A Novel Scale for Describing Visual Outcomes in Patients Following Resection of Lesions Affecting the Optic Apparatus-unified Visual Function Scale

Introduction: Historically, description of patient visual acuity and visual field changes following intracranial procedures has been very rudimentary. Clinicians and researchers have relied on the use of basic descriptions such as “improved,” “worsened,” and “unchanged” to describe outcomes following resections of tumors affecting the optic apparatus. These descriptors are vague, difficult to quantify, and are challenging to apply in a clinical perspective. Several groups have attempted to combine visual acuity and visual fields into a single assessment score, but are not user-friendly. We present a novel way to describe a patient’s visual function as a combination of visual acuity and visual field assessment that is simple to use and can be used by surgeons, and researchers to gauge visual outcomes following tumor resection.

Methods: The Unified Visual Function Scale is designed to include clinically relevant outcome factors affecting patients, as well as being sensitive enough to capture visual changes in a quantitative manner. We combine visual acuity and visual fields into three categories designed around the definition of legal blindness and fitness to drive in Canada. We then applied the scale to our previously published case series of 53 patients with perisellar meningiomas to test sensitivity and specificity for assessment of overall visual outcomes for patients undergoing craniotomy for tumor resection. We then compared the results against previously documented visual loss scales in the literature.

Results: While previously designed visual outcome scales provide a detailed assessment of visual change following surgery, are unfortunately not practical for daily clinic use by clinicians. An ideal scale would be quick to apply while being descriptive using practical factors. With our scale we were able to capture the overall visual change while being sensitive enough to define the overall quantity of improvement or worsening quantitatively, using categories that rare clinically relevant and understandable.

Conclusion: The Unified Visual Function Scale is a robust way to assess a patient’s vision combining visual fields and acuity. The implementation of pre and postoperative assessment is both sensitive enough to assess overall change, while providing clinically relevant information for surgeons, and allows for comparisons between treatment groups.