Contact Lens Registry Examination (CLRE) Practice

These questions are part of the practice quiz. Start practicing

• What is the typical magnification power range available on a slit lamp?
• What type of staining pattern is characterized by a large break or area of erosion?
• What type of astigmatism may be revealed when a rigid contact lens is applied?
• What can cause GPC?
• What term describes a moderate to high refractive difference in powers?
• Dryness-related discomfort in a silicone hydrogel lens can often be mistaken for what condition?
• What instrument is used to determine the power of a rigid contact?
• What tool is primarily used to measure the curvature of the cornea?
• According to the rule of thumb, how much larger should a lens diameter be than the HVID?
• What is the main advantage of using bifocal contact lenses?
• What is the common term for a condition where the cornea has abnormal shape leading to distorted vision?
• What should all eyecare professionals be familiar with in relation to federal laws and regulations?
• What aspect of lens design can affect the lens fit on the cornea?
• What is the pin on the outside of the keratometer designed for?
• What does HIPAA stand for?
• What instrument is best used to measure the curves of the cornea?
• If a patient's refractive cylinder axis is 180 degrees and the lens markings settle 3 minutes to the fitter's left, what axis should you order?
• What lens is typically used on patients with recurrent epithelial erosion?
• What is the process of removing plastic from the bottom of a contact to produce a flat edge to control rotation called?
• Why is it important to measure a patient's K readings when fitting contact lenses?
• Muller provided a "glass shell" lens to treat which condition?
• What astigmatism will cause the square to appear slightly elongated in the vertical meridian when viewed through spectacles?
• What is the visual acuity of an average infant at birth?
• What is the purpose of fluorine in rigid oxygen permeable lenses?
• What role do contact lenses serve in medical applications?
• Which ingredient is key in silicone hydrogel lenses?
• With a spectacle prescription of -3.00 -1.50 x 180 and K readings of 43.50 @180 and 46.50 @ 90, what would be the residual astigmatism?
• What does PRK stand for?
• What is a common symptom of dry eye syndrome that contact lens wearers might experience?
• What is the ideal replacement schedule for daily wear soft contact lenses?
• What unusual device did Otto Wichterle use to produce his first hydrogel lenses?
• What auxiliary power lens would you use to extend the range of the keratometer to 61.00 D?
• High water content in contact lenses can lead to which of the following?
• What is the prismatic effect 2 mm from the optical center of a +7.00 lens?
• What is also known as "lazy eye"?
• What type of lens will need two separate radiuscope measurements for each lens surface?
• What is a characteristic of contact lenses in terms of their manufacturing perspective?
• For what was the material cellulose acetate butyrate originally used?
• What is the astigmatism for the Rx -2.00 -2.50 x 180?
• What is the primary purpose of conducting a follow-up exam after contact lens fitting?
• If a dispenser willfully violates HIPAA that is not corrected, what is the criminal penalty?
• What is another term for the white part of the eye?
• What type of medical condition is exophthalmos often associated with?
• What is the condition characterized by inflammation of the eyelid margin?
• What instrument is used to determine the base curve of a rigid contact?
• What is the inflammation of the lacrimal gland called?
• What is the swelling of the corneal tissue called?
• What does HEMA stand for?
• What is the index of refraction of the tear film?
• What instrument is used to determine a good fit of contacts?
• Which of the following is an iris abnormality?
• In which situation might Dynamic stabilization by Weicon be utilized?
• What illumination is best used to view edge lift of soft lenses?
• What unit of measurement is used with the Chord Diameter?
• Which considerations will help the fitter to best advise a patient?
• What is not an example of non-compliant behavior with contact lenses?
• What is the average visual acuity of a child at 4 months of age?
• Which portion of the edge is in contact with the upper lid during the blink cycle?
• To which index of refraction is the keratometer calibrated?
• What is a secondary curve?
• What were the results of the first experience for potential contact lenses theory performed with a glass tube?
• What is the main reason to fit a Ballasted lens?
• What is the basis material for the second and third generation of silicone hydrogel monomers?
• What is the typical diameter of the corneal cap?
• How much movement do most lens manufacturers recommend for soft lenses?
• Tear deficiencies may lead to which of the following conditions?
• What fitting philosophy is best suited for translating bifocal contact lenses?
• Which structure is responsible for accommodation?
• Which is not a slit lamp illumination?
• How can a flat cornea, even down to 31.00 diopters, be effectively measured?
