Purchase this article with an account.
C. A. Rasmussen, J. C. Peterson, T. J. Bunch, P. L. Kaufman, T. Nork; Stratus OCT 3 Scanning Resolution: Fast Scans vs Normal Scans in Mnkeys. Invest. Ophthalmol. Vis. Sci. 2007;48(13):2599.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To evaluate the feasibility of using the Stratus OCT system with monkeys and investigate quantitative differences in fast vs normal (higher resolution) scans.
Normal eyes from 11 cynomolgus monkeys were studied. Monkeys were anesthetized with a combination of intra-muscular ketamine and medetomidine, followed by inhalation isoflurane. Slit lamp exams were performed prior to scan acquisition. A 10mm plano contact lens was applied to ensure adequate corneal hydration. A Stratus OCT 3 system (Carl Zeiss Meditec, Dublin, CA) was used to acquire retinal nerve fiber layer (RNFL) map, RNFL thickness (3.4), macular thickness maps (Mac Map) and optic disc scans. Both fast and normal scans were taken during the same imaging session. Data are shown as mean±;sem, microns.
Mac Map and RNFL (3.4) values varied little between scan types. RNFL map values were higher in the fast scans but not significantly so. Optic disc scans showed the most variability, with both scan types subject to errors detecting the edge of the RPE and the anterior surface of the RNFL. Mac Map: Mean quadrant values were 250.3±;5.05 and 250.87±; 4.82; total macular volume measurements were 6.97±;0.07 and 7.00±;0.07; mean coefficient of variation (COV) for the quadrant values was 0.06±;0.0022 and 0.06±; 0.0023; signal strength (Sig. St.) was 9.77±;0.11 and 9.73±;0.15 for normal and fast scans respectively. RNFL Map: Data output was in the form of 8 sector values around the disc, with both inner and outer values. Fast scans averaged a non-significant 4.47±;0.75 higher for the outer and 4.10±;0.92 for the inner sectors. Mean COV for the 8 inner and 8 outer RNFL values, was 0.14±;0.011 and 0.16±;0.013 for normal and 0.15±;0.013 and 0.18±;0.014 for fast scans. Mean Sig. St. was 9.36±;0.18 and 9.41±;0.17 for normal and fast scans respectively. RNFL (3.4): Average thickness values were 99.26±;1.95 and 100.43±;1.65; mean COV was 0.12±;0.01and 0.12±;0.02; Sig. St. was 10.0±;0.0 and 9.86±;0.07 for normal and fast respectively. Optic disc: COV ranged from 0.11 to 0.79 with means of 0.39±;0.05 and 0.45±;0.06 for normal and fast respectively. The highest COV was seen in the parameter cup/disk area ratio, 0.73 and 0.79, while the lowest was seen in the parameter disk area, 0.11 and 0.12, Sig. St. was 9.64±;0.12 and 9.55±;0.18, normal and fast respectively.
Although the higher resolution of the normal scans may reveal more qualitative anatomic details, both the fast and normal scans produced comparable quantitative measurements in these normal, healthy monkeys.
This PDF is available to Subscribers Only