Van Newkirk M R
Trans Am Ophthalmol Soc. 1997;95:715-49.
The Hong Kong Adult Vision Pilot Study is a population based study of the distribution and determinants of eye disease in a random sample of the Chinese population age 40 and over. The present pilot study identifies the extent and causes of visual loss using methods developed in the United States and Australia. The pilot study uses the prevalence data to estimate the sample size necessary to predict the size of an effect a larger study may detect and the confidence with which that effect may be considered and the standard deviation of the Hong Kong population. The smallest detectable odds ratios were calculated based on known risk factor prevalence rates of the pilot study.
Hong Kong Chinese residents aged 40 and over in 2 random cluster sites were identified by private household census. The examinations were performed at one location and included, health history and habits, presenting and best corrected LogMar vision, Humphrey visual field and IOP measurement, dilated slit lamp, fundus examination, fundus photography and echography.
In the two test sites, 355 people were examined of the 441 eligible residents (81% response). 76.6% of the population reported a change in vision in the last 10 years; 45% had not sought examination. 4.54% had vision less than 20/60. This was caused by: myopic choroidal degeneration (31%), cataract (19%), cataract + ARM (19%), ARMD (19%), glaucoma (6%), and corneal disease (6%). Vision loss increased significantly with age. Vision loss was more common in older women than in older men. The prevalence rates calculated from the pilot study data were used, requiring a relative precision of 95% and +/- 20% confidence interval of the prevalence rates, indicate that a sample size of 2500 would be a good number for a larger study.
The methods developed in the United States and Australia for completing eye disease prevalence studies are applicable in Hong Kong. Vision loss is increasingly common in older people and the percent of visual impairment in Hong Kong is higher than studies in the US and Australia. As the population ages demands on the health care systems will increase. The results from this pilot warrant continuation of the study. Efforts must be directed toward prevention of visual loss.
香港成人视力试点研究是一项基于人群的研究，旨在对40岁及以上中国人群的随机样本中的眼病分布及决定因素进行研究。本次试点研究采用美国和澳大利亚开发的方法来确定视力丧失的程度和原因。该试点研究利用患病率数据来估计为预测一项规模更大的研究可能检测到的效应大小、该效应可被认定的置信度以及香港人群的标准差所需的样本量。基于试点研究已知的风险因素患病率计算出最小可检测比值比。
通过私人住户普查确定了两个随机整群抽样地点中40岁及以上的香港中国居民。检查在一个地点进行，包括健康史和习惯、就诊时及最佳矫正的LogMar视力、Humphrey视野检查和眼压测量、散瞳裂隙灯检查、眼底检查、眼底摄影和眼部超声检查。
在两个测试地点，441名符合条件的居民中有355人接受了检查（应答率81%）。76.6%的人群报告在过去10年中有视力变化；45%的人未寻求过检查。4.54%的人视力低于20/60。其原因如下：近视性脉络膜变性（31%）、白内障（19%）、白内障+年龄相关性黄斑病变（19%）、年龄相关性黄斑变性（19%）、青光眼（6%）和角膜疾病（6%）。视力丧失随年龄显著增加。老年女性的视力丧失比老年男性更常见。根据试点研究数据计算的患病率，要求相对精度为95%且患病率的置信区间为±20%，这表明对于一项规模更大的研究，2500的样本量是合适的。
美国和澳大利亚开发的用于完成眼病患病率研究的方法适用于香港。视力丧失在老年人中越来越常见，香港的视力损害百分比高于美国和澳大利亚的研究。随着人口老龄化，对医疗保健系统的需求将会增加。本次试点研究的结果证明该研究有必要继续进行。必须致力于预防视力丧失。
