Ocular Surgery Techniques Quiz

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Questions and Answers

What is the primary purpose of rectus muscle recession and resection surgery in the context of nystagmus?

To move the eyes towards the center of the null zone (correct)

To enhance peripheral vision in patients

To correct retinal detachment directly

To completely abolish all symptoms of nystagmus

Which of the following is a complication associated with subretinal fluid drainage for retinal detachment?

Increased visual acuity

Elimination of nystagmus

Retinal perforation (correct)

Improved eye alignment

What is the main indication for performing pars plana vitrectomy (PPV) in retinal detachment surgery?

Presence of small retinal tears

Persistent nystagmus symptoms

Routine ocular examinations

Giant tears or conditions where scleral buckling is unlikely to work (correct)

What materials are commonly used as tamponading agents in retinal detachment surgery?

Expanding gases or silicone oil Signup and view all the answers

What is the mechanism by which scleral buckling helps treat retinal detachment?

It creates an inward indentation to retouch the retina to the underlying layers Signup and view all the answers

What is a notable contraindication for using alpha 2 agonists?

Children under 2 years old Signup and view all the answers

Which side effect is commonly associated with the use of miotics?

Brow ache Signup and view all the answers

How do carbonic anhydrase inhibitors function in the treatment of ocular conditions?

They inhibit aqueous secretion Signup and view all the answers

What is a precaution when prescribing alpha 2 agonists to young patients?

Check for CNS depression Signup and view all the answers

Which example is classified as a carbonic anhydrase inhibitor?

Dorzolamide Signup and view all the answers

What is the primary indication for performing a laser iridotomy?

Primary angle closure glaucoma Signup and view all the answers

Which medication is the first choice for managing elevated intraocular pressure (IOP) after laser iridotomy?

Prostaglandin analogue eye drops Signup and view all the answers

What technique involves delivering laser to the trabecular meshwork to enhance aqueous outflow?

Selective laser trabeculoplasty Signup and view all the answers

Which side effect is associated with the use of prostaglandin analogues?

Iris hyperpigmentation Signup and view all the answers

What is the mechanism of action of beta blockers in glaucoma management?

Decrease aqueous production Signup and view all the answers

What is a major advantage of selective laser trabeculoplasty (SLT) over traditional treatments?

Minimizes ocular side effects Signup and view all the answers

Which statement accurately describes acetazolamide in the context of lowering IOP?

It is used for IOP greater than 50 mmHg intravenously. Signup and view all the answers

What is the typical IOP reduction achieved by prostaglandin analogues?

27-35% Signup and view all the answers

What is the maximum visual acuity (VA) observable for a patient with presenting VA at the level of perception of light (PL)?

6/12 Signup and view all the answers

Which condition requires emergency referral following a post-operative examination?

Suspected endophthalmitis Signup and view all the answers

How does photodynamic therapy (PDT) with verteporfin primarily work?

By damaging proliferating cells Signup and view all the answers

What role do anti-VEGF drugs play in the treatment of wet AMD?

Bind with VEGF to inhibit abnormal blood vessel growth Signup and view all the answers

What is a significant side effect of argon green laser treatment for maculopathy?

Destruction of surrounding healthy tissue Signup and view all the answers

For which patient group does NICE recommend anti-VEGF treatment?

Patients with evidence of progressive wet AMD and no structural foveal damage Signup and view all the answers

What is a potential complication following pan-retinal photocoagulation (PRP) treatment for severe non-proliferative retinopathy?

Scarring and peripheral visual field loss Signup and view all the answers

In which circumstance might a patient with wet AMD be considered for off-label anti-VEGF treatment?

VA better than 6/12 Signup and view all the answers

What is one of the primary complications associated with retinal detachment (RD) surgery?

Transient IOP spikes Signup and view all the answers

Which device is not part of the standard vitrectomy setup?

Laser aspirator Signup and view all the answers

What is the primary purpose of injecting a gas bubble during pneumatic retinopexy?

To seal retinal breaks Signup and view all the answers

Which step is involved in the cataract surgery process of capsulorhexis?

Using a femto laser or cystotome Signup and view all the answers

What complication can arise from posterior capsule rupture (PCR) during cataract surgery?

Increased risk of retinal detachment Signup and view all the answers

Which of the following is a symptom of post-operative endophthalmitis?

Painful red eye Signup and view all the answers

During cataract surgery, what is the purpose of hydrosealing?

To seal the wound without sutures Signup and view all the answers

What type of cataract surgery involves the use of a cryoprobe?

Intracapsular cataract extraction (ICCE) Signup and view all the answers

What is a common post-operative instruction for patients who have undergone cataract surgery?

