Definition and Classification of Low Vision — MCQs
What does a visual acuity test primarily assess?
A 50-year-old patient has difficulty reading close objects. Likely diagnosis?
A patient complains of an inability to read a newspaper, particularly in bright sunlight. What is the most likely diagnosis?
According to WHO ICD-11 classification, visual impairment in the better eye (with best correction) begins at a visual acuity worse than:
Which finding excludes BIRADS 3 categorization?
Which of the following is the platinum-based chemotherapeutic agent used as first-line treatment for ovarian carcinoma?
What is the classification of intelligence corresponding to an IQ score of 90-109?
Which of the following statements about conjunctival lesions is NOT true?
What is the WHO definition of blindness?
Semantic memory includes all except:
Definition and Classification of Low Vision Indian Medical PG Practice Questions and MCQs
Question 1: What does a visual acuity test primarily assess?
- A. Ability to perceive light
- B. Ability to differentiate colors
- C. Ability to recognize shapes and details (Correct Answer)
- D. Ability to detect contrast
Explanation: ***Ability to recognize shapes and details*** - A visual acuity test, typically using a **Snellen chart**, measures the sharpness of vision, specifically the ability to discern letters or symbols at a given distance. - It assesses the eye's capacity to resolve fine **spatial detail**, which is crucial for tasks like reading and recognizing faces. - This is the fundamental definition of visual acuity and what these tests are specifically designed to measure. *Ability to perceive light* - This refers to **light perception (LP)**, the most basic form of vision, indicating whether a person can detect the presence or absence of light. - While essential for vision, it is a much simpler function than what visual acuity tests measure and is assessed separately. *Ability to differentiate colors* - This is assessed by **color vision tests**, such as the Ishihara plates, which evaluate the function of cone photoreceptors. - It specifically checks for **color blindness** (e.g., red-green or blue-yellow deficiencies) and is distinct from the sharpness of vision. *Ability to detect contrast* - This is measured by **contrast sensitivity tests**, which evaluate the ability to distinguish objects from their background at various contrast levels. - While related to overall visual quality, it is a different aspect of vision than the ability to recognize fine details at high contrast.
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 patient complains of an inability to read a newspaper, particularly in bright sunlight. What is the most likely diagnosis?
- A. Nuclear cataract
- B. Cortical cataract
- C. Posterior subcapsular cataract (Correct Answer)
- D. Congenital cataract
Explanation: ***Posterior subcapsular cataract*** - This type of cataract causes significant **glare** and **photophobia**, making it difficult to read in bright light due to opacities located at the **posterior lens capsule**. - The patient experiences worsening vision in **bright light** conditions because the constricted pupil directs more light through the **central posterior opacity**, which lies directly in the visual axis. *Nuclear cataract* - Patients with **nuclear cataracts** typically experience **myopic shift** and improved near vision (second sight) due to increased refractive power of the lens. - Vision is usually worse in **dim light** conditions because of pupillary dilation, which allows more light to pass through the central opacity. *Cortical cataract* - Characterized by **spoke-like opacities** that start in the periphery and extend inward. - While it can cause glare, vision often remains good until the opacities encroach upon the **visual axis**, and it doesn't specifically cause worsening vision in bright light to the same degree as PSC. *Congenital cataract* - Present at birth or shortly after, and symptoms depend on the density and location of the opacity. - While it affects vision, the specific complaint of difficulty reading in bright sunlight is not a typical distinguishing feature of **congenital cataracts**.
Question 4: According to WHO ICD-11 classification, visual impairment in the better eye (with best correction) begins at a visual acuity worse than:
- A. 6/60
- B. 6/36
- C. 6/12 (Correct Answer)
- D. 6/24
Explanation: ***6/12*** - According to the **WHO ICD-11 classification**, visual impairment begins when visual acuity is **less than 6/12** in the better eye with best correction. - This threshold marks the beginning of **mild visual impairment** (visual acuity < 6/12 to ≥ 6/18). - Visual acuity of 6/12 or better is considered **normal vision** without significant impairment. *6/24* - Visual acuity of **6/24** falls within the **moderate visual impairment** category (< 6/18 to ≥ 6/60). - This represents established visual impairment but is not the threshold where impairment begins. *6/36* - Visual acuity of **6/36** also falls within the **moderate visual impairment** range. - This indicates more significant vision loss than the threshold that defines the beginning of visual impairment. *6/60* - Visual acuity of **6/60 or worse** (< 6/60 to ≥ 3/60) is classified as **severe visual impairment**. - Visual acuity worse than 3/60 is classified as **blindness**. - This represents much more severe vision loss than the initial threshold for visual impairment.
