Elsevier

Ophthalmology

Volume 113, Issue 1, January 2006, Pages 109-116
Ophthalmology

Original Article
Microbial Keratitis: Predisposing Factors and Morbidity

Presented at: Molecular Pathogenesis of Infectious and Inflammatory Eye Research Conference, August, 2004; Sydney, Australia, and 36th Royal Australian and New Zealand College of Ophthalmologists Annual General Meeting and Scientific Congress, November, 2004; Melbourne, Australia.
https://doi.org/10.1016/j.ophtha.2005.08.013Get rights and content

Purpose

To examine predisposing factors, treatment costs, and visual outcome of microbial keratitis in an ophthalmic casualty and inpatient population.

Design

Retrospective medical records review.

Participants

Fifteen- to 64-year-olds with microbial keratitis treated at the Royal Victorian Eye and Ear Hospital between May 2001 and April 2003 (n = 291).

Methods

Risk factors were identified from patient files. Demographic, clinical, and microbiological data; severity; outpatient visits; hospital bed days; and vision loss were examined.

Main Outcome Measures

Cost to treat (Australian dollars), vision loss, and factors influencing these outcomes.

Results

Ocular trauma (106/291 [36.4%]) and contact lens (CL) wear (98/291 [33.7%]) were the most commonly identified predisposing factors; 18 (6.1%) had multiple predisposing factors; 17 (5.8%), ocular surface disease; 20 (6.9%), herpetic eye disease; 4 (1.4%), systemic associations; 5 (1.7%), other; and 23 (7.9%), unknown cause. Of trauma cases, 90.6% involved males, compared with 44% to 57% for other groups (P<0.001). Contact lens wearers were younger than the other groups—mean age 30 years, compared with 40 to 47 years (P<0.01). Gram-negative organisms were isolated more frequently in CL wearers than trauma cases (18.7% vs. 6.5%, P = 0.01). The number of outpatient visits was 4±1 (median ± interquartile range), and 19.6% (57/291) were hospitalized for 5±2 days. Hospital resource use and vision loss were similar for predisposing factors but differed by causative microorganism. Eighty-eight percent of cases were scraped: acanthamoeba keratitis was the most expensive to treat, followed by fungal and herpetic keratitis and, lastly, culture-proven bacterial keratitis or culture-negative cases (P<0.0001). After treatment, 21.7% exhibited >2 lines of vision loss, and 1.6% of cases had ≥10 lines of vision loss. Vision loss was associated with clinical severity (P = 0.005).

Conclusions

Ocular trauma and CL wear are the major predisposing factors for microbial keratitis in this age range. These cases require significant hospital resources during treatment, and the keratitis may result in loss of vision.

Section snippets

Materials and Methods

All cases of microbial keratitis at the RVEEH in a 24-month period between May 2001 and April 2003 were identified through a retrospective medical records review. A total of 94 inpatient records and 822 emergency records with relevant diagnostic codes were identified and reviewed by 2 investigators (LK, KE). Inpatient files were reviewed with International Classification of Diseases 10 codes (H16.0 and H16.8), and emergency files were reviewed with relevant codes from the Victorian Emergency

Results

Contact lens wear (33.7%) and trauma (36.4%) were the most commonly identified causes of microbial keratitis in this review. There were 17 of 291 (6%) associated with ocular surface disease; 20 of 291 (7%), previous herpetic eye disease; and 4 of 291 (1%), systemic disease. A total of 18 cases were multifactorial (6.1%). There were no identifiable risk factors in 23 cases (7.9%). The cases in which diagnosis was uncertain were cases of less severe disease, and proportions of cases in which the

Discussion

Ocular trauma and CL wear have been identified here as the most common risk factors for microbial keratitis in this age range. The comparative morbidity of this condition in terms of visual loss and costs of treatment has been quantified for the first time.

This large case series comprises cases of presumed microbial keratitis based on clinical diagnosis. As with any clinical definition, there is the possibility that some noninfective cases have been included in our sample, making estimates of

References (19)

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Manuscript no. 2005-270.

This research was funded in part by the Australian Government via the Cooperative Research Centres Program, Canberra, Australia, and via a National Health and Medical Research Council (Canberra, Australia) Post-graduate Research Scholarship.

The authors have no conflicting relationships or commercial connection to the article’s topic.

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