NEET-PG 2012 - Ophthalmology Practice Questions

Q: Child with mild squint. Intrauterine, birth history, developmental history till date all normal. Corneal light reflex normal. All other eye parameters normal except exaggerated epicanthal fold. Diagnosis ?

Pseudostrabismus. ***Pseudostrabismus*** * The presence of **exaggerated epicanthal folds** can create the optical illusion of a child having misaligned eyes, even when the eyes are perfectly straight. * The normal **corneal light reflex** (Hirschberg test) confirms that the eyes are properly aligned, and the perceived "squint" is not a true strabismus. *Exophoria (outward drift)* * This condition involves a **tendency for the eyes to drift outwards**, which would be detected by specific cover/uncover tests. * An outward drift would usually result in an abnormal corneal light reflex, and the exaggerated epicanthal folds would not explain this type of misalignment. *Esophoria (inward drift)* * This is a **tendency for the eyes to drift inwards**, which would also be revealed by tests for phorias and often by an abnormal corneal reflex. * The clinical presentation points away from a true inward deviation, as the corneal reflex is normal. *Accommodative esotropia* * This is a **true inward turning of the eye** (strabismus) that is often linked to uncorrected farsightedness (hyperopia). * It would present with an **abnormal corneal light reflex** and would not be explained solely by epicanthal folds, as it involves actual ocular deviation.

Q: What is the most common orbital tumor in children?

Hemangioma. ***Hemangioma*** - **Capillary hemangioma** is the **most common benign orbital tumor/mass** in children, typically presenting in the first few months of life. - It is characterized by **rapid growth during the first year**, followed by **spontaneous involution** (usually complete by age 5-7 years). - These lesions are composed of rapidly proliferating endothelial cells and can cause **proptosis, ptosis**, and, if large, **amblyopia** due to visual axis obstruction or induced astigmatism. - Management is often conservative (observation) unless vision-threatening, in which case systemic steroids or propranolol may be used. *Nerve sheath tumor* - **Optic nerve sheath meningiomas** and **schwannomas** are rare in children, typically presenting in older adults. - While they can cause visual impairment and proptosis, their incidence in the pediatric population is significantly lower than hemangiomas. *Lymphoma* - **Orbital lymphoma** is exceedingly rare in children and is typically a tumor of adulthood, often associated with systemic lymphoma. - When it does occur in children, it might be a manifestation of a more widespread lymphoproliferative disorder. *Meningioma* - **Meningiomas** generally arise from arachnoid cap cells and are less common in children than in adults. - In children, they are more often associated with **neurofibromatosis type 2** and tend to be more aggressive.

Q: What is the term for an abnormally eccentrically placed pupil?

Corectopia. ***Corectopia*** - **Corectopia** refers to an **abnormally eccentrically placed pupil**, meaning the pupil is displaced from its normal central position within the iris. - This condition can be **congenital** or acquired due to trauma, inflammation, or surgery. *Polycoria* - **Polycoria** is a rare congenital anomaly characterized by the presence of **multiple pupils** in a single iris. - Each pupil typically has its own independent sphincter muscle. *Anisocoria* - **Anisocoria** is the condition where the **pupils are of unequal size**, meaning one pupil is larger or smaller than the other. - This can be physiological (normal) or pathological, indicating underlying neurological or ocular issues. *Ectopia lentis* - **Ectopia lentis** refers to the **displacement or dislocation of the natural lens** of the eye from its normal position. - It is often associated with systemic conditions like **Marfan syndrome** or trauma.

Q: What is the most common cause of anterior uveitis?

Idiopathic. ***Idiopathic*** - In a significant proportion of cases of **anterior uveitis**, a specific cause cannot be identified, leading to a diagnosis of idiopathic uveitis. - This highlights the multifactorial nature of the condition, where various triggers or underlying predispositions may not always be evident. *CMV* - **Cytomegalovirus (CMV)** typically causes a **posterior uveitis** or **retinitis**, especially in immunocompromised individuals. - While CMV can rarely cause anterior uveitis, it is not the most common cause. *Toxoplasma* - **Toxoplasmosis** is a frequent cause of **posterior uveitis** or **chorioretinitis**, characterized by focal necrotic lesions in the retina. - It is not a common cause of isolated anterior uveitis, although anterior chamber inflammation can occur secondary to posterior disease. *Ankylosing spondylitis* - **Ankylosing spondylitis** is a well-known systemic condition associated with **acute anterior uveitis**. - However, while a significant association exists, it is not the single most common cause when considering all cases of anterior uveitis, many of which remain idiopathic.

Q: Corneal endothelial cell count is measured by?

