Clinical and Anterior Segment Anatomical Features in Primary Angle Closure Subgroups Based on Configurations of Iris Root Insertion

Abstract

PurposeTo compare the clinical and anterior segment anatomical features in primary angle closure sub-groups based on configurations of iris root insertion.MethodsPrimary angle closure patients were imaged using anterior segment optical coherence tomography. Anterior chamber depth, iris curvature, iris thickness (IT) at the scleral spur and 500, 750, and 1,500 µm from the scleral spur (IT0, IT500, IT750, and IT1500), lens vault, iris area, angle opening distance (AOD500), angle recess area (ARA750), and trabecular iris space area (TISA750) were measured. Iris root insertion was categorized into a non-basal insertion group (NBG) and basal insertion group (BG).ResultsIn total, 43 eyes of 39 participants belonged to the NBG and 89 eyes of 53 participants to the BG. The mean age of participants was greater in the NBG than the BG (62.7 ± 5.7 vs. 59.8 ± 7.3 years, p = 0.043), and the baseline intraocular pressure was higher in the BG than the NBG (16.4 ± 4.4 vs. 14.9 ± 3.3 mmHg, p = 0.037). The BG showed a greater IT0 (0.265 ± 0.04 vs. 0.214 ± 0.03 mm, p < 0.001) and iris area (1.59 ± 0.24 vs. 1.52 ± 0.27 mm2, p = 0.045), lower ARA750 (0.112 ± 0.08 vs. 0.154 ± 0.08 mm2, p = 0.017) and AOD500 (0.165 ± 0.07 vs. 0.202 ± 0.08 mm, p = 0.014) compared to the NBG.ConclusionsThe BG had a narrower anterior chamber angle, thicker peripheral iris, and higher pretreatment intraocular pressure.

Effects of Choroidal Thickness on Refractive Outcome Following Cataract Surgery in Primary Angle Closure

“…LV was defined as the perpendicular distance between the anterior pole of the crystalline lens and the horizontal line joining the two scleral spurs. AOD 500 was defined as the linear distance between the point of the inner corneoscleral wall (500 µm anterior to the scleral spur) and the iris [ 19 20 ].…”

Glaucoma Progression After Lens Extraction in Primary Angle-closure Glaucoma According to Angle-closure Mechanism

“…6,36 However, because many previous studies have already defined PIC using AS-OCT images, we believe our classification is appropriate. [3][4][5][7][8][9] In conclusion, eyes with PACD may progress after LE, and patients in the PIC group were better protected against glaucomatous progression. In addition, greater glaucoma severity was associated with glaucoma progression, which may be considered when PACD eyes were followed after LE.…”

Association of peripheral anterior synechiae with anterior segment parameters in eyes with primary angle closure glaucoma

“…Our data are in line with previous work from Gazzard et al which showed increased risk of PAS formation in Asian eyes that have shallower anterior chambers as a result of thicker and more anteriorly-placed lenses (ARVO abstract) 21 . Whilst a shallow anterior chamber is the cardinal risk factor for angle closure, several studies have also illustrated that characteristics of the iris, such as peripheral iris thickness also contribute to iridotrabecular contact in angle closure eyes 9 , 22 , 23 . However, in our data, quantitative iris parameters as determined from ASOCT including iris thickness and area, did not correlate with the presence of PAS in PACG eyes.…”

“…More PAS can lead to a greater reduction in aqueous outflow, and hence higher IOP and in turn more significant visual field losses. The presence of a significant amount of PAS and a higher presenting IOP have been suggested to be predictors of the severity of visual field damage, inadequate IOP control post-LPI, and the need of subsequent surgical interventions 23 – 27 .…”