Early detection of visual impairment and its relation with school effectiveness

Abstracts

OBJECTIVE: To detect early visual acuity deficiency of school children and its association with school performance METHODS: A cross-sectional study was conducted with a sample from the third year of elementary schools in the city of Juiz de Fora, Minas Gerais. The examination of visual acuity (VA) was carried out using Snellen Scale, an analysis of transcripts was made and a self-administered questionnaire, previously validated was used. Visual acuity loss was considered when the index obtained by the scale was less than or equal to 0.7 and poor academic performance when the average scores of the last school year did not reach 60 points. RESULTS: We analyzed 222 students from five public schools. Regarding visual acuity, 31% of students had a change in the right eye and 29.8% had a change in the left eye. In this sample, 15.5% of the students had unsatisfactory or poor school performance. Among the students with normal VA , 89.5% had satisfactory school performance, while among those with VA changes, only 75% had such a performance (p-value: 0.015). CONCLUSION: This study suggests an association between low visual acuity and poor school performance in the sample analyzed.

Visual acuity; Ophthalmology; Underachievement; Eye health; Visual perception

OBJETIVO: Detectar precocemente deficiência na acuidade visual de escolares e verificar sua associação com o rendimento escolar. MÉTODOS: Estudo transversal realizado em amostra de escolares do terceiro ano do Ensino Fundamental da rede pública do município de Juiz de Fora, Minas Gerais. Foram realizados o exame de acuidade visual (AV) com o uso da Escala de Snellen e a análise do histórico escolar, bem como foi utilizado questionário autoaplicável, previamente validado. A baixa acuidade visual foi considerada quando o índice obtido pela escala foi menor ou igual a 0,7 e o baixo rendimento escolar quando as médias das notas do último ano letivo não alcançaram 60 pontos. RESULTADOS: Foram analisados 222 estudantes provenientes de cinco escolas públicas. Em relação à acuidade visual, 31% alunos apresentaram AV alterada no olho direito e 29,8% alunos apresentaram AV alterada no olho esquerdo. Na amostra estudada, 15,5% dos alunos apresentaram rendimento escolar regular ou insatisfatório. Entre os alunos com AV dentro da normalidade, 89,5% apresentaram rendimento escolar considerado satisfatório, enquanto que, entre aqueles com AV alterada, apenas 75% apresentaram tal rendimento (p=0,015). CONCLUSÃO: O presente estudo sugere a existência de associação entre baixa acuidade visual e baixo rendimento escolar na amostra avaliada.

Acuidade visual; Oftalmologia; Baixo rendimento escolar; Saúde ocular; Percepção visual

ORIGINAL ARTICLE

Early detection of visual impairment and its relation to academic performance

Carolina Cumani Toledo^I,*; Ana Paula Garcia Paiva^I; Gustavo Bittencourt Camilo^I; Márcio Ribeiro Sotto Maior^II; Isabel Cristina Gonçalves Leite^III; Maximiliano Ribeiro Guerr^IV

^IAcadêmicos de Medicina pela Faculdade de Medicina da Universidade Federal de Juiz de Fora (FACMED/UFJF), Juiz de Fora, MG

^IIDoutorado em Oftalmologia pela Universidade Federal de Minas Gerais - Adjunto IV da Universidade Federal de Juiz de Fora - UFJF, Juiz de Fora, MG

^IIIDoutorado em Saúde Pública pela Escola Nacional de Saúde Pública - Odontopediatra nível III da Prefeitura Municipal de Juiz de Fora e professora adjunta da Universidade Federal de Juiz de Fora - UFJF, Juiz de Fora, MG

^IVDoutorado em Saúde Coletiva pela Universidade do Estado do Rio de Janeiro e professor titular da Universidade Federal de Juiz de Fora - UFJF, Juiz de Fora, MG

ABSTRACT

OBJECTIVE: To perform early detection of visual impairment in schoolchildren and to investigate its association with academic performance.

METHODS: Cross-sectional study using a sample of third-grade students from public elementary schools of the municipality of Juiz de Fora, state of Minas Gerais, Brazil. Students performed the visual acuity (VA) test using the Snellen chart. We also analyzed school records and administered a previously validated self-administered questionnaire. We considered that there was low VA when the VA value achieved using the chart was lower than or equal to 0.7, while poor academic performance was identified when the average grades of the last school year did not reach 60 points.

