Nystagmus is a visual condition in the eye that the patient cannot control. When the eye twitches, it will make the eye unable to see an object clearly, affecting the patient's ability to see.

Choroidal neovascularization is one of the dangerous complications of many different diseases, in which severe myopia has the highest rate of choroidal proliferation. Poorly functional and fragile blood vessels cause complications that seriously affect the patient's vision.