Successful Empirical Treatment of a Severe Corneal Abscess After Delayed Consultation in a Low‐Resource Setting: A Case Report

ABSTRACT

Corneal abscesses remain an important cause of preventable monocular blindness, particularly where access to specialized eye care is limited. We report a 34‐year‐old man from the Democratic Republic of the Congo who presented with a severe corneal abscess after three weeks of symptoms and prior self‐medication with unidentified topical eye drops. In the absence of microbiological investigations, intensive empirical medical treatment achieved infection control and partial visual recovery. This case highlights the importance of timely referral and clinically guided management when diagnostic resources are limited.

Key Clinical Message

Severe corneal abscesses related to delayed consultation and self‐medication remain a major cause of avoidable visual impairment in low‐resource settings. This case demonstrates that intensive empirical medical treatment can result in favorable anatomical and functional outcomes even in the absence of microbiological investigations.

1. Introduction

Infectious keratitis and corneal abscesses remain a major cause of visual impairment and blindness worldwide, particularly in low‐resource settings [1]. Corneal opacity, a frequent sequela of infectious keratitis, is currently ranked as the fourth leading cause of blindness globally, accounting for approximately 5% of global blindness and affecting an estimated 4 to 6 million people with unilateral or bilateral visual impairment. These conditions therefore represent a substantial and largely preventable public health burden worldwide [1, 2, 3].

The incidence of microbial keratitis shows marked geographic variation, ranging from 2.5 to over 700 cases per 100,000 person‐years, with significantly higher rates reported in low‐ and middle‐income countries [3, 4]. This disparity is strongly influenced by climatic conditions, occupational exposure, socioeconomic status, and access to eye care services [1]. In tropical regions, fungal keratitis may account for 40%–60% of cases, whereas bacterial keratitis predominates in temperate climates, reflecting environmental and behavioral differences [5].

Delayed consultation is a well‐established predictor of disease severity and poor visual outcome in infectious keratitis [4, 6]. Several studies conducted in Africa and Asia have reported that 30%–60% of patients present more than two weeks after symptom onset, frequently with advanced corneal ulcers, hypopyon, or impending perforation [7]. Late presentation has been consistently associated with increased rates of corneal scarring, need for surgical intervention, and permanent vision loss [6].

Self‐medication represents another major contributor to delayed presentation and disease progression [8]. The use of non‐prescribed topical medications, including antibiotics, corticosteroids, and traditional eye remedies, is common in low‐resource settings and may temporarily mask symptoms while allowing infection to progress [9, 10]. Previous studies have demonstrated that self‐medication is associated with larger ulcer size at presentation, increased complication rates, and poorer visual prognosis [11].

Management of severe corneal abscesses in low‐resource settings is further complicated by the limited availability of microbiological diagnostic facilities, including corneal scraping, culture, and antimicrobial susceptibility testing [3]. As a result, treatment is frequently empirical and based on clinical judgment rather than laboratory confirmation [4, 9]. Despite these constraints, evidence suggests that early initiation of intensive broad‐spectrum empirical therapy, combined with close clinical monitoring, can lead to infection control and acceptable visual outcomes in a significant proportion of patients [12].

Case reports from resource‐limited settings play an important role in highlighting real‐world challenges and feasible management strategies. They provide valuable insight into the interaction between delayed consultation, self‐medication, and limited diagnostic capacity, while also demonstrating that favorable outcomes remain achievable under constrained conditions [4, 9].

Although delayed consultation, self‐medication, and limited access to microbiological diagnosis have been individually reported in infectious keratitis, their combination poses a particular therapeutic challenge in resource‐limited settings. Unlike many reported cases in which microbiological identification allows targeted antimicrobial therapy, the present case involved a severe corneal abscess with hypopyon after three weeks of symptoms and prior use of unidentified topical medications, while corneal scraping and culture were unavailable. Management therefore relied entirely on clinical assessment and intensive empirical therapy, which achieved infection control and partial visual recovery. This case highlights the practical challenges and potential effectiveness of clinically guided empirical management of advanced infectious keratitis when microbiological diagnosis is unavailable.

