Rehabilitation Strategies — MCQs
Which of the following is the first visual field defect in open-angle glaucoma?
What does a visual acuity test primarily assess?
Which drug is generally contraindicated in the management of traumatic hyphema in a patient with sickle cell disease?
According to WHO ICD-11 classification, visual impairment in the better eye (with best correction) begins at a visual acuity worse than:
All of the following conditions are immediate priorities in the WHO's "Vision -2020: The Right to sight" except:
SAFE strategy is for:
Which type of photoreceptor is primarily responsible for color vision?
A 40 year old male has vision of 6/60 in right eye and 3/60 in left eye under NPCB, he will be classified as:-
Campimetry is used to measure:
A patient with visual acuity of less than 6/60 but more than 3/60 in the better eye is considered to have:
Rehabilitation Strategies Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following is the first visual field defect in open-angle glaucoma?
- A. Ring scotoma
- B. Paracentral scotoma (Correct Answer)
- C. Bitemporal hemianopia
- D. Tunnel vision
Explanation: ***Paracentral scotoma*** - This is the **earliest visual field defect** detected in open-angle glaucoma, typically appearing in the **Bjerrum area** (10-20° from fixation). - Most commonly occurs as a **superior or inferior arcuate scotoma** in the nasal field. - Results from damage to the **retinal nerve fiber layer** around the **optic disc**, which is particularly vulnerable to elevated intraocular pressure. - These scotomas respect the **horizontal raphe** and follow the arcuate nerve fiber bundle pattern. *Ring scotoma* - A **ring scotoma** (Bjerrum scotoma) typically occurs later in the progression of glaucoma, when superior and inferior arcuate defects coalesce to form a ring-like pattern. - This represents **advanced glaucomatous damage** and is not an early finding. *Bitemporal hemianopia* - This visual field defect is characteristic of **optic chiasm compression**, commonly due to a **pituitary tumor** or other suprasellar lesions. - It is **not associated with glaucoma**, which causes damage to the optic nerve fibers within the eye, not at the chiasm. *Tunnel vision* - **Tunnel vision** represents severe, **end-stage glaucoma**, where only a small central island of vision remains. - It indicates extensive loss of peripheral visual field and is a late finding, not an early one.
Question 2: 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 3: Which drug is generally contraindicated in the management of traumatic hyphema in a patient with sickle cell disease?
- A. Timolol
- B. Steroids
- C. Acetazolamide (Correct Answer)
- D. Atropine
Explanation: ***Acetazolamide*** - **Acetazolamide** is a **carbonic anhydrase inhibitor** that is **generally contraindicated** in patients with **sickle cell disease or trait**. - It causes **systemic acidosis** by increasing renal bicarbonate excretion, which lowers blood pH. - **Acidosis promotes sickling** of red blood cells, which can lead to **vaso-occlusion**, increased blood viscosity, and potential complications including **anterior chamber obstruction** and **secondary glaucoma**. - Despite its usefulness in lowering intraocular pressure in other settings, this risk makes it contraindicated in sickle cell patients with hyphema. *Timolol* - **Timolol** is a **beta-blocker** that reduces aqueous humor production and is generally **safe and effective** for reducing **intraocular pressure** in traumatic hyphema. - It does not cause systemic acidosis or affect red blood cell sickling. - Commonly used in hyphema management regardless of sickle cell status. *Steroids* - **Topical or systemic steroids** are often used to reduce **inflammation** and anterior chamber reaction in traumatic hyphema. - They help prevent **secondary hemorrhage** and reduce complications. - They do not contribute to red blood cell sickling or systemic acidosis and are safe in sickle cell disease. *Atropine* - **Atropine** is a **cycloplegic agent** used to paralyze the ciliary body and dilate the pupil, which helps **relieve pain** and prevent **posterior synechiae** in hyphema. - It has no adverse effects related to **sickle cell disease** or red blood cell sickling. - Routinely used in hyphema management.
