Abstract
Purpose: :
The cup area plays an important role in glaucoma diagnostic. The disc size is one marker to evaluate its pathologic value. In our study we compared the disc sizes measured by indirect ophthalmoscopy (iO) and by Heidelberg Retina Tomography (HRT).
Methods: :
57 eyes underwent an examination by 60D-, 78D-, 90D- and super field NC (Volk) lenses. The vertical and horizontal disc diameters were measured by Haag-Streit-slitlamp. An ellipse formula (horizontal disc diameter x vertical disc diameter x π/4) was used to calculate the disc area. The same eyes were examinated by HRT. The precision of the ophthalmoscopic estimate was checked and clarified by Bland-Altman plots.
Results: :
The results of the disc estimate compared to the HRT measurements were: 0.119 ± 0.51 mm² (60D Volk lens), 0,224 ± 0.57 mm² (78D lens), 0,10 ± 0.51 mm² (90D lens) and -0,07s ± 0.47 mm² (Superfield NC Volk lens). Only the 78 D lens showed significant differences compared with the HRT (Student-T-test; P = 0,004). The P-values of the 60 D, 90 D und Superfield lenses were 0,083, 0,147 and 0,257.
Conclusions: :
To postulate a statement about the disc size by indirect ophthalmoscopy the 90D lens showed the smallest differences and is the most suitable one. In constrast the 78D lens showed the greatest deviation.
Keywords: optic disc • imaging/image analysis: clinical