Which structures are most commonly involved in a ciliary staphyloma?
Coloboma, most common site?
Expulsive hemorrhage in cataract surgery is from?
What is a potential ocular complication caused by alkali exposure?
Corneal tattooing is done by ?
Iris coloboma is most common in which location?
NEET-PG 2012 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 61: Which structures are most commonly involved in a ciliary staphyloma?
- A. Choroid and sclera
- B. Cornea and conjunctiva
- C. Iris and sclera
- D. Ciliary body and sclera (Correct Answer)
Explanation: ***Ciliary body and sclera*** - A **staphyloma** is a localized bulging of the outer coat of the eye (sclera or cornea) lined internally by uveal tissue. - A **ciliary staphyloma** specifically involves the **ciliary body** and **sclera** at the region of the ciliary body, typically presenting as a dark bluish bulge at the limbal or perilimbal area. - This occurs due to weakening and ectasia of the sclera with prolapse of the underlying ciliary body, commonly seen following scleritis, perforating injuries, or surgeries. *Choroid and sclera* - This combination describes a **posterior staphyloma**, which occurs at the posterior pole of the eye, commonly seen in pathological myopia. - While medically accurate for posterior type, it does not describe a **ciliary staphyloma**. *Iris and sclera* - An **anterior staphyloma** primarily involves bulging of the **cornea** with incarceration of iris tissue, rather than sclera alone. - It occurs after corneal perforation with iris prolapse. *Cornea and conjunctiva* - This does not describe a staphyloma. Bulging of the cornea alone is termed **keratectasia** or **keratoconus**. - The **conjunctiva** is a superficial membrane and is not a structural component of staphyloma formation.
Question 62: Coloboma, most common site?
- A. Superotemporal
- B. Inferonasal (Correct Answer)
- C. Inferotemporal
- D. Superonasal
Explanation: ***Inferonasal*** - This is the **most common site** for coloboma because it corresponds to the location of the **fetal optic fissure** (choroidal fissure) during development. - Coloboma results from the **incomplete closure** of the fetal optic fissure, which normally occurs around the fifth to seventh week of gestation. *Superotemporal* - While coloboma can occur in various locations, the **superotemporal quadrant** is not the typical site. - Colobomas are usually found in areas consistent with the path of the optic fissure. *Inferotemporal* - This location is less common for colobomas compared to the inferonasal region. - The inferotemporal region does not align with the usual embryological fusion line of the optic fissure. *Superonasal* - Colobomas in the **superonasal quadrant** are rare. - This area is typically unaffected because it is not part of the fetal optic fissure's normal closure pathway.
Question 63: Expulsive hemorrhage in cataract surgery is from?
- A. Vortex vein
- B. Choroidal vein
- C. Ciliary artery (Correct Answer)
- D. None of the options
Explanation: ***Ciliary artery*** - Expulsive hemorrhage is a rare but devastating complication, typically resulting from the rupture of a **posterior ciliary artery** within the choroid. - This arterial rupture leads to a sudden, massive increase in intraocular pressure and extrusion of intraocular contents. *Vortex vein* - **Vortex veins** drain the choroid, and while their rupture could lead to hemorrhage, it is less likely to cause the highly pressurized, expulsive nature of a choroidal hemorrhage. - Hemorrhage from a vortex vein is generally less severe and less rapid in onset compared to arterial bleeding. *Choroidal vein* - **Choroidal veins** are part of the venous drainage system; bleeding from these vessels would typically be lower pressure and less likely to cause an expulsive hemorrhage. - Venous bleeds are generally slower and do not generate the rapid, violent pressure increase characteristic of expulsive hemorrhage. *None of the options* - This option is incorrect because the rupture of a ciliary artery is the direct cause of expulsive hemorrhage. - The other options are incorrect for the reasons stated above.
Question 64: What is a potential ocular complication caused by alkali exposure?
