Hair cortisol concentration (HCC) may be an accurate biomarker of chronic stress in patients with retinitis pigmentosa (RP), according to a study published in Experimental Eye Research.

Researchers conducted an observational study at a single center between 2019 and 2021 consisting of patients with RP (n=78, mean age 51.59±13.40 years) and healthy controls (n=148, 41.29±5.14 years). The team collected 3 cm hair strands from all participants near the scalp and evaluated stress levels using the State-Trait Anxiety Inventory (STAI) questionnaire.

Among the RP cohort, 67% had severe RP, average disease duration was 25.4 (range, 2-50) years, and 74.35% had severe grade anxiety.

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Stratified by severe (n=52) and mild to moderate (n=26) RP status, severe disease was associated with poorer visual acuity (P =.001), more optic disc atrophy (P =.023) and bone spicules (P =.001), lower perimetry (P =.001), and thinner outer retinal thickness at the fovea (P =.001).

Researchers noted higher HCC levels among the RP cohort compared with controls (500.04±120.99 pg/mg vs 136.17±60.51 pg/mg; P <.001). Disease severity correlated with higher levels of HCC with a difference of 274.27 pg/mg measured between patients with severe RP and those classified as mild-moderate (P <.001). However, they observed no such association between self-reported anxiety levels and RP severity. 

“HCC as a clinical measure for long term cortisol exposure in patients with RP are elevated when compared to controls,” according to the investigators, who state that HCC has the potential to be a “promising tool to identify RP patients at risk of vision loss.”

This study was limited by a small sample size, single center design, underrepresentation of patients with mild RP, and failure to account for potential confounding factors such as hair dye or participant body mass index.


Mateos-Olivares M, Sobas EM, Puertas-Neyra K, et al. Hair cortisol level as a molecular biomarker in retinitis pigmentosa patients. Exp Eye Res. Published online March 6, 2022. doi:10.1016/j.exer.2022.109019