to chop or to drop Flashcards
medication first advantage
! Drugs are safer than surgery- ! Less complications
! Less discomfort
! Drug effects can reversed or is short acting
! Less expensive in the short run
! Multiple drugs can be combined to achieve successful reduction in IOP
! Better quality of life when compared to surgery first (Lichter et al., Ophthalmology 2001)
medications first disadvantages
! May be more expensive in the long run ! Multiple drugs
! Compliance, adherence and persistence issues
! Chronic drug uses and its effect on future surgical outcomes?
! Preservatives effect?
! Inflammation leading to failure of future procedures*
! Increased chances of cataract formation
surgery first advantages
! If successful and large drop in IOP may be obtained ! No issues related to patient compliance, adherence
and persistence
! Good in situations where obtaining continuous supply of medications is a problem
! May be cheaper long term
surgery first disadvantages
! Outcomes may be variable
! Long term may loose efficacy
! May still require additional topical medications
! Complications may be dire
! Comfort and quality of life may be lower
! Chances of cataract formation is greater than topical medications
! Age- young vs. older individuals
race and management options
! Race – white versus individuals with greater pigment
! Individuals with greater pigment- greater risk of pos- operative scarring*
! Medications –first choice
age and management options
! Younger individuals
! Accelerated wound healing systems
! Thick fleshy periocular tissues heals rapidly
! Thus older individuals better suited for surgical options
what does it mean if right eye got surgery and got endophthalmitis; now left eye got it, what is it called
idk
current practice patterns
! Unacceptable high pressures will inevitably destroy optic nerve tissue
! Safe levels of IOP by any means warranted ! If these don’t work or not sufficient
! drugs like – prostaglandins
! reduction in inflow – beta blockers
! Maximal medical therapy ! Consider surgery
what iop can lead to glaucoma and lose significant vision?
40 mm Hg
! Stage of disease “ Visual field status
! Stage of nerve damage “ Rim tissue remaining
! Type of glaucoma
! Open angle glaucoma – medical first makes sense ! Secondary glaucoma
! Congenital glaucoma treated differently ! Complete angle closure
! Adherence, compliance, persistence issues
! Effect of medications and future outcomes of surgery
! Stage of disease “ Visual field status
! Stage of nerve damage “ Rim tissue remaining
! Type of glaucoma
! Open angle glaucoma – medical first makes sense ! Secondary glaucoma
! Congenital glaucoma treated differently ! Complete angle closure
! Adherence, compliance, persistence issues
! Effect of medications and future outcomes of surgery


if anyone has advanced glaucoma, where do we want the pressures?
low teens; or else will have continuous damage
target pressure
! A theoretical value below which visual field and ONH appear stable (not deteriorating).
! Calculated from highest recorded IOP. ! Conventionally 20-30% decrease in IOP. ! 40% or more if severe glaucoma
indication for medication
! Early glaucoma ! Compliant patient ! Target IOP achieved ! Works with life style/ physical ability ! Not too many medications (ocular)
indication for surgery
! Moderate to advanced glaucoma
! Chances of serious loss of vision
! Unable to take medications- various reasons
! Unable to achieve and maintain target IOP
argon laser trabeculoplasty (ALT) theory
! Enhances aqueous outflow
! How does it cause increase outflow
! Exact mechanism unknown
! Mechanical theory
“ Mechanical tightening of trabecular meshwork
“ Opens adjacent untreated spaces !
Laser induced cellular changes
“ Macrophages migrate to the location “ Clears trabecular debri
which laser therapy do we use to lower oag?
SLT
alt indications
! Open angle
! Require decrease in IOP
! Both POAG and secondary like pseudoexfoliation or pigmentary
poor candidates for alt
! Angle recession, uveitic glacuoma, aphakia, high IOP (35 or
greater), high episcleral venous pressure ! Very young individuals
! Previous 360 degree ALT
preoperative considerations of alt
! Depends on status of disease
! Continue IOP lowering medications (if on it)
! If moderate loss or damage
! Preoperative 1% apraclonidine or hyperosmotic agent
! Best performed undilated
! Does not require pupil constriction either
procedure of alt
! Anesthetic and goniolens with coupling fluid ! Clear view is a must
! Ideal lens Ritch lens (good view, optics most suitable and least collateral damage)
! Recommended spot size is 50 micro meter and 0.1 second duration
! Power 0.5 W to1.0 W
! Ideally tissue should blanch or small bubble should form
! Anesthetic and goniolens with coupling fluid ! Clear view is a must
! Ideal lens Ritch lens (good view, optics most suitable and least collateral damage)
! Recommended spot size is 50 micro meter and 0.1 second duration
! Power 0.5 W to1.0 W
! Ideally tissue should blanch or small bubble should form
post operative management
! Remain in office for 1 hour at least
! Monitor IOP
! 1% apraclonidine immediately after procedure
! Topical CAI or pilocarpine may be considered or oral hyperosmotic agents
! Steroid use for 4 days
! Prednisolone acetate 1% 4 times a day for 4 days
! Continue IOP lowering medications if already on it
! Follow-up schedule 1,4 and 8 weeks (approx 2 months)
outcome of alt
! If IOP still high
! Consider doing other 180 degree if option (4 weeks later)
summary of alt
! Laser burns to trabecular meshwork
! Enhances aqueous flow and thus lowers IOP ! Usually an adjunct therapy
! Treatment benefit seen 4-6 weeks
! 180 degrees at a time, 360 can be done ! Retreatment not effective
results of alt
! POAG success rate 75-80%
! Average reduction in IOP reduction is 30%
! 50% still controlled after 5 years
! Failure if occurred usually first year
! NTG success rate 50-70%
! Absolute reduction in pressure not as good as POAG
! Pseudoexfoliation glaucoma ! Excellent results
! Not as good in other secondary glaucoma ! Does not work in pediatric glaucoma
whats failure of surgery?
