NEET-PG 2015 - Ophthalmology Practice Questions

Q: Silk retina is seen in ?

Retinal detachment. ***Retinal detachment*** - **"Silk retina" or "silky sheen"** is a classic ophthalmoscopic finding in retinal detachment, describing the **smooth, glistening appearance** of the detached sensory retina. - The detached retina appears **elevated, gray, and translucent** with characteristic folds or undulations, exhibiting a **satiny or silky luster** when examined. - Patients typically present with **photopsias (flashes of light)**, **floaters**, and progressive **visual field defect** described as a "curtain" or "shadow." - This is a true **ophthalmic emergency** requiring urgent surgical intervention. *Diabetic retinopathy* - Characterized by **microaneurysms, dot-blot hemorrhages, hard exudates**, and **cotton-wool spots** in non-proliferative stages. - Proliferative diabetic retinopathy shows **neovascularization** and vitreous hemorrhage. - Does not produce the "silk retina" appearance. *Macular degeneration* - Age-related macular degeneration presents with **drusen, pigmentary changes**, and in advanced stages, **geographic atrophy** or **choroidal neovascularization**. - May show a **"beaten-bronze" appearance** in certain macular dystrophies (Best's disease), but not "silk retina." - Central vision loss is the predominant symptom. *Hypertensive retinopathy* - Features include **generalized arteriolar narrowing, AV nicking, flame-shaped hemorrhages**, and **cotton-wool spots**. - In severe cases (Grade IV), **optic disc edema** and macular star exudates may occur. - Vascular changes dominate the clinical picture, not a silky retinal appearance.

Q: Pseudopapilledema with tigroid fundus appearance is seen in?

Myopia. ***Myopia*** - **Pseudopapilledema** with a **tigroid fundus** (tessellated or salt-and-pepper appearance) is characteristically observed in high myopia due to the oblique entry of the **optic nerve** into the globe and thinning of the choroid and retinal pigment epithelium. - The pseudopapilledema is caused by the crowding of axons and glial tissue within the optic disc, giving a raised appearance, and is distinct from true papilledema which involves **optic disc edema** due to increased **intracranial pressure**. - The tigroid fundus results from the visibility of underlying **choroidal vessels** through the attenuated retinal pigment epithelium in the stretched, elongated myopic eye. *Hypermetropia* - **Hypermetropia** (farsightedness) typically presents with a small, compact optic disc, but does not exhibit the specific findings of **pseudopapilledema** or tigroid fundus. - This condition is characterized by the eye being too short or the lens having insufficient power, causing light to focus behind the retina. *Astigmatism* - **Astigmatism** is characterized by an **irregularly shaped cornea** or lens, leading to blurred vision at all distances. - While it can cause some distortion, it is not associated with the specific optic disc appearance of **pseudopapilledema** or the fundus changes seen in high myopia. *Presbyopia* - **Presbyopia** is an age-related condition where the eye's natural lens loses its flexibility, making it difficult to focus on **near objects**. - It affects the **accommodative ability** of the eye and does not manifest with any characteristic changes in the optic disc morphology such as **pseudopapilledema** or retinal/choroidal changes.

Q: 1mm change in axial length of the eyeball would change the refracting power of the eye by?

3D. ***3D*** - A 1mm change in the **axial length** of the eyeball leads to an approximate **3 diopter (D) change** in the refractive power of the eye. - This relationship is crucial for understanding **refractive errors** like myopia (if the eyeball is too long) or hyperopia (if it's too short). *1D* - A 1D change in refractive power corresponds to a much larger change in the **focal length** of the eye, not typically 1mm in axial length. - This value is too small to reflect the significant impact of a 1mm axial length alteration on the eye's focusing ability. *2D* - While a direct relationship exists, 2D is an **underestimation** of the actual refractive change caused by a 1mm alteration in axial length. - This value would imply a less sensitive optical system than the human eye. *4D* - A 4D change would represent an **overestimation** of the refractive power change for a 1mm alteration in axial length. - Such a high value is generally seen with more substantial anatomical variations or surgical interventions.

