Corneal ulceration remains one of the most common and potentially sight-threatening ocular emergencies encountered in clinical ophthalmology. It accounts for a significant proportion of visual impairment in developing countries, particularly in Asia and Africa, where access to specialized eye care is limited and risk factors are more prevalent (1). Corneal ulcers, most commonly caused by infectious agents, result from a breach in the corneal epithelium allowing microbial invasion. The etiology may be bacterial, fungal, viral, or parasitic, with bacteria and fungi being the leading culprits in tropical and subtropical regions like India (2). The clinical presentation varies depending on the causative agent; bacterial ulcers typically present with rapid progression, pain, and purulent discharge, whereas fungal ulcers often exhibit a slower course, with dry-appearing lesions, feathery borders, and satellite lesions (3).

In countries like India, the incidence of corneal ulcer is considerably high due to a combination of factors including agricultural injuries, poor ocular hygiene, misuse of topical steroids, and delayed treatment-seeking behavior. Trauma with vegetative matter is a major predisposing factor for fungal keratitis, while bacterial ulcers are frequently associated with contact lens wear or ocular surface disease. The microbial spectrum of corneal ulcers has been shown to vary significantly by region and season. Studies from South India have identified Fusarium species, Aspergillus, and Streptococcus pneumoniae as major pathogens (4, 5). However, the pattern of microbial isolates is dynamic, influenced by changes in environmental factors, antimicrobial usage, and regional practices, necessitating continuous surveillance.

Though several hospital-based studies have documented the microbiological patterns of corneal ulcers, many focus solely on laboratory data without correlating with clinical findings. Moreover, most existing literature tends to report older data, and limited research has been done in recent years that offer a comprehensive view combining clinical characteristics, risk factors, microbiological spectrum, and outcomes in one cohort. There is also a need to evaluate antibiotic sensitivity patterns regularly to inform empirical therapy, especially in the context of rising antimicrobial resistance. Despite the prevalence of corneal ulcers and the availability of some regional data, there remains a lack of up-to-date, integrated clinical and microbiological profiling from tertiary care hospitals in many parts of South India. Additionally, the changing trends in microbial prevalence and antibiotic resistance patterns underscore the need for periodic reassessment. This study was undertaken to address this gap by evaluating the clinical features, associated risk factors, microbial etiology, and in-hospital outcomes of patients with corneal ulcers. The aim is to provide updated and comprehensive data that can assist in early diagnosis, effective treatment planning, and prevention of vision loss.

This hospital-based prospective observational study was conducted in the Department of Ophthalmology at Mamata Medical College and General Hospital, Khammam, Telangana. The study spanned a period of 18 months and included a total of 75 patients who presented with clinical features suggestive of infectious corneal ulcers.

Inclusion Criteria:

• Patients of all age groups and both sexes presenting with corneal ulcers of presumed infectious origin.
• Ulcers characterized by loss of corneal epithelium with stromal infiltration, with or without hypopyon.
• Willingness to participate in the study with informed consent.

Exclusion Criteria:

• Patients with sterile corneal ulcers (e.g., neurotrophic, exposure, or autoimmune ulcers).
• Ulcers secondary to viral causes (herpetic keratitis) confirmed clinically.
• Patients with a history of recent ocular surgery or trauma requiring primary repair.
• Patients unwilling to provide consent.

Clinical Evaluation: A detailed history was recorded including demographic details, predisposing factors (such as trauma, contact lens use, prior steroid use), duration of symptoms, and any previous treatment. Visual acuity assessment, slit-lamp biomicroscopy, and fluorescein staining were done for all cases. Characteristics of the ulcer (size, shape, depth, margins, presence of hypopyon, and corneal thinning) were documented.

Sample Collection and Microbiological Workup: Corneal scrapings were obtained under aseptic conditions after instillation of topical anesthetic (0.5% proparacaine hydrochloride). Samples were collected using a sterile platinum spatula or Bard-Parker blade No. 15 and were subjected to both direct microscopy and culture.

