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L. Hefner, C. Jochmann, P. Wiedemann; Measurement of Retinal Thickness in Diabetic Maculopathy and in Exudative Age Related Macular Degeneration by OCT3 and HRT II . Invest. Ophthalmol. Vis. Sci. 2006;47(13):5727.
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© ARVO (1962-2015); The Authors (2016-present)
Until now the judgement of diabetic maculopathy and exudative age related macular degeneration (AMD) has relied on biomicroscopy and fluorescence angiography. Additional new techniques of examination such as optical coherence tomography (OCT3) and scanning laser topography (HRT II) allow a quantitative assessment of the central retinal thickness.
In 120 eyes of 68 patients with diabetic maculopathy and 120 eyes of 78 patients with exudative AMD the central retinal thickness was measuered by OCT3 and HRT II. We composed a topography map with the data of the OCT3 and edema maps with the data of the HRTII measurements. The measurement of the retinal thickness by OCT3 includes 128–512 points per each a–scan (6 scans per topography map= 768–3.072 points) the points in between are extrapolated and colourcoded. In the HRT II series of optical tomographs different layers of focal level (confocal measurement) are produced in a matrix of 384 x 384=147.456. With this data edema index maps were calculated.
Both the topography maps and edema inde maps detected the macular edemas seen ophthalmoscopically. The mean central retinal thickness measured with OCT3 in diabetic edema was 318±120µm and in exudative AMD 290±106µm. The mean edema index (e) measured with HRTII, was 2,01±0,80 in diabetic edema and 1,90±0,36 in exudative AMD. There was also good correlation between data measured by OCT3 and HRTII (diabetic edema r=0,67; exudative AMD r=0,66). The correlation between visual acuity and OCT3/HRTII measurements correspond (diabetic edema r= 0,38/0,41; exudative AMD r=0,41/0,34).
The measurement of retinal thickness in diabetic macular edema and exudative AMD by composing topographic maps with OCT in comparison to HRTII edema index maps corresponds to the ophthalmoscopic findings. In exudative AMD sometimes the poor ability of fixation diminishes the quality of data acquisition. Both methods are non–invasive examinations and valuable additions to the clinical examination.
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