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2026 Edition

Contact Lens Practice Test

Take this free Contact Lens Practice Test to study for the Contact Lens Registry Exam (CLRE).

The CLRE is taken by opticians to become certified in contact lens dispensing. The CLRE has a 125 multiple choice questions and two hours is given to complete the exam. It covers the following eight domains: (1)  Ocular Anatomy, Physiology and Pathology; (2) Refractive Errors; (3) Instrumentation for Measurement and Observation; (4) Prefitting; (5) Diagnostic Fitting; (6) Dispensing; (7) Follow-up; and (8) Regulatory and Administrative.  

For comprehensive study, try our 350 question CLRE Practice Test. It is written by optician instructors. Our interactive test platform allows you to simulate the exam. Take as many practice tests as you need. There's no time limit or recurrent charges.

For more information on the CLRE and test prep, see our CLRE Study Guide.

For more free practice questions and test prep, try our NOCE Optician Practice Test. 
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Ocular Anatomy, Physiology, and Pathology 

1 Which anatomical part of the eye can have up to 33 diopters of optical power?
Incorrect. Please choose another answer.
As the eye is accommodating, the crystalline lens makes up to 33 diopters (D) of its optical power. In a relaxed state, the lens usually has 20 D of power while the other majority of the eye's 60 D of total optical power is from the cornea. The iris and vitreous humour do not refract light.

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2 A common finding in macular degeneration is:
Incorrect. Please choose another answer.
Macular degeneration impacts the retinal and subretinal structures of the eye. Drusen are yellowish deposits that form under the retina. The other answers do not directly involve the retina.
3 What is the name of a common noncancerous growth on the conjunctiva?
Incorrect. Please choose another answer.
A pinguecula is a common noncancerous growth that forms on either or both sides in the conjunctival tissue. These pingueculae are often yellowish in color. Cataract and macula refer to different parts of the eye. An eyelid papilloma (another type of growth) would not be confused with a pinguecula due to being located on a different structure of the eye.
4 Which eye structure can change shape (accommodate) allowing an image to be focused on the back of the eye?
Incorrect. Please choose another answer.
The lens inside the eye can alter its shape (known as accommodation) to facilitate a focused image on the back of the eye (retina). The retina and vitreous do not change shape in order to see clearly. The trabecular meshwork does not play a direct role in seeing an image clearly.

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5 Irregular astigmatism (keratoconus) is caused by which part of the eye?
Incorrect. Please choose another answer.
If the cornea develops an irregular shape, it produces the refractive error known as irregular astigmatism. Normally, the cornea has a regular shape which may result in regular astigmatism. More advanced irregular astigmatism often necessitates custom contact lenses or surgery in order to significantly improve vision. The other eye structures mentioned do not produce irregular astigmatism.
6 On which part of the eye do styes (chalazia) usually develop?
Incorrect. Please choose another answer.
A chalazion develops when a meibomian gland (oil gland) gets blocked. The oil gets backed up within the gland causing swelling in the eyelid. The oil can harden and develop into a bump.
7 ______ is inflammation of the upper tarsal conjunctiva resulting in large papillae and is associated with contact lens wear.
Incorrect. Please choose another answer.
Giant papillary conjunctivitis is commonly associated with poor cleaning of contact lenses. This causes irritation of the palpebrae conjunctiva of the upper lid. The resulting inflammation leads to very large papillae (or bumps). Pterygium is a growth in the conjunctiva and a subconjunctival hemorrhage is when a blood vessel in the conjunctiva breaks. Atopic keratoconjunctivitis is characterized by chronic inflammation of the conjunctiva.

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Refractive Errors 

8 A ________ eye focuses light ____ the retina.
Incorrect. Please choose another answer.
In myopia (nearsightedness) light focuses in front of the retina, whereas with hyperopia (farsightedness) light focuses behind the retina. An emmetropic eye requires no correction because light already focuses on the retina.
9 Which term describes the property of a lens that is thickest in the middle?
Incorrect. Please choose another answer.
A convex (plus) lens is used to correct hyperopia. A concave (minus) lens is used to correct myopia. A cylindrical lens corrects astigmatism.

