Five-year changes in anterior segment parameters in an older population in urban southern China: the Liwan Eye Study

Abstract

PurposeTo investigate the 5-year changes in static and dynamic anterior segment optical coherence tomography (AS-OCT) parameters and their predictors.MethodsThis was a prospective, population-based cohort study of people aged 50 years and older residing in the Liwan District, Guangzhou, China. Standardised AS-OCT scans were performed in November 2008 and November 2013 under dark and light conditions. Customised software was used to analyse horizontal AS-OCT images. Parameters in dark and measurements of light-to-dark changes were used for analyses.ResultsA total of 186 (71.8%) subjects underwent AS-OCT twice, 5 years apart and were included for analyses. The mean age in 2008 was 64.7±7.0 years, and 60.2% were women. The anterior chamber width (ACW) decreased from 11.74±0.44 mm in 2008 to 11.60±0.37 mm in 2013 (p=0.001). There was a trend towards a decrease in dynamic capacity (light-to-dark changes) in the anterior segment, with decreased iris thickness at 750 µm (ΔIT750), ΔACW, Δ anterior chamber area (ACA) and Δ pupil diameter at 5 years (all p<0.05). After adjusting for age and sex, the following baseline parameters were associated with a greater decrease rate in trabecular iris space area at 500 µm (TISA500) at 5 years: TISA500, IT750 and ACA in dark (p<0.001 for all).ConclusionsAnterior chamber angle width decreased and the amount of light-to-dark changes declined during 5-year follow-up. Subjects with greater height, wider angle width and thicker iris at baseline have greater angle narrowing at follow-up.

Iris volume change with physiologic mydriasis to identify development of angle closure: the Zhongshan Angle Closure Prevention Trial

“…Change in angle parameters and in their dynamic change with pupil size is related to subject age. 10 There is now considerable evidence that the dynamic behavior of the iris and choroid are contributing features to PACD. [11][12][13] In all eyes, the iris loses volume by aqueous humor transfer from the iris stroma to the anterior chamber immediately upon pupil dilation.…”

Intradevice Repeatability and Interdevice Agreement of Ocular Biometric Measurements: A Comparison of Two Swept-Source Anterior Segment OCT Devices

“…[6][7][8][9][10][11] Second, these measurements could be used to track longitudinal progression of angle narrowing or response to treatments for angle closure, such as laser peripheral iridotomy (LPI). [12][13][14][15] Finally, the recent landmark Zhongshan Angle Closure Prevention trial demonstrated that the current definition of primary angle closure suspect, which comprises the vast majority for PACD, may be too broad to guide treatment with LPI. 16 Therefore, AS-OCT measurements, which reflect anatomic and physiologic changes related to angle closure, could complement gonioscopy to refine the management of early stage PACD.…”

Ocular Biometry of Primary Angle-Closure Disease in Younger Patients

“…We found that the AL, LT, IT, TCA, and CBT were positively associated with age, while the LV and SFCT were negatively correlated with age. There has been no systematic study that analyzed the relationship between ocular biometric parameters and age in PACD patients, but previous studies of normal populations have shown that the AL,TCA,CBT, and SFCT were negatively correlated with age (12,16,26,27,(30)(31)(32)(33), while the LT, LV, and IT were positively associated with age (12,23). The correlations between age and LT, IT, and SFCT in this study were consistent with those in normal people, but the correlations between age and AL, LV, CBT, and TCA were opposite to those in the normal population.…”