Epidemiology, clinical profile, and pattern of refractive error in newly diagnosed cases of refractive error in pediatric population visiting a tertiary eye care center

Vimal Krishna Rajput; Naren Shetty; Pritish Raut

doi:10.4103/jcor.jcor_9_20

ORIGINAL ARTICLE

Year : 2021 | Volume : 9 | Issue : 2 | Page : 67-70

Epidemiology, clinical profile, and pattern of refractive error in newly diagnosed cases of refractive error in pediatric population visiting a tertiary eye care center

Vimal Krishna Rajput¹, Naren Shetty², Pritish Raut³
¹ Department of Pediatric Ophthalmology and Neuro-Ophthalmology, Narayana Nethralaya-3, Bengaluru, Karnataka, India
² Department of Cataract and Refractive Services, Narayana Nethralaya-3, Bengaluru, Karnataka, India
³ Department of Community Medicine, DVVPF's Medical College, Ahmednagar, Maharashtra, India

Date of Submission	07-Feb-2020
Date of Decision	13-May-2021
Date of Acceptance	17-May-2021
Date of Web Publication	31-Jul-2021

Correspondence Address:
Vimal Krishna Rajput
Department of Pediatric Ophthalmology and Neuro-Ophthalmology, Narayana Nethralaya-3, 37 Castle Street, Ashok Nagar, Bengaluru - 560 025, Karnataka
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jcor.jcor_9_20

Abstract

Purpose: This study aimed to evaluate the epidemiology, clinical profile, and pattern of refractive error in newly diagnosed cases in children visiting a tertiary care eye center in southern India. Materials and Methods: This prospective study was conducted on 367 children, ≤15 years of age, with significant refractive error who visited our tertiary eye care hospital over a period of 1 year. Every child underwent detailed ocular examination. Significant refractive error was defined as myopia of ≥−0.75 diopter (D), hypermetropia of more than +2 D, and astigmatism of more than 0.75 D. Descriptive statistics were computed for better and the worse eye. Statistical tests were applied between the worse and better eyes using Chi-square test. Results: A total of 367 children (38.8%) were diagnosed for the first time of having refractive error. Only 146 (39.8%) children presented with visual complaints. With respect to the vision in the worse eye, 65.9% (n = 240) had moderately subnormal vision. There was no statistically significant difference (P = 0.057) between age distribution and visual acuity in the worse eye. Two hundred and thirty-eight children (64.9%) had significant astigmatism as compared to 161 myopic (43.9%) children. There was a statistically significant difference between reasons of visit and different age groups. Conclusions: Astigmatism was the most prevalent refractive error and uncorrected astigmatism the most significant amblyogenic factor. Since majority of children, especially in the younger age group, present with nonvisual complaints, involvement of pediatricians and parents will help us to reduce morbidity due to uncorrected refractive error and amblyopia.

Keywords: Amblyopia, new cases, nonvisual complaints, refractive error

How to cite this article:
Rajput VK, Shetty N, Raut P. Epidemiology, clinical profile, and pattern of refractive error in newly diagnosed cases of refractive error in pediatric population visiting a tertiary eye care center. J Clin Ophthalmol Res 2021;9:67-70

How to cite this URL:
Rajput VK, Shetty N, Raut P. Epidemiology, clinical profile, and pattern of refractive error in newly diagnosed cases of refractive error in pediatric population visiting a tertiary eye care center. J Clin Ophthalmol Res [serial online] 2021 [cited 2023 Mar 24];9:67-70. Available from: https://www.jcor.in/text.asp?2021/9/2/67/322797

Refractive errors are the second major reason behind blindness in India after cataract and therefore one of the most common reasons for patients to visit an ophthalmologist. Over a quarter of the outpatient attendance at all eye clinics and hospitals is due to refractive errors.^[1] The prevalence of blindness in children in India is estimated to be 0.8/1000 children in the age group of 0–15 years,^[2],[3] though no population-based nationwide survey has been undertaken yet. At present, there are an estimated 270,000 blind children in India. Among children outside blind schools, refractive errors are important causes of visual impairment and blindness.^[2],[3] Poor vision in childhood affects the performance in school and also has a negative influence on their development and maturity.^[4] Since most of the school-going children can adjust to poor eyesight in different ways, for example, sitting closer to the blackboard, holding their books close to their eyes, or squeezing their eyes; they do not realize that they are suffering from the ocular disability.^[5]

Amblyopia implies low vision in one or both eyes due to abnormal development of vision in infancy or childhood. It affects up to 4% of children aged up to 7 years and can be amenable to treatment if detected early enough.^[6] Hence, early and correct diagnosis and intervention is necessary to prevent the vision loss resulting from amblyopia.

The objective was to study the epidemiology, clinical profile, and pattern of refractive error among newly diagnosed cases in pediatric population (≤15 years of age) visiting a tertiary eye care center in southern India.

