Contact Lenses MCQ Quiz With Answers

When checking the physical fit of a lens, three components are evaluated: movement, centration, and coverage. Movement refers to the ability of the lens to move slightly on the eye with each blink, ensuring comfort and proper tear exchange. Centration refers to the position of the lens on the cornea, ensuring optimal visual acuity and minimizing potential complications. Coverage refers to the extent to which the lens covers the cornea, ensuring proper alignment and stability. These three components are crucial in determining the suitability and effectiveness of a lens for a specific individual.

The major source of oxygen for the endothelium is the aqueous humor. The aqueous humor is a clear fluid that fills the front portion of the eye, between the cornea and the lens. It provides nutrients and oxygen to the cornea and the endothelium, which is the innermost layer of the cornea. This oxygen supply is crucial for maintaining the health and function of the endothelium, which plays a vital role in maintaining the transparency and clarity of the cornea.

A loose fitting lens refers to a lens that does not fit tightly on the eye. When a lens is loose, it tends to move more easily and can cause a large lateral lag. Lateral lag refers to the sideways movement of the lens when the eye moves. Therefore, a lens with a loose fitting is expected to have a large lateral lag.

The statement "all of the above are true" indicates that all the statements provided about the curvature map are correct. This means that the sagittal map assumes the center of the radius of that curvature is always on a central axis, the tangential curvature does not assume where the center of the radius is, and the mean curvature eliminates corneal astigmatism in order to highlight underlying features.

Emptying the case, rinsing with disinfecting solution, and letting it air dry is a correct technique regarding hygiene and contact lenses. This process helps to remove any debris or bacteria from the case, ensuring that the lenses are stored in a clean and safe environment. Replacing a contact lens case every 4-6 months is also a good practice to prevent the buildup of bacteria. Using hand sanitizer before insertion can help to minimize the risk of introducing bacteria to the eyes. However, digitally scrubbing the case with tap water is not recommended as it may introduce contaminants and potentially damage the case.

Poor tear film is the number one reason for a patient to discontinue contact lens wear. This is because a healthy tear film is essential for maintaining the comfort and clarity of contact lenses. If the tear film is inadequate, it can lead to dryness, discomfort, and irritation, making it difficult for the patient to continue wearing contact lenses. Without proper tear film, the lenses may not fit properly on the eyes, causing further discomfort and potential damage to the cornea. Therefore, addressing and improving tear film quality is crucial for successful and comfortable contact lens wear.

Prism balast is the contact lens stabilization technique that would have a thicker inferior portion of the lens with reduced O2 transmissibility in the thick zone and use gravity and lid force to put the lens in position.

Pachymetry is a measurement of corneal thickness and is used to assess corneal edema. This means that pachymetry is used to determine the thickness of the cornea, which can be an indicator of corneal edema, a condition characterized by swelling of the cornea. By measuring corneal thickness, pachymetry can help in diagnosing and monitoring corneal edema.

The given question asks for a characteristic that is not associated with poor contact lens candidates. The correct answer is "high refractive errors." This means that individuals with high refractive errors can still be suitable candidates for contact lenses. The other options, such as dry eyes, tobacco smokers, and medications, are commonly considered as factors that may make someone a poor candidate for contact lenses.

The correct answer is autoimmune disease, antihistamine use, and irregular astigmatism. Autoimmune diseases can cause inflammation and dryness in the eyes, making them unsuitable for wearing soft contact lenses. Antihistamines can also cause dryness in the eyes, which can lead to discomfort when wearing contact lenses. Irregular astigmatism refers to an irregularly shaped cornea, which can cause vision distortion and make it difficult for soft contact lenses to fit properly. Occasional wear is not a contraindication for soft contact lenses, as long as proper care and hygiene are maintained.

b,c, and d are due to user error or environment

optifree has polyquad in it

The stimulus to accommodate in hyperopes does not increase as a lens is moved toward the eye. This statement is incorrect because hyperopes have difficulty focusing on near objects due to their shorter eyeball length, so the stimulus to accommodate actually decreases as a lens is moved closer to the eye. Hyperopes require converging lenses (BO) to help them focus on near objects.

Longstanding contact lens wearers may experience various changes in their tear film due to the prolonged use of lenses. These changes can include a decreased tear meniscus, decreased tear break-up time (TBUT), and decreased levels of phospholipids. However, increased tear pH is not typically observed in longstanding contact lens wearers.

daily disposables are ideal for allergies, heavy depositors, and occasional wearers

Corneal neovascularization is the growth of new blood vessels in the cornea, which is a response to chronic lack of oxygen. In acute lack of oxygen, the cornea does not have enough time to develop new blood vessels, so corneal neovascularization is not a physiological change associated with it. The other options, stromal edema, epithelial microcysts, and endothelial folds, are all physiological changes that can occur in response to acute lack of oxygen to the cornea.