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: All of the following conditions are immediate priorities in the WHO's "Vision -2020: The Right to sight" except:
- A. Cataract
- B. Epidemic conjunctivitis (Correct Answer)
- C. Onchocerciasis
- D. Trachoma
Explanation: ***Epidemic conjunctivitis*** - While **epidemic conjunctivitis** can cause significant discomfort and temporary vision impairment, it is generally **self-limiting** and rarely leads to permanent blindness. - It was not identified as one of the top five global causes of avoidable blindness targeted by the Vision 2020 initiative. *Cataract* - **Cataract** is the **leading cause of blindness** globally, accounting for approximately half of all cases. - It is a highly treatable condition through surgery, making it a critical priority for Vision 2020. *Onchocerciasis* - Also known as **river blindness**, onchocerciasis is a parasitic disease that causes severe visual impairment and blindness. - It is a significant public health problem in several regions, particularly in Africa, and was a key focus of Vision 2020 due to its widespread impact and the availability of preventive chemotherapy. *Trachoma* - **Trachoma** is the **leading infectious cause of blindness** worldwide, caused by *Chlamydia trachomatis*. - Given its preventable and treatable nature, and its prevalence in many impoverished areas, it was designated as one of the priority diseases under Vision 2020.
Question 6: SAFE strategy is for:
- A. Onchocerciasis
- B. Glaucoma
- C. Diabetic retinopathy
- D. Trachoma (Correct Answer)
Explanation: ***Trachoma*** - The **SAFE strategy** is a comprehensive public health approach designed to eliminate **trachoma**, a preventable cause of blindness. - SAFE stands for **Surgery** for trichiasis, **Antibiotics** to treat active infection, **Facial cleanliness** to reduce transmission, and **Environmental improvement** (especially access to water and sanitation) to prevent reinfection. *Onchocerciasia* - This condition, also known as **river blindness**, is primarily managed through mass drug administration of **ivermectin**. - While public health interventions are crucial for onchocerciasis, the specific SAFE acronym is not associated with its control program. *Glaucoma* - The management of glaucoma focuses on lowering **intraocular pressure** through medications, laser treatment, or surgery. - It is a chronic eye condition that does not involve infectious agents like trachoma, and the SAFE strategy is irrelevant. *Diabetic retinopathy* - This complication of diabetes is managed by controlling **blood sugar**, blood pressure, and lipids, along with specific ophthalmological treatments like laser photocoagulation or anti-VEGF injections. - It is a non-infectious, metabolic disease, making the SAFE strategy inapplicable.
Question 7: Which type of photoreceptor is primarily responsible for color vision?
- A. Cones (Correct Answer)
- B. Bipolar cells
- C. Rods
- D. Occipital cortex
Explanation: ***Correct Answer: Cones*** - **Cones** are specialized photoreceptor cells in the retina responsible for **color vision** and **high-acuity vision**. - There are **three types of cones**, each sensitive to different wavelengths of light: **L-cones (red)**, **M-cones (green)**, and **S-cones (blue)**. - This trichromatic system allows for the perception of a wide range of colors through photopic (daylight) vision. *Incorrect: Rods* - **Rods** are photoreceptor cells primarily responsible for **scotopic vision** (vision in low light conditions) and **peripheral vision**. - They contain rhodopsin and do not contribute to color perception, instead detecting differences in light intensity. - Rods are more numerous (~120 million) than cones (~6 million) in the human retina. *Incorrect: Bipolar cells* - **Bipolar cells** are second-order interneurons in the retina that transmit signals from photoreceptors (rods and cones) to ganglion cells. - They play a role in the initial processing of visual information but are **not photoreceptors themselves**. - They do not directly detect light or color. *Incorrect: Occipital cortex* - The **occipital cortex** (visual cortex, area V1-V5) is the brain region responsible for processing visual information, including color perception. - It is **not a photoreceptor** but rather the cortical destination for visual signals. - It receives processed input from the retina via the lateral geniculate nucleus of the thalamus.