• Microscopy: Smears were prepared for Gram staining, KOH (10%) wet mount, and Giemsa staining to identify bacterial and fungal elements.
• Culture: The remaining specimen was inoculated onto blood agar, chocolate agar, Sabouraud dextrose agar (SDA), and brain heart infusion broth. The culture media were incubated and observed for growth up to 7 days for bacteria and 14 days for fungi.
• Microbial isolates were identified using standard microbiological techniques based on colony morphology, staining, and biochemical tests. Antimicrobial susceptibility testing for bacterial isolates was performed using the Kirby-Bauer disc diffusion method in accordance with CLSI guidelines.

Treatment and Follow-up: Based on preliminary smear results, empirical treatment was initiated typically using broad-spectrum topical antibiotics and antifungals as per clinical suspicion. Therapy was modified after culture and sensitivity reports. Patients were followed up at regular intervals to monitor healing, complications, and final visual outcomes.

Data Analysis: All collected data were entered into Microsoft Excel and analyzed using appropriate statistical tools. Frequencies, percentages, and means were calculated for descriptive data. Association between clinical features and microbiological findings was evaluated using Chi-square test, with a significance level set at p < 0.05.

Ethical Considerations: The study was approved by the Institutional Ethics Committee of Mamata Medical College, Khammam. Written informed consent was obtained from all participants (or their guardians in case of minors) prior to enrollment.

Table 1: Demographic Profile of Patients with Corneal Ulcers (n = 75)

In this study of 75 patients with corneal ulcers, the mean age was 43.2 ± 17.6 years, with the majority (68%) falling between 21 and 60 years, indicating that the disease predominantly affects the working-age population. A male predominance was noted (61.3%), likely reflecting greater exposure to outdoor occupations and associated ocular risks. The ulcers were nearly equally distributed between the right eye (52%) and left eye (48%), suggesting no laterality bias (Table 1).

Table 2: Predisposing Factors Associated with Corneal Ulcers (n = 75)

In this study, ocular trauma emerged as the most common predisposing factor, reported in 56% of patients. Among these, a significant proportion had a history of injury with vegetative matter, a typical risk in agricultural settings. Topical steroid use prior to presentation was noted in 14.7% of cases, which may have contributed to worsening or masking of the infection, particularly in fungal keratitis. Other contributing factors included contact lens use (8%), chronic ocular surface disease (9.3%), systemic illnesses such as diabetes (12%), and previous ocular surgeries (6.7%). Notably, 10.7% of patients had no identifiable risk factor, which may point toward subclinical systemic or local immune dysfunction or unrecognized trauma (Table 2).

Table 3: Duration of Symptoms and Previous Treatment in Patients with Corneal Ulcers (n = 75)

The duration of symptoms before presentation varied among patients, with the majority (45.3%) presenting between 3 and 7 days, followed by 28% presenting within 3 days, and 26.7% after more than a week, with a mean duration of 5.2 ± 2.4 days. This suggests that while some patients sought early care, a considerable proportion delayed consultation, potentially leading to more severe disease at presentation. Regarding treatment history, 68% of patients had received some form of treatment prior to visiting the hospital, often from local practitioners or self-medication, whereas 32% had not received any prior therapy (Table 3).

Table 4: Visual Acuity and Slit-Lamp Findings at Presentation (n = 75)

At presentation, visual acuity was severely impaired in the majority of patients, with 45.3% showing vision worse than 3/60 but with perception of light, and only 8% retaining vision of 6/18 or better. This reflects late presentation and possibly advanced ulceration. Slit-lamp examination revealed that central ulcers were most common (58.7%), followed by paracentral (22.7%) and peripheral (18.7%) involvement. The majority of ulcers (60%) measured 2–5 mm, while 28% were larger than 5 mm, suggesting moderate-to-severe disease in a significant number of cases. In terms of depth, 46.7% had mid-stromal involvement, and 32% showed deep stromal extension, which are important predictors of poor healing and visual outcomes. Hypopyon was noted in 44% of cases, and corneal thinning or perforation was observed in 32%, emphasizing the severity of disease and the risk of complications at initial presentation (Table 4).

