Contact Lens Complications — MCQs
A patient presents with eye pain, redness, and blurred vision after sleeping in contact lenses. Fluorescein staining reveals a corneal ulcer. What is the most appropriate management?
Postoperative complications of cataract surgery are all except?
Interstitial keratitis is associated with all of the following except:
Which of the following is a known complication of vernal keratoconjunctivitis?
What is the most common infection in contact lens users?
Keratitis in contact lens wearers is caused by all except?
A young boy who used to wash his contact lenses in tap water or with unhygienic lens fluid developed keratitis. Microscopy revealed an organism with spiked or star-shaped structures. Identify the correct organism responsible.
In the context of homocystinuria, which direction does the lens typically subluxate?
Regarding Chlamydia infection of the eyes, true statements include the following except:
What does the following image show?
Contact Lens Complications Indian Medical PG Practice Questions and MCQs
Question 1: A patient presents with eye pain, redness, and blurred vision after sleeping in contact lenses. Fluorescein staining reveals a corneal ulcer. What is the most appropriate management?
- A. Topical antibiotics (Correct Answer)
- B. Oral antibiotics
- C. Topical corticosteroids
- D. Saline irrigation
Explanation: ***Topical antibiotics*** - A **corneal ulcer**, especially in a contact lens wearer, is highly suspicious for **bacterial infection**, necessitating immediate and aggressive topical antibiotic therapy. - **Broad-spectrum antibiotics** (e.g., fluoroquinolones) are often started empirically and adjusted based on culture results. *Oral antibiotics* - **Systemic antibiotics** are generally not indicated for uncomplicated bacterial corneal ulcers, as they don't achieve sufficient concentrations in the cornea to be effective. - They may be considered for severe cases with limbal involvement or scleral extension, or if there is a concern for concurrent systemic infection. *Topical corticosteroids* - **Corticosteroids** are contraindicated in the initial management of suspected infectious corneal ulcers because they can suppress the immune response and worsen the infection. - They may be cautiously used later in treatment to reduce inflammation after the infection is well-controlled. *Saline irrigation* - While helpful for removing foreign bodies or debris, **saline irrigation alone** is insufficient to treat a bacterial corneal ulcer. - It does not eradicate the infection and delaying definitive antibiotic treatment can lead to severe complications.
Question 2: Postoperative complications of cataract surgery are all except?
- A. Endophthalmitis
- B. Glaucoma
- C. Scleritis (Correct Answer)
- D. After cataract
Explanation: ***Scleritis*** - **Scleritis** is an inflammatory condition of the sclera, which is the white outer layer of the eye, and is generally not a direct postoperative complication of cataract surgery. - While it can occur in patients with systemic inflammatory diseases, it is not causally linked to cataract surgery itself. *Endophthalmitis* - **Endophthalmitis** is a severe infection of the intraocular fluids (vitreous and aqueous humor) and tissues, representing a rare but devastating complication of cataract surgery. - It typically presents with rapidly progressive vision loss, pain, and hypopyon (pus in the anterior chamber) within days to weeks post-surgery. *Glaucoma* - **Glaucoma** can develop or worsen after cataract surgery due to various mechanisms, such as inflammation leading to trabecular meshwork dysfunction, pupillary block, or retained lens material. - Postoperative intraocular pressure (IOP) elevation can result in optic nerve damage if not promptly managed. *After cataract* - **After cataract**, also known as **posterior capsule opacification (PCO)**, is the most common long-term complication of cataract surgery. - It occurs when residual lens epithelial cells proliferate and migrate onto the posterior lens capsule, causing blurring of vision months to years after surgery, and is typically treated with Nd:YAG laser capsulotomy.
Question 3: Interstitial keratitis is associated with all of the following except:
- A. Syphilis
- B. Acanthamoeba (Correct Answer)
- C. Chlamydia Trachomatis
- D. Herpes Zoster Virus (HZV)
Explanation: ***Acanthamoeba*** - **Acanthamoeba keratitis** is a **suppurative keratitis** characterized by a painful, ring-shaped infiltrate with epithelial ulceration, typically associated with contact lens use and contaminated water exposure. - It causes **ulcerative stromal inflammation**, not the **non-ulcerative deep stromal inflammation** that characterizes classic interstitial keratitis. - **This is NOT a cause of interstitial keratitis.** *Syphilis* - **Congenital syphilis** is the **CLASSIC cause** of bilateral **interstitial keratitis**, often presenting in late childhood with "salmon patch" appearance, photophobia, lacrimation, and eventual ghost vessels. - The inflammation is **non-ulcerative and chronic**, affecting the **deep corneal stroma** with preservation of epithelium. - This is the most important association with interstitial keratitis to remember. *Chlamydia Trachomatis* - **Chlamydia trachomatis** causes **trachoma**, a chronic keratoconjunctivitis leading to **superficial keratitis with pannus formation** (superficial vascularization from the limbus). - The corneal involvement in trachoma is **superficial**, not the deep stromal inflammation seen in classic interstitial keratitis. - While listed in some references, **Chlamydia is NOT a standard cause of interstitial keratitis** in major ophthalmology textbooks. - **Note:** This option is potentially debatable, but Acanthamoeba is the more definitively incorrect answer. *Herpes Zoster Virus (HZV)* - **Herpes zoster ophthalmicus** can lead to **interstitial keratitis** and **disciform keratitis** (immune-mediated stromal inflammation with disc-shaped corneal edema). - Similarly, **HSV (Herpes Simplex Virus)** causes stromal keratitis, a form of interstitial keratitis. - The corneal involvement includes **deep stromal inflammation, scarring**, and potential neurotrophic changes leading to vision impairment.