Instil post-operative drops as specified Signup and view all the answers

Which of the following is NOT a type of cataract surgery mentioned?

Laser-assisted cataract surgery (LACS) Signup and view all the answers

Study Notes

Nystagmus

Surgery on all four recti muscles can be used to center the null zone
Face turn to the right, null zone to left
Surgery moves BE's in the direction of CHP to centre the null zone
RLR 8mm resection, RMR 5mm recession, LMR 6mm resection, LLR 7mm recession
May improve vision but may not abolish CHP
Effect may not last
Most patients will not reach driving standard

Subretinal Fluid Drainage

Drainage of fluid via the sclera for deep or longstanding SRF
Not done frequently due to complications
Complications include retinal perforation, incarceration in the entry site

RD Surgery - Pars Plana Vitrectomy

When: Giant tears, very large breaks, or PVR (where scleral buckling unlikely to work)
Cut and aspirate vitreous
Infusion of saline to maintain the vitreous cavity pressure and volume
Tamponading agents: expanding gases or silicone oil
Complications: Raised IOP, cataracts, band keratopathy

RD Surgery - Scleral Buckling

Silicone sutured onto the sclera, creating an inwards indentation
Closes RD by apposing RPE to sensory retina
Complications; Transient IOP spikes & diplopia, CMO, buckle extrusion/intrusion/infection

RD Surgery - Vitrectomy and Retinopexy

Vitrectomy: 3 ports - infusion cannula, vitreous cutter, and fibreoptic light probe
Remove the central vitreous gel and posterior hyaloid face
Pneumatic retinopexy for small breaks
Inject a gas bubble
Use laser/cryo to seal breaks

Cataract Surgery - Phacoemulsification

Anaesthesia, povidone-iodine 5% or chlorhexidine instillation and eyelid cleaning
Draping and speculum insertion
Creation of 1-2 side ports and the main corneal incision
Viscoelastic into the AC
Capsulorhexis: femto laser, cystotome, forceps
Hydrodissection: insert fluid under capsulorhexis to separate lens from capsule
Divide and conquer/phaco chop
Removal of lens cortex: vacuum carefully peels away from capsule and aspirated
IOL insertion
Wound sealing: hydrosealing, stepped approach
Prophylactic Abx intracamerally/subconjunctivally
Femtosecond lasers: more precise with slightly improved refractive outcomes, but costly, difficult to learn, time-consuming

Other Types of Cataract Surgery

Extracapsular cataract extraction (ECCE): large anterior capsulotomy with large limbal incision
Intracapsular cataract extraction (ICCE): cryoprobe removes entire lens and capsule
Manual small-incision cataract surgery (MSICS) - used for high volume clinics in developing countries

Cataract Surgery - Intra-Operative Complications

Damage to the iris or cornea
Corneal epithelial abrasion, endothelial damage, Descemet's tear, iris damage
Damage to the capsule - posterior capsule rupture (PCR)
Loss of all or part of the cataract or the implant into the back of the eye
Bleed (suprachoroidal haemorrhage) - ruptured posterior ciliary artery
Endophthalmitis

Cataract Surgery - Post Op Review

Instil all post-op drops as specified (Abx and steroids)
Avoid: rubbing/touching eye, dusty/dirty environments, no water or soap in the eye, no swimming, no bending for heavy objects, no eye makeup
Can resume light exercise and everyday activities within 2-3/7
Mild discomfort is normal
May get diplopia initially
Is vision what they expect it to be?
Unexplained reduced vision?
Was there a guarded prognosis?
Do they need listing for the second eye?
Symptomatic cataract?
VA \6/12?

Cataract Surgery - Post Operative Endophthalmitis

Severe inflammation that can lead to total loss of vision
Symptoms: painful red eye and significant loss of vision
Signs: lid oedema and chemosis, significant conj hyperaemia, corneal haze, AC activity, vitritis
Differentials: retained lens material, vitreous haem, severe p/o uveitis
Management: sample aqueous and vitreous for culture, IV + systemic Abx, topical and systemic steroids, pars plana vitrectomy
Prognosis: depends on VA at presentation
If PL 1/3 may achieve up to 6/12, if better than PL then up to 2/3 may achieve this

How Soon to Refer Post-Op Complications

Emergency: suspected endophthalmitis
Urgent: retinal detachment/retinal tear, wound closure problems, marked or persistent mild/moderate iritis, IOP>28mmHg, unexpected IOL displacement +/- refractive surprise, corneal oedema, cystoid macular oedema, severe diabetic retinopathy, drop allergy
Routine: significant symptomatic PCO, patient not happy with vision/refractive outcome/comfort

