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Contact Lens Final
final exam questions
| Question | Answer |
|---|---|
| The goblet cells that secrete mucous into the tear film are located in which structure? | conjunctiva |
| The transition zone between the bulbar conjunctiva and the palpebral conjunctiva is called the: | fornix |
| The condition where one eye is turned is called? | strabismus |
| **Which of the following conditions is a contraindication to contact lens wear? A. severe blepharitis B. keratoconus C. bullous keratopathy D. irregular astigmatism | A. severe blepharitis |
| **Which of the following patients will experience the most image magnification? A. myope wearing spectacles B. myope wearing contacts C. hyperope wearing spectacles D. hyperope wearing contacts | C. hyperope wearing spectacles |
| **the preferred method of vision correction in keratoconus is: | rigid contact lenses |
| the eyelid muscle for responsible for closure of the lids is the: | orbicularis oculi |
| the limiting margin of the apex: | can be found by topographical keratometry |
| **the normal blink rate is approximately ____ times per minute. | 12 f |
| Tear/ aqueous fluid is secreted by the _________ glands. | lacrimal |
| The average pH value of the human tear is: | 7.4 |
| The corneal layer that consists of a single layer of hexagonal cells is the | endothelium |
| The lipid layer is secreted by _____ and ____ glands. | meibomian/zeis |
| the mucoid layer is secreted by the | goblet cells |
| which layer of the tear film is the thickest? | tear/aqueous |
| loss of accommodative ability is : A. ciliary muscle B. crystalline lens C. zonular fibers D. All of the above | D. all of the above |
| how many extrinsic muscles are attached to each eye? | six |
| how much oxygen does the cornea get during sleep? | 7% |
| pupillary constriction is called | miosis |
| stereopsis can only occur with | binocular vision |
| The additive primary colors are | red, green, and blue |
| the bony orbit of the eye is most shaped like a | pyramid |
| the fovea centralis of the retina contains | only rods |
| the levator superioris muscle | raises the upper lid |
| the bacteriocidal ingredient found in the precorneal tear film is | lysozyme |
| the epithelium comprises ____% of the corneal thickness | 10% |
| Through strong aphakic spectacles, a patient will see an object _______ larger compared to the normal image size. | 33% |
| Rays of light striking a spectacle lens at its edge creat ______ or distortions | aberrations |
| _______ is a moderate to high refractive difference in the powers of the two eyes. | anisometropia |
| Through spectacles, the astigmatic patient with "against-the-rule" astigmatism will view a square as follows: | the square will appear slightly elongated in the vertical meridian |
| The visual error caused by a cylindrical crystalline lens is known as _______ astigmatism | lenticular |
| the practitioner should suspect _________ astigmatism if there is a difference between the amount of cylinder found by keratometry readings and the amount of cylinder found by refractometry | internal |
| when myopic patients view an object at near through their spectacles, the prism created through the spectacles is _____ | base in |
| a ______ person must accommodate more when viewing near objects through their contact lenses vs. spectacles | myopic |
| _____ _______ results when the cornea has been damaged by trauma, inflammation or scar tissue | irregular astigmatism |
| objects in the field of vision of a high myope are ______ when spectacles are worn | minified |
| __________ is a developmental anomaly of the cornea that results in irregular myopic astigmatism | keratoconus |
| when decomposition of the __________ occurs, aqueous humor leaks into the anterior layers of the cornea forming bullae | endothelium |
| in the latter stages of keratoconus, the following may be observed: A. Munson's sign B. distorted mires C. corneal opacities D. Fleischer's ring E. All of the above | E. All of the above |
| _________ lenses are used on patients with recurring endothelial erosions | bandage |
| fitting a rigid contact lens steeper than the flattest corneal meridian will introduce _____ _________ power into the lacrimal lens | plus sphere |
| for patients with a moderate amount of corneal astigmatism (between 1 and 2 diopters), which lens type will provide the crispest, most stable vision | rigid spherical |
| __________ _______ predisposes the eye to drying due to proptosis | thyroid disease |
| _______ _________ usually causes photophobia, itching, lacrimation, and burning | respiratory allergies |
| _______ is a systemic drug used in the treatment of acne | acutane |
| _________ may cause blurred vision due to its direct action on accommodation | Donnatal |
| ________ _________causes changes in the fluid balance of the body | endocrine changes |
| in the making of concentric style bifocals, the different power zones may be ground on _______ __________ | either surface |
| the addition of fluorine to gas permeable lens ingredients increases | wettability |
| which of the following instruments would not be used to verify the lens diameter in the office? A. diameter gauge B. radiuscope C. measuring magnifier D. projection magnifier | B. radiuscope |
| measuring the lens blank in lathe so that the face of the button is perpendicular to the spindle is necessary to avoid | unwanted prism |
| when reading the radius of curvature of the back surface of a contact lens with the radiuscope, the lens is floated on a drop of liquid to | neutralize the reflection from the front of the lens surface |
| during the lathing process for toric lenses, the cylinder power is generated by | squeezing the lens in a crimping tool |
| when the lens power is verified, placing the concave surface against the lens meter aperture will reveal | back vertex power |
| which of the following polishes should not be used to polish gas permeable lenses? A. silvo B. silvo O2 care C. alox D. X-pal | A. silvo |
| after reducing the overall diameter, which of the following additional modifications are not required? A. applying peripheral curves B. blending C. edge shaping and polsishing D. Changing the base curve | D. changing the base curve |
| removal of plastic from the bottom of a lens to produce a flat edge that will control rotation is called: | truncation |
| in-office power changes should be limited to +/- ____ D or less | 0.50 |
| when gas permeable lenses are manufactured, which parameter is cut first? | central poserior curve |
| after the sharp junction between curves on the lens posterior are smoothed out, they are called | blends |
