Evaluation of Nasal and Temporal Anterior Chamber Angle with Four Different Techniques

Background: Anterior chamber angle (ACA) can be measured by many different techniques. In order for a technique to be a part of the routine eye examination, it has to be quick and easy in good agreement with gonioscopy both nasally and temporally. Aim: To investigate variation in ACA measurement between gonioscopy, van Herick technique, anterior segment optical coherence tomography (AS-OCT) and Sirius Scheimpflug-Camera both nasally and temporally. Method: The ACA of 50 eyes of 25 healthy subjects was measured with gonioscopy, van Herick technique, AS-OCT and Sirius Scheimpflug-Camera. The angle was measured both nasally and temporally. Results: No statistically significant difference could be found between gonioscopy, van Herick technique and AS-OCT either nasally or temporally. The Sirius Scheimpflug-Camera on the other hand showed statistically significant difference to gonioscopy (p < 0.0001), van Herick technique (p < 0.0001) and AS-OCT (p < 0.0001) both nasally (p = 0.03, p = 0.001, p < 0.0001) and temporally (p = 0.0002, p = 0.001, p < 0.0001). Conclusion: This study showed good agreement between three of the four techniques. ACA measurements obtained by the Sirius Scheimpflug-Camera should therefore not be considered interchangeable with those obtained by the remaining three methods.