Abstract :
Context: High myopia is a risk factor for a number of retinal pathologies. OCT is very useful in eyes with
high myopia and allows the detection of subtle macular changes that are otherwise undetectable.
Aim: To evaluate relationship between the axial length, refractive error and macular thickness in subjects
with high myopia.
Study Design: Cross sectional observational single centric study.
Materials and Methods: 50 diagnosed patients of high myopia(refractive error>= -6 dioptres and/or axial
length>=24 mm) along with a control of 50 emmetropic patients were included. Patient’s anterior segment
evaluation was done by slit lamp. Detailed fundus evaluation was done with indirect ophthalmoscopy
and with 78 Dioptre lens along with measuring BCVA (Best corrected Visual Acuity). Axial length
was measured using contact biometry. OCT was performed with TOPCON SD-OCT. Average macular
thickness, central foveal thickness and total macular volume measured using 3D macula scan of all the
cases and controls.
Statistical Analysis: Unpaired t test.
Results: The mean axial length was 27.40 mm among cases (SD0.99) and 22.84 mm among controls
(SD0.422). The mean macular volume in cases was 6.90 and in controls was 7.82. The macular
volume decreased with increasing axial length (r=-0.673) and increasing spherical equivalent (r=-
0.035). The average macular thickness was inversely correlated with axial length (r=-0.605) and directly
correlated with spherical equivalent (r=-0.049).The mean central subfield foveal thickness was 170.10 mm
amongcases and 158.34mm among controls. The axial length and central foveal thickness were found to
be positively correlated (r=0.727).
Conclusion: Average macular thickness and total macular volume are inversely correlated to the degree of
myopia, whereas central foveal thickness is positively correlated to the degree of myopia.
Keyword :
High myopia, Macular thickness, Macular volume, OCT.