Instrumentation for Measurement and Observation 

10 All of the following can be used in establishing a patient's contact lens prescription except:
Incorrect. Please choose another answer.
A pupilometer is used for fitting a patient for glasses. A phoropter is a machine which assists the prescriber in refracting the eye while a keratometer measures the patient's cornea. Corneal topography can also be used when a patient requires rigid gas permeable or hybrid lens.

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11 Two sets of lines, typically green in color, that must be focused and orientated correctly to determine the cylinder power of a lens is known as (a):
Incorrect. Please choose another answer.
Mires refers to the image of two sets of lines (typically green in color) that must be orientated correctly and focused to reveal the cylinder power of a lens. Lensometer is an instrument (not the image) used to determine the power of a lens. PD rulers and lens clocks are optical instruments that are used for other purposes.
12 A device commonly used to screen for keratoconus is a(n):
Incorrect. Please choose another answer.
The corneal topographer takes measurements of the corneal shape including its curvature. Characteristic asymmetry of corneal curvature is a significant feature of keratoconus. Corneal topography is commonly utilized to detect corneal curvature deviations suggestive for keratoconus. The other devices mentioned do not measure corneal curvature.
13 A device that holds many lenses and assists in determining refractive error is referred to as a:
Incorrect. Please choose another answer.
A phoropter holds many lenses and is used to derive a patient's refractive error. The other possible answers are devices that do not hold many lenses and/or do not assist in determining refractive error.

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14 An instrument that is commonly used to determine the refractive error of an eye is called a(n):
Incorrect. Please choose another answer.
Retinoscopy is the process of using a retinoscope device to determine the refractive error of an eye. The other devices mentioned are not commonly used to determine the refractive error of an eye. A direct ophthalmoscope can potentially be used to get an estimate of refractive error, but this instrument is not commonly used for this purpose. A direct ophthalmoscope is typically used to view the back of the eye (retina).
15 Which test can be used to measure if a patient's dry eye symptoms are too severe for contact lens wear?
Incorrect. Please choose another answer.
Tear Break-Up Time (BUT) is a test where fluorescein dye is used to track how long it takes dry spots to form after a patient blinks. Visual acuity (or the patient's ability to see) and refraction (the process of determining a patient's refractive error) are normal parts of an eye exam. Knowing which eye is dominant is essential for fitting monovision and some multifocal lenses.
16 If a patient has a glasses prescription of -3.00 -2.00 x 130 and corneal measurements of 45.00/43.00 x 130, which type of astigmatism is present?
Incorrect. Please choose another answer.
Since there is a 2 diopter (D) difference between the corneal measurements of the eye and also the amount of cylindrical power listed in the refraction, the patient has corneal astigmatism. The patient's astigmatism is not caused by the difference in curvature of the crystalline lens (lenticular astigmatism). The astigmatism at 130 degrees is also known as oblique astigmatism. Against-the-rule astigmatism is described as an axis located approximately between 0 degrees to 30 degrees or 150 degrees to 180 degrees. With-the-rule astigmatism is described as an axis located approximately between 60 degrees to 120 degrees.

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Prefitting 

17 After transposing the following glasses prescription, what is the next step in determining this contact lens prescription?
OD +3.50 +2.50 x 075
Incorrect. Please choose another answer.
A spectacle prescription is transposed by adding the cylinder power to the sphere, switching the cylinder's sign and changing the axis by 90 degrees. The transposed prescription will read +6.00 -2.50 x 165. Since the sphere is higher than +4.00, the next step is to adjust for the vertex effect. The corresponding contact lens prescription will then be +6.50 -2.50 x 165.
18 What are scleral contact lenses commonly used for?
Incorrect. Please choose another answer.
Soft contact lenses often do not provide the best visual acuity for moderate or advanced irregular corneas. Standard rigid contact lenses may not fit over an irregular cornea well. Scleral lenses vault over the irregular corneas to increase the chances of providing better visual acuity and fit.
19 During fitting of contact lenses, corneal curvature measurements are used to determine which contact lens parameter?
Incorrect. Please choose another answer.
Corneal curvature measurements are not used to determine diameter or type of contact lens tint. HVID refers to horizontal visible iris diameter. HVID is sometimes helpful for certain types of contact lens fittings.