2. Case Presentation/Examination

A 34‐year‐old man with no previous ophthalmologic history presented with a three‐week history of severe pain, redness, purulent discharge, and progressive visual loss in the left eye. Prior to consultation, he reported self‐medication with several topical eye drops of unknown composition, obtained without prescription. There was no history of ocular trauma or contact lens use. On examination, visual acuity in the left eye was reduced to counting fingers at 1 m (CF at 1 m), assessed at the bedside because of the severity of visual impairment. Visual acuity in the right eye was 10/10 (1.0 decimal), measured using a standard Snellen chart at 5 m. External examination revealed mild eyelid edema. Slit‐lamp examination of the left eye showed diffuse conjunctival hyperemia with purulent discharge and chemosis, together with a large, dense paracentral temporal stromal infiltrate measuring approximately 5 × 4 mm extending toward the visual axis, with an overlying epithelial defect confirmed by fluorescein staining (Figure 1), surrounding stromal edema, and a small hypopyon. The pupil was reactive, and the lens was clear. Fundus examination of the affected eye could not be performed at presentation owing to corneal opacity from the dense infiltrate. Examination of the right eye was unremarkable.

FIGURE 1.

Clinical appearance of the severe left corneal abscess at presentation. (A) Marked conjunctival hyperemia with a dense paracentral temporal corneal stromal infiltrate. (B) Corneal infiltrate measuring approximately 5 × 4 mm, extending toward the visual axis, with an associated inferior hypopyon (black arrow). (C) Additional view showing the extent and paracentral temporal location of the corneal infiltrate.

3. Differential Diagnosis, Investigations and Treatment

Given the absence of microbiological confirmation, several differential diagnoses were considered on clinical grounds. Bacterial keratitis was considered the leading hypothesis because of the purulent discharge, dense stromal infiltrate, epithelial defect, and associated hypopyon. Fungal keratitis was also considered because of the subacute three‐week course and the tropical setting, and could not be excluded clinically. Acanthamoeba keratitis was considered less likely in the absence of contact lens use. Herpetic keratitis was also considered less likely because the clinical presentation was not considered typical of herpetic disease. However, none of these etiologies could be definitively confirmed or excluded without microbiological investigation. Therefore, severe infectious keratitis with corneal abscess formation was retained as a clinical syndromic diagnosis rather than an etiologically confirmed diagnosis. Microbiological investigations, including corneal scraping, culture, and antimicrobial susceptibility testing, could not be performed because these facilities were unavailable at the treating center.

Given the severity of the presentation and the inability to establish a microbiological diagnosis, intensive empirical therapy was initiated with fortified topical cefotaxime, topical natamycin, and topical ganciclovir, together with atropine 1% for cycloplegia and ocular lubricants. Cefotaxime was used for antibacterial coverage, while natamycin was included because a fungal etiology could not be excluded in this tropical setting. Ganciclovir was included as part of the initial empirical regimen because the causative etiology could not be established, although no specific clinical features of herpetic keratitis were documented. Topical medications were administered hourly during the first week and subsequently tapered according to the clinical response, with close clinical monitoring throughout treatment.

4. Conclusion and Results

After one month of follow‐up, the infection was successfully controlled, with complete resolution of the corneal infiltrate and hypopyon. Visual acuity in the left eye improved to a Snellen‐equivalent of 2/10 (approximately 0.2 decimal), measured at 5 m with pinhole correction. The final examination revealed a paracentral temporal corneal scar (Figure 2). As corneal clarity improved during follow‐up, fundus examination of the affected eye became possible and showed no evidence of vitritis or retinal or choroidal abnormalities. Ocular B‐scan ultrasonography was not performed. The patient reported marked pain relief and expressed satisfaction with the outcome, and optical correction was proposed to optimize visual function.

FIGURE 2.

Clinical appearance of the left eye one month after intensive empirical treatment. (A) Resolution of the active corneal infection with residual paracentral temporal corneal scarring. (B) Additional view showing the residual corneal scar after treatment.

