Vitreoretinal Surgery — MCQs
What is the most common cause of vitreous hemorrhage in diabetic retinopathy?
Pneumoretinopexy is an outpatient procedure in which retinal detachment is sealed with air insufflation. Which of the following gases is used in pneumoretinopexy?
Postoperative complications of cataract surgery are all except?
A diabetic patient presents to you with visual acuity of 6/9 in one eye. Further investigations revealed preretinal hemorrhages with neovascularization at the optic disc. What is the next step in management?
How many incisions are used in the divided system approach of pars plana vitrectomy?
For autopsy, vitreous is preserved in:
Which of the following treatments is not suitable for advanced proliferative diabetic retinopathy with extensive vitreoretinal fibrosis and tractional retinal detachment?
Ocriplasmin is a recombinant protease and it is used to treat:
What is the primary procedure used in retinal detachment surgery?
Consider the following causes of visual loss : 1. Obstruction of the central retinal artery 2. Vitreous and retinal haemorrhage 3. Cataract 4. Retinal detachment Which of the above causes are associated with acute visual loss in a patient?
Vitreoretinal Surgery Indian Medical PG Practice Questions and MCQs
Question 1: What is the most common cause of vitreous hemorrhage in diabetic retinopathy?
- A. Non-proliferative diabetic retinopathy
- B. Proliferative diabetic retinopathy (Correct Answer)
- C. Severe non-proliferative diabetic retinopathy
- D. Diabetic macular edema
Explanation: ***Proliferative diabetic retinopathy*** - **Neovascularization** is the hallmark of proliferative diabetic retinopathy (PDR), where new, fragile blood vessels grow on the surface of the retina and optic disc. - These delicate vessels can easily rupture and bleed into the vitreous humor, leading to a **vitreous hemorrhage**. *Non-proliferative diabetic retinopathy* - This stage is characterized by **microaneurysms**, hemorrhages, and cotton wool spots, but typically lacks significant neovascularization. - While it involves retinal vascular damage, the absence of **newly formed, fragile vessels** makes vitreous hemorrhage less common. *Severe non-proliferative diabetic retinopathy* - This stage shows extensive microvascular abnormalities, including numerous hemorrhages and venular beading, but generally **still no new vessel formation**. - Without the presence of **fragile neovascular membranes**, the risk of significant vitreous hemorrhage is lower compared to PDR. *Diabetic macular edema* - This condition involves **fluid leakage** from damaged retinal vessels into the macula, causing vision loss. - While it's a common complication of diabetes, it primarily causes **macular swelling** and does not directly lead to vitreous hemorrhage.
Question 2: Pneumoretinopexy is an outpatient procedure in which retinal detachment is sealed with air insufflation. Which of the following gases is used in pneumoretinopexy?
- A. Nitrous oxide
- B. Oxygen
- C. Sulfur hexafluoride (Correct Answer)
- D. Carbon dioxide
Explanation: ***Sulfur hexafluoride*** - **Sulfur hexafluoride (SF6)** is a commonly used gas in **pneumatic retinopexy** due to its expansive properties and inertness within the eye. - It provides a **temporary tamponade effect** against the retinal tear, allowing the retina to reattach. - SF6 expands to approximately **twice its injected volume** and provides tamponade for **1-2 weeks**. - **Perfluoropropane (C3F8)** is another gas commonly used in pneumatic retinopexy, which lasts longer (6-8 weeks) but expands more (up to 4 times). *Nitrous oxide* - **Nitrous oxide** is primarily used as an **anesthetic gas** and for pain relief in medical procedures. - It is not suitable for intraocular tamponade due to its rapid absorption and potential to expand existing intraocular gas bubbles dangerously. *Oxygen* - **Oxygen** is essential for cellular respiration and is a fundamental component of the air we breathe. - It is **highly soluble** in intraocular fluids and would be quickly absorbed, making it ineffective for sustained retinal tamponade. *Carbon dioxide* - **Carbon dioxide** is a natural byproduct of metabolism and is used in some surgical contexts (e.g., laparoscopy) to create a working space. - Like oxygen, it is **highly soluble** and would dissipate too quickly to provide the necessary long-term tamponade for retinal reattachment.
