NCLE Basic Certification Practice Exam

These questions are part of the practice quiz. Start practicing

• What is referred to as the sagittal depth of a lens?
• What is the primary source of oxygen that the cornea receives?
• What type of illumination is primarily used for viewing the edge light of soft contact lenses?
• What happens to the stroma if the endothelium fails to perform its pumping function?
• What does the term 'dimple veiling' refer to in contact lenses?
• If all mires are out of focus on a radioscope verification, what is likely true about the lens?
• What effect does steepening the posterior curve of a contact lens have?
• How many diopters does a prism ballast typically use to prevent excessive lens rotation?
• Which cleaning method is most likely to shorten the lifespan of contact lenses?
• What is the effective method for removing protein from a gas permeable lens?
• What is a key characteristic of gas permeable contact lenses?
• To increase tear exchange on a RGP lens, which action is recommended?
• What impact does a dehydrated contact lens have on inferior arcuate lesion staining?
• What is the purpose of a red chrome contact lens?
• What can cause epithelial damage regarding hydrogen peroxide cleaning solutions?
• What is a myoflange designed to prevent in contact lens fitting?
• To evaluate the transitional zone between the optic zone and the lens edge, which tool is most appropriate?
• In a case of high astigmatism fitted with a spherical RGP, where will the lens typically show touch?
• What is the primary indication of a steep fitting contact lens?
• Which two methods are used for stabilization of rigid gas permeable (RGP) lenses?
• Which preservative is known to be mercury-based?
• What role does chlorobutanol play in contact lens solutions?
• How long should a wearer rub the lens when using a multipurpose solution?
• What type of illumination focuses a beam of light and microscope directly on the image being examined?
• How often should surfactant cleaner be used after contact lens removal?
• What is a characteristic of bifocal lens designs?
• In terms of keratometry, what does a loose fitting lens indicate about the appearance of the mires?
• What must be included with a hydrogen peroxide cleaning system to ensure it works correctly?
• If a soft contact lens wearer experiences burning as the day progresses, what does this usually indicate?
• What type of illumination is mainly used to detect corneal edema?
• If a soft contact lens gets stuck to the cornea, what should you do?
• Which device uses concentric circles to assess the corneal surface quality?
• What might a contact lens patient experience if they do not soak their lenses in a hydrogen peroxide cleaning system for the required duration?
• What condition is likely to result in a high riding lens?
• When wearing a soft spherical contact lens with mild corneal astigmatism, which type of lens masks astigmatism more effectively?
• What observable effect indicates that a keratometer is out of focus on the cornea?
• Which type of lenses are gas permeable lenses?
• What is a potential indication that a foreign body is trapped in a contact lens wearer’s eye?
• What should never be used to irrigate the eye when a soft contact lens gets stuck?
• What is the primary function of mucin in the tear film?
• What is the result of increasing total diameter on a contact lens?
• What is an alternative use for the keratometer in optometry?
• What does a keratometer reading exceeding 0.50D indicate?
• What change should be made to increase lens movement on a contact lens?
• In which location are the openings of the meibomian glands found?
• What is the purpose of a wetting solution in contact lenses?
• What technique is employed to correct high riding gas permeable minus lenses?
• How long does it typically take to adapt to wearing soft contact lenses?
• What purpose does a minus lenticular design serve?
• What typically causes punctate stains on the corneal epithelium?
• Which of the following methods is NOT used for stabilizing soft toric contact lenses?
• What type of lens adheres to the globe more effectively than other soft lens materials?
• What characteristic of a material with a lower DK value indicates its rigidity?
• Mucin balls are primarily associated with which type of lenses?
• If a soft contact lens exhibits sluggish movement, what should be done?
• Which layer of the cornea is primarily responsible for maintaining deturgescence?
• Which statement best describes the characteristics of corneal curvature?
• What common preservative found in gas permeable solutions may cause eye irritation?
• What does the BUT (break up time) test assess?
• What are the FDA Groupings of contact lenses based on water content and ionic properties?
• What is specular reflection primarily used to examine?
• What does a flat fit in an RGP lens imply?
• What is a common sign of excessive dryness in a soft contact lens wearer?
• What does lid sensation indicate when wearing contact lenses?
• How many diopters of power may be added for lenses left in the office using a soft cloth or sponge?
• If an RGP is fitted too tightly, which adjustment is recommended?
• What is a consequence of not neutralizing hydrogen peroxide solutions for at least 6 hours?
• What is the purpose of Sclerotic Scatter in clinical assessment?
• What is the normal tear break-up time (TBUT)?
• What characteristic does a profiled gas permeable lens have that differentiates it from standard lenses?
• What is the best method to correct for a low riding gas permeable minus lens?
