作者：Allison Gandey
出處：WebMD醫學新聞
February 24, 2010 — 研究者報告指出，失智病患常有眼科異常，不佳視力若未治療會惡化認知衰退。
第一作者、密西根大學的Mary Rogers博士向Medscape Psychiatry表示，視力問題會有嚴重的後遺症，我們的研究與其他研究指出視力不佳與認知衰退、失智、阿茲海默氏症有關。
一個國際營養與老化工作小組已經正式提出將視力檢查納入失智病患評估中的建議。
在這個新分析中，研究者彙整「Health and Retirement Study」這項研究與Medicare保險共625名年長病患的資料，研究對象在開始時的認知為正常。
Rogers博士以及同樣來自密西根大學的Kenneth Langa醫師發現，研究開始時視力良好或極佳的人，在平均8.5年的追蹤期間內，失智風險降低63%。
他們表示，在那些最後發生認知不全或失智者，視力不佳更是常見，不到10%的失智病患在開始時有極佳的視力。
表、開始時的視力與之後的認知狀態
開始時的視力 | 認知正常、 % | 認知不佳但無失 智、 % | 失 智、 % |
極佳 | 30.7 | 14.5 | 9.7 |
很好 | 29.5 | 27.2 | 20.7 |
好 | 28.4 | 37.3 | 45.0 |
普通 | 9.0 | 17.9 | 20.2 |
不佳 | 2.4 | 2.9 | 4.1 |
眼盲 | 0 | 0.3 | 0.3 |
研究者指出，視力較不佳且未前往眼科就診者，發生阿茲海默氏症的風險增加9.5倍。
十月時，研究者在美國眼科學會與泛美眼科協會聯合年會的發表中，討論阿茲海默氏症視力變化的診斷挑戰。
失智病患一般會有無法解釋的視力喪失，通常包括讀寫困難的症狀，這可能難以診斷，因為視力、裂隙燈、眼底檢查等結果通常是正常的。
瑞士洛桑Jules Gonin眼科醫院的眼科醫師Pierre-Francois Kaeser在會議中表示，我們的研究中，許多病患已經向2-3位眼科醫師就醫，但是依舊沒有診斷。
Rogers醫師向Medscape Psychiatry表示，但是，這個新研究將此議題帶往另一個層次，認為未經治療的不佳視力與後來的所有失智有關，我們的研究與其他之前的證據顯示，視力問題發生在認知衰退症狀之前。
Rogers醫師描述麻省理工學院神經科醫師們的另一篇研究，認為缺乏視力改變了腦部功能，她表示，他們提出了關於腦部如何實際改變和重新連結的精闢論述。
【眼科檢查很重要】
Rogers醫師指出，我認為，我們的研究中最令人驚訝的是，治療視力異常可以延遲失智之診斷。
阿茲海默氏症協會醫療與科學官員主任William Thies博士指出，這個觀察型研究有其限制，本研究使用的方法是資料庫研究，不過，不能和臨床試驗的結果混淆。
Thies博士指出，該研究中，統計上的關聯不一定能指出因果關係，他指出，一點也不清楚這關聯是眼科疾病加速了失智症出現、或者是視力問題是後來失智的前驅。
Thies博士表示，不論有無此研究，有視力問題者應儘可能獲得關於這些問題的最佳照護，出現失智不應阻礙人們接受所有疾病的標準醫療照護，阿茲海默氏症協會經常從個案與家屬之間聽到這類問題。
國家老化研究中心協助資助本研究，研究者宣告沒有相關財務關係。
Am J Epidemiol. 線上發表於2010年2月11日。
Eye Examination Important Part of Medical Care for Dementia Patients
By Allison Gandey
Medscape Medical News
February 24, 2010 — Ophthalmologic abnormalities are common in patients with dementia, report researchers, and untreated poor vision may intensify cognitive decline.
"Vision problems can have serious consequences," lead investigator Mary Rogers, PhD, from the University of Michigan at Ann Arbor, told Medscape Psychiatry. "Our study and others link poor vision to cognitive decline, dementia, and Alzheimer's disease."
An International Academy on Nutrition and Aging task force has already formally proposed including vision testing as part of the evaluation of dementia patients.
In this new analysis, researchers combined data from the Health and Retirement Study and Medicare files to follow up 625 elderly patients. Participants had normal cognition at baseline.
Dr. Rogers and Kenneth Langa, MD, also at the University of Michigan, found that people with very good or excellent vision at baseline had a 63% reduced risk of dementia during a mean follow-up period of 8.5 years.
They show that poorer vision was more prevalent in those who eventually developed cognitive impairment or dementia. Less than 10% of dementia patients had excellent vision at baseline.
Table. Vision at Baseline and Later Cognitive Status
| Vision at Baseline | Cognitively Normal, % | Cognitively Impaired Without Dementia, % | Dementia, % |
| Excellent | 30.7 | 14.5 | 9.7 |
| Very good | 29.5 | 27.2 | 20.7 |
| Good | 28.4 | 37.3 | 45.0 |
| Fair | 9.0 | 17.9 | 20.2 |
| Poor | 2.4 | 2.9 | 4.1 |
| Blind | 0 | 0.3 | 0.3 |
The investigators show that people with poorer vision who did not visit an ophthalmologist had a 9.5-fold increased risk of developing Alzheimer's disease.
In October, investigators presenting at the American Academy of Ophthalmology Joint Annual Meeting With the Pan-American Association of Ophthalmology discussed the challenges of diagnosing a visual variant of Alzheimer's disease.
The unusual type of dementia is characterized by unexplained vision loss and often presents with symptoms such as difficulty reading and writing. It can be difficult to diagnose because the results of standard eye examinations, such as visual acuity, slit lamp, and fundus examination, are often normal.
Vision problems can have serious consequences.
"Many of the patients we studied had already seen 2 or 3 ophthalmologists and still did not have a diagnosis," Pierre-Francois Kaeser, MD, an ophthalmologist at the Jules Gonin Eye Hospital in Lausanne, Switzerland, said at the meeting.
But this new study takes this issue to the next level, suggesting that untreated poor vision is related to all late-life dementia. "Our study and others provide evidence that the visual problems preceded the symptoms of cognitive decline," Dr. Rogers told
Medscape Psychiatry.
Dr. Rogers described additional work by Massachusetts Institute of Technology neurologists that suggested that a lack of visual input alters the brain. "They gave a fascinating talk on how the brain actually changes and rewires," she said.
Eye Examinations Important
"I think what was most surprising in our work is that treating visual disorders appeared to delay the diagnosis of dementia," Dr. Rogers added.
William Thies, PhD, chief medical and scientific officer at the Alzheimer’s Association, points to the limits of this observational study. "The methodology used in this study is common for database research. However, it should not be confused with the results from a clinical trial."
Dr. Thies points out that the statistical correlations identified in the study do not necessarily indicate causality. "It is not at all clear whether the relationship is due to eye disease accelerating the appearance of dementia or whether the vision problem is a precursor to later dementia," he noted.
"With or without this study, people with vision problems should do their best to obtain the standard of care for those problems," Dr. Thies said. "The presence of dementia should not preclude people receiving the standard of medical care in all cases, which, from what the Alzheimer’s Association hears from individuals and families, happens too often."
The National Institute on Aging helped fund this study. The researchers have disclosed no relevant financial relationships.
Am J Epidemiol. Published online February 11, 2010.