The question asks for the option that is not a possible treatment for dryness experienced with soft lenses. Vitamin D supplements are not a treatment for dryness in the context of soft lenses. Vitamin D supplements are typically taken to address deficiencies in the body and promote overall health, but they do not directly treat dryness in the eyes caused by soft lenses. Therefore, vitamin D supplements are the correct answer.

Myopes, who have nearsightedness, need to accommodate and converge more with contact lenses (CLs) compared to wearing spectacles. This is because contact lenses sit directly on the eye, causing the myopic eye to exert more effort to focus on near objects. On the other hand, hyperopes, who have farsightedness, need to accommodate and converge less with contact lenses compared to wearing spectacles. This is because contact lenses correct the hyperopic eye's focusing power, reducing the need for accommodation and convergence. Therefore, the statement that myopes must accommodate and converge more with CLs than specs and hyperopes must accommodate and converge less with CLs than specs is correct.

Based on the given information, the correct answer is to monitor the patient to prevent further neovascularization. Neovascularization refers to the growth of new blood vessels, which can be a sign of an underlying condition or a complication related to contact lens wear. By monitoring the patient regularly, the healthcare professional can assess the progression of the neovascularization and take appropriate actions if necessary, such as adjusting the contact lens fit, changing the material, or advising the patient to discontinue contact lens wear. Simply doing nothing may lead to worsening of the condition, so monitoring is essential.

The correct answer is "two of the above will work" because both Revitalens and Opti-Free Puremoist are effective against bacteria that may be present in freshwater. By changing their current chemical disinfection solution to either of these options, the patient can continue to wear their contact lenses while reducing the risk of infection.

Acne rosacea is a chronic skin condition that primarily affects the face, causing redness, pimples, and visible blood vessels. It is not a tear film surface abnormality because it does not directly affect the tear film or its production. Tear film surface abnormalities typically involve issues with the composition or stability of the tear film, such as dry eye syndrome or meibomian gland dysfunction. Therefore, acne rosacea is the correct answer as it does not fit the criteria of a tear film surface abnormality.

A tight lens is typically associated with clear vision immediately after a blink, little to no movement or lag, and the ability to buckle or wrinkle centrally. However, blur vision occurring after a full blink is not a characteristic of a tight lens.

H in hema: hydro so high water content

(4weeks/mo)(12 mo/yr)= 48 wks/yr (1 cl/2wk)(48 wk)= 24 cl (24 cl)(1 box/6cl)= 4 boxes/eye 8 boxes total

Myopes, or nearsighted individuals, often report things looking larger with contact lenses (CLs) because the lenses correct their blurry vision, making objects appear clearer and closer. Additionally, myopes will have less minification with CLs, meaning that objects will not appear smaller as they would without corrective lenses.

The patient is experiencing stinging and injection upon insertion of their contact lenses, indicating that their current contact lens solution may be causing irritation. The best option of care would be to recommend using Opti-Free PureMoist by Alcon to replace the current contact solution. This solution is known for its moisturizing properties and is designed to provide comfort and hydration for contact lens wearers. By switching to Opti-Free PureMoist, the patient may experience less stinging and irritation during lens insertion.

A patient with less oxygen consumption in the cornea due to contact lens abuse may exhibit microcysts and endothelial folding. Microcysts are small fluid-filled spaces that form within the cornea as a result of chronic hypoxia, which occurs when the cornea does not receive enough oxygen. Endothelial folding refers to the folding or pleating of the endothelial layer of the cornea, which can also be caused by prolonged hypoxia. These symptoms are indicative of corneal damage and can be seen in patients who abuse contact lenses by wearing them for extended periods without proper oxygenation.

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Soft contact lenses provide several advantages, such as little movement, wettability, and being simple to fit. However, the quality of vision is not one of these advantages. While soft contact lenses can correct vision, they may not provide the same level of visual acuity as glasses or rigid gas permeable lenses. This is because soft lenses are more prone to distortions and may not provide as crisp and clear vision as other options. Therefore, the quality of vision is not an advantage of soft contact lenses.

If you have a loose lens, changing to a smaller diameter would not be the correct solution. A smaller diameter would only make the lens fit even looser, potentially causing discomfort and poor vision. Instead, you should consider changing to a larger diameter to ensure a better fit and stability for the lens.

The corneal curvature is not flattest at its apex. The cornea is actually steepest at its apex, which is the center of the cornea. As the cornea transitions into the sclera, it gradually flattens. The corneal curvature and scleral curvature are usually not the same, as the sclera has a different shape and curvature compared to the cornea. Additionally, the cornea does not have a perfect spherical curvature at any location, as it has a slightly asymmetrical shape.