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20 To convert a plus cylinder form spectacle prescription to a contact lens prescription, the axis needs to be changed by:
Incorrect. Please choose another answer.
Contact lens prescriptions are typically recorded in minus cylinder form. For example, a spectacle Rx in plus cylinder form of -0.25 + 0.75 x 90 would be converted into minus cylinder form of +0.50 - 0.75 x 180.
21 Which of the following base curves will fit the eye best if the patient has a corneal measurement of 41.00/41.25 x 90?
Incorrect. Please choose another answer.
The corneal measurement (K) of 41.00/41.25 x 90 is considerably steep and matches up best with the 8.2 base curve (BC). Usually the higher the BC, the flatter the contact lens will appear.
22 Which eye condition would benefit the most from a hybrid contact lens?
Incorrect. Please choose another answer.
Keratoconus is a thinning of the cornea which leads to a steep coning of the front of the eye. Hybrid lenses (Rigid Gas Permeable lenses with a soft lens skirt) therapy can be used to improve vision. When either the front surface of the eye, the cornea, or the lens inside the eye have mismatched or misshapen curves, astigmatism occurs causing blurred vision at all distances. Presbyopic patients require additional plus power in certain zones of the contact lens in order to help accommodate for lost near vision. A cataract is a clouding of the crystalline lens.

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23 A contact lens that contains an additional plus power in certain zones to assist presbyopic patients is also called a:
Incorrect. Please choose another answer.
Presbyopic patients require additional plus power in certain zones of the contact lens in order to help accommodate for lost near vision. Another option is monovision where one eye is corrected for far vision and the other eye is corrected for near vision. A toric (or cylindrical) lens corrects astigmatism.

Diagnostic Fitting 

24 What factors should be considered when selecting a lens for a patient?
Incorrect. Please choose another answer.
The patient's daily activities and age range are important factors to consider for a successful contact lens fitting (including what modality of lenses should be chosen). Unless a contact lens is custom made, a fitter will have to select a brand with parameters that match the patient's contact lens prescription.
25 Which one of the following statements is true about insertion and removal of soft contact lenses?
Incorrect. Please choose another answer.
Soft lenses can be inserted by placing them anywhere on the sclera. Unlike soft lenses, Rigid Gas Permeable (RGP) lenses must be placed on the cornea for proper insertion. RGP lenses can also be removed by blinking while your hand is placed in the outer corner of the eye or with use of a contact lens plunger.

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26 Which of the following is not a characteristic of an optimal RGP lens fit?
Incorrect. Please choose another answer.
A flat fit is not an ideal RGP fit. A fluorescein pattern resembling a bullseye with apical clearance is optimal. The fitter also will check that the lens is not too tight allowing for slight dynamic movement.
27 While fitting a patient with a toric soft lens in the prescription below, it is observed the lens is over-rotated by 10 degrees to the left. How should the prescription be adjusted?
Incorrect. Please choose another answer.
The over-rotation of the toric lens is causing the effective contact lens prescription to be 1.75 -1.25 x 080. In order to get the desired effective contact lens prescription, 10 degrees must be added to the original prescription. If the over-rotation had been to the right, 10 degrees would need to be subtracted instead.
28 A patient returns for a toric contact lens fitting follow-up and complains of temporary blurriness after blinking. The patient states this is a concern since their job performance relies heavily on their vision. How can this be resolved?
Incorrect. Please choose another answer.
Temporary blurriness after blinking is caused by excessive contact lens movement. The patient should be refitted in toric lenses with either a different ballast system or decreased base curve to decrease unwanted movement. If the blurriness was resolved by blinking, this is an indication of dry eyes, dictating the use of rewetting drops. Masking of the astigmatism with spherical lenses will provide less movement but will not improve visual acuity.

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Dispensing 

29 If a contact lens is monthly wear, which one of the following statements is true?
Incorrect. Please choose another answer.
A monthly contact lens should only be used for a 30-day period, regardless of how many days the contact lens is worn during the 30 days. Patients should not sleep in contact lenses.
30 Which type of soft contact lens does not require daily disinfecting, as long as contact lenses are removed from eyes each day?
Incorrect. Please choose another answer.
Daily disposable contact lenses do not have to be disinfected at the end of the wearing day since these lenses are disposed of after each wear. Soft contact lenses that are reused should be disinfected after each use.
31 Which type of eye related solution is not safe to go directly in the eyes?
Incorrect. Please choose another answer.
Hydrogen peroxide solution can damage the eyes and should not be put in the eyes. Multipurpose contact lens disinfection solution is generally safe for the eyes although it is not a recommended eye rinse solution. Rewetting eyedrops and saline eye rinse solution can be safely put in the eyes.