pressures climb back up; this happens within first year or so
why is ntg not as successful as poag?
iop is not high to begin with
why does pseudoexfoliation glaucoma have good success rate?
lens material, flaky dandruff material, pigment can get out easier
alt vs. slt
Unlike ALT SLT does not scar
! Autopsy specimens – confirm no coagulative damage
after SLT
! Ultrastructural measurements show
! Crackling of intracytoplasmic pigment granules ! Disruption of trabecular endothelial cells
! In-vitro studies pulsed laser
“ longer than 1 microsecond –non selective damage of pigmented
cells
“ 10 nanosecond to
moa of slt
! 5-8 fold increase in monocytes and macrophages in TM
! after treatment with SLT
! Hypothesis
! Injury via laser causes releasing of chemoattractant
! This in turn recruits monocytes that are transformed into macrophages
! Macrophages clear pigment granules and exit via Schlemm’s canal
preoperative considerations
! Alpha 2 agonists preoperative (Brimonidine or Apraclonidine)
! Helps reduce post-operative spikes
! Untreated eyes- timolol may also work ! Topical anesthetic before procedure
slt procedure
! Frequency doubled Q-switched Nd:YAG laser ! 532 nm ! Pulse 3 nanosecond ! Spot size 400 micro meter ! Beam focused over pigmented TM ! Standard therapy 50-100 adjacent non-overlapping spots over 180-360 degrees ! Power 0.8mJ (0.2 to 1.7mJ) ! Heavily pigmented eyes – lower power ! Endpoint- tiny “champagne” bubbles
how does power of slt compare to alt?
lower
*not that in heavily pigment eyes, u use even lower power
SLT
! Selectively targets melanin pigment of TM
! More safe compared to ALT (because lower power) ! Equally effective as ALT
! Can be repeated if first attempt is not effective
post operative considerations
! Anti-inflammatory medications –post SLT
prophylaxis
! NSAID or steroids
! Does not give added benefit in lowering IOP
! No robust evidence in suggesting use or not to use anti-inflammatory agents post SLT
indication for slt
! Acute primary angle closure
! One to two days after attack
! Once eye is settled and edema is cleared
! Fellow eye of acute primary angle closure ! 50% chance of angle closure
! Chronic angle closure ! Narrow or occuludable angle
contraindication for slt
! Significant edema ! Unable to visualize iris ! Thick iris ! Dilated pupil. bunched up iris ! High risk of complications ! Significant inflammation
laser iridoplasty
! Procedure to open an appositionally closed angle
! Series of laser burns ! Low power
! Large spot
! Longer duration
! Extreme peripheral iris
! This causes tightening of peripheral iris creates a space between anterior iris surface and trabecularmeshwork
if patient has PI, and it narrows. this can turn into combined mechanism glaucoma. what does this mean?
narrow angle with anatomical structures that dont help;
a version of this is a pt who does not open up significantly after PI is done. this means structures behind iris are pushing iris forward. anatomical reason iris is not opening up?
what do we need to make sure of with PI?
angle is narrow and doesnt open up over time
trabeculectomy
! Creates a fistula that allows aqueous from anterior chamber to subtenons space
! Fistula guarded by scleral flap
! The belb should not be fully vascularized neither
completely avascular
! Mytomycin C (alkylating agent) or other antimetabolites (example 5-flurouracil) prevents scarring and failure
glaucoma implants indications
! Uncontrolled glaucoma
! Poor candidates for tabeculectomy “ Neovascular glaucoma,
“ penetrating keratoplasty or retinal detachments with glaucoma
“ ICE syndromes traumatic glaucoma, previously failed trabeculectomy
