Q. What is the long-term efficacy of laser trabeculoplasty and medical treatment in PXFG?

A) They both remain highly effective for decades

B) They both lose efficacy after some years

C) Only medical treatment remains effective

D) Only laser trabeculoplasty remains effective

Answer: B) They both lose efficacy after some years

Explanation: Both laser trabeculoplasty and medical treatment are initially effective for managing PXFG, but they tend to lose efficacy after some years. This underscores the need for ongoing monitoring and potential adjustments in treatment strategy.

πŸ‘οΈ Long-Term Efficacy of Laser Trabeculoplasty and Medical Therapy in Pseudoexfoliative Glaucoma (PXFG)

πŸ“ OVERVIEW

Pseudoexfoliative Glaucoma (PXFG) is a secondary open-angle glaucoma caused by deposition of pseudoexfoliative material in the trabecular meshwork (TM), leading to increased outflow resistance and elevated intraocular pressure (IOP).

PXFG is:

  • More aggressive than Primary Open-Angle Glaucoma (POAG)
  • Associated with higher IOP at diagnosis
  • More likely to be unresponsive to monotherapy
  • Often requires earlier surgical or laser intervention

⚑ SELECTIVE LASER TRABECULOPLASTY (SLT) IN PXFG

πŸ”¬ Mechanism:

  • Selective photothermolysis of pigmented TM cells using 532 nm Nd:YAG laser.
  • Inflammatory response leads to ECM remodeling and increased aqueous outflow.

πŸ“Š Efficacy Data – SLT in PXFG

βœ… 1. Martindale et al. (2020, Journal of Glaucoma)

  • Study: Retrospective cohort; 71 eyes with PXFG
  • Outcome: IOP reduction β‰₯20% achieved in:
    • 73% at 6 months
    • 66% at 12 months
    • 43% at 24 months
  • Median duration of efficacy: 19 months
  • Conclusion: SLT is effective in PXFG but with declining long-term efficacy.

βœ… 2. Realini et al. (2008, Ophthalmology)

  • Study: 5-year follow-up of SLT in PXFG vs POAG
  • Results:
    • Initial IOP reduction: ~30% in both groups
    • Sustained effect longer in PXFG vs POAG
  • Findings:
    • Greater IOP reduction in PXFG due to high baseline IOP
    • Success rate decreased to ~40% by 4–5 years
  • Conclusion: SLT is effective in PXFG but requires repeat treatment or adjunctive therapy.

βœ… 3. Shazly et al. (2011, Canadian Journal of Ophthalmology)

  • Prospective comparative study: PXFG vs POAG
  • Result: Greater IOP lowering in PXFG (31%) than in POAG (25%) at 12 months
  • Conclusion: SLT may be more effective short-term in PXFG due to TM pigmentation.

πŸ” Repeatability

  • SLT is repeatable in PXFG, unlike argon laser trabeculoplasty (ALT).
  • Efficacy of repeat SLT:
    • Second SLT yields lower IOP reduction than the first.
    • May provide additional IOP control for 1–2 years.
  • No cumulative damage to TM with SLT.

πŸ’Š MEDICAL TREATMENT IN PXFG

🚨 Challenges in PXFG:

  • Higher and more fluctuating IOPs than POAG
  • Faster optic nerve damage
  • Worse visual field progression
  • Reduced response to monotherapy due to advanced TM obstruction

πŸ“Š Efficacy Data – Medical Therapy in PXFG

βœ… 1. Konstas et al. (2004, American Journal of Ophthalmology)

  • Study: Comparison of latanoprost vs timolol in PXFG and POAG
  • Results:
    • Latanoprost: ~31% IOP reduction in PXFG
    • Timolol: ~23% IOP reduction
  • Conclusion: Prostaglandin analogues are most effective single agents in PXFG.

βœ… 2. Topouzis et al. (2007, Journal of Glaucoma)

  • Longitudinal comparison of PXFG vs POAG with maximal medical therapy
  • Findings:
    • PXFG required more medications to reach target IOP
    • Faster visual field loss in PXFG despite treatment
  • Conclusion: Medical therapy less effective long-term in PXFG.

