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Controversies in Glaucoma Anthony B. Litwak, OD, FAAO VA Medical Center Baltimore,Maryland Glaucoma is an Enigmatic Disease Risk factors may or may not be present Who do we treat, who do we observe? Early glaucoma diagnosis can be difficult Determining progression can be arduous Some patients gets worse, some don’t No two glaucoma patients are exactly the same Is One Ever Enough? The IOP in Glaucoma Fluctuates More Than You Think Diurnal Changes More Common in Glaucoma (Greater than 6 mm Hg) IOP Fluctuation is Not Simply Based on Diurnal Variation IOP Can Vary From Day to Day You Can Never Rule Out an IOP Spike Get Three Baseline IOP Readings Before Starting Glaucoma Treatment Helps Uncover Diurnal Fluctuation Mix Two Morning Readings With One Afternoon Imperative for Setting Target Pressures Emphasize the Highest Reading when Setting the Target Pressure Allows for Determining the Effectiveness of Medications Consider Diurnal Curve for NTG Patients Baltimore Eye Survey Over 5000 individuals received complete eye exams in a community in east Baltimore Glaucoma was diagnosed based on the appearance of the optic nerve and visual fields The initial IOP was < 22 mmHG in 55% of newly diagnosed, untreated glaucoma patients If you took two IOP readings, 24% had both readings < 22 mm HG If you took multiple IOP readings, 16% had all IOP readings < 22 mm HG Diurnal IOP Range and Disease Progression CCT – IOP fix or Something More? CCT and Ocular Hypertension What trumps a risk factor for glaucoma? Show Me The Nerve!!! Glaucoma is a disease of the optic nerve, specifically the ganglion cell axon Elevated IOP, AA race, + family history, older age, thinner CCT increase the RISK of developing glaucoma Visual field loss is the end result Glaucoma is damage to the optic nerve Compare Neuro-Retinal Rim Tissue Between Superior and Inferior Does Size Really Matter? Is there a C/D ratio that defines glaucoma? Do You Think This Nerve Has Glaucoma? A Big Cup Does Not Necessarily Mean Glaucoma There is No Demarcation Line Separating a Physiological Cup From a Glaucomatous Cup Physiological Cup Size Is Directly Related to Overall Disc Size Large Discs Will Have Large Physiologic Cups Small Discs Will Have Small Physiologic Cups Physiologic Disc and Cup Size Is Genetically Determined Physiologic Cup of .7 Or Greater Occurs in 2% of Normals A Small Disc With a Medium Size Cup Should Be As Suspicious As a Large Cup in a Medium Size Disc How to Evaluate Disc Size Use a 60 D Lens at the Slit Lamp Make a Thin Vertical Beam Adjust Beam Height Read Disc Diameter off Scale on Slit Lamp Vertical Disc Diameter > 2.2 mm Is a Large Disc Vertical Disc Diameter < 1.8 mm Is a Small Disc Expected Physiologic Cup Size Based on Measured Vertical Disc Diameter Using a 60 Diopter Lens At The Slit Lamp Can you have a normal VF and still have glaucoma? Patterns of Diffuse NFL Loss Focal NFL Defects Interpreting VF’s – Back to Basics Does elevated IOP and an abnormal VF always equal glaucoma? Don’t Always Believe the Visual Field A Significant Number of Patients are Poor Visual Field Testers Poor Reliability - Look at Reliability Indicators, But Don’t Always Believe Them Learning Curves - Repeat the Visual Field When the Field Does Not Match the Optic Nerve Always Correlate the Visual Field with the Optic Nerve How much attention should we pay to reliability indexes? Is Blue Yellow Ready for Prime Time? SITATM SWAP for the HFA SITA SWAP Technology The SITA SWAP Printout Glaucoma Drugs – Who’s on First? Prostaglandin Agonists Xalatan Travatan Lumigan XLT Study Hyperemia Grading Scale Mean Hyperemia Score When Should We Use Prostaglandins? 1st Line POAG Pseudophakia with Glaucoma Uveitic Glaucoma Acute Angle Closure Glaucoma Chronic Narrow Angle Closure Glaucoma Pigmentary Glaucoma Pseudo-exfoliative Glaucoma Neovascular Glaucoma Traumatic/Angle Recession Glaucoma Normal Tension Glaucoma Beta Blockers Bad Drugs or Bad Rap? Beta-Blockers Most Cost Effective Glaucoma Medication Tolerated Very Well By The Majority of Patients Well Studied and Long Track Record (1979) Screen Patients for Potential Contraindications Uniocular Trials Standard of Care or Substandard? Cross over effect of adrenergic agents Assumes that diurnal variation is constant between the two eyes Compare a series of IOP readings pre-medication and a series post-medication Make sure you have established the baseline diurnal variation Judging Progression Which Way is Best? Tailor the Treatment to the Individual Patient The Most Difficult Aspect of Glaucoma Management is Determining Progression Compare Serial Optic Nerve/NFL Photographs Compare Serial GDx, OCT, HRT Compare Serial Visual Fields 55% Progressed by Disc Photos and 35% Progressed by VF’s in OHTS Study 89% Progressed on VFs and 11% Progressed by Optic Nerve Phototgraphs in NTG Study It is Difficult to Differentiate Long Term Fluctuation (can vary by 10db or greater) in the Visual Field From Glaucoma Progression Which Patients Should We Worry About? Patient who presents with severe damage, based on optic nerve, NFL and VF