Abstract
Purpose: :
Visual hallucinations have been associated with reduced visual acuity. We investigated the association of hallucinations with contrast sensitivity and acuity in low vision rehabilitation patients.
Methods: :
As part of a larger prospective cohort study, 225 patients referred for low vision rehabilitation were specifically asked about the symptom of seeing formed visual hallucinations (VH). Contrast sensitivity (CS) was measured with Pelli–Robson chart. Acuity and contrast sensitivity values were divided into quartiles.
Results: :
Mean age was 79.83 years with 62% patients (140/225) having a diagnosis of AMD and 36% (80/225) having acuity better than or equal to 6/18 in their better eye. Of 225 patients enrolled 78 (35%) reported hallucinations. Poorer visual acuity was associated with report of hallucination (odds ratio = 2.95 , p=0.01). After adjusting for visual acuity in the better eye, patients with the poorest two levels of CS (< log 1.20, < log 0.75) were more likely to report VH (adjusted OR: 5.47, 95% CI:1.26, 23.72 and adjusted OD: 5.01, 95% CI: 1.06, 23.68).
Conclusions: :
Contrast sensitivity is significantly associated with visual hallucinations independent of acuity. Patients with contrast perception deficits, even without significant acuity loss, are at risk for hallucinations.
Keywords: contrast sensitivity • low vision • visual acuity