RESUMO
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.
RESUMO
Objective:To investigate the repeatability and correlation in tilt and decentration measurement of crystalline lens and intraocular lens (IOL) under non-mydriatic and mydriatic conditions using swept-source ocular coherence tomography CASIA2.Methods:A diagnostic test study was conducted.A total of 109 cataract patients (157 eyes) who received phacoemulsification with IOL implantation surgery in the Affiliated Hospital of North Sichuan Medical College from March to July 2020 were enrolled.The decentration and tilt of crystalline lens and IOL under non-mydriatic and mydriatic conditions were measured for three times by a single examiner using CASIA2 before and one week after surgery.The 0.5% compound tropicamide eye drops were used to dilate.Repeatability was evaluated by within-standard deviation, test-retest repeatability (TRT), coefficient of variation (CoV) and intraclass correlation coefficient (ICC). The correlation in decentration and tilt of crystalline lens and IOL between before and after mydriasis was assessed by Pearson correlation coefficient.This study adhered to the Declaration of Helsinki, and the study protocol was approved by an Ethics Committee of the Affiliated Hospital of North Sichuan Medical College (No.2020ER030-1). Written informed consent was obtained from all subjects before any medical examination.Results:The decentration of crystalline lens under non-mydriatic and mydriatic conditions was (0.217±0.112)mm and (0.220±0.110)mm, respectively, and the tilt was (5.017±1.422)° and (5.310±1.645)°, respectively.The decentration of IOL under non-mydriatic and mydriatic conditions was (0.245±0.136)mm and (0.250±0.145)mm, respectively, and the tilt was (5.144±1.345)° and (5.437±1.646)°, respectively.No significant difference was found between non-mydriatic and mydriatic conditions (all at P>0.05). Under both non-mydriatic and mydriatic conditions, the crystalline lenses of both eyes decentered and tilted toward the inferotemporal direction, and the IOL of right eyes decentered toward the inferior and tilted toward the inferotemporal direction, and the IOL of left eyes decentered and tilted toward the inferotemporal direction.Except the crystalline lens decentration, the measurement repeatability of crystalline lens tilt, IOL decentration and tilt in cataract patients before and after mydriasis was good, with ICC range in 0.815-0.984, TRT<50% and CoV≤14.840%.The measurement repeatability of crystalline lens decentration was poor, and the measurement repeatability of decentration axis, tilt and tilt axis of crystalline lens, and the repeatability of decentration and tilt of IOL were good in both eyes, with ICC range in 0.757-0.998, TRT<50% and CoV≤17.763%.There were good correlations in decentration, decentration axis, tilt and tilt axis of crystalline lens and IOL between non-mydriatic and mydriatic conditions (all r≥0.679, all at P<0.01). Conclusions:The measurement repeatability of decentration axis, tilt and tilt axis of crystalline lens and IOL, as well as the decentration of IOL by CASIA2 before and after mydriasis is good.The correlations of the measured parameters before and after mydriasis are good.