Abstract
Purpose:
Lewy Body Disease (LBD) is a neurodegenerative disease affecting older individuals, that is characterized by visual hallucinations, fluctuations in cognition and parkinsonism. It is associated with deficits in both the dopaminergic and cholinergic systems. These neurotransmitters play a role in the processing of visual information. Therefore, the present study was undertaken to verify if contrast acuity was altered in LBD.
Methods:
Twelve participants with a confirmed diagnosis of LBD (Avg: 76.0 yrs ± SD 6.1) and 12 age-matched controls (Avg: 75.1 yrs ± SD 6.5) were recruited for the study. All subjects received a complete eye examination prior to testing to ensure that they had a visual acuity better than 20/30 and good ocular health. The eye with best corrected visual acuity was chosen for testing. Contrast sensitivity and contrast acuity were measured at an 8 foot distance with a retroilluminated CSV-1000 system (VectorVision) having a mean luminance of 85 cd/m2. Contrast sensitivity was measured with the CSV-1000E chart test face for 4 spatial frequencies: 3, 6, 12 and 18 cycles per degree (cpd). Contrast acuity was measured with the CSV-1000CVA20/30 chart test face for 3 contrast levels: 100%, 9% and 6%. Statistics consisted of ANOVAs for an alpha level of 0.05.
Results:
Our results indicated that the contrast sensitivity was significantly reduced in subjects with LBD for the 3, 12 and 18 cpd gratings (p< 0.01). Contrast acuity was also reduced in subjects with LBD, for all contrast levels tested (p< 0.01).
Conclusions:
These results show that LBD is associated with a reduction in contrast acuity for both gratings and letters. These findings may be related to dopaminergic/cholinergic deficits, or to structural anomalies known to occur in the retina of individuals with LBD.