There are a number of reasons why your eyes may look small or large, the most common being the following: First, ptosis, which is caused by the ptosis of one eye because the upper eyelid cannot be lifted up, making the onset of the eye look smaller, or in severe cases, even unable to lift the upper eyelid up at all. Ptosis can be corrected surgically to make both eyes look symmetrical. Secondly, due to congenital microphthalmos, the monocular onset of congenital microphthalmos, because of the small diameter of the eyeball will lead to eyeball depression, resulting in the appearance of both eyes asymmetric. Third, due to atrophy of the eyeball, such as monocular stigmata retinal detachment, endophthalmitis, etc., resulting in long-term low intraocular pressure and ultimately causing atrophy of the eyeball, which will make this eye look smaller. Fourth, due to congenital glaucoma, monocular congenital glaucoma, will lead to the onset of eye dilation under the action of high intraocular pressure, which will make the eye look larger.