Question 5: Which finding excludes BIRADS 3 categorization?
- A. Normal lymph node
- B. Simple cyst
- C. Architectural distortion (Correct Answer)
- D. Focal asymmetry
Explanation: ***Architectural distortion*** - **Architectural distortion** refers to a disruption of the normal breast parenchymal architecture in the absence of a discrete mass, often indicating an underlying malignancy. - This finding is suspicious enough to warrant a recommendation of **biopsy (BI-RADS 4 or 5)**, thus **excluding BI-RADS 3**, which implies a probably benign finding with a low likelihood of malignancy (<2%). - Architectural distortion has a high association with malignancy and cannot be categorized as BI-RADS 3. *Normal lymph node* - A **normal lymph node** within the breast or axilla is a common and benign finding, characterized by an oval shape, fatty hilum, and thin cortex. - Its presence does not increase the suspicion of malignancy and is classified as **BI-RADS 1 or 2** (definitely benign). - This does NOT exclude BI-RADS 3; it is simply a more benign finding. *Simple cyst* - A **simple cyst** is a very common and benign fluid-filled sac, readily identifiable by clear sonographic criteria (anechoic, thin smooth walls, posterior acoustic enhancement). - It is classified as **BI-RADS 2** (benign finding), meaning it is definitely not malignant. - This does NOT exclude BI-RADS 3; it is simply a more benign finding that does not require follow-up. *Focal asymmetry* - **Focal asymmetry** refers to an area of fibroglandular tissue that is visible on only one mammographic projection or is less conspicuous than a mass. - If it has **no associated suspicious features**, it can be appropriately categorized as **BI-RADS 3**, requiring short interval follow-up. - This does NOT exclude BI-RADS 3 categorization.
Question 6: Which of the following is the platinum-based chemotherapeutic agent used as first-line treatment for ovarian carcinoma?
- A. Cyclophosphamide
- B. Methotrexate
- C. Cisplatin (Correct Answer)
- D. Dacarbazine
Explanation: ***Cisplatin*** - **Cisplatin** is a platinum-based chemotherapy drug that forms **DNA cross-links**, inhibiting DNA synthesis and leading to the death of rapidly dividing cells, making it highly effective against **ovarian carcinoma**. - It is a cornerstone of chemotherapy regimens for ovarian cancer, often used in combination with other agents such as paclitaxel. *Methotrexate* - **Methotrexate** is an **antimetabolite** that inhibits dihydrofolate reductase, thereby interfering with DNA synthesis. - While it is used in various cancers like leukemia, lymphoma, and some solid tumors (e.g., breast cancer, gestational trophoblastic disease), it is **not a primary recommended drug for ovarian carcinoma**. *Cyclophosphamide* - **Cyclophosphamide** is an **alkylating agent** that causes DNA damage, leading to cell death. - It is used in many cancers, including lymphoma, breast cancer, and some leukemias, but it is **not a first-line or primary agent for ovarian carcinoma** in contemporary treatment guidelines. *Dacarbazine* - **Dacarbazine** is an **alkylating agent** primarily used in the treatment of **malignant melanoma** and Hodgkin lymphoma. - It is **not indicated for the treatment of ovarian carcinoma**.
Question 7: What is the classification of intelligence corresponding to an IQ score of 90-109?
- A. Below average
- B. Average (Correct Answer)
- C. Slightly below average
- D. Above average
Explanation: ***Average*** - An **IQ score** range of **90-109** is traditionally classified as **Average** intelligence. - This range represents the **mean** and surrounding **standard deviation** of IQ scores in the general population. *Below average* - This classification usually corresponds to IQ scores in the range of **70-79** or **80-89**, depending on the specific scale. - It does not represent the central tendency of the population's intelligence. *Slightly below average* - This category typically corresponds to IQ scores in the range of **80-89**. - It falls just below the average range but is not as low as the "below average" classification. *Above average* - This classification is typically assigned to IQ scores that are in the range of **110-119** or higher. - It signifies cognitive abilities that are greater than the majority of the population.
