There are many ways to examine the eyeglasses, mainly focusing on diseases in specific parts of the eye. A comprehensive and systematic eye examination includes visual acuity, optometry, intraocular pressure, slit lamp, anterior ophthalmoscope, and funduscope for funduscopic examination, which provides a comprehensive and systematic understanding of the condition of the eye. Visual acuity examination is the first step into the eye examination. There are many diseases that cause vision loss, the common ones are corneal problems, cataract, glaucoma as well as lesions of the fundus and optic nerve. A slit lamp examination can reveal the anterior segment of the eye, including the conjunctiva, cornea, anterior chamber, iris-ciliary body, and the anterior 1/3 of the vitreous body. Problems of the vitreous retina and optic nerve can be detected by anterior ophthalmoscopy and fundoscopy. Optometry can be used to find out if there is any refractive error in the eye, and measurement of intraocular pressure is a basic test for screening glaucoma.