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32 All of the following instructions should be given to new weekly and monthly disposable contact lens wearers, except:
Incorrect. Please choose another answer.
Patients are allowed to purchase their contact lenses anywhere they choose. Patients cannot be forced to purchase their contact lenses where the fitting was done. The prescriber requiring that the patient must purchase contact lenses from the prescriber may face legal consequences.
33 Which of the following would be least harmful to the eyes?
Incorrect. Please choose another answer.
Replacing contact lenses on a frequent basis can reduce the risk of eye infection and/or inflammation. The remaining potential answers may increase the risk of eye infection.
34 When dispensing a contact lens, what steps are recommended to verify the contact lens is correct for the patient?
Incorrect. Please choose another answer.
All of the steps listed are recommended to verify that a contact lens is correct for the patient.

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35 All of the following needs to be included in the contact lens prescription, according to the Contact Lens Rule, except:
Incorrect. Please choose another answer.
Any information concerning the health of the patient's eyes does not need to be added to the contact lens prescription. The other information is required to in the contact lens prescription according to the Contact Lens Rule.
36 For a new fit, which type of contact lens requires the longest period for building up wear time?
Incorrect. Please choose another answer.
In fitting RGPs, also known as hard lenses, it is recommended that the patient builds up wear time by adding an hour each day. Soft lenses are made from silicone hydrogel or hydrogel material.
37 Which type of contact lens solution requires a process of 6 to 8 hours for the lenses to be safe for wear?
Incorrect. Please choose another answer.
All of these solutions can be used with contact lenses however, since the hydrogen peroxide solution contains hydrogen peroxide to disinfect the lenses, the patient must use the provided case which includes a neutralizing disc. The active ingredient will be completely neutralized by the time listed in the instructions, usually 6 to 8 hours (or overnight). This type of solution may be recommended for patients with allergies to preservatives found in other types of contact lens solution.

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38 Which one of the following statements is true?
Incorrect. Please choose another answer.
Saline solution does not disinfect contact lenses. It is only a combination of sodium chloride and sterilized water. Multipurpose contact lens solution is a disinfectant used to clean lenses and usually contains preservatives.
39 Which of the following does not increase a patient's risk of eye infection?
Incorrect. Please choose another answer.
Topping off old contact lens solution and swimming in contact lenses increases a patient's risk of eye infection. In fact, any normal use of contact lenses can increase risk of infection. This is why it is important to wash hands before/after handling, not sleep in the lenses and clean them properly.
40 This should not be used to clean soft contact lenses:
Incorrect. Please choose another answer.
Using any type of water to clean contact lenses will increase the risk of eye infection. One corneal infection associated with distilled or tap water is Acanthamoeba Keratitis.

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Follow-up 

41 Which of the following would be considered a subjective follow-up finding?
Incorrect. Please choose another answer.
The comfort level of the contact lens is a subjective finding given by the patient. Over-refraction, visual acuity and over-rotation are measured objective findings.
42 Which of the following would be considered an objective follow-up finding?
Incorrect. Please choose another answer.
The measured visual acuity of the contact lens is an objective finding. Subjective findings include the patient's feelings and opinions about the contact lenses.
43 What is typically not included in the contact lens follow-up?
Incorrect. Please choose another answer.
Visual acuity test, over-refractions and refitting are common parts of a contact lens follow-up to fine-tune the prescription, while refraction usually occurs at the initial exam. For this reason sometimes the prescriber will not provide a finalized contact lens prescription until the patient returns for the follow-up.

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44 If the eye becomes red during contact lens wear, the patient should be advised to do the following except:
Incorrect. Please choose another answer.
The patient should not leave the contact lens on the eye and flush with tap water. There is a chance that the contact lens is contributing to the redness. Tap water is not sterile and putting it directly on the eye, especially with a contact lens on the eye, can increase the risk of infection. The other answers are appropriate.
45 A contact lens follow up visit should include which of the following verifications?
Incorrect. Please choose another answer.
A contact lens follow up should ensure the contact lens is fitting the eyes appropriately, verify that consistent good visual acuity is obtained and verify that the patient is comfortable before purchasing a supply.
46 During a contact lens follow up, the patient's vision is blurry with a soft toric contact lens. Which of the following would not be helpful in determining the cause of the blurry vision?
Incorrect. Please choose another answer.
Checking the type of disinfection solution may help in determining eye health issues, not vision issues. Verifying the type of disinfection solution would unlikely be helpful in discovering why the vision is blurry with a soft toric contact lens. There are many options for astigmatic patients, which may be the case here. The soft toric lens can be modified by performing an over-refraction and using the hash mark on the contact lens to make adjustments. If a soft toric contact lens cannot provide satisfactory vision, even after all changes are attempted or made, there are other options for the patient, including rigid and scleral contact lenses.

