For laser iridotomy which laser is used?
Optic disc changes of retinitis pigmentosa:
Herbert's pits are seen in:
Rosette cataract is seen after:
Cornea derives its nutrition chiefly from:
Sarcoidosis is associated with
Campimetry is used to measure:
True about Mooren's ulcer:
A child presents with night blindness, delayed dark adaptation. Which investigation is to be done further to confirm the diagnosis?
Which of the following is true about pterygium?
FMGE 2018 - Ophthalmology FMGE Practice Questions and MCQs
Question 11: For laser iridotomy which laser is used?
- A. Nd YAG laser (Correct Answer)
- B. Argon laser
- C. CO2 laser
- D. Excimer laser
Explanation: ***Nd YAG laser*** - The **Nd:YAG laser** is the **primary laser used for laser iridotomy** due to its ability to create precise perforations in the iris. - This laser operates with a **photodisruptive mechanism**, generating plasma formation that effectively creates an opening in the iris. - It is the **treatment of choice for angle-closure glaucoma** and pupillary block. *Argon laser* - The **argon laser** was historically used for iridotomy but is now less commonly the primary choice due to its thermal effect causing more inflammation and scarring. - It is sometimes used in **sequential laser iridotomy** (argon first to thin the iris, followed by Nd:YAG to perforate) in cases where the iris is very thick or heavily pigmented. - Also used for **peripheral iridoplasty** and other thermal applications. *CO2 laser* - **CO2 lasers** are primarily used for **tissue ablation** in surgical procedures, particularly on the skin, eyelid lesions, or in general surgery. - They are **not suitable** for precise intraocular procedures like iridotomy due to their infrared wavelength (10,600 nm) and poor penetration through aqueous humor. *Excimer laser* - **Excimer lasers** are primarily used in **refractive surgery** (e.g., LASIK, PRK) to reshape the cornea. - They work by **photoablation** at 193 nm wavelength, precisely removing tissue layer by layer, and are not designed for creating an opening in the iris.
Question 12: Optic disc changes of retinitis pigmentosa:
- A. Hyperemia of disc
- B. Consecutive optic atrophy (Correct Answer)
- C. No significant change
- D. Blurring of disc margins
Explanation: **Consecutive optic atrophy** - In **retinitis pigmentosa**, the progressive degeneration of photoreceptors and retinal pigment epithelium leads to secondary or **consecutive optic atrophy**. - This atrophy is characterized by a **pale, waxy optic disc** due to loss of retinal ganglion cell axons and glia. *Hyperemia of disc* - **Hyperemia of the optic disc** indicates **inflammation** or **swelling** of the optic nerve head, such as in optic neuritis or papilledema. - This is not a typical feature of retinitis pigmentosa, which involves retinal degeneration, not acute inflammation of the optic nerve. *No significant change* - As **retinitis pigmentosa** progresses, significant changes occur in the retina and optic nerve, including **pigmentary deposits**, **vascular attenuation**, and **optic disc pallor**. - Therefore, stating no significant change would be incorrect as the disease significantly alters the fundus appearance. *Blurring of disc margins* - **Blurring of the optic disc margins** is a hallmark sign of **papilledema** (swelling due to increased intracranial pressure) or an acutely inflamed optic nerve head. - This is distinct from the **optic atrophy** seen in retinitis pigmentosa, which typically involves clear but pale disc margins.
Question 13: Herbert's pits are seen in:
- A. Chlamydial conjunctivitis (Correct Answer)
- B. Gonococcal conjunctivitis
- C. Vernal conjunctivitis
- D. Atopic conjunctivitis
Explanation: ***Chlamydial conjunctivitis*** - **Herbert's pits** are pathognomonic for **trachoma**, a chronic form of chlamydial conjunctivitis caused by *Chlamydia trachomatis* serovars A-C. - They represent healed **follicles** on the superior tarsal conjunctiva, leading to characteristic stellate or linear scarring. *Gonococcal conjunctivitis* - This is an **acute, severe bacterial infection** that typically causes copious purulent discharge and significant edema. - It does not lead to the formation of Herbert's pits, which are sequelae of chronic follicular inflammation. *Vernal conjunctivitis* - A form of chronic allergic conjunctivitis, characterized by **"cobblestone papillae"** on the upper tarsal conjunctiva and **Horner-Trantas dots** at the limbus. - It is not associated with Herbert's pits; its pathophysiology involves mast cell degranulation and allergic inflammation. *Atopic conjunctivitis* - This is often seen in individuals with **atopic dermatitis, asthma, or allergic rhinitis**, presenting with itching, redness, tearing, and sometimes corneal complications. - It does not manifest with follicles or subsequent scarring like Herbert's pits, which are specific to trachoma.