Patient who is young Patient who is African American Patient who is an IOP spiker Patient with a thinner cornea Patient with family member (sibling) blind from glaucoma Patient blind in one eye from glaucoma Patient who is non-compliant Patient who shows progression of glaucoma despite glaucoma treatment AGIS 7 Sustained IOP below 18 mm Hg: Positive Correlation with Stability of Visual Field HRT: Progression Analysis Overview Variability Issues with Standard Perimetry GPA Overview GPA Single Field Analysis Printout Lasers Wars – ALT vs SLT? ALT ALT (argon laser trabeculoplasty) was initially utilized in patients who failed medical therapy The Glaucoma Laser Trial (GLT) established efficacy of ALT in lowering IOP as 1st line treatment in newly diagnosed primary open-angle glaucoma patients ALT should not be repeated to the same area of trabecular meshwork (thermal damage) Selective Laser Trabeculoplasty Uses Q-switched Nd:YAG Laser 532 Nm Wavelength Short Pulse Duration (3 Nanoseconds) 400 um Spot Size 50 Spots Over 180 Degrees Of Tm 0.6-1.2 MJ Selective Laser Trabeculoplasty Selectively Targets Pigmented Trabecular Cells Without Thermal Damage To Adjacent Cells (Biological Effect) Less “traumatic” than ALT May be able to repeat treatment with SLT Selective Laser Trabeculoplasty Clinical Results Mean IOP Reduction 6 mm Hg (25% Reduction) from pre-treatment baseline of 24 mm Hg 24% Showed Post-op IOP Spike Of 5 mm Hg Or Greater International studies show IOP reductions of 22%-28% with 36-49 weeks follow-up In a prospective, randomized clinical trial, SLT and ALT were shown to have a similar effect on IOP reduction 70% of patients [uncontrolled OAG on Max. Rx and prior failed laser trabeculoplasty (PFLT)] respond with > 3 mm Hg drop in IOP How often can you repeat SLT? Who Are Good SLT Candidates? Patients with poor compliance; good for flattening diurnal curve Can be considered first line treatment in POAG SLT targets pigmented cells- probably works better in patients with more pigment in TM Works well in pigmentary and pseudoexfoliation Patients with very heavy pigmentation have difficulty - absorption is so good that you have to turn power down due to discomfort Can use after successful ALT and may avoid the need for filtering surgery Who are Poor SLT Candidates? Inflammatory or uveitic glaucoma Congenital glaucoma/ICE syndromes/NVG and angle recession Narrow angle glaucoma or patients in whom it is difficult to visualize TM 400 um spot size – this is large spot size; so need good/deep angle to fit this spot size Might try pilo prior to tx to see if can visualize more of angle When Do We Filter? Filtering surgery has significantly greater potential complications than medications and laser I rarely recommend filtering surgery to achieve an initial target pressure Risk/Benefit Ratio Patient shows documented progression despite maximal tolerated medical and laser therapy What are the benefits of filtering surgery Achieve low target pressures Control IOP spikes Less reliance on patient’s taking their medications What are the drawbacks of filtering surgery In skilled surgeon hands, it is still only 80% successful IOP is often higher in a failed filter than before the surgery Accelerate cataract formation More local foreign body sensation Risk of catastrophic complications Normal Tension Glaucoma Does It Really Exist? NTG Clinical Pearls Common form of glaucoma (10-20%) Diagnosed by careful inspection of the optic nerve and NFL and screening VFs (FDT) Be sure to establish baseline IOP (Diurnal helpful) Check Pachymetry Similar in characteristics to POAG with some slight modifications IOP lowering is beneficial in patients with NTG Avoid non-selective beta blockers Use Prostaglandins, alpha agonists, topical CAI’s, ALT and filtering surgery to achieve a 30% reduction NTG is Not A Diagnosis of Exclusion When do you do additional testing to R/O other etiologies? Evidence of disc pallor Visual field loss respects the vertical midline Greater temporal than nasal visual field loss Visual field loss out of proportion to optic nerve damage Be sure to rule out unreliable visual field tester Over 95% of NTG do not require a neurological massage Should We Abolish the Term “Normal Tension Glaucoma”? We Do Not Fully Understand the Pathophysiology of NTG or High Tension Glaucoma Overlap in Risk Factors, Optic Nerve, NFL and Visual Field Appearance 50% of Glaucoma Patients Will Exhibit an IOP Reading <21 mm Hg Patients may have thinner CCT and have false low IOP readings Basically Treat Patients Similarly Whether They Have NTG or High Tension Glaucoma COMPLIANCE Never Assume That Your Patient is Compliant Reasons For Poor Compliance Poor Patient Education Inconvenience of Instilling Eyedrops Hectic Lifestyle Side Effects of Medications Cost of Medications Develop a Doctor-Patient Bond Starts From Day One Educate Patients About Their Disease Explain Benefits and Side Effects of Medications and Therapy Explain Other Glaucoma Treatment Options Use Dosing Schedule Sheets with Pictures of the Meds Emphasize the Positive Don’t Ignore the Negative Develop the Patient’s Trust