Question 4: 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 5: What is the most common infection in contact lens users?
- A. Streptococcus
- B. Staphylococcus
- C. Neisseria
- D. Pseudomonas (Correct Answer)
Explanation: ***Pseudomonas*** - **Pseudomonas aeruginosa** is the leading cause of **bacterial keratitis** in contact lens wearers, accounting for 60-70% of culture-positive cases - This bacterium can **adhere to lenses**, form **biofilms**, and thrive in moist lens storage cases - Can cause rapid and severe corneal damage with **corneal ulceration**, potentially leading to **vision loss** *Staphylococcus* - **Staphylococcus aureus** and **Staphylococcus epidermidis** are common commensals of the skin and can cause eye infections, including keratitis and blepharitis - However, in the context of contact lens-related keratitis, **Pseudomonas aeruginosa** remains the primary pathogen for severe corneal infections *Streptococcus* - While various **Streptococcus species** (especially S. pneumoniae) can cause bacterial keratitis, they are less commonly associated with contact lens-related keratitis compared to Pseudomonas - **Streptococcal keratitis** typically occurs in non-contact lens wearers or after trauma *Neisseria* - **Neisseria gonorrhoeae** can cause hyperacute bacterial conjunctivitis with severe purulent discharge, but is not the most common cause of contact lens-related keratitis - **Neisseria meningitidis** can rarely cause conjunctivitis, but these infections usually indicate specific exposure or systemic disease
Question 6: Keratitis in contact lens wearers is caused by all except?
- A. Chlamydia
- B. Aspergillus
- C. Pseudomonas
- D. Pneumococcus (Correct Answer)
Explanation: ***Pneumococcus*** - While *Streptococcus pneumoniae* (Pneumococcus) can cause bacterial keratitis, it is **classically associated with corneal ulcers following trauma** rather than contact lens wear. - In contact lens-related keratitis, Pneumococcus is **significantly less common** compared to *Pseudomonas*, which dominates as the primary bacterial pathogen in this setting. - Pneumococcal keratitis typically presents with a **well-demarcated, dense purulent ulcer with hypopyon**, often following corneal injury. *Pseudomonas* - **_Pseudomonas aeruginosa_** is **the most common cause of bacterial keratitis in contact lens wearers**, accounting for the majority of severe cases. - It thrives in moist environments such as contaminated contact lens cases and solutions, producing **exotoxins and proteases that cause rapid corneal destruction and tissue melt**. - Presents with a **rapidly progressive, dense stromal infiltrate** with a characteristic **ground-glass appearance** and potential for perforation. *Aspergillus* - **_Aspergillus_ species** are an important cause of **fungal keratitis**, particularly associated with contact lens wear, poor lens hygiene, and contaminated lens solutions. - Fungal keratitis presents with **feathery-edged infiltrates, satellite lesions**, and ring-shaped infiltrates, often requiring antifungal therapy. - More common in tropical climates and agricultural settings. *Chlamydia* - **_Chlamydia trachomatis_** is primarily a cause of **trachoma** (chronic follicular conjunctivitis leading to scarring) and **adult inclusion conjunctivitis**. - While it can cause **superficial punctate keratitis and pannus formation** in trachoma, it is **NOT a typical cause of acute suppurative keratitis in contact lens wearers**. - The acute bacterial and fungal keratitis seen in contact lens wearers is a different clinical entity from chlamydial conjunctivitis/keratopathy.
Question 7: A young boy who used to wash his contact lenses in tap water or with unhygienic lens fluid developed keratitis. Microscopy revealed an organism with spiked or star-shaped structures. Identify the correct organism responsible.
