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Optics. Mirrors and lenses are the critical light-bending components of a telescope. Objective: The first lens or curved mirror that collects and focuses the incoming light. Primary lens: The objective of a refracting telescope. Primary mirror: The objective of a reflecting telescope. Corrector plate: A full aperture negative lens placed before ...
Contact lenses. to correct refractive errors of the eye; a little invasive. Phoropter. used in refraction testing. Tonometers. used to determine the intraoccular pressure (IOP) - useful in glaucoma; video link for various types of tonometers. Speculum: to keep the eyes open during any operation. Universal eye speculum.
Think of the eye as a camera. A camera needs a lens and a film to produce an image. In the same way, the eyeball needs a lens (cornea, crystalline lens, vitreous) to refract, or focus the light and a film (retina) on which to focus the rays. If any one or more of these components is not functioning correctly, the result is a poor picture.
Pupillary light reflex. Variation in the size of the pupil in bright (left) and dim (right) environments. In this case the pupil is 3 mm in diameter on the left, and 9 mm on the right. The pupillary light reflex ( PLR) or photopupillary reflex is a reflex that controls the diameter of the pupil, in response to the intensity ( luminance) of ...
Diagram of a human eye (horizontal section of the right eye) 1. Lens, 2. Zonule of Zinn or Ciliary zonule, 3. Posterior chamber and 4. Anterior chamber with 5. Aqueous humour flow; 6. Pupil, 7. Corneosclera or Fibrous tunic with 8. Cornea, 9. Trabecular meshwork and Schlemm's canal. 10. Corneal limbus and 11. Sclera; 12. Conjunctiva, 13. Uvea ...
Visual system. The visual system includes the eyes, the connecting pathways through to the visual cortex and other parts of the brain (human system shown). The eye is the sensory organ of the visual system. The iris, pupil, and sclera are visible. Identifiers.
A single-lens reflex camera ( SLR) is a camera that typically uses a mirror and prism system (hence "reflex" from the mirror's reflection) that permits the photographer to view through the lens and see exactly what will be captured. With twin lens reflex and rangefinder cameras, the viewed image could be significantly different from the final ...
A telephoto lens, also known as telelens, is a specific type of a long-focus lens used in photography and cinematography, in which the physical length of the lens is shorter than the focal length. [1] : 93 This is achieved by incorporating a special lens group known as a telephoto group that extends the light path to create a long-focus lens in ...