Question 3: 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 4: A diabetic patient presents to you with visual acuity of 6/9 in one eye. Further investigations revealed preretinal hemorrhages with neovascularization at the optic disc. What is the next step in management?
- A. Focal laser photocoagulation
- B. Pan-retinal photocoagulation (Correct Answer)
- C. Grid laser photocoagulation
- D. Scleral buckling
Explanation: ***Pan-retinal photocoagulation*** - The presence of **preretinal hemorrhages** and **neovascularization at the optic disc (NVD)** indicates **high-risk proliferative diabetic retinopathy (PDR)**. - **NVD is a high-risk characteristic** for severe vision loss and requires urgent treatment with **pan-retinal photocoagulation (PRP)**. - PRP aims to ablate ischemic peripheral retina, which reduces the production of **VEGF** and other angiogenic factors that stimulate neovascularization. *Focal laser photocoagulation* - This treatment targets discrete leaking microaneurysms in cases of **clinically significant macular edema (CSME)**, which is not the primary issue here. - It is used for **non-proliferative diabetic retinopathy** with macular involvement, not for neovascularization. *Grid laser photocoagulation* - Grid laser is a type of focal laser used for **diffuse macular edema** where specific leaking microaneurysms cannot be identified. - It is not indicated for **neovascularization** or **preretinal hemorrhages**, which are signs of PDR. *Scleral buckling* - **Scleral buckling** is a surgical procedure primarily used to treat **retinal detachment** by indenting the sclera to relieve vitreoretinal traction. - It is not the initial or primary treatment for **proliferative diabetic retinopathy** or **neovascularization**.
Question 5: How many incisions are used in the divided system approach of pars plana vitrectomy?
- A. 1
- B. 3 (Correct Answer)
- C. 2
- D. 4
Explanation: ***3*** - The **divided system approach** of pars plana vitrectomy utilizes **three incisions**: one for the **infusion cannula**, one for the **vitrector**, and one for the **light pipe**. - These three ports provide stable access for instrumentation and fluid infusion during the vitrectomy procedure. *1* - A single incision would be insufficient for a pars plana vitrectomy, as it requires simultaneous delivery of infusion fluid, vitrectomy, and illumination. - This approach is not feasible for the complex maneuvers required in vitrectomy. *2* - Two incisions would typically accommodate the vitrector and light source, but would lack the crucial **infusion cannula** to maintain intraocular pressure and refill the eye as vitreous is removed. - While some specialized single-port techniques exist for very limited procedures, standard pars plana vitrectomy requires three ports for optimal safety and efficacy. *4* - While additional incisions can be made for specific instruments (e.g., foreign body removal, bimanual surgery), the **divided system approach** for standard pars plana vitrectomy fundamentally uses three primary incisions. - More than three incisions are not part of the standard divided system approach but rather auxiliary port placements for advanced or complex cases.
Question 6: For autopsy, vitreous is preserved in:
- A. Phenol
- B. Fluoride (Correct Answer)
- C. Sulphuric acid
- D. Xylol
Explanation: ***Fluoride (Sodium fluoride)*** - **Sodium fluoride** is the preferred preservative for vitreous humor samples collected during autopsy, especially when testing for **alcohol** and **glucose** levels. - It acts as an **enzyme inhibitor**, preventing post-mortem metabolism of glucose and fermentation of alcohol by microorganisms, thus maintaining the sample's integrity. *Phenol* - **Phenol** is an antiseptic and disinfectant often used in tissue preservation for histological examination, but it is not typically used for vitreous humor to preserve metabolites like glucose or alcohol. - It can interfere with some analytical methods used for vitreous analysis. *Sulphuric acid* - **Sulphuric acid** is a strong acid that would cause significant denaturation of proteins and alteration of the chemical composition of vitreous humor. - It is not suitable for preserving biological samples for most analyses, especially for fragile metabolites such as glucose. *Xylol* - **Xylol** (xylene) is a common solvent used in histology for clearing tissues (removing alcohol) before paraffin embedding, making it unsuitable for direct preservation of body fluids like vitreous humor. - It would dissolve cellular components and denature proteins, rendering the sample useless for chemical analysis.
