Glaucoma is estimated to affect 12 million Indians; it causes 12.8% of the total blindness in the country and is considered to be the third most common cause of blindness in India.1234 The prevalence of glaucoma in India ranges from 2.6% (95% CI: 2.2 - 3.0)5 to 4.1% (95% CI: 0.08 - 8.12).6 According to the Andhra Pradesh Eye Disease Study (APEDS), the prevalence of primary open angle glaucoma (POAG) in urban India among people 30 years of age or older was 1.62% and 0.79% of that age group had suspected POAG.7 What was surprising was that 92.6% of those with definite POAG had not been diagnosed or treated earlier. Of these previously undiagnosed participants, 48% had severe glaucomatous damage, including 16% who were blind in one or both eyes as a result of POAG. Among those with newly diagnosed definite POAG with an IOP of 22 mmHg or more in one eye, 63% had severe glaucomatous damage and 38% were blind in one eye. On the other hand, primary angle closure glaucoma (PACG) accounted for 41.7% of blindness due to glaucoma in one or both eyes in this urban population of India and only one-third of those with manifest PACG had been diagnosed earlier.8 Half of those previously diagnosed were blind in one or both eyes as a result of PACG ;this has been attributed to late diagnosis or inadequate treatment.8 Most of the population based prevalence studies from India have reported low rates of preexisting disease diagnosis among their subjects.9
Glaucoma is considered the"sneak thief of sight" and it is agreed that early detection and treatment can prevent progression of the disease. Implementation of health education programmes that encourage people in the community to obtain eye examination may identify those who are otherwise unaware or unwilling to seek examination and treatment. The aim of this article was to evaluate the level of awareness regarding glaucoma in the rural population of Andhra Pradesh (AP). The information can help develop appropriate strategies to address the issue in this rural population.
Materials and Methods
The methodology of the APEDS has been described in detail10-11 The Ethics Committee of the Institute approved the study design which followed the tenets of the Declaration of Helsinki. The study was conducted over a period of five years from 1996 to 2000.
A systematic, cluster, stratified random sampling procedure was used to select 70 clusters from three rural areas from the Indian state of AP, to obtain a study sample representative of the socioeconomic distribution of the population of the state. These areas were located in the following districts:
- West Godavari (a prosperous rural area)
- Adilabad (a poor rural area)
- Mahabubnagar (a poor rural area)
For the rural segments of APEDS, 8,832 subjects were sampled; 7775 (88%) eligible volunteers participated in the study. The principal investigator and one of the coinvestigators of the APEDS study imparted special training in the interview procedures of APEDS to an anthropologist, a sociologist and two experienced field investigators. Interview procedures were refined during the course of the pilot study. Validity of the various methods including the questionnaire used in APEDS was tested over a series of focus group discussions and trial runs. The focus group consisted of eye care professionals, public health experts and field investigators. After the group discussions were tested on a group of patients in a pre-pilot study, appropriate methods were adopted and the input of patients was noted for improving the methods.10 The questionnaire was initially developed in English and all the questions were translated into the two most common local languages, Telugu and Hindi for the target population. Terms used in the local languages for the eye diseases assessed were identified from the eye-care personnel, patient counsellors and patients at the L.V. Prasad Eye Institute, Hyderabad, India. Pilot studies were performed in both urban and rural areas to check the validity and reliability of the methods developed for APEDS. Modifications were made wherever necessary. Reliability was tested amongst the field investigators for the administration of the questionnaire.10
Subjects were asked if they had heard of eye diseases.. Further questions were asked about that particular eye disease only if the subject responded positively. Those who had heard of eye diseases were asked to explain what that eye disease was. The questionnaire contained a list of possible responses. The field investigator marked the response provided by the subject against the response it most closely approached on the questionnaire. If the response did not correlate with any of the responses listed on the questionnaire, it was documented in greater detail. Awareness was defined as "having heard of glaucoma". Knowledge was defined as "when the subject had some understanding of glaucoma"for instance, "it is a high pressure in the eye", "it is a disease where nerve of the eye becomes weak", "it is a damage to the nerve of the eye due to high-pressure" and so on.
