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NCLE REVIEW NAO
Biggest disadvantage of PMMA material is its lack of - Answer-Gas permeability Layer that makes up 10% of the cornea - Answer-Epithelium Vertical measurement for palpebral fissure - Answer-15mm Eyelid muscle responsible for lid closure - Answer-Orbicularis oculi A dense opacity of the cornea is called a: - Answer-leukoma Goblet cells that secrete that secrete mucous into tear film are located in which structure - Answer- Conjunctiva Transition zone between the bulbar conjunctiva and the palpebral conjunctiva is called - Answer-fornix Middle layer of the globe is mostly responsible for - Answer-Nutrition
Pupillary constriction is called - Answer-miosis Bactericidal ingredient found in the precorneal tear film is - Answer-Lysozyme The cornea is clear, and must remain clear, which means it must be ______, and be free from ______. - Answer-avascular, scarring what are tarsal plates? - Answer-two thin, elongated plates of dense connective tissue, about 2.5cm in length. Contributes to it's form and support. what is a prism ballast? - Answer-prismatic shape used in contact lens to stabilize the lens by preventing rotation how does one achieve the rotational control of truncation? - Answer-by making the bottom edge of the lens flat what are principal meridians? - Answer-the meridians of most and least curvature, or greatest and least power on a cylindrical or toric surface what is a bicurve lens? - Answer-lens consisting of two posterior curvatures; one central curve(base curve) and one peripheral curve a soft lens should have a curve and diameter that will allow it to drape the cornea, vault over the limbus, and extend how many mm into the sclera? - Answer-1mm what angle identifies the smallest angle? - Answer-minimum visual angle
Given Rx of -2.50 -2.00 x180 and K readings of 44.50 @180/46.50@90, determine the CPC - Answer-
Given the K's of 42.00@180/43.00@90, a CPC of 42.50, and a Rx of -1.00-1.00x180, what actual lens power would you order? - Answer--1. Given K's 42.00@180/43.00@90 what would be a good CPC - Answer-42. In placing the following Rx on an optical lens cross, identify the powers in the principle meridians -2.50- 1.00x180 - Answer--2.50@180/-3.50@ Formula for Diopters to radius of curvature - Answer-337.5/Diopters Rx of -4.75-2.50x180, and K's of 42.25@180/42.75@90, which of the following lens types would you fit on the patient? - Answer-Front surface toric GP the iris is a thin vascular membrane, averaging about ____mm horizontally and ____mm vertically - Answer-11/12, 9/ you can extend the range up to 61D by placing a ____ trial lens over the aperture closest to the patient. This extends up an additional ____ - Answer-+1.25, 9.00D Given a 4.00D toric power on the back surface of a back surface toric, how much toricity must be ground on the front surface? - Answer-6.00D Given an Rx of -11.00 sph, refracted a vtx.14mm, calculate the compensated power for a GP lens - Answer--11/100=.11x14=-1.54 then add -1.5 to -11 which then becomes -9.
fiven an Rx of +11.00 sph, refracted at Vtx.12mm calculate the compensated power for a GP lens - Answer-11/100=.11x12=1.32 then add 1.32 to 11 which then becomes 12.32=12.38(rounding) if a contact lens power is read with the anterior surface facing the examiner and the posterior surface toward the reticule of the lensometer, the reading is in what vertex power? - Answer-back vertex power a tool that measures the overall diameter of a contact lens - Answer-V-channel, hand measuring magnifier, shadowscope sodium fluorescein is used to evaluate tear - Answer-quality fluorescein temporarily stains tears but will not stain ____ since the fluorescein is a water soluble molecule that doesn't penetrate intact lipid cell membranes - Answer-intact epithelial cells what is a retinoscope used for? - Answer-determines the refractive state of the eye what is a phoropter used for? - Answer-a refractive device combining a large variety of spherical and cylindrical lenses, prisms, and occluders, used to determine the eye's optical correction how is a tetracurve lens designed? - Answer-four posterior curves, a central posterior curve, and three peripheral curves keratometry measures the central ____mm of the cornea - Answer-3mm what is the tolerance for overall diameter of a contact lens? - Answer-+/-.05mm for contact lenses, you need to compensate for vertex distance when the power is over what? - Answer- 4 diopters
what is the central posterior curve? - Answer-posterior radius of curvature desgned to conform to the apical zone of the cornea center thickness of a GP lens is measured with a lens gauge. what is the tolerance? - Answer-+/-. what is the first refracting medium of the eye? - Answer-precorneal tear film scribe marks on soft toric lenses are for? - Answer-to determine if the lens is aligned correctly on the cornea
