Vision develops rapidly during the first decade of life, and any interruption of this process can have lifelong consequences for education, employment, and quality of life. Ocular morbidity in the paediatric age group is therefore of disproportionate public-health importance: disease that would be a minor inconvenience in an adult can, in a child, drive amblyopia, permanent visual deprivation, and impaired psychosocial and scholastic development.[2] An estimated 39 million people are blind worldwide, of whom approximately 1.4 million are children younger than 14 years [INSERT verified WHO reference - global childhood blindness magnitude]. A substantial share of this burden is avoidable: in surveys of children younger than 15 years the prevalence of blindness has been reported at around 0.17%, of which roughly one-third is attributable to treatable refractive error and the remainder to other preventable causes.[1] The importance of childhood ocular disease is amplified in low- and middle-income settings. In India, preventable and treatable causes such as uncorrected refractive error and cataract contribute to the majority of childhood visual impairment, and a large proportion of people who are blind lose their sight early in life.[1] Uncorrected refractive error is particularly consequential because it is common, easily diagnosed, and readily corrected, yet frequently goes undetected until it interferes with schooling; it is also associated with asthenopia and recurrent headache in schoolchildren.[3] Timely detection and correction can prevent both the immediate educational handicap and the longer-term risk of amblyopia.[14] A large body of Indian evidence has quantified ocular morbidity in community and school settings. School-based surveys have reported overall ocular morbidity prevalences ranging from roughly 13% to 29%, with refractive error consistently the leading disorder, followed variably by allergic conjunctivitis, strabismus, and lid or lacrimal disease.[4][5][6] Early Indian appraisals of school eye health and paediatric ocular problems established this pattern decades ago,[15][16] and studies from northern India in particular have documented a high prevalence of ocular morbidity and visual impairment among school-going children.[4] These community datasets are invaluable for estimating population prevalence and for planning screening, but they capture a different population from the one that presents to hospital: children who reach a tertiary outpatient department have typically been referred or self-selected because of symptoms, so the observed spectrum of disease reflects care-seeking and referral patterns rather than population prevalence.[7][8] Hospital-based series from tertiary centres therefore complement community surveys by describing what actually presents for specialist care, informing service planning, training, and resource allocation. Such series exist from eastern and northern India,[7][8] and refraction-focused hospital studies from the wider region confirm that uncorrected refractive error dominates paediatric presentations and that a substantial fraction of affected children already have measurable visual impairment at first contact.[9] Comparatively little has been published from tertiary centres in southern India, and the pattern of disease is known to vary with geography, climate, and socioeconomic conditions - factors that shape, for example, the local burden of vernal keratoconjunctivitis and ocular trauma.[10] Robust regional data are needed to tailor eye-health services and to prioritise interventions such as school vision screening.[10] We therefore undertook a hospital-based cross-sectional study at a tertiary care centre in Ballari, northern Karnataka, to describe the pattern of ocular morbidity among children younger than 15 years attending the ophthalmology outpatient department, and to examine how this pattern varies by age and sex. We hypothesised that refractive error would be the most frequent morbidity across age groups, consistent with the wider Indian literature, and that the distribution of the remaining disorders would reflect the local referral population. The specific objectives were: (i) to determine the pattern and relative frequency of different ocular disorders among paediatric patients (age <15 years); and (ii) to describe the distribution of these disorders across age and sex.

