INTRODUCTION

Major epidemiological studies on the causes of low visual acuity, with a focus on several types of ocular diseases considered in isolation or in combination, or the evaluation of overall aspects of these diseases, are common in the literature. These studies serve as the foundation for various eye care policies^{( 1 - 4 )}.

However, few epidemiological studies have elucidated more specific aspects which assume greater importance when addressing more restricted population groups^{( 5 - 7 )}.

This is mainly the case in groups of individuals with ocular morbidities that live in geriatric day-care clinics. In addition to ocular morbidities, associated systemic diseases may limit or even prevent the access to outpatient care for evaluation or treatment of these morbidities. Even a simple refraction examination, with prescription of corrective lenses, becomes an almost inaccessible treatment option. These incapacitating conditions are limitations that outweigh the eye complications, particularly when social and family aspects are involved^{( 1 , 8 , 9 )}.

This study aimed to identify the main causes of low visual acuity and systemic morbidities that may limit or preclude the access to ophthalmologic examination in inpatients of geriatric clinics in Rio de Janeiro.

METHODS

This cross-sectional study evaluated patients from three private day-care geriatric clinics in Rio de Janeiro between January 2010 and January 2011. All participants (or their legal guardian, where appropriate) signed an informed consent form. The refusal of individuals or family membersin participating in the study was respected. This study was approved by the Research Ethics Committee of the Universidade Federal Fluminense.

All patients with a visual acuity of ≤20/200 and without optical correction in either eye were initially included in the study.

The study excluded individuals who refused to participate and those having mental disabilities that could limit the performance of ophthalmologic examinations.

Initially, 187 individuals enrolled in the study, and after the application of the inclusion and exclusion criteria, 118 individuals effectively enrolled. Six individuals whose degree of mental retardation precluded the assessment of visual acuity, considering the impossibility of social interaction, were excluded. Of the 187 individuals initially enrolled, 63 had a visual acuity of >20/200 and were not included in the study.

Systemic morbidities were also listed. Disabling morbidities were considered to be those that precluded the realization of evaluations during outpatient medical and ophthalmologic consultations; people with physical or mental disabilities were included in this group. All medical information related to morbidities was collected through interviews and assessment of patient documents as well as medical records maintained in the geriatric clinic.

Systemic morbidities were recorded and classified into the following subgroups:

Some common systemic morbidities were assigned to older people and the remaining morbidities were allocated in the subgroup designated "others."

Ophthalmologic examination was performed in the hospitalization rooms of the geriatric clinic. Visual acuity was measured using Snellen's chart (Optik Inc., São Paulo, Brazil), a test box of spherical and cylindrical lenses with universal test frames, retinoscope and indirect ophthalmoscope (Welch Allyn Inc., Skaneateles Falls, USA), illuminated magnifier (Estek Inc., São Paulo, Brazil), contact tonometry (Tonopen, Reichert Inc., Depew, USA), anesthetic eye drops (Anestalcon, Alcon Inc., São Paulo, Brazil), and pupil dilation using tropicamide eye drops 1% (Latinofarma, Inc. - São Paulo, Brazil). Some criteria were used (equipment portability, lack of slit-lamp for ocular microscopy, and failure of immediate referral to more sophisticated complementary exams) for the definition of the etiological groups of specific ocular diseases to simplify the ophthalmologic examinations. The causes of low visual acuity reported herein are those that originated directly from visual impairment, and other concurrent eye diseases were not considered.

The more common causes of low visual acuity among older people were categorized and less common causes were allocated to the category designated as "others."

Epidemiological data including gender, age, systemic morbidity, and the causes of low visual acuity were recorded and evaluated as a unilateral or bilateral characteristic.

With regard to the statistical tests involved, a nonparametric chi-square test and Fisher's Exact test were used with a significance level of 5% (gender and causes of low visual acuity were analyzed using frequencies and percentages and displayed through contingency tables). Epidemiological data regarding age were analyzed using unpaired Student's t test and means and standard deviations.

A total of three tables covering all study groups evaluated (total population, individuals with low visual acuity, and individuals with low visual acuity combined with mobility disabilities) were analyzed with these statistical tests to correlate the data with each other.

The causes of low visual acuity and their characteristics are listed below:

RESULTS

A total of 118 individuals presented a visual acuity of <20/200 due to various causes, and among them, a subgroup of 57 patients presented systemic disabling morbidities (Table 1).

