Choroidal thickness measurements in young Saudi adult population: a cross-sectional study.

Aim: To determine the choroidal thickness (CT) in young healthy Saudi adults using spectral-domain optical coherence tomography (SD-OCT) with an automated CT segmentation software.

Methods: Fifty-eight young adults (total of 116 eyes), 39 males and 19 females participated in this study between the ages of 18 and 38y (mean 22.65±3.9y). All participants underwent ophthalmic screening examination, including the SD-OCT for measurements of CT in each quadrant egmented into five eccentric regions starting from the foveal region up to 4.5 mm towards the periphery.

Results: The choroid was thickest in the foveal region (central 1 mm, 300±60 µm) and began to progressively thinner beyond the parafovea (1.5-2.5 mm, 284±67 µm) towards the peripheral region (3.5-4.5 mm from the fovea, 254±83 µm). The superior choroid showed the thickest profile (309±57 µm), while the nasal choroid exhibited the thinnest (229±76 µm). The rate of the thinning with increasing eccentricity was more predominant in the nasal choroid, which thinned from the foveal region (294±58 µm) to the peripheral region (158±55 µm). The superior and inferior choroid did not show a statistically significant thinning with eccentricity (all >0.05). There was no statistically significant difference in the CT between gender, age, and laterality of the eyes (all >0.05). A significant association of myopia with thinner subfoveal choroid was observed (Pearson's, =0.37), and regression analysis showed that a 10.3 µm choroidal thinning for each diopter increase of myopia.

Conclusion: CT profile depends on eccentric and the quadrant. The CT profile across the measured area in the young Saudi adult population is comparable to other previous reports. Refractive error is critical for CT evaluation.