Question 14: Rosette cataract is seen after:
- A. Infection
- B. Penetrating injury to eye
- C. Copper foreign body in eye
- D. Blunt trauma to eye (Correct Answer)
Explanation: ***Blunt trauma to eye*** - **Rosette cataract** is a classic finding following **blunt ocular trauma**, often due to the concussive force on the lens. - The characteristic **flower-petal or star-shaped opacity** forms in the anterior and/or posterior subcapsular regions of the lens. *Infection* - Ocular infections can lead to various complications like **uveitis** or **endophthalmitis**, but **rosette cataract** is not a typical direct sequela. - While inflammation can cause cataracts, they usually present as **inflammatory cataracts** rather than the specific rosette pattern. *Penetrating injury to eye* - **Penetrating injuries** to the eye often lead to **traumatic cataracts** due to direct lens capsule rupture. - These cataracts are typically focal and can progress rapidly, but the morphology is not usually described as a **rosette pattern** unless secondary to significant blunt force component. *Copper foreign body in eye* - A **copper foreign body** in the eye can cause **chalcosis oculi**, leading to a characteristic greenish-brown discoloration and a **sunflower cataract**. - This type of cataract has a distinct appearance from a **rosette cataract**, with a diffuse radial pattern rather than a focal star shape.
Question 15: Cornea derives its nutrition chiefly from:
- A. Aqueous humour (Correct Answer)
- B. Corneal vessels
- C. Perilimbal vessels
- D. Mucous layer
Explanation: ***Aqueous humour*** - The cornea is **avascular**, meaning it lacks its own blood vessels, and thus relies on the **aqueous humor** for metabolic support. - The aqueous humor, located in the anterior chamber, provides **glucose, amino acids, and oxygen** to the posterior surface of the cornea. *Corneal vessels* - The **cornea is avascular** under normal physiological conditions; the presence of corneal vessels (neovascularization) is typically a sign of pathology. - This avascularity is crucial for maintaining corneal transparency and optimal vision. *Perilimbal vessels* - Perilimbal vessels (at the limbus, the junction between cornea and sclera) primarily supply the **periphery of the cornea** and the limbal stem cell niche, not the entire cornea's main nutritional needs. - While they contribute some oxygen and nutrients, the **aqueous humor** is the predominant source for the central and posterior cornea. *Mucous layer* - The mucous layer, part of the tear film, primarily functions in **lubrication and adhesion** of the tear film to the corneal surface. - While it contains some dissolved oxygen from the atmosphere to supply the anterior cornea, its role in nutrient supply (glucose, amino acids) is **minimal** compared to the aqueous humor.
Question 16: Sarcoidosis is associated with
- A. Keratitis
- B. Cataract
- C. Anterior uveitis (Correct Answer)
- D. Ectopia lentis
Explanation: ***Anterior uveitis*** - **Anterior uveitis**, particularly chronic granulomatous anterior uveitis, is the most common ocular manifestation of **sarcoidosis**. - It results from **non-caseating granulomas** affecting the iris and ciliary body. - Sarcoidosis can also cause intermediate uveitis, posterior uveitis, and panuveitis, but anterior uveitis is most frequently seen. - Characteristic findings include mutton-fat keratic precipitates and iris nodules (Koeppe and Busacca nodules). *Keratitis* - **Keratitis** (inflammation of the cornea) is less commonly associated with sarcoidosis compared to uveitis. - While ocular sarcoidosis can rarely cause interstitial keratitis or band keratopathy, direct corneal inflammation is not a hallmark feature. *Cataract* - **Cataracts** are not directly caused by sarcoidosis itself, but can be a complication of chronic uveitis or prolonged corticosteroid treatment. - The disease process of sarcoidosis does not primarily involve cataract formation. *Ectopia lentis* - **Ectopia lentis** (lens dislocation) is a rare condition usually associated with genetic disorders like **Marfan syndrome** or homocystinuria. - It is not a recognized ocular manifestation of sarcoidosis.