Study design and setting This was a hospital-based, descriptive, cross-sectional study conducted in the Department of Ophthalmology (Unit 2 outpatient department), Vijayanagara Institute of Medical Sciences/Ballari Medical College and Research Centre, Ballari, Karnataka, India - a tertiary care teaching hospital serving a predominantly semi-urban and rural population in northern Karnataka. Data were collected consecutively over an 18-month period from July 2022 to December 2023. The study is reported in accordance with the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidance for cross-sectional studies. Participants and eligibility All patients younger than 15 years who presented to the outpatient department during the study period with any ocular complaint or disorder in one or both eyes, and whose parent or guardian consented to participation, were eligible for inclusion. Patients aged 15 years or older, and those whose guardian declined consent, were excluded. Every consecutive eligible child was enrolled; no age, sex, or diagnostic subgroup was preferentially sampled. Sample size The sample size was based on an expected prevalence of ocular morbidity of 21.2%, taken from a previous Indian study, using the formula n = Z²P(1-P)/d², with Z = 1.96 for 95% confidence and an absolute permissible error. On the basis of the anticipated outpatient attendance of children in Unit 2 over 18 months, a target of 350 patients was set, and 350 consecutive eligible children were enrolled and analysed. Clinical examination and data collection Each child underwent a standardised ophthalmic assessment by an ophthalmologist, with refraction performed by an optometrist. The protocol comprised: anterior segment examination by torchlight; visual acuity assessment using an age-appropriate Snellen chart; colour vision testing with Ishihara pseudo-isochromatic plates; and slit-lamp biomicroscopy. Cycloplegic refraction, dilated fundus examination, lacrimal syringing and probing, intra-ocular pressure measurement, visual field testing, and orthoptic (squint) evaluation were performed where clinically indicated. Age-appropriate methods of visual acuity testing were used for younger and preverbal children in line with published evidence-based approaches.[14] Findings for each participant were recorded on a structured study proforma capturing demographic details, presenting complaint, examination findings, and the final diagnosis. Definitions and classification Each child was assigned to a single principal ocular morbidity category on the basis of the clinical diagnosis. Categories were: refractive error; vernal keratoconjunctivitis; conjunctival disorders (other conjunctival disease, including infective conjunctivitis); lacrimal drainage disorders (including acute and chronic dacryocystitis and congenital nasolacrimal duct obstruction); squint (strabismus); developmental cataract; lid disorders; ocular trauma; ptosis; and a miscellaneous group for disorders not otherwise classified. Vernal keratoconjunctivitis was diagnosed clinically on the basis of characteristic symptoms and signs; refractive error was defined by cycloplegic refraction where performed. Diagnostic categories for cataract, lacrimal, and allergic disease followed standard clinical criteria.[11][12][13] Participants were grouped into three age bands - 0-5, 5-10, and 10-15 years - for stratified analysis. Statistical analysis Data were compiled from the study proformas and analysed descriptively. Categorical variables (age band, sex, and morbidity category) are summarised as frequencies and percentages, with the relevant denominator stated alongside each proportion. Morbidity frequencies are presented overall and stratified by age group and sex. Because the study was descriptive and every diagnosis was mutually exclusive, no inferential hypothesis testing was pre-specified; where the authors wish to test associations (for example, between sex and morbidity category), a chi-square test with an exact p-value and effect estimate should be added. No data were imputed; analyses are based on complete records for the enrolled children. Ethics The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Ethics Committee of Ballari Medical College and Research Centre/VIMS, Ballari. Informed consent was obtained from the parent or legal guardian of every participating child, and age-appropriate assent was sought where feasible; participant confidentiality was maintained throughout.