RESULTS: We analyzed 222 students from five public schools. In terms of visual acuity, 31% of the students had impaired VA in the right eye and 29.8% of the students had impaired VA in the left eye. Our sample had 15.5% of students with fair or poor academic performance. Among the students with normal VA, 89.5% had satisfactory academic performance, while among those with impaired VA, only 75% achieved satisfactory performance (p = 0.015).

CONCLUSION: The present study suggests that there is an association between low VA and poor academic performance in the sample assessed.

Key words: Visual acuity. Ophthalmology. Poor academic performance. Eye health. Visual perception.

INTRODUCTION

Early detection of vision problems is an important primary care measure because around 85% of our relationship with the outside world is accomplished primarily through vision; therefore, eye problems may impair children's learning and socialization¹.

According to the most recent census carried out by the Brazilian Institute of Geography and Statistics (IBGE) in 2000, approximately 16.5 million people had visual disability in Brazil (almost 10% of the population). Of these people, 20 to 30% were children with visual acuity (VA) problems².

A research conducted by the Brazilian Council of Ophthalmology (CBO) showed that there were between 1 and 1.2 million blind people and 4 million people with severe visual disability in Brazil in 2004, and 5% of the children had at least one blind eye and 60% of blindness cases could be prevented with early treatment. Also, according to the World Health Organization (WHO), about 500,000 children become blind in the world every year³.

Visual disability at an early age impairs the development of motor skills, cognition, and language during significant periods of child development. Low VA may affect several areas of child development related to skills mediated by vision⁴.

Thus, Temporini (2007) states that schools are institutions where a large number of children get together and the performance of VA tests at this stage of life enables a partial bridging of the gap between birth and school entry⁵.

Ophthalmologic disorders are a major cause of limitations at school age with regard to the teaching-learning process. The most common causes of reduced VA in students are refractive errors (hyperopia, astigmatism, and myopia), strabismus, and amblyopia, while uncorrected refractive errors are a major cause of visual disability in Brazilian children. Early detection of refractive errors allows for their correction or minimization with the purpose of promoting better overall performance of school-age children⁶.

It has also been demonstrated that the implementation of programs for the detection of low VA and prevention of ophthalmic problems in developed countries have significantly lower costs than the costs of the treatment of patients with eye disorders⁷.

EHowever, in developing countries, socioeconomic and cultural factors prevent or hinder children from having access to ophthalmologic examination before school entry. Unfortunately, the public health system in these countries does not provide children with easy access to such examination. Thus, the implementation of screening programs of VA in students is a great opportunity to evaluate their eye health and, sometimes, it is the first and rare chance of vision assessment for most students⁸.

Hence, children's eye health should always be assessed regardless of age group and presence of symptoms. Therefore, early detection of visual disabilities and treatment, thus avoiding learning disorders, are strategies able to decrease the rates of grade retention and, as a consequence, the dropout rates, since low VA has a major influence on school dropout^8,9.

The objective of the present study was to achieve early detection of impaired VA in students and to identify its association with their academic performance, enabling actions that prevent and treat ophthalmologic disorders and promote eye health in schools.

METHODS

Cross-sectional study aimed at detecting visual disabilities in children of both sexes enrolled in the third grade of elementary school of public state and city schools located in Juiz de Fora, state of Minas Gerais (MG), Brazil. Schools were randomly selected. The sample size was set based on the formula used in study cited by James et al. (2005), which considered that 20% of the children aged between eight and ten years had low VA, with a suspected prevalence variability of 15% to 25%¹⁰.

The third grade was selected because the study sample was restricted to children between eight and 10 years old. The choice of this age group was based on the fact that the optical system continues to develop after birth, reaching its maturity at around seven years of age. Therefore, vision, which results from a learning process, reaches its maximum potential at this age. Thus, we selected the age at which children already achieved full visual maturity, allowing for early diagnosis of low VA (VA lower than or equal to 0.7)¹¹. Moreover, it is expected that during third grade students have already mastered reading, which makes it easier to perform the examination using the Snellen chart.

Snellen's test provides an initial diagnosis of the students' eye health status. Its administration is recommended as a prerequisite for referral to an ophthalmologic examination, as an ophthalmologist is responsible for establishing the final diagnosis of the case and the proper treatment¹². Researchers were guided using an informative script about how to carry out the examination. They were also trained by an expert in the field and examined a pilot sample.

