NCLE Practice Test Practical Verified A+ 2023

NCLE Practice Test Practical Steep Fluorescein Pattern - Bright green pooling center, very faint green pooling on diameter of lens Flat Fluorescein Pattern - Bright green pooling on diameter of lens, very faint green in center Against-the-rule Astigmatism Pattern - Bright green pooling horizontally, faint green pooling vertically With-the-rule Astigmatism Pattern - Bright green pooling vertically, faint green pooling horizontally Prism Ballast - Common technique to stabilize lens from rotating. Added thickness will position lens inferiorly (bottom of cornea) Truncation - Cutting off .50mm to 1.50mm of bottom edge of lens to provide stability. Reduces diameter, making a looser fit. Double Slab-off - Lens is thicker centrally and thinner at top and bottom of lens. Provides comfort to wearer, but may cause some stability issues. Aspheric Lens Design - Hyperflange - Used to correct high riding minus lenses. Myoflange - Used to correct low riding plus lenses. Monovision - Corrects presbyopia in contact wearers. One eye uses distance (dominant) and the other eye uses reading (resessive) Segment Bifocal - Same concept as spectacle bifocal. Must be prism ballast. Often crescent shaped. Toric Lenses - Anterior (front surface), back spherical surface or posterior (back surface), toric back curve Front Toric Lens - Corrects a low to moderate amount of corneal astigmatism Back Toric Lens - Corrects a mid to high amount of corneal astigmatism Bitoric Lens - Corrects 1.50D of corneal astigmatism and high residual astigmatism Aphakic - Condition of no crystalline lens Psuedophakic - Implant, intraocular lens Corneal Edema - Always causes a poor fitting lens Spectacle Blur - Temporary blurred vision upon switching from contact lenses to eyeglasses Crystalline Lens - The main focusing mechanism of the eye The Main Supply of Oxygen to the cornea is provided by - Tear Film Keratometry mires which are only clear when the wearer blinks are indicative of a - Steep Fit Keratometry mires which blur immediately following blink are indicative of a - Flat Fit A rigid contact lens shows a flourescein pattern inferiorly and superiorly beneath the lens. This is indicative of which type of astigmatism - With-the-rule A bi-toric rigid lens will show - Two base curves on the radiuscope, sphero-cylindrical rx on the lensometer The ANSI tolerance for a soft lens diameter is - ±0.25 The ANSI tolerance for a soft lens refractive power on a Rx 5.12D to 10.00D - ±0.18 The ANSI tolerance for RGP Base Curve is - ±0.05mm The ANSI tolerance for RGP lens diameter is - ±0.05mm Which instrument allows simultaneous verification of lens diameter, optic zone width, and peripheral curve - Radiuscope Which instrument is best to observe the blends of rigid contact lens - Profile Analyzer If a toric lens rotates to the fitters left - Add the degrees of rotation to the prescribed axis If a toric lens rotates to the fitters right - Subtract (minus) the degrees of rotation to the prescribed axis Increasing the sagittal depth of a rigid lens will - Not change the effective power of the lens How would you stop rotation in a bifocal lens - Truncate the lens Change the base curve Increase prism The DK value of a lens is - Oxygen permeability of that material The original rigid material used in contact lens manufacturing - Polymethylmethacrylate (PMMA) Orthokeratology may be defined as - Reduction of refractive errors by corneal molding with the contact lens applications What can be used to evaluate a dry eye patient - Sodium Flourscein Schirmer Strips Rose Bengal An advantage of a flourocarbon lens is its - High DK value Given an Rx of -4.00 + 0.75 x 90 K readings of 43.50@180/44.25@90 a lens designed on K would have an effective sphere power of - -3.25 (always remember to transpose to minus format) A protein found in the tear film that is a potent germ killer - Lysozyme When trial lens fitting a soft lens patient, after placing the lens on the eye, you should - Allow the lens to settle twenty minutes before evaluating Corneal epithelial edema will appear as - A grey haze, using a slit lamp with sclerotic scatter and the unaided eye Apical flourescein pooling under a rigid lens indicates - A tight fit A dynamic flourescein pattern is best illuminated by - Cobalt blue light An "ideal" flouorescein pattern for a spherical lens on a spherical cornea would show - An even distribution of flourescein with added thickness under the peripheral curves When a rigid contact lens shows apical touch, this would indicate - A flat fit When a spectacle Rx exceeds __________ D, vertex distance must be compensated for when determining the power of a contact lens - ±4.00 Astigmatism that is left over after a contact lens is placed on the eye - Residual Astigmatism Fenestrations are put into a lens to - Increase oxygen transmission When the power of a bifocal gradually changes from the central area of the lens to the periphery, it is called - An aspheric lens A bifocal design that utilizes a small central reading area and a distance periphery is - Reverese Centrad In the manufacturing process, when there is a polished front curve, a polished back curve and a diameter, it is - Semi-finished lens Back toric lens works with - High corneal toricity Single Cut aphakic contact lenses can be well suited for patients with - small apertures and flat corneas In bitoric lens fitting, rotation is controlled by - Relationship of base curve to anterior corneal cylinder The amount of prism ballast often used in ballasted lenses to prevent lens rotation - 1.50D of prism A aspheric PCC - Is a toric pcc and has a specific eccentricity value Diameter of a contact lens can be reduced by: a. razor blade b. cut down stone c. file technique d. all the above - d. all the above Good example of a bifocal contact lens which may rotate without vision impairment is - An aspheric lens