单选题 12. Although initially symptomless, glaucoma can eventually cause blindness when not properly treated. Tests under laboratory conditions of the traditional treatment, daily administration of eyedrops, show it to be as effective in relieving the internal ocular pressure that causes glaucoma as is a new laser-surgical procedure. Yet glaucoma-related blindness occurs in a significantly smaller percentage of patients who have had the surgery than of patients for whom only the eyedrop treatment was prescribed.
Which of following, if true, most helps to explain the low rate glaucoma-related blindness among patients who had the surgery? ______

A、 Glaucoma-related blindness is no more common among patients who have had only the surgery than it is among patients who had the surgery after using the eyedrops
B、 Doctors rarely recommend the surgery for glaucoma patients who have already started the traditional course of treatment
C、 There is no known physiological cause of glaucoma other than increase in pressure inside the eye
D、 A significant percentage of the people for whom the eyedrop treatment has been prescribed fail to follow the prescribed daily regimen, because the eyedrops have unpleasant side effects.
E、 The eyedrops traditionally prescribed to treat glaucoma are normally prescribed to treat other disease of the eye.

【正确答案】 D

【答案解析】 D：既然眼药水因为副作用导致很多人不会遵医嘱，因此只滴眼药水而失明的人的比例会高于做手术而失明的人的比例，就算理论上两种方法治疗效果一样。正确。
A：该选项本质上只是在讨论手术，而没有讨论手术和传统疗法的区别，与原文无关，不选。
B：该选项说明传统疗法和手术一样有效，属于重复原文，无法解释文中矛盾，不选。
C：该选项只能说明眼药水和做手术确实是有效的，但是没法解释为什么做手术的人失明的比例更小。
E：本文就是在讨论眼药水在青光眼治疗上的有效性，与其他眼疾无关，不选。