Corneal ulceration, a severe manifestation of infectious keratitis, remains one of the leading causes of preventable corneal blindness worldwide. The burden is disproportionately higher in developing countries, particularly within tropical and subtropical regions where climatic and occupational factors predispose populations to ocular trauma and subsequent infection. In India, corneal blindness constitutes a major public health concern, contributing significantly to visual disability among working-age individuals. The epidemiological pattern of microbial keratitis demonstrates considerable geographic variability. [1,2]

In temperate and industrialized nations, bacterial keratitis predominates and is frequently associated with contact lens wear, ocular surface disease, and postoperative complications. Conversely, in agrarian and tropical regions such as North India, fungal keratitis represents a substantial proportion of cases, often linked to vegetative trauma, agricultural exposure, and delayed healthcare access.[3]

Over the past decade, several studies across India have reported evolving trends in the microbiological spectrum of corneal ulcers. While fungal pathogens such as Aspergillus and Fusarium species continue to dominate in rural populations, there is emerging evidence of increasing bacterial resistance to commonly used antibiotics. The growing prevalence of multidrug-resistant Gram-negative organisms poses
a significant therapeutic challenge, often resulting in prolonged disease course, increased healthcare costs, and poorer visual outcomes.[4,5]

Socioeconomic determinants, literacy levels, environmental exposure, and seasonal variations further influence disease distribution. Monsoon humidity, post-harvest agricultural activity, and dust exposure are well-recognized contributors to increased fungal keratitis incidence in North India. In contrast, urbanization and increased contact lens usage are gradually shifting certain demographic subsets toward
bacterial predominance.

Early and accurate microbiological diagnosis remains the cornerstone of effective management. Direct microscopy, culture techniques, and antimicrobial susceptibility testing guide targeted therapy and help mitigate complications such as corneal perforation and irreversible visual loss. However, empirical treatment is still widely practiced, particularly in peripheral healthcare settings, which maycontribute to inappropriate antibiotic use and resistance development.[6,7]

Given these dynamic trends, continuous regional surveillance is essential to understand changing pathogen profiles and resistance patterns. Such data are critical for developing evidence-based empirical treatment guidelines tailored to local epidemiology. The present hypothetical retrospective study was therefore designed to evaluate the shifting patterns of bacterial and fungal corneal ulcers in North India and to compare findings with national and international observations.

This is a Prospective observational study conducted in Department of Ophthalmology, tertiary care teaching hospital for a period of 18 months. The samples from the patients presenting to the ophthalmology outpatient department with clinical diagnosis of ocular infection were collected and sent to Microbiology department. Patients showing Clinical evidence of infectious ocular disease were included in the study where patients with non-infectious inflammatory ocular conditions, Allergic conjunctivitis and incomplete clinical records were excluded from the study. For each patient, there Age, sex, residence, occupation, History of trauma, contact lens use, prior steroid use, Systemic comorbidities (e.g., diabetes), Slit lamp examination findings were recorded and documented. Microbiological Evaluation Conjunctival swab, Corneal scraping and Lacrimal sac discharge were collected where indicated: Laboratory procedures included: • Gram staining • 10% KOH mount • Bacterial culture on blood agar and MacConkey agar • Fungal culture on Sabouraud dextrose agar Statistical Analysis Data were analyzed using descriptive statistics. Results were expressed as mean ± standard deviation for continuous variables and percentages for categorical variables.

Prevalence

Ocular infections accounted for 20.4% of total ophthalmology outpatient visits during the study period. A total of 648 patients were included, reflecting a significant infectious burden.

Demographic Distribution

The highest prevalence was observed in the 21–40 years age group (35.8%), followed by 41–60 years (28.7%), 0–20 years (20.4%), and >60 years (15.1%). The mean age was 37.9 ± 16.8 years. Males constituted 59.6% (n=386) and females 40.4% (n=262). Rural residents accounted for 64.3% of cases.

Clinical Spectrum

Conjunctivitis was the most common diagnosis (40.2%), followed by microbial keratitis (32.1%), blepharitis (10.8%), dacryocystitis (8.3%), hordeolum (5.7%), endophthalmitis (2.3%), and others (0.6%). A relative increase in microbial keratitis was observed compared to earlier regional trends.[table 1]

Microbiological Findings

Out of 648 samples processed, culture positivity was 71.8%. Bacterial isolates constituted 53.6% of positive cultures, while fungal isolates accounted for 42.7%. Among bacteria, Staphylococcus aureus (29.4%) was most common, followed by Streptococcus pneumoniae (15.7%), Pseudomonas aeruginosa (6.8%), and other Gram-negative bacilli (1.7%). Among fungi, Aspergillus species (25.1%) predominated, followed by Fusarium species (13.8%) and Candida species (3.8%).

Table 2

Risk Factors

Ocular trauma was present in 33.5% of cases and showed strong association with fungal keratitis, particularly vegetative trauma. Agricultural exposure was noted in 28.6%, contact lens use in 15.2%, prior topical steroid use in 17.9%, and diabetes mellitus in 11.4%.

The present study confirms that ocular infections account for approximately one-fifth of ophthalmology outpatient visits, consistent with recent Indian epidemiological data [1,2]. Young adult males from rural backgrounds were predominantly affected, reflecting occupational exposure and agricultural practices common in North India.

Conjunctivitis remained the most common presentation; however, microbial keratitis constituted nearly one-third of cases, indicating an increasing burden of potentially vision-threatening infections. Similar rising trends of keratitis have been documented in North Indian tertiary centres [3].

The culture positivity rate (71.8%) was comparable to previous Indian reports (65–75%) [3,6]. Bacterial pathogens predominated overall, with Staphylococcus aureus as the most common isolate, consistent with earlier Indian studies [3,6].

A notable finding was the high proportion of fungal isolates (42.7%), aligning with tropical Indian data reporting fungal keratitis rates between 35–50% [2,5]. The predominance of Aspergillus and Fusarium species reflects climatic and environmental influences.

Ocular trauma, particularly with vegetative matter, was the most significant risk factor. Similar associations have been reported across Indian studies [2,3]. Prior topical steroid use emerged as a major modifiable risk factor, supporting concerns raised in recent literature regarding irrational steroid usage in red-eye conditions [1,4].

Compared to Western countries where bacterial keratitis and contact lens use predominate, the higher fungal prevalence in India highlights the importance of region-specific treatment protocols.

Strengthening early microbiological diagnosis, regulating steroid dispensing, and enhancing public awareness regarding eye protection are essential to reduce the burden of vision-threatening infections.

This highlights the dynamic nature of microbial keratitis in North India. Fungal keratitis remains predominant, while bacterial isolates demonstrate increasing resistance patterns. Region-specific treatment strategies, early laboratory confirmation, and preventive measures in high-risk populations are crucial to reduce ocular morbidity.

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