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A comprehensive set of practice questions and answers related to the ncle exam, focusing on contact lens fitting and corneal anatomy. It covers various aspects of contact lens fitting, including astigmatism, lens rotation, keratoconus, presbyopia, and tear film dynamics. The document also includes questions about the structure and function of the cornea, its layers, and its nutrient supply. This resource is valuable for students preparing for the ncle exam, as it provides a comprehensive overview of key concepts and practical applications.
Typology: Exams
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With a rigid contact lens in place a flourescein pattern shows a narrow bend horizontally wih a concentration of flourescein inferiorly and superiorly under the lens. Which one of the following type of astigmatism is represented by this pattern? a. lenticular astigmatism b. residual astigmatism c. against the rule astigmatism d. with the rule astigmatism - ANSWER--d. with the rule astigmatism Refractive Rx - 3.00 - 1.00 x 170 K's 42.00 @ 170/43.00 @ 80 Given the above Rx and K's he following diagnostic toric soft lens was used: B.C. 8. Power - 3.00 - 1.00 x 180 During dianostic evalutation, the above lens rotated 10 clockwise. The lens ordered should have an axis of: a. 10 b. 180 c. 170 d. 160 - ANSWER--b. 180
Given the same circumstances from the above question, once the correctly ordered lens has been dispensed, the rotational marks should settle at _______. a. 6 o clock b. 10 clockwise rotation c. 10 counter clockwise rotation d. none of the above - ANSWER--b. 10 clockwise rotation An instrument that allows simultaneous verification of lens diameter, optic zone width, and peripheral curve width is: a. measuring magnifier b. ophthalmometer c. profile analyzer d. radiuscope - ANSWER--a. measuring magnifier (the book says d. radiuscope) The instrument used for magnification of the edge of a rigid CL is a _______. a. radiuscope b. shadowgraph c. profile analysis
d. keratometer - ANSWER--b. shadowgraph Mary is wearing in her right eye RGP lens with a base curve of 43. and a power of +2.75. The doctor refracts - 0.75 sphere over this lens. If you wish to order her a new lens with a curve of 43.00, what will the new power be? a. +1. b. +2. c. +2. d. +3.00 - ANSWER--c. + Which of the following could be considered in the fitting of a keratoconus patient
Two designs helpful in orienting high riding myopic lenses are:
c. 2 & 4 d. all of the above - ANSWER--d. all of the above A good example of a bifocal contact lens which may rotate without vision imparement is: a. aspheric b. executive c. fused crescent d. tangent streak - ANSWER--d. tangent streak Keratoconus and penetrating keratoplasty fittings are best accomplished by which of the following methods? a. nomogram b. Ks and Rx c. diagnostic fitting d. molded impression - ANSWER--c. diagnostic fitting Given the following information: K's 45.00/44.00 @ 90 Rx - 3.00 + 1.00 x 180
Which of the following set of lens specifications would most simulate an intrapalpebral RGP fitting? B.C Rx Dia. a. 44.50 - 2.50 8. b. 43.50 - 1.50 8. c. 43.50 - 1.50 9. d. 44.50 - 2.50 9.5 - ANSWER--B.C Rx Dia. a. 44.50 - 2.50 8. (NUMBER 22) Given the following information: K's 45.00 @ 180/42.00 @ 90 Rx - 2.00 - 4.25 x 90 Which of the following RGP lens designs would best correct this wearers vision? a. 45.00 - 2. b. 42.00 - 2.00 - 4.25 x 90 prism ballasted c. 42.00 - 2. d. 42.00/45.00 - 2.00 - ANSWER--d. 42.00/45.00 - 2.
A _________ lens is a translating bifocal: a. concentric b. aspheric c. deffractive d. segmented - ANSWER--d. segmented Given the following information: K's 42.50@180/42.50@ Rx - 3.00-1.00@ Which of the following set of RGP lens specifications will best correct this wearers vision? a. 42.50/43.50 - 3.00-1.00x b. 42.50 - 3.00-1.00x90 prism ballasted c. 42.50 - 3. d. 43.00 - 3.50 - ANSWER--b. 42.50 - 3.00-1.00x90 prism ballasted Given the following information: K's 42.00@180/45.00@ Rx - 3.00-2.25x Which of the following set of RGP lens specifications will best correct this wearers vision?