- A. Balantidium
- B. Pseudomonas
- C. Acanthamoeba (Correct Answer)
- D. Staphylococcus aureus
Explanation: ***Acanthamoeba*** - *Acanthamoeba* is a **free-living amoeba** found in water, soil, and inadequately disinfected contact lens solutions, specifically linked to **keratitis** in contact lens wearers. - Its characteristic morphology, often described as having **spiked or star-shaped structures**, refers to the **acanthopodia** (spine-like pseudopods) that are distinctive features visible microscopically. *Balantidium* - *Balantidium coli* is a **ciliated protozoan** and primarily causes **intestinal infections** (balantidiasis), not keratitis. - It would be distinguished microscopically by its **large size**, **kidney-shaped macronucleus**, and **cilia**, not spiked structures. *Pseudomonas* - *Pseudomonas aeruginosa* is a **bacterium** and a common cause of **bacterial keratitis**, especially in contact lens wearers, but it is not a protozoan. - Microscopically, it would appear as **rod-shaped bacteria**, not organisms with spiked or star-shaped structures. *Staphylococcus aureus* - *Staphylococcus aureus* is a **bacterium** and a frequent cause of various infections, including **bacterial keratitis**. - Under a microscope, it presents as **Gram-positive cocci in clusters**, not as an amoeba with spiked or star-shaped protrusions.
Question 8: In the context of homocystinuria, which direction does the lens typically subluxate?
- A. Inferotemporal
- B. Inferonasal (Correct Answer)
- C. Superonasal
- D. Superotemporal
Explanation: ***Inferonasal*** - In **homocystinuria**, the **ectopia lentis** (lens subluxation) often occurs due to weakening of the **zonular fibers**. - The classic direction for lens subluxation in homocystinuria is **inferior and nasal**. *Inferotemporal* - While lens subluxation can occur in various directions, **inferotemporal** is not the classic or most common presentation in homocystinuria. - This direction is less specific and does not strongly point to homocystinuria as the underlying cause. *Superonasal* - **Superonasal** dislocation of the lens is more characteristic of **Marfan syndrome**, which is important to differentiate from homocystinuria. - This direction helps distinguish different causes of lens ectopia. *Superotemporal* - **Superotemporal** lens subluxation is the hallmark of **Marfan syndrome**, a genetic connective tissue disorder. - This specific finding is crucial for differential diagnosis in patients presenting with lens ectopia.
Question 9: Regarding Chlamydia infection of the eyes, true statements include the following except:
- A. Penicillin is the treatment (Correct Answer)
- B. Inclusion conjunctivitis is an acute ocular infection caused by sexually transmitted C. trachomatis strains (usually serovars D through K)
- C. Can be cultured
- D. Acute inclusion conjunctivitis typically presents with mucopurulent discharge
Explanation: ***Penicillin is the treatment*** - **Penicillin** is ineffective against *Chlamydia trachomatis* because *Chlamydia* lacks a **peptidoglycan cell wall**, which is the target of penicillin. - The standard treatment for chlamydial infections, including ocular infections, involves **azithromycin** or **doxycycline**. *Inclusion conjunctivitis is an acute ocular infection caused by sexually transmitted C. trachomatis strains (usually serovars D through K)* - **Inclusion conjunctivitis** is indeed caused by sexually transmitted serovars of *Chlamydia trachomatis* (typically **D through K**). - It usually occurs in sexually active adults and can affect neonates through maternal transmission. *Can be cultured* - *Chlamydia* are **obligate intracellular bacteria**, meaning they can only replicate inside host cells. - While they can be grown in cell cultures, this is a specialized technique and not a typical method for routine diagnosis due to its complexity and time-consuming nature. *Acute inclusion conjunctivitis typically presents with mucopurulent discharge* - **Acute inclusion conjunctivitis** is characterized by a **mucopurulent discharge**, along with **follicular conjunctivitis** and sometimes **preauricular lymphadenopathy**. - This discharge results from the inflammatory response to the chlamydial infection in the conjunctiva.
Question 10: What does the following image show?
- A. Anterior uveitis
- B. Membranous conjunctivitis
- C. Pannus (Correct Answer)
- D. Pseudomembranous conjunctivitis
Explanation: ***Pannus*** - The image distinctly shows **new blood vessels growing into the cornea** from the limbus, which is characteristic of pannus formation. This vascularization often accompanies chronic inflammation or hypoxia. - This condition is a hallmark of certain ophthalmic diseases, such as **trachoma** or chronic irritation from prolonged **contact lens wear**. *Anterior uveitis* - Anterior uveitis presents with inflammation of the iris and ciliary body, typically causing **ciliary flush**, **miosis**, and cells/flare in the anterior chamber, which are not the primary features shown. - While uveitis can sometimes lead to corneal changes, the prominent **vascularization extending onto the cornea** is not its defining visual characteristic. *Membranous conjunctivitis* - Membranous conjunctivitis is characterized by the formation of a **true membrane on the conjunctiva** that binds tightly to the underlying epithelium, often caused by severe bacterial infections like *Corynebacterium diphtheriae*. - The image does not show a membrane on the conjunctival surface; instead, it highlights **corneal vascularization**. *Pseudomembranous conjunctivitis* - Pseudomembranous conjunctivitis involves a **fibrinous exudate loosely adherent** to the conjunctiva, which can be peeled off without significant bleeding, as seen in adenoviral conjunctivitis. - The findings in the image, specifically **vascular ingrowth into the cornea**, are not consistent with the appearance of a pseudomembrane on the conjunctiva.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free