Biomedical subjects

Rabia Gurses-Ozden

Publications and source records attributed to Rabia Gurses-Ozden.

2 recordsLinked to original sources

PubMed2004

Effect of pupillary dilation on retinal nerve fiber layer thickness measurements using optical coherence tomography.

PURPOSE: To evaluate the effect of pupillary dilation on retinal nerve fiber layer thickness (RNFL) measurements using optical coherence tomography (OCT-3). METHODS: Randomly chosen eyes of healthy individuals were scanned before and after pupillary dilation by two trained operators (R.G.O., R.V.) using OCT-3 (Carl Zeiss Meditec, Inc., Dublin, CA). Fast and regular RNFL (256 A-scans) OCT-3 protocols (software version A1.1) were used in each scanning session. RNFL thickness measurements before and after dilation were compared. RESULTS: Ten eyes of 10 subjects (6 females, 4 males) were enrolled. Mean age was 32.0 +/- 11.2 years (range, 21 to 52 years). Mean pupillary diameter before and after dilation was 2.9 +/- 0.6 mm and 7.6 +/- 0.8 mm, respectively (P < 0.0001, paired t-test). There was no significant difference in RNFL thickness measurements before and after dilation using both fast and regular RNFL protocols (P > or = 0.05 for all comparisons, paired t-test). Mean coefficients of variation for mean RNFL thickness measurements were 15.3% before and 13.7% after dilation for operator 1; and 10.8% before and 12.7% after dilation for operator 2 for the fast RNFL protocol and 11.3% versus 10.4% and 12.9 versus 11.1%, respectively, for the regular RNFL protocol. CONCLUSION: Pupillary dilation is not necessary in all subjects to obtain reproducible RNFL thickness measurements using OCT-3.

Adult↗

PubMed2004

Scanning protocol choice affects optical coherence tomography (OCT-3) measurements.

PURPOSE: To determine the optimal OCT-3 scanning protocol. METHODS: Normal subjects, ocular hypertensive, and open-angle glaucoma patients were enrolled. The "fast" RNFL scan protocol consists of 3 consecutive circular scans, each containing 256 A-scans obtained in a single 1.92 second session. The "regular" RNFL scan protocol contains 3 separate circular scans, each of which consists of 512 A-scans and is obtained in 1.28 seconds (total 3.84 seconds). A customized 256-point scan was created from the 512-point "regular" RNFL scan by extracting the RNFL measurements from every second point. Mean RNFL thickness measurements and mean coefficients of variation (CV) were calculated for each of the scan types. RESULTS: Thirty-one eyes with visual field defects (31 glaucoma eyes) and 30 eyes with normal fields (10 normal and 20 ocular hypertensive eyes) were enrolled. There was no difference in RNFL thickness or CV between fast, regular, or customized RNFL scans in the eyes with VF defects (P > 0.05 for all comparisons). Although eyes with normal fields showed no difference in CV between fast, regular, and customized RNFL scans (P > 0.05 for all comparisons), there was a thicker RNFL measurement using the fast RNFL scan (P = 0.01). CONCLUSIONS: Optimal sampling density for OCT-3 assessment of parapapillary RNFL thickness is not more than 256 axial determinations. Although both scanning protocols have good reproducibility, the scanning protocol should remain constant during serial OCT-3 evaluation.

Adult↗