Retinal Microvascular Alterations and Choroidal Changes in Cystic Fibrosis Before and After CFTR Modulator Therapy

To evaluate alterations in the retinal microvasculature, choroid, and choriocapillaris in adults with cystic fibrosis (CF) using optical coherence tomography angiography (OCTA) and swept-source optical coherence tomography, as well as to evaluate longitudinal changes following cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy.

This prospective study included 34 adults with CF and 34 age- and sex-matched controls. Retinal OCTA parameters of the superficial (SVP) and deep vascular plexuses (DVP), choroidal thickness (CT), and choriocapillaris flow-void characteristics were analyzed. Patients with CF underwent repeat imaging after 12-18 months of CFTR modulator therapy.

Compared with controls, patients with CF demonstrated significantly larger foveal avascular zone (FAZ) area and higher SVP vessel density (VD). After adjustment for axial length, FAZ area remained significantly larger in the SVP (0.457 vs. 0.379 mm², p<0.001) and DVP (0.558 vs. 0.442 mm², p<0.001). DVP vessel density showed a significant Group × AL interaction (p=0.039), with higher adjusted marginal means in CF (35.03% vs. 31.55%). DVP total branch length (86.45 vs. 104.08, p=0.007) and skeleton density (2.402 vs. 2.891, p=0.007) were significantly lower in CF. No significant longitudinal changes were observed in retinal OCTA parameters. In contrast, mean CT decreased from a median of 379.6 to 328.8 μm (p<0.001), accompanied by reductions in choriocapillaris flow-void area (p=0.033) and mean flow-void size (p=0.009).

Adults with CF exhibit a retinal microvascular phenotype characterized by enlarged FAZ in both SVP and DVP, increased VD in SVP, and reduced DVP complexity. CFTR modulator therapy was associated with significant choroidal and choriocapillaris changes but not retinal OCTA alterations, suggesting differential responses of retinal and choroidal vascular compartments to treatment.