NEET-PG 2012 - Ophthalmology Practice Questions

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 is the most common cause of vitreous hemorrhage in diabetic retinopathy?

Proliferative diabetic retinopathy. ***Proliferative diabetic retinopathy*** - **Neovascularization** is the hallmark of proliferative diabetic retinopathy (PDR), where new, fragile blood vessels grow on the surface of the retina and optic disc. - These delicate vessels can easily rupture and bleed into the vitreous humor, leading to a **vitreous hemorrhage**. *Non-proliferative diabetic retinopathy* - This stage is characterized by **microaneurysms**, hemorrhages, and cotton wool spots, but typically lacks significant neovascularization. - While it involves retinal vascular damage, the absence of **newly formed, fragile vessels** makes vitreous hemorrhage less common. *Severe non-proliferative diabetic retinopathy* - This stage shows extensive microvascular abnormalities, including numerous hemorrhages and venular beading, but generally **still no new vessel formation**. - Without the presence of **fragile neovascular membranes**, the risk of significant vitreous hemorrhage is lower compared to PDR. *Diabetic macular edema* - This condition involves **fluid leakage** from damaged retinal vessels into the macula, causing vision loss. - While it's a common complication of diabetes, it primarily causes **macular swelling** and does not directly lead to vitreous hemorrhage.

Q: What is the definition of the visual axis in relation to the eye?

Line from the object to the fovea. ***Line from the object to the fovea*** - The **visual axis** is the theoretical line connecting the **object of regard** in the external world to the **fovea centralis** (the area of sharpest vision) on the retina. - This axis passes through the **nodal points** of the eye, which are conceptual points within the lens system acting as optical centers. *Line from the center of the lens to the cornea* - This description does not correspond to any standard anatomical or optical axis of the eye. - The **cornea** and **lens** are parts of the eye's refracting system, but a line solely between their centers would not define visual perception. *Line from the center of the cornea to the center of the lens* - This line is generally referred to as the **optical axis**, which is an anatomical reference line. - The optical axis typically passes through the centers of curvature of the refractive surfaces, but it does not necessarily align with the actual line of sight or the path of light from an object to the fovea. *None of the options* - This option is incorrect because the first option accurately defines the visual axis.

Q: Which of the following is NOT typically seen in 3rd nerve palsy?

Loss of abduction. ***Loss of abduction*** - The **oculomotor nerve (CN III)** controls adduction, elevation, and depression of the eye, but **not abduction**. [2] - **Abduction** is primarily controlled by the **abducens nerve (CN VI)**, so its loss would indicate a CN VI palsy. *Mydriasis* - The **oculomotor nerve (CN III)** innervates the **parasympathetic fibers** to the pupillary constrictor muscles. [3] - Palsy of these fibers leads to unopposed action of the sympathetic dilator muscles, causing **mydriasis (pupil dilation)**. [4] *Ptosis* - The **oculomotor nerve (CN III)** innervates the **levator palpebrae superioris muscle**, which lifts the eyelid. - Dysfunction of this nerve leads to **ptosis (drooping of the eyelid)**. [1] *Loss of light reflex* - The **efferent pathway** for the **pupillary light reflex** travels via the **oculomotor nerve (CN III)** to constrict the pupil. [3] - A 3rd nerve palsy, particularly affecting the parasympathetic fibers, **impairs pupillary constriction**, resulting in a loss of the direct and consensual light reflex in the affected eye. [4]

Q: What is the primary complication associated with Eale's disease?

Vitreous hemorrhage. ***Vitreous hemorrhage*** - **Vitreous hemorrhage** is a common and often visually debilitating complication of Eale's disease, resulting from the rupture of fragile new vessels. - The proliferative stage of Eale's disease involves the development of **neovascularization** on the retina, which can bleed into the vitreous humor. *Retinal hemorrhage* - While **retinal hemorrhages** can occur in Eale's disease, they are often precursors to or components of vitreous hemorrhage, not the primary, most significant complication. - Retinal hemorrhages alone may cause less severe vision loss compared to the extensive obscuration by vitreous bleeding. *Conjunctival hemorrhage* - **Conjunctival hemorrhage** involves bleeding in the superficial layers of the eye and is not typically associated with the underlying vasculitis of Eale's disease. - This is a benign condition and not a primary complication of a retinal vascular disorder. *Choroidal hemorrhage* - **Choroidal hemorrhage** occurs beneath the retina and is usually associated with trauma, surgery, or degenerative conditions like age-related macular degeneration, not Eale's disease. - Eale's disease primarily affects the **retinal vasculature**, leading to bleeding internally into the vitreous.