Question 8: Which of the following statements about conjunctival lesions is NOT true?
- A. Arise from any part of conjunctiva
- B. Can cause Astigmatism
- C. Surgery is treatment of choice (Correct Answer)
- D. UV exposure is risk factor
Explanation: ***Surgery is treatment of choice*** - While surgery can be used to treat conjunctival lesions, it is not always the **treatment of choice**, especially for smaller, asymptomatic lesions like **pinguecula** which may only require observation and lubrication. - Many conjunctival lesions, such as uncomplicated **pterygium** or **pinguecula**, are managed conservatively unless they cause significant symptoms, vision impairment, or cosmetic concerns. *Arise from any part of conjunctiva* - **Conjunctival lesions** can indeed arise from various parts of the conjunctiva, including the palpebral, bulbar, and forniceal conjunctiva. - For example, **pterygium** typically arises from the bulbar conjunctiva, while **pinguecula** also originates in the bulbar conjunctiva, specifically in the interpalpebral fissure. *Can cause Astigmatism* - Larger **conjunctival lesions**, particularly a **pterygium** that encroaches onto the cornea, can induce or alter astigmatism. - The growth of the lesion can change the **curvature of the cornea**, leading to optical distortion and astigmatism. *UV exposure is risk factor* - **Ultraviolet (UV) light exposure** is a well-established risk factor for the development of many conjunctival lesions, including **pterygium** and **pinguecula**. - Chronic UV exposure leads to **elastotic degeneration** of the conjunctival collagen and is thought to play a key role in the pathogenesis of these growths.
Question 9: What is the WHO definition of blindness?
- A. visual acuity less than 6/60 or its equivalent
- B. visual acuity less than 3/60 or its equivalent (Correct Answer)
- C. visual acuity less than 6/18 or its equivalent
- D. visual acuity less than 1/60 or its equivalent
Explanation: ***Visual acuity less than 3/60 or its equivalent*** - The **WHO definition of blindness** refers to a **presenting visual acuity** of less than 3/60 (or 20/400) in the better eye, or a **visual field** of less than 10 degrees from the point of fixation. - This threshold signifies severe visual impairment that meets the criteria for legal or public health definitions of blindness. - The 3/60 criterion is the internationally recognized standard for defining blindness in epidemiological and public health contexts. *Visual acuity less than 6/60 or its equivalent* - This level of vision typically falls under the category of **severe visual impairment** or **low vision** according to WHO classification, not blindness. - While it represents significant visual loss, it is considered less severe than the 3/60 threshold used for defining blindness. *Visual acuity less than 6/18 or its equivalent* - A visual acuity of less than 6/18 is generally considered **moderate visual impairment** or **low vision**, not blindness. - This level of vision implies difficulty with standard visual tasks but is typically not severe enough to be classified as blindness. *Visual acuity less than 1/60 or its equivalent* - This visual acuity is indeed very poor and would certainly be classified as blindness, but it is **more severe** than the WHO definition threshold. - The 3/60 threshold is the specific cutoff point; while 1/60 indicates blindness, it is not the definition itself.
Question 10: Semantic memory includes all except:
- A. Rules
- B. Language
- C. Events (Correct Answer)
- D. Words
Explanation: ***Events*** - **Episodic memory** is the type of long-term memory that stores information about specific **personal events** and experiences, complete with their contextual details like time and place. - Semantic memory, in contrast, involves general facts and knowledge, decoupled from specific personal experiences. *Rules* - **Semantic memory** encompasses our understanding of operating principles and **general truths**, such as the laws of physics or social conventions. - This abstract knowledge about how things work or are structured is a core component of semantic memory. *Language* - The understanding of **vocabulary**, **grammar**, and syntax necessary for communication is a key aspect of semantic memory. - This includes knowledge of word meanings, relationships between words, and how to construct grammatically correct sentences. *Words* - The meaning and definition of individual **words** are stored within **semantic memory**. - This allows us to comprehend spoken and written language and to use words appropriately in context.
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