Ocular biometric parameters variation between closed and opened angles in Thai population

Abstract

Purpose : To compare the ocular biometric parameters between closed angle and opened angle by using anterior segment OCT

Methods : This was a cross sectional descriptive study. We enrolled normal, glaucoma suspected and glaucoma participants with visual acuity better than 20/70, refraction ± 6 diopters and astigmatism ± 3 diopters and excluded secondary causes of glaucoma. All consented participants were completely performed eye examination and measured the following ocular biometric parameters including, axial length, central corneal thickness, gonioscopy and Visante®anterior segment optical coherence tomography. Linear regression model was used to test the differences between groups.

Results : Two-hundred twenty three opened angle eyes (112 participants) and 50 closed angle eyes (25 participants) were recruited. The mean age of closed group was significant older than opened group, 63.58 ± 9.06 versus 56.75 ± 13.39 years (p=0.022). Refraction between 2 groups were similar; however, the axial length were significant longer in the opened group; 23.49 ± 0.93 mm versus 22.56 ± 0.92 mm (p<0.05). Intraocular pressure and central corneal thickness were eqivalence. All anterior segment parameters in both nasal and temporal sided of opened group were higher including; anterior chamber depth (ACD) 2.92 ± 0.56mm versus 2.41 ± 0.73mm, p<0.001; temporal angle opening distance 500 μm (AOD500) 0.78 ± 0.33 mm versus 0.5 ± 0.19 mm, p<0.001; nasal AOD500 0.64 ± 0.23mm versus 0.42 ± 0.15 mm, p<0.001; temporal AOD750 0.97 ± 0.36 mm versus 0.67 ± 0.25mm, p<0.001; nasal AOD750 0.81 ± 0.25 mm versus 0.54 ± 0.16mm, p<0.001; temporal trabecular–iris space area 500 μm(TISA500) 0.31 ± 0.15mm² versus 0.19 ± 0.08mm², p<0.001; nasal TISA500 0.24 ± 0.1mm² versus 0.16 ± 0.06mm², p<0.001; temporal TISA750 0.53 ± 0.23mm² versus 0.34 ± 0.13mm², p<0.001; nasal TISA750 0.42 ± 0.15mm² versus 0.27 ± 0.09mm², p<0.001; temporal scleral spur angle 54.39 ± 10.52 degree versus 43.35 ± 10.97 degree, p<0.001; nasal scleral spur angle 49.34 ± 10.25 degree versus 38.06 ± 9.4 degree, p<0.001.

Conclusions : Our study provided anterior segment parameters of opened and closed angle in Thai population which can consider as the normative reference.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.