Chang Xi Chen

Subfoveal choroidal thickness: the Beijing Eye Study.

PURPOSE To study subfoveal choroidal thickness (SFCT) in adult Chinese subjects and its correlation with ocular biometric parameters, refractive error, and age. DESIGN Population-based longitudinal study. PARTICIPANTS The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years (range, 50-93 years). METHODS A detailed ophthalmic examination was performed, including spectral-domain optical coherence tomography (SD-OCT) with enhanced depth imaging for measurement of SFCT. MAIN OUTCOME MEASURES Subfoveal choroidal thickness. RESULTS The SFCT measurements were available for 3233 subjects (93.2%). Mean SFCT was 253.8±107.4 μm (range, 8-854 μm). In multivariate analysis, SFCT increased with younger age (P<0.001; correlation coefficient r=4.12; beta coefficient=0.37), shorter axial length (P<0.001; r=44.7; beta coefficient=0.46), male gender (P<0.001; r=28.5; beta coefficient=-0.13), deeper anterior chamber depth (P<0.001; r=39.3; beta coefficient=0.13), thicker lens (P<0.001; r=26.8; beta coefficient=0.08), flatter cornea (P<0.001; r=46.0; beta coefficient=0.11), and better best-corrected visual acuity (BCVA) (logarithm of minimal angle of resolution; P=0.001; r=48.4; beta coefficient=0.06). In multivariate analysis, SFCT was not significantly associated with blood pressure, ocular perfusion pressure, intraocular pressure, cigarette smoking, alcohol consumption, serum concentrations of lipids and glucose, diabetes mellitus, and arterial hypertension. In the myopic refractive error range of more than -1 diopter (D), SFCT decreased by 15 μm (95% confidence interval [CI], 11.9-18.5) for every increase in myopic refractive error of 1 D, or by 32 μm (95% CI, 37.1-26.0) for every increase in axial length of 1 mm. For each year increase in age, the SFCT decreased by 4.1 μm (95% CI, 4.6-3.7) (multivariate analysis). CONCLUSIONS Subfoveal choroidal thickness with a mean of 254±107 μm in elderly subjects with a mean age of 65 years decreased with age (4 μm per year of age) and myopia (15 μm per diopter [D] of myopia). It was also associated with male gender and the ocular biometric parameters of a deeper anterior chamber and thicker lens. The association between SFCT and BCVA indicates a functional aspect of SFCT. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Anterior Chamber Depth and Chamber Angle and Their Associations with Ocular and General Parameters: The Beijing Eye Study

PURPOSE To investigate the normative data of anterior chamber depth (ACD) and angle width and their associations in Chinese adults. DESIGN Population-based study. METHODS The Beijing Eye Study 2006 included 3,251 subjects (73.3%) (aged 45+ years) out of 4,439 subjects who participated in the 2001 survey and who returned for reexamination. The subjects underwent an ophthalmologic examination including measurement of the anterior chamber dimensions by slit-lamp-based optical coherence tomography (OCT). RESULTS Out of the 3,251 subjects, OCT measurements were available for 2,985 subjects (91.8%). Mean ACD measured 2.42 +/- 0.34 mm and the mean anterior chamber angle (ACA) was 38.3 +/- 16.3 degrees. In multivariate analysis, a shallow chamber depth was significantly associated with age (P < .001), hyperopic refractive error (P < .001), female gender (P < .001), short body stature (P = .003), nuclear cataract (P = .03), central corneal thickness [CCT] (P < .001), large optic disk (P < .001), and presence of chronic angle-closure glaucoma (P < .001). Correspondingly, a narrow ACA was associated with age (P < .001), female gender (P < .001), hyperopia (P < .001), nuclear cataract (P < .001), short body stature (P = .001), large optic disk (P < .001), and angle-closure glaucoma (P < .001). Chamber depth and angle width were not associated with presence of age-related maculopathy and diabetic retinopathy. CONCLUSIONS A shallow anterior chamber and a narrow chamber angle in Chinese adults are associated with age, female gender, hyperopia, nuclear cataract, small optic disk, short body stature, CCT, and chronic angle-closure glaucoma. These data may be helpful to explain anatomic relationships of the anterior segment of the eye, and to elucidate risk factors of angle-closure glaucoma.

