Microbiology
1 questionsRhabditiform larvae are seen in which of the following?
NEET-PG 2012 - Microbiology NEET-PG Practice Questions and MCQs
Question 691: Rhabditiform larvae are seen in which of the following?
- A. Taenia solium
- B. Strongyloides stercoralis (Correct Answer)
- C. Diphyllobothrium latum
- D. Trichinella spiralis
Explanation: ***Strongyloides stercoralis*** - *Strongyloides stercoralis* is unique among intestinal nematodes in that it can produce **rhabditiform larvae** in the stool. These larvae can then mature into infective **filariform larvae** either in the soil or within the host. - The presence of **rhabditiform larvae in fresh stool samples** is a key diagnostic feature differentiating *Strongyloides* from other parasitic infections that typically shed eggs. *Taenia solium* - *Taenia solium* (pork tapeworm) is transmitted by **ingesting undercooked pork** containing cysticerci. - The parasite is diagnosed by finding **eggs or proglottids in stool**, not rhabditiform larvae. *Diphyllobothrium latum* - *Diphyllobothrium latum* (fish tapeworm) infects humans upon consumption of **undercooked or raw freshwater fish**. - Diagnosis is made by identifying characteristic **operculated eggs in stool samples**, which do not contain rhabditiform larvae. *Trichinella spiralis* - *Trichinella spiralis* causes trichinosis, usually acquired by eating **undercooked meat infected with encysted larvae**. - This parasite is typically diagnosed by **muscle biopsy** showing encysted larvae or serological tests, as it does not produce rhabditiform larvae in stool.
Ophthalmology
9 questionsHow is dioptric power related to focal length?
What is the definition of the visual axis in relation to the eye?
Which of the following is a known complication of vernal keratoconjunctivitis?
Satellite nodules are typically associated with which of the following conditions?
Recurrent anterior uveitis with increased intraocular tension is seen in which of the following conditions?
Which of the following conditions is least likely to be associated with neovascular glaucoma?
Laser iridotomy is done in?
What type of deposit is commonly associated with age-related macular degeneration?
What does extraretinal fibrovascular proliferation at the ridge indicate?
NEET-PG 2012 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 691: How is dioptric power related to focal length?
- A. Directly to square of focal length
- B. Inversely to focal length (Correct Answer)
- C. Directly to focal length
- D. Inversely to square of focal length
Explanation: ***Inversely to focal length*** - Dioptric power, measured in **diopters**, is defined as the **reciprocal of the focal length** when the focal length is expressed in meters. - This inverse relationship means that a shorter focal length corresponds to a higher dioptric power, indicating stronger light-bending ability. *Directly to square of focal length* - The relationship between dioptric power and focal length is **linear** (inverse), not squared. - There is no direct proportional relationship with the square of the focal length in optical power calculations. *Directly to focal length* - Dioptric power is **inversely proportional** to focal length, not directly proportional. - As focal length increases, the power of the lens to converge or diverge light decreases. *Inversely to square of focal length* - Dioptric power is inversely proportional to the **focal length itself**, not its square. - The square of the focal length is not typically used in defining the dioptric power of a lens.
Question 692: What is the definition of the visual axis in relation to the eye?
- A. Line from the object to the fovea (Correct Answer)
- B. Line from the center of the lens to the cornea
- C. Line from the center of the cornea to the center of the lens
- D. None of the options
Explanation: ***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.
Question 693: Which of the following is a known complication of vernal keratoconjunctivitis?
- A. Keratoconus (Correct Answer)
- B. Retinal detachment
- C. Vitreous hemorrhage
- D. Cataract
Explanation: ***Keratoconus*** - **Vernal keratoconjunctivitis (VKC)** is a chronic allergic eye condition associated with persistent eye rubbing, which can lead to thinning and bulging of the cornea, a condition known as **keratoconus**. - Long-term inflammation and mechanical stress from allergic reactions and *eye rubbing* contribute to the corneal structural changes seen in keratoconus. - This is the **most common and well-recognized complication** of VKC. *Cataract* - While cataracts can occur in VKC patients (particularly from **chronic topical steroid use** or severe disease with shield ulcers), they are **less common than keratoconus** as a direct complication. - Keratoconus remains the more characteristic and frequently encountered complication specifically associated with the mechanical trauma of eye rubbing in VKC. *Retinal detachment* - **Retinal detachment** is a condition where the retina separates from its underlying support tissues and is typically associated with trauma, high myopia, or diabetic retinopathy, not VKC. - VKC primarily affects the conjunctiva and cornea, and its inflammatory processes do not directly cause retinal detachment. *Vitreous hemorrhage* - **Vitreous hemorrhage** involves bleeding into the gel-like substance that fills the eye and is commonly caused by conditions like diabetic retinopathy or retinal tears, not VKC. - VKC does not involve the posterior segment of the eye in a way that would lead to vitreous hemorrhage.
