PURPOSE: To compare central corneal thickness (CCT) as measured by dual rotating Scheimpflug camera (Galilei), anterior segment optical coherence tomography (AS-OCT), and ultrasound pachymetry (USP). METHODS: The measurements of CCT using a dual rotating Scheimpflug camera, AS-OCT, and USP in 40 eyes of 20 healthy subjects were compared. RESULTS: The average measurements of CCT by dual rotating Scheimpflug camera, AS-OCT, and USP were 538.10 +/- 31.36 microm, 536.20 +/- 31.21 microm, and 541.93 +/- 34.93 microm, respectively. The CCT measurement by USP was statistically significantly thicker than by the dual rotating Scheimpflug camera and AS-OCT (p = 0.017, p = 0.001, respectively). There was no significant difference between the dual rotating Scheimpflug camera and AS-OCT (p = 0.054). A significant linear correlation was observed between the dual rotating Scheimpflug camera, the AS-OCT, and the USP (r > 0.900, p < 0.001). CONCLUSIONS: The results of the 3 methods have significant correlation with each other, but the measurement by USP was significantly thicker than the dual rotating Scheimpflug camera and AS-OCT. Therefore, CCT should be interpreted in the context of the instrument used.
Eye ; Tomography, Optical Coherence

No abstract available.
Tomography, Optical Coherence*

PURPOSE: To compare the efficacy of time domain (TD) and spectral domain (SD) optical coherence tomography (OCT) in determining vitreomacular interface (VMI). METHODS: VMIs were evaluated with TD and SD OCT images crossing the fovea horizontally in 69 eyes (mean age 52.7 +/- 15.4 years) and were classified as follows: (1) no vitreomacular separation (VMS), (2) incomplete VMS, and (3) unknown. RESULTS: In TD OCT, no VMS was observed in 2 eyes (2.9%), incomplete VMS in 2 eyes (2.9%), and unknown in 65 eyes (94.2%). In SD OCT, no VMS was observed in 31 eyes (45.0%), incomplete VMS in 13 eyes (18.8%), and unknown in 25 eyes (36.2%). In 31 eyes with no VMS on SD OCT, 29 eyes (93.5%) presented unknown on TD OCT (p<0.0001). In 13 eyes with incomplete VMS on SD OCT, 2 eyes (15.4%) showed incomplete VMS and 11 eyes (84.6%) showed unknown on TD OCT (p<0.0001). TD OCT was also non-informative in all 25 eyes with unknown on SD OCT. CONCLUSIONS: SD OCT allows better visualization of VMI than TD OCT, especially in patients with no VMS.
Humans ; Tomography, Optical Coherence*

PURPOSE:To compare the repeatability and agreement of macular thickness measurements using time domain (TD) optical coherence tomography (OCT) and spectral domain (SD) OCT in normal subjects. METHODS: Thirty-four normal subjects were included. Three consecutive macular measurements were taken with TD OCT and SD OCT. Total and regional macular thickness and total macular volume obtained by the two OCTs were compared. Within-subject standard deviation (Sw), coefficient of variation (CVw), and the intraclass correlation coefficient (ICC) were calculated to evaluate repeatability. The agreement was examined with Bland Altman plots. The correlation was also evaluated with Pearson correlation coefficients and multiple regression analysis. RESULTS: Sw for foveal thickness, total macular thickness, and total macular volume were 11.53 microm, 7.58 microm, and 0.48 mm3 for TD OCT and 6.69 microm, 2.55 microm, and 0.09 mm3 for SD OCT, respectively. The values for SD OCT were consistently lower, and this result was statistically significant. The range of the respective CVw and ICC values were 1.10~2.78% and 0.78~0.96% for TD OCT, and 0.29~0.94% and 0.92~0.99% for SD OCT, respectively. The SD OCT showed better repeatability for macular thickness measurements(all with p< or =0.001). The spans of 95% limits of agreement for foveal thickness, total macular thickness, and total macular volume were 67.94 microm, 29.01 microm, and 0.98 mm3, respectively. The Pearson correlation coefficient of foveal thickness, total macular thickness, and total macular volume between the two OCT's was statistically significant. CONCLUSIONS: Although both OCTs are reliable for macular thickness measurements, SD OCT shows better repeatability compared with TD OCT. Although macular thickness measurements obtained from the two OCTs can not be used interchangeably due to low agreement by different standards of measurement, there was a statistically significant correlation between the two OCT's.
Tomography, Optical Coherence

