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meillat mathieu, Perle TUMAHAI, Mélanie Bidaut-Garnier, Guillaume Debellemaniere, Mathieu Flores, Michel Montard, Bernard Delbosc, Maher Saleh; Variation of cone density assessed by Adaptive Optics Retinal Camera with axial length. Invest. Ophthalmol. Vis. Sci. 2013;54(15):3434.
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© ARVO (1962-2015); The Authors (2016-present)
To assess macular cone densities changes with axial length (AL) and spherical equivalent (SE) using Adaptive Optics (AO).
Fifty-two eyes of 28 healthy adults under 50 years, with a visual acuity of 20/20, were imaged. Group 1 included myopic and group 2 non myopic eyes. All patients underwent a complete ophthalmologic examination, spectral-domain optical coherence tomography (SD OCT), and imaging with the RTX-1 Adaptive Optics (AO) device from Imagine eyes™ (Orsay, France). Mean cone density (cells/mm2) at a fixed distance from the fovea (1° nasally and temporally), spacing between cells (µ) and percentage of hexagonal cells calculated on Voronoi diagrams, were obtained by two masked graders using AODetect v. 0.1, the proprietary software of the device. Axial length was measured by using IOL Master® (Carl Zeiss. Meditec. USA).
In group 1 (n=22), AL was 25.17+-1.15 mm and SE -5+-2.73 D. In group 2 (n=30), AL was 23.09+-0.87mm (p<0.05) and SE 1.23+-2.05 D (p<0.05). The mean age was 30.55 with no difference between groups (p<0.05). Cone density was lower in group 1 (23251+-1845 cells/mm2 vs 25419 +-2443 cells mm2 in group 2, t test, p=0.001). Spacing between photoreceptors was also higher in myopic eyes (7.47 +-0.52 µ vs 7.06 +-0.36 µ,t test, p=0.001). There was no difference in percentage of hexagonal cells between both groups. The cone density was inversely proportional to the axial length and the spherical equivalent (r2= 0.22,p=0.002 and r2=0.17 p=0.002, respectively). The multiple regression analysis showed that AL but not age contributed to the change in cone density (p=0.001).
Myopic subjects with a good visual acuity showed a lower cone density in the macular area and a higher spacing between cells, correlated to the axial length. Adaptive Optics could help understanding the pathological changes induced in the retina by the myopia.
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