To date, many studies on pediatric keratitis are single-center analyses, with emphasis on infectious causes, so there is still uncertainty about overall incidence rate and widely accepted presenting signs and symptoms for the disorder’s subtypes. Addressing this research gap, a 10-year report explores incidence and characteristics of keratitis for patients younger than 19 years of age residing in Olmsted County, Minnesota. The report was published in the British Journal of Ophthalmology.
From January 1, 2000 until December 31, 2009, 285 children were diagnosed with 294 cases of keratitis (21.4% presented with visual acuity of 20/40 or worse, 60.4% girls), according to the population-based investigation. The multi-clinic record review demonstrated an incidence rate of 78.0 per 100,000 individuals. Further, incidence rose throughout the study period (P <.001). Diagnoses were made, on average, at 15.3 years of age — more specifically, after contact lens wear at 16.5 years of age, and for infectious keratitis at 15.6 years of age.
Contact lens wear contributed to 45.6% of total diagnoses and 44% of bilateral cases. This category represented infections and inflammation brought on by other factors. Investigators suggest that in previous studies and the present analysis, impacts include storage in tap water, poor cleaning, prolonged wear, and sleeping or swimming in lenses. Also cited were patients not visiting their practitioner once each year, and an increase in popularity of cosmetic lenses.
Microbial etiology was demonstrated in 24.5% of the total. Of these children, 10.0% had an underlying ocular comorbidity such as trauma or disorder of the adnexa, and 6.9% displayed a systemic comorbidity, for example Stevens-Johnson syndrome. Previous investigations show trauma as the typical cause for pediatric keratitis in developing countries, although contact lenses are a greater influence in economically-developed regions.
The third out of 4 main categories, unspecified keratitis, comprised keratitis secondary to blepharitis, keratoconjunctivitis, and allergic keratitis — experienced by 22.1% of the sample. More female patients, 63% occupied this set. Here, underlying conditions also played a meaningful role, with 7 of 65 exhibiting a medical comorbidity such as asthma or eczema who may be prone to allergic keratitis.
Fourth most common was keratitis sicca — 7.8% of the sample — with an incidence rate of 6.3 per 100,000, a proportion comparable to prior research, but diverges from a study in India that found 2688 per 1 million. In the current analysis, there were not enough cases of keratitis sicca to calculate incidence rate across time. “Children with infectious keratitis tended to have the worst presenting vision and the best final vision, whereas those with keratitis sicca had the best presenting vision and the worst final vision,” the study explains.
Medical chart data for the retrospective study was gathered by ICD-9 codes from Rochester Epidemiology Project (REP), a county-wide system of linked records — this may represent a limitation of variable documentation by different clinics. Other factors were that some residents could have sought care outside of Olmsted County, and the overall sample was not diverse. Finally, contact lens wear was not broken down into sub-categories of infectious or non-infectious origin, thus microbial etiology may have been underestimated.
Tanke LB, Kim EJ, Butterfield SD, et al. Incidence and clinical characteristics of paediatric keratitis. Br J Ophthalmol. Published online first on May 13, 2022. doi:10.1136/bjophthalmol-2021-320793