Photodynamic Therapy (PDT)

PDT with verteporfin has largely been replaced by anti VEGF
PDT may also be used for chronic central serous chorioretinopathy
Intravenous injection of verteporfin (visudyne)
Verteporfin preferentially taken up by the CNV membrane, not the retina, hence no retinal damage
Drug is activated by low powered laser causing damage to proliferating cells and seals/regresses leaking vessels

Anti-VEGF

Vascular endothelial growth factor (VEGF) is a protein that triggers the formation of new blood vessels
Anti VEGF drugs bind with VEGF to prevent the trigger for abnormal blood vessel growth and leakage
Anti VEGF drugs are administered via intravitreal injection
NICE recommends for patients with: evidence of progressive wet AMD, VA between 6/12 and 6/96, no structural damage to the fovea
Refer patients with suspected wet AMD regardless of their level of vision
Patients with VA better than 6/12 or worse than 6/96 may be considered for treatment off license in certain clinical circumstances
Most patients are suitable for anti VEGF ~ 90%

Maculopathy

Argon green laser energy absorbed by and destroys micro-aneurysms
Closes leakage site
Encourages exudates absorption & oedema resolution
May destroy surrounding area
Poor response shown with ischaemic maculopathy

Non-proliferative

Prevent progression to R3
Laser Pan-Retinal Photocoagulation (PRP) - scatter pattern
Reduce O2 demand of retina by tissue destruction, inhibits NV growth
Regression
Scarring & peripheral visual field loss
Tritan colour vision defect

Laser Iridotomy

Treatment of primary angle closure glaucoma (or secondary angle closure with pupil block)
Laser used to create a small hole in the iris
Patient should lie down
Acetazolamide 500mg (IV if IOP >50mmHg, orally if IOP\ 24mmHg)

### Laser Trabeculoplasty

Delivery of laser to the trabecular meshwork in order to increase aqueous outflow
Examples: SLT, Argon laser trabeculoplasty, Micro pulse laser trabeculoplasty
Usage: Primary and secondary open angle glaucoma, ocular hypertension

Selective Laser Trabeculoplasty

First line treatment for Primary Open Angle Glaucoma and Ocular Hypertension
Low energy light targeting melanin rich cells in the aqueous chamber
This results in an immune response whereby white blood cells clear the affected cells and rebuild the trabecular meshwork
Benefits: Reduced ocular and systemic side effects, no tissue damage, reduced need for medication

Prostaglandin Analogues

Increases uveoscleral outflow.
Examples: Latanoprost, Travoprost, Bimatoprost, Tafluprost
Side effects: Skin (reversible) & iris (irreversible) hyperpigmentation
Excessive eyelash growth
Cystoid Macular Oedema
Conjunctival hyperaemia
Avoid in pregnancy

Beta Blockers

Decrease Aqueous production
Examples: Timolol, Betaxolol, Carteolol, Metripranolol
Side effects: Ocular: allergy, punctate corneal erosions, reduced aqueous secretion, Decreased corneal sensitivity
Systemic: Bradycardia, Arrhythmia, heart failure, Bronchospasm, Syncope, Nocturnal hypotension, Headache and depression
Contraindications: Asthma, COPD, bradycardia, heart failure, Normal tension glaucoma

Alpha 2 Agonists

Decreases aqueous production and increases u veo-scleral outflow
Examples: Brimonidine, Apraclonidine
Contraindications: Children under 2 years old, accompanying oral monoamine oxidase inhibitor antidepressants
Note: As these drugs cross the blood-brain barrier and thus caution should be taken in young children who have central nervous system depression and hypotension

Carbonic Anhydrase Inhibitors

Inhibit aqueous secretion
Examples: Dorzolamide, Brinzolamide
Side effects: Blurred vision, induced myopia
Contraindications: sulphonamide allergy, renal impairment, take caution with individuals with corneal endothelial dysfunction

Miotics

Contraction of the sphincter pupillae pulls the peripheral iris away from the trabecular meshwork thus opening the anterior chamber angle
Contract the ciliary muscle - increasing aqueous outflow through the trabecular meshwork
Example: Pilocarpine
Side effects: brow ache, miosis, myopic shift, increase in cataract symptoms, confusion, bradycardia, bronchospasm, and gastrointestinal symptoms
Systemic side effects are rare

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Description

Test your knowledge on various ocular surgical techniques such as nystagmus treatment, subretinal fluid drainage, and retinal detachment surgery. This quiz covers essential information including procedures, indications, and potential complications. Ideal for medical students and professionals in ophthalmology.