Purpose:
The FD-ASOCT is designed to measure anterior segment anatomy. Having a reproducible point of reference from which to take measurements is essential in using this devices for clinical trials. The scleral spur is typically this point of reference. The purpose of this study is to evaluate interobserver agreement in locating the scleral spur (SS) in AS-OCT 2D images obtained using the Swept Source FD-ASOCT(Casia SS-1000, Tomey , Nagoya, Japan)
Methods:
17 patients with a preselected variety of angle anatomy were recruited. After signing an informed consent patients had an eye exam, gonioscopy, and AS-OCT images taken on both eyes. Two observers, one glaucoma specialist and one non clinician, rated images for one eye for quality and then marked the SS locations. Precision was evaluated by percent of readings within 80,100 and 150um of each other.
Results:
see table below. Each data cell represents percentage of images in agreement between 2 observers at the specified threshold. 34 images were evaluated, half at superior-inferior axis and half at nasal-temporal axis. Typically the superior angle is the most difficult to image and evaluate.
Conclusions:
The agreement between observers in locating SS was excellent. The SS can be reproducibly located for use as a landmark in measuring angle anatomy using the Swept Source FD-ASOCT.
Keywords: anterior chamber • imaging/image analysis: clinical • anterior segment