There are many possible causes of blurred vision, including diseases of the cornea, lens, and retina. Myopia can cause blurred vision in the distance, farsightedness can cause blurred vision in the near distance, and astigmatism can cause double vision and vision loss, which can be treated with glasses of the right prescription. Older patients should consider the case of cataract, which generally shows gradual vision loss without other discomforts such as obvious eye pain, itchiness, and suffocation, etc. An examination can reveal lenses with different degrees of clouding, and depending on the severity and the degree of impact on vision and life, observation or surgery can be performed, and surgery is currently the only way to treat cataract.