in the Mount Popa region and they carry socially undesirable connotations. Community programs are needed that can detect uncorrected refractive error, can educate villagers about availability and affordability, and can alter self-image agendas regarding the wearing of spectacles.2
The prevalence rates of myopia in MES were higher than those found in other Asian regions and are likely to contribute to visual impairment. The mean refractive error in the MES was 1.3 diopters (D), and the prevalence of myopia of 0.5 D and myopia of 1.0 D were 51.0% and 42.7%, respectively. Myopia of 6.0 D occurred in 6.5% of subjects, hypermetropia of 1.0 D occurred in 15%, and astigmatism worse than 1.0 D occurred in 30.6%. Anisometropia of 1.0 D or more was 35.3% of subjects and severe anisometropia of 2.0 D or more was present in 18.9%. The higher rates of myopia and anisometropia in this population was attributed to a higher incidence of cataract.2
Myopia and cataract, but not increasing age, are the potential risk factors of anisometropia in this population.10
The current study has several limitations. The study is a summary review of our clinical records, but it is not a population-based epidemiology study. The population of Myanmar is multiethnic. Since the patients came from throughout the district or provinces they could belong to different ethnics with more than one hundred minority groups in the area. As a result of the lack of common language we couldn’t get a profile regarding ethnicity. It is reasonable that different ethnic groups present different ocular pathologies.
Because of logistical constraints, and the lack of more ophthalmologists, we could not make refraction available to the patients. Corrected vision was taken as pinhole vision using a multifenestrated occluder. It is likely that a subjective refraction would have improved a percentage of subjects further. As a result, a percentage of participants are likely to have been wrongly categorized with nonrefractive causes of VI. Thus, the current study overestimates the WHO grades of VI.
Using the monastery system, the surgical needs of cataract or trachoma and the laser requirements in glaucoma can be met by regional centers which are suitably equipped, provided that these services are affordable for the poor. Some strategies for the control of blindness in patients are already being implemented. Since so many cases are treatable, and some are also preventable, vision screening in schools and villages in rural regions in Myanmar are required. The challenge is to ensure that the control of blindness will be available also to the majority of the population with no access to any medical service. It seems that a lot more work should be invested in Myanmar in order to help many VI cases.
To conclude, VI is still significant in Mount Popa region. Lack of resources, cost, remoteness, lack of awareness of available treatment, fatalism, and fear of surgery are some possible explanations. Measures to reduce blindness include more skilled ophthalmologists and optometrists in this region, population education, and subsidies for those who cannot afford ophthalmic service and surgery.