Abstract
Purpose:
To identify the importance of gonioscopy to properly diagnose angle closure glaucoma (ACG) versus primary open angle glaucoma (POAG). Surveys have demonstrated that approximately 20% of general ophthalmologists perform gonioscopy on glaucoma suspects per year. An additional 20% reported performing gonioscopy less frequently than every 3 years, 40% perform gonioscopy at 1-3 year intervals, and 20% only perform gonioscopy on patients with anatomically narrow angles. We have noted an increase in the diagnosis of occludable anatomically narrow angles (ANA) and angle closure glaucoma (ACG) associated with increased training in gonioscopy.
Methods:
A retrospective study case series examining the electronic medical records of patients diagnosed with occludable angles or ACG previously diagnosed as having POAG since July 2014 were reviewed. 22 patients met inclusion criterion. The majority are female (64%) and hyperopic (50%). 64% of patients were African American patients, 27% Hispanic, 5% Caucasian, and 5% Asian. Any patient with NS 3+ or greater cataract, or evidence of pseudoexfoliation, was excluded from this study. One fellowship trained glaucoma specialist used the same gonioscopy technique for each patient. Specifically patients underwent slit lamp examination in a dark room with all ambient light eliminated. Sussman 4-mirror gonioscopy lens with a 1 mm beam was used to examine each patient’s angles and ZEISS anterior segment optical coherence tomography was performed at the time of diagnosis to confirm the direct gonioscopy findings.
Results:
18% of patients were previously diagnosed as POAG, 41% were previously diagnosed as POAG Suspects, and 32% had no previous associated glaucoma diagnosis. Of the 22 patients, 27% were diagnosed with occludable angles and 68% were diagnosed with ACG.
Conclusions:
Based on the data presented, there seems to be an increased incidence of angle closure glaucoma and anatomically narrow angles post rigorous training in the proper technique of indirect gonioscopy. This may result in the incidence of occludable angles and angle closure glaucoma being underestimated. Further study will be undertaken to better approximate the incidence of occludable angles in order to better determine the predominating risk factors for missing the diagnosis.