Vision and Ophthalmology Surgical Procedures and Treatments 2 — Questions and Answers
Question 1: Selective laser trabeculoplasty (SLT) reduces IOP by:
- Burning and destroying trabecular tissue
- Selectively targeting pigmented trabecular cells to improve outflow (Correct answer)
- Creating a new drainage pathway
- Reducing aqueous production
Correct answer: Selectively targeting pigmented trabecular cells to improve outflow
SLT uses a 532 nm frequency-doubled Nd:YAG laser to selectively target melanin-containing trabecular cells, triggering a biological response that improves aqueous outflow without coagulative damage.
Question 2: A scleral buckle procedure treats rhegmatogenous retinal detachment by:
- Removing the vitreous
- Indenting the sclera to bring the choroid closer to the detached retina (Correct answer)
- Injecting gas into the vitreous cavity
- Sealing retinal breaks with laser alone
Correct answer: Indenting the sclera to bring the choroid closer to the detached retina
Scleral buckling places a silicone band or sponge around the eye to indent the scleral wall, relieving vitreoretinal traction and approximating the retina to the RPE.
Question 3: Photodynamic therapy (PDT) with verteporfin is used for which condition?
- Glaucoma
- Predominantly classic CNV in wet AMD (Correct answer)
- Nuclear cataracts
- Optic neuritis
Correct answer: Predominantly classic CNV in wet AMD
PDT involves IV verteporfin (photosensitizer) that accumulates in CNV; activation with 689 nm laser causes selective thrombosis of the abnormal vessels.
Question 4: Corneal transplantation (DSAEK/DMEK) selectively replaces which layer of the cornea?
- Epithelium
- Stroma
- Endothelium and Descemet's membrane (Correct answer)
- Bowman's layer
Correct answer: Endothelium and Descemet's membrane
DSAEK (Descemet's Stripping Automated Endothelial Keratoplasty) and DMEK replace only the diseased endothelium and Descemet's membrane, preserving the recipient's stroma.
Question 5: Botulinum toxin injection for strabismus works by:
- Strengthening the antagonist muscle
- Temporarily paralyzing the overacting muscle, allowing the antagonist to stretch it (Correct answer)
- Permanently cutting the overacting muscle
- Adjusting the lens position
Correct answer: Temporarily paralyzing the overacting muscle, allowing the antagonist to stretch it
Botulinum toxin (Botox) injected into an overacting extraocular muscle temporarily paralyzes it, allowing the antagonist to pull the eye toward alignment during the paralysis period.
Question 6: Which surgical procedure is used to treat posterior capsule opacification (PCO) after cataract surgery?
- Repeat phacoemulsification
- Nd:YAG laser posterior capsulotomy (Correct answer)
- Corneal transplant
- Trabeculectomy
Correct answer: Nd:YAG laser posterior capsulotomy
Nd:YAG laser posterior capsulotomy creates an opening in the opacified posterior capsule, immediately restoring vision in a quick outpatient procedure.
Vision and Ophthalmology Surgical Procedures and Treatments 2
Selective laser trabeculoplasty (SLT) reduces IOP by: