Abstract
Purpose: :
To determine the pupillary response to dilute pilocarpine, retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) thickness in patients with Alzheimer’s disease (AD) compared to age-matched healthy patients.
Methods: :
9 individuals with AD and 9 healthy age-matched controls were included in this study. Subjects with anisocoria, with a history of any ocular pathology or any known cause of RNFL and GCL alteration were excluded. Informed consent was obtained from all subjects prior to examination. After neurologic and complete ophthalmologic examination, pupillary diameter was registered before and 30 minutes after the administration of 2 drops of diluted pilocarpine (0,125%). RNFL and GCL thickness was measured using a spectral-domain optical coherence tomography (SD-OCT), with Topcon 3D OCT-2000 (Topcon Medical Systems. Tokyo, Japan) and Cirrus HD-OCT (Carl Zeiss Meditec. Jena, Germany). RNFL thickness examination included total and superior, nasal, temporal and inferior subfield measurement. GCL included superior and inferior subfield measurement.
Results: :
Patients with AD showed a higher response to dilute pilocarpine, with a mean decrease in pupillary diameter of 1,9mm, compared to 0,9mm in the control group. This change did not reach statistical significance (p=0,433). Total and subfield distribution of RNFL thickness was similar between the two groups (p value between 0,184 and 0,874), and no significant differences in GCL thickness of superior and inferior subfield were observed between individuals with AD and healthy controls (p value between 0,177 and 0,199).
Conclusions: :
Our data indicate that patients with AD show a tendency to be more responsive to dilute pilocarpine test than age-matched controls. This may represent a useful tool in the detection of AD patients. Despite other studies reporting the contrary, we could not find any difference in RNFL or GCL thickness measured with sd-OCT in patients with AD compared to the control group.
Keywords: pupillary reflex • retina • nerve fiber layer