Scheie Visual Field Grading System

Abstract

Purpose : Staging glaucoma patients and monitoring their progression is crucial in managing glaucoma patients effectively; however, no method of grading visual field (VF) defects has been widely accepted throughout the glaucoma community due to numerous limitations of existing grading systems. The Scheie Visual Field Grading System (SVFGS) was created to convey qualitative and quantitative information regarding glaucomatous visual field defects in an objective, reproducible, and easily applicable manner.

Methods : To create the SVFGS, we reviewed literature on different grading systems that classify glaucomatous VF defects based on Standard Automated Perimetry (SAP). Our goal was to create an improved grading system that provided information about hemifield involvement and location of VF defects while also assigning a grade that correlated with the actual clinical severity of glaucomatous damage. To test the reproducibility of the SVFGS, three glaucoma specialists at Scheie Eye Institute were given the same 50 visual fields and asked to grade them using the SVFGS. The graders were timed to measure the ease of use and were asked to individually rank visual fields according to their assessment of the clinical severity of glaucomatous damage. These rankings were compared to the rankings assigned by the calculated SVFGS grade.

Results : The SVFGS categorizes visual fields into groups based on the pattern of visual field depression. Visual fields within each group are then given a grade that incorporates the Humphrey visual field index, location of visual defects for both superior and inferior hemifields, and blind spot involvement. Based on blinded tests, the SVFGS had 100% reproducibility amongst the three glaucoma specialists, with each VF taking less than 30 seconds on average to grade. Also, the calculated SVFGS grade corresponded with the clinical assessment of the glaucomatous damage.

Conclusions : The SVFGS is an easy-to-use, reproducible tool that allows for clinical staging of patients and may be used to monitor and risk-stratify glaucomatous progress in patients longitudinally. The SVFGS makes the visual field a quantitative trait, which can then be associated with genetic variants that correlate with the development or progression of glaucoma in genetic studies. Ultimately, the system may help to standardize visual field grading, to more easily identify specific visual field defects, and to optimize treatment for glaucoma patients.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.