Specifity of optic disc evaluation in healthy subjects with large optic discs and physiologic cupping using confocal scanning laser ophthalmoscopy

• Published in: Klinische Monatsblatter fur Augenheilkunde Vol. 231; no. 2; p. 164
• Main Authors: Plange, N, Hirsch, T, Bienert, M, Remky, A
• Format: Journal Article
• Language: German
• Published: Germany 01-02-2014
• Subjects: Equipment Design; Equipment Failure Analysis; Humans; Image Interpretation, Computer-Assisted - instrumentation; Image Interpretation, Computer-Assisted - methods; Microscopy, Confocal - instrumentation; Microscopy, Confocal - methods; Ophthalmoscopy - methods; Optic Disk - cytology; Organ Size; Reference Values; Reproducibility of Results; Sensitivity and Specificity; Software; Software Validation
• ISSN: 1439-3999
• DOI: 10.1055/s-0032-1328094

Imaging methods of the optic nerve head appear to have an increasing impact in glaucoma diagnosis. The aim of this study is to evaluate the specifity of the Heidelberg Retina Tomograph (software version 1.7 and 3.0) in subjects with physiological cupping and large optic discs.
27 eyes of 27 subjects (mean age 41.3 ± 15.8 years) with bilateral physiological cupping and large optic discs (vertical cup-to-disc-ratio > 0.3, optic disc area 2.48 ± 0.45 mm2, max. 3.54 mm2) were included in a clinical study. All subjects had an intraocular pressure < 22 mmHg, physiological cupping by funduscopy and no nerve fibre layer defects (Scanning Laser Ophthalmoscope, Rodenstock, Germany). Standard achromatic perimetry (Humphrey Field Analyzer, Humphrey-Zeiss, 24/2 SITA or full threshold), short-wavelength automated perimetry (Humphrey Field Analyzer, Humphrey-Zeiss), and frequency doubling technology (FDT, Humphrey-Zeiss) revealed no visual field defects. Optic disc imaging was performed in all subjects using the Heidelberg Retina Tomograph II (HRT). Optic disc images were transferred to the software-update of the HRT 3 (Version 3.0, Heidelberg Engineering). Specifity was calculated using the Moorfields regression analysis (MRA, software version 1.7 and 3.0) and the glaucoma probability score (GPS analysis) using all disc sectors and omitting the nasal and 3 nasal sectors.
Specifity of the MRA (software version 1.7) was 66.6 % (most specific criteria), and 22.2 % (least specific criteria). Specifity of the MRA (software version 3.0) was 33.3 % (most specific criteria), and 14.8 % (least specific criteria), whereas specifity of the GPS analysis was 37.0 % (most specific criteria), and 11.1 % (least specific criteria). When the nasal sectors were omitted for analysis, specifity increased for the MRA analysis, but not for the GPS analysis.
Specifity of the MRA was unsatisfactory using the software version 1.7 and 3.0 in subjects with large optic discs and physiological cupping when the nasal sectors were included in the analysis. The observer-independent GPS analysis did not improve the results in these subjects.