Table 5: Microscopy Findings from Corneal Scrapings (n = 75)

Microscopy of corneal scrapings provided useful preliminary diagnostic information in many cases. Gram staining revealed Gram-positive cocci in 25.3% and Gram-negative bacilli in 9.3%, while 65.3% of smears showed no organisms, possibly due to prior antibiotic use or low microbial load. KOH wet mount, particularly useful for fungal identification, showed septate hyphae in 28% and aseptate hyphae in 5.3% of cases, supporting a clinical suspicion of fungal keratitis in nearly one-third of patients. Giemsa staining demonstrated inflammatory cells in 64%, indicating active infection or immune response, while bacteria or fungi were directly visualized in 22.7% (Table 5).

Table 6: Distribution of Microbial Isolates in Positive Cultures (n = 47)

Table 6 shows that, among the 47 culture-positive cases, bacterial isolates accounted for 26 cases (55.3%) and fungal isolates for 21 cases (44.7%). The most commonly isolated bacterium was Streptococcus pneumoniae (13.3%), followed by Staphylococcus aureus (10.7%), both of which are frequently implicated in corneal infections in India. Pseudomonas aeruginosa (6.7%), often associated with contact lens use and aggressive keratitis, and Klebsiella pneumoniae (4.0%), a less common but significant pathogen, were also identified. Among fungal isolates, Fusarium species (12.0%) were the most prevalent, followed by Aspergillus species (9.3%), which is consistent with trauma-related fungal ulcers common in tropical climates. Other isolates included Candida species (4.0%) and dematiaceous fungi (2.7%).

Table 7: Comparison of Mean Duration of Symptoms between Culture-Positive and Culture-Negative Cases

Table 7 compares the mean duration of symptoms before presentation between patients with culture-positive and culture-negative corneal ulcers. The mean duration was 5.34 ± 1.83 days in the culture-positive group and 4.65 ± 1.83 days in the culture-negative group. Although the culture-positive group had a slightly longer delay in presentation, the difference was not statistically significant (p = 0.119).

Table 8: Treatment Modalities Used in Corneal Ulcer Patients (n = 75)

In this study, empirical therapy was initiated in all patients at the time of presentation based on clinical features and smear findings. Topical broad-spectrum antibiotics such as moxifloxacin or ofloxacin were the most commonly used initial agents, prescribed in 54.7% of patients. Antifungal eye drops like natamycin 5% or voriconazole were administered in 30.7%, especially when fungal infection was suspected. A combination of both antibiotic and antifungal therapy was used in 14.7% of patients, reflecting mixed clinical presentations or uncertain etiologies. Cycloplegics and lubricants were widely used (86.7%) to relieve pain and support corneal healing. Additionally, oral medications, including fluconazole or ciprofloxacin, were used in 24% of cases, mostly in moderate to severe infections or when there was deep stromal involvement (Table 8).

Table 9: Clinical Outcome at Final Follow-Up (n = 75)

At final follow-up, 76% of patients achieved complete ulcer healing with scar formation, while 14.7% showed partial healing with residual corneal thinning, and 9.3% experienced no significant improvement or worsening of the condition. Among complications, corneal thinning was observed in 24%, and perforation requiring surgical intervention occurred in 6.7%, indicating that a subset of patients presented with or developed severe disease. Additionally, secondary glaucoma or uveitis was noted in 4%, further complicating recovery. In terms of visual outcomes, only 28% of eyes regained a best-corrected visual acuity (BCVA) of ≥6/18, whereas the majority (41.3%) had BCVA <6/60 but retained perception of light. Alarmingly, 8% had no perception of light (NPL) at final follow-up, representing irreversible vision loss (Table 9).

