Practical method:An ophthalmologic surgery department head operates on the patients at National Ophthalmologic Hospital "QUINZE VINGT" in Paris.The surgery involves the eye with the worst vision. Study analysis does not take into account the results of the second eye intervention. The surgery consists in a phacoemulsification and setting of an acrylic implant in the posterior chamber. Patients care consists in the usual procedures. The intervention is performed under regional anesthesia exceptionally general anesthesia. A three-day hospitalization is regular considering patients' fragility.The aim of the study is to analyze 3 months after cataract surgery, the different neuropsychological tests, with the help of appropriate statistics. The main endpoint criterion will be the NPI-test improvement between the one-month test before surgery and the three-month test after. A correlation between visual acuity improvement and NPI-test improvement will be verified. The second endpoint criterion will be the study of other scores (MMS, IADL, ADAS-cog, GDS or Cornell test), in a matched-way. If improvement is noted, a regression logistic study will permit to study improvement predictive factors. Each participant will take part in the study during 4+/-1 months.Study rationale and literature data abstract.Cataract treatment, restoring a better visual function, is greatly beneficial upon life quality of elderly people, as largely demonstrated (1, 2). Several studies, based on cognitive functions, daily life activities, and mood, showed a significant amelioration of elderly people operated on for cataract, in comparison with those who refused the intervention (3). Benefice is less in case of ocular co morbidity or in some very old patients (4).Cataract surgery on elderly patients suffering from cognitive decline has given rise to very few studies. Nevertheless, correlation between low vision and cognitive alteration is well established. In France, a Health High Authority (HHA) report devoted to cataract surgical treatment evaluation, based on literature data and experts opinion, was published in 2000 (6). The report dealt with the taking in care of demented or low mental capacities patients. It regretted that very few trials were undertaken for this problem.. In case of beginning dementia, the experts thought that cataract surgery visual benefice is limited. It seldom improves lecture but allows patients to watch television more and makes contacts with neighbors easier. In case of advanced dementia, the authors thought that surgery would worsen rapidly patients. The report evoked as well the paternalistic decisions taken without any dialogue with the involved patient and raised ethical issues. Still to-day, in case of dementia, the cataract management remains an actual problem. This is a challenge for closes, guardians, geriatrics', ophthalmologists and sometimes the decision is opposed to patients' feelings (8).One of the studies cited in the HHA report, based on few low-vision patients, showed after cataract surgery, a light improvement of mental status, everyday life but poor results on depression. After surgery, patients felt that they were not as fragile as they had thought, that they endured the operation and felt better after (9). In 2003, a Japanese study dealt with cognitive functions of 40 demented patients suffering from cataract. Results and showed that among the 20 patients who chose to be operated on, 60% were improved, 35% were unchanged, and 5% worsened (10). By extensive neuropsychological investigations on Alzheimer' patients, the VIVA study would show the impact of visual function improvement on cognitive functions, psychological and behavioural troubles, autonomy, and mood perturbations. Pointing out the objectives upon improvement of neuropsychiatric survey, namely the NPI test, the study would permit to precise the low-vision cataract role on patients' comportment troubles which are a cause of burn-out for caring people. It is clearly demonstrated that delirious manifestations, notably visual hallucinations are frequent in demented persons and in patients with low vision as well (9). In low-vision patients, it seems that only the cataract is significantly linked to visual hallucinations (10). The VIVA study aims to show also the benefice of a better visual function on behavioural non-disturbing troubles such as apathy and inhibition. Therefore, we would like to stress the cataract management benefits on Alzheimer's disease patients. Particularly, we intend to precise the extent of expected patients' improvement and to measure the correlation with visual acuity improvement