Application of Unified Visual Function Scale; Parts I and II: Assessments Correlate with Patient Quality of Life and Are Reliable

Background: Historically, descriptions of visual acuity and visual field change following intracranial procedures have been very rudimentary. Clinicians and researchers have often used 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. We present a novel way to describe a patient’s visual function as a combination of visual acuity and visual field assessment—Unified Visual Function Scale (UVFS).

Objective: We have previously described and demonstrated its use to evaluate patients pre- and postoperatively following resection of lesions affecting the optic apparatus, a scale that uses combined visual acuity and visual fields evaluations to characterize patients into three categories designed around the definition of legal blindness and fitness to drive in Canada. To strengthen the applicability of the UVFS, we tested for inter- and intraobserver reliability of the UVFS and assessed whether UVFS scores reflect visual quality of life outcomes.

Methods: Eight independent observers (two medical students, two nurse practitioners, two neurosurgical trainees, and two neurosurgical staff members) were asked to assess visual acuity and visual fields and assign appropriate UVFS scores. These were then tested for inter- and intra-observer reliability. Additionally, Visual Function Questionnaire (VFQ-25) and Activities of Daily Vision Scale (AVDS) surveys were mailed out to 50 patients with previously-treated perisellar meningiomas. Pearson’s coefficient was calculated and analyzed for correlation against UVFS scores.

Results: We were able to demonstrate strong correlation between UVFS and general vision (0.77), near activities (0.73), peripheral vision (0.67) and driving (0.66) subdomains of VFQ-25. There was a strong correlation with ADVS overall score (0.59). We were able to compare UVFS grading to normative data and also demonstrate a strong link.

Conclusion: The Unified Visual Function Scale is a robust way to assess a patient’s vision combining visual fields and acuity. We believe it is reliable when used by clinicians, and its implementation in a clinical setting is strengthened by reflection of patient visual quality of life.

No conflict of interest has been declared by the author(s).