PNA Medical Corner: Visual Field Outcomes in Neurosurgery
This month the PNA Medical Corner focuses on an article co-authored by six members of the PNA, including Drs. Barkhoudarian, Gardner, Prevedello, Kelly, White, and Little. The study looks at the way visual field outcomes are reported in neurosurgical case series and finds significant variations. It concluded that standardized VF data collection guidelines may improve reliability.
World Neurosurg. 2018 Aug 22. pii: S1878-8750(18)31852-7. doi: 10.1016/j.wneu.2018.08.069. [Epub ahead of print]
Visual field outcome reporting in neurosurgery: Lessons learned from a prospective, multicenter study of transsphenoidal pituitary surgery.
Mooney MA1, Herro AM2, Fintelmann RE3, Mayberg MR4, Barkhoudarian G5, Gardner PA6, Prevedello DM7, Chicoine MR8, Kelly DF5, Chandler JP9, Jahnke H1, White WL1, Little AS10.
Visual field (VF) outcomes are commonly reported in neurosurgical case series; however, substantial variability can exist in VF testing and outcome reporting. We sought to evaluate the challenges of VF testing and to develop detailed recommendations for VF outcome reporting by analyzing results from an ongoing, multicenter study of transsphenoidal pituitary surgery.
VF testing results were collected during a prospective, multicenter clinical trial evaluating patient outcomes after transsphenoidal surgery for nonfunctioning pituitary adenomas (TRANSSPHER; ClinicalTrials.gov NCT02357498). Two independent ophthalmologists reviewed the reliability and outcomes of all VF studies. Preoperative and postoperative VF studies were evaluated individually and as preoperative-postoperative pairs.
Suboptimal perimetry field settings were reported in 37% of VF studies. Automated reliability criteria flagged 25%-29% of VF studies as unreliable, whereas evaluation by two independent ophthalmologists flagged 16%-28%. Agreement between automated criteria and raters for VF reliability was inconsistent (kappa coefficients, 0.55-0.83), whereas agreement between the two raters was substantial to almost perfect (kappa coefficients, 0.78-0.83). Most patients demonstrated improvement after surgery (rater 1, 67%; rater 2, 60%), with substantial rater agreement on outcomes for paired examinations (kappa coefficient, 0.62).
VF outcome studies demonstrated significant variability of test parameters and patient performance. Perimetry field settings varied between patients and for some patients, preoperatively compared with postoperatively. Reliance on automated criteria alone could not substitute for independent ophthalmologist review of test reliability. Standardized guidelines for VF data collection and reporting could increase the reliability of results and allow for better comparisons of outcomes in future studies.