A patient with visual acuity of less than 6/60 but more than 3/60 in the better eye is considered to have:
Visual acuity of 6/60 is classified as?
Which of the following best defines blindness?
A person is not able to count fingers from a distance of 6 meters. He shall be categorized into which type of blindness?
Minimum visual acuity below which a person is called Blind
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 patient with age-related macular degeneration complains of difficulty reading despite using glasses. Which assistive device is most appropriate to enhance their reading ability?
According to the WHO, what is the minimum distance at which a person is considered blind if they cannot count fingers in daylight?
According to the World Health Organization, blindness is defined as counting fingers at a distance of what?
According to WHO ICD-11 classification, visual impairment in the better eye (with best correction) begins at a visual acuity worse than:
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.
Explanation: ### Explanation The classification of visual impairment is based on the **WHO (World Health Organization)** criteria, which are high-yield for NEET-PG. **1. Why Option A is Correct:** According to the WHO classification (ICD-10), **Low Vision** is defined as visual acuity of **less than 6/18 but equal to or better than 3/60** in the better eye with best possible correction. Since 6/60 falls within this range, it is categorized as low vision. Additionally, a visual field of less than 20 degrees around central fixation also qualifies as low vision, even if acuity is better. **2. Why the other options are incorrect:** * **Option B (Normal vision):** Normal visual acuity is defined as **6/6 or better**. Vision between 6/6 and 6/18 is considered "Mild or No Visual Impairment." * **Option C (Blindness):** Under WHO criteria, **Blindness** is defined as visual acuity **worse than 3/60** (less than 3/60 to no light perception) or a visual field of less than 10 degrees in the better eye. * **Option D (Visual morbidity):** This is a general term referring to any visual loss that interferes with daily activities; it is not a formal WHO classification category for specific acuity levels. **Clinical Pearls for NEET-PG:** * **NPCB (National Programme for Control of Blindness - India) Criteria:** Note that India previously used <6/60 as the cutoff for blindness to prioritize surgical backlogs, but it has now aligned with WHO criteria (**<3/60**) to match global standards. * **Categories of Impairment:** * Category 1 (Moderate): <6/18 to 6/60 * Category 2 (Severe): <6/60 to 3/60 * Category 3, 4, 5: Blindness (starting from <3/60) * **Visual Field:** Remember that a field of **<10°** is the threshold for blindness, regardless of Snellen acuity.
Explanation: ***Visual acuity less than 3/60 in the better eye after best possible correction*** - This defines **blindness** according to the **WHO/ICD-11 classification** (Category 3 and 4). - VA < 3/60 to 1/60 is **Category 3 blindness**, and VA < 1/60 to light perception is **Category 4 blindness**. - This is the internationally accepted standard definition of blindness. *Visual acuity less than 6/60 in the better eye* - In **India**, the National Programme for Control of Blindness and Visual Impairment (NPCB&VI) defines blindness as VA < 6/60 in the better eye with best correction. - However, the **WHO international standard** uses the more stringent criterion of < 3/60. - For global standardization and comparison, the **WHO definition (< 3/60)** is considered the primary reference. *Visual field less than 10 degrees from fixation in the better eye* - This is an **alternative criterion** for defining blindness according to WHO guidelines. - A person with VF < 10° (or < 20° in some definitions) is considered legally blind even if VA is better than 3/60. - Both VA and VF criteria are valid, but the question asks for the "best" single definition, where the **VA criterion** is most commonly cited. *Inability to perceive light in both eyes* - This represents **No Light Perception (NLP)** or **total blindness** (WHO Category 5). - This is the most severe form of blindness but is too restrictive as a general definition, as it excludes individuals with light perception or minimal vision who are still legally and functionally blind.
Explanation: ***Severe visual impairment*** - Severe visual impairment is defined as visual acuity **less than 6/60 to 3/60** (presenting visual acuity). - The key clinical threshold is the **inability to count fingers at 6 meters**, which corresponds to VA < 6/60. - This category represents a significant functional vision loss where the person can typically still count fingers at 3 meters but not at 6 meters. - According to **WHO ICD-10 classification**, this falls under **Category H1** (severe visual impairment). *Moderate visual impairment* - Moderate visual impairment is characterized by visual acuity of **less than 6/18 to 6/60**. - A person with moderate visual impairment would **still be able to count fingers at 6 meters**. - This does not match the clinical presentation described in the question. *Profound visual impairment* - Profound visual impairment (also called **Blindness Category 1**) is defined as visual acuity **less than 3/60 to 1/60**. - The key threshold here is the **inability to count fingers at 3 meters** (but can count at 1 meter). - This is more severe than what is described in the question, as the question only specifies inability at 6 meters. *Near-total blindness* - Near-total blindness (**Blindness Category 2**) refers to visual acuity **less than 1/60 to light perception only**. - This represents the ability to perceive hand movements close to the face or only light perception. - This is far more severe than the presentation described in the question.