This favorable anatomical and functional outcome, achieved despite delayed presentation and the absence of microbiological confirmation, illustrates the potential role of carefully monitored empirical therapy when microbiological diagnosis is unavailable.

5. Discussion

Self‐medication is an important contributor to delayed presentation and disease severity in microbial keratitis, particularly in low‐resource settings. Studies from sub‐Saharan Africa and South Asia have reported frequent use of non‐prescribed topical medications before specialist consultation, including antibiotics, corticosteroids, and traditional eye remedies [8]. Inappropriate topical treatment may temporarily mask symptoms and delay appropriate care, and corticosteroid use may worsen fungal keratitis through local immunosuppression [4, 9]. In our patient, the use of unidentified topical eye drops likely contributed to delayed referral and disease progression.

Our patient's three‐week delay before presentation is consistent with patterns already well documented in this setting, where financial constraints, limited health coverage, shortages of eye care professionals, and geographic barriers restrict timely access to specialized ophthalmologic care [7, 13]. In eastern Democratic Republic of the Congo, insecurity and transportation difficulties further compound these structural barriers.

Management was additionally complicated by the unavailability of microbiological investigations, requiring a diagnostic and therapeutic approach based primarily on clinical assessment. Bacterial keratitis was considered the leading diagnosis because of the purulent discharge, dense stromal infiltrate, epithelial defect, and hypopyon. Fungal keratitis could not be excluded given the subacute course and tropical setting, whereas Acanthamoeba keratitis was considered less likely in the absence of contact lens use. Herpetic keratitis was also considered less likely because the overall clinical presentation was not typical of herpetic disease. Given that fungal pathogens account for a substantial proportion of microbial keratitis in tropical regions [4, 5], and considering evidence from the Mycotic Ulcer Treatment Trial supporting the use of 5% natamycin for filamentous fungal keratitis [14], empirical antibacterial and antifungal coverage was initiated. Ganciclovir was also included in the initial empirical regimen because the causative etiology could not be definitively established, although no specific clinical features of herpetic keratitis were documented.

Despite the absence of microbiological confirmation, infection control was achieved with partial visual recovery. Visual outcome in microbial keratitis is influenced by ulcer size, depth, and proximity to the visual axis [11, 12], and central corneal involvement is associated with poorer functional outcomes than paracentral or peripheral disease [12, 15]. In our patient, the paracentral location of the residual scar likely contributed to the preservation of functional vision.

Previous studies of microbial keratitis have emphasized the importance of microbiological identification for guiding antimicrobial therapy and have shown that delayed presentation is associated with poorer outcomes [3, 4, 7]. The present case is distinctive because several challenges occurred simultaneously: a three‐week delay before consultation, prior unsupervised use of unidentified topical medications, a severe corneal abscess with hypopyon, and the unavailability of corneal scraping and culture. Consequently, management relied entirely on clinical assessment and empirical antimicrobial therapy. Despite these constraints, infection control and partial visual recovery were achieved. This case therefore illustrates the potential role of carefully monitored, clinically guided empirical treatment when microbiological diagnosis is unavailable, while emphasizing that microbiological investigation should remain the preferred approach whenever feasible. Improved public awareness, timely referral, appropriate regulation of ophthalmic drug dispensing, and greater access to microbiological diagnosis may help reduce preventable visual impairment from infectious keratitis in resource‐limited settings.

Author Contributions

Gloria Nshokano Simba: conceptualization, writing – original draft, writing – review and editing. Fidele Kabego Kulimushi: validation, writing – original draft, writing – review and editing. Christian Mwetaminwa Iyimba: validation, writing – original draft, writing – review and editing. Roméo Bujiriri Murhega: conceptualization, supervision, writing – original draft, writing – review and editing.

Funding

The authors have nothing to report.

Ethics Statement

Ethics approval was not required for this case report in accordance with local guidelines.

Consent

Written informed consent was obtained from the patient for publication of this case report.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data supporting the findings of this case report are available from the corresponding author upon reasonable request. The data are not publicly available due to privacy and ethical restrictions.