a. 42.00/45.00 - 3.00-2. 25 b. 42.00 - 3.00-2.75 x 177 prism ballasted c. 42.00 - 3. d. 45.00 - 3.00 - ANSWER--a. 42.00/45.00 - 3.00-2. A warped lens will show___________ base curve(s) on the radiuscope and a ________ power on the lensometer. a. one/spherical b. two/sphero-cylindrical c. one/sphero-cylindrical d. two/spherical - ANSWER--d. two/spherical The pre-corneal tear film is composed of three distinct layers. They are: a. Lysozyme, oil, lacrimal b. Sebacious, mucoid, BAK c. lipid, lacrimal, mucin d. water, mucoid, lysozyme - ANSWER--c. lipid, lacrimal, mucin The pre-corneal tear film provides
a. Epithelium, Descemets membrane, Stroma, Bowmans membrane, Endothelium. b. Endothelium, Stroma, Bowmans membrane, Descemets membrane, Epithelium. c. Epithelium, Bowmans membrane, Stroma, Descemets membrane, Endothelium. d. Endothelium, Bowmans membrane, Stroma, Descemets membrane, Epithelium. - ANSWER--c. Epithelium, Bowmans membrane, Stroma, Descemets membrane, Endothelium. The normal cornea is transparent due to the pump action creating proper fluid balance. Which layer of the cornea is most responsible for maintaining this function? a. Endothelium b. Basal membrane c. Epithelium d. Bowmans membrane - ANSWER--a. Endothelium
The normal cornea is in a state of a. Turgesence b. Deturgesence c. Hyperemia d. Hypoxia - ANSWER--b. Deturgesence The cornea receives nutrients from 1 Aqueous humor 2 Tears 3 Limbal blood vessels 4 Orbicularis occuli a. 1, 3 & 4 b. 2 & 3 c. 1, 2 & 3 d. 3 & 4 - ANSWER--c. 1, 2 & 3 Refraction - 1.00-3.00 x 90 K Reading 44.00@180/ 41.00@
a. BC 41.00/44.00 Power - 1.00/3. b. BC 41.00/44.00 Power - 1.00/-4. c. BC 41.00/44.00 Power - 4.00/-1. d. BC 44.00/41.00 Power - 1.00/-3.00 - ANSWER--b. BC 41.00/44. Power - 1.00/-4. book lists C as answer? A dense white appearance of the entire peripheral circumference of the cornea which does not stain and is often seen in the elderly is known as: a. neovascularization b. Dellen c. Arcus senilus d. Corneal ulcer - ANSWER--c. Arcus senilus The main focusing mechanism of the eye is the a. Cornea b. Crystalline Lens c. Retina d. Vitreous - ANSWER--b. Crystalline Lens
A normal tear break up time is a. 6-7 seconds b. 10-12 seconds c. Less than 5 seconds d. none of the above - ANSWER--b. 10-12 seconds Which of the following materials will not require a weekly enzymatic cleaner? a. Polymethylmethacrylate lenses b. Sofperm c. Hydroxyethyl Methacrylate lenses d. Silicone - acrylate lenses - ANSWER--a. Polymethylmethacrylate lenses Clinical management of RGP flexure may be eliminated by: a. redicing sagittal vaulting b. increasing center thickness c. Choosing a lower DK material
d. all the above - ANSWER--d. all the above Upon removal of the crystalline lens, the patient is: a. aphakic b. myopic c. hyperopic d. astigmatic - ANSWER--a. aphakic a hardening of the crystalline lens causing loss of accommodation is known as: a. presbyopia b. myopia c. hyperopia d. aphakia - ANSWER--a. presbyopia A rigid contact lens measures +15.00 BVP. The FVP will measure. a. a lesser dioptric reading b. a greater dioptric reading c. an identical dioptric reading d. an astigmatic reading - ANSWER--a. a lesser dioptric reading
Which of the following will not measure lens parameters a. Keratometer b. Radiuscope c. Burton lamp d. Thickness gauge - ANSWER--c. Burton lamp A low riding high plus on a 40.00/40.75 cornea could be corrected with a. a myoflange b. a hyperflange c. a one cut d. a panafocal - ANSWER--a. a myoflange The following ametropia frequently results in high riding rigid lenses a. high myopia b. high hyperopia c. aphakia
d. presbyopia - ANSWER--a. high myopia Corneal deturgescence is maintained by the "pump action" of the ___________ layer a. Endothelial b. Stromal c. Descemet d. Bowman - ANSWER--a. Endothelial Which of the following could cause a patient's rigid contact lens to displace frequently and pop out without cause? 1 excessive posterior peripheral curve 2 insufficient peripheral curve 3 steep base curve relationship 4 flat base curve relationship a. 1 & 4 b. 2 & 3 c. 1 only
d. 2 & 4 - ANSWER--a. 1 & 4 Which of the following preservatives has a low incidence of ocular sensitivity with a soft contact lenses? a. Sorbic Acid b. Chlorobutanol c. Benzalkonium Chloride d. Hydrogen Peroxide 3% - ANSWER--a. Sorbic Acid The following Rx represents: OD= +2.00 = 20/ OS= - 3.00-2.00 x 180 = 20/ a. Presbyopia b. Anisometropia c. Amblyopia d. Emmetropia - ANSWER--b. Anisometropia The above patient will best achieve stereopsis with which following correction?
