V 346
Seven-year follow-up of localized retinal nerve fibre layer defects with the Heidelberg Retina Tomograph HRT
R. O. W. Burk, P. J. Airaksinen, A. Tuulonen
Laser Scanning Tomography has been shown to be an accurate and reproducible method to analyze the 3-D topography of the optic nerve head quantitatively . In addition, this technique allows for imaging of the retinal nerve fibre layer (RNFL). The image quality depends upon the transparency of the optic media. We addressed the question whether localized RNFL defects as evaluated by red free fundus photography and laser scanning tomography could be re-evaluated after a follow-up period of over 7 years.
Method: 8 eyes of 8 patients with localized RNFL-defects as documented by RNFL-photography were evaluated using Laser Scanning Tomographie (HRT I) over a follow-up period of 90 months. The optic disk was documented in 10 and 15 degree field with an individually adjusted scan depth 2.5 to 4.0 mm. The parapapillary RNFL-defects were focussed and imaged with a reduced scan depth of 1-2 mm. Patient mean age was 68 ± 7.8 years (53 bis 80 years).
Results: In all eyes under investigation, the localized RNFL defects could be reproducibly documeted. In 4 eyes, the width of the defect as determined at a distance of 1 mm to the optic disk margin increased during the follow-up period. Two of these eyes with progression showed in addition new defects, which were confirmed by red free fundus photogfraphy. In four eyes, no significant changes in defect width were detected.
Discussion: The technique of Laser Scanning Tomographyy can be used to follow the progression of documented RFNL-defects and to detect new localized RNFL-defects as well. The presence of progressing nerve fibre layer defects might be considered an early sign indicating activity of the glaucomatous damage.
Universitäts-Augenklinik , INF 400, D-69120 Heidelberg
Department of Ophthalmology, University of Oulu, FIN-90220, Finnland