I came across this piece from a 2008 issue of Neurology recently, and wanted to keep it here for posterity. The conclusions of the study were clearly communicated by the title: “The “sunglasses sign” predicts nonorganic visual loss in neuro-ophthalmologic practice.”
In this seminal article, Bengtzen and colleagues performed a prospective analysis of all patients wearing sunglasses in clinic, and patients receiving diagnoses of “non-organic vision loss”, which was a technical term new to me. They report on a number of co-variates of this diagnosis, including the wearing of sunglasses inside the exam room, alongside “highly positive review of systems, workers’ compensation claim, disability, and lawsuit”.
Specifically, the reported sensitivity of wearing sunglasses for non-organic vision loss (NOVL) was 0.46 (95% CI 0.33 to 0.59). The prevalence of NOVL in the entire study population was 4.3% but 79% in sunglasses-wearing patients. The specificity of sunglasses for the diagnosis of NOVL was 0.995 (95% CI 0.989 to 0.998).
I found this interesting if only because it supports existing stereotypes about the wearing of sunglasses indoors. The article does not comment on why this relationship exists, nor does it suggest that the performance characteristics of this finding allow you to use it to rule in or rule out true vision threats, but it does shed some light on the patterns that shape our practice and color our perceptions.