Visual Field Testing in Glaucoma — MCQs
Arcuate field defect akin to glaucoma is seen in?
What is the earliest change in glaucoma on perimetry?
A female presents with loss of vision in the right halves of both eyes. Where is the lesion located in the optic pathway?
Which keratometry reading is most accurate in post-LASIK eyes for IOL power calculation?
Fluorescein dye for ophthalmological diagnosis is injected into:
Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
Which of the following is the first visual field defect in open-angle glaucoma?
A 35-year-old lady, Malti, has unilateral headache, nausea, vomiting, and visual blurring. The diagnosis is:
Campimetry is used to measure:
In a patient presenting with an acute unilateral red eye and visual impairment, what is the most likely diagnosis?
Visual Field Testing in Glaucoma Indian Medical PG Practice Questions and MCQs
Question 1: Arcuate field defect akin to glaucoma is seen in?
- A. Optic nerve lesion (Correct Answer)
- B. Pituitary adenoma
- C. Posterior cerebral artery infarct
- D. None of the options
Explanation: ***Optic nerve lesion*** - An **arcuate field defect** is a specific pattern of visual field loss that follows the course of nerve fibers in the retina and is characteristic of **optic nerve damage**, similar to what is seen in glaucoma. - This type of defect is due to damage to the **bundle of retinal nerve fibers** that arch above or below the macula, often causing a scotoma (blind spot) that respects the horizontal meridian. - Common causes include **anterior ischemic optic neuropathy (AION)**, **optic neuritis**, and other optic nerve pathologies that affect the nerve fiber layer. *Pituitary adenoma* - A pituitary adenoma typically causes a **bitemporal hemianopsia** due to compression of the optic chiasm. - This visual field defect involves the lateral halves of both visual fields, which is different from an arcuate defect. *Posterior cerebral artery infarct* - An infarct in the posterior cerebral artery typically leads to a **homonymous hemianopsia** (loss of half of the visual field on the same side in both eyes) or a quadrantanopsia. - This type of defect results from damage to the **visual cortex** or optic radiations, not the optic nerve itself in a glaucoma-like pattern. *None of the options* - This is incorrect because **optic nerve lesion** is a valid and correct answer. - Optic nerve pathologies are well-established causes of arcuate field defects similar to those seen in glaucoma.
Question 2: What is the earliest change in glaucoma on perimetry?
- A. Complete field loss
- B. Isopter contraction + baring of blind spot (Correct Answer)
- C. Tunnel vision defect
- D. Complete vision loss
Explanation: ***Isopter contraction + baring of blind spot*** - Early glaucomatous damage often manifests as an **isopter contraction**, meaning the **visual field narrows** for a given stimulus intensity. - **Baring of the blind spot** occurs when the isopter for a small target contracts inwards, leaving the physiological blind spot exposed to targets that would normally be seen. *Complete field loss* - This is indicative of **very advanced glaucoma**, representing extensive damage to the optic nerve. - It would be preceded by numerous earlier, more subtle visual field defects. *Tunnel vision defect* - **Tunnel vision** is a severe form of visual field constriction, characteristic of **advanced glaucoma** where only the central field of vision remains. - It is not the earliest change as it implies significant peripheral field loss has already occurred. *Complete vision loss* - **Complete vision loss** in an eye signifies end-stage disease, far beyond the earliest changes seen in glaucoma. - It means there is no light perception, indicating total destruction of the optic nerve fibers.
Question 3: A female presents with loss of vision in the right halves of both eyes. Where is the lesion located in the optic pathway?
- A. Left optic tract (Correct Answer)
- B. Optic radiation
- C. Optic chiasma
- D. Right optic tract
Explanation: Left optic tract - A lesion in the **left optic tract** causes **right homonymous hemianopsia**, meaning loss of vision in the right halves of both eyes [1]. - This is because the left optic tract carries visual information from the **nasal retina of the right eye** and the **temporal retina of the left eye**, both of which process the right visual field [1]. *Optic radiation* - A lesion in the optic radiation would also cause a **homonymous hemianopsia** but depending on the specific location within the radiation, it could result in a **quadrantanopia** (loss of a quarter visual field) rather than a complete hemianopsia. - The optic radiation projects from the **lateral geniculate nucleus** to the **visual cortex**, and damage here affects the post-chiasmatic visual pathway [1]. *Optic chiasma* - A lesion at the **optic chiasma** typically results in **bitemporal hemianopsia**, which is the loss of vision in the **temporal halves of both eyes** [1]. - This occurs because the **crossing nasal fibers** from both eyes, which carry information from the temporal visual fields, are affected [1]. *Right optic tract* - A lesion in the **right optic tract** would result in **left homonymous hemianopsia**, meaning loss of vision in the **left halves of both eyes** [1]. - This is due to the right optic tract carrying fibers from the **nasal retina of the left eye** and the **temporal retina of the right eye**, both of which process the left visual field [1].