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: What does a lensometer measure?

The refractive power of corrective lenses. ***The refractive power of corrective lenses*** - A **lensometer**, also known as a focimeter or vertometer, is an ophthalmological instrument used to measure the **refractive power** of spectacle lenses, contact lenses, and intraocular lenses. - It determines parameters such as **sphere**, **cylinder**, and **axis**, providing essential information for dispensing and fabricating corrective eyewear. *Corneal topography* - **Corneal topography** maps the curvature and shape of the cornea and is performed by a **topographer**. - This instrument is primarily used to diagnose and monitor conditions like **keratoconus** and to plan refractive surgeries. *Biochemical constitution of lens* - The **biochemical constitution** of the lens refers to its molecular makeup, including proteins and metabolites. - This is typically assessed through laboratory techniques like **spectroscopy** or **chromatography**, not a lensometer. *Power of IOL* - While a lensometer can measure the power of an **intraocular lens (IOL)** once it is manufactured, the initial power calculation for an IOL before implantation is determined using **biometry** (e.g., A-scan ultrasound or optical biometry). - **Biometry** measures the axial length of the eye and corneal curvature to calculate the appropriate IOL power.

Q: Sudden loss of vision without pain - Which of the following is NOT a cause?

Acute congestive glaucoma. ***Acute congestive glaucoma*** - This condition is characterized by **sudden, severe eye pain** along with blurred vision, redness, and a fixed, mid-dilated pupil. - The pain arises from abrupt elevation of **intraocular pressure**, which differentiates it from painless vision loss. *CRAO* - **Central Retinal Artery Occlusion** (CRAO) typically presents as **sudden, profound, painless monocular vision loss**. - Funduscopic examination often reveals a **cherry-red spot** in the fovea with generalized retinal whitening. *CSR* - **Central Serous Retinopathy** (CSR) causes **sudden, painless blurred vision** or a scotoma, often described as a "watery" or "shimmering" effect. - It involves leakage of fluid under the retina, typically in the macula. *Vitreous Hemorrhage* - Presents as **sudden, painless loss of vision** or a shower of floaters, often described as cobwebs or clouds. - It results from bleeding into the **vitreous cavity**, which can obscure the retina.

Q: All are true regarding cornea except:

The cornea is richly vascular.. ***The cornea is richly vascular.*** - The cornea is an **avascular** tissue, meaning it lacks blood vessels, which is crucial for its transparency. - This avascularity helps prevent light scatter and maintains clear vision. - The cornea receives nutrition from the **aqueous humor**, **tear film**, and **limbal blood vessels** through diffusion. *Endothelium help in maintaining dehydrated state* - The **corneal endothelium** actively pumps fluid out of the corneal stroma via **Na-K-ATPase pumps**, preventing swelling and maintaining its relative state of dehydration. - This **deturgescence** is essential for the cornea's transparency and optimal refractive power. *Oxygen is mostly derived by epithelium directly from the air through tear film* - The corneal **epithelium** primarily obtains oxygen directly from the atmosphere via the **tear film** when the eyes are open. - During sleep, oxygen is primarily supplied by the **palpebral conjunctival vessels**. *Corneal thickness is greater at periphery than center* - The cornea is **thinner at the center** (around 520-540 µm) and gradually **thicker towards the periphery** (around 600-640 µm). - This structural difference contributes to its optical properties and mechanical stability.

Q: What term describes a condition where the axial length of the eye does not match its refractive power?

Axial Ametropia. ***Axial Ametropia*** - This term precisely describes a refractive error where the **axial length** of the eye is either too long or too short relative to its **optical power**, leading to images focusing in front of or behind the retina. - Examples include **myopia** (eye too long) and **hyperopia** (eye too short), which are fundamentally caused by a mismatch in axial length. *Anisokonia* - This condition refers to a significant difference in the **perceived size of images** between the two eyes, often due to unequal refractive errors between the eyes. - It does not directly describe the mismatch between axial length and refractive power itself, but rather a perceptual consequence that can result from asymmetric refractive errors. *Curvature ametropia* - This type of ametropia occurs when the **curvature** of the cornea or lens is abnormal, causing light rays to converge incorrectly. - While it's a form of refractive error, it specifically relates to the curvature of refractive surfaces, not the overall **axial length** of the eyeball. *Emmetropia* - This is the state of having **perfect vision**, where the refractive power of the eye correctly matches its axial length, allowing light to focus precisely on the retina without accommodation. - It describes the absence of refractive error, which is the opposite of the condition described in the question.