βœ… 3. AGIS Study (Advanced Glaucoma Intervention Study)

  • PXFG eyes often needed earlier surgical intervention despite maximum medical therapy.
  • Visual field progression linked to fluctuating IOP, which is common in PXFG.

πŸ’‘ TREATMENT COMPARISON: SLT vs MEDICAL THERAPY IN PXFG

ParameterSLTMedical Therapy
Initial IOP reduction25–30%20–30% (depends on drug class)
Durability12–36 months (variable)Chronic use, but often loses efficacy in PXFG
RepeatabilityYesNot applicable
Response in PXFGOften better than POAG initiallyVariable; monotherapy often insufficient
Side effectsMinimalOcular surface disease, systemic risks
ComplianceHigh (single outpatient session)Often poor in elderly; multidrug regimens
ProgressionMay delay surgeryOften progresses despite 2–3 medications
Cost-effectivenessHigh (esp. in resource-limited settings)Cumulative long-term cost is high

πŸ‘οΈ TREATMENT OF PXF & PXFG

(Names | Dosages | Mechanisms | Indications | Surgery)

πŸ”Ή 1. OVERVIEW

  • PXF (Pseudoexfoliation Syndrome): Early phase, usually without IOP elevation or optic nerve damage.
  • PXFG (Pseudoexfoliative Glaucoma): Later phase with trabecular meshwork obstruction, elevated IOP, and optic nerve damage.

Goals of treatment:

  • Lower intraocular pressure (IOP)
  • Preserve optic nerve function
  • Minimize disease progression
  • Improve long-term visual prognosis

πŸ’Š 2. MEDICAL TREATMENT OPTIONS

PXFG tends to be more resistant to monotherapy than POAG and often requires combination treatment.

βœ… A. Prostaglandin Analogues (First-line agents)

DrugDoseMechanismIOP ↓Notes
Latanoprost 0.005%OD at night↑ Uveoscleral outflow25–33%Well tolerated
Travoprost 0.004%OD at night↑ Uveoscleral outflow25–33%Good for pigmented irises
Bimatoprost 0.01–0.03%OD at night↑ Uveoscleral & TM outflow28–33%Strongest PG analogue
Tafluprost 0.0015%OD at night↑ Uveoscleral outflow25–30%Preservative-free; useful in OSD

πŸ“Œ Notes:

  • Most effective monotherapy
  • Minimal systemic side effects
  • May cause conjunctival hyperemia, eyelash growth, iris pigmentation

βœ… B. Beta-Blockers (Second-line)

DrugDoseMechanismIOP ↓Contraindications
Timolol 0.25–0.5%BID↓ Aqueous production (Ξ²1 & Ξ²2)20–25%Asthma, bradycardia
Betaxolol 0.25%BIDSelective Ξ²1-blocker15–20%Safer for asthmatics, less effective

πŸ“Œ Notes:

  • Combine well with PG analogues
  • Avoid in elderly with cardiac/pulmonary disease

βœ… C. Carbonic Anhydrase Inhibitors (Topical)

DrugDoseMechanismIOP ↓Cautions
Dorzolamide 2%BID–TID↓ Bicarbonate production β†’ ↓ Aqueous production15–20%Sulfa allergy
Brinzolamide 1%BIDSimilar15–20%Better tolerated (less stinging)

πŸ“Œ Notes:

  • Often used in combination drops (e.g., Cosopt = Dorzolamide + Timolol)

βœ… D. Alpha-2 Adrenergic Agonists

DrugDoseMechanismIOP ↓Contraindications
Brimonidine 0.1–0.2%BID–TID↓ Aqueous + ↑ Uveoscleral outflow20–25%Children <2 y/o, depression, MAOIs

πŸ“Œ Notes:

  • Neuroprotective potential
  • Can cause fatigue, dry mouth, allergy

βœ… E. Fixed Combination Therapies

BrandComponentsDose
XalacomLatanoprost + TimololOD
DuoTravTravoprost + TimololOD
CosoptDorzolamide + TimololBID
CombiganBrimonidine + TimololBID
SimbrinzaBrinzolamide + BrimonidineTID

πŸ“Œ Notes:

  • Increase compliance
  • Reduce preservative exposure

βœ… F. Systemic Carbonic Anhydrase Inhibitors (for short-term IOP control)