| which in-office modification is the easiest to perform? | adding minus power |
| calculation of which lens parameter is not under the control of the fitter? | anterior power curve |
| polishing the surfaces of rigid gas permeable lenses should be performed | only when it is needed |
| lens blends and ski edge can be verified using a | long fluorescent light bulb |
| an in-office modification that can be done to thin the edge of a minus lens is the | CN bevel |
| the ideal finished edge thickness for rigid lenses, regardless of whether they are plus or minus is ______ mm | 0.08-0.12 |
| in aspheric lens design, the change in curvature that occurs from the center to the edge of the aspheric zone is called | eccentricity |
| hydrogel lens materials allow the transport of oxygen to the cornea and carbon dioxide away from the cornea because they contain | water bound to reactive sites |
| the FDA has created 5 lens groups to clarify categories of similar hydrophilic lens polymers. These groups are defined by: | water content, electrostatic, and material properties |
| the chemical make-up of hydrogel lens materials is listed in the | package insert |
| during the lathe cutting process, humidity must be controlled at a low level in order to | avoid destruction of the lens |
| a spin-cast will generate | an aspheric back surface |
| the lens stabilization system most often used to prevent or control rotation or control or toric soft lenses is | prism ballast |
| the term GMP is the acronym for | good manufacturing practices |
| hydrogel buttons used in manufacturing are tested and quarantined until they are documented | to meet all approved standards |
| which of the following hydrogel parameters can be readily verified in the office? | power |
| which of the following hydrogel lens parameters may be modified in the practitioner's office? A. base curve B. power C. diameter D. none of the above. | D. none of the above |
| functions of the eyelids that are important to contact lens wear | prevents evaporation, helps position contacts, spreads tears over cornea, and removes debris from cornea |
| the boundary between the conjunctiva that covers the sclera and the cornea is called the | limbal margin |
| an internal swelling in the meibomian gland of the eyelid is called | chalazion |
| what are three classifications of contact lenses according to size or the area they cover? | scleral, corneal, and semi-scleral |
| the state of relative dehydration maintained by the normal intact cornea that enables the cornea to remain transparent | deturgescence |
| why do we put peripheral curves on the posterior surface of most contact lenses today? | to better fit the corneal shape and to increase comfort and to allow proper tear exchange under the lens |
| There is an area along the midline called the gray line. What lid structure does this identify and what is its purpose? | tarsal plate-to provide rigidity to the eyelid |
| The cornea must maintain proper water content of ____% | 78 |
| which layer maintains a fixed shape so the cornea can function optically? | Bowman's layer |
| There are 2 factors that aid in the prevention of corneal infection, one is an antibacterial agent called ________ and the other is the cornea's lower ____________. | lysozyme; temperature |
| the conjunctiva lining the upper and lower lids is called the | palpebral conjunctiva |
| how much oxygen does the cornea get when we sleep? | 7-8% |
| what is the minimum amount of oxygen at which the cornea can function? | 3-4% |
| the cornea receives nutrients from _______, _________, and _________ | aqueous humor, tears, and limbal blood vessels |
| which layer of the cornea makes up 10% of the structure's total thickness? | epitherlium |
| a 0.9% saline solution would be | isotonic to the eye |
| a contact lens that covers both the cornea and sclera would be considered a | scleral lens |
| aqueous humor is secreted by the | ciliary body |
| inflammation of the lacrimal gland | dacryoadenitis |
| incomplete eyelid closure | lagophthalmos |
| infection of a zeis gland | hordeolum |
| a small, flat, pigmented benign tumor | nevus |
| a wedge-shaped overgrowth on the medial bulbar conjunctiva | pterygium |
| tears spilling out onto cheeks due to faulty drainage | epiphora |
| inward turning of the eyelashes | trichiasis |
| a viral infection affecting the conjunctiva, producing severe scarring of the lids and eventually affecting the cornea | trachoma |
| a small, rounded, yellowish, benign tumor | pinguecula |
| inflammation of the lacrimal sac | dacryocystitis |
| the function of the peripheral curve is to | allows to clear the flatter periphery of the cornea and to prevent lens impingement in the limbal area as the lens moves with the blink |
| the fovea centralis of the retina contains | only cones |
| movement of the eye upward | elevation |
| movement of the eye downward | depression |
| movement of the eye medially, or inward toward the nose, from the straight ahead position | adduction |
| rotation of the twelve o'clock position of the cornea downward and outward | intorsion |
| movement of the eye laterally, or outward | abduction |
| rotation of the twelve o'clock position of the cornea downward and outward | extorsion |
| which is the steepest curve IPC or PPC? | IPC |
| this would be a test of tears quality | TBUT test |
| the goblet cells that secrete mucous into the tear film are located in which structure? | conjunctiva |
| the sphincter muscle of the eyelid, the contraction of this muscle closes the eyelid | orbicularis oculi |
| the anterior cornea's main source of oxygen is the | atmosphere |
| the anterior ciliary arteries terminate at the | limbus |
| which surface do we refer to as the base curve? | central posterior curve |
| the quantity of the tears is measured by the | schirmer's test |
| what is keratoconjunctivitis sicca(KCS)? | dry eye syndrome, a condition in which there is insufficient tears |
| swelling of the corneal tissue, or any tissue is called | edema |
| the base curve of a contact lens, CPC, is designed to conform to the optic zone of the | cornea |
| the practitioner should suspect ______ astigmatism if there is a difference between the amount of cylinder found by keratometry readings and the amount of cylinder found by refractometry | internal |
| which hobby or occupations are advised to blink often and look off into the distance on occasion? | needle point |
| what is the sagittal depth of a lens? | the distance between the posterior surface of the central area of the lens and flat surface |
Created by:
celticdragon86