Reversible Metal Frame Occluding Glasses. This product is preferable to using a Pirate Patch and to having the patient cover an eye with his hand. While blind spot mapping is not a visual acuity assessment, some patients will find it easier to perform the testing while wearing their prescription or reading glasses. The occluder glasses fit over their glasses. These glasses are reversible, meaing that you just flip them over to cover the eye not being tested. This price includes shipping fees.