Question 4: Which keratometry reading is most accurate in post-LASIK eyes for IOL power calculation?
- A. Topography-derived K
- B. Total corneal power (Correct Answer)
- C. Manual keratometry
- D. Automated keratometry
Explanation: ***Total corneal power*** * After LASIK, the **anterior and posterior corneal curvatures** are altered, leading to discrepancies in standard keratometry readings. * **Total corneal power** methods, such as those derived from **corneal tomography** or **anterior segment OCT**, account for both surfaces, providing a more accurate estimation of the true refractive power. * *Topography-derived K* * While corneal topography is valuable for assessing the anterior corneal surface and identifying **irregular astigmatism**, it traditionally focuses on the anterior curvature and may not fully account for the altered **posterior corneal surface** after LASIK. * Standard topography-derived K values often rely on assumptions about the posterior-to-anterior corneal curvature ratio, which are invalid after refractive surgery. * *Manual keratometry* * Manual keratometry measures the **anterior corneal curvature** at a few discrete points and is highly susceptible to inaccuracies due to the post-LASIK changes in corneal shape. * It tends to **overestimate the corneal power** in eyes that have undergone myopic LASIK and **underestimate it** in hyperopic LASIK, leading to significant IOL power calculation errors. * *Automated keratometry* * Similar to manual keratometry, automated keratometry primarily measures the **anterior corneal surface** and relies on a fixed refractive index ratio that is no longer valid after corneal reshaping. * These devices generally provide **inaccurate keratometry readings** in post-refractive surgery eyes, contributing to refractive surprises after cataract surgery.
Question 5: Fluorescein dye for ophthalmological diagnosis is injected into:
- A. Antecubital vein (Correct Answer)
- B. Popliteal vein
- C. Femoral vein
- D. Subclavian vein
Explanation: ***Antecubital vein*** - Fluorescein angiography requires rapid delivery of the dye into the **systemic circulation** for quick visualization of retinal and choroidal vasculature. - The **antecubital vein** is a readily accessible, large superficial vein that allows for quick and efficient intravenous dye injection. *Popliteal vein* - The popliteal vein is located behind the **knee** and is not a standard or practical site for routine intravenous injections, especially when rapid delivery to the eye is needed. - Its location makes it less accessible and potentially more uncomfortable for the patient compared to an arm vein. *Femoral vein* - The femoral vein is a large, deep vein in the **groin**, typically reserved for central venous access or specific procedures due to the increased risk of complications like infection or hematoma. - It is not routinely used for peripheral intravenous injections such as fluorescein, where a more superficial and accessible vein is preferred. *Subclavian vein* - The subclavian vein is a **central vein** located under the clavicle, accessed via a more invasive procedure, usually for central venous catheters or hemodialysis access. - It carries higher risks compared to peripheral venipuncture and is not chosen for simple diagnostic dye injections like fluorescein.