This figure 2 shows the odds ratios for clinical factors associated with poor visual outcomes in corneal ulcer patients. Although none of the predictors reached statistical significance, deep stromal involvement, delayed presentation (>7 days), and fungal etiology showed a trend toward increased risk of poor vision (final acuity <6/60). The wide confidence intervals suggest limited power, but the observed patterns highlight the clinical importance of early presentation and prompt management, particularly in deep or fungal ulcers.

Infective corneal ulcers remain a leading cause of corneal blindness, particularly in developing countries such as India, where the burden is heightened by factors like agricultural trauma, lack of awareness, and inadequate early treatment. This study conducted at Mamata Medical College, Khammam, provides a comprehensive overview of the clinical presentation, predisposing factors, microbial profile, treatment, and outcomes of corneal ulcer patients in a tertiary care setting over an 18-month period.

The majority of patients in this study were males (61.3%) with a mean age of 43.2 ± 17.6 years. A similar male preponderance has been noted in earlier studies by Bharathi et al. (6) and Armstrong (7), attributed to greater outdoor exposure and occupational risks. Most patients were from rural areas (65.3%) and involved in agriculture or manual labor, reinforcing findings by Srinivasan et al. (1997), who also noted a high prevalence of ulcers in agrarian populations.

Trauma was the most significant predisposing factor in this study (56%), especially with vegetative matter (36%). This is consistent with other Indian studies, where trauma accounts for 40–65% of infectious keratitis cases (8). Misuse of topical corticosteroids was noted in 14.7% of cases, a risk factor known to exacerbate fungal

infections and delay healing. Contact lens use was comparatively lower (8%), reflecting its lesser prevalence in rural India, though it remains a major cause in urban and developed settings (9).

Most ulcers were central (58.7%) and measured 2–5 mm (60%) in size. Hypopyon was seen in 44% and corneal thinning in 24%, suggesting moderate-to-severe disease at presentation. Visual acuity at presentation was <6/60 in 77.3% of patients, indicating delayed treatment-seeking, a trend seen in several Indian studies (10).

Culture positivity was achieved in 62.7% of cases, comparable to rates reported by Gopinathan et al. (2009) and Bharathi et al. (2003). Among the bacterial isolates, Streptococcus pneumoniae (13.3%) and Staphylococcus aureus (10.7%) were predominant, in agreement with findings by Srinivasan et al. (1997). Pseudomonas aeruginosa was isolated in 6.7%, typically associated with contact lens use and poor hygiene. Fungal pathogens were isolated in 28% of patients, with Fusarium species being the most common (12%), followed by Aspergillus (9.3%), similar to the microbiological patterns observed by Thomas et al. (2005) and Lalitha et al. (11).

Empirical therapy was initiated in all patients based on smear results, and modified in 70.2% of culture-positive cases after sensitivity testing. Complete healing with scar formation was achieved in 76% of patients. However, despite ulcer resolution, only 28% of eyes achieved a final visual acuity of ≥6/18, and 8% resulted in no perception of light. The poor visual outcome in many patients may be attributed to the central location of ulcers, large size, delayed presentation, and complications like perforation. These trends are similar to those reported in studies by Basak et al. (2005) and Lalitha et al. (2007), which emphasize that early intervention is critical for vision preservation.

Comparison with Previous Studies:

This study reaffirms that corneal ulcers are a major ocular morbidity in rural India, with trauma especially from vegetative matter being the leading predisposing factor. Gram-positive cocci and filamentous fungi remain the predominant causative agents. Early identification through smear and culture, followed by targeted antimicrobial therapy, plays a critical role in ulcer healing. However, despite successful microbiological cure, visual prognosis remains guarded, particularly in cases with delayed presentation or central corneal involvement. Continuous surveillance of microbial trends and patient education on early eye care are essential to reduce the burden of corneal blindness in resource-limited settings.

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