Measurement of optic disc size and rim area with spectral-domain OCT and scanning laser ophthalmoscopy

• Published in: Investigative ophthalmology & visual science Vol. 53; no. 8; pp. 4519 - 4530
• Main Authors: Moghimi, Sasan, Hosseini, Hamid, Riddle, Jay, Lee, Gina Yoo, Bitrian, Elena, Giaconi, JoAnn, Caprioli, Joseph, Nouri-Mahdavi, Kouros
• Format: Journal Article
• Language: English
• Published: United States 09.07.2012
• Subjects: Female; Glaucoma - diagnosis; Humans; Male; Middle Aged; Ophthalmoscopy - methods; Optic Disk - cytology; Prospective Studies; Reference Values; Reproducibility of Results; Tomography, Optical Coherence - methods
• ISSN: 1552-5783; 1552-5783
• DOI: 10.1167/iovs.11-8362

To compare optic disc and neuroretinal rim area measurements from spectral-domain optical coherence tomography (SD-OCT) to those from confocal scanning laser ophthalmoscopy. Seventy-one eyes from 43 normal subjects or suspected/definite glaucoma patients were prospectively enrolled. All subjects had biometry with the IOLMaster and disc/retinal nerve fiber layer imaging with Cirrus SD-OCT (Optic Disc Cube 200×200) and Heidelberg Retina Tomograph (HRT). Uncorrected disc and rim areas and measurements corrected for eye magnification with Bennett's formula (AL-corrected measurements), along with 30° sectoral rim areas, vertical cup-to-disc ratio (VCDR), and cup volume, were compared between the two devices. The median (range) axial length (AL) was 24.2 mm (22.4-27.7 mm). Mean keratometry-corrected HRT disc area measurements were larger than AL-corrected HRT and SD-OCT measurements (P < 0.001 for both) and the difference was a function of keratometry measurements (K-readings). The AL-corrected HRT disc area and uncorrected/corrected Cirrus disc areas were not significantly different (P > 0.481). HRT rim area was larger than Cirrus measurements (P < 0.001) and the difference decreased with decreasing rim area. HRT VCDR and cup volume were significantly smaller than Cirrus measurements (P < 0.001). The correlations for sectoral rim areas between the two devices were moderate at best (intraclass correlation coefficients = 0.12-0.65). HRT overestimated optic disc area as compared to SD-OCT. A portion of the difference in HRT and SD-OCT disc measurements is due to HRT's magnification correction algorithm. Rim area measurements from HRT were larger than from SD-OCT, likely a result of different definitions for the reference plane and differences in disc area measurements. Disc parameters from the two devices are not interchangeable.