Ron Melton, OD, FAAO
Randall Thomas, OD, MPH, FAAO www.eyeupdate.com
st
Medellin, Columbia
August 14-16, 2015

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Population studies suggest over half of all glaucoma patients have not been diagnosed
From the Baltimore Eye Study: One-half of all people who were found to have glaucoma had seen an eye doctor within the past year and were unaware they had glaucoma!
“Despite all the progress being made in the field, it is sobering that ophthalmologists fail to diagnose more than 50% of cases of glaucoma.” (Quigley,
Ophthalmology Times)

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• Suspicious ONH cupping
Elevated or increasing IOP
Subnormal central corneal thickness (CCT)
Advancing age (particularly after 50)
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African or Hispanic origin
- onset earlier (about 10 years), damage more severe, treatment less successful
Positive family history (age at Dx?)
Diurnal fluctuation ?
High myopia

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• OPP = diastolic BP – IOP
Theory: OPP <50mmHg is a risk factor for glaucoma, and glaucoma progression
Examples: DBP of 65 and an IOP of 15
DBP of 85 and an IOP of 35
• These two patients may be at equal risk because they have same theorized OPP of 50mmHg
• Take home message: Begin to check blood pressures on your glaucoma and glaucoma suspect patients, especially those with lower IOPs.
Reference: Quaid, P et al, IOVS, Jan 2013

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• OPP: IOP minus the diastolic blood pressure
“Ocular perfusion pressure: may be the single biggest risk factor for glaucoma onset and progression”
Reference: Liebmann JM. Optometric Glaucoma Society, Boston,
October 2011.

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“The driving force for ocular blood flow is the ocular perfusion pressure (OPP), defined as the ocular artery pressure minus the IOP.”
“Large cross-sectional prevalence studies in different populations found a significant association between low diastolic OPP and the prevalence of OAG.”
“The greater incidence of progression in patients with lower blood pressure, seen mainly in patients with lower IOP, suggests a vascular risk factor for progression independent of
IOP.”
“Low blood pressure . . . may be the most important vascular risk factor for glaucoma progression.”
Reference: AJO. May 2010

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Risk for progression of ocular hypertension to POAG can be assessed
- Age, IOP, vertical C/D ratio, CCT
CCT should be measured in all patients with ocular hypertension and all glaucoma suspects
Patients at high risk should be treated
Therapy should be selected based on efficacy, tolerability, and likelihood of patient compliance

• “In the end, the physician is stuck with the persistent problem of whom to treat and whom to watch.”
• “It probably still makes sense that young patients with lots of high risk factors should receive prophylaxis, while elderly patients with few risk factors should not. The endless symposia and debates on how to best manage patients with ocular hypertension will probably continue unabated.”
Reference: Sommer A. Editorial. Treatment of Ocular Hypertension.
Archives of Ophthalmology. March, 2010.

• “In summary, the second phase of OHTS allows us to draw some important conclusions about the management of patients with OHT. Early medical treatment decreases the cumulative incidence of
POAG. The absolute effect is greatest in high-risk individuals. Conversely, there is little absolute benefit of early treatment in individuals with OHT at low risk of developing POAG.”
Reference: Klass M et al. “Delaying Treatment of Ocular
Hypertension.” Archives of Ophthalmology. March, 2010.

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CCT has become “standard-of-care” inthe POAG (or suspect) work-up
Thinner corneas are a strong risk factor for POAG because true IOP is actually higher than the measured
IOP.
Some patients with measured ocular hypertension may simply have a thicker CCT, thus reducing POAG risk because the true IOP is actually less than the measured
IOP
“CCT is the most heritable aspect of ocular structure
(more than refraction, axial length, or optic disc size), suggesting that it is under exquisite genetic control.”
(Ophthalmology, Nov. 2007)

• “Thinner CCT may be a significant, independent risk factor for open-angle glaucoma among persons with ocular hypertension.”
• “It is unclear whether the impact of CCT as a risk factor for glaucoma is mediated largely through its role in determining measured IOP, or whether the thickness of the cornea is a surrogate for greater susceptibility of the eye to damage.”
Reference: AJO, May, 2006