Subfoveal Choroidal Thickness in Diabetes and Diabetic Retinopathy

PURPOSE To examine subfoveal choroidal thickness (SFCT) in patients with diabetes mellitus and patients with diabetic retinopathy. DESIGN Population-based, cross-sectional study. PARTICIPANTS The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6 ± 9.8 years (range, 50-93 years). METHODS A detailed ophthalmic examination was performed including spectral-domain optical coherence tomography (OCT) with enhanced depth imaging for measurement of SFCT and fundus photography for the assessment of diabetic retinopathy. MAIN OUTCOME MEASURES Subfoveal choroidal thickness. RESULTS Fasting blood samples, fundus photographs, and choroidal OCT images were available for 2041 subjects (58.8%), with 246 subjects (12.1 ± 0.7%) fulfilling the diagnosis of diabetes mellitus and 23 subjects having diabetic retinopathy. Mean SFCT did not differ significantly between patients with diabetes mellitus and nondiabetic subjects (266 ± 108 vs. 261 ± 103 μm; P=0.43) nor between patients with diabetic retinopathy and subjects without retinopathy (249 ± 86 vs. 262 ± 104 μm; P = 0.56). After adjustment for age, sex, axial length, lens thickness, anterior chamber depth, corneal curvature radius, and best-corrected visual acuity, SFCT was associated with a higher glycosylated hemoglobin (HbA1c) value (P<0.001; regression coefficient B, 8.18; 95% confidence interval [CI], 4.02-12.3); standardized coefficient β, 0.08) or with the presence of diabetes mellitus (P = 0.001; B, 21.3; 95% CI, 9.12-33.5) but not with presence of diabetic retinopathy (P = 0.61) or stage of diabetic retinopathy (P = 0.14). As a corollary, after adjusting for age, region of habitation, body mass index, systolic and diastolic blood pressure, and level of education, diabetes mellitus was associated with a thicker SFCT (P<0.001). In contrast, neither presence of diabetic retinopathy (P = 0.61) nor stage of diabetic retinopathy (P = 0.09) were associated significantly with SFCT after adjusting for body mass index, diastolic and systolic blood pressure, and level of education and after adjusting for blood glucose concentrations, HbA1c value, diagnosis of diabetes mellitus, and systolic and diastolic blood pressure, respectively. CONCLUSIONS Patients with diabetes mellitus had a slightly, but statistically significantly, thicker subfoveal choroid, whereas presence and stage of diabetic retinopathy were not associated additionally with an abnormal SFCT. Whereas diabetes mellitus as a systemic disease leads to a slight thickening of the choroid, diabetic retinopathy as an ocular disorder was not associated with choroidal thickness abnormalities after adjusting for the presence of diabetes mellitus. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Reproducibility of subfoveal choroidal thickness measurements with enhanced depth imaging by spectral-domain optical coherence tomography.

PURPOSE To measure the interobserver reproducibility and intra-observer reproducibility of subfoveal choroidal thickness measurements performed by enhanced depth imaging of spectral-domain optical coherence tomography (EDI-OCT) in a population-based setting. METHODS The Beijing Eye Study 2011 was a population-based study performed in rural and urban regions of Greater Beijing. The study included 3468 individuals with a mean age of 64.6 ± 9.8 years (range, 50-93 years). The participants underwent EDI-OCT and the subfoveal choroidal thickness (SFCT) was measured. To examine the interobserver variability, all images were assessed by two examiners independently of each other within 2 months. To examine the intra-observer reproducibility, a smaller study sample consisting of 21 eyes of 21 healthy subjects from the Tongren Eye Center was included in the study. These latter subjects were scanned 10 times with 1 minute breaks between each examination. The SFCT was measured by the same observer within 2 weeks. The intrasession within subject SD, the coefficient of variation, and the intraclass correlation coefficient (ICC) were calculated. RESULTS EDI-OCTs were performed for 3233 subjects. Mean SFCT measured by grader one and grader two were 254.6 ± 107.3 μm and 253.8 ± 107.4 μm, respectively, with a mean difference of 3.14 ± 13.1 μm (95% confidence interval, 0.0, 24.0). Bland-Altman plot showed 1.9% (61/3233) points outside the 95% limits of agreement. For the assessment of the intra-observer reproducibility, the ICC was 1.00 (P < 0.001, and the mean coefficient of variation was 0.85% ± 1.48%). CONCLUSIONS Under routine examination conditions, SFCT measurements by EDI-OCT showed a high intra-observer reproducibility and interobserver reproducibility.

