Maintaining vision is crucial for healthy aging. Numerous studies focus on vision impairments caused by disease, aging, and ocular trauma, leading to the development of a wide range of lenses, implants, and biomedical devices aimed at correcting vision. Contact lenses are the most commonly used biomedical devices for individuals who prefer not to wear glasses, correcting mild ametropia (a general term for refractive errors such as myopia, hyperopia, and astigmatism, where the eye fails to focus images sharply on the retina). However, in cases such as severe anisometropia (differences in refractive power between the two eyes), regular astigmatism, and irregular astigmatism, contact lenses are the only option for vision correction. Similarly, intraocular lenses are essential for treating cataracts, a condition that can lead to blindness if left untreated. Hydrogels form the fundamental biomaterial in ophthalmology, with applications ranging from contact lenses to flexible intraocular lenses and ophthalmic drug delivery systems. This chapter examines the hydrogels used in the manufacture of contact lenses and intraocular lenses.