Abstract
Purpose: :
To determine the ability of Confocal Scanning Laser Ophthalmoscope (SLO), Heidelberg Retina Tomograph (HRT) and Scanning Laser Polarimeter (GDx-VCC) to detect optic nerve neuropathy and loss of the retinal nerve fiber layer (RFNL) previous the development of retinopathy in in patients with type I diabetes.
Methods: :
Comparative cross-sectional study. Fifty eyes of 50 healthy subjects and 50 eyes of 50 patients with type I diabetes mellitus were studied. Ophthalmic examination of diabetic patients showed no retinopathy. One eye per patient was randomly selected for the study. The nerve fiber layer thickness was measured using polarimetry (GDx-VCC) (NFA, Laser Diagnostic Technologies Inc, San Diego, CA, USA) and with Optical Coherence Tomography OCT (OCT2: Carl Zeiss Meditec, Dublin, California, USA). The optic disc was measured with HRT3 (HRT3: Heidelberg Engineering, Dossenheim, Germany).
Results: :
The control group was formed by 16 women, 34 men, aged 24-40 yr (mean 28.89 ±4.68). Diabetic patients were 16 women and 34 men, aged 25.56 yr (±10.49). Mean period from the onset of diabetes was 12.8 years (SD 9.40). None of the diabetic group had changes at the fundus examination. No differences were found in GDx or OCT measuremens between control and diabetic group. We did found differences in HRT measurements including linear cup/disc ratio, cup shape measure, rim area, rim volume, height variation contour, and mean RNFL thickness.
Conclusions: :
HRT can detect optic disc topography abnormalities in type I diabetes mellitus patients before the development of diabetic retinopathy. Neither GDx or OCT are able to find differences in the retinal nerve fiber layer thickness in diabetic patients without retinopathy. These data support the importance of the neuropathy in diabetic patients and the need of increasing our knowledge about its pathogenesis and risk factor.
Keywords: diabetes • optic nerve • nerve fiber layer