• What is essential when using a hydrogen peroxide cleaning system?
• What is the base curve of the Back Toric lens?
• What should a fitter do to decrease overall lens diameter to make a contact lens looser?
• What characteristic of a +14 myoflange contact lens makes it suitable for a high plus prescription?
• What is likely to cause blurry near vision when wearing RGP lenses?
• What typically causes punctate stains on the corneal epithelium?
• What method can be used to loosen the fit on a rigid gas permeable (RGP) lens?
• What phenomenon can inadvertently be added to a lens if it is tilted during the surfacing process?
• What characterizes against-the-rule astigmatism?
• What should be done first if a rigid gas permeable wearer complains of poor visual acuity?
• When a soft contact lens demonstrates excessive movement, what should be considered?
• Where is the peripheral optical zone located in relation to the contact lens?
• What type of corneal astigmatism is best corrected by a back toric design lens?
• What component is essential for the cornea to remain clear and is responsible for fluid regulation?
• What is a potential effect of long-term RGP (Rigid Gas Permeable) lens wear?
• At a 36 diopter curve, what is the approximate chord measurement of the cornea that the keratometer reads?
• What does a parallelpiped illumination with a 1-2 mm slit of light primarily help to observe?
• Steepening an RGP lens can be achieved by which of the following methods?
• Which of the following indicates a tight lens fit?
• In contact lens terminology, what does the term 'hydrophilic' relate to?
• If a rigid gas permeable lens is too tight, what should be decreased?
• How can the performance of an A-8.50 gas permeable lens be improved for better lid attachment?
• Which group of individuals is more likely to experience corneal desensitivity?
• What does central pooling in RGPs indicate?
• A contact lens that is too tight is likely to cause what issue?
• Which tests use dyes to visualize damaged cells on the cornea?
• What might be a consequence of a lens that is too steep?
• What is a common cause of discoloration in contact lenses that appear pink?
• How often should a contact lens case be changed to ensure safety and hygiene?
• In the context of contact lenses, what does SL stand for when discussing illumination techniques?
• What is indicated when the corneal stroma becomes hazy?
• What is the purpose of an optic section in examining the cornea?
• The keratometer measures which portion of the cornea?
• Which type of illumination uses reflected light to observe a portion of the eye?
• What range of diopters can the BL keratometer measure?
• An example of a steep fit in contact lenses may include which of the following symptoms?
• What type of astigmatism can RGPs correct for?
• How does adding a +1.25 D lens affect the keratometer reading?
• What is the main source of oxygen for the corneal epithelium?
• If a soft contact lens shows edge lift, what adjustment should be made?
• What type of contact lenses typically require a weekly enzyme cleaning regimen?
• What does the slot gauge specifically measure?
• What is the result of a larger optical zone in a tight fitting lens?
• What is the primary purpose of polishing contact lenses in-house?
• What observation might indicate a contact lens is improperly fitted during wear?
• What four groups of pathogens must contact lens disinfection solutions be effective against according to the FDA?
• What is the condition characterized by the obstruction of the flow of aqueous humor out of the anterior chamber?
• What is the purpose of the shadowgraph in lens production?
• Which glands are responsible for secreting the lipid layer of the tear film?
• What is a disadvantage associated with soft contact lenses?
• What type of modification involves removing the bottom surface of a lens?
• What is the main function of a weekly enzyme cleaner for contact lenses?
• What is the most effective way to evaluate the movements of hydrogel lenses?
• What is the approximate curvature of the limbus in relation to the cornea?
• How do rigid gas permeable lenses work?
• A gas permeable contact lens is typically designed with a thin overall profile to achieve what effect on the cornea?
• What is the primary difference between aspheric and concentric lens designs?
• Which of the following characteristics makes chlorobutanol a preferred preservative?
• How is the base curve defined in terms of the Back Toric lens?
• Which layer of the cornea accounts for 90% of its thickness?
• A patient with keratitis sicca is more likely to develop what condition?
• What effect does excessive thickness have on contact lenses?
• When a myope switches from eyeglasses to contact lenses, what is the visual effect observed?
• Which action would tighten the fit of a contact lens?
• Which tool can verify the lens diameter, optic zone, and peripheral curve width simultaneously?
• When assessing a RGP fit, what does fluorescein indicate if there is central pooling?
• What is a side effect of taking decongestants that can affect contact wearers?
• What does lens equilibration refer to?
• Which of the following parameters indicates a higher astigmatism on the Bitoric lens?
• What does SICS stand for in regards to contact lens wear?
• If a gas permeable lens fits on the 'K' value, what is the lacrimal lens power?
• What does the visual effect of less magnification and more minification in contact lenses indicate for hyperopes?
