Abstract
Purpose
To evaluate the alterations in mean central choroidal, central macular, and disk retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography (OCT) during Valsalva maneuver among patients with high refractive errors.
Methods
A total of 60 high myopic (≥-6.0 D) and 50 high hyperopic (≥ + 3.0 D) eyes of 58 patients aged 19-65 years with visual acuity of 20/20 and without any ophthalmologic or systemic diseases were evaluated by OCT before and after the Valsalva maneuver. The choroidal thickness was measured with enhanced depth imaging OCT method. Central macular thickness, disk RNFL thickness, and axial length were also assessed.
Results
Mean choroidal thickness increased significantly from 275.0 ± 27.2 μm at rest to 279.8 ± 31.6 μm after Valsalva maneuver in high myopic patients, and from 308.2 ± 27.3 μm to 313.6 ± 28.5 μm in high hyperopic patients (p<0.01 for each). A significant negative correlation of the choroidal thickness was noted with axial length (r = -0.509, p<0.01) and age (r = -0.224, p = 0.01) in the overall study population. Mean central macular thickness was 242.9 ± 44.4 μm and 254.0 ± 22.8 μm, while mean disk RNFL thickness was 81.6 ± 12.4 μm and 98.4 ± 13.3 μm in high myopic and hyperopic patients, respectively. Valsalva maneuver was not associated with significant change in central macular or disk RNFL thickness.
Conclusions
Significant association of Valsalva maneuver with an increase in choroidal thickness was noted among patients with high degree of myopia and hyperopia. Our findings emphasize the likelihood of increase in choroidal volume due to venous distension to be responsible for the increase observed in choroidal thickness after Valsalva maneuver.
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