Friedrich-Alexander-Universität Erlangen-Nürnberg

Reliability of scanning laser polarimetry to measure the retinal nerve fibre thickness and to detect glaucoma

Reliability of scanning laser polarimetry to measure the retinal nerve fibre thickness and to detect glaucoma

Scanning laser polarimetry (SLP) is a commercially available method to measure the retinal nerve fibre layer (RNFL) thickness. However, there are some limitations of this method that lead to errors in some subjects. These errors can be described as atypical retardation pattern (ARP). The aim of this project was to measure the reliability of SLP to measure the RNFL distribution and to find the reason for errors and the appearance of ARP in SLP.

RNFL thickness was measured in normal subjects and glaucoma patients using SLP and spectral domain optical coherent tomography (OCT). OCT results are used as reference because they are not affected by ARP (Hoesl, Tornow et al. 2011). Choroidal thickness was measured using semiautomatic software (OCTSEG,

Our result show that at positions with ARP scanning laser polarimetry overestimates the RNFL thickness (Schrems, Laemmer et al. 2011). The reason for these ARP is reduced choroidal thickness in subjects that show ARP (Tornow, Schrems et al. 2011). Reduced choroidal thickness may result in an increased amount of confounding light getting to the SLP light detectors. The appearance of ARP is associated with a decrease in diagnostic accuracy for discriminating healthy and glaucomatous eyes by scanning laser polarimetry (Hoesl, Tornow et al. 2011).

Fig. 2. Circular OCT B-scans around the optic nerve head of two normal subjects. Choroidal thickness (between red and green lines) was measured using the software OCTSEG. Left: small choroidal thickness leads to errors in SLP. Right: thick choroidal thickness allows correct results of SLP. For details see (Tornow, Schrems et al. 2011) and (Schrems, Laemmer et al. 2011).

Hoesl, L. M., R. P. Tornow, W. A. Schrems, F. K. Horn, C. Y. Mardin, F. E. Kruse, A. G. Juenemann, R. Laemmer (2011). "Glaucoma Diagnostic Performance of GDxVCC and Spectralis OCT on Eyes With Atypical Retardation Pattern." J Glaucoma.


Schrems, W. A., R. Laemmer, L. M. Hoesl, F. K. Horn, C. Y. Mardin, F. E. Kruse, R. P. Tornow (2011). "Influence of atypical retardation pattern on the peripapillary retinal nerve fibre distribution assessed by scanning laser polarimetry and optical coherence tomography." Br J Ophthalmol 2011: DOI bjo.2010.190074 [pii] 10.1136/bjo.2010.190074.


Tornow, R. P., W. A. Schrems, D. Bendschneider, F. K. Horn, M. Mayer, C. Y. Mardin, R. Lammer (2011). "Atypical retardation patterns in scanning laser polarimetry are associated with low peripapillary choroidal thickness." Invest Ophthalmol Vis Sci 52(10): 7523-8.


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