Abstract
Purpose:
To compare optic disc and neuroretinal rim area measurements from spectral-domain optical coherence tomography (SD-OCT) to those from confocal scanning laser ophthalmoscopy in myopic eyes.
Methods:
One hundred sixty-five eyes from 165 healthy subjects with mean spherical equivalent -5.24 +/- 4.2 D (range, -15.75 to -1.00 D) were analyzed. Optic disc measurements including disc area, rim area, cup volume were obtained with an optical coherence tomograph (Cirrus SD-OCT; Carl Zeiss Meditec Inc., Dublin, CA) and a confocal scanning laser ophthalmoscope (Heidelberg Retina Tomograph, HRT 2; Heidelberg Engineering, GmbH, Dossenheim, Germany). Bland-Altman plots were used to evaluate the agreement for each optic disc parameter. The effect of myopia status on difference of disc measurements between two instructments was evaluated by linear regression analysis.
Results:
The median (range) axial length (AL) was 25.6 mm (23.08-28.12 mm). Mean HRT disc area were larger than SD-OCT measurements (P < 0.001) and the difference was positively associate with axial length measurements. HRT rim area was larger than Cirrus measurements (P < 0.001) and the difference was not affect by myopia status. HRT cup volume were significantly smaller than Cirrus measurements (P < 0.001).
Conclusions:
HRT overestimated optic disc area and rim area as compared to SD-OCT. A portion of the difference in HRT and SD-OCT optic disc measurements is due to myopia status. Disc parameters from the two devices are not interchangeable.
Keywords: 550 imaging/image analysis: clinical