NCLE Exam Questions With Correct Answers

What is the thickest layer of the cornea? - Answer stroma Which corneal layer controls the fluid content of the cornea? - Answer endothelium What is cornea edema? - Answer excess fluid in the stroma that can swell it and lead to loss of visual acuity What kind of contact lenses must be stabilized (not rotate) on the eye for good vision? - Answer toric contact lenses Concentric vs Aspheric Multifocal Lens Design - Answer aspheric multifocal lenses have a gradual change in power from distance to near where as the power change in concentric designs is not gradual eye dominance - Answer the preference of one eye over the other for visual acuity and monocular activity average central corneal curvature - Answer 7.8 mm of radius or 43.25D cornea's index of refraction - Answer 1.376 corneal apex - Answer Central and steepest part of the cornea, 3-5 mm in diameter. (also the only part of the cornea tested during keratometry reading) with-the-rule astigmatism - Answer the vertical corneal meridian has the steepest curvature against-the-rule astigmatism - Answer the horizontal meridian has the steepest curvature Oblique astigmatism - Answer regular astigmatism in which the principal meridians are other than 90 & 180 Irregular astigmatism - Answer The principal meridians are not 90 degrees apart HVID (horizontal visible iris diameter) - Answer measured corneal diameter. average= 11.7 mm Apical Alignment/Lid Attachment - Answer upper lens edge is tucked unter upper eye lid and moves with blinking motion What material is used to evaluate GP lenses under a slit lamp? - Answer fluorescein Increasing saggital depth will... - Answer tighten lens fit How to decrease saggital depth - Answer decrease diameter and/or flatten base curve Lenticular Astigmatism - Answer astigmatism found in the crystalline lens What is neutralization in the lens care system? - Answer neutralizing hydrogen peroxide disinfectant before wear contact lenses on the eye How much NaCl is in the tear film and saline solution? - Answer 0.9% What is used to rinse/wet contact lens rather than tap water? - Answer saline solution How much refractive astigmatism is allowable for spherical SOFT contact lenses? - Answer ~0.75 D or less oxygen transmissibility formula - Answer Dk/t What's the difference between Schirmer's Test 1 and 2? - Answer Test 2 involves stimulatingthe nasal musoca to measure reflex tearing. Sjoren's syndrome - Answer autoimmune disease that causes dry eye. (moisture-producing glands in the body are attacked) A healthy tear break up time is - Answer 10-12 secs Neovascularization - Answer formation of new blood vessels Munson's sign - Answer V-shape of the cornea that indicates Keratoconus Corneal Infiltrates - Answer an accumulation of inflammatory cells (whitish opacity or gray haze) in the stroma CLARE - Answer contact lens associated red eye CLPU - Answer contact lens peripheral ulcer Hydra-PEG - Answer permanent treatment done to GP lenses to increase wettability and minimize deposits plasma treatment - Answer use of oxygen to remove debri from GP lenses after manufacturing Optic Flare - Answer stray light refracted by peripheral curves of contact lens (rather than optic zone) because the edge of the lens is too close to the pupil Where is the tarsal plate? What are they responsible for? - Answer rigid part of eyelid that contains meibomiam glands that secrete lipid layer of tears average pH of tear film - Answer 7.4 bulbar conjunctiva - Answer overlays the eyeball, with the white sclera showing through palpebral conjunctiva - Answer lines the eyelids Deturgescence, Corneal - Answer The state of relative dehydration maintained by the normal intact cornea which enables it to remain transparent 3 and 9 o'clock staining - Answer flourescein pattern in the horizontal margin due to tight lens-to-cornea relationship and poor tear film distribution Myoflange - Answer to increase edge thickness in high plus lenses Hyperflange - Answer Plus lenticulation. to decrease edge thickness in high minus lenses