NCLE Practice Test Practical Questions With Correct Answers

Steep Fluorescein Pattern - Answer Bright green pooling center, very faint green pooling on diameter of lens Flat Fluorescein Pattern - Answer Bright green pooling on diameter of lens, very faint green in center Against-the-rule Astigmatism Pattern - Answer Bright green pooling horizontally, faint green pooling vertically With-the-rule Astigmatism Pattern - Answer Bright green pooling vertically, faint green pooling horizontally Prism Ballast - Answer Common technique to stabilize lens from rotating. Added thickness will position lens inferiorly (bottom of cornea) Truncation - Answer Cutting off .50mm to 1.50mm of bottom edge of lens to provide stability. Reduces diameter, making a looser fit. Double Slab-off - Answer 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 - Answer Hyperflange - Answer Used to correct high riding minus lenses. Myoflange - Answer Used to correct low riding plus lenses. Monovision - Answer Corrects presbyopia in contact wearers. One eye uses distance (dominant) and the other eye uses reading (resessive) Segment Bifocal - Answer Same concept as spectacle bifocal. Must be prism ballast. Often crescent shaped. Toric Lenses - Answer Anterior (front surface), back spherical surface or posterior (back surface), toric back curve Front Toric Lens - Answer Corrects a low to moderate amount of corneal astigmatism Back Toric Lens - Answer Corrects a mid to high amount of corneal astigmatism Bitoric Lens - Answer Corrects 1.50D of corneal astigmatism and high residual astigmatism Aphakic - Answer Condition of no crystalline lens Psuedophakic - Answer Implant, intraocular lens Corneal Edema - Answer Always causes a poor fitting lens Spectacle Blur - Answer Temporary blurred vision upon switching from contact lenses to eyeglasses Crystalline Lens - Answer The main focusing mechanism of the eye The Main Supply of Oxygen to the cornea is provided by - Answer Tear Film Keratometry mires which are only clear when the wearer blinks are indicative of a - Answer Steep Fit Keratometry mires which blur immediately following blink are indicative of a - Answer Flat Fit A rigid contact lens shows a flourescein pattern inferiorly and superiorly beneath the lens. This is indicative of which type of astigmatism - Answer With-the-rule A bi-toric rigid lens will show - Answer Two base curves on the radiuscope, sphero-cylindrical rx on the lensometer The ANSI tolerance for a soft lens diameter is - Answer ±0.25 The ANSI tolerance for a soft lens refractive power on a Rx 5.12D to 10.00D - Answer ±0.18 The ANSI tolerance for RGP Base Curve is - Answer ±0.05mm The ANSI tolerance for RGP lens diameter is - Answer ±0.05mm Which instrument allows simultaneous verification of lens diameter, optic zone width, and peripheral curve - Answer Radiuscope Which instrument is best to observe the blends of rigid contact lens - Answer Profile Analyzer If a toric lens rotates to the fitters left - Answer Add the degrees of rotation to the prescribed axis If a toric lens rotates to the fitters right - Answer Subtract (minus) the degrees of rotation to the prescribed axis Increasing the sagittal depth of a rigid lens will - Answer Not change the effective power of the lens How would you stop rotation in a bifocal lens - Answer Truncate the lens Change the base curve Increase prism The DK value of a lens is - Answer Oxygen permeability of that material The original rigid material used in contact lens manufacturing - Answer Polymethylmethacrylate (PMMA)