Purpose:
High myopia is believed to be associated with earlier macular involvement in glaucomatous optic neuropathy. The purpose of the study is to evaluate the association between myopic refractive error and macular thickness in normal tension glaucoma (NTG) with myopia of various degrees.
Methods:
One hundred eighty-four eyes of 184patients with NTG were selected from the patient database of the Gifu University Hospital, Japan in this retrospective study. The selection criteria were: established diagnosis of NTG, visual acuity at least 20/25, no ocular diseases affecting visual field except glaucoma, no funduscopically apparent macular abnormality, glaucomatous visual field change detected by the HFA C10-2 program, reliable visual field available and reliable optical coherence tomography (OCT) images using Macular Cube 200x200 mode (Cirrus-OCT, Zeiss-Meditec.). The subjects were divided into three groups; high myopia (spherical equivalent (SE) <-6.0D: n=102), moderate myopia (-3.0D>SE>-6.0D: n=43), and mild or no myopia (SE>-3.0D: n=39). The correlation between total deviation (TD) of the centralmost four test locations of HFA C30-2 and the corresponding retinal thickness measured by OCT were evaluated.
Results:
The average macular thickness in the area above the fovea was 297.44±25.29µm, 298.58±24.15µm, and 306.28±18.21µm in the high myopia, moderate myopia, mild or no myopia groups (figure). The average macular thickness in the area below the fovea was 280.84±21.19µm, 286.21±21.38µm, and 292.51±21.41µm in the high myopia, moderate myopia, mild or no myopia groups. The distribution of TD and macular thickness was not different among the three subject groups in four centralmost regions of the macula.
Conclusions:
This study has not confirmed any significant associations between myopia and functional/structural changes in the macula of NTG.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • myopia • macula/fovea