• What can eliminate RGP lens flexure?
• When keratometer mires are only clear when the wearer blinks, what does this indicate about the lens fit?
• What indicates the amount of corneal astigmatism when using a keratometer?
• Which corneal layer facilitates transparency through its pump action?
• What ingredient is least likely to have a negative impact on the cornea?
• What is the average horizontal visible iris diameter (HVID)?
• Which system is considered most effective for removing deposits from contact lenses?
• What does a scratch-like staining pattern on the cornea indicate?
• Why should fluorescein not be used on soft contact lenses?
• What is the strength of the cornea as a refracting surface?
• In contact lens fittings, too tight an edge may cause what issue?
• Which type of contact lens design may rotate without causing visual impairment?
• What condition can prolonged use of digital devices cause due to decreased blinking?
• Which type of contact lens is specifically designed for keratoconus?
• What forms the first line of defense in the protective system of the eye?
• What type of contact lens wearing schedule should be provided?
• Which design is characterized as having both front and back toric surfaces?
• Which device is used to measure the back vertex power of a lens?
• Why does the Front Toric lens require prism ballast?
• When documenting extended keratometer readings, what should be added or subtracted based based on new readings?
• Which layer is NOT part of the cornea?
• Which factor is indicative of contact lens hypoxia during retro illumination?
• Why is it important to consider the base curve when fitting contact lenses?
• Which type of light is the best for illuminating a dynamic fluorescein pattern?
• What can cause spectacle blur in lens wearers?
• What is the effect of 3% hydrogen peroxide when it comes into contact with the eye?
• What is often recommended if a contact lens becomes stuck in the eye?
• What effect does Sorbic Acid have on contact lenses?
• What causes inferior arcuate lesion staining in the eyes?
• What action should be taken if excessive dryness is observed in a soft contact lens wearer?
• What action can increase tear exchange in RGP lenses?
• When using a radioscope, which region must the CL fitter move through before seeing the spoke pattern?
• What does the vertex distance formula indicate about power change?
• How does the cornea's curvature change as it moves away from the apex?
• What is the term for removing plastic from the bottom of a lens to create a flat edge that will control rotation?
• When is it appropriate to assess the suitability of lens design for astigmatism?
• What does an observation of vertical corneal striae in the posterior central cornea suggest?
• A patient with symptoms of poor tear exchange needs to adjust what aspect of their lens?
• Why might a silicone contact lens cause a gritty sensation for the wearer?
• What is the role of a buffering agent in contact lenses?
• Which symptom indicates a flat fit for RGP lenses?
• What condition may papillary conjunctiva indicate in a contact lens wearer?
• If a soft contact lens wearer states their vision is clear only after blinking, what does this indicate?
• Bowman's layer is known for which characteristic?
• What is the duration of the Schirmer's test for measuring tear production?
• What is the primary visual distinction in alternating visions?
• What is the purpose of a prism ballast in contact lenses?
• What is the typical set-up for measuring the steepest K in WTR astigmatism?
• What percentage of patients are non-compliant to at least one of their contact lens care regimes?
• A gas permeable lens that fits on a flatter K results in what type of lacrimal lens?
• What does stippling across the corneal surface typically indicate?
• When a gas permeable lens fits steeper than K, which statement is accurate regarding the lens power?
• What is a sign of excessive movement in a rigid gas permeable (RGP) lens?
• Which part of the cornea does the keratometer primarily measure?
• What is the first layer of the cornea?
• What condition occurs when water is forced into the layers of the eye?
• Which type of deposits are effectively managed by enzymes on contact lenses?
• What is a typical "K" reading for with-the-rule astigmatism?
• When should the follow-up for a first-time extended wear contact lens user occur?
• What is the primary action needed if a patient experiences negative symptoms after using hydrogen peroxide solution?
• Why are contact lens wearers living in dry spaces more likely to experience discomfort?
• What might cause an RGP wearer to complain of blurred vision at near?
• Which parameter is NOT associated with the Back Toric lens?
• What is measured with the Front Toric lens?
• What illumination technique utilizes a 2-4mm slit of light aimed at the limbus to observe corneal characteristics?
• What curve of the contact lens is designed to fit over the apical zone of the cornea?
• Which lens type is noted for distinct areas for both distance and reading?
• Which test is used to determine the quantity of tears produced?
• What does CLARE stand for in the context of contact lenses?
• What is the primary reason for corneal edema under a prism ballast?
• Which symptoms indicate a tight fitting lens?
• Vertically oriented, delicate lines located near the level of the stroma are called what?
• What is the primary purpose of a surfactant cleaner?
• How long can extended wear contact lenses typically be worn continuously?