Materials and Methods

This hospital-based prospective study was conducted at a tertiary eye care center located in Central Bangalore (Karnataka, South India) over a period of 1 year from August 2016 to July 2017. The study was approved prior by the institutional ethics and review board and adhered to the provisions of the Declaration of Helsinki for research on human participants. Children ≤15 years of age with refractive error were considered for the study. The following children were excluded:

Those with previous history of use of glasses
Those with previous history of ocular surgery or trauma
Children who were not cooperative for vision or refraction
Those with congenital anterior segment abnormalities
Those who were diagnosed with spasm of accommodation. Enrollment process is summarized in [Figure 1].

Figure 1: Summary of enrollment process – flow diagram

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Every child underwent a standard routine examination. History pertaining to presenting complaints and past ocular problems and treatment, history of medical or surgical treatment, and family history were obtained. Visual acuity was measured at 6 m by an optometrist, using a digital vision logarithm of the minimum angle of resolution chart, and was recorded as the smallest line read with one or no errors after converting it to Snellen equivalent. Both the eyes were tested in tandem. Cover test was performed for near (33 cm) and distance (6 m) and tropias were classified as esotropia, exotropia, or vertical deviation and the degree of tropia was measured using the prism bar cover test.

Pupils were dilated with two drops of 1% cyclopentolate and one drop of 0.8% tropicamide + 5% phenylephrine, administered 5 min apart. Light reflex and pupil dilation were evaluated after 45 min. Refraction was performed by an optometrist, regardless of visual acuity using a streak retinoscope. Children with uncorrected visual acuity of 6/9 or worse in either eye underwent subjective refraction. The anterior segment was examined using a slit lamp, and the fundus was evaluated with the help of an indirect ophthalmoscope.

Significant refractive error was considered to be myopia of ≥−0.75 diopter (D), hypermetropia of more than +2 D, and astigmatism cylindrical error of more than 0.75 D.^[7] Amblyopia was defined as unilateral or bilateral subnormal vision, at least two lines less than normal or two lines less than the fellow eye in unilateral cases.^[6] The degree of subnormal vision was categorized as mild (better than 6/12), moderate (6/12–6/36), and severe (worse than 6/36).^[6]

Data collected were entered in an Excel format. Descriptive and analytical statistics were computed. The statistical analysis was done with the SPSS version 22 (IBM Corporation, SPSS Inc., Chicago, IL, USA). Descriptive statistics with frequency and mean ± standard deviation were computed for the worse and better eyes. The eye with better vision was considered as “better eye.” In case the vision was the same in both the eyes, the eye with higher spherical error was considered the worse eye. Statistical tests were applied between the worse and better eyes using Chi-square test for proportions with 95% confidence interval.

Results

A total of 946 children were screened during the study period, of which 367 were freshly detected cases, accounting for 38.8% of new cases. The mean age was 12.1 (4.5–15 years), with 207 (56.4%) boys and 160 (43.6%) girls.

Reason for visit

Although 39.8% of children (n = 146) complained of blurring of vision, 60.2% (n = 221) were diagnosed due to nonvision-related complaints. These included routine eye examination, headache, squint, allergic eye disease, and ocular surface infections. [Table 1] shows that there was a statistically significant difference between reasons of visit to different age groups. Visual complaints were most often stated by children in age groups >10 years (n = 85). Children younger than 5 years were diagnosed on either routine eye examination or during examination for allergic eye disease (88.5% had nonvision-related complaints).

Table 1: Comparison of age group with reason

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Better eye

Forty-three children (11.8%) had 6/6 vision at presentation. One hundred and seventy children (46.8%) presented with moderately subnormal vision. The most common refractive error was astigmatism, accounting for 53.4%, followed by myopia (30%) and hypermetropia (3.5%). There was a statistically significant difference (P = 0.012) between age distribution and visual acuity in the better eye, indicating a significantly higher prevalence of refractive error in children 5–10 years. There was no statistically significant difference (P = 0.13) between gender distribution and visual acuity in the better eye.

Worse eye

With respect to the vision in the worse eye, most of them had moderately subnormal vision, 240 (65.9%). Around one-tenth (9.9%) of children presented with vision poor than 6/38. Here also, the most common refractive error was astigmatism, accounting for 64.6%, followed by myopia (44.2%) and hypermetropia (5.4%). There was no statistically significant difference (P = 0.57) between age distribution and visual acuity in the worse eye.

Refractive error

One hundred and sixty-one children (44.2%) had myopia. The prevalence of myopia increased with increasing age group, i.e., 42.4% belonged to >10 years of age group. Out of two hundred and thirty-eight (64.6%) children who had astigmatism, majority of them were seen in age group 5–10 years (56.1%) with almost equal frequency in <5 and >10 years' age group. A similar pattern was seen in hypermetropic children.

