NEET-PG 2015 - Ophthalmology Practice Questions

Q: D Shaped pupil is seen in which condition?

Iridodialysis. ***Iridodialysis*** - **Iridodialysis** is a disinsertion or separation of the iris from its root at the ciliary body. - This separation creates a D-shaped or keyhole pupil, as the detached portion of the iris no longer contributes to the circular pupillary margin. *Anterior Uveitis* - **Anterior uveitis** is inflammation of the iris and ciliary body, primarily causing miosis (constricted pupil), not a D-shaped pupil. - It can lead to posterior synechiae, resulting in an irregular, but not typically D-shaped, pupil. *Anterior synechiae* - **Anterior synechiae** involve adhesions between the iris and the corneal endothelium or trabecular meshwork. - While they can cause an irregular pupil shape, they typically pull the iris towards the cornea rather than creating a D-shape from iris root disinsertion. *Iridodonesis* - **Iridodonesis** refers to tremors or wobbling of the iris, often seen in cases of aphakia or subluxated lenses, due to lack of support. - It describes a movement disorder of the iris rather than an abnormal, fixed pupil shape like a D-shaped pupil.

Q: In a case of myopia, LASIK can correct up to how many diopters?

-12D. ***-12D*** - LASIK can effectively correct myopia up to approximately **-12 diopters** in suitable candidates, though this can vary slightly based on individual corneal thickness and health. - The excimer laser reshapes the **cornea** to reduce its curvature, thereby decreasing the focusing power of the eye and correcting the myopic error. *-20D* - While some highly myopic individuals might desire such a correction, LASIK is generally not recommended or effective for myopia higher than **-12 to -14 diopters** due to limitations in corneal tissue removal and potential for complications. - Correcting very high myopia with LASIK would require removing too much corneal tissue, potentially leading to **corneal instability** or vision-threatening complications like **ectasia**. *-6D* - This is a common and highly successful range for LASIK correction, but it represents only a **moderate level of myopia** and not the maximum correctable range. - Patients with myopia of -6D typically achieve excellent visual outcomes with very low complication rates after LASIK. *-4D* - This is a relatively low level of myopia, and LASIK is very effective for this amount of correction, but it is far from the **upper limit** of what LASIK can achieve. - This level of correction requires minimal corneal reshaping and typically results in a very high success rate and predictable outcomes.

Q: What is the primary predisposing factor for retinopathy of prematurity?

Low gestational age. ***Low gestational age*** - **Prematurity** is the most significant risk factor, as the **retinal vasculature** is still immature and susceptible to abnormal development. - The earlier the gestational age, the **higher the risk** of ROP developing and progressing to severe stages. *Low birth weight* - While strongly correlated with ROP, **low birth weight** is often a consequence of prematurity rather than the primary predisposing factor itself. - Many term infants can have low birth weight due to **intrauterine growth restriction** but do not typically develop ROP. *Oxygen toxicity* - **Supplemental oxygen** can exacerbate ROP by causing initial **vasoconstriction** and subsequent abnormal vessel proliferation. - However, it acts as a secondary trigger in an already vulnerable, premature retina, not the primary predisposing factor. *Carbohydrate excess* - **Carbohydrate excess** is not a recognized predisposing factor for retinopathy of prematurity. - This condition is primarily related to the **vascular development of the retina** in premature infants.

Q: Which of the following is not a standard treatment for myopia?

Holmium laser thermoplasty. ***Holmium laser thermoplasty*** - This procedure was explored for the treatment of **hyperopia**, not myopia, as it aims to steepen the cornea to increase its refractive power. - It involves using a holmium laser to apply heat to the peripheral cornea, causing **collagen shrinkage** and steepening, which is the opposite of what is needed for myopia correction. *LASIK* - **LASIK (Laser-Assisted in Situ Keratomileusis)** is a common and effective surgical procedure for correcting myopia by reshaping the cornea to reduce its refractive power. - It involves creating a **corneal flap** and using an excimer laser to remove tissue from the underlying stromal bed. *Phakic intraocular lens* - **Phakic intraocular lenses (IOLs)** are implanted into the eye without removing the natural lens and are a standard treatment for moderate to high myopia, especially in patients not suitable for LASIK. - They work by adding refractive power to the eye, allowing light to focus correctly on the retina. *Radial Keratotomy* - **Radial Keratotomy (RK)** was an early surgical procedure for myopia, involving making radial incisions in the cornea to flatten it and reduce its refractive power. - Although largely replaced by LASIK due to its unpredictable outcomes and potential for glare and night vision problems, it was historically a standard treatment for myopia.

Q: In which of the following conditions does Berlin's edema occur?

After concussional trauma. ***After concussional trauma*** - **Berlin's edema**, also known as **commotio retinae**, is a form of **retinal edema** that occurs following **blunt trauma** to the eye. - It results from the disruption of the **photoreceptor outer segments** and retinal pigment epithelium, leading to a **dull, gray-white appearance** of the retina. *Open angle glaucoma* - Characterized by **progressive optic nerve damage** and visual field loss, typically due to elevated intraocular pressure, without retinal edema. - The primary pathology involves the **trabecular meshwork**, not direct retinal swelling. *After cataract surgery* - A common complication is **cystoid macular edema** (Irvine-Gass syndrome), which affects the macula and can cause blurred vision. - This is distinct from Berlin's edema, as it is a **post-surgical inflammatory response**, not a direct traumatic injury. *Diabetic retinopathy* - Involves various retinal changes due to diabetes, such as **microaneurysms**, hemorrhages, and **macular edema** from leaky vessels. - It is a **metabolic and vascular disease**, not a direct consequence of acute ocular trauma.

Q: Descemet membrane breach is seen in ?

