ABSTRACT
Objective:
To characterize the distribution characteristics of choroidal thickness in healthy normal subjects and to define the diagnostic cut-off value for pachychoroid.
Methods:
A
cross-sectional study design was carried out.Four hundred and forty-six
eyes of 230
healthy subjects from the pachychoroid
disease spectrum (PCD) cohort in
Beijing Tongren
Hospital from April 2018 to June 2021, were enrolled for the choroidal thickness distribution
analysis.Three hundred and fourteen
eyes of 274
patients with PCD including 149
eyes of 113
patients with
central serous chorioretinopathy, 95
eyes of 81
patients with polypoid choroidal vasculopathy, 70
eyes of 60
patients with neovascular
age-related macular degeneration, along with 382
eyes of 199 normal subjects matched for
refractive error, age and
gender with PCD were selected for likelihood ratio
analysis.Routine
eye examinations including the best corrected
visual acuity,
intraocular pressure, slit-lamp
microscopy, dilated fundus examination and
color fundus
photography were performed in all subjects.Swept-source
optical coherence tomography (SS-OCT) of 9 mm×9 mm scanning mode was used to
measure the subfoveal choroidal thickness (SFCT) automatically in nine macular regions according to the Early
Treatment Diabetic Retinopathy Study
classification system using TOPCON Advanced Boundary Segmentation (TABS)
software.Pearson linear correlation
analysis and Spearman rank correlation
analysis were adopted to evaluate the correlations between SFCT and age, diopter.Multiple
linear regression was employed to analyze the factors affecting SFCT.After age and
refractive error adjustment, the
likelihood ratio test was used to determine the diagnostic cut-off value for pachychoroid.This study adhered to the
Declaration of Helsinki.The study protocol was approved by an
Ethics Committee of
Beijing Tongren
Hospital (No.TRECKY2016-054). Written
informed consent was obtained from each subject prior to entering the cohort.
Results:
A negative correlation was found between SFCT and age in normal
eyes ( r=-0.34, P<0.001), in both normal
male and
female subjects ( r=-0.43, P<0.001; r=-0.38; P<0.001). A weak positive correlation was found between SFCT and diopter ( rs=0.19, P<0.001). It was found that age and diopter were strongly correlated with SFCT (both at P<0.001). The cut-off values for pachychoroid in 20-39 years group, 40-59 years group, 60-79 years group and ≥80 years group were 320-330 μm, 330-340 μm, 250-275 μm and 200-225 μm, respectively.The percentages of
eyes with pachychoroid in 20-39 years group, 40-59 years group and ≥60 years group were 14.71%(10/68), 24.48%(47/192) and 28.89%(55/184), respectively, showing statistically significant differences among them ( χ2=6.170, P=0.046; LR=6.579, P=0.037). The proportion of pachychoroid in ≥60 years group was significantly higher than that of 20-39 years group, showing a statistically significant difference ( χ2=5.982, P=0.014; LR=6.479, P=0.011).
Conclusions:
The distribution characteristics of pachychoroid vary in normal subjects over age.Age and diopter are the independent influencing factors of SFCT.