Cataract surgery may reduce the rate of cognitive decline and improve vision, cognition, and quality of life in dementia patients, new research suggests.
Preliminary results from an ongoing prospective study conducted by investigators at Case Western University in Cleveland, Ohio, showed that in a cohort of patients with dementia and clinically significant cataracts, immediate cataract surgery improved visual acuity, visual quality of life, and behavioral symptoms. It also appeared to slow the rate of cognitive decline, decrease neuropsychiatric symptoms, and reduce caregiver stress.
“Patients who had immediate surgery maintained their MMSE [Mini–Mental State Examination] scores, whereas the delayed group went down by 2.5 points ― that is, as big or bigger than we see with any of the Alzheimer’s disease drug trials,” principal investigator Alan J. Lerner, MD, director, Brain Healthy and Memory Center, and a staff neurologist at University Hospitals Case Medical Center said.
The study was presented here at the Alzheimer’s Association International Conference (AAIC) 2014.
Reluctance to Operate
Although Alzheimer’s disease, other dementia types, and cataracts are frequently comorbid, healthcare providers are often reluctant to operate, the investigators note.
“The clinical issue is that patients may not be getting cataract surgery simply because they have dementia. Families often don’t want to put them through it, and even doctors will often not recommend cataract removal ― whether it is a geriatrician, an internist, or even an ophthalmologist,” said Dr. Lerner.
To evaluate the impact of cataract surgery on vision, cognition, and quality of life, the investigators recruited patients from dementia and ophthalmology clinics who were diagnosed with dementia and visually significant cataracts.
The trial included 2 cohorts ― an intervention group that underwent surgery immediately following trial enrollment (n = 28) and a control group that either refused surgery or delayed surgery for 6 months (n = 14).
In addition to visual acuity and cataract severity, cognitive status was measured using the MMSE and the Alzheimer’s Disease Assessment Scale, Cognitive (ADAS-Cog).
The Neuropsychiatric Inventory (NPI) was used to assess patients’ psychiatric symptoms, including anxiety, confusion, depression, and hallucinations, and caregiver stress was measured by NPI- Distress.
Participants were assessed at baseline before surgery and again at 6 months. The mean age of the study participants was 80 years for the intervention group and 83.6 years for the control group. In addition, Dr. Lerner noted that from a cognitive standpoint, the study population was “quite impaired,” with mean MMSE scores of 18.75 and 16.93 for the intervention and control groups, respectively.
The analysis revealed that all patients in the intervention group had significantly improved vision. This may seem like an obvious result, said Dr. Lerner, but he pointed out that cataract surgery is not always a “slam dunk,” so “it’s good to know that vision does get better” in this patient population.
Secondly, noted Dr. Lerner, those who underwent immediate surgery experienced an improvement of 0.39 points in MMSE scores compared with a 2.31-point decline in the control group.
Results also showed a decrease in NPI scores of -4.71 in the intervention group compared with 3.92 in control individuals. Finally, NPI-Distress scores revealed a reduction in caregiver stress of -2.00 in the intervention group vs 0.93 in the control group.
“One of the most striking things to me was the reduction in neuropsychiatric symptoms in patients and the reduced caregiver burden and stress,” said Dr. Lerner.
Although the mechanism between improved vision and the reduced rate of cognitive decline is not entirely clear, he speculated that it is likely an indirect effect.
He noted that sensory deprivation is associated with hallucinations, anxiety, and other psychiatric symptoms. Poor vision and subsequent cognitive decline may be the result of an inability to interact with the environment, he said.
Although preliminary, Dr. Lerner said the study’s findings send a strong message, not just with respect to dementia patients with cataracts but potentially for dementia patients with other comorbid conditions.