Abstract
Purpose::
To compare retinal nerve fiber layer (RNFL) measurements made with two different protocols of Stratus optical coherence tomography (OCT) in patients with band atrophy (BA) of the optic nerve and in normal controls.
Methods::
The RNFL of 38 eyes (19 with BA and 19 normals) was measured using two OCT scan protocols: (1) the Fast RNFL thickness (3.4) scan (with resolution of 256 scans points) and the Regular RNFL thickness (3.4) scan (with resolution of 512 scans points). The two sets of measurements were compared.
Results::
With the Fast RNFL protocol, the peripapillary RNFL thickness (mean ± SD in µm) in eyes with band atrophy measured 62.33 ± 11.48; 80.26 ± 26.66; 37.36 ± 7,57; 89.53 ± 16.39 and 41.89 ± 11.57 corresponding to the total RNFL average, superior, temporal, inferior and nasal quadrants, respectively. With regular protocol the corresponding measurements were 60.77 ± 10.40; 76.95 ± 25.95; 38.84 ± 11.38; 82.31 ± 16.91 and 42.89 ± 7.46. There was no significant difference between measurements for both protocols. There was a strong correlation (R > 0,75) between the two sets of measurements, except for those from the nasal quadrant and the 30-degrees segments located at the 3, 4 and 9 o’clock position. In normal eyes, the average RNFL thickness measurement with the regular protocol was significantly smaller than with the fast protocol buy there was no significant difference in other comparisons. All RNFL measurements with both the regular and the fast protocol were significantly different in eyes with band atrophy of the optic nerve when compared to normal eyes.
Conclusions::
Although the fast protocol average RNFL thickness measurement was significantly higher than with the regular protocol, there was no significant difference between the two sets of measurements in eyes with BA of the optic nerve. Both scans protocols were able to differentiate eyes with BA from normal eyes and demonstrated a strong correlation, except for the measurements from the nasal quadrant and the 30-degrees segments, located at 3, 4 and 9 o’clock position. Since such areas are the one with the thinnest RNFL, future studies are necessary in order to determine which scan protocol will discriminate better eyes with BA from normal eyes.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • neuro-ophthalmology: optic nerve • retina: proximal (bipolar, amacrine, and ganglion cells)