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IOLs usually consist of a small plastic lens with plastic side struts, called haptics, to hold the lens in place in the capsular bag inside the eye. [2] IOLs were originally made of a rigid material , although this has largely been superseded by the use of flexible materials, such as silicone. Most IOLs fitted today are fixed monofocal lenses ...
The function of multifocal IOL depends on the pupil size for refractive types. The concept is based on the principle that the pupil tends to constrict for near tasks, so the central portion of the lens is designed for near and the outer portion for distance.
Toric IOLs were introduced in 1992 and are used worldwide to correct corneal astigmatism during cataract surgery; [39] [1] they have been approved by the FDA since 1998. [42] Also in the late 1990s, optical biometry based on partial coherence infrared interferometry was introduced: this technique improves visual resolution, offers much greater ...
Multiple studies have shown a 12–17 μm/year decrease in the anterior chamber depth with aging. [6] [7] If a phakic IOL patient is assumed to have a 50-year lifespan, the overall decline in ACD may add up to 0.6–0.85 mm, long-term data about this effect are not available. This concern is more important in implantable collamer lens because ...
The aim of an accurate intraocular lens power calculation is to provide an intraocular lens (IOL) that fits the specific needs and desires of the individual patient. The development of better instrumentation for measuring the eye's axial length (AL) and the use of more precise mathematical formulas to perform the appropriate calculations have significantly improved the accuracy with which the ...
Name Example Notes Afterimage illusion An afterimage or ghost image is a visual illusion involving an image continuing to appear in one's vision after the exposure to the original image has ceased. Afterimage on empty shape (also known as color dove illusion) This type of illusion is designed to exploit graphical similarities. Ambiguous image
Note 2: The droplets may be amorphous, liquid-crystalline, or any mixture thereof. Note 3: The diameters of the droplets constituting the dispersed phase usually range from approximately 10 nm to 100 μm; i.e., the droplets may exceed the usual size limits for colloidal particles. Note 4: An emulsion is termed an oil/water (o/w) emulsion if the
Fig 3: Animation showing glued IOL surgery. Note the flaps made on the white portion of the eye (sclera). The IOL is injected inside the eye and one end (haptic) is grasped with the glued IOL forceps Fig 4: Glued IOL surgery. The IOL is inside the eye. Both the haptics (blue color) are externalized under the scleral flaps.