Abstract
Purpose:
To determine and quantify choroidal thickness changes in patients affected by β-thalassemia syndromes with normal fundus appearance and with pseudoxanthoma elasticum (PXE)-like fundus changes.
Methods:
We performed subfoveal EDI-OCT scans in the right eyes of 120 consecutive patients with β-thalassemia syndromes, as well as in a control group of 35 healthy volunteers. Subfoveal choroidal thickness (SCT) and choroidal thickness (CT) at 3000 µm temporally, nasally, superiorly, and inferiorly to the fovea were measured. Multiple comparisons were performed between eyes of healthy volunteers and eyes of thalassemic patients divided into three groups depending on the presence of PXE-like changes: 76 eyes without fundus abnormalities, 20 eyes with peau d'orange and 24 eyes with peau d’orange and angioid streaks.
Results:
No significant differences with regard to age, sex, and refractive error were present among groups. Compared to control group (299,74µm), SCT was significantly reduced in thalassemic eyes with normal fundus (256,51µm, p=0.026) and in thalassemic eyes with peau d’orange and angioid streaks (246,79 µm, p=0.040). Thalassemic eyes with only peau d’orange had SCT similar to control group (297,55 µm). Similar pattern of results was obtained superiorly and temporally to the fovea between groups. No significant differences were observed between groups nasally and inferiorly to the fovea.
Conclusions:
Thalassemic patients with normal fundus appearance have thinner choroid than control subjects, however the presence of PXE-like changes affects significantly choroidal thickness. Choroidal thickness increases if peau d’orange is present, however it reduces when angioid streaks develop. This change in the choroid supports the hypothesis that peau d’orange and angioid streaks represent different stages of the disease, similar to PXE. Progressive calcification of the Bruch’s membrane that leads to peau d’orange development in β-thalassemia may induce a temporary inflammatory response and therefore a thickening of choroidal tissue. Angioid streaks, signs of excessive and long-term calcification of the Bruch’s membrane, are associated with increased thinning indicating a potential pathogenetic and prognostic role. Non-invasive choroidal thickness measurement might be an useful tool to monitor disease stages and progression.
Keywords: 452 choroid •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
550 imaging/image analysis: clinical