Central corneal thickness of Caucasians, Chinese, Hispanics, Filipinos, African Americans, and Japanese in a glaucoma clinic.

OBJECTIVE: To characterize the central corneal thickness (CCT) of Asian (Chinese, Japanese, and Filipino), Caucasian, Hispanic, and African American patients in a multiethnic glaucoma practice. DESIGN: Retrospective study (chart review). PARTICIPANTS: Glaucomatous (n = 600) and nonglaucomatous (n = 201) eyes of 801 patients examined in a San Francisco glaucoma clinic from June 2002 to April 2004 who met inclusion criteria were included in the study. The 6 racial (ethnic) groups represented in the study were Caucasian (n = 186, 23.2%), Chinese (n = 157, 19.6%), Japanese (n = 121, 15.1%), Hispanic (n = 116, 14.5%), Filipino (n = 114, 14.2%), and African American (n = 107, 13.4%). METHODS: Central corneal thickness was measured by means of ultrasound pachymetry in Asian (Chinese, Japanese, and Filipino), Caucasian, Hispanic, and African American participants with glaucomatous and normal eyes. The relationship between CCT and race was investigated using multivariate regression analyses, controlling for confounders. One eye of each of 801 participants was included for analysis. MAIN OUTCOME MEASURES: Correlation of mean CCT with race, glaucoma diagnosis, age, spherical equivalent, gender, and history of ocular surgery. RESULTS: The mean CCT of all participants was 542.9 mum. Central corneal thicknesses of Chinese (555.6 microm), Caucasian (550.4 microm), Filipino (550.6 microm), and Hispanic (548.1 microm) participants did not significantly differ. The CCT of Japanese participants (531.7 microm) was significantly less than that of Caucasians, Chinese, Filipinos, and Hispanics (all, P< or =0.001) and greater than that of African Americans (P = 0.03). African Americans had a CCT (521.0.0 microm) less than that of all races (P< or =0.05). Glaucoma suspects and patients with normal tension glaucoma (NTG), primary open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PEX), and chronic angle-closure glaucoma (CACG) had corneas significantly thinner than those of normal participants (P< or =0.004), whereas ocular hypertensives had significantly thicker corneas (P<0.0001). Among all participants, decreasing values of CCT were significantly related to older age (P<0.01). Less negative or more positive refractive errors, gender, and history of ocular surgery were not associated with changes in CCT (P = 0.38, P = 0.50, and P = 0.97, respectively). CONCLUSIONS: Studies examining individual Asian subpopulations in isolation suggest that differences in CCT may exist among different Asian groups. The results of this study indicate that CCT does, in fact, vary among Asian subpopulations; Japanese have thinner corneas than Chinese and Filipinos. Caucasians, Chinese, Hispanics, and Filipinos have comparable CCT measurements, whereas the corneas of African Americans are significantly thinner. Additionally, older individuals; glaucoma suspects; and participants with NTG, POAG, PEX, and CACG have thinner corneas. Ocular hypertensives, however, have thicker corneas.

Culture plate temperature and delayed incubation effect on bacterial recovery.

PURPOSE: To discover if initial culturing conditions (plate temperature and time delay to incubation) adversely influence the recovery of organisms associated with bacterial keratitis. METHODS: The rate of temperature equilibration of culture plates taken from a refrigerator and placed in an incubator and left on the desk was evaluated with a digital thermometer. A standard inoculum for each of five organisms (S. aureus, S. pneumoniae, P. aeruginosa, E. aerogenes, K. oxytoca) isolated from human bacterial keratitis was spread evenly on blood agar plates at refrigerator (Tcold; 4 degrees C), room (Troom; 24 degrees C), and incubator (Twarm; 37 degrees C) temperatures. The plates were then kept at room temperature for 0, 1, 3, 5, and 8 hours before overnight incubation at 37 degrees C (S. pneumoniae under microaerophilic conditions), and the number of colony-forming units was counted. RESULTS: Cold plates took at least 15 minutes in an incubator to attain room temperature, and up to an hour when left on the desk. Increased organism recovery was found comparing both Twarm and Troom plates (6.2 to 24.8% and 7.0 to 14.7%, respectively, P<0.001) to Tcold plates for all organisms except S. pneumoniae (P=0.057). Comparing Twarm plates to Troom plates demonstrated an increased recovery (P<0.001) for S. aureus. Delayed incubation resulted in decreased recovery for S. pneumoniae (P<0.001). CONCLUSIONS: Culture plates should preferably be warmed at least to room temperature before inoculation, as well as promptly incubated to increase bacterial recovery from cases of septic keratitis.