Q: Which is the most powerful refractive surface of the eye?

Cornea. ***Cornea*** - The **cornea** is the eye's outermost, transparent layer, responsible for approximately **two-thirds of the total refractive power** of the eye due to its highly curved anterior surface and the significant change in refractive index from air to corneal tissue. - Its fixed curvature and consistent refractive index make it the primary and most powerful component in bending light rays to focus them on the retina. *Conjunctiva* - The **conjunctiva** is a thin, translucent mucous membrane that lines the inner surface of the eyelids and covers the anterior sclera (white part of the eye). - Its primary function is protection and lubrication, producing mucus and tears, but it plays **no significant role in light refraction**. *Vitreous* - The **vitreous humor** is a transparent, gel-like substance that fills the space between the lens and the retina, maintaining the eye's shape. - It has a refractive index very similar to water (approximately 1.334) and contributes **minimally to the eye's total refractive power** because light has already been significantly refracted by the cornea and lens before reaching it. *Lens* - The **lens** is a transparent, biconvex structure located behind the iris, providing the remaining **one-third of the eye's refractive power**. - While crucial for **accommodation** (changing focal length to see objects at different distances), its refractive power is less than the cornea's, and its ability to change shape is what makes it unique, not its absolute power.

Question 1

Silk retina is seen in ?

Accepted Answer

Retinal detachment

Answer

Diabetic retinopathy

Answer

Macular degeneration

Answer

Hypertensive retinopathy

Question 2

Pseudopapilledema with tigroid fundus appearance is seen in?

Accepted Answer

Myopia

Answer

Astigmatism

Answer

Presbyopia

Answer

Hypermetropia

Question 3

1mm change in axial length of the eyeball would change the refracting power of the eye by?

Accepted Answer

3D

Answer

1D

Answer

2D

Answer

4D

Question 4

A 30 year old man presents to the clinic with pain in the eye, watering, redness, and photophobia. Examination of his eyes shows circumcorneal congestion and keratic precipitates. Assertion: Keratic precipitates (KPs) are proteinaceous deposits that can occur in various patterns on the corneal endothelium. Reason: Mutton fat KPs are seen in granulomatous iridocyclitis and are composed of epithelioid cells and macrophages.

Accepted Answer

Both Assertion and Reason are true, and Reason is not the correct explanation for Assertion

Answer

Both Assertion and Reason are true, and Reason is the correct explanation for Assertion

Answer

Assertion is true, but Reason is false

Answer

Assertion is false but reason is true

Question 5

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 6

What does a lensometer measure?

Accepted Answer

The refractive power of corrective lenses

Answer

Corneal topography

Answer

Biochemical constitution of lens

Answer

Power of IOL

Question 7

Sudden loss of vision without pain - Which of the following is NOT a cause?

Accepted Answer

Acute congestive glaucoma

Answer

CRAO

Answer

CSR

Answer

Vitreous Hemorrhage

Question 8

All are true regarding cornea except:

Accepted Answer

The cornea is richly vascular.

Answer

Endothelium help in maintaining dehydrated state

Answer

Oxygen is mostly derived by epithelium directly from the air through tear film

Answer

Corneal thickness is greater at periphery than center

Question 9

What term describes a condition where the axial length of the eye does not match its refractive power?

Accepted Answer

Axial Ametropia

Answer

Anisokonia

Answer

Emmetropia

Answer

Curvature ametropia

Question 10

Which is the most powerful refractive surface of the eye?

Accepted Answer

Cornea

Answer

Conjunctiva

Answer

Vitreous

Answer

Lens

NEET-PG 2015 — Ophthalmology