Question 694: Satellite nodules are typically associated with which of the following conditions?
- A. Tuberculosis
- B. Sarcoidosis
- C. Viral ulcer
- D. Fungal corneal ulcer (Correct Answer)
Explanation: ***Fungal corneal ulcer*** - **Satellite lesions** (small, isolated infiltrates surrounding a larger central ulcer) are a characteristic feature of **fungal keratitis**, indicating the spread of fungal hyphae. - Unlike bacterial ulcers, fungal ulcers often have a feathery, indistinct margin and can be slow-growing. *Tuberculosis* - Ocular tuberculosis can present with granulomatous inflammation, often involving the uvea or retina, but **satellite nodules** around a corneal ulcer are not typical. - Corneal involvement in tuberculosis is rare and usually manifests as interstitial keratitis or phlyctenular keratitis. *Sarcoidosis* - Ocular sarcoidosis commonly causes **uveitis**, conjunctival nodules, or retinal vasculitis. - While it can cause corneal deposits or band keratopathy, it does not typically present with satellite lesions around a primary corneal ulcer. *Viral ulcer* - Viral corneal ulcers, particularly those caused by **herpes simplex virus**, often present as **dendritic ulcers** or geographic ulcers. - Although epithelial lesions can spread, the distinct **satellite infiltrates** in the stroma seen in fungal infections are not characteristic of viral keratitis.
Question 695: Recurrent anterior uveitis with increased intraocular tension is seen in which of the following conditions?
- A. Posner-Schlossman syndrome (Correct Answer)
- B. Foster-Kennedy syndrome
- C. Vogt-Koyanagi-Harada syndrome
- D. Fuchs heterochromic iridocyclitis
Explanation: ***Posner-Schlossman syndrome*** - Characterized by **recurrent, unilateral, non-granulomatous anterior uveitis** associated with markedly **elevated intraocular pressure (IOP)**. - The condition is also known as **glaucomatocyclitic crisis**, highlighting the episodic inflammation and glaucoma. - Key features include **acute attacks** lasting hours to weeks with **dramatic IOP elevation** (often >40 mmHg). *Foster-Kennedy syndrome* - This syndrome is defined by ipsilateral **optic atrophy**, contralateral **papilledema**, and often **anosmia**, typically due to a frontal lobe tumor. - It does not involve anterior uveitis or primary elevated intraocular tension. - This is a neuro-ophthalmologic syndrome, not an inflammatory ocular condition. *Vogt-Koyanagi-Harada syndrome* - An autoimmune disorder affecting pigmented tissues, leading to **bilateral granulomatous panuveitis**, often with hearing loss, vitiligo, poliosis, and neurological symptoms. - While it involves uveitis, it is typically **bilateral and panuveitis**, not recurrent unilateral anterior uveitis. - IOP may be elevated but not the defining feature with dramatic episodic rises. *Fuchs heterochromic iridocyclitis* - A chronic, **unilateral, low-grade anterior uveitis** with characteristic iris heterochromia. - May have mild IOP elevation but **not recurrent episodic attacks** with marked pressure spikes. - Inflammation is typically **quiet and chronic** rather than acute and recurrent.
Question 696: Which of the following conditions is least likely to be associated with neovascular glaucoma?
