Association between axial length and choroidal thickness in early age-related macular degeneration

The clinical course of age-related macular degeneration (AMD) is related to choroidal conditions, and can be determined by the evaluation of the central choroidal thickness (CCT). The aim of this study was to determine the association between the axial length (AL) and choroidal thickness in AMD by measuring these parameters in patients with and without AMD. Seventy eyes of 70 patients (34 men and 36 women; age, 64-88 years; mean age, 77.0 ± 6.5 years) who underwent cataract surgery from February 2015 to March 2020 at the Department of Ophthalmology, Keio University School of Medicine were retrospectively analyzed. The AMD group (29 patients, 29 eyes) included eyes with early AMD, whereas the control group (41 patients, 41 eyes) included those without ocular diseases other than cataract. Optical coherence tomography images were used to measure the CCT and the choroidal vessel diameter (CVD). The IOL Master was used to measure the AL. The results revealed that mean CCT was greater in the AMD group (238.3 ± 108.3 μm) compared with the age-matched control group (187.2 ± 66.8 μm) (p = 0.03). The CCT was negatively correlated with AL in the overall sample (r = -0.42, p = 0.001), the AMD group (r = -0.42, p = 0.02), and the control group (r = -0.42, p = 0.006). Note that all eyes with CCT > 350 μm were included in the AMD group. CCT and CVD were positively correlated in the overall sample (r = 0.76, p < 0.001) as well as in the individual groups (AMD: r = 0.82, p < 0.001; control: r = 0.76, p = 0.004). Given that CCT is an important parameter for predicting the prognosis of subfoveal diseases, routine evaluation of AL may be valuable for a better understanding of the pathogenesis of AMD.