A Case of Endogenous Streptococcus Mitis Endophthalmitis in a Patient with Staphylococcus Aureus Sepsis

PURPOSE: To report a case of endogenous endophthalmitis due to Streptococcus mitis in a patient with Staphylococcus aureus sepsis. CASE SUMMARY: A 77-year-old male complained of sudden visual loss and ocular pain in his right eye and was treated with intravenous antibiotics for Staphylococcus aureus sepsis. With a diagnosis of endogenous endophthalmitis, the patient received pars plana vitrectomy and intravitreal injection of antibiotics. Vitreous fluid was obtained before surgery, and the organism was identified as Streptococcus mitis. Twenty-one days after the surgery, intraocular inflammation was stabilized, and visual acuity was improved from light perception to 20/60. CONCLUSIONS: Appropriate sampling and culture of vitreous fluid are important for the diagnosis of endogenous endophthalmitis. The possibility that the causative organism of endogenous endophthalmitis may be different from the result of blood culture should be considered.

Low Limit for Effective Signal Strength in the Stratus OCT in Imperative Low Signal Strength Cases

PURPOSE: To determine the lowest limit of signal strength that is still effective for accurate analysis of optic coherence tomography (OCT) values, we investigated the reproducibility of OCT scans by signal strength (SS). METHODS: A total of 668 subjects were scanned for measurements of retinal nerve fiber layer (RNFL) thickness using the Stratus OCT twice on the same day. The variability of overall RNFL thickness parameters obtained at different SS was analyzed and compared by repeated-measures of ANOVA and Spearman's correlation coefficient. Values of the intraclass correlation coefficient (ICC) and variability (standard deviation) of RNFL thickness were obtained. The false positive ratio was analyzed. RESULTS: When SS was 3, the variability of RNFL thickness was significantly different (low ICC, high variability) in comparison to when SS was 4 or greater. Significant negative correlations were observed between variability in RNFL thickness and signal strength. The difference of variability of average RNFL thickness between SS 4 (4.94 microm) and SS 6 (4.41 microm) was 0.53 microm. CONCLUSIONS: Clinically, the difference of variability of average RNFL thickness between SS 4 and SS 6 was quite small. High SS is important, however, when signal strength is low due to uncorrectable factors in patients in need of OCT for glaucoma and retinal disease. Our results suggest that SS 4 is the lowest acceptable limit of signal strength for obtaining reproducible scanning images.