Participant characteristics During the 18-month study period, 350 children younger than 15 years were evaluated. The 5-10-year age band was the largest, comprising 133 of 350 children (38.0%), followed by the 10-15-year band (122/350, 34.9%) and the 0-5-year band (95/350, 27.1%) (Table 1). Boys outnumbered girls: across the detailed age- and sex-stratified data, 202 of 350 children (57.7%) were male and 148 (42.3%) were female, a male-to-female ratio of 1.36:1 (Table 1). Male predominance was present in every age band. Table 1. Age and sex distribution of paediatric patients (N = 350). Age band (years) Male, n Female, n Total, n % of total 0-5 50 45 95 27.1 5-10 80 53 133 38.0 10-15 72 50 122 34.9 Total 202 148 350 100 Percentages are of the total sample (N = 350). Sex counts are derived by summing the age-stratified cross-tabulations. The source aggregate gender table recorded 206 male and 144 female; this differs by four patients from the age-stratified totals shown here and should be reconciled by the authors. Overall pattern of ocular morbidity Refractive error was the single most common ocular morbidity, diagnosed in 123 of 350 children (35.1%). This was followed by vernal keratoconjunctivitis in 82 children (23.4%) and other conjunctival disorders in 47 (13.4%). Together, refractive error and vernal keratoconjunctivitis accounted for 205 of 350 children (58.6%). Lacrimal drainage disorders were present in 25 children (7.1%), squint in 19 (5.4%), developmental cataract in 17 (4.9%), lid disorders in 15 (4.3%), and ocular trauma in 14 (4.0%). Ptosis and miscellaneous disorders each accounted for 4 children (1.1%) (Table 2). Blurring of vision was the most frequently reported presenting symptom. Ocular morbidity n % of 350 Refractive error 123 35.1 Vernal keratoconjunctivitis 82 23.4 Conjunctival disorders 47 13.4 Lacrimal drainage disorders 25 7.1 Squint (strabismus) 19 5.4 Developmental cataract 17 4.9 Lid disorders 15 4.3 Ocular trauma 14 4.0 Ptosis 4 1.1 Miscellaneous 4 1.1 Total 350 100 Table 2. Distribution of ocular morbidity among paediatric patients, overall (N = 350). Each child was assigned a single principal morbidity category; categories are mutually exclusive. Morbidity by age group Refractive error was the leading morbidity in all three age bands and was proportionally highest among children aged 5-10 years (47/133, 35.3%) and 10-15 years (43/122, 35.2%), and slightly lower among those aged 0-5 years (33/95, 34.7%) (Table 3). Vernal keratoconjunctivitis showed a marked age gradient, rising from 12 of 95 children (12.6%) in the 0-5-year band to 36 of 133 (27.1%) at 5-10 years and 34 of 122 (27.9%) at 10-15 years. Conjunctival disorders were relatively more frequent in the youngest band (17/95, 17.9%) than in the older bands (11-12%), as were lacrimal drainage disorders (10/95, 10.5% at 0-5 years versus about 6% thereafter). Developmental cataract was likewise proportionally commonest in the 0-5-year band (7/95, 7.4%). Ocular trauma was distributed across all age groups (3-5% per band). Table 3. Ocular morbidity by age band, n (% of age-band total). Ocular morbidity 0-5 y (n=95) 5-10 y (n=133) 10-15 y (n=122) Refractive error 33 (34.7) 47 (35.3) 43 (35.2) Vernal keratoconjunctivitis 12 (12.6) 36 (27.1) 34 (27.9) Conjunctival disorders 17 (17.9) 15 (11.3) 15 (12.3) Lacrimal drainage disorders 10 (10.5) 8 (6.0) 7 (5.7) Squint (strabismus) 7 (7.4) 6 (4.5) 6 (4.9) Developmental cataract 7 (7.4) 6 (4.5) 4 (3.3) Lid disorders 2 (2.1) 6 (4.5) 7 (5.7) Ocular trauma 5 (5.3) 5 (3.8) 4 (3.3) Ptosis 1 (1.1) 2 (1.5) 1 (0.8) Miscellaneous 1 (1.1) 2 (1.5) 1 (0.8) Total 95 (100) 133 (100) 122 (100) Percentages are column-wise, calculated within each age band. Morbidity by sex The rank order of morbidity was similar in boys and girls, with refractive error and vernal keratoconjunctivitis the two commonest disorders in each sex (Table 4). Of the 123 children with refractive error, 68 were boys and 55 were girls; of the 82 with vernal keratoconjunctivitis, 49 were boys and 33 were girls. Squint was the only category numerically more frequent in girls (11) than boys (8), while ptosis and miscellaneous disorders were recorded only in boys in this sample. Table 4. Ocular morbidity by sex. Ocular morbidity Male, n Female, n Refractive error 68 55 Vernal keratoconjunctivitis 49 33 Conjunctival disorders 27 20 Lacrimal drainage disorders 17 8 Squint (strabismus) 8 11 Developmental cataract 10 7 Lid disorders 9 6 Ocular trauma 6 8 Ptosis 4 0 Miscellaneous 4 0 Total 202 148 Counts derived by summing the age-stratified sex cross-tabulations; category totals equal the overall morbidity counts in Table 2.