Visual Acuity and Subfoveal Choroidal Thickness: The Beijing Eye Study

PURPOSE To examine the association between best corrected visual acuity (BCVA) and subfoveal choroidal thickness. DESIGN Population-based study. METHODS The Beijing Eye Study 2011 included 3468 subjects with ages of 50+ years. The participants underwent an ophthalmologic examination including spectral-domain optical coherence tomography with enhanced depth imaging for measurement of choroidal thickness. BCVA was measured as logarithm of the minimal angle of resolution. RESULTS Of the 3468 participants, choroidal measurements were available for 3233 (93.2%) subjects. In multivariate analysis, better BCVA was significantly associated with thicker subfoveal choroid (P < 0.001) in general and a subfoveal choroid thicker than 30 μm (P < 0.001) in particular, after adjusting for younger age (P < 0.001), higher level of education (P < 0.001), taller body stature (P < 0.001), higher body mass index (P = 0.005), absence of glaucoma (P = 0.001), absence of diabetic retinopathy (P < 0.001), absence of late-stage age-related macular degeneration (P < 0.001), and axial length shorter than 26.0 mm (P < 0.001) (correlation coefficient r:0.56). If eyes with glaucoma, diabetic retinopathy, late-stage age-related macular degeneration or myopic retinopathy were excluded, better BCVA was still significantly associated with thicker subfoveal choroid (P < 0.001) and subfoveal choroid thicker than 30 μm (P < 0.001) in multivariate analysis. In a reverse manner, thicker subfoveal choroid was associated with better BCVA (P < 0.001) after adjusting for younger age (P < 0.001), male gender (P < 0.001), longer axial length (P < 0.001), and higher corneal curvature radius (P < 0.001). CONCLUSIONS Better visual acuity is strongly associated with thicker subfoveal choroid independent of additional factors, such as age, axial length, education level, and major ocular diseases.

Prevalence and associations of incomplete posterior vitreous detachment in adult Chinese: the Beijing Eye Study.

Purpose To determine prevalence and associations of incomplete posterior vitreous detachment (PVD). Methods The population-based cross-sectional Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years (range: 50–93 years). A detailed ophthalmic examination was performed including spectral-domain optical coherence tomography (SD-OCT). Incomplete PVD was differentiated into type 1 (shallow PVD with circular perifoveal vitreous attachment), type 2 (PVD reaching fovea but not foveola), type 3 (shallow PVD with pinpoint vitreous attachment at the foveola), and type 4 (PVD completely detached from the macula, attached to the optic disc). Results An incomplete PVD was detected in 3948 eyes (prevalence: 60.5±0.6%; 95% Confidence Interval (CI): 59.3%,61.7%) of 2198 subjects (67.1±0.8%;95%CI: 65.6%,68.7%). Type 1 PVD was seen in 3090 (78.3%) eyes, type 2 PVD in 504 (12.8%) eyes, type 3 PVD in 70 (1.8%) eyes, and type 4 PVD in 284 (7.2%) eyes. Prevalence of incomplete PVD was associated with younger age (P<0.001;OR:0.91), male gender (P<0.001;OR:0.64), rural region of habitation (P<0.001;OR:0.49), larger corneal diameter (P = 0.04;OR:0.91), better best corrected visual acuity (P = 0.02;OR:0.41), and hyperopic refractive error (P<0.001;OR:1.15). The type of incomplete PVD was associated with higher age (P<0.001), urban region of habitation (P<0.001), myopic refractive error (P = 0.001), thinner cornea (P = 0.005), and better best corrected visual acuity (P = 0.056). Conclusions In adult Chinese in Greater Beijing, prevalence of an incomplete PVD (detected in 67.1% subjects) was associated with younger age, male gender, rural region of habitation, larger corneal diameter, better best corrected visual acuity and hyperopic refractive error.

Subfoveal Choroidal Thickness in Retinal Vein Occlusion

1. Boyer DS, Faber D, Gupta Set al; ; Ozurdex CHAMPLAIN Study Group. 2. Dexamethasone intravitreal implant for treatment of diabetic macular edema in vitrectomized patients. Retina 2011;31:915–23. 2. Meyer LM, Schönfeld CL. Cystoid macular edema after complicated cataract surgery resolved by an intravitreal dexamethasone 0.7-mg implant. Case Rep Ophthalmol 2011;2:319–22. 3. Srour M, Querques G, Leveziel N, et al. Intravitreal dexamethasone implant (Ozurdex) for macular edema secondary to retinitis pigmentosa. Graefes Arch Clin Exp Ophthalmol 2013;251: 1501–6. 4. Kim JT, Yoon YH, Lee DH, et al. Dexamethasone intravitreal implant in the silicone oil-filled eye for the treatment for recurrent macular oedema associated with ankylosing spondylitis: a case report. Acta Ophthalmol 2013;91:331–2. 5. Spitzer MS, Kaczmarek RT, Yoeruek E, et al. The distribution, release kinetics, and biocompatibility of triamcinolone injected and dispersed in silicone oil. Invest Ophthalmol Vis Sci 2009;50:2337–43.

