Determination of retinal surface area

摘要

Previous attempts at determining retinal surface area and surface area of the whole eye have been based upon mathematical calculations derived from retinal photographs, schematic eyes and retinal biopsies of donor eyes. 3‐dimensional (3‐D) ocular magnetic resonance imaging (MRI) allows a more direct measurement, it can be used to image the eye in vivo, and there is no risk of tissue shrinkage. The primary purpose of this study is to compare, using T2‐weighted 3D MRI, retinal surface areas for superior‐temporal (ST), inferior‐temporal (IT), superior‐nasal (SN) and inferior‐nasal (IN) retinal quadrants. An ancillary aim is to examine whether inter‐quadrant variations in area are concordant with reported inter‐quadrant patterns of susceptibility to retinal breaks associated with posterior vitreous detachment (PVD). Seventy‐three adult participants presenting without retinal pathology (mean age 26.25 ± 6.06 years) were scanned using a Siemens 3‐Tesla MRI scanner to provide T2‐weighted MR images that demarcate fluid‐filled internal structures for the whole eye and provide high‐contrast delineation of the vitreous‐retina interface. Integrated MRI software generated total internal ocular surface area (TSA). The second nodal point was used to demarcate the origin of the peripheral retina in order to calculate total retinal surface area (RSA) and quadrant retinal surface areas (QRSA) for ST, IT, SN, and style="fixed-case">IN quadrants. Mean spherical error ( style="fixed-case">MSE) was −2.50 ± 4.03D and mean axial length ( style="fixed-case">AL) 24.51 ± 1.57 mm. Mean style="fixed-case">TSA and style="fixed-case">RSA for the style="fixed-case">RE were 2058 ± 189 and 1363 ± 160 mm², respectively. Repeated measures class="small-caps">anova for style="fixed-case">QRSA data indicated a significant difference within‐quadrants (P < 0.01) which, contrasted with style="fixed-case">ST (365 ± 43 mm²), was significant for style="fixed-case">IT (340 ± 40 mm² P < 0.01), style="fixed-case">SN (337 ± 40 mm² P < 0.01) and style="fixed-case">IN (321 ± 39 mm² P < 0.01) quadrants. For all quadrants, style="fixed-case">QRSA was significantly correlated with style="fixed-case">AL (P < 0.01) and exhibited equivalent increases in retinal area/mm increase in style="fixed-case">AL. Although the differences between style="fixed-case">QRSAs are relatively small, there was evidence of concordance with reported inter‐quadrant patterns of susceptibility to retinal breaks associated with style="fixed-case">PVD. The data allow style="fixed-case">AL to be converted to style="fixed-case">QRSAs, which will assist further work on inter‐quadrant structural variation.