Explanation: ***3/60*** - This is the **WHO and Indian definition threshold for legal blindness** - visual acuity of 3/60 or worse in the better eye with best possible correction - This means seeing at 3 meters what a person with normal vision sees at 60 meters - Visual acuity **below 3/60** (i.e., 3/60 or worse) qualifies as blind - This is the internationally recognized standard used in **NEET-PG and Indian ophthalmology practice** *6/60* - Visual acuity of 6/60 represents **severe visual impairment** but NOT blindness - This is above the 3/60 threshold, so does not meet criteria for legal blindness - Classified as "severely visually impaired" rather than blind *2/60* - While 2/60 is definitely blindness (being worse than 3/60), it is NOT the **minimum threshold** - The question asks for the cutoff point, which is 3/60 - This represents a more severe degree of blindness beyond the defining threshold *4/60* - Like 2/60, this is also below the 3/60 threshold and qualifies as blindness - However, it is NOT the standard defining threshold - The established cutoff remains **3/60** per WHO/Indian guidelines
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.
Explanation: ***Magnifying glass*** - **Magnifying glass** is the most appropriate low vision aid for reading in **age-related macular degeneration (ARMD)**. - ARMD causes **central vision loss** (scotoma), making reading difficult despite correct refractive correction. - Magnification devices **enlarge the retinal image**, allowing patients to use their **peripheral retina** to see enlarged text. - Handheld and stand magnifiers are **first-line assistive devices** in low vision rehabilitation for ARMD patients. *Bifocal glasses* - Bifocal glasses correct **presbyopia** (age-related loss of accommodation) for both distance and near vision. - They do **not provide magnification** beyond standard refractive correction. - They cannot compensate for the **central scotoma** caused by macular degeneration. *Contact lenses* - Contact lenses correct **refractive errors** (myopia, hyperopia, astigmatism) but do not magnify. - They offer the same refractive correction as glasses but in a different format. - They do **not address the central vision loss** from ARMD that requires magnification. *Intraocular lens* - **Intraocular lens (IOL)** is implanted during **cataract surgery** to replace the clouded natural lens. - While multifocal IOLs can improve near and distance vision, they do not provide the significant **magnification needed** for severe central vision loss. - IOL implantation is **not a treatment for ARMD**, though patients with ARMD may also have cataracts requiring surgery.
Explanation: ***3 metres*** - The **WHO definition of blindness** includes the inability to count fingers at 3 meters (or 10 feet) in daylight. - This serves as a practical measure for severe **visual impairment** when standard acuity charts are unavailable. *1 metre* - While a significant visual impairment, the inability to count fingers at 1 meter is typically categorized as **severe visual impairment**, not outright blindness, by the WHO. - Severe visual impairment has a slightly less stringent threshold than the definition of blindness. *2 metres* - The inability to count fingers at 2 meters also falls under the category of **severe visual impairment**, according to WHO criteria. - It indicates significant vision loss but is not the specific distance used to define blindness when counting fingers. *4 metres* - A person unable to count fingers at 4 meters would certainly meet the criteria for **blindness**, as this is a greater distance than the 3-meter threshold. - However, the 3-meter mark is the **minimum specified distance** for this particular criterion of blindness by the WHO.
Explanation: ***3 meters*** - The World Health Organization (WHO) defines **blindness** for epidemiological purposes as a best-corrected visual acuity worse than **3/60** or **counting fingers at 3 meters** in the better eye. - This criterion helps in global health surveillance and resource allocation for visual impairment. *1 meter* - Counting fingers at **1 meter** represents a visual acuity of approximately **1/60**, which is **worse than 3/60** and therefore also falls into the **blindness** category. - However, the WHO definition specifically uses **3 meters (3/60)** as the threshold—visual acuity worse than this (including 1/60) confirms blindness, but 3/60 is the defining cut-off point. *6 meters* - Counting fingers at **6 meters** would imply a visual acuity of approximately **6/60**, which is better than the WHO threshold for blindness. - This level of vision falls into the category of **severe visual impairment**, not blindness. *9 meters* - Counting fingers at **9 meters** suggests a relatively better level of visual acuity. - This is significantly above the WHO definition of blindness and would be classified as **moderate visual impairment** or better.
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.
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