Question 7: Which of the following treatments is not suitable for advanced proliferative diabetic retinopathy with extensive vitreoretinal fibrosis and tractional retinal detachment?
- A. Removal of epiretinal membrane
- B. Photocoagulation (Correct Answer)
- C. Vitrectomy
- D. Reattachment of detached or torn retina
Explanation: ***Photocoagulation*** - The question asks for a treatment **not suitable** for **advanced proliferative diabetic retinopathy** with **extensive vitreoretinal fibrosis** and **tractional retinal detachment (TRD)**. - **Panretinal photocoagulation (PRP)** is a laser treatment used to ablate ischemic peripheral retina and prevent neovascularization in proliferative diabetic retinopathy. However, it is a **preventive measure** used in **earlier stages of PDR** before the development of extensive fibrosis and tractional detachment. - Once **tractional retinal detachment** has developed with **extensive vitreoretinal fibrosis**, photocoagulation alone **cannot relieve the mechanical traction** on the retina or **reattach the detached retina**. At this advanced stage, **surgical intervention is required**. - While endolaser photocoagulation can be performed **during vitrectomy** as an adjunctive measure, standalone photocoagulation is not suitable as a primary treatment for established TRD with extensive fibrosis. *Vitrectomy* - **Pars plana vitrectomy** is the **definitive surgical treatment** for advanced PDR with tractional retinal detachment and extensive vitreoretinal fibrosis. - The procedure involves removal of the vitreous gel, fibrovascular membranes, and blood, which relieves traction on the retina and allows for retinal reattachment. - This is the **gold standard treatment** for this condition. *Removal of epiretinal membrane* - **Membrane peeling** (removal of epiretinal and fibrovascular membranes) is an **essential component** of vitrectomy for tractional retinal detachment. - Removing these membranes relieves the mechanical traction causing the retinal detachment, making this a **suitable and necessary** treatment step. - This is performed as part of the comprehensive vitrectomy procedure. *Reattachment of detached or torn retina* - **Retinal reattachment** is the primary **therapeutic goal** for tractional retinal detachment in advanced PDR. - This is achieved through vitrectomy with membrane peeling, often combined with endolaser, fluid-gas exchange, or silicone oil tamponade. - This is clearly a **suitable treatment objective** for this condition.
Question 8: Ocriplasmin is a recombinant protease and it is used to treat:
- A. Submacular bleeding
- B. Diabetic macular edema
- C. Retinal break
- D. Vitreomacular adhesion (VMA) (Correct Answer)
Explanation: ***Vitreomacular adhesion (VMA)*** - **Ocriplasmin** is a *recombinant protease* specifically approved for the treatment of symptomatic **vitreomacular adhesion (VMA)** or *vitreomacular traction (VMT)*. - Its proteolytic activity helps dissolve the proteins at the vitreomacular interface, thereby releasing the traction and potentially preventing progression to other macular pathologies like *macular holes*. *Submacular bleeding* - **Submacular bleeding** is typically managed with anti-VEGF injections, *vitrectomy with subretinal tissue plasminogen activator (tPA)*, or pneumatic displacement, not ocriplasmin. - The goal is to displace or remove blood, which is not the primary mechanism of action for ocriplasmin. *Diabetic macular edema* - **Diabetic macular edema (DME)** is commonly treated with *anti-VEGF agents* (e.g., ranibizumab, aflibercept), corticosteroids, or laser photocoagulation. - DME is characterized by fluid leakage and swelling due to diabetic retinopathy, not vitreomacular adhesion. *Retinal break* - A **retinal break** (tear or hole) is typically managed with *laser photocoagulation* or *cryopexy* to create an adhesion around the break and prevent retinal detachment. - Ocriplasmin does not have a role in the direct treatment or repair of retinal breaks.