A superior shift on the topographer is not indicative of keratoconus. Keratoconus is a condition characterized by a cone-shaped bulge in the cornea, which causes vision problems. A superior shift on the topographer refers to a displacement of the corneal shape towards the superior (upper) part of the eye. This shift can be caused by various factors, such as eyelid pressure or contact lens wear, and is not specific to keratoconus. Therefore, a superior shift on the topographer is not a reliable indicator of keratoconus.

A hyperopic patient wearing contact lenses is most likely to see better at near without an add power because contact lenses move with the eye, allowing for a wider field of vision and a more natural focusing ability. This helps to correct the hyperopia and allows for better near vision without the need for additional reading glasses.

Keratoconjunctivitis sicca, also known as dry eye syndrome, is a systemic condition associated with dry eyes. Rheumatoid arthritis, an autoimmune disease, can also cause dry eyes as a result of inflammation. Thyroid conditions, such as hypothyroidism or Graves' disease, can lead to dry eye symptoms due to hormonal imbalances. High blood pressure, however, is not directly associated with dry eyes.

inner layer is glycocalyx produced by epithelial cells
outer is goblet cells, manz glands and crypts of henle
insufficent tear meniscus: aq deficiency

you're not likely to cure the problem

This statement is incorrect because oxidative disinfectants do not contain preservatives. Unlike chemical disinfectants, oxidative disinfectants do not require the use of preservatives to maintain their stability and effectiveness. Therefore, someone who is sensitive to the preservatives in chemical disinfectants does not need to be cautious of the preservatives in oxidative disinfectants.

saline= cheap acanthamoeba= more likely when swim in lenses

Excessive movement when wearing soft contact lenses can be caused by deposited lenses. Deposits can accumulate on the surface of the lenses over time, causing them to become less smooth and slippery. This can lead to increased friction between the lenses and the eye, resulting in excessive movement. Regular cleaning and proper maintenance of the lenses can help prevent deposits from building up and minimize this issue.

The Schirmer test and the phenol red thread test are both used to evaluate the quantity of the tear film. The Schirmer test measures the amount of tears produced by placing a small strip of filter paper inside the lower eyelid, while the phenol red thread test measures tear production by using a thread that changes color when it comes into contact with tears. Both tests are commonly used in ophthalmology to assess tear production and diagnose conditions such as dry eye syndrome.

While it's important to regularly clean and disinfect contact lens cases, it's not necessary to disinfect and air dry the case each time the lenses are inserted. Instead, the case should be cleaned and disinfected regularly as per the manufacturer's instructions, typically at least once a day, and replaced every few months.

PC=Aq>LV
the aq and palpebral conj each suuply roughly the same amount of oxygen

The advantages of soft contact lenses include initial comfort and being hard to dislodge. Soft lenses are known for their comfort, as they are made from flexible materials that conform to the shape of the eye. Additionally, they have a lower risk of dislodging compared to rigid lenses, making them more convenient and secure for wearers.

Cosmetics, such as eye makeup and solutions, should be replaced regularly to prevent bacterial growth and reduce the risk of eye infections. Waiting for 5 months before replacing cosmetics increases the risk of contamination and infection. Therefore, it is not a hygienic practice for contact lens wearers.

Possible contraindications for contact lens wear include corneal infiltrates and Fuchs endothelial dystrophy. Corneal infiltrates refer to the presence of white blood cells in the cornea, which can be a sign of infection or inflammation. Fuchs endothelial dystrophy is a progressive disease that affects the cells lining the inner layer of the cornea, leading to vision problems. Both of these conditions can potentially worsen with contact lens wear, making it important to avoid wearing contact lenses in these cases.

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LARS (RS)

Wearing hydrogel lenses, not sihys, overnight can lead to a common complication known as myopic shift. This refers to a temporary change in vision where the person becomes more nearsighted. This can occur due to the cornea molding to the shape of the lens, resulting in a change in the way light is focused on the retina. However, it is important to note that this is a reversible condition and usually resolves once the lenses are removed and the eyes have had time to recover.

A myope will need more power with spectacles than contact lenses because spectacles are positioned further from the eye, resulting in a greater need for corrective power. The "edge lift" with rigid lenses allows for tear exchange and better capillary attraction, which improves comfort and overall eye health.

The given answer is correct because it includes two true statements. The first statement states that the contact lens case should be replaced every 1-3 months, which is important for maintaining good hygiene and preventing the buildup of bacteria. The second statement advises using mild soaps without certain ingredients for insertion or removal of contact lenses, which helps to avoid irritation or damage to the eyes.