Humans ; Tomography, Optical Coherence

Objective: To describe changes in the retinal-nerve-fiber layer (RNFL) in patients diagnosed with ethambutol toxic optic neuropathy (ETON) using optical coherence tomography (OCT). Methods: Ophthalmological examinations were performed in 3 patients diagnosed with ETON. Visual acuity (VA), contrast sensitivity, color vision testing, slitlamp examination, applanation tonometry, dilated funduscopic examination, fundus and disc photography, automated perimetry and OCT were performed. Results: Three patients with ETON had VA ranging from 20/150 to counting fingers (CF). They were unable to resolve contrast sensitivity and discriminate fingers (CF). TWo patients with VA of CF in both eyes had RNFL thinning of 48.8% and 49.5%. A third patient 3 with VA of 20/150 in both eyes showed RNFL thickening of 14.10%. Conclusion: The results suggest that OCT may be useful ancillary procedure in early detection and monitoring of ophthalmological changes due to ETON.
Tomography Optical Coherence

No abstract available.
Tomography, Optical Coherence

Objective: To determine the presence of iridotrabecular contact (ITC) and compare the changes in anterior chamber angle (ACA) measurements in room lights-on and lights-off conditions using the anterior segment optical coherence tomography (AS-OCT) in eyes diagnosed as primary angle closure suspects (PACS) by gonioscopy. Methods: This is a retrospective review of 144 eyes of 79 patients (70 females, 9 males) with PACS. All eyes were imaged using the Visante® time-domain AS-OCT (Carl Zeiss Meditec, Dublin, CA). Each eye was imaged twice; the first scan was done with the room lights on followed by a second scan done after turning the room lights off for 2 minutes. The principal outcome measure was the presence of ITC in either lighting condition. Other angle metrics that were assessed included anterior chamber depth (ACD), angle opening distance (AOD), trabecular-iris space area (TISA), and scleral spur angle (SSA). Presence of ITC and differences in the angle metrics between the 2 lighting conditions were then analyzed using the t-tests and logistic regression. Results: ITC was present in 36.8% (53) of the study eyes. Twenty percent (20%) of the study eyes (29) did not initially exhibit ITC in the lights-on phase but developed ITC when imaged with the lights off. Persistent ITC was seen in 16.6% (24 eyes) in both lighting conditions. ITC occurred in 52.2% of the eyes with ACD less than 2.18 mm. Logistic regression showed that there is a 91% decrease in the odds of having ITC in lights-off condition for every millimeter of ACD increase. Age was not associated with the occurrence of ITC in the lights-off condition. All other analyzed parameters decreased significantly in the lights-off condition (p<0.05) except for the ACD, nasal TISA-500, and temporal SSA. Conclusions The presence of ITC is a well-established characteristic of eyes with angle closure. In eyes with PACS, detection of ITC may be enhanced with AS-OCT imaging in lights-off condition.
Tomography, Optical Coherence

Tomography, Optical Coherence

Objective: To determine the accuracy of the optic nerve head (ONH) and retinal nerve fiber layer (RNFL) parameters using the Stratus OCT in diagnosing glaucoma among Filipino patients and to determine the validity of the OCT measurements compared with a reference standard. Methods: Glaucoma suspects were recruited consecutively from patients undergoing diagnostic tests. The results of the Stratus OCT fast RNFL protocol were analyzed against the independent assessment by glaucoma experts who were blinded. Outcomes included RNFL thickness values of ≤5 percentile and ≤1 percentile of the normative database for each RNFL sector, quadrant, and for the average RNFL thickness. Estimates of diagnostic accuracy with 95% confidence intervals were calculated. Results: A total of 119 subjects assessed as glaucoma and 397 subjects assessed as normal were included in the analysis. Using the best categorical criterion for abnormality (average RNFL thickness of ≤1 percentile of the normative database), the OCT had a specificity of 98% (95% CI 96 - 99) and a sensitivity of 37% (95% CI 28 - 46). The criterion with the highest sensitivity was the presence of at least one sector with thickness at ≤5 percentile. Conclusion The Stratus OCT demonstrated a specificity of 98% and a sensitivity of 37% for the diagnosis of glaucoma using as a criterion an average RNFL thickness of ≤1 percentile of the normative database. It was a poor screening test for glaucoma suspects, although it showed some promise as a confirmatory test.
Glaucoma ; Tomography, Optical Coherence