Abstract
Purpose: :
Despite the development and establishment of state-of-the-art retinal imaging technology, there is a lack of good clinical studies assessing objective changes in patients following an attack of acute primary angle closure (APAC). The aim of this study was to prospectively assess, using different objective imaging parameters, the progression of patients following APAC.
Methods: :
Twenty patients with a single attack of APAC presenting to the Western Eye Hospital in London were prospectively enrolled in this study. Patients were assessed with Heidelberg Retinal Tomography (HRT3), Scanning Laser Ophthalmoscopy (GDx-VCC) and Spectral Domain Optical Coherence Tomography (SD-OCT) as well as Humphrey Visual Field (HVF) repeatedly from within a month of the acute attack to up to eighteen months follow-up. Progression for each imaging modality was assessed with multiple parameters including for HRT (5): rim area, rim volume, mean RNFL thickness, linear cup-to-disc ratio and Glaucoma Probability Score (GPS); for GDX (5): TSNIT, Superior and Inferior Averages, TSNIT Standard Deviation and Nerve Fiber Index (NFI); and for the OCT (2): RNFL thickness profile and retina thickness map. Repeated imaging was performed in all patients.
Results: :
All patients showed changes over time in both RNFL and optic disc assessment. At 18 months, 67% of patients showed progression in 4/5 GDx parameters, and 33% in all 5. HRT analysis similarly showed progression in 4/5 parameters in 70% of patients, and 30% in all 5. OCT showed similar results.
Conclusions: :
This study shows that progressive changes in both HRT and nerve fiber layer analysis occur following APAC. As far as we are aware, this is the first prospective longitudinal study where multiple imaging modalities have been used to provide objective measurements of changes. It confirms that APAC patients need long-term follow-up after the acute attack.
Keywords: imaging/image analysis: clinical • nerve fiber layer • optic nerve