a. Contact lenses b. Spectacles c. IOL d. Scleral lenses - ANSWER--a. Contact lenses A soft lens has edge lift when observed on a cornea. How can this be corrected? a. Steepen base curve b. Decrease diameter c. Flatten base curve d. Change edge design - ANSWER--a. Steepen base curve A back toric soft lens works best with: a. Residual astigmatism b. High corneal toricity c. Low corneal toricity d. Spherical toricity - ANSWER--b. High corneal toricity
Corneal edema is observed inferiorly under a prism ballast toric soft lens. What is the probable cause? a. Lens is too tight b. Oxygen demand for this cornea is too great c. Lens is too loose d. Prism thickness - ANSWER--d. Prism thickness In evaluating a soft lens fit with either keratometry mires or retinoscopic reflex, you detect distortion immediately after the blink. This is caused by: a. A steep fitting lens b. A properly fitting lens c. A flat fitting lens d. A tight fitting lens - ANSWER--c. A flat fitting lens A non-wetting RGP lens may cause: a. hazy, filmy vision b. lens awareness
c. dryness or grittiness d. all of the above - ANSWER--d. all of the above Causes of lens flexure may include: 1 pressure exerted by the upper lid 2 lens material 3 apical clearance lens design 4 against the rule corneal toricity a. 1 and 3 b. 2 and 4 c. 2 only d. all of the above - ANSWER--d. all of the above The FDA has recommended that extended wear contact lenses be worn for a maximum of: a. 7 days b. 14 days c. 30 days d. 45 days - ANSWER--a. 7 days
Therapeutic soft lenses should be fit with minimal movement in which case? a. Keratitis sicca b. Trichiasis c. Recurrent erosion d. Keratoconus - ANSWER--c. Recurrent erosion An aphakic patient with K readings of 40.50 @ 180/41.25 @ 90, large palpebral fissures and flaccid lower lids is a good candidate for a. a one cut b. a myoflange lenticular c. a hyperflange lenticular d. a back toric - ANSWER--b. a myoflange lenticular The CPC of a rigid lens was ordered 7.84mm and was received measuring 7.94mm. This lens is _____ than ordered. a. 0.50D steeper
b. 1.00D flatter c. 0.50 flatter d. 1.00D steeper - ANSWER--c. 0.50 flatter When evaluating fluorescein patterns, a special filter must be used with __________. a. Silicone acrylate b. Polymethylmethacrylate c. Fluropolymers d. Hydroxyethyl methacrylate - ANSWER--c. Fluropolymers When comparing high DK silicone acrylate polymers to earlier generation materials of the same type, the new "improved" silicone acrylates 1 increase oxygen permeability 2 flex less 3 have poorer wetting characteristics 4 scratch less
a. 1 only b. 1 and 3 c. 2 and 4 d. all are correct - ANSWER--b. 1 and 3 A normal fitting soft contact lens will have: a. three point touch (apex and periphery) b. apical clearance c. edge stand-off d. none of the above - ANSWER--a. three point touch (apex and periphery) The keratometer is an instrument used to measure a. Corneal curvature b. Lens power c. Lens diameter d. Lens thickness - ANSWER--a. Corneal curvature A lens fitted for keratoconus should:
a. Flatten the apex b. Ride high c. Align the apex d. Ride low - ANSWER--c. Align the apex A soft contact lens which is too loose can show all the following EXCEPT: a. edge stand-off b. limbal compression c. a bubble under the lens edge d. clear retinoscopy directly after blinking - ANSWER--b. limbal compression Correction of a high riding rigid minus lens is accomplished by using a a. Flatter lens b. Larger lens c. Minus carrier lenticular lens d. Prism lens - ANSWER--d. Prism lens
Advantages of a myo-flange vs single cut high plus lens unclude 1 reduced center thickness 2 increased optical zone 3 reduced weight a. 1 only b. 1 and 3 c. 2 and 3 d. 1, 2 and 3 - ANSWER--d. 1, 2 and 3 To increase tear exchange on an RGP lens, all of the following can be done EXCEPT: a. reduce the overall lens diameter b. flatten the peripheral curves c. increase the sagittal depth d. decrease the optic zone - ANSWER--c. increase the sagittal depth The average ph value of the human tear is