A.early stage B.ictal stage C.expansion stage D.maturity stage 21.Cataract affects which partof the eye? A.Retina B.Lens C.Comea D.Vitreous 22.Who are more likely to get cataract? 合 C.Long term steroid use D.All of the above 23.Diabetic retinopathy is A.a complication of diabetes of damage to the reina of the ey dness D.all of the above 24.Diabetic retinopathy has A.two stages. B.three stages C.fourstages. D.None of above 25.When light passes from one medium to another with a different refractive index,which of the following may occur? A.diffraction B Reflection C.Refraction D.interference 5 A. early stage B. ictal stage C. expansion stage D. maturity stage 21．Cataract affects which part of the eye? A. Retina B. Lens C. Cornea D. Vitreous 22．Who are more likely to get cataract? A. Diabetics B. Eye trauma C. Long term steroid use D. All of the above 23. Diabetic retinopathy is A. a complication of diabetes. B. a leading cause of blindness. C. a result of damage to the retina of the eye. D. all of the above 24. Diabetic retinopathy has A. two stages. B. three stages. C. four stages. D. None of above 25. When light passes from one medium to another with a different refractive index, which of the following may occur? A. diffraction B. Reflection C. Refraction D. interference