I've done my initial CASA class 1 medical not too long ago in London. You'll have an extended eye examination checking your visual acuity, ishihara color test, visual field test, slip lamp test and eye pressure check. You will be fine also if wearing glasses al long as your corrected binocular vision is 6/6 and your single eye is at least 6/9. No restriction about refraction.
Regarding the medical it took less than an hour and they will do an ECG, audiogram, misure your blood pressure, check urine and blood for colesterol, sugar, lipids and drug test. Plus some annoying paperwork and that's it. Hope it helps