Specular microscope. ***Specular microscope*** - A **specular microscope** is specifically designed to provide a high-magnification, non-contact view of the **corneal endothelium**, allowing for direct visualization and counting of endothelial cells. - It measures cell density, morphology, and polymegethism, which are crucial for assessing corneal health, especially before and after intraocular surgeries. *Ophthalmoscope* - An **ophthalmoscope** is used to examine the **fundus** or the back of the eye, including the retina, optic disc, macula, and blood vessels. - It does not have the magnification capabilities required to visualize or count individual corneal endothelial cells. *Synoptophore* - A **synoptophore** is an instrument used to diagnose and treat **strabismus** (eye misalignment) and to assess **binocular vision**. - Its function involves showing different images to each eye to test fusion, suppression, and stereopsis, unrelated to corneal cell count. *Amsler's grid* - **Amsler's grid** is a diagnostic tool used to detect **macular degeneration** and other retinal diseases that affect central vision. - It consists of a grid of straight lines and helps identify distortion or missing areas in the patient's central visual field.

Q: The reduced effect of low astigmatism in dim light is primarily due to:

Pupil constriction. ***Pupil constriction*** - In dim light conditions, patients with low astigmatism may experience **reduced symptoms** due to the **pinhole effect** of pupil constriction when they squint or strain to see better. - **Pupil constriction** limits light entry to the central optical zone, reducing the effect of irregular corneal curvature by creating a smaller aperture that acts like a **stenopic slit**. - This **pinhole effect** improves depth of focus and reduces blur from astigmatism by eliminating peripheral aberrant rays. - When viewing in dim light, patients naturally squint to improve clarity, which mimics pupil constriction and reduces astigmatic blur. *Pupil dilatation* - **Pupil dilatation** in dim light would actually *increase* astigmatic symptoms, not reduce them. - A larger pupil allows more peripheral rays to enter the eye, which pass through areas of the lens and cornea with greater refractive error. - This increases the blur circle and worsens the optical quality in uncorrected astigmatism. *Increased curvature of lens* - **Increased lens curvature** (accommodation) increases refractive power but does not correct the unequal curvature of different meridians that defines astigmatism. - This would not specifically reduce astigmatic blur in dim light conditions. *Decreased curvature of lens* - **Decreased lens curvature** reduces refractive power and is associated with relaxed accommodation. - This does not address the fundamental issue of unequal meridional refraction in astigmatism.

Q: Which type of cataract is specifically associated with decreased reading ability?

Nuclear cataract. ***Nuclear cataract*** - **Nuclear cataracts** cause progressive hardening and yellowing of the lens nucleus with increased refractive index - This produces a **myopic shift** that initially causes **"second sight"** (temporary improvement in near vision) - However, as the cataract progresses, the increasing opacity leads to **overall visual decline affecting both distance and near vision**, including reading ability - Among the given options, nuclear cataract is the most common age-related cataract that significantly impairs vision including reading *Blue dot cataract* - **Blue dot cataracts** (cerulean cataracts) are small, bluish peripheral opacities, usually congenital and stationary - They rarely cause significant visual impairment and do not affect reading ability *Fusiform cataract* - **Fusiform cataracts** are congenital spindle-shaped opacities along the visual axis - While they can affect vision if dense, they are rare and not typically associated with progressive reading difficulty *Punctate cataract* - **Punctate cataracts** are small, scattered dot-like opacities in the lens - They are often congenital or age-related and cause minimal visual disturbance - Not specifically associated with decreased reading ability

Q: What is the primary mechanism of pathogenesis in acute angle closure glaucoma?

Outflow obstruction due to anatomical factors. ***Outflow obstruction due to anatomical factors*** - **Acute angle-closure glaucoma (AACG)** occurs due to a sudden blockage of the **trabecular meshwork**, which is the primary drainage pathway for aqueous humor. - This blockage is caused by anatomical predispositions, such as a **narrow anterior chamber angle**, relatively large lens, and **pupillary block** leading to iris bombé with peripheral iris bowing forward. - The iridocorneal angle closure prevents aqueous humor drainage, causing **rapid IOP elevation**. *Increased secretion of aqueous humor* - While increased aqueous humor production can contribute to elevated intraocular pressure, it is **not the primary mechanism** in acute angle-closure glaucoma. - This mechanism is more relevant in **open-angle glaucoma** or conditions with ciliary body overactivity. - AACG's hallmark is **outflow obstruction**, not increased production. *Decreased ciliary body function* - Decreased ciliary body function would **reduce aqueous humor production**, leading to **hypotony** (low IOP), not elevated pressure. - This is the opposite of what occurs in AACG, where IOP rises dramatically due to impaired drainage. - Ciliary body dysfunction is seen in conditions like **uveitis** or post-surgical complications. *Increased absorption of aqueous humor* - **Increased absorption** of aqueous humor would **reduce intraocular pressure**, which is the opposite of what occurs in acute angle-closure glaucoma. - The disease is characterized by a **rapid and severe rise in intraocular pressure** due to impaired outflow, not enhanced absorption. - Normal aqueous absorption occurs via trabecular and uveoscleral pathways, both of which are blocked in AACG.

Q: What condition is characterized by cherry red spot at the macula with retinal whitening?

