Ability of Spectral-Domain Optical Coherence Tomography to Predict Humphrey Visual Field Defects in Patients With Open-Angle Glaucoma
Narrative Responses:
Purpose
To investigate the ability of clock hour measurements of neuro-retinal rim (NRR) thickness and retinal nerve fiber layer (RNFL) thickness using Cirrus HD Spectral-Domain Optical Coherence Tomography (OCT) to predict the pattern of corresponding humphrey visual field (HVF) defects in patients with open-angle glaucoma.
Methods
Retrospective, single-center chart review of patients with open-angle glaucoma who had both an optic nerve head (ONH) analysis measured by Cirrus HD SD-OCT and a HVF within 3 months between September 2011 and March 2013. A total of 33 eyes of 26 patients were included, as well as 30 control eyes. Glaucomatous visual field defects were defined by a standard criteria, confirmed by a minimum of two reliable tests (false positives <15%, FN <15%, fixation loss <20%), and categorized into three groups: superior field defects only (n=18), inferior field defects only (n=6), and miscellaneous (n=9) field defects.
Results
Patients with superior visual field defects had statistically significant NRR thinning at all clock hours vs. controls (p<0.0001 for all clock hours). Patients in the inferior visual field defects group had significant NRR thinning compared to controls from clock hours 11 to 1 (p= 0.02, 0.03, and 0.04 respectively) and clock hours 6 and 7 (p=0.03 for both). Neither group showed preferential localized thinning at the clock hours of the corresponding visual field regions as designated by structure/function correlation maps (‘Garway-Heath Map’) compared to non-corresponding areas.
Conclusion
Previous studies have shown that clock-hour neuro-retinal rim assessment using Cirrus HD-OCT may enhance glaucoma diagnostic ability. However, while NRR clock-hour measurements are helpful in predicting whether or not a glaucoma patient will have a visual field defect, they do not appear to reliably predict the type of defect.