Patients with both microbial and herpes simplex keratitis (HSK) may be more prone to significant ocular morbidity and poor visual outcomes, new research reports. The team of investigators from Australia also found that previous HSK and corneal and ocular surface diseases were risk factors and that gram-positive bacteria were the most commonly associated organisms.

The retrospective case review evaluated 121 patients with clinically presumed concomitant microbial keratitis and HSK who were about 70 years old. The study defined “poor” outcomes as final VA worse than 6/60, a decrease in VA during treatment, complications or necessary surgical intervention.

Out of 126 cases, the predisposing factors included 20 incidents of blepharitis (16%) and 19 corneal transplants (15%). Forty-six individuals (37%) had prior HSK. Out of 116 isolates, the most commonly found were coagulase-negative staphylococci (51, 44%), Staphylococcus aureus (11, 9%) and Pseudomonas aeruginosa (11, 9%).

Patients’ VA at the initial visit was about 1.7 logMAR, which changed to approximately 0.98 logMAR at the final visit.

Complications occurred in 70 episodes, including persistent epithelial defect in 38 cases, (30%), IOP elevation in 15 (12%) and corneal perforation in 12 (10%). Additionally, the researchers noted poor outcomes in 46 of 75 episodes (61%).