Characteristics of Visually Impaired Children Aged Below 4 Years in Two Public Tertiary Hospitals in Selangor, Malaysia

Authors: Knight VF, Muhd Khairi N, Omar R, Ramlee A, Mohd Isa M

Affiliation: Faculty of Health Sciences, Universiti Kebangsaan Malaysia

Published: Malaysian Journal of Public Health Medicine, 2018, Special Volume (1): 18–25

Last reviewed: March 2026

Background and Context

Visual impairment in early childhood represents a significant public health concern due to its profound impact on a child’s overall development. The visual system undergoes its most critical period of maturation during the first few years of life, and disruptions during this sensitive window can have lasting consequences for visual, motor, cognitive, and psychosocial functioning. Children who develop visual impairment before the age of 4 years are at particular risk, as this period coincides with fundamental milestones in visual processing, hand-eye coordination, spatial awareness, and language acquisition — all of which are heavily dependent on intact visual input.

Globally, it is estimated that approximately 90% of paediatric visual impairment is amenable to intervention through early detection and treatment at primary, secondary, and tertiary levels of eye care. The leading causes of childhood visual impairment vary by setting: in high-income countries, cerebral visual impairment (CVI) and optic nerve anomalies predominate, while in lower-income settings, conditions such as congenital cataract, corneal scarring from vitamin A deficiency, and retinopathy of prematurity are more prevalent. Malaysia, as an upper-middle-income country with a well-developed healthcare system, occupies an intermediate position, with a cause profile that reflects both adequate neonatal care and remaining gaps in early detection.

In Malaysia, child healthcare is delivered through a network of public hospitals, community health clinics, and private healthcare facilities. Visual screening for children is incorporated into the national child health programme, though the age at which children receive comprehensive eye examinations and the capacity for specialist paediatric ophthalmology assessment vary by region. Selangor, as the most populous state in Malaysia with a population exceeding 6 million, is served by multiple public tertiary hospitals with dedicated ophthalmology departments capable of providing subspecialty paediatric eye care.

Study Design and Methods

This study employed a cross-sectional retrospective design, reviewing the ophthalmology clinic records of all children aged below 4 years who presented to two public tertiary referral hospitals in Selangor over a 5-year study period. The hospitals were selected as major referral centres receiving both primary presentations and secondary referrals from across the state and neighbouring regions.

Visual impairment was defined and classified according to the World Health Organisation system based on presenting visual acuity in the better eye: moderate visual impairment (visual acuity worse than 6/18 but equal to or better than 6/60), severe visual impairment (worse than 6/60 but equal to or better than 3/60), and blindness (worse than 3/60). This classification system is widely used in epidemiological studies of visual impairment and facilitates international comparisons.

The prevalence of visual impairment was calculated based on presenting visual acuity — that is, the visual acuity measured with whatever correction (spectacles or contact lenses) the child was already using, if any. Cases were then further differentiated according to the specific cause of visual impairment as diagnosed through clinical examination. The anatomical site of pathology and the aetiological classification were recorded for each case.

Clinical Significance of Early Detection

The distinction between treatable, preventable, and untreatable causes of childhood visual impairment carries direct implications for public health strategy. Treatable causes — such as congenital cataract, refractive errors, and certain forms of strabismic amblyopia — can be addressed through surgical intervention, optical correction, or amblyopia therapy, provided they are identified during the critical period of visual development. Preventable causes include conditions linked to modifiable risk factors such as maternal nutrition, perinatal care quality, and neonatal screening programmes. Understanding the proportional contribution of each cause category in the Malaysian context is essential for allocating healthcare resources effectively.

A subsequent study conducted at a tertiary eye care centre in Kuala Lumpur in 2020 found that among 2,460 children aged 7 years and below seen at the paediatric ophthalmology clinic, 22.3% (549 children) presented with visual impairment. Of the visually impaired children, 73.2% were diagnosed with blindness at presentation, and 62.8% of these were under 1 year old. Cerebral visual impairment accounted for 24.2% of cases, followed by congenital cataract at 16.6% and retinoblastoma at 6.2%. Importantly, 38.4% of causes were assessed as treatable and 31.1% as preventable, meaning that more than half of childhood visual impairment in the study could potentially have been addressed through timely intervention.

Implications for Malaysian Child Eye Health Policy

The findings from this study and related Malaysian research support several policy priorities. Universal newborn eye screening, when systematically implemented, can detect conditions such as congenital cataract and retinoblastoma at stages where treatment outcomes are significantly better. The integration of formal visual assessment into the existing national child health schedule, with clear referral pathways to ophthalmology services, represents a cost-effective approach to reducing the burden of avoidable childhood visual impairment.

Training of primary healthcare providers, including community health nurses and general practitioners, in basic paediatric eye assessment techniques can expand the capacity for early detection in community settings. Parent education regarding developmental red flags — such as absence of the social smile, failure to fixate and follow objects, nystagmus, or a white pupillary reflex — can facilitate earlier presentation to specialist services.

Limitations

As a hospital-based retrospective study, the findings may overestimate the severity profile of childhood visual impairment relative to the general population, since tertiary hospitals receive referrals of more complex and severe cases. Children with mild visual impairment who are managed at primary or secondary care levels, or who remain undiagnosed, would not be captured. The retrospective design is also subject to the limitations of medical record quality and completeness. The study population was drawn from Selangor, an urbanised and relatively well-resourced state, and findings may not be generalisable to less developed or more remote regions of Malaysia where access to paediatric ophthalmology services is more limited.