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This clinical evaluation builds upon a careful family history, personal medical history, current health status, and medication(s)
Best corrected vision
Document pupil size and reactivity
Careful slit lamp biomicroscopy noting A/C depth, any iris abnormalities such as pigment dispersion, retroillumination defects, pseudo exfoliation, corneal guttata, etc.
Applanation tonometry, noting time
Pachymetry to determine CCT

“The advantages of rebound tonometry include portability, lack of dependence on slit lamp mounting or even an external electrical source (battery powered), no need for topical anesthetic, ease of use, suitability for use by nonmedically trained personnel, and toleration by young children and non-cooperative adults. These characteristics make it quite useful in screening situations. In my practice, this is our go to instrument for children as young as 3 years, for the intellectually challenged adults, and those with blepharospasm.”
Reference: R. Stamper, MD, Optometry and Vision Science. January
2011

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Baseline gonioscopy (4-mirror preferred) looking for
PAS, angle recession, angle pigmentation, and the anatomic patterns of the angle anatomy
Thorough BIO to r/o any peripheral pathology
Stereoscopic evaluation of the optic nerve heads
(60D, 78D, or Hruby lens); glaucoma detected most often through dilated pupils
Baseline static threshold visual fields
Image analyzer of optic nerve head (GDX-
VCC/OCT)
Optic disc photographic documentation

• A most wonderful website exists to help teach superb gonioscopic anatomy and technique
• Please seek and study: www.gonioscopy.org

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Cup depth is critical - Stereopsis!
Are cup walls steep or sloping?
Note rim translucency and vertical elongation of the cup
Is the cup concentric with the disc, or is the cup displaced?
Is the neuroretinal rim thinned more at certain clock hours than others? Especially look for any accentuated erosion of the inferotemporal or superotemporal regions.
Is the disc generally pink, yellowish, or pale?

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Helpful diagnostic observation in ONH evaluation
Normal neuroretinal rim anatomy follows the ISN’T rule
- Inferior rim should be thickest
- Superior rim is slightly less thick
- Nasal rim is slightly less thick
- Temporal rim should be the thinnest
Most ONH’s are round or slightly vertically oval
ISN’T rule may not hold if ONH horizontally oval

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Bergtson (25 yrs ago)
Normal small discs have small cups
Normal large discs have large cups.
Average disc diameter 1.5 mm
Small
Disc Diameter
1.0-1.3mm
Medium 1.4-1.7mm
Large 1.8-2.0mm
Mean C/D
.35
.45
.55
Upper Limit
.55
.65
.75
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Implications for glaucoma diagnosis and management
A high ratio may not be pathologic
C/D’s for large discs change by a smaller amount
C/D changes caused by glaucoma occur more slowly in large discs than in small discs (baseline photos large discs especially important
C/D asymmetry is not always pathological

• There is poor agreement between slit lamp ophthalmoscopy, HRT, and OCT in classifying disk size as small, average, or large.
• Jonas proposed that in routine practice, the clinician conduct “a quick, crude estimate of whether the disk in question is average-sized (medium), smaller-thanaverage, or larger-thanaverage.”
Reference: AJO, September, 2006, pp. 375-379

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Highly specific for glaucoma
Commonly inferotemporal in POAG
Commonly superotemporal in NTG
Prevalence higher in NTG (20-35%)
Disc hemorrhages may precede a VF defect or a change in nerve head
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• Ominous sign in glaucoma patients
Associated with aspirin use and diabetes
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(Ophthalmology 09/04)
“Among glaucomatous eyes receiving treatment, those with a larger baseline MD and older age had a faster rate of VF loss after a DH developed.”
“There is no association between CCT and the later development of DH.”
“Recurrence of DH during follow-up was not associated with a fast rate of VF loss in this study.”
(Ophthalmology, January 2010)

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Program Strategies
Perspectives on Perimetry
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Visual Field Interpretation
Foundational guidelines
Catch trials
Grey scale
Total and Pattern deviation
Glaucoma hemifield test
Global indices
Summary
Plaquenil Visual Field Testing