- A. Diabetes
- B. Open angle glaucoma (Correct Answer)
- C. CRVO
- D. Eale's disease
Explanation: ***Open angle glaucoma*** ✓ - **Open-angle glaucoma** is a primary **neurodegenerative disease** of the optic nerve, characterized by progressive loss of **retinal ganglion cells** and their axons, leading to characteristic **optic neuropathy** and visual field defects. - It does **NOT** directly cause **neovascularization** or increased VEGF production, which are the underlying mechanisms for **neovascular glaucoma**. - This is the **least likely** association among the given options. *Diabetes* - **Diabetic retinopathy** is a **major cause** of **neovascularization** due to retinal ischemia and increased production of **vascular endothelial growth factor (VEGF)**, which can lead to **neovascular glaucoma**. - **Neovascularization** on the iris (rubeosis iridis) and angle can block aqueous outflow, causing a severe, rapidly progressing form of secondary glaucoma. *CRVO (Central Retinal Vein Occlusion)* - **CRVO** leads to significant retinal ischemia and subsequent release of **VEGF**, which prompts the growth of new, fragile blood vessels. - These new vessels (neovascularization) can grow in the iris and angle, obstructing aqueous humor outflow and causing **neovascular glaucoma**. - **Ischemic CRVO** is one of the **most common causes** of neovascular glaucoma. *Eale's disease* - **Eale's disease** is an **idiopathic occlusive vasculitis** primarily affecting the **peripheral retinal veins**, leading to **retinal ischemia**. - This ischemia stimulates **neovascularization** and the production of **VEGF**, increasing the risk of **neovascular glaucoma** due to the formation of new blood vessels in the anterior chamber.
Question 697: Laser iridotomy is done in?
- A. Pigmentary glaucoma
- B. None of the options
- C. Angle closure glaucoma (Correct Answer)
- D. Open angle glaucoma
Explanation: ***Angle closure glaucoma*** - **Laser iridotomy** creates a small hole in the iris, allowing aqueous humor to flow directly from the posterior to the anterior chamber, thus relieving pupillary block and opening the angle. - This procedure is the definitive treatment to prevent further **angle closure attacks** and is also used prophylactically in eyes at risk. *Open angle glaucoma* - This condition involves an **open angle** but impaired outflow of aqueous humor through the **trabecular meshwork**. - Laser iridotomy is not indicated as it does not address the primary outflow obstruction in the trabecular meshwork. *Pigmentary glaucoma* - This is a type of **open-angle glaucoma** caused by pigment dispersion that clogs the trabecular meshwork, leading to increased intraocular pressure. - While pigment can be released from the iris, the primary issue is the **trabecular meshwork obstruction**, which is not directly resolved by iridotomy. *None of the options* - This option is incorrect because **angle closure glaucoma** is a clear indication for laser iridotomy.
Question 698: What type of deposit is commonly associated with age-related macular degeneration?
- A. Iron
- B. Drusen (Correct Answer)
- C. Lipochrome
- D. Hemosiderine
Explanation: ***Drusen*** - **Drusen** are yellow deposits of extracellular material that accumulate beneath the **retinal pigment epithelium (RPE)**. - Their presence is a hallmark sign of **age-related macular degeneration (AMD)** and can lead to vision loss by disrupting retinal function. *Iron* - While iron can accumulate in ocular tissues in conditions like **siderosis bulbi** (due to retained intraocular foreign bodies), it is not a characteristic deposit of macular degeneration. - Ocular iron deposition typically causes different pathologies, such as retinal dysfunction or glaucoma, rather than AMD. *Lipochrome* - **Lipochrome** refers to a class of pigments, including **lipofuscin**, which can accumulate in cells as a byproduct of cellular metabolism and aging. - Although lipofuscin buildup occurs in the RPE with age, **drusen** are the specific, organized extracellular deposits pathognomonic for macular degeneration. *Hemosiderine* - **Hemosiderin** is an iron-storage complex formed from the breakdown of hemoglobin, found in situations of hemorrhage or chronic bleeding. - It is not a typical deposit found in macular degeneration; its presence in the retina usually indicates a history of retinal hemorrhage.
Question 699: What does extraretinal fibrovascular proliferation at the ridge indicate?
- A. Normal retina
- B. Stage II Retinopathy of Prematurity
- C. Stage III Retinopathy of Prematurity (Correct Answer)
- D. Stage I Retinopathy of Prematurity
Explanation: ***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.