CRAO. ***CRAO*** - **Central retinal artery occlusion (CRAO)** is characterized by **sudden, profound, painless monocular vision loss**. - The classic funduscopic finding is a **cherry-red spot at the macula** with diffuse **retinal whitening** due to ischemia. *CRVO* - **Central retinal vein occlusion (CRVO)** presents with **painless vision loss** but typically shows **hemorrhages**, **dilated tortuous veins**, and **cotton wool spots** on funduscopic exam. - It does not usually cause retinal whitening or a cherry-red spot. *Diabetic retinopathy* - **Diabetic retinopathy** is characterized by **microaneurysms**, **hemorrhages**, **hard exudates**, and **cotton wool spots**, and can lead to neovascularization. - It does not present with acute retinal whitening or a cherry-red spot in the macula. *Syphilitic retinopathy* - **Syphilitic retinopathy** can cause a variety of presentations, including **retinal vasculitis**, **chorioretinitis**, and **optic neuritis**. - It does not typically manifest as a cherry-red spot with diffuse retinal whitening at the macula.

Q: Most common cause of bilateral optic atrophy is:

Nutritional deficiency (B12/folate). ***Nutritional deficiency (B12/folate)*** - **Nutritional optic neuropathy** due to deficiencies in B vitamins (especially B12, thiamine) and folate is a common cause of bilateral optic atrophy, particularly in **developing countries** and in populations with **malnutrition or chronic alcoholism**. - These deficiencies impair the **metabolism of retinal ganglion cells** and their axons, leading to symmetric bilateral optic nerve degeneration. - The condition is often **reversible in early stages** with appropriate supplementation. - **Note:** The "most common" cause varies by geographic location, population, and clinical setting. *Hereditary optic neuropathy* - **Leber's hereditary optic neuropathy (LHON)** and **autosomal dominant optic atrophy (ADOA)** are major causes of bilateral optic atrophy, especially in **younger patients**. - LHON typically presents in young males (15-35 years) with **sequential bilateral visual loss**. - These are among the **most common inherited optic neuropathies** and should always be considered in bilateral cases. *Intracranial tumor* - Intracranial tumors typically cause **unilateral optic atrophy** due to direct compression of one optic nerve. - **Bilateral optic atrophy** can occur with **chiasmal or suprasellar tumors** (pituitary adenomas, craniopharyngiomas) but is less common. - Usually presents with **visual field defects** (bitemporal hemianopia) before significant atrophy develops. *Toxic optic neuropathy* - **Toxic optic neuropathies** result from exposure to substances such as **methanol, ethambutol, tobacco-alcohol amblyopia**, or isoniazid. - Can cause bilateral symmetric optic atrophy but are **exposure-dependent** and less prevalent in general population. - **Tobacco-alcohol amblyopia** may overlap with nutritional deficiency.

Question 1

Child with mild squint. Intrauterine, birth history, developmental history till date all normal. Corneal light reflex normal. All other eye parameters normal except exaggerated epicanthal fold. Diagnosis ?

Accepted Answer

Pseudostrabismus

Answer

Exophoria (outward drift)

Answer

Esophoria (inward drift)

Answer

Accommodative esotropia

Question 2

What is the most common orbital tumor in children?

Accepted Answer

Hemangioma

Answer

Nerve sheath tumor

Answer

Lymphoma

Answer

Meningioma

Question 3

What is the term for an abnormally eccentrically placed pupil?

Accepted Answer

Corectopia

Answer

Polycoria

Answer

Ectopia lentis

Answer

Anisocoria

Question 4

What is the most common cause of anterior uveitis?

Accepted Answer

Idiopathic

Answer

CMV

Answer

Toxoplasma

Answer

Ankylosing spondylitis

Question 5

Corneal endothelial cell count is measured by?

Accepted Answer

Specular microscope

Answer

Ophthalmoscope

Answer

Synoptophore

Answer

Amsler's grid

Question 6

The reduced effect of low astigmatism in dim light is primarily due to:

Accepted Answer

Pupil constriction

Answer

Pupil dilatation

Answer

Increased curvature of lens

Answer

Decreased curvature of lens

Question 7

Which type of cataract is specifically associated with decreased reading ability?

Accepted Answer

Nuclear cataract

Answer

Blue dot cataract

Answer

Fusiform cataract

Answer

Punctate cataract

Question 8

What is the primary mechanism of pathogenesis in acute angle closure glaucoma?

Accepted Answer

Outflow obstruction due to anatomical factors

Answer

Increased secretion of aqueous humor

Answer

Increased absorption of aqueous humor

Answer

Decreased ciliary body function

Question 9

What condition is characterized by cherry red spot at the macula with retinal whitening?

Accepted Answer

CRAO

Answer

CRVO

Answer

Diabetic retinopathy

Answer

Syphilitic retinopathy

Question 10

Most common cause of bilateral optic atrophy is:

Accepted Answer

Nutritional deficiency (B12/folate)

Answer

Intracranial tumor

Answer

Hereditary optic neuropathy

Answer

Toxic optic neuropathy

NEET-PG 2012 — Ophthalmology