بخشی از پاورپوینت
--- پاورپوینت شامل تصاویر میباشد ----
اسلاید 1 :
فهرست مطالب
¬ خلاصه ای از آناتومي چشم
¬ تقسیم بندی تجهیزات چشم پزشكي
¬ معرفی تجهیزات
¬ فیلم کوتاهی از عمل کاتاراکت با فیکو
اسلاید 2 :
¬The outer wall of the eye is formed by the hard, white sclera.
¬Cornea is the clear portion of the sclera.
¬2/3 of the refraction takes place at the cornea.
اسلاید 3 :
¬Colored iris controls the size of the opening (pupil) where the light enters.
¬Pupil determines the amount of light, like the aperture of a camera.
اسلاید 4 :
¬Eye lens is made of transparent fibers in a clear membrane.
¬Suspended by suspensory ligament.
¬Used as a fine focusing mechanism by the eye; provides 1/3 of eye’s total refracting power.
¬Non-uniform index of refraction.
اسلاید 5 :
¬The suspensory ligaments attach the lens to the ciliary muscle.
¬When the muscle contracts, the lens bulges out in the back, decreasing its focal length.
¬The process by which the lens changes shape to focus is called accommodation.
اسلاید 6 :
¬Transparent gelatinous liquid filling the eye.
¬Provides nutrients to the cornea and eye lens.
¬Also helps maintain the eyeball shape with its pressure.
اسلاید 7 :
¬Retina is the photosensitive “detector” for the eye.
¬Two types of receptors in the retina: rods for low light level, and cones for color.
¬Located at the center of the retina, fovea contains a greater concentration of cones.
¬Signals from the receptors leave through the optic nerve to the brain.
اسلاید 8 :
¬The retina is made of three layers:
–Plexiform layer is a network of nerves which carry the signals from the photo receptors.
–Photo receptors.
–Choroid provides nourishment to the receptors, as well as absorb any light that didn’t get absorbed by the photo receptors, like a antihalation backing in film.
اسلاید 9 :
¬Image focuses on the retina for a normal eye.
¬Distant objects look blurry for a myopic (near sighted) eye.
¬Near objects look blurry for a hyperopic (far sighted) eye.
اسلاید 10 :
¬Distant objects look blurry because the eye cannot relax any farther so that the image is focused before the retina.
¬Near object in focus without accommodation.
¬Corrected with a negative lens.