Associated diseases

Eighty-two out of 367 children (22.3%) had other associated ocular conditions. The most prevalent was amblyopia, accounting for 69.5% of cases (58.5% refractive and 11% strabismic). Around 20% of children were diagnosed with tropia (n = 16). Of these 16 children, 13 had comitant squint and 3 were incomitant (1 – Brown's syndrome and 2 – Duane retraction syndrome). The “other” group which included allergic eye diseases, optic nerve head drusen, keratoconus, and color blindness accounted for 11% of cases.

[Table 2] highlights the characteristics of refractive amblyopic children. Sixty percent of 48 amblyopic children belonged to 5–10 years' age group. On comparing the reasons of visit, 27% presented with visual complaints and the rest 77% had complaints not specific to vision. Most of them had moderately subnormal vision (72.9%). This pattern was similar to that seen in the entire cohort. With respect to the refractive error, 37 children (77.08%, out of 48 amblyopic children) had only astigmatism, 2 had high hypermetropia with high astigmatism, and 8 had high myopia with high astigmatism.

Table 2: Characteristics of refractive amblyopic children

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Discussion

After a thorough search, we could not find any study on new cases of refractive error in pediatric population. To the best of our knowledge, this is the first hospital-based study on this issue in Indian population.

In our study, the prevalence of refractive errors was slightly higher in males as compared to females (56.4% vs. 43.6%), though the difference was statistically insignificant. Similar results were reported in hospital-based studies done by Rai et al. in Nepal and Mittal et al. in Uttarakhand.^[8],[9] Population-based studies (Dulani and Dulani in Jaipur, Pavithra et al. in Bangalore, and Prema in Tamil Nadu) have reported higher affection of females.^{[10],[11],[12]} Mittal et al. postulated that the possible cause of this difference may be ignorance toward the needs of female child or may be due to the social stigma associated with spectacle usage in females.^[9] Mittal et al. found majority cases of mildly low vision, <6/12 in their series. However, they had included all cases of refractive errors, old as well as new. The grade of low vision was 48.3% (mild), 33.8% (moderate), and 17.9% (severe) as compared to 24.2%, 65.9%, and 9.9%, respectively, in our series.^[9] They found 41.2% of patients with myopia, 11.8% with hypermetropia, and 47% with astigmatism.^[9] The higher prevalence of hypermetropia was due to the cutoff of 0.5 D. However, as we had followed the cutoff guidelines as proposed by Sheeladevi et al., we found the prevalence of hypermetropia to be quite lower (5.4%). When studying the association of type of significant refractive errors with age, we also found an age-related shift from hypermetropia in young children to myopia in older children, similar to the studies by Murthy et al., Kalikivayi et al., and Mittal et al.^{[9],[13],[14]}

The cumulative incidence of amblyopia is estimated to be 2%–4% in children aged up to 7 years.^[15] A relatively higher prevalence was observed by Mittal et al. (7.1%) and Gupta et al. (8.6%) in their retrospective study on profile of amblyopia in school-going (5–15 years) children at a state-level referral hospital in Uttarakhand.^[9],[16] The incidence in our study was 13%. This is probably because ours was a hospital-based study. Astigmatism was found to be the most common refractive error resulting in amblyopia, similar to previous studies.^{[16],[17],[18]} In a study by Jamali et al., of 52 Iranian children with amblyopia, 81% had significant refractive errors, 11% had strabismus, and 8% had both.^[18] We found these rates to be 66%, 22%, and 12%, respectively. Daigavane et al^[19] in their study on Indian population also found 13 children to have amblyopia 53% were refractive and 23% were strabismic. In a study by Mittal S et al^[9], the numbers were 60.71% and 39.29%, respectively. In our study, 20% of children were diagnosed with tropia, 69.2% were esotropic, and 30.8% exotropic. Mittal et al. also found esotropia to be the most common ocular misalignment (62.5%. vs. 37.5% exotropia).^[9]

No prior study has studied the reason for consulting an ophthalmologist in children. A majority, i.e., 60.2%, was diagnosed due to nonvision-related complaints. Visual complaints were most often stated by children in age groups >10 years (n = 85). Children younger than 5 years were diagnosed on either routine eye examination or during examination for allergic eye disease (88.5% had nonvision-related complaints). Hence, it is essential that all children at least by the age of 5 years should undergo a detailed eye checkup.

Conclusions

Most of the children with refractive error presented with moderate decrease in visual acuity (6/15–6/36). Astigmatism was the most common type of refractive error followed by myopia and hypermetropia. Most of the children, especially <5 years of age, are diagnosed during routine eye examination or when presented with nonvisual complaints. The most common amblyogenic factor is uncorrected refractive error, uncorrected astigmatism being the most common. On the one hand, it is essential to increase the efforts to educate and sensitize parents regarding the importance of early visual testing and amblyopia, while on the other hand, it must be made compulsory for the child to get eyes checked before taking admission in schools.

Since this was a hospital-based study, larger population-based studies are needed to further validate the mass education measures that are necessary to prevent and treat amblyopia.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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