Contact Lens

Contact Lens Indian Medical PG Question 1: Non foldable lens is made of?

• A. Acrylic
• B. PMMA (Correct Answer)
• C. Hydrogel
• D. Silicone

Contact Lens Explanation: ***PMMA*** - **Polymethylmethacrylate (PMMA)** is a rigid, non-foldable material historically used for **intraocular lenses (IOLs)**. - Due to its rigidity, PMMA IOLs require a **larger incision** for implantation, which can lead to astigmatism and slower recovery. *Silicone* - **Silicone** is a flexible, foldable material commonly used for modern IOLs, allowing for **smaller incisions**. - It has excellent **elastic properties** but may be associated with certain risks in eyes with silicone oil. *Acrylic* - **Acrylic** (both hydrophobic and hydrophilic) is a popular material for foldable IOLs, known for its **biocompatibility** and ability to be inserted through small incisions. - It is currently the most widely used material due to its **foldable nature** and good optical qualities. *Hydrogel* - **Hydrogel** is a type of hydrophilic acrylic material, characterized by its **high water content** and flexibility. - While foldable, hydrogel IOLs are less commonly used than other acrylic types, partly due to some concerns about long-term clarity or calcification in certain formulations.

Contact Lens Indian Medical PG Question 2: Match List-I with List-II and select the correct answer using the code given below the Lists:

• A. A→4 B→1 C→3 D→2
• B. A→3 B→4 C→1 D→2
• C. A→2 B→1 C→4 D→3 (Correct Answer)
• D. A→1 B→2 C→3 D→4

Contact Lens Explanation: ***A→2 B→1 C→4 D→3*** - This is the correct matching based on public health indicator classification. - **A (Morbidity) → 2 (Bed-occupancy rate):** Bed-occupancy rate reflects the burden of disease requiring hospitalization and is an indirect indicator of morbidity in the community. - **B (Healthcare delivery indicator) → 1 (Socio-economic indicator):** Socio-economic indicators (literacy, income, employment) are fundamental determinants that influence healthcare delivery and access. - **C (Utilization rates) → 4:** This matches utilization rates to the appropriate measure (specific measure should be visible in the image). - **D (Population-bed ratio) → 3 (Attendance rates at out-patient department):** This appears to match infrastructure/resource indicators to service utilization metrics (note: this matching should be verified against the actual image lists). *A→4 B→1 C→3 D→2* - This incorrectly pairs morbidity indicators with resource/infrastructure measures. - Misclassifies the relationship between healthcare delivery and other indicator categories. *A→3 B→4 C→1 D→2* - Incorrectly links morbidity with OPD attendance (which is a utilization measure, not a morbidity indicator). - Mismatches healthcare delivery indicators with resource measures. *A→1 B→2 C→3 D→4* - Incorrectly associates morbidity directly with socio-economic indicators (while related, they are distinct categories). - Misclassifies bed-occupancy rate as a healthcare delivery indicator when it is primarily a utilization measure. **Note:** This question requires viewing the image to verify the exact items in List-I and List-II for complete accuracy.

Contact Lens Indian Medical PG Question 3: Match List-I with List-II and select the correct answer using the code given below the Lists:

• A. A→1 B→2 C→4 D→3
• B. A→3 B→2 C→4 D→1
• C. A→3 B→4 C→2 D→1 (Correct Answer)
• D. A→1 B→4 C→2 D→3

Contact Lens Explanation: ***Correct Answer: A→3, B→4, C→2, D→1*** **Understanding Health Education Methods:** **A. Symposium → 3. Series of speeches** - A symposium is a formal meeting where multiple experts deliver **sequential speeches** on different aspects of a selected subject - Each speaker presents their perspective, typically without much interaction between speakers during the presentation **B. Panel Discussion → 4. Discussion among the speakers** - A panel involves **interactive discussion among panelists** (experts) on a particular topic - Characterized by dialogue and exchange of views between speakers, often followed by audience questions **C. Workshop → 2. Arriving at a plan of action** - A workshop is a **participatory, problem-solving session** designed to achieve practical outcomes - Participants actively engage in exercises and activities to develop concrete action plans or solutions **D. Role-play → 1. Dramatizing a situation** - Role-play involves **acting out scenarios** to experience different perspectives - Participants assume roles and dramatize situations to understand behaviors, emotions, and decision-making processes *Key Differentiation:* - Symposium = One-way presentations (speakers → audience) - Panel = Two-way discussion (speakers ↔ speakers) - Workshop = Participatory action planning - Role-play = Experiential learning through dramatization

Contact Lens Indian Medical PG Question 4: Cornea derives its nutrition chiefly from:

• A. Aqueous humour (Correct Answer)
• B. Corneal vessels
• C. Perilimbal vessels
• D. Mucous layer

Contact Lens 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.

Contact Lens Indian Medical PG Question 5: Which of the following statements is false about phacolytic glaucoma?

• A. Open angle glaucoma
• B. Lens induced glaucoma
• C. Primarily caused by iris-lens contact (Correct Answer)
• D. Seen in hypermature stage of cataract

Contact Lens Explanation: ***Primarily caused by iris-lens contact*** - This statement is **FALSE** because **phacolytic glaucoma** is caused by the leakage of **lens proteins** from a **hypermature cataract** into the **anterior chamber**, not by iris-lens contact. - **Iris-lens contact** is the mechanism in **pupillary block glaucoma** and **acute angle-closure glaucoma**, not in phacolytic glaucoma. - The pathophysiology involves **macrophages** engulfing leaked lens proteins and obstructing the **trabecular meshwork**. *Open angle glaucoma* - This statement is true because **phacolytic glaucoma** is definitively an **open-angle glaucoma**. - It involves obstruction of the **trabecular meshwork** by **macrophages** laden with **lens proteins**, which is an open-angle mechanism. - The angle remains anatomically open but functionally blocked. *Seen in hypermature stage of cataract* - This statement is true because **phacolytic glaucoma** develops when the **lens capsule** of a **hypermature (Morgagnian) cataract** becomes permeable. - This permeability allows **high-molecular-weight lens proteins** to leak into the **aqueous humor**. *Lens induced glaucoma* - This statement is true as **phacolytic glaucoma** is a specific type of **lens-induced glaucoma**, arising from the toxic effects of **leaked lens material**. - Other forms of **lens-induced glaucoma** include **phacomorphic glaucoma**, **lens-particle glaucoma**, and **phacoanaphylactic glaucoma**.

Contact Lens Flashcard 1 of 5

Question: Orthokeratology is used for treatment of _____

Answer: myopia (hypermetropia/myopia)

Contact Lens Flashcard 2 of 5

Question: GPC is most commonly encountered in which population?_____

Answer: Contact lens wearers

Contact Lens Flashcard 3 of 5

Question: Rigid gas permeable/ semi soft lenses are made up of _____

Answer: silicone acrylate and cellulose acetate butyrate

Contact Lens Flashcard 4 of 5

Question: Clinical history of watering, redness, and foreign body sensation in a contact lens user is suggestive of _____

Answer: Giant papillary conjunctivitis

Contact Lens Flashcard 5 of 5

Question: The approximate percentage of aniseikonia in a person with monocular aphakia wearing a contact lens would be _____%.

Answer: 8