In this hospital-based cross-sectional study of 350 children attending a tertiary care ophthalmology outpatient department in northern Karnataka, refractive error was the commonest ocular morbidity (35.1%), followed by vernal keratoconjunctivitis (23.4%); together these two conditions accounted for almost three-fifths of all presentations. Most affected children were of school-going age, and boys outnumbered girls across every age band. The predominance of refractive error confirmed our primary hypothesis and aligns this southern-Indian tertiary population with the wider national picture. The finding that refractive error leads the morbidity spectrum is highly consistent with both community and hospital-based Indian evidence. School surveys from Goa, Gujarat, and western Uttar Pradesh have all reported refractive error as the single most common ocular disorder in children.[4][5][6] In a screening study of primary schoolchildren in Goa, refractive error was likewise the leading morbidity, followed by conjunctival and other anterior-segment disease - a rank order that mirrors ours.[5] Hospital-based series reinforce the point: refraction-focused studies of children attending tertiary centres report uncorrected refractive error as the dominant reason for presentation, frequently accompanied by measurable visual impairment at first contact.[9] Our data extend this consistent pattern to a tertiary centre in northern Karnataka, a region under-represented in the published literature. The high proportion of vernal keratoconjunctivitis in our series is a notable regional feature. Vernal keratoconjunctivitis is a chronic, often seasonal, allergic disease of children in warm, dry climates, and its prominence here - nearly one in four children - likely reflects the hot, arid environment of the Ballari region.[11] This contrasts with cooler or differently distributed series in which allergic disease is less prominent, and it underscores the recognised influence of geography and climate on the paediatric ocular disease spectrum.[10] The recognition that vernal keratoconjunctivitis is common locally has practical implications, because inadequately treated disease can produce corneal complications and vision loss and now has evidence-based therapeutic options.[11] The distribution of the remaining disorders was also broadly concordant with earlier work, with the expected differences that arise from referral filtering. In a tertiary series from Kolkata and a paediatric outpatient study from Berhampur, Odisha, refractive error again led, followed by allergic and infective conjunctival disease, strabismus, and lid or lacrimal disorders - the same broad hierarchy we observed.[7][8] Where series differ, the differences are informative: some report congenital anomalies or cataract more prominently than we did, reflecting local referral patterns and the age structure of the attending population.[8] Consistent with the developmental biology of these conditions, we found developmental cataract, lacrimal drainage disorders, and conjunctival disease proportionally more frequent in the youngest (0-5-year) band, whereas vernal keratoconjunctivitis and refractive error were commoner in older, school-going children.[12][13] The age distribution - with most morbidity concentrated in the 5-10- and 10-15-year bands - is consistent with the emergence of symptomatic refractive error as children enter and progress through school, and with the age profile of vernal keratoconjunctivitis. This pattern has direct programmatic implications. Because uncorrected refractive error is easily detected and corrected, the concentration of disease in school-aged children strengthens the case for structured school vision screening, which has been shown to be feasible and cost-effective when class teachers are trained as first-level screeners.[9] Streamlined models for paediatric refraction and spectacle provision have been described for the Indian context and could be adapted locally to shorten the path from detection to correction.[10] Untreated, refractive error not only handicaps learning but is associated with asthenopia and headache and, in younger children, carries a risk of amblyopia.[3][14 ] The male predominance we observed (male-to-female ratio 1.36:1) is a recurring feature of hospital-based paediatric ophthalmology series in India and most plausibly reflects care-seeking behaviour and referral bias rather than a true excess of disease in boys.