• What material did Thomas Young use to affix water-filled lenses to his eyes?
• How many extrinsic muscles are attached to each eye?
• How should a contact lens be stored when not in use?
• What is the astigmatism for the Rx -0.50 -4.50 x 90?
• What term describes the absence of the crystalline lens?
• Which company was the first to market soft contact lenses in the United States?
• What is a collection of white blood cells that occur subepithelial?
• Which type of lens material allows more oxygen to reach the cornea?
• What contact lens material was developed in 1979 by Syntex Ophthalmics?
• What does HVID mean?
• What is another name for a lens button?
• What is the typical optical zone diameter of a corneal alignment fit?
• A patient with a spectacle Rx of -1.00 -2.00 x 160 has K readings of 42.50 @160 / 44.50 @ 70. What is the expected power of the contact lens needed if a rigid lens with a back surface radius of 7.94 is placed on the eye?
• How would you express the base curve of 39.50 diopters in millimeters?
• What helps a rigid lens to mask corneal astigmatism?
• What are small refractile lesions that are irregular in shape and can vary in size called?
• What is the best practice when inserting contact lenses on an infant?
• What is the recommended diameter range for soft contact lenses?
• A patient diagnosed with a -2.50 rigid diagnostic lens has an over-refraction of -0.75 -0.25 x 98. What lens power should be ordered?
• What is true of simple hyperopic astigmatism?
• What is the final view seen in the radiuscope before reading the scale?
• What will excessive tilting of a lens cause?
• What is it called when a patient experiences poor vision after removing contact lenses?
• For a patient with astigmatism, what type of contact lens might be prescribed to ensure optimal vision?
• As sagittal depth increases, what happens to vaulting?
• Which is an advantage of rigid gas perm lenses over soft lenses?
• What is defined as an involuntary oscillation of the eyeball?
• What is the effect of increasing the diameter of a contact lens?
• What is the primary purpose of a bandage lens?
• What is the index of refraction for the Aqueous and Vitreous humor?
• What are the layers of the cornea from outside in?
• How much of the information do most people remember?
• What is a disadvantage of using daily contacts?
• Which Base Curve is classified as the flattest?
• The curve on the front surface of a contact lens is referred to as what?
• What is HEMA primarily known for in the context of contact lenses?
• What does it mean if a lens is fit "on K"?
• What is a common consequence of an enlarged thyroid gland?
• What distance is generally considered to be optical infinity?
• What are the color representations on the typical topographic map?
• What are the layers of the cornea from inside out?
• How many types of regular astigmatism are recognized?
• Which of the following is a common complication in contact lens wearers leading to discomfort?
• What is the primary function of the digital corneal topographer?
• A toric contact lens is specifically used to correct which refractive error?
• What is a way to test to see if a lens is inverted?
• What is the index of refraction of the cornea?
• What are the layers of the tear film from outside in?
• What is the most common removal method for a soft contact lens?
• A patient with an Rx of +2.50 + 0.50 x 180 fit .50 flatter than K would need a contact with what power?
• Which of the following is a property of Silicone-Acrylate lenses?
• When fitting a patient with a Spectacle Rx -4.00 -1.25 x 80 A diagnostic soft contact lens of -4.00 - 1.25 x 90 rotates clockwise 10 degrees. What axis should be ordered?
• When fitting with a rigid gas permeable contact what is a good diameter to start with?
• What condition is most likely to be treated with a scleral lens?
• What type of abnormal growth can invade the cornea?
• What is made of fibrous connective tissue that forms the supporting structure of the eyelid?
• How long should a soft lens settle on the eye before fitting evaluation?
• What is the non-inflammatory eye condition in which the cornea steepens and thins?
• Which lens type is specifically designed to be worn over an existing contact lens?
• Which of the following was a drawback of CAB lenses?
• What is the usual truncation size for a contact lens?
• At what power do you make adjustments for vertex distance?
• What are the overall external ocular structures known as?
• In about 1888, who corrected his own myopia with a glass-blown contact lens?
• What is not a sign of hypoxia?
• What should the edge thickness of rigid gas permeable lenses generally be?
• Which test is best used for determining the quality of a patient's tears?
• What characteristic do higher Dk materials provide compared to lower Dk materials for contact lenses?
• What is the name of a special contact lens used to treat keratoconus, featuring a soft outer lens and a rigid center?
• What astigmatism is characterized by a 43.00 @180/44.00 @090?
• Leonardo DaVinci's concept of neutralizing the cornea included the use of what substance?
