Beyond the choroid: investigating scleral and iris thickness in the pachychoroid disease spectrum

To compare scleral, iris, and choroidal thickness in central serous chorioretinopathy (CSC) and polypoidal choroidal vasculopathy (PCV) within the pachychoroid disease spectrum, relative to healthy controls.

Retrospective, case-control METHODS: Subfoveal choroidal thickness was evaluated using enhanced depth imaging (EDI) optical coherence tomography (OCT). Scleral thickness was measured 6 mm posterior to the scleral spur in four quadrants, while iris thickness was assessed at IT2000 (2000 µm from the scleral spur) in the nasal and temporal quadrants using anterior segment OCT (AS-OCT).

A total of 160 individuals participated, including 40 PCV patients, 40 CSC patients, and their respective control groups. Choroidal thickness was significantly greater in the PCV and CSC groups compared to controls (p =.001). Scleral thickness values were higher in both groups; in the CSC group, differences were significant in the superior (p =.007), nasal (p =.003), and temporal (p =.006) quadrants, whereas in the PCV group, although values were higher across all quadrants, these differences did not reach statistical significance (p =.020-.047). Iris thickness was significantly higher in the nasal and temporal quadrants (nasal: p<.001, p=.014, temporal: p=.015, p=.009). In the controls, choroidal and iris thickness decreased with age and were positively correlated, whereas these relationships were not observed in the case groups.

Choroidal, scleral, and iris thicknesses are increased in CSC and PCV patients compared to healthy controls. In the spectrum of pachychoroid disease, thick choroid is a known feature, however thick sclera and iris may also play an important role in the pathogenesis.