DrugDoseIndication
Acetazolamide250 mg BID–QIDAcute IOP spikes or pre-op
Methazolamide50–100 mg BIDAlternative with fewer GI side effects

⚑ 3. LASER THERAPY

Selective Laser Trabeculoplasty (SLT)

ParameterDetails
IndicationFirst-line in PXFG or adjunct to drops
MechanismStimulates TM remodeling via cytokine release
Energy0.8–1.1 mJ; 50–100 applications over 360Β°
Effectiveness20–30% IOP reduction
Duration1–3 years; repeatable

πŸ“Œ More effective in PXFG than POAG due to heavy TM pigmentation
πŸ“Œ May delay or reduce need for surgery

πŸ”ͺ 4. SURGICAL OPTIONS

PXFG often progresses to requiring surgery earlier due to poor medication response and IOP fluctuations.

βœ‚οΈ A. Trabeculectomy (with Mitomycin-C)

ParameterDetails
MechanismCreates new fistula for aqueous outflow
IOP ↓30–50%
ComplicationsHypotony, bleb failure, infection, fibrosis
AdjunctMitomycin-C 0.2–0.4 mg/mL to reduce scarring

πŸ“Œ Gold standard for surgical IOP control
πŸ“Œ More inflammation in PXFG; MMC often required

βœ‚οΈ B. Glaucoma Drainage Devices (Tubes)

TypeIndications
Ahmed valve, Baerveldt implantFailed trabeculectomy, scarring, uveitis, neovascular glaucoma

πŸ“Œ More predictable IOP control long-term in complex cases

βœ‚οΈ C. Minimally Invasive Glaucoma Surgery (MIGS)

ProcedureDeviceNotes
iStent injectMicro-bypass into Schlemm’s canalUseful with cataract surgery
Hydrus MicrostentSchlemm’s canal scaffoldCombined with phaco
XEN Gel StentSubconjunctival outflowBridge between MIGS and trab
GATT (ab interno trabeculotomy)No implantSuitable in early PXFG with open angles

πŸ“Œ MIGS appropriate for early-moderate PXFG with cataract

πŸ‘οΈ D. Cataract Surgery Considerations

PXF eyes are at increased risk of intraoperative complications due to:

  • Zonular weakness
  • Poor pupillary dilation
  • Capsular instability

Precautions:

  • Use capsular tension rings (CTR)
  • Iris hooks / Malyugin ring for dilation
  • Close post-op IOP monitoring (risk of spikes)

πŸ”„ 5. FOLLOW-UP & MONITORING

ParameterFrequency
IOP (Goldmann tonometry)Every 3–6 months (more frequent in PXFG)
Visual Fields (Humphrey 24-2 or 10-2)6–12 months
OCT RNFL + Macula6–12 months
Optic Disc EvaluationAnnually or more
GonioscopyAnnually

🧠 Summary Table: PXF & PXFG Treatment Overview

ModalityOptionsMechanismNotes
MedicalPG analogues, BBs, CAIs, Alpha agonists↓ Aqueous, ↑ OutflowOften need 2–3 agents
LaserSLT↑ Trabecular outflowRepeatable, good early option
SurgeryTrab, GDD, MIGSDiversion of aqueousEarlier need in PXFG
SystemicAcetazolamide↓ AqueousFor IOP crises
CataractPhaco + MIGSVision & IOP benefitHigh zonular risk in PXF

ROLE OF SURGERY

  • Due to poor long-term control with meds/SLT, PXFG often requires:
    • Trabeculectomy (with MMC)
    • Tube surgery (if prior failure or high risk)
    • MIGS + phacoemulsification (in early/moderate cases)

πŸ“Œ Summary

Due to rapid progression, closer monitoring and earlier surgical referral are recommended.

SLT:

Effective as first-line or adjunctive therapy in PXFG

Better short-term IOP control than in POAG

Efficacy wanes over time; may need repeat treatment

Medical therapy:

Prostaglandin analogues most effective

Often requires polytherapy

Less effective long-term in PXFG due to mechanical TM blockage

Combination of SLT and medical therapy may defer surgery in many cases.

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