Table 1 shows that the epidemiological data were not significant after statistical analysis. Table 1 describes the three study groups according to gender and age. One group involved all the individuals evaluated, another group involved individuals with low visual acuity, and a third group involved those with low visual acuity and disabling systemic morbidities. The chi-square and Student's t tests were used to compare gender and age between these three groups, respectively. Although the frequencies, means, and standard deviations were different, statistical tests were not significant, indicating statistical similarity.

Table 2 shows the details of the group with low visual acuity. Of the 118 individuals with low visual acuity, 27.96% had cataract, and 26.27% had refractive errors. These data were significant in comparison with the set of other comorbidities.

Table 3 describes the study group with low visual acuity and locomotor disabilities. Of the 57 individuals with systemic disabling morbidities, 36.84% suffered from refractive errors and 21.05% had cataract. These data were also significant when compared with the set of other comorbidities.

All cases with refractive errors were corrected with significant improvement of visual acuity and evident satisfaction.

DISCUSSION

Vulnerable populations that have restricted mobility and limited access to specialized eye care need special attention with actions aimed at circumventing these difficulties. Epidemiological characteristics including age, gender, and ethnicity, were analyzed in this study. However, no significant differences in these characteristics were observed between the study groups. Moreover, no statistically significant difference in the epidemiological data was observed for individuals with disabling systemic morbidities^{( 10 - 12 )}.

Whitson et al. observed that individuals experiencing visual impairment along with cognitive disabilities are at high risk of disability, and each of these conditions contributes additively to the risk of disability among older people^{( 8 )}

Araújo et al. evaluated older people in geriatric care facilities and observed that 60% were women and 40% were men. In this study, 56% of the study group were men and 44% were women. The mean age in the present study was 69 years, in contrast to the 82 years reported by Araújo et al. The present study was performed in private geriatric clinics, in contrast to the study by Araújo et al.^{( 12 )}.

In the present study, the etiologies of the subcategories of systemic morbidities reflect a variety of causes, which often partially restrict the mobility capacity of individuals. In addition, 38 patients were bedridden and unable to remain upright (19.3% of the study group). In this subgroup, the individuals with refractive errors and who achieved optical correction had the highest satisfaction in terms of medical care.

Most of the reported etiologies involving visual acuity deficits among older people include refractive errors, cataracts, age-related macular degeneration, and glaucoma^{( 3 , 4 , 13 )}. Limburg et al. found that 43%-88% of the causes of blindness among individuals aged ≥50 years in Latin America were curable and were mainly caused by cataract and refractive errors^{( 13 )}.

In this study, low visual acuity was observed in 64 patients (54.2%). This would be a significant rate to justify the visual complaints. However, 14 of these patients (11.8%) were already using correction glasses previously prescribed. Two of these causes are easier to correct, one of a surgical nature (cataracts) and the other involving prescription glasses (refractive errors).

This study addressed a population with great difficulty in accessing ophthalmic outpatient services. This fact underscores the importance of conducting this type of ophthalmologic examination in geriatric institutions because, even in private clinics, the access to ophthalmologic examination is limited for these individuals considering the complexity of the equipment necessary for home-based eye care^{( 10 )}.

Of note, even among the individuals with no disabling ambulation problems (63 individuals), some patients benefited from the eye consultation, by receiving a prescription of glasses and correction of refractive errors (13 subjects), because of a simple social problem: the family members could not provide follow-up support for home-based medical care^{( 14 , 15 )}.

The present study showed that many individuals presented with systemic diseases that could lead to low visual acuity, including diabetes and systemic diseases, which interfere with ambulation and limitthe patient's visit to an eye care service facility^{( 11 , 16 , 17 )}.

Therefore, periodic ophthalmologic assessments, particularly those of chronic ocular diseases, in geriatric clinics are essential to improve the quality of life of individuals, even of those who are bedridden and experience unfavorable cognitive conditions^{( 13 , 18 , 19 )}.

Despite the value of this epidemiological analysis, the present study has some limitations, including the small sample size evaluated and the evaluation of patients in a single municipality, despite having a large population(12,20). However, this limitation has also been observed in other studies that evaluated this social group. In this respect, Araújo et al. evaluated older people in two clinics, with a total of 25 individuals in each clinic^{( 12 )}.