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An Intraocular lens (IOL) is a lens implanted in the eye usually as part of a treatment for cataracts or for correcting other vision problems such as short sightedness and long sightedness; a form of refractive surgery. If the natural lens is left in the eye, the IOL is known as phakic, otherwise it is a pseudophakic lens (or false
A monocle is a type of corrective lens used to correct or enhance the visual perception in only one eye. It consists of a circular lens placed in front of the eye and held in place by the eye socket itself. Often, to avoid losing the monocle, a string or wire is connected to the wearer's clothing at one end and, at the other end, to either a ...
Modern glasses with a rectangular lens shape. Corrective lenses can be produced in many different shapes from a circular lens called a lens blank. Lens blanks are cut to fit the shape of the frame that will hold them. Frame styles vary and fashion trends change over time, resulting in a multitude of lens shapes.
Subjective Refraction is a technique to determine the combination of lenses that will provide the best corrected visual acuity (BCVA). [1] It is a clinical examination used by orthoptists, optometrists and ophthalmologists to determine a patient's need for refractive correction, in the form of glasses or contact lenses. The aim is to improve ...
Iris-fixated intraocular lens is an intraocular lens that is implanted surgically into the eye and attached to the iris. Originally developed for aphakia, phakic versions have also been produced to correct myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. They are suited for correction of eyes where corneal refractive ...
Scleral lenses may be used to improve vision and reduce pain and light sensitivity for people with a growing number of disorders or injuries to the eye, such as severe dry eye syndrome, microphthalmia, keratoconus, corneal ectasia, Stevens–Johnson syndrome, Sjögren's syndrome, [1] aniridia, neurotrophic keratitis (anesthetic corneas), complications post-LASIK, higher-order aberrations of ...
The mask includes a fail-safe drinking device, a Secondary Speech Transmitter (SST) on the side [4] which a Clansman radio system microphone can be clipped to, and corrective lenses can be fitted to the eyepieces. The mask also contains an inner oro-nasal mask to decrease fogging on the lenses.
In lens systems, aberrations can be minimized using combinations of convex and concave lenses, or by using aspheric lenses or aplanatic lenses. Lens systems with aberration correction are usually designed by numerical ray tracing. For simple designs, one can sometimes analytically calculate parameters that minimize spherical aberration.