Abstract
Purpose:
To compare angle metrics with spectral domain OCT in phakic and pseudophakic eyes and to investigate their relation with gonioscopy, biometry and Scheimpflug imaging.
Methods:
Phakic and pseudophakic patients from the Glaucoma and Comprehensive clinics of the Doheny Eye Centers were prospectively enrolled. Patients with previous surgical procedures, other than uneventful phacoemulsification, were excluded.<br /> All participants underwent gonioscopy by a glaucoma expert. Optical biometry and Scheimpflug imaging were performed to measure axial length, anterior chamber depth (ACD) and anterior chamber angle (ACA). Spectral domain OCT images of the inferior angle were acquired and Schwalbe’s line angle opening distance (SL-AOD) and SL trabecular iris space area (SL-TISA) were measured with ImageJ.
Results:
The pseudophakic group (68 eyes) had significantly larger ACD (p<0.001), larger ACA (p<0.001), and greater gonioscopic grades (p<0.001) compared with the phakic group (67 eyes), despite the absence of a difference in axial length between the groups (p=0.154).<br /> SL-AOD was 533±310μm in the phakic and 744±227 in the pseudophakic group (p<0.001). Likewise, SL-TISA was larger in the pseudophakic compared to the phakic group (0.268±0.934 versus 0.195±0.126 mm2, p<0.001). There was a moderate positive correlation between SL-AOD/SL-TISA and axial length (r=0.313/0.322), ACD (r=0.459/0.379), gonioscopic grade (r=0.555/0.520) and ACA (r=0.625/0.587) (all p<0.001). In multiple regression analysis, ACA was the most significant parameter that could predict SL-AOD in the model (R2=0.452), while adding ACD and gonioscopy grade in a stepwise approach, increased the model fit to an R2 of 0.625 (all p<0.001).
Conclusions:
Angle metrics are larger in pseudophakic eyes compared to phakic eyes, as measured by spectral domain OCT. Biometry, gonioscopy and Scheimpflug imaging can provide measurements that partially explain the variability in SL-based metrics with OCT.