The children received a previously validated questionnaire to be answered by their parents, that is, the questionnaire was based on the study by Granzotto (2003) and was administered to a pilot sample⁷. Among other data, this questionnaire included the results of the students' VA tests, personal data, academic performance, and the children's perceptions of their own vision. Next, VA was measured using the Snellen chart.

As for the guidance offered to the children, the researchers provided the students with information about the test in the classroom. In addition, lectures on the importance of early diagnosis of visual disorders were held for students, parents or guardians, and teachers.

Those students who did not attend school on the days scheduled for examination, as well as those who did not provide the questionnaire with parental permission and the informed consent form, were excluded from the study. We also excluded the students wearing corrective lenses or glasses, with total visual disability (blind) and those who did not belong to the predetermined age group (between eight and 10 years old).

Data regarding VA were collected at the schools, in rooms adequately prepared for this activity. In order to analyze these results, we considered that normal VA was higher than 0.7 (according to the Snellen chart), while the values of VA impairment were equal to or lower than 0.7, according to the criteria proposed by the WHO. Students with VA equal to or lower than 0.7 in at least one eye, with or without signs and symptoms, were considered to have low VA¹³.

The outcome variable was the researchers' evaluation of the student's performance considering the average grades of the last school year included in their school records¹⁴. According to the criterion suggested by Hanff¹⁵, an annual attendance rate of at least 75% and a general average grade of 60 points or higher are required for approval in the numerical quantitative system. In the present study, academic performance was considered as follows: satisfactory - overall average grade higher than or equal to 70 points; fair - overall average grade lower than 70 points up to 60 points; and poor - overall average grade lower than 60 points.

It is important to emphasize that we did not measured the variables that could also be related to the outcome, such as cognitive deficits, severe emotional disorders, family background, influence of school environment, and educational discontinuities caused by changes of schools. Depending on each context, such factors can be decisive for the occurrence or maintenance of learning problems¹⁴.

The present study was approved by the Research Ethics Committee of Universidade Federal de Juiz de Fora (UFJF), report no. 089/2008, with prior authorization provided by the educational institutions and the children's parents or guardians, seeking cooperation and authorization to complete this work.

The participants who had low visual acuity in at least one eye, regardless of symptoms and academic performance, were referred to the Outpatient Clinic of Ophthalmology, University Hospital, Health Care Center, Universidade Federal de Juiz de Fora (HU/CAS-UFJF). Priority appointments were scheduled in the Primary Health Care Unit of the district where the student lived upon presentation of a medical authorization document signed by the service physicians. When this was the case, the students' parents or guardians received the result of the test and were informed about the need of seeing a specialist.

RESULTS

We assessed students from five public schools, two state and three city schools, randomly selected considering the proportionality of the public schools in the municipality.

All third-grade students of elementary school from the schools selected were invited to participate in our study. First, we identified 104 students from state schools and 118 from city schools. Of this total, 42 wore glasses and 19 did not return the informed consent form properly filled out, being excluded from the study. Thus, we assessed 161 students.

With regard to sex, 50.9% of the sample was female. In relation to any previous ophthalmologic examinations, 67.7% reported that they had never undergone such a test. Of the participants, 38.5% reported blindness or visual disability in 1st degree relatives and 20.5% could not provide such information. Regarding the presence of glaucoma or treatment for this disease in 1st degree relatives, 46.6% of the students reported that there were no cases of glaucoma in their families, 23.6% said that there were cases of glaucoma, and 29.8% did not know. Table 1 shows the main characteristics of the study population.

In relation to the children's perception of their own vision, 48.40% reported they could see well and the others reported some perceived abnormality (1.30% had double vision; 14.60% had blurred vision, 7% had nearsightedness; 1.90% had farsightedness). In terms of visual acuity, 50 students had impaired VA in the right eye and 48 students had impaired VA in the left eye. The frequency of grade retention was 16.1%.

The analysis of the distribution of visual acuity in students according to their visual self-perception showed the report of abnormal/impaired vision in 37.5% of students with low visual acuity (vs. 23.8% of the students with normal VA) and, among those with normal visual acuity, 55.4% of students reported no vision impairment (vs. 35.7% of the students with impaired VA) (p = 0.05) (Table 2). We found that among students with normal VA, 89.5% showed satisfactory academic performance, while among those with impaired VA, only 75% achieved satisfactory academic performance, that is, 25% had fair or poor academic performance (p = 0.015) (Table 3).