• Once thought rare, optic disc hemorrhages occur in most glaucoma patients.
• It has been proposed that IOP fluctuations represent a key risk factor for glaucoma progression, however, there is no clear evidence to support this concept.
• Another myth is that selective perimetric testing
(such as SWAP or FTD) can detect VF loss before standard white-on-white perimetry.
Reference: International Glaucoma Review of the
World Glaucoma Association, Vol. 10, 2008

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A combined cerebral assessment of:
Pattern Deviation probability plots as compared to
Total Deviation probability plots
Pattern Standard Deviation probability values
• These probability plots give the greatest VF data guidance to the functional status of the patient’s optic nerves
• Remember: ALWAYS CORRELATE THE CLINICAL
FINDINGS WITH THE VISUAL FIELD STUDIES!

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GDX-VCC, OCT-3, HRT, RTA, etc.
Can be helpful in early diagnosis
Limited value in advanced glaucoma
Excellent for detection of progression
A COMPONENT of the glaucoma evaluation
Not a “litmus test” for glaucoma

These socalled “objective” nerve fiber layer scanning devices are only relatively objective compared to highly subjective perimetry. Looking at this next series of GDx scans very nicely demonstrates this clinical truth.

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“Evidence indicates that RNFL and optic disc assessment by imaging technologies may not provide adequate sensitivity to follow-up patients who manifest severe glaucomatous change. In this situation, visual field testing losses are still the best method to quantify the effect of the disease and monitor its progression.”
More succinctly: There is “an inverse relationship between disease severity and the ability to detect change with imaging devices.”
Reference: Archives of Ophthalmology, September 2012

• Regarding optic disc photos, “the agreement for assessment of progressive optic disc changes is poor even among glaucoma specialists.”
• RNFL is mostly ganglion cell axons, whereas neuroretinal rim tissues contain nonneural structures
• Because rate of change within these two tissues may vary with the stage of disease, interpretation of progression should be evaluated on an individual basis
• “It is plausible that detection of progression with OCT RNFL thickness may not be as effective as visual field measurement in moderate and advanced glaucoma.”
Oph. August 2011

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Establish a target IOP below which optic nerve damage is unlikely to occur
Maintain an IOP at or below this target level with appropriate therapy
Monitor VF's and ONH appearance to refine the adequacy of the target IOP
Optimally balance the benefits of therapy with any side effects
Educate and engage patients in the management of their disease

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“Patients with normal optic disc and visual field could tolerate an IOP of 30 mmHg for many years without need of treatment.”
“What it comes down to is . . . treat young patients who are in the high-risk group, and it is worth watching the elderly in a low-risk group. The problem remains what to do for those in the middle.”
Reference: A Sommer / Johns Hopkins Univ. Ophthalmology Times.
January 2011.
Melton-Thomas: All glaucoma doctors struggle with the decision of whom to treat, and when. Remember: medical care is an art, and equally well-trained doctors commonly differ in clinical decision-making.

• Use of a “risk calculator”, and lack of glaucoma specialty training were associated with physicians being more likely to treat ocular hypertension
• 2 / 58 glaucoma specialists and 4 / 118 ophthalmologists reported treating all patients with an IOP >21 mmHg
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Most critical factors: IOP, C/D ratio, and CCT (both groups)
Rational estimation of “risk of conversion” to OAG is essential for proper clinical decision-making
• Treatment by default or faulty decision-making remains a healthcare crisis in glaucoma patient care management
Reference: AJO, October, 2011

“Despite recent breakthroughs in our knowledge of risk of progression, we still are making educated guesses.
At all but the highest pressures, not all patients will progress. Some patients may have non-pressure dependent optic neuropathies that are beyond our current understanding and treatment capabilities.
Around half of patients with normal tension glaucoma will not progress even without treatment.”
Reference: Werner M. Ophthalmology Web. March 12, 2010.