Question 9: What is the primary procedure used in retinal detachment surgery?
- A. Encirclage (Correct Answer)
- B. Drainage of subretinal fluid
- C. Removal of vitreous
- D. Vitrectomy
Explanation: ***Encirclage*** - **Encirclage**, or scleral buckling, is the primary surgical technique used to reattach the retina by indenting the sclera to bring the choroid and pigment epithelium closer to the detached retina. - This procedure **closes retinal breaks** and relieves **vitreous traction**, which is often the underlying cause of rhegmatogenous retinal detachment. - It remains the **gold standard** for uncomplicated rhegmatogenous retinal detachments without significant vitreous pathology. *Drainage of subretinal fluid* - While **drainage of subretinal fluid** is often performed as an adjunctive step during retinal detachment surgery, it is not the primary procedure but rather a supplementary maneuver to facilitate retinal reattachment. - Simply draining the fluid without addressing the **retinal break** with encirclage or another sealing technique would lead to fluid reaccumulation and re-detachment. *Removal of vitreous* - **Removal of vitreous** refers to vitrectomy, which is indicated for complex cases with significant vitreous hemorrhage, tractional retinal detachment, or proliferative vitreoretinopathy. - In uncomplicated **rhegmatogenous retinal detachments**, scleral buckling (encirclage) is typically the first-line procedure without requiring vitreous removal. *Vitrectomy* - **Vitrectomy** is a surgical technique involving removal of the vitreous gel, primarily reserved for complex retinal detachments, posterior breaks, or cases with media opacity. - While vitrectomy is increasingly used, **encirclage/scleral buckling** remains the primary and most commonly performed procedure for straightforward retinal detachments, especially with anterior breaks.
Question 10: Consider the following causes of visual loss : 1. Obstruction of the central retinal artery 2. Vitreous and retinal haemorrhage 3. Cataract 4. Retinal detachment Which of the above causes are associated with acute visual loss in a patient?
- A. 1, 3 and 4
- B. 1, 2 and 3
- C. 2, 3 and 4
- D. 1, 2 and 4 (Correct Answer)
Explanation: ***1, 2 and 4*** - **Obstruction of the central retinal artery**, **vitreous and retinal haemorrhage**, and **retinal detachment** all present as sudden, acute vision loss. - **Central retinal artery occlusion** causes complete, sudden, painless monocular vision loss. **Vitreous hemorrhage** is acute, painless, and can present with floaters or red haze. **Retinal detachment** is acute, painless vision loss, often preceded by flashes and floaters, and can present as a "curtain" coming across the vision. *1, 3 and 4* - While **central retinal artery obstruction** and **retinal detachment** cause acute vision loss, **cataracts** typically cause gradual, progressive vision loss over months to years. - Cataracts primarily affect lens clarity, leading to blurry vision, glare, and dull colors rather than an abrupt onset of blindness. *1, 2 and 3* - **Central retinal artery obstruction** and **vitreous/retinal hemorrhage** lead to acute vision loss, but **cataracts** are a cause of *chronic* and *gradual* vision impairment. - The onset and progression of a **cataract** are distinctly different from the sudden nature of acute vision loss conditions. *2, 3 and 4* - **Vitreous and retinal haemorrhage** and **retinal detachment** are causes of acute vision loss, but a **cataract** is not. - The defining characteristic of acute vision loss is its rapid onset, which does not align with the slow development of a cataract.
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