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Optical systems in the eye, a field revolutionized by Allvar Gullstrand's groundbreaking research, encompass the intricate mechanisms responsible for vision. Through his pioneering work, Gullstrand unraveled the complex interactions of light as it enters the eye, illuminating the processes involved in image formation on the retina. His profound understanding of the eye's optical properties laid the groundwork for advancements in ophthalmology, optometry, and our overall comprehension of human sight.