Question 17: Campimetry is used to measure:
- A. Squint
- B. Field of Vision (Correct Answer)
- C. Pattern of retina
- D. Malignant melanoma
Explanation: ***Field of Vision*** - **Campimetry** is a diagnostic test specifically designed to map and assess a person's **field of vision**, identifying blind spots or areas of diminished sight. - This technique is crucial for detecting and monitoring conditions that affect the optic nerve or visual pathways, such as **glaucoma** or neurological disorders. *Squint* - A **squint**, also known as strabismus, refers to a misalignment of the eyes. - Its assessment primarily involves tests of **ocular motility** and alignment, such as the cover test, rather than perimetry. *Pattern of retina* - The **pattern of the retina** is evaluated through direct visualization using an **ophthalmoscope** or other retinal imaging techniques like fundus photography or optical coherence tomography (OCT). - These methods provide structural information about the retina, not its functional visual field. *Malignant melanoma* - **Malignant melanoma** (in the context of the eye) is a tumor that can affect various parts of the eye, including the choroid, iris, or conjunctiva. - Its diagnosis involves clinical examination, imaging studies (**ultrasound**, OCT, **fluorescein angiography**), and sometimes biopsy, not primarily visual field testing.
Question 18: True about Mooren's ulcer:
- A. Bilateral in majority of cases
- B. Affects cornea (Correct Answer)
- C. Sudden loss of vision
- D. Painless
Explanation: ***Affects cornea*** - **Mooren's ulcer** is a rare, severe, and idiopathic chronic **ulcerative keratitis** that primarily affects the cornea. - It involves a progressive **peripheral corneal stromal thinning** and ulceration, often extending circumferentially and centrally. *Bilateral in majority of cases* - Mooren's ulcer is **unilateral in approximately 60-80%** of cases, making bilateral presentation less common. - While it can be bilateral, especially in a more severe form, it's not the majority presentation. *Sudden loss of vision* - The vision loss associated with Mooren's ulcer is typically **gradual and progressive**, due to increasing corneal thinning, scarring, and astigmatism. - **Sudden vision loss** is not a characteristic feature of this condition and would suggest other acute pathologies. *Painless* - Mooren's ulcer is often associated with **significant pain**, **photophobia**, and **lacrimation**. - The pain can be severe and debilitating, stemming from the inflammatory process and corneal nerve involvement.
Question 19: A child presents with night blindness, delayed dark adaptation. Which investigation is to be done further to confirm the diagnosis?
- A. ERG (Correct Answer)
- B. Retinoscopy
- C. Dark adaptometry
- D. EOG
Explanation: ***ERG*** - **Electroretinography (ERG)** measures the electrical responses of various retinal cells, including **rods** and **cones**, to light stimuli. - In conditions like **retinitis pigmentosa** which cause night blindness and delayed dark adaptation, ERG will show characteristic abnormal or extinguished responses, confirming retinal dysfunction. *Retinoscopy* - **Retinoscopy** is an objective method to assess the refractive error of the eye by observing the light reflex from the retina. - It does not directly evaluate the functional integrity of photoreceptors or diagnose conditions causing **night blindness**. *Dark adaptometry* - **Dark adaptometry** measures the time it takes for the eye to adapt to dim light after exposure to bright light, quantifying the function of **rod photoreceptors**. - While it can *detect* delayed dark adaptation, it is a functional test that assesses the symptom, not the underlying cause provided by ERG. *EOG* - **Electrooculography (EOG)** measures the potential difference between the cornea and the retina, primarily assessing the function of the **retinal pigment epithelium (RPE)**. - While useful for conditions like **Best's disease**, it is less direct for evaluating generalized rod dysfunction causing night blindness compared to ERG.
Question 20: Which of the following is true about pterygium?
- A. Fatty deposition of sclera
- B. Conjunctival invasion making a flap over cornea (Correct Answer)
- C. Inflammation of cornea
- D. Dead epithelial debris accumulation
Explanation: ***Conjunctival invasion making a flap over cornea*** - A **pterygium** is characterized by the growth of **fibrovascular tissue** from the conjunctiva onto the cornea. - This growth typically forms a **triangular flap**, with its apex extending towards the center of the corneal surface. *Fatty deposition of sclera* - This description is more indicative of **pinguecula**, which is a **yellowish, fatty deposit** on the conjunctiva, usually on the nasal side, but it does not invade the cornea. - Unlike pterygium, a **pinguecula** remains confined to the conjunctiva and does not grow across the limbus onto the cornea. *Inflammation of cornea* - While a pterygium can sometimes cause irritation or inflammation, its primary characteristic is a **degenerative growth of tissue**, not primarily an inflammatory condition of the cornea itself. - **Keratitis** refers to inflammation of the cornea, which can have various causes, but it is not the defining feature of pterygium. *Dead epithelial debris accumulation* - The accumulation of dead epithelial debris is not the principal histological feature of a pterygium. - Pterygium involves **hyperplasia of conjunctival epithelium** and **subepithelial fibrovascular tissue growth**, not merely dead cell accumulation.