D. F. Kiernan

Prospective Comparison of Cirrus and Stratus Optical Coherence Tomography for Quantifying Retinal Thickness

PURPOSE To compare Cirrus Fourier-domain optical coherence tomography (OCT) with Stratus time-domain OCT for imaging retinal diseases and quantifying retinal thickness (RT) of all nine OCT zones, central macular thickness, and average macular thickness in eyes with and without macular edema. DESIGN Prospective comparison between two OCT systems. METHODS RT measurements were performed in 120 eyes of 60 patients suspected of having increased retina thickness using both Stratus and Cirrus OCT on the same day. Twenty-one eyes had both 512 x 128 and 200 x 200 Cirrus cube scans done. RESULTS Data from 101 eyes (53 patients) were analyzed; 46 eyes (45.5%) had macular edema on clinical examination (Group 1), whereas 55 eyes (54.4%) had no clinical evidence of macular edema (Group 2). There was modest correlation between all thickness measurements in 909 zones and each group (range of Pearson correlation, 0.51 to 0.89) and average value was significantly greater when measured with Cirrus OCT for all eyes (mean difference, 43.2 microm; P < .0001). There were few measurement differences between different resolution Cirrus cube scans. CONCLUSIONS Cirrus OCT measures RT approximately 43 microm greater than Stratus OCT, which is likely attributable to Cirrus OCT detection of the outer band of the retinal pigment epithelium vs Stratus OCT detection of the inner/outer segment photoreceptor junction. All zones showed a wide degree of variability in correlation. Both Cirrus cube scans provide similar data. Future studies comparing these systems might consider utilizing average macular thickness values, which reflect macular volume and may provide more consistent measurements.

Multiple drug-resistant Alcaligenes xylosoxidans keratitis in a sanitation worker.

Purpose: To report a case of daily wear soft contact lens-associated keratitis caused by Alcaligenes xylosoxidans in a portable toilet sanitation worker. Methods: A previously healthy 30-year-old man presented with bilateral decreased vision, redness, and irritation, beginning 1 week earlier. The patient had been treated with moxifloxocin for 1 week before presentation without improvement. Bacterial staining cultures were performed from corneal scrapings, contact lenses, contact lens case, and solution. Preliminary culture results and antibiotic sensitivities were generated using an automated identification system. Positive results from the contact lens, case, and solution were confirmed using polymerase chain reaction (PCR). Results: The contact lenses, contact lens case, and solution cultures revealed heavy growth of A. xylosoxidans. These findings were confirmed by PCR. The organism was found to be resistant to aminoglycosides, fluoroquinolones, and cephalosporins. The patient was started on polymyxin B or trimethoprim. After 21 days of treatment, the infection completely resolved with a final spectacle-corrected visual acuity of 20/25. Conclusions: To our knowledge, this is the first case report of a corneal infection caused by A. xylosoxidans, which was isolated and identified from a contact lens, case, and solution using culture and PCR technique as well the first description of ocular surface disease resolution after the treatment with topical polymyxin B or trimethoprim. A. xylosoxidans should be considered as uncommon but potential pathogen capable of infectious spread through contaminated contact lens solution.