Polypoidal Choroidal Vasculopathy in Adult Chinese: The Beijing Eye Study

Figure 1. Optical coherence tomographic image (upper panel) and fundus photograph (lower panel) of an eye with polypoidal choroidal Polypoidal choroidal vasculopathy (PCV) is a choroidal vascular abnormality characterized by macular choroidal neovascularization, orange retinal lesions, subretinal and intraretinal hemorrhage and edema, and sudden and painless visual loss. Because populationbased data on the prevalence and risk factors for PCV have yet to be defined, we conducted the present investigation to assess the prevalence and associations of PCV in a general population. The Beijing Eye Study 2011 is a population-based study in Northern China. The study protocol was approved by the Medical Ethics Committee of the Tongren Hospital and all study participants gave informed consent. Out of 4403 eligible individuals with 50 years old, 3468 subjects (78.8%) participated in the eye examination. The study design included an ophthalmic examination with digital photography of the macula and spectral-domain optical coherence tomography (OCT) of the macula (Spectralis, Heidelberg Engineering, Heidelberg, Germany). We defined PCV as an elevated orange-red lesion on the fundus photographs, characterized by a double-layer sign and high dome-shaped pigment epithelial detachments on the OCT images (Fig 1). The OCT images and fundus photographs were examined repeatedly in several steps, including an assessment by a panel (Y.L., Q.S.Y., W.B.W., J.B.J.). Polypoidal choroidal vasculopathy was diagnosed in 18 eyes (prevalence rate, 0.3 0.1%; 95% CI, 0.1%e0.4%) of 17 subjects (0.5%; 10 men; prevalence rate, 0.5 0.1%; 95% CI, 0.3%e0.7%). Polypoidal choroidal vasculopathy was located in the foveal region in 15 eyes (83%) and was associated with subretinal exudations in 16 (89%). Two eyes showed subretinal scar formation. In all but 1 patient with PCV, the disease occurred unilaterally. Mean age of the subjects with PCV was 74.5 7.5 years (range, 59e87), and mean refractive error was 0.02 1.42 diopters (range, 3.00 to þ2.63). Mean best-corrected visual acuity was 0.31 0.42 logarithm of the minimum angle of resolution (0.65 0.34 Snellen), with 2 eyes having an acuity of 1/20 and altogether 4 eyes having an acuity of <20/60. Polypoidal choroidal vasculopathy was asymptomatic in 10 eyes with a best-corrected visual acuity of 0.10 logarithm of the minimum angle of resolution ( 0.80 Snellen acuity). The eyes with PCV, compared with the contralateral unaffected eyes, did not differ significantly in refractive error (P 1⁄4 0.59), axial length (P 1⁄4 0.48), or intraocular pressure (P 1⁄4 0.97). If only patients with a foveal location of PCV were included in the analysis, subfoveal choroidal thickness was significantly thicker in the affected eyes than in the contralateral eyes (275 90 vs 210 92 mm; P 1⁄4 0.02). The prevalence of PCV increased significantly with age from 0% among those 50 to 54 years old, to 1/643 (0.2%) among those 55 to 59 years old, to 1/508 (0.2%) among those 60 to 64 years old, to 1/469 (2.1%) among those 65 to 69 years old, to 5/540 (1.3%) among those 70 to 74 years old, 5/385 (1.3%) among those 75 to 79 years old, and to 4/260 (1.5%) among those 80 years old. Model building for the multivariate analysis began with all significant factors from the univariate associations (Table 1; available at www.aaojournal.org). From this full model, nonsignificant parameters were removed in a stepwise manner, starting with the parameters with the highest P values. In the final model, presence of PCVwas significantly associated with older age, thicker subfoveal choroid, and thicker central corneal thickness (Table 2; available at www.aaojournal.org). If only patients with a foveal location of PCVwere included, similar results were obtained. The association between PCV and a thicker subfoveal choroid confirms previous hospital-based studies. As in other studies, PCV was strongly associated with older age. In contrast with a Japanese study with a predominance of men, our study did not show a significant association of PCV with gender. In contrast with previous hospital-based studies with a percentage of 14% to 32% of bilaterality of PCV, only 1 of 17 patients in our study (6%) showed bilateral PCV. The observation of a thicker subfoveal choroid in eyes with PCV compared with eyes with exudative age-related macular degeneration may imply that this morphologic difference between the diseases may be a surrogate for differences in the pathophysiology and may explain differences in treatment outcomes observed with PCV as opposed to exudative age-related macular degeneration. In 10 eyes (56%), PCV was asymptomatic, suggesting that it may be more prevalent than hospital-based investigations suggest. Our study has limitations. First, the diagnosis of PCV was based on fundus photographs and OCT images, rather than on indocyanine green angiography, which is the gold standard for PCV