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47 Patients should be instructed to remove contact lenses from their eyes and call an eye doctor when:
Incorrect. Please choose another answer.
Patients should remove contact lenses from their eyes and call an eye doctor when the eye becomes red. Redness is often a sign of inflammation and/or infection. A patient does not have to remove the contact lenses and call an eye doctor for the other reasons listed.
48 The following are all part of proper follow up care for soft contact lenses except:
Incorrect. Please choose another answer.
Soft contact lenses cannot be stored dry. Contact lenses must be kept hydrated to maintain their integrity. It is never acceptable to store soft contact lenses in water. Water contains microorganisms that increase the risk of infection for soft contact lens wearers. Patients wearing soft contact lenses must use a disinfection solution specifically made for soft contact lenses.
49 Signs that a contact lens is fitting too tightly on a follow up visit include which of the following?
Incorrect. Please choose another answer.
The answers listed are characteristic features of a tight-fitting contact lens.

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50 A patient comes in for contact lens follow up visit with a red, painful eye with a white spot on the cornea. A possible diagnosis would be:
Incorrect. Please choose another answer.
A possible complication of contact lens wear is corneal ulceration. This risk increases with extended wear use of soft contact lenses. The other diagnoses listed are not directly found in the cornea.
51 After the contact lens prescription is finalized, when should the patient contact the prescriber?
Incorrect. Please choose another answer.
A patient should contact the prescriber in any of the above situations. Sudden changes in vision or trouble handling the lenses should be addressed as soon as possible. Once a contact lens prescription expires, a patient will be unable to receive any lenses until they have a new exam.

Regulatory and Administrative 

52 Under FDA regulations:
Incorrect. Please choose another answer.
The Food and Drug Administration regulates contact lenses because they are a medical device. Contact lenses require a valid prescription which includes the contact lens brand for purchase.

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53 All of the following are exemptions to a prescriber being legally obligated to provide a copy of a patient's contact lenses prescription at the end of evaluation except:
Incorrect. Please choose another answer.
As long as a patient has paid their eye exam/contact lens fitting fees and the prescriber has finalized their contact lens prescription, a copy of this prescription must be given to the patient as mandated by the Fairness to Contact Lens Consumers Act.
54 Under HIPAA, which of the following scenarios is prohibited:
Incorrect. Please choose another answer.
According to the Health Insurance Portability and Accountability Act of 1996 (HIPAA), for patients 18 years and older, patient consent is needed to share medical information. However, this medical information must be shared through secure methods. Sending the contact lens prescription through the person's patient portal which is encrypted, is a more secure option then using non-encrypted e-mail.

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55 The Fairness to Contact Lens Consumers Act states that it is ________ for a patient to purchase contact lenses from a seller other than the prescriber if the contact lens prescription is ____________.
Incorrect. Please choose another answer.
According to the Federal Trade Commission's Fairness to Contact Lens Consumers Act, a contact lens prescription must be verified and unexpired in order for the patient to legally purchase contact lenses from a seller other than the prescriber.

Related Links

Quality starts with who wrote the material. Our writers:

Justin Mathias, ABO, NCLEC, is a licensed dispensing optician and education content creator with over 20 years of experience in the optical field. He is a former editor at the Optical Training Institute.

Crystal Deckert, Former ABO, NCLEC, was a licensed optician for over 10 years. She worked as a general manager and lead optometrist for National Vision where she was responsible for staff training.

Our practice exam follows the Contact Lens Registry Exam (CLRE) content outline:

Occular Anatomy
Occular Physiology
Occular Pathology
Refractive Errors
Instrumentation
Prefitting
Diagnostic Fitting
Dispensing
Follow-up
Regulatory
 
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