• What adjustment should be made if an RGP lens is too flat?
• What is the primary function of soaking solutions for contact lenses?
• What is a common characteristic of soft toric contact lenses?
• A lot of apical vaulting in an RGP lens indicates what kind of fit?
• In K-readings, what does the smallest number represent?
• Which preservative is noted for being the least likely to cause discoloration in contact lenses?
• Which type of illumination is primarily used for examining the globe and extraocular structures?
• What is a common issue if the curve of the reflected light on a lens surface is not smooth and flowing?
• How much prism is required for proper orientation in a prism ballasted gas permeable lens?
• What effect does a steep fit have on the power of the lacrimal lens?
• What does a high magnification during an optic section allow an examiner to see?
• What is the normal vascular state of the cornea?
• What are soft lenses most likely to be coated with?
• How does a silicone lens typically behave when in contact with water?
• Which instrument is used specifically to measure the posterior optical zone diameter?
• What is one benefit of using a thicker lens for managing mild corneal astigmatism?
• How often should extended wear contact lens users remove their lenses for disinfection?
• If you want to increase tear exchange in a lens fitting, what must be done?
• What are the two primary functions of a radioscope?
• Which in-office modification is considered the easiest to perform on a lens?
• When fitting a gas permeable lens steeper than the K reading, what type of power does the lacrimal lens have?
• What is the primary function of oxygen in the context of contact lens wear?
• How does prism ballast work in contact lenses?
• What is indicated by excessive lag in an RGP lens fitting?
• Which area of the cornea contains the highest curvature?
• When inspecting for a warped lens, what tool is used to identify the base curves?
• During the manufacture of a contact lens using a lathe, what should be avoided to prevent distortion?
• What can cause an RGP lens to displace?
• What is a possible outcome of using high concentrations of sorbic acid in soft contact lenses?
• What type of astigmatism is the Front Toric lens specifically used to address?
• What could excessive movement of a soft contact lens suggest?
• For how long should contacts be soaked if no specific time is provided by the manufacturer?
• What does superior punctate staining indicate?
• What is required for a preservative to be effective in contact lens solutions?
• What condition indicates that a Bitoric lens might be necessary?
• Which staining on the cornea suggests toxicity from contact lens solutions?
• Which of the following is true about with-the-rule astigmatism?
• Which corneal layer is known for being extremely thin and innermost?
• Lenticular or residual astigmatism can be corrected by which type of contact lens?
• What tool is used to measure the diameter of a rigid lens?
• What should a clinician look for in the first follow-up exam after fitting extended wear lenses?
• What is the appropriate action to take when there is insufficient tear exchange with a contact lens?
• How is the relationship between lens diameter and base curve expressed in terms of change?
• What is the typical diopter difference of the secondary curve of a RGP compared to the Central Power Curve (CPC)?
• What type of agent should patients use to clean their contact lenses upon removal?
• What is a key drawback of silicone lenses related to their surface characteristics?
• A patient with aniridia and photophobia is likely to require which type of lenses?
• What does the expiration date of a contact lens indicate?
• What can decreased blinking during prolonged digital device use lead to?
• What does it mean if an RGP lens has no apical clearance?
• What is a common abnormal response reported by contact lens wearers?
• What characteristic of silicone lenses contributes to the formation of mucin balls?
• What is a common Rx example for against-the-rule astigmatism?
• What needs to be determined using the Edge Flare method?
• What does the staining pattern known as Acruate indicate?
• What can result from using hydrogen peroxide as a rinsing agent?
• What is the primary use of a shadowgraph in contact lens evaluation?
• What is the primary purpose of an enzyme in the context of contact lens care?
• What happens to the tear pH when the buffering agent alters an ingredient?
• What is the typical measurement format for describing a toric lens?
• What is a notable disadvantage of hydrophilic contact lenses?
• What happens when a lens fits flatter than K in terms of its lacrimal lens?
• Which type of staining is an indication of excessive dryness in contact lens wearers?
• When are soft lenses considered to be poorly fitted?
• In which meridian will a spherical RGP lens touch if fitted to a patient with high oblique astigmatism?
• How might an emerging presbyope who is hyperopic benefit from contact lenses?
• What term is used to describe the smooth junctures between curves on the posterior surface of a lens?
• In a Back Toric lens, what should the corneal astigmatism be compared to the refractive astigmatism?
• What is the recommended method for cleaning residue from gas permeable lenses?
• Which contact lens parameter is associated with lens bends and the "ski effect"?
• What is typically a sign of a poorly finished transitional zone in contact lenses?
• Why might a lens ride high on a person's eye?
• What symptom is most likely caused by a damaged contact lens?
• What color change does Thimerosal cause in contact lenses?