• A patient who is typically fit with contact lenses may experience which of the following advantages?
• How many transitional zones does a quadcurve lens typically have?
• K readings in contact lens fitting are primarily based on which measurement?
• What is the index of refraction for the Vitreous humor?
• What is a key advantage of using HEMA in contact lenses?
• What is the most common removal method of a gas perm lens?
• What term refers to the amount of oxygen that passes through a lens material of specific thickness?
• What is the most common material used for soft contact lenses?
• What is a hallmark of principal meridians?
• What does SMA stand for?
• What is a possible reason that a teenager may want contact lenses?
• Which gas permeable lens material was approved by the FDA in 1979?
• What is a common cause of discomfort with contact lenses?
• What is the total diameter of a bicurve lens with an 8.5 mm base curve and a 1.2 mm peripheral curve?
• What type of vision correction does monovision contact lens fitting provide?
• What is an abnormal symptom of contact lens wear?
• Which profession is a contraindication for contact lenses?
• What is typically a characteristic of soft lenses compared to rigid lenses?
• What is a plastic polymer?
• When should the first follow-up appointment be scheduled after moving to an extended wear contact lens?
• What is the drooping of the upper lid called?
• What material was used for contact lenses before 1930?
• What is an early sign of keratoconus?
• How should scleral lenses be inserted?
• What is the index of refraction of glass if light travels through the glass at a speed of 133,000 mi/sec?
• What effect does prism have on the position of a lens on the eye?
• When compared to a normal image size, an aphakic person will view the same image as ________ larger through contacts.
• Which lens modification can be performed in an office setting?
• What fitting method is best used for a patient with Keratoconus?
• Which Base Curve is considered to be the steepest?
• What type of contact lens has a primary base curve and a peripheral curve?
• What development led to a design for soft toric contact lenses?
• If a soft toric lens is too tight:
• If a patient's K reading shows the same diopter value at 180 and 90, what type of lens will be needed?
• What type of contact lens is designed to correct both spherical error and astigmatism?
• A patient fit with a 44.00D lens and a power of -2.00 is re-fit with a base curve of 44.50. What power will now be required?
• What is an example of an age-related sign of presbyopia?
• What would be a good reason to avoid using a HEMA lens?
• What could be a valid reason to deny fitting a patient with contact lenses?
• What element is assessed using K Reading during a contact lens fitting?
• What type of material is used in hydrogel contact lenses?
• Where should scleral lenses be placed for proper fitting?
• What is the most common design for both gas perm and rigid lenses?
• In SOAP documentation, what does the "A" stand for?
• Which illumination is useful for viewing neovascularization?
• What is the spherical equivalence of the Rx -2.75 -1.00 x 180?
• Why might a patient mistakenly believe they have an allergy after wearing a silicone hydrogel lens?
• What measurement is typically taken using a V-gauge?
• What is the primary risk of moist-heat sterilization in contact lens care?
• What is another name for eyelids?
• What fitting choice involved fitting a distance contact over the dominant eye and a reading contact lens over the non-dominant eye?
• Where can one find the chemical make-up of a hydrogel lens?
• What do you see when the keratometer is out of focus on the cornea?
• Which is an example of against-the-rule astigmatism?
• What color filter is helpful when observing areas of vascularization on the cornea?
• What is true about a contact lens prescription?
• Which condition is best treated with plus power lenses?
• What is a chronic, auto-immune disorder characterized by monocular cell infiltration of the lacrimal and salivary glands?
• How are contact lenses classified?
• What instrument is best used to observe contact lens rotation?
• What is the chord length of the mire measured by the keratometer without an auxiliary lens?
• Which of the following is not a primary type of bifocal contact lens?
• Which material is preferred for gas permeable contact lenses for optimal oxygen transmission?
• What characteristic should a well-fitted soft contact lens have during blinking?
• What might a patient fitted with a -6.00 rigid diagnostic lens experience?
• How often should the eyepiece of a keratometer be focused?
• What is the conversion of 43 diopters to millimeters?
• How much Corneal Astigmatism does a patient have when they have K readings of 42.25 and 43.75?
• What is the axial length of the human eye at birth?
• What does LARS stand for?
• What challenge did early soft contact lenses face due to material properties?
• Which of the drugs can cause a reduced blink rate?
• In the order of operations, what comes before multiplication?
• What is a primary reason for choosing a higher DK fluorocarbon material over soft hydrogel?