accomodation

• • Ability of lens to change shape to refract the correct amount of light. Allows focused images to form on retina ob objects at any distance. Shape can be changed by ciliary muscles and suspensory ligaments
• • 4 refractive mediums are cornea, aqueous humour, lens and vitreous humour. Light rays entering eye are refracted by combination of these structures to reach a focal point on retina to form a clear, inverted image
• • Distant objects: when the eye views distant objects, ciliary muscles relax, stretching suspensory ligaments. This causes the lens to lengthen, decreasing the curvature and reducing the refraction of light
• • Close objects: eye views close objects, ciliary muscles contract, relaxing suspensory ligaments. Causes lens to become rounder, increasing curvature and refracting light to a greater degree