Peripapillary intrachoroidal cavitations. The Beijing eye study.

Purpose To assess prevalence, size and location of peripapillary intrachoroidal cavitations (PICCs) and their associations in a population-based sample. . Methods The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years (range:50-93 years). A detailed ophthalmic examination included enhanced depth imaging of the choroid by spectral-domain optical coherence tomography and fundus photography. PICCs were defined as triangular thickening of the choroid with the base at the optic disc border and a distance between Bruch´s membrane and sclera of ≥200μm. Parapapillary large choroidal vessels were excluded. Results Out of 94 subjects with high myopia (refractive error <-6.0 diopters or axial length >26.5mm in right eyes), OCT images were available for 89 (94.7%) participants. A PICC was detected in 15 out of these 89 highly myopic subjects (prevalence:16.9±4.0%) and in none of hyperopic, emmetropic or medium myopic subgroups each consisting of 100 randomly selected subjects. Mean PICC width was 4.2±2.3 hours (30°) of disc circumference and mean length was 1363±384μm. PICCs were located most frequently (40%) at the inferior disc border. On fundus photos, a typical yellow-orange lesion was found in 8 (53%) eyes with PICCs. In binary regression analysis, presence of PICCs was significantly associated with optic disc tilting (P=0.04) and presence of posterior staphylomata (P=0.046). Conclusions Prevalence of PICCs in the adult Chinese population was 16.9±4.0% in the highly myopic group, with no PICCs detected in non-highly myopic eyes. PICCs were located most frequently at the inferior optic disc border. Only half of the PICCs detected on OCT images showed a yellow-orange lesion on fundus photos. Presence of PICC was significantly associated only with an increased optic disc tilting and presence of posterior staphylomata, while it was not associated with axial length, refractive error or other ocular or systemic parameters.

Horizontal and vertical optic disc rotation. The Beijing Eye Study

Purpose To measure the optic disc rotation around the vertical and horizontal disc axis and to evaluate associations with general and ocular parameters. Design Population-based study Methods In the Beijing Eye Study, 3468 participants (mean age:64.6±9.8 years; range:50–93 years) underwent an ophthalmological examination which included spectral-domain optical coherence tomography (OCT) with enhanced depth imaging. Using the OCT images, we determined the amount of the rotation of the optic disc (defined as Bruch´s membrane opening (BMO)) around the vertical axis and horizontal axis. Results Optic disc rotation measurements were available for 3037 (87.6%) individuals. In multivariate analysis, larger optic disc rotation around the vertical axis (range:-4.90° to 41.0°) was associated (regression coefficient r:0.27) with high axial myopia (axial length ≥26.5 mm) (P<0.001;standardized regression coefficient beta beta:0.09), longer disc-fovea distance (P = 0.001;beta:0.09) and wider parapapillary beta/gamma zone (P<0.001;beta0.12). Larger optic disc rotation around the horizontal axis (range:-7.10° to 26.4°) was associated (r:0.32) with high axial myopia (P = 0.001;beta:0.08), larger optic disc-fovea angle (P<0.001;beta:0.13), thinner superior nasal retinal nerve fiber layer (RNFL) thickness (P<0.001;beta:-0.19) and thicker inferior nasal RNFL thickness (P<0.001;beta:0.17). Conclusions Vertical optic disc rotation was associated with highly myopic axial elongation, increased disc-fovea distance and development or enlargement of parapapillary, Bruch´s membrane free, gamma zone, while macular Bruch´s membrane length is not affected. Horizontal optic disc rotation was associated with inferior dislocation of the fovea, in addition to a thinner superior nasal RNFL and thicker inferior nasal RNFL. The latter association may be taken into account in the interpretation of RNFL thickness profiles.