Q: Irregular pupil is seen in which of the following conditions?

Trauma. ***Trauma*** - **Direct injury to the iris** can cause tears or distortion, leading to an **irregularly shaped pupil** - Results in conditions like **traumatic mydriasis** (dilated pupil) or **iridodialysis** (iris detachment from its root at the ciliary body) - **Sphincter pupillae tears** cause characteristic irregularity with notching or peaked appearance *Glaucoma* - Primarily characterized by **optic nerve damage** due to increased intraocular pressure - In acute angle closure glaucoma, pupil may be **mid-dilated and fixed**, but remains **round**, not irregular - Pupil shape irregularity is not a feature of chronic glaucoma *Retinal detachment* - Involves **separation of the neurosensory retina** from the underlying retinal pigment epithelium - This is a **posterior segment pathology** that does not affect anterior segment structures - **Pupil shape remains regular** despite severe vision loss *Oculomotor palsy* - Affects the **third cranial nerve (CN III)**, leading to ptosis, strabismus, and loss of parasympathetic innervation - Pupil is typically **dilated and fixed** due to unopposed sympathetic action - Pupil remains **round but unresponsive to light**, not irregular in shape

Q: Which muscle is the earliest to be involved in thyroid ophthalmopathy?

Inferior Rectus (IR). ***Inferior Rectus (IR)*** - The **inferior rectus muscle** is most commonly and earliest affected in **thyroid ophthalmopathy** due to its anatomical location and muscle fiber type, making it highly susceptible to inflammation and edema. - Involvement of the inferior rectus leads to restricted **upward gaze** and **diplopia**, which are characteristic early symptoms of thyroid eye disease. *Medial Rectus (MR)* - While the **medial rectus** is often involved in thyroid ophthalmopathy, it is typically affected *after* the inferior rectus. - Dysfunction of the medial rectus manifests as difficulty with **adduction** (moving the eye inwards). *Superior Rectus (SR)* - The **superior rectus** is less frequently and usually later involved compared to the inferior and medial rectus muscles. - Its involvement typically causes restricted **downward gaze**. *Lateral Rectus (LR)* - The **lateral rectus** muscle is the *least common* ocular muscle to be affected in thyroid ophthalmopathy. - When affected, it primarily causes difficulty with **abduction** (moving the eye outwards).

Q: Which type of congenital cataract is commonly associated with significant visual defects?

Nuclear cataract. ***Nuclear cataract*** - It involves the **nucleus** of the lens, which is the central and most visually critical part. - This type of cataract can cause **significant visual impairment** due to its central location and density, impacting early visual development. *Punctate Cataract* - These are **small, dot-like opacities** that are usually clinically insignificant and do not typically cause significant visual defects. - They are often **peripheral** or very fine, thus not obstructing the central visual axis. *Blue dot cataract* - Also known as **cerulean cataract**, this type consists of small, bluish opacities in the lens cortex. - While congenital, it often has **minimal impact on vision** and is frequently observed incidentally. *Fusiform cataract* - This cataract forms in the shape of a **spindle or needle**, usually along the visual axis. - While it can sometimes cause minor visual compromise, its impact is generally **less severe** compared to a dense nuclear cataract.

Q: What does extraretinal fibrovascular proliferation at the ridge indicate?