[7][8] This interpretation matters, because a sex differential in attendance - rather than in underlying morbidity - signals a potential inequity in access to eye care for girls that community-level screening and outreach could help to correct. As a descriptive, single-centre study we cannot quantify this gap, but the consistency of the pattern across Indian series makes it a reasonable target for further investigation. Taken together, these findings describe the paediatric ocular disease that presents to specialist care in this region and identify two largely treatable conditions - refractive error and vernal keratoconjunctivitis - as the dominant contributors. Because a tertiary outpatient sample reflects referral and care-seeking rather than population prevalence, our proportions should not be read as community prevalence estimates; rather, they indicate where clinical and training resources are most needed and where community interventions could reduce the flow of avoidable morbidity to hospital.[7] Strengths The main strengths of this study are its consecutive enrolment of every eligible child over a continuous 18-month period, which minimises selection bias within the attending population, and its standardised, ophthalmologist-led examination protocol including cycloplegic refraction and slit-lamp assessment. Reporting the full morbidity spectrum stratified by both age and sex provides a granular regional dataset from a part of southern India that is under-represented in the literature. Limitations Several limitations should temper interpretation. First, this is a single-centre, hospital-based study, so the observed proportions reflect referral and care-seeking patterns and cannot be extrapolated to community prevalence. Second, the analysis is descriptive and each child was assigned a single principal diagnosis, so coexisting morbidities may be under-counted and no formal tests of association or adjustment for confounding were undertaken. Third, visual acuity and refractive outcomes, although recorded clinically, were not quantitatively summarised, limiting our ability to describe the burden of visual impairment; the second study objective - the effect of disease on vision - is therefore only partially addressed. Fourth, an internal discrepancy of four patients between the aggregate and age-stratified sex counts in the source data requires reconciliation. Finally, the ethics reference number and a fully reconciled sample-size derivation should be resolved before submission. Clinical and public-health implications The concentration of treatable disease - chiefly refractive error and vernal keratoconjunctivitis - in school-aged children supports investment in school-based vision screening, teacher-led case detection, and accessible refraction and spectacle services in the Ballari region.[9][10] Awareness of the local prominence of vernal keratoconjunctivitis should inform clinician training and the availability of appropriate anti-allergic therapy. The apparent under-attendance of girls warrants targeted community outreach to ensure equitable access to paediatric eye care. Future research Future work should include community-based prevalence surveys in the same catchment to complement these hospital data, prospective quantification of visual acuity and visual-impairment outcomes with follow-up after refractive correction, and analytical studies of the determinants of the observed male predominance in attendance. Multicentre studies across climatic zones would help disentangle the geographic and seasonal drivers of vernal keratoconjunctivitis and other allergic eye disease in Indian children

In this tertiary care series from northern Karnataka, refractive error and vernal keratoconjunctivitis were the two commonest paediatric ocular morbidities, together accounting for the majority of presentations, and most affected children were of school-going age with a consistent male predominance. Because these leading conditions are largely preventable or treatable, the findings make a practical case for strengthening school vision screening, accessible refractive services, and community eye-health education in the region, and for equitable outreach to girls. DECLARATIONS Ethics approval and consent to participate The study was approved by the Institutional Ethics Committee of Ballari Medical College and Research Centre/VIMS, Ballari, and conducted in accordance with the Declaration of Helsinki. Informed consent was obtained from the parent or legal guardian of each participant. Consent for publication Not applicable Availability of data and materials The datasets generated and analysed during the current study are available from the corresponding author on reasonable request. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Conflicts of interest The authors declare no competing interests. Acknowledgements The authors thank the staff of the Department of Ophthalmology, VIMS/Ballari Medical College and Research Centre, for their support. [Supply names of any non-author contributors.].

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