The selection of the study population was based on random sampling, and after all exclusions related to the predefined criteria, only 8.6% of the cases previously identified (n = 19) did not provide the authorization for assessment, suggesting little influence of the healthy patient bias in the present study.

DISCUSSION

Assessment and detection of potential eye problems should occur as early as possible because the longer the delay in identifying visual problems, the smaller the chances of recovery and correction of the problem, in addition to the fact that eye problems promote deficit of academic performance and socialization and are related to child emotional and psychological disorders^13,16 .

In the present study, we found low visual acuity in 34.8% of the students. Such finding is in disagreement with the results of studies using similar methodology but performed in public schools that had programs of ophthalmologic examination and campaigns for early detection of visual disorders. In the study conducted by Granzoto et al., 15.1% of the students had low visual acuity⁷, and, in studies conducted by Ventura et al. and Figueiredo et al., these percentages were 17.3% and 11, 9%, respectively^5,17.

Approximately two thirds of our sample neither had seen an ophthalmologist nor had undergone visual acuity screening, either at school or at their pediatrician's office. Such finding was also found in the study conducted by Soldera, which assessed students from Rio Grande do Sul between four and 15 years old using the Snellen chart¹⁸. This finding suggests a reason for concern: children are not being adequately assessed in terms of visual acuity in Brazil.

Regarding visual self-perception, the highest percentage of abnormal/impaired vision reports was found among those students with low visual acuity (37.5%) and the highest percentage of normal vision reports was observed among those with normal visual acuity (55.4%) (p = 0.05). However, we found a high frequency of students who did not report abnormalities in their visual perception among those who had low visual acuity and high frequency of students with impaired visual perception among those who had normal visual acuity (35.7% and 23.8%, respectively). These findings may reveal students' difficulty to express their visual perception, depending on their age and they may also be influenced by the high percentage of students who were unable to provide such information (36 students - 22.9%).

The Snellen chart was used mainly because of its easy administration. According to Temporini (1993) "in a WHO report, visual acuity is considered the best indicator of visual functioning, and the administration of this test does not require extensive training for examiners or use of sophisticated equipment"⁵.

The definition of academic performance was based on the technically recognized literature¹⁵. However, it is important to consider the progressive inclusion of new assessment methods in the Brazilian educational system in recent decades, such as automatic approval¹⁹, which may have hampered the characterization of poor academic performance, with a probable stronger influence on public schools.

Among students with low visual acuity, 25% of them had fair or poor academic performance, which was a significant percentage when compared with students with fair or poor academic performance but normal visual acuity (10.5%) (p = 0.015). Therefore, it is important to provide professionals with qualified training in the detection of visual deficits in public schools because very little has been done to identify and treat the causes of low visual acuity in children, a health problem related to the educational status in Brazil²⁰. It is important to emphasize the need for campaigns of visual acuity assessment during the first school year with the purpose of detecting possible eye problems, so that they can be corrected, and preventing their worsening, since socioeconomic and cultural conditions make it difficult for children to have access to an ophthalmologic examination²¹. It is worth highlighting that the need for such actions was reinforced by a study conducted in Brazil about the major causes of blindness and low vision, which showed that 59% of eye diseases are preventable or treatable²².

CONCLUSION

The present study showed that 34.8% of the students assessed had impaired visual acuity and, among these, only 75% had satisfactory academic performance compared with the percentage of satisfactory academic performance found for students with normal VA (89.5%).

There is a huge difficulty of access to preventive measures aimed at eye health partly because of insufficient coverage of the health system in Brazil and the lack of public awareness about the importance of prevention by means of early ophthalmologic evaluation. As vision problems may affect children's learning process and socialization, this screening and subsequent referral of students with impaired VA contributed to better individual academic performance and, as a consequence, better performance of the whole class, in addition to enabling the improvement of the students' quality of life.

Thus, the present study highlights the need for preventive measures aimed at eye health in the early stages of life, encouraging campaigns for the detection and prevention of vision problems and thus allowing a better investigation of visual impairment in public schools.

Conflict of interest:No conflicts of interest declared concerning the publication of this article.

REFERENCES

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*

Correspondência: Rua Mamoré, 495 - São Mateus - Juiz de Fora, MG. CEP: 36025-280

Publication Dates

• Publication in this collection
  12 Nov 2010
• Date of issue
  2010

History

• Received
  01 Dec 2009
• Accepted
  16 May 2010