FMGE 2018 - Ophthalmology Practice Questions

Q: Keratometry is done to assess:

Curvature of cornea. ***Curvature of cornea*** - **Keratometry** is specifically designed to measure the **radius of curvature of the anterior surface of the cornea**. - This measurement is essential for detecting and quantifying **astigmatism** and for fitting **contact lenses** and calculating **intraocular lens (IOL) power**. *Corneal thickness* - **Corneal thickness** is measured by **pachymetry**, not keratometry. - Pachymetry is used to assess conditions like **corneal edema** or prior to certain refractive surgeries. *Corneal sensation* - **Corneal sensation** is tested using a fine wisp of cotton or a **corneal aesthesiometer**. - This evaluates the integrity of the **corneal nerves** and blink reflex. *Corneal endothelium* - The **corneal endothelium** is assessed using **specular microscopy** to evaluate cell count, size, and shape. - This is important for surgical planning and monitoring **corneal dystrophies**.

Q: For laser iridotomy which laser is used?

Nd YAG laser. ***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.

Q: Optic disc changes of retinitis pigmentosa:

Consecutive optic atrophy. **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.

Q: Herbert's pits are seen in:

Chlamydial conjunctivitis. ***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.

Q: Rosette cataract is seen after:

Blunt trauma to eye. ***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.

Q: Cornea derives its nutrition chiefly from:

Aqueous humour. ***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.

Q: Sarcoidosis is associated with

Anterior uveitis. ***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.

Q: Campimetry is used to measure:

Field of Vision. ***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.

Q: True about Mooren's ulcer:

Affects cornea. ***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.

Q: A child presents with night blindness, delayed dark adaptation. Which investigation is to be done further to confirm the diagnosis?

ERG. ***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 1

Keratometry is done to assess:

Accepted Answer

Curvature of cornea

Answer

Corneal thickness

Answer

Corneal sensation

Answer

Corneal endothelium

Question 2

For laser iridotomy which laser is used?

Accepted Answer

Nd YAG laser

Answer

Argon laser

Answer

CO2 laser

Answer

Excimer laser

Question 3

Optic disc changes of retinitis pigmentosa:

Accepted Answer

Consecutive optic atrophy

Answer

Hyperemia of disc

Answer

No significant change

Answer

Blurring of disc margins

Question 4

Herbert's pits are seen in:

Accepted Answer

Chlamydial conjunctivitis

Answer

Gonococcal conjunctivitis

Answer

Vernal conjunctivitis

Answer

Atopic conjunctivitis

Question 5

Rosette cataract is seen after:

Accepted Answer

Blunt trauma to eye

Answer

Infection

Answer

Penetrating injury to eye

Answer

Copper foreign body in eye

Question 6

Cornea derives its nutrition chiefly from:

Accepted Answer

Aqueous humour

Answer

Corneal vessels

Answer

Perilimbal vessels

Answer

Mucous layer

Question 7

Sarcoidosis is associated with

Accepted Answer

Anterior uveitis

Answer

Keratitis

Answer

Cataract

Answer

Ectopia lentis

Question 8

Campimetry is used to measure:

Accepted Answer

Field of Vision

Answer

Squint

Answer

Pattern of retina

Answer

Malignant melanoma

Question 9

True about Mooren's ulcer:

Accepted Answer

Affects cornea

Answer

Bilateral in majority of cases

Answer

Sudden loss of vision

Answer

Painless

Question 10

A child presents with night blindness, delayed dark adaptation. Which investigation is to be done further to confirm the diagnosis?

Accepted Answer

ERG

Answer

Retinoscopy

Answer

Dark adaptometry

Answer

EOG

FMGE 2018 — Ophthalmology