NCLE Practice Exam Questions with Correct Answers

NCLE Practice 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