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Most controlled glaucoma patients are seen every 3 to 4 months for monitoring of the IOP and ONH status
Visual Fields and/or a scan are done as frequently as necessary, and at least once yearly
A dilated stereoscopic view of the optic nerve should be performed at least yearly, however, a quick look should be done at each visit.
If control is felt inadequate, more aggressive followup is in order until adequate control of the patient is achieved

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Prostaglandin Analogs
Beta-Adrenergic Blockers
Prostaglandin / Beta-Blocker combinations
Adrenergic Agonists
Adrenergic Agonist / Beta-Blocker combination
Carbonic Anhydrase Inhibitors (CAI’s)
CAI / Beta-Blocker combination
Pilocarpine derivatives
Epinephrine derivatives
Laser Trabeculoplasty
Surgical Trabeculoplasty

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• Latanoprost (Xalatan and generic) 0.005%
Travoprost (Travatan Z) 0.004%
Bimatoprost (Lumigan) 0.01%
Tafluprost (Zioptan) 0.0015%

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• Pharmacology: prostaglandin analog
Mechanism: enhances uveoscleral outflow
Dosage: once daily, usually in the evening
Effectiveness: 30% reduction in IOP
Potential side effects: Iris darkening, hypertrichosis,
CME, iritis, HSK activation, migraine headache, inflammatory bowel disease (IBS)
Xalatan 0.005% by Pfizer (and generic), Travatan
(Z) 0.004% by Alcon, Lumigan 0.01% by Allergan, and Zioptan 0.0015% by Merck

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FDA approved February 2012
First “preservative-free” prostaglandin
Reduces IOP similarly to the other prostaglandins
Dosage: once daily, preferably in the evening
Most common side-effect – conjunctival hyperemia
Available in unit dose containers
Marketed as Zioptan 0.0015% ophthalmic solution by Merck

The Efficacy and Safety of Once-Daily Versus
Once-Weekly Latanoprost Treatment for
Increased Intraocular Pressure
“Latanoprost treatment for ocular hypertension or early glaucoma once-weekly was as effective as once-daily after 3 months of follow-up, and there were fewer, and only minor, side effects with this protocol.”
Reference: S. Kurtz, MD and G. Shemesh, MD. Journal of Ocular
Pharmacology and Therapeutics, November 2004

• Time to onset: 3 to 15 months
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Time to resolution following discontinuation: 3-9 months
“Reversibility of prostaglandin-induced periocular hyperpigmentation is in contrast to the irreversible or very slow reversible nature of prostaglandin-induced iris hyperpigmentation.”
• Mechanistic explanation: dermal melanocytes are continent relative to melanin granules, whereas iris melanocytes are incontinent
• Switching to another prostaglandin may or may not evoke a lessened expression
Reference: Ophthalmology, November 2006

• A more newly recognized side effect of prostaglandin therapy
• Periorbital fat atrophy gives rise to marked deepening of the superior lid sulcus, which can result in ptosis and enophthalmos
• Beyond the obvious cosmetic concerns, such altered lid/orbital anatomy can make applanation tonometry quite challenging
• Probably expressed more in middle-aged patients than in older patients
• Tends to be at least partially reversible over a few months.
Advanced Ocular Care. July-August 2011.

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Timolol (Timoptic and Timoptic XE / Betimol) 0.25% and 0.5%; (Istalol) 0.5% *
Levobunolol (Betagan) 0.25% and 0.5% *
Metipranolol (Optipranolol) 0.3%
Carteolol (Ocupress) 1.0%
Betaxolol (Betoptic-S 0.25%)
* Have longer half-lives than other beta-blockers

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• Decrease aqueous production
Reduces IOP .25%; no response 15%
R/O asthma
Recommend monocular trial with lowest concentration once daily
Possible diminished effect if used with systemic beta-blockers
No advantage to gel-forming solution

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• Brimonidine
Apraclonidine
Dipivefrin
Epinephrine

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Alpha-2 adrenergic agonist; tid FDA approval
Acts by reducing aqueous production with some enhancement of uveoscleral outflow
Reduces IOP similar to timolol 0.5% bid
Side effects: fatigue and dry mouth most common side effects; uveitis reported; may reduce systolic BP 10 mmHg
Less tachyphylaxis or allergy development than the other alpha-2 agonists
Neuro-protective potential unknown
Alphagan (0.2%) by Allergan, and generic
Alphagan P (0.15%) by Allergan and generic, and Alphagan P (0.1%) by Allergan

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• Combination of 0.2% brimonidine and 0.5% timolol
With ANY combination drug, always try one of the component drugs as monotherapy, and only use the combination product if or when the monotherