Boop J J, van Dalen J T, Tyner G S
Department of Ophthalmology and Visual Sciences, Texas Tech University Health Sciences Center School of Medicine, Lubbock 79430.
Br J Ophthalmol. 1987 Oct;71(10):797-802. doi: 10.1136/bjo.71.10.797.
Objective measurements of visual acuity were determined with the Catford drum in 82 eyes of patients in our Low-Vision Clinic who typically suffered from visual loss due to macular disease. The results were compared with subjective measurements of visual acuity by the Snellen chart. The findings indicated a significant overestimation of Snellen visual acuities by the Catford drum in 90.2% of eyes tested by a factor of 1.05 to 20.0, average 4.73. The correlation coefficient for the study was +0.40. This differs from the original results of Catford and Oliver in 1971. In addition, the Catford drum was used on follow-up visits in the same patients to assess 'visual performance'. The initial results showed an improvement in visual acuities when the Catford drum was used in 12 of 15 patients, while the Snellen acuities remained stable when retested after one month of basic instruction and use of standard low-vision aids. This improvement in 'Catford' acuity was by a factor of 0.3 to 10.0, average 4.08. This is thought to represent the patient's ability to learn the use of eccentric viewing or parafoveal retinal areas for vision. It confirms previous intuitive findings and helps to explain why low-vision patients seem to function at a higher level than expected from their Snellen visual acuities.
我们低视力门诊的患者中，82只眼睛使用卡特福德鼓进行了视力的客观测量，这些患者通常因黄斑疾病而视力受损。将结果与用斯内伦视力表进行的视力主观测量结果进行了比较。研究结果表明，在90.2%的受测眼睛中，卡特福德鼓对斯内伦视力的高估幅度为1.05至20.0倍，平均为4.73倍。该研究的相关系数为+0.40。这与卡特福德和奥利弗1971年的原始结果不同。此外，在对同一患者的随访中使用卡特福德鼓来评估“视觉表现”。初始结果显示，15名患者中有12名在使用卡特福德鼓时视力有所改善，而在经过一个月的基本指导和使用标准低视力辅助工具后重新测试时，斯内伦视力保持稳定。“卡特福德”视力的这种改善幅度为0.3至10.0倍，平均为4.08倍。这被认为代表了患者学习使用偏心注视或中央凹旁视网膜区域进行视力的能力。它证实了先前的直观发现，并有助于解释为什么低视力患者的功能水平似乎高于其斯内伦视力所预期的水平。