Stage III Retinopathy of Prematurity. ***Stage III Retinopathy of Prematurity*** - Extraretinal fibrovascular proliferation at the ridge is the defining characteristic of **Stage III Retinopathy of Prematurity (ROP)**. - This stage signifies significant **neovascularization** extending into the vitreous, increasing the risk of **retinal detachment**. *Normal retina* - A normal retina does not exhibit **fibrovascular proliferation** or a distinct ridge, as its vascularization is fully developed and confined to the retinal plane. - Absence of any abnormal vascular growth or demarcation line indicates a healthy, mature retinal structure. *Stage II Retinopathy of Prematurity* - Stage II ROP is characterized by a **ridge** that is elevated and appears three-dimensional, but it **lacks extraretinal fibrovascular proliferation**. - This stage represents progression from Stage I, where the demarcation line becomes a prominent ridge, but without new vessel formation outside the retina. *Stage I Retinopathy of Prematurity* - Stage I ROP is characterized by a thin, flat **demarcation line** distinguishing vascularized from avascular retina, without any significant elevation or fibrovascular proliferation. - This initial stage indicates an arrested phase of retinal vascular development, but without the more severe signs of neovascularization.

Q: In which condition is the swinging light test positive?

Optic neuritis. ***Optic neuritis*** - The swinging light test (also known as the **Marcus Gunn pupil** or relative afferent pupillary defect, RAPD) is positive when there is a significant **asymmetry in the afferent visual pathway** between the two eyes. - In optic neuritis, the **optic nerve** is inflamed and demyelinated, impairing the transmission of light signals to the brain, which leads to a paradoxical pupillary dilation when the light is swung from the unaffected to the affected eye. *Conjunctivitis* - This is an **inflammation of the conjunctiva**, the membrane lining the eyelid and sclera, which primarily affects the ocular surface. - It does not involve the optic nerve or afferent pupillary pathways, so the swinging light test would be **negative**. *Glaucoma* - Glaucoma is a condition characterized by **progressive optic nerve damage**, often associated with elevated intraocular pressure, leading to peripheral vision loss. - While it causes optic neuropathy, a positive swinging light test is typically seen only in **severe, asymmetric cases** and is not its primary diagnostic feature. *Keratoconus* - This is a non-inflammatory eye condition in which the normally round dome-shaped cornea **thins and bulges outward into a cone-like shape**. - It affects the **cornea's shape and vision quality**, but not the optic nerve or the afferent pupillary reflex pathway, thus the swinging light test would be negative.

Question 1

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 2

What is the most common cause of vitreous hemorrhage in diabetic retinopathy?

Accepted Answer

Proliferative diabetic retinopathy

Answer

Non-proliferative diabetic retinopathy

Answer

Severe non-proliferative diabetic retinopathy

Answer

Diabetic macular edema

Question 3

What is the definition of the visual axis in relation to the eye?

Accepted Answer

Line from the object to the fovea

Answer

Line from the center of the lens to the cornea

Answer

Line from the center of the cornea to the center of the lens

Answer

None of the options

Question 4

Which of the following is NOT typically seen in 3rd nerve palsy?

Accepted Answer

Loss of abduction

Answer

Mydriasis

Answer

Ptosis

Answer

Loss of light reflex

Question 5

What is the primary complication associated with Eale's disease?

Accepted Answer

Vitreous hemorrhage

Answer

Retinal hemorrhage

Answer

Conjunctival hemorrhage

Answer

Choroidal hemorrhage

Question 6

Irregular pupil is seen in which of the following conditions?

Accepted Answer

Trauma

Answer

Glaucoma

Answer

Retinal detachment

Answer

Oculomotor palsy

Question 7

Which muscle is the earliest to be involved in thyroid ophthalmopathy?

Accepted Answer

Inferior Rectus (IR)

Answer

Medial Rectus (MR)

Answer

Superior Rectus (SR)

Answer

Lateral Rectus (LR)

Question 8

Which type of congenital cataract is commonly associated with significant visual defects?

Accepted Answer

Nuclear cataract

Answer

Punctate Cataract

Answer

Blue dot cataract

Answer

Fusiform cataract

Question 9

What does extraretinal fibrovascular proliferation at the ridge indicate?

Accepted Answer

Stage III Retinopathy of Prematurity

Answer

Normal retina

Answer

Stage II Retinopathy of Prematurity

Answer

Stage I Retinopathy of Prematurity

Question 10

In which condition is the swinging light test positive?

Accepted Answer

Optic neuritis

Answer

Conjunctivitis

Answer

Glaucoma

Answer

Keratoconus

NEET-PG 2012 — Ophthalmology