[The investigation of retinal nerve fiber loss in Alzheimer's disease].

OBJECTIVE: To determine if there are retinal abnormalities in Alzheimer's disease and if retinal changes are one of the causes of the visual symptom, and if the changes of retina thickness correlated with the severity of dementia.
METHODS: Case-control study. Twelve patients of Alzheimer's disease and seventeen normal controls were included. General eye examinations, mini-mental state examination (MMSE) score and OCT were performed on each patient. Independent-samples t test was used to compare the results obtained from these two groups.
RESULTS: The retinal nerve fiber layer (RNFL thickness) overall:Alzheimer's (93.18 +/- 11.36) microm, control (99.44 +/- 8.88) microm, macula thickness min: Alzheimer's (204.00 +/- 52.06) microm, control (211.36 +/- 49.09) microm; inner 1 mm: Alzheimer's (232.50 +/- 23.37) microm, control (242.79 +/- 40.36) microm; between 1-3 mm: Alzheimer's (289.42 +/- 21.37) microm, control (298.43 +/- 23.30) microm; between 3 - 6 mm: Alzheimer's (256.67 +/- 20.04) microm, control (262.86 +/- 20.19) microm was thinner in the patients with Alzheimer's disease. Macula volume inner 1 mm: Alzheimer's (0.183 +/- 0.018) m(3), control (0.188 +/- 0.031) m(3): between 1 - 3 mm: Alzheimer's (1.819 +/- 0.134) m(3), control (1.875 +/- 0.147) m(3); between 3 - 6 mm Alzheimer's (5.443 +/- 0.424) m(3), control (5.571 +/- 0.428) m(3) in the Alzheimer's diseases patients was smaller than that of the controls. There was significant difference (t = -2.519, P < 0.05) in RNFL thickness of the superior quadrant between the two groups Alzheimer's disease (115.09 +/- 14.05) microm, control (129.23 +/- 10.69) microm.
CONCLUSIONS: There is retinal nerve fiber loss in patients with Alzheimer's disease, which may be responsible for the visual symptoms. The retinal nerve fiber loss is obviously in the superior quadrant, and it is correlated positively to the severity of dementia.