Statistical analysis was performed with the SPSS (SPSS for Windows, Rel 11.0; 2002. SPSS Inc, Chicago, IL, USA) software. The relationship between awareness of glaucoma and demographic factors such as age, gender, socioeconomic status, education and social status was assessed using the univariate Chi-square test or Fisher's exact test. A two-tailed 'P' value of less than 0.05 was considered statistically significant. The prevalence rates were adjusted for the estimated age and gender distribution of the population in India for the year 2000 (http://www.census.gov). The design effect (DE) of the sampling strategy was calculated using the prevalence estimates in each cluster; 95% confidence intervals (CI) of the estimates were calculated by assuming normal approximation of binomial distribution for prevalence of 1% or more and Poisson distribution for prevalence less than 1%.12
A total of 7775 volunteers participated in three rural areas of AP, (participation rate -88%). Subjects older than 15 years of age (n = 5573) responded to a structured questionnaire on awareness of eye diseases, one of which was glaucoma. Data were analysed for these 5573 (71.7%) subjects. Of these, 3011 (54%) were females; 88 (1.6%) belonged to the upper socioeconomic group (Table 1). A total of 18 (0.33%) subjects were aware of glaucoma in this studied population. Age-gender-adjusted prevalence of awareness of glaucoma was 0.27 (95% CI: 0.13 - 0.40; DE = 4.20). Males were more aware of glaucoma compared to the females (0.50% vs 0.10; p = 0.007). Literate persons and forward social class people (both the groups were defined as per criteria used for APEDS10 were also significantly more aware of glaucoma (p < 0.0001).
Responses to the questions on glaucoma are presented in Table 2. Of the 18 subjects who were aware of glaucoma, only one subject (5.6%) felt that glaucoma was high pressure in the eye; none responded that it was damage to the nerve of the eye due to high pressure. A total of 11 (61.1%) responded that they did not know what glaucoma was ;and the rest of them said that it was damage to the retina, haloes around the eyes and pain in the eyes. The source of information for awareness of glaucoma was
- mass media in 8 (44.4%) subjects;
- a family member, relative or friend suffering from the disease in 3 (16.7%) subjects;
- an ophthalmologist in 2 (11.1%) subjects.
A total of 10 (55.6%) subjects said that they did not know whether visual loss due to glaucoma was permanent or reversible. Table 3 compares the current and past study on awareness of glaucoma.
Glaucoma is one of the leading causes of irreversible blindness in developing nations. It is now increasingly being recognised as a major cause of ocular morbidity that requires urgent attention.13 To the best of our knowledge, this is the first population-based data available on awareness of glaucoma from the rural community in India (Medline search). There is one report on such awareness from a rural area in China.14 Awareness of glaucoma in our rural study population was very poor compared to the urban population.15 This situation is significantly worse in India compared to the published data from other countries (Table 3). On the other hand, recently published data suggest that the prevalence of glaucoma in rural India at 2.6%, is probably higher compared to that in the urban community.5 Even among the rural people who were aware of the disease, knowledge about glaucoma was very poor.Limited access to medical and diagnostic care in the rural areas may have contributed to poor knowledge and awareness of glaucoma. Adequate access and proper utilisation of eye care services can create greater awareness and exposure to information about various eye diseases including glaucoma.16 Though awareness of glaucoma in the urban population was not very high, those who were aware had reasonable knowledge of the disease.15
Education and socioeconomic status played a significant role in the level of awareness of glaucoma in this rural population. Those who were illiterate in rural India were less aware about glaucoma, and this trend was similar to those reported from the United States and Australia.161718
None of the participants in our study knew that"glaucoma was damage to the nerve of the eye due to high pressure". Our data also showed that few of the (n = 4; 23%) postgraduates and professionals were well informed about the disease (data not shown).
While many complicated eye diseases can be treated in hospitals, public awareness of vision care issues remains low. Effective eye health education may influence individuals to consider screening and eye care. This may lead to early detection of glaucoma and prevent blindness.19 Educating the rural community on the consequences of delayed treatment of glaucoma will be an important first component in the promotion of preventive ophthalmic care. Mass media and word of mouth can be effective tools for generating awareness on regular and timely eye check up particularly for those who are above 40 years of age and blood relatives of glaucoma patients. The strategy should be to increase awareness of glaucoma in selected high-risk target audience in the rural community.22
The authors thank all the APEDS team, and in particular, Lalit and Rakhi Dandona, who designed and conducted the detailed study; Pyda Giridhar and MNKE Prasad for interviewing the volunteers; and all the volunteers for participating in the study.
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Appendix: The questionnaire
Appendix: The questionnaire
- Have you heard about glaucoma? (0 No, 1 Yes)
- What is glaucoma? (if ‘yes' for above)
- It is high pressure in the eye (0 No, 1 Yes)
- It is a disease where nerve of the eye becomes weak (0 No, 1 Yes)
- It is a damage to the nerve of the eye due to high pressure (0 No, 1 Yes)
- It is an age related process leading to decrease in peripheral vision (0 No, 1 Yes)
- Others (Specify)
- How did you come to know about glaucoma?
- Eye camp
- Family member/relative/friend suffering from it
- TV, Magazines or other media
- Is visual loss due to glaucoma permanent or reversible?
- Don't know