Question 6: Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
- A. Statements 1 & 2 are correct, 2 is not explaining 1 (Correct Answer)
- B. Statements 1 and 2 are correct and 2 is the correct explanation for 1
- C. Statements 1 and 2 are incorrect
- D. Statement 1 is incorrect
Explanation: ***Correct: Statements 1 & 2 are correct, 2 is not explaining 1*** **Analysis of Statement 1:** - A 59-year-old patient with **flaccid bullae** and **suprabasal acantholytic split** on histopathology is the classic presentation of **Pemphigus vulgaris** - The flaccid (easily ruptured) nature of bullae distinguishes it from tense bullae seen in bullous pemphigoid - The suprabasal location of the split (just above the basal layer) with acantholysis (loss of cell-to-cell adhesion) is pathognomonic - **Statement 1 is CORRECT** ✓ **Analysis of Statement 2:** - The **"row of tombstones" or "tombstone appearance"** is indeed a diagnostic histopathological feature of Pemphigus vulgaris - This appearance results from basal keratinocytes remaining attached to the basement membrane while suprabasal cells separate due to acantholysis - The intact basal cells standing upright resemble a row of tombstones - **Statement 2 is CORRECT** ✓ **Does Statement 2 explain Statement 1?** - Statement 2 describes a **histopathological appearance** (tombstone pattern) that is a **consequence** of the suprabasal split - However, it does NOT explain the **underlying cause** of the flaccid bullae or the suprabasal split - The true explanation involves **IgG autoantibodies against desmoglein 3 (and desmoglein 1)**, which attack intercellular adhesion structures (desmosomes), causing **acantholysis** - Therefore, **Statement 2 does NOT explain Statement 1** ✗ *Incorrect: Statement 2 is the correct explanation for Statement 1* - While both statements describe features of Pemphigus vulgaris, the tombstone appearance is a descriptive finding, not an explanatory mechanism *Incorrect: Statements 1 and 2 are incorrect* - Both statements are medically accurate descriptions of Pemphigus vulgaris features *Incorrect: Statement 1 is incorrect* - Statement 1 correctly describes the cardinal clinical and histopathological features of Pemphigus vulgaris
Question 7: 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 8: A 35-year-old lady, Malti, has unilateral headache, nausea, vomiting, and visual blurring. The diagnosis is:
- A. Posterior fossa cyst
- B. Subarachnoid hemorrhage
- C. Glaucoma (Correct Answer)
- D. Cluster headache
Explanation: ***Glaucoma (Acute Angle-Closure)*** - The combination of **unilateral headache**, **nausea**, **vomiting**, and **visual blurring** is highly suggestive of **acute angle-closure glaucoma**. - This condition involves a sudden increase in **intraocular pressure**, which can cause a severe headache, often localized to the affected eye, and systemic symptoms due to vagal stimulation. *Posterior fossa cyst* - A posterior fossa cyst could cause headaches, nausea, and vomiting due to increased **intracranial pressure** or mass effect. - However, it typically presents with **bilateral** or generalized headache and specific neurological deficits related to cerebellar or brainstem compression, not typically unilateral visual blurring as the primary ocular symptom. *Subarachnoid hemorrhage* - A subarachnoid hemorrhage characteristically presents with a **sudden-onset**, severe "thunderclap" headache, often described as the "worst headache of my life." - While it can cause nausea and vomiting, visual blurring is not the primary or unilateral symptom, and the headache rarely gradually progresses as might be implied by "unilateral headache" without further qualification of its onset. *Cluster headache* - Cluster headaches are characterized by **severe unilateral pain**, typically around the eye or temple, accompanied by **autonomic symptoms** like tearing, nasal congestion, and ptosis on the affected side. - While visual blurring can occur, nausea and vomiting are less prominent than in acute glaucoma, and the pain is usually described as excruciating and stabbing, without the significant visual loss.
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: In a patient presenting with an acute unilateral red eye and visual impairment, what is the most likely diagnosis?
- A. Conjunctivitis
- B. Corneal abrasion
- C. Uveitis
- D. Acute angle-closure glaucoma (Correct Answer)
Explanation: ***Acute angle-closure glaucoma*** - This condition presents with a **sudden onset of unilateral red eye**, **severe pain**, and **rapidly progressive visual impairment** due to increased intraocular pressure. - Other symptoms often include **halos around lights**, **nausea**, and **vomiting**. - Classic findings include a **mid-dilated fixed pupil**, **hazy cornea**, and **shallow anterior chamber**. *Conjunctivitis* - While it causes a **red eye**, the primary symptom is usually **itching or foreign body sensation**, not significant pain or severe visual loss. - Vision is typically **unaffected**, or only mildly blurred by discharge. *Corneal abrasion* - This condition would cause a **red eye**, **pain**, and **photophobia**, but the visual impairment is usually **less severe** and localized to the area of abrasion. - It is typically associated with a **history of trauma** or foreign body sensation. *Uveitis* - This can cause a **red eye**, pain, and **photophobia**, with varying degrees of visual impairment, but the onset is typically **subacute or chronic**, and the pain is often described as a **dull ache** rather than the severe pain of acute angle-closure glaucoma. - It often presents with **miosis** and **ciliary flush**.
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