- A. Symblepharon (Correct Answer)
- B. Papilloedema
- C. Optic neuritis
- D. Retinal detachment
Explanation: ***Symblepharon*** - **Symblepharon** is the **adhesion of the palpebral conjunctiva to the bulbar conjunctiva**. It is a common long-term complication of severe alkali burns to the eye, reflecting significant tissue damage and cicatrization. - Alkali causes **liquefactive necrosis**, deeply penetrating ocular tissues and leading to extensive inflammation, scarring, and subsequent adhesion formation due to the destruction of the conjunctival surface. *Papilloedema* - **Papilloedema** refers to **optic disc swelling due to increased intracranial pressure**, not a direct result of ocular surface trauma or chemical exposure. - While systemic conditions can cause papilloedema, it is unrelated to the local effects of an **alkali burn**. *Optic neuritis* - **Optic neuritis** is an **inflammation of the optic nerve**, often associated with demyelinating diseases like multiple sclerosis. - It results in **vision loss** and pain with eye movement but is not a complication of external ocular chemical burns. *Retinal detachment* - **Retinal detachment** occurs when the **retina separates from the underlying retinal pigment epithelium**, leading to significant vision loss. - This condition is typically caused by trauma, vitreous traction, or retinal tears, and is not a direct consequence of an **alkali burn to the anterior segment of the eye**.
Question 65: Corneal tattooing is done by ?
- A. Titanium chloride
- B. Aluminium chloride
- C. India ink (Correct Answer)
- D. Gold chloride
Explanation: ***India ink*** - **India ink (carbon black)** is the traditional and most commonly used pigment for corneal tattooing due to its stable black color and inert properties. - It is applied to the **corneal stroma** to mask corneal opacities or for cosmetic purposes in cases of unsightly leucomatous corneal scars. - India ink has been the **gold standard** for corneal tattooing since the 19th century. *Gold chloride* - While **gold preparations** (including platinum-gold) have been used historically for corneal tattooing, they are much less common than India ink. - Gold chloride specifically is not the standard or preferred agent for this procedure. - India ink remains the pigment of choice due to better cosmetic results and established safety profile. *Titanium chloride* - **Titanium chloride** is a corrosive chemical and is not used in corneal tattooing; its application would cause severe damage to the delicate corneal tissue. - It is primarily used in industrial applications and chemical synthesis, not in ophthalmic procedures. *Aluminium chloride* - **Aluminium chloride** is an astringent and antiseptic, often used in dermatological products, but it is not a tattooing pigment for the cornea. - Its chemical properties would be highly irritating to the eye and potentially damaging to corneal cells.
Question 66: Iris coloboma is most common in which location?
- A. Superotemporal
- B. Inferonasal (Correct Answer)
- C. Inferotemporal
- D. Superonasal
Explanation: ***Inferonasal*** - **Iris coloboma** most commonly occurs in the **inferonasal quadrant** (at approximately the **6 o'clock position**) - This location corresponds to the site of the **embryonic fetal fissure** (choroidal fissure), which normally closes during the **5th to 7th week of gestation** - When the fetal fissure fails to close completely, it results in a **keyhole-shaped defect** in the iris, and potentially involves other ocular structures (ciliary body, choroid, retina, optic nerve) along the same inferonasal axis - This is a well-established anatomical pattern seen in **congenital colobomas** *Inferotemporal* - The inferotemporal quadrant is **not the typical location** for iris coloboma - Embryologically, the fetal fissure does not extend into the temporal region, making colobomas in this location extremely rare - Colobomas outside the inferonasal location are usually **atypical colobomas** caused by different mechanisms *Superotemporal* - The superotemporal quadrant is **not associated** with the fetal fissure closure pathway - Colobomas in this location would be considered atypical and not related to embryonic fissure closure defects - This is not a common presentation for congenital iris coloboma *Superonasal* - The superonasal quadrant is also **not part of the fetal fissure pathway** - While superior colobomas can occasionally occur as atypical variants, they do not represent the classic congenital coloboma pattern - The embryological basis for typical coloboma formation does not involve the superior regions of the eye