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Abstract #24296 Published in IGR 11-3
Measurement of the Disc Area by Indirect Ophthalmoscopy
Haustein M; Schmidt E; Sporl E; Pillunat LE; Bohm AGOphthalmologe 2009; 106: 141-148
PURPOSE: The aim of this study was to assess the accuracy of measuring the optic disc area by indirect ophthalmoscopy. Patients and methods: In a prospective clinical trial, 57 eyes of 29 subjects (age 57.3±12.1 years) were examined. The refractive error was -0.67(plus or minus)2.69D (+3.75D to -8D).The vertical and horizontal disc diameters (DD) were measured using a Haag-Streit slit lamp and 60D-, 78D-, 90D-, and Super Field lenses (Volk Optical, Mentor, USA). Afterwards the disc area was calculated by an ellipse formula (horizontal DD null vertical DD null π/4). The magnification factor given by the manufacturer was taken into account for each lens: 1.15null (60D lens), 0.93null (78D lens), 0.76null (90D lens), and 0.76null (Super Field lens), respectively. As reference for the disc size, the same eyes were examined by HRT II (Heidelberg Engineering, Heidelberg, Germany). Bland-Altman plots were used to assess the agreement between measurements obtained by indirect ophthalmoscopy and HRT. RESULTS: The results of the disc estimate compared with the HRT measurements were as follows: 0.119 ±0.51 mm2 (60D lens), 0.224 ±0.57 mm2 (78D lens), 0.10 ±0.51 mm2 (90D lens), and -0.07 s ±0.47 mm2 (Super Field lens). Differences were not statistically significant for the 60D (p=0.083), 90D (p=0.147), or Super Field lenses (p=0.257). However, the difference between the 78D lens and HRT was statistically significant (Student's t-test; P=0.004). CONCLUSION: Measuring the disc size by indirect ophthalmoscopy is possible. The 90D lens showed the smallest and the 78D lens the largest deviation.
Dr. M. Haustein, Universitatsaugenklinik, TU Dresden, Fetscher Strasse 74, Dresden, Germany. michael.haustein@uniklinikum-dresden.de
Classification:
6.3.2 Posterior segment (Part of: 6 Clinical examination methods > 6.3 Biomicroscopy (slitlamp))
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