Question 8: A 40 year old male has vision of 6/60 in right eye and 3/60 in left eye under NPCB, he will be classified as:-
- A. Socially blind (Correct Answer)
- B. Economically blind
- C. Low vision
- D. Normal
Explanation: ***Socially blind*** - According to the **National Programme for Control of Blindness (NPCB)** criteria, visual acuity of **6/60 in the better eye** falls under the category of **blindness** (specifically, visual acuity <6/60 to 3/60). - The term **"socially blind"** is sometimes used colloquially to describe individuals who meet the medical criteria for blindness but may retain some functional vision. - In this case, the right eye (6/60) is the better eye, and 6/60 vision qualifies as blindness under NPCB guidelines, making "socially blind" the most appropriate classification among the given options. *Low vision* - **Low vision** under NPCB is defined as visual acuity **<6/18 to 6/60** in the better eye with best possible correction. - Since this patient has exactly 6/60 in the better eye, they fall at the threshold between low vision and blindness. - By strict NPCB criteria, **6/60 is classified as blindness**, not low vision (which requires vision better than 6/60). *Economically blind* - This is not a recognized formal classification under NPCB guidelines. - NPCB criteria are based on visual acuity and visual field measurements, not economic considerations. *Normal* - Normal vision is typically 6/6 to 6/9. - Vision of 6/60 and 3/60 is significantly impaired and does not qualify as normal.
Question 9: Campimetry is used to measure:
- A. Squint
- B. Field of Vision (Correct Answer)
- C. Pattern of retina
- D. Malignant melanoma
Explanation: ***Field of Vision*** - **Campimetry** is a diagnostic test specifically designed to map and assess a person's **field of vision**, identifying blind spots or areas of diminished sight. - This technique is crucial for detecting and monitoring conditions that affect the optic nerve or visual pathways, such as **glaucoma** or neurological disorders. *Squint* - A **squint**, also known as strabismus, refers to a misalignment of the eyes. - Its assessment primarily involves tests of **ocular motility** and alignment, such as the cover test, rather than perimetry. *Pattern of retina* - The **pattern of the retina** is evaluated through direct visualization using an **ophthalmoscope** or other retinal imaging techniques like fundus photography or optical coherence tomography (OCT). - These methods provide structural information about the retina, not its functional visual field. *Malignant melanoma* - **Malignant melanoma** (in the context of the eye) is a tumor that can affect various parts of the eye, including the choroid, iris, or conjunctiva. - Its diagnosis involves clinical examination, imaging studies (**ultrasound**, OCT, **fluorescein angiography**), and sometimes biopsy, not primarily visual field testing.
Question 10: A patient with visual acuity of less than 6/60 but more than 3/60 in the better eye is considered to have:
- A. Economical blindness (Correct Answer)
- B. Social blindness
- C. Legal blindness
- D. Absolute blindness
Explanation: ### Explanation **1. Why Economical Blindness is Correct:** In ophthalmology, **Economical Blindness** is defined as visual acuity of **less than 6/60 but better than or equal to 3/60** in the better eye with best possible correction. This threshold is significant because, at this level of vision, an individual is generally unable to perform any work for which eyesight is essential, leading to a loss of earning capacity. **2. Analysis of Incorrect Options:** * **Social Blindness:** This refers to visual acuity of **less than 3/60** in the better eye. At this stage, the individual cannot socially interact or move about independently in a strange environment. * **Legal Blindness:** This is a term used for administrative purposes (like disability benefits). According to the WHO and the National Programme for Control of Blindness (NPCB) India, it is defined as visual acuity **less than 3/60** or a visual field loss of **less than 10 degrees** in the better eye. * **Absolute Blindness:** This is the total absence of sight. Clinically, it is defined as **No Perception of Light (No PL)** in both eyes. **3. NEET-PG High-Yield Pearls:** * **WHO Definition of Blindness:** Visual acuity < 3/60 or visual field < 10° in the better eye. * **NPCB India Definition (Revised):** To align with WHO, India now defines blindness as visual acuity **< 3/60** (previously it was < 6/60). * **Low Vision:** Visual acuity between **< 6/18 and 3/60** in the better eye. * **One-Eyed Person:** If the vision in one eye is 6/6 and the other is No PL, the person is **not** considered blind by WHO/NPCB standards as the better eye is used for classification.
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