Congenital glaucoma (Buphthalmos). ***Congenital glaucoma (Buphthalmos)*** - In **congenital glaucoma**, increased intraocular pressure (IOP) in infancy stretches the developing eye, leading to enlargement (buphthalmos) and **Descemet membrane breaches** or ruptures. - These ruptures appear as fine, parallel, or branching lines on the posterior corneal surface, known as **Haab's striae**, which are characteristic signs of this condition. *Angle closure glaucoma* - This condition involves a sudden rise in IOP due to physical obstruction of the **aqueous humor outflow** and does not typically cause Descemet membrane breaks. - Clinical signs include **corneal edema** due to endothelial dysfunction, but not membrane breaches. *Acute Iridocyclitis* - **Acute iridocyclitis** is an inflammatory condition of the iris and ciliary body, primarily causing cells and flare in the anterior chamber. - It does not directly lead to **Descemet membrane breaches** or structural damage like stretching of the cornea. *Subconjunctival hemorrhage* - This condition is characterized by **bleeding under the conjunctiva** and is typically due to ruptured conjunctival blood vessels. - It is a superficial condition that does not involve the cornea or the Descemet membrane.

Q: What is the typical appearance of a subhyaloid hemorrhage in the eye?

Boat shaped. ***Boat shaped*** - A subhyaloid hemorrhage is located beneath the **hyaloid membrane** (the posterior vitreous cortex), which is attached to the retina. - The collected blood often assumes a **dependent, gravity-influenced shape**, appearing flat on top and curved underneath, resembling a boat. *Crescent shaped* - This shape is not characteristic of a typical subhyaloid hemorrhage; it might be seen in other types of hemorrhages or detachment patterns. - **Crescentic shapes** are more commonly associated with certain types of **retinal detachments** or tears where fluid accumulation takes on a curved boundary. *Round* - While hemorrhages can be round, a subhyaloid hemorrhage typically spreads out due to gravity within the confined space, resulting in a more distinct shape. - A **perfectly round hemorrhage** is less common in the subhyaloid space as blood tends to layer out rather than remain as a sphere. *Flame shaped* - **Flame-shaped hemorrhages** are typically found in the **nerve fiber layer** due to the orientation of nerve fibers. - These hemorrhages are shallower and follow the linear arrangement of nerve fibers, unlike the larger, more globular subhyaloid bleeds.

Q: Which organism can penetrate corneal endothelium?

Haemophilus influenzae. ***Haemophilus influenzae*** - *Haemophilus influenzae* is unique in its ability to penetrate the **intact corneal endothelium** through its specific virulence factors and enzymatic mechanisms. - Along with *Neisseria meningitidis*, it can breach the **Descemet's membrane and endothelial barrier** without requiring prior epithelial damage. - This property makes it particularly dangerous as it can cause **endophthalmitis** by directly accessing the anterior chamber. *Neisseria gonorrhoeae* - While highly virulent, *N. gonorrhoeae* penetrates the **corneal epithelium** (outer layer) through its proteases, not the endothelium (inner layer). - It causes severe **hyperacute conjunctivitis** and can lead to **corneal perforation**, but via epithelial destruction and stromal infiltration. *Staphylococcus aureus* - A common cause of **bacterial keratitis** following epithelial defects or trauma. - Causes stromal infiltration and abscess formation but **cannot penetrate intact endothelium**. *Aspergillus fumigatus* - This fungus causes **fungal keratitis** typically after trauma with vegetative matter. - Invades through **epithelial breaches** and stromal infiltration, not through intact endothelial penetration.

Question 1

D Shaped pupil is seen in which condition?

Accepted Answer

Iridodialysis

Answer

Anterior synechiae

Answer

Anterior Uveitis

Answer

Iridodonesis

Question 2

In a case of myopia, LASIK can correct up to how many diopters?

Accepted Answer

-12D

Answer

-4D

Answer

-20D

Answer

-6D

Question 3

What is the primary predisposing factor for retinopathy of prematurity?

Accepted Answer

Low gestational age

Answer

Oxygen toxicity

Answer

Carbohydrate excess

Answer

Low birth weight

Question 4

Which of the following is not a standard treatment for myopia?

Accepted Answer

Holmium laser thermoplasty

Answer

Phakic intraocular lens

Answer

Radial Keratotomy

Answer

LASIK

Question 5

Rigid gas permeable (RGP) lenses are made from which of the following combinations of materials?

Accepted Answer

Copolymer of PMMA, Silicon containing monomer & cellulose acetyl butyrate

Answer

Hydroxymethylmethacrylate

Answer

Cellulose acetate Butyrate

Answer

Polymethylmethacrylate

Question 6

In which of the following conditions does Berlin's edema occur?

Accepted Answer

After concussional trauma

Answer

Open angle glaucoma

Answer

After cataract surgery

Answer

Diabetic retinopathy

Question 7

Descemet membrane breach is seen in ?

Accepted Answer

Congenital glaucoma (Buphthalmos)

Answer

Angle closure glaucoma

Answer

Acute Iridocyclitis

Answer

Subconjunctival hemorrhage

Question 8

What is the typical appearance of a subhyaloid hemorrhage in the eye?

Accepted Answer

Boat shaped

Answer

Crescent shaped

Answer

Round

Answer

Flame shaped

Question 9

Which organism can penetrate corneal endothelium?

Accepted Answer

Haemophilus influenzae

Answer

Staphylococcus Aureus

Answer

Aspergillus fumigatus

Answer

Neisseria gonorrhoeae

Question 10

Aniseikonia is ?

Accepted Answer

Projection of different sized images into visual cortex of two retinae

Answer

Projection of different colored images into the visual cortex of one eye

Answer

Change in the perception of object size due to distance

Answer

Temporary visual disturbances affecting one eye

NEET-PG 2015 — Ophthalmology