Contact Lenses for Presbyopia — MCQs
Scleral Expansion Bands are used in the management of:
A 50-year-old patient has difficulty reading close objects. Likely diagnosis?
A 15-year-old girl with myopic astigmatism does not want to wear glasses. What is the best alternative for her?
65-year-old person with hearing loss with normal speech discrimination is suffering from?
Maximum correction of myopia can be done by?
A lady wants LASIK surgery for her daughter and asks for your opinion. All the following are suitable for performing LASIK surgery except:
A patient with contact lens use for the past 2 years presents with the ocular findings shown in the image below. What is the most probable diagnosis?
The following spectacle is used in? (AIIMS Nov 2018)
A 23-year-old woman is diagnosed with chlamydia. Her partner refuses testing. What contact tracing approach is most appropriate?
What is the minimum contact period required for effective chlorination of drinking water?
Contact Lenses for Presbyopia Indian Medical PG Practice Questions and MCQs
Question 1: Scleral Expansion Bands are used in the management of:
- A. Astigmatism
- B. Keratoconus
- C. Presbyopia (Correct Answer)
- D. Myopia
Explanation: ***Presbyopia*** - **Scleral expansion bands** are a surgical treatment strategy designed to restore the eye's ability to accommodate by altering the biomechanics of the sclera and ciliary body. - They aim to improve the range of motion of the ciliary body, thereby allowing the **lens to change shape** more effectively for near vision in **presbyopic** patients. *Astigmatism* - **Astigmatism** is primarily caused by an **irregularly shaped cornea** or lens, leading to blurred vision at all distances. - It is typically managed with corrective lenses (glasses or contact lenses) or refractive surgeries like **LASIK** or **PRK**, which reshape the cornea. *Keratoconus* - **Keratoconus** is a progressive eye disease where the **cornea thins** and bulges into a cone-like shape, causing distorted vision. - Treatments include rigid gas permeable contact lenses, **corneal collagen cross-linking** to halt progression, and in severe cases, corneal transplant. *Myopia* - **Myopia**, or nearsightedness, occurs when the eye focuses images in front of the retina, often due to an **elongated eyeball** or excessive corneal curvature. - It is commonly corrected with concave lenses, contact lenses, or refractive surgeries such as **LASIK** or **PRK** to flatten the cornea.
Question 2: A 50-year-old patient has difficulty reading close objects. Likely diagnosis?
- A. Hypermetropia
- B. Astigmatism
- C. Myopia
- D. Presbyopia (Correct Answer)
Explanation: ***Presbyopia*** - This condition is characterized by the **loss of elasticity** in the lens of the eye, which occurs naturally with age, making it difficult to focus on **near objects**. - Its typical presentation, as seen in this 50-year-old patient, is **difficulty reading close objects** or performing other tasks requiring near vision. *Hypermetropia* - Often causes **farsightedness**, meaning distant objects are seen clearly, but near objects appear blurry due to the eye attempting to constantly accommodate. - While it can make near vision difficult, it is not primarily an age-related loss of accommodation and can affect individuals of various ages. *Astigmatism* - Results from an **irregular curvature of the cornea or lens**, causing blurred or distorted vision at all distances, rather than specifically difficulty with close objects. - This condition makes it difficult for the eye to focus light uniformly on the retina, leading to multiple focal points or streaks. *Myopia* - This is commonly known as **nearsightedness**, where distant objects appear blurry while near objects are seen clearly. - It occurs when the eyeball is too long or the cornea is too steeply curved, causing light to focus in front of the retina.
Question 3: A 15-year-old girl with myopic astigmatism does not want to wear glasses. What is the best alternative for her?
- A. LASIK
- B. Spherical Specs
- C. Contact lenses (Toric) (Correct Answer)
- D. FEMTO Lasik
Explanation: ***Contact lenses (Toric)*** - **Toric contact lenses** are specifically designed to correct **astigmatism**, along with myopia or hyperopia, by having different refractive powers in different meridians. - They offer a non-surgical alternative to glasses, addressing the patient's desire not to wear spectacles, and are generally safe and effective for teenagers. *LASIK* - **LASIK (Laser-Assisted In Situ Keratomileusis)** is a surgical procedure to correct refractive errors, but it is not typically recommended for individuals under **18-21 years of age** due to continued eye growth and refractive changes. - The patient's age of 15 makes her an unsuitable candidate for LASIK at this time. *Spherical Specs* - **Spherical spectacles** are designed to correct myopia or hyperopia but cannot adequately correct **astigmatism**, which is a significant component of this patient's refractive error. - The patient also explicitly states she does not want to wear glasses, making this option undesirable. *FEMTO Lasik* - **FEMTO LASIK** is an advanced form of LASIK that uses a femtosecond laser to create the corneal flap, offering higher precision and safety. - However, similar to traditional LASIK, it is a **refractive surgical procedure** and typically not performed on patients younger than **18 years old** due to ongoing eye development.
Question 4: 65-year-old person with hearing loss with normal speech discrimination is suffering from?
- A. Noise induced hearing loss
- B. Presbycusis (Correct Answer)
- C. Ototoxic drug
- D. NOHL
Explanation: ***Presbycusis*** - **Presbycusis**, or age-related hearing loss, is characterized by a gradual, symmetrical, **sensorineural hearing loss** primarily affecting high frequencies. - Importantly, **speech discrimination** is typically preserved in the early and moderate stages of presbycusis, which aligns with the normal speech discrimination in a 65-year-old. *Noise induced hearing loss* - **Noise-induced hearing loss** is caused by exposure to loud noise and often presents with a characteristic **4 kHz notch** in the audiogram. - While it can cause sensorineural hearing loss, it's not exclusively defined by the age-related onset and might involve more significant **speech discrimination difficulties** depending on the severity and frequency range affected. *Ototoxic drug* - Hearing loss due to **ototoxic drugs** (e.g., aminoglycosides, cisplatin) typically manifests as a **bilateral, high-frequency sensorineural hearing loss** that can progress rapidly. - The history of **drug exposure** would be a key differentiating factor, and while speech discrimination can be affected, the lack of other specific details makes this less likely without further information. *NOHL* - **NOHL** is not a standard, recognized medical acronym for a specific type of hearing loss. - This option is likely a distractor and does not represent a known diagnosis fitting the described clinical picture.
Question 5: Maximum correction of myopia can be done by?
- A. Radial keratotomy
- B. LASIK (Correct Answer)
- C. Photorefractive keratectomy
- D. Orthokeratology
Explanation: ***LASIK*** - **LASIK (Laser-Assisted In Situ Keratomileusis)** allows for significant correction of high myopia by reshaping the cornea with an excimer laser. - It involves creating a **corneal flap** and then ablating tissue underneath, offering precise and stable vision correction for a wide range of refractive errors. - Among the given corneal refractive procedures, LASIK can correct myopia up to **-10 to -12 D**. *Radial keratotomy* - **Radial keratotomy (RK)** involves making radial incisions in the cornea to flatten it, primarily used for low to moderate myopia (up to -3 to -4 D). - It has a higher risk of **unpredictable outcomes**, induced astigmatism, and glare compared to modern laser procedures. *Photorefractive keratectomy* - **Photorefractive keratectomy (PRK)** involves direct ablation of the corneal surface without creating a flap, which is suitable for moderate myopia (up to -8 to -10 D). - While effective, PRK typically has a **longer recovery period** and more post-operative pain than LASIK. *Orthokeratology* - **Orthokeratology (Ortho-K)** uses specially designed rigid contact lenses worn overnight to temporarily reshape the cornea and correct myopia. - The effect is **temporary**, requiring continuous lens wear to maintain vision correction, and is generally limited to low to moderate myopia (up to -4 to -6 D).
Question 6: A lady wants LASIK surgery for her daughter and asks for your opinion. All the following are suitable for performing LASIK surgery except:
- A. Stable refraction for 1 year
- B. Corneal thickness of 600 microns
- C. Myopia of 4 Diopters
- D. Age of 15 years (Correct Answer)
Explanation: ***Age of 15 years*** - LASIK surgery is generally not recommended for individuals under the age of 18-21 years because their **refractive error** may still be changing. - **Refractive stability** is a critical prerequisite to ensure a lasting surgical outcome. *Myopia of 4 Diopters* - This level of **myopia** (nearsightedness) typically falls within the treatable range for LASIK, which can correct moderate to high degrees of refractive error. - LASIK is highly effective for reducing or eliminating dependence on **glasses or contact lenses** for this range. *Stable refraction for 1 year* - **Refractive stability** is an essential criterion for LASIK candidacy, indicating that the patient's prescription has not significantly changed over a specific period. - This ensures that the surgical correction will be durable and accurate, preventing the need for future enhancements due to progression of refractive error. *Corneal thickness of 600 microns* - A **corneal thickness** of 600 microns is considered adequate for LASIK, as it allows for sufficient residual stromal bed thickness after ablation. - The minimum required **residual stromal bed thickness** is typically around 250-300 microns to maintain corneal integrity and prevent ectasia.
Question 7: A patient with contact lens use for the past 2 years presents with the ocular findings shown in the image below. What is the most probable diagnosis?
- A. Trachoma
- B. Giant Papillary conjunctivitis (Correct Answer)
- C. Ocular Surface Squamous Neoplasia (OSSN)
- D. Vernal Keratoconjunctivitis
Explanation: ***Giant Papillary conjunctivitis*** - The image shows **large, elevated papillae** on the **tarsal conjunctiva**, which are characteristic findings of giant papillary conjunctivitis. - This condition is common among **contact lens wearers**, caused by chronic mechanical irritation and an allergic response to lens material or deposits. *Trachoma* - Trachoma is a **chronic infectious disease** caused by *Chlamydia trachomatis*, leading to scarring of the conjunctiva. - It typically presents with **follicles** in the early stages, followed by **scarring** and **pannus formation**, not the large papillae seen here. *Ocular Surface Squamous Neoplasia (OSSN)* - OSSN refers to a spectrum of conditions from **dysplasia to squamous cell carcinoma** affecting the conjunctiva or cornea. - It usually presents as a **gelatinous, fleshy, or leukoplakic lesion**, often at the limbus, which is distinct from the diffuse papillae shown. *Vernal Keratoconjunctivitis* - Vernal keratoconjunctivitis (VKC) is a **severe form of allergic conjunctivitis** but primarily affects children and young adults with a history of atopy. - While it can cause large papillae (cobblestone papillae), it is not specifically associated with contact lens wear and usually has other systemic allergic manifestations.
Question 8: The following spectacle is used in? (AIIMS Nov 2018)
- A. Progressive glasses for presbyopia
- B. Bifocal glasses for presbyopia (Correct Answer)
- C. Bifocals for paediatric pseudo-phakia
- D. Bifocals for adult aphakia
Explanation: ***Bifocal glasses for presbyopia*** - The image clearly shows spectacle lenses with a visible **horizontal line separating two distinct optical powers**, which is characteristic of **bifocal lenses**. - **Presbyopia** is the condition where the eye's lens loses its ability to focus on near objects, requiring a different optical correction for near vision separate from distance vision, precisely what bifocals provide. *Progressive glasses for presbyopia* - **Progressive lenses** offer a gradual change in optical power from distance to near vision without a visible dividing line, unlike the spectacles shown. - They provide a continuous range of focus, but the absence of a visible segment in progressive lenses differentiates them from bifocals. *Bifocals for paediatric pseudo-phakia* - While pediatric pseudophakia (presence of an intraocular lens in a child) might require bifocals, the question asks for the primary use of the *pictured* bifocals, which commonly address **age-related presbyopia**. - Additionally, pseudophakia itself doesn't inherently imply a need for bifocals unless there's an accommodative issue, which is more typically associated with adult presbyopia. *Bifocals for adult aphakia* - **Aphakia** is the absence of the natural lens in the eye, which requires strong corrective lenses. While bifocals can be used in aphakia to provide both distance and near correction, the pictured bifocals are a standard design most commonly associated with correcting **presbyopia** in the general population. - Aphakic corrections generally involve much higher power lenses, which might appear thicker or have different characteristics than the standard bifocal shown.
Question 9: A 23-year-old woman is diagnosed with chlamydia. Her partner refuses testing. What contact tracing approach is most appropriate?
- A. Expedited partner therapy (Correct Answer)
- B. Patient referral only
- C. Contract referral
- D. Provider referral only
Explanation: ***Expedited partner therapy (EPT)*** - This approach allows clinicians to provide medication or a prescription for a partner without a prior medical examination, facilitating treatment when a partner is unwilling or unable to seek care. - It is particularly useful for **chlamydia** and **gonorrhea** to reduce reinfection rates and further transmission. - **Recommended by CDC and WHO** for STI partner management when partners are unlikely to present for care. - *Note: EPT implementation varies by country; in India, partner notification with clinical evaluation is standard practice, but EPT represents the most direct approach when partners refuse testing.* *Patient referral only* - Relying solely on the patient to inform and encourage their partner to seek testing and treatment can be effective but carries a risk of the partner not following through, leading to continued transmission. - This method might be less successful if the partner is uncooperative or unwilling to get tested, as is implied in this scenario. - **Most commonly used approach** in resource-limited settings but has lower success rates. *Contract referral* - Involves the patient agreeing to notify their partner, with the understanding that if the partner does not present for treatment within a specified timeframe, health officials will then intervene. - While it offers a backup, it still relies on initial patient action and may not be immediate enough when a partner is actively refusing testing. - Provides a **safety net** but involves delays in partner treatment. *Provider referral only* - This method involves a healthcare provider directly contacting the partner to inform them of exposure and recommend testing and treatment, respecting patient confidentiality. - This option is generally preferred when there are concerns about the patient's safety or if the patient is unable or unwilling to notify their partner. - More resource-intensive and requires **trained health workers** for partner notification, but ensures partners are reached even if the index patient cannot or will not inform them.
Question 10: What is the minimum contact period required for effective chlorination of drinking water?
- A. 2 hrs
- B. 4 hrs
- C. 1 hour
- D. 30 minutes (Correct Answer)
Explanation: ***30 minutes*** - A minimum **contact period of 30 minutes** is generally recommended for effective chlorination to sufficiently inactivate most pathogenic microorganisms in drinking water. - This duration allows for adequate time for the **chlorine residual** to penetrate and destroy bacterial and viral structures. *1 hour* - While a longer contact time like 1 hour would be effective, it is not the **minimum required** for practical purposes and might lead to increased operational costs or complexity without significant additional benefit in typical scenarios. - Exceeding the minimum contact time can sometimes lead to the formation of **disinfection byproducts**, although this is more dependent on chlorine concentration and water composition. *2 hrs* - A contact time of 2 hours significantly exceeds the **minimum effective period** for most disinfection needs. - Such extended contact times are usually only considered in specific situations with highly resistant pathogens or particular water quality challenges, or when using **lower chlorine doses**. *4 hrs* - A 4-hour contact period is far beyond the **standard minimum** for effective chlorination of drinking water. - Such long contact times are typically impractical for municipal water treatment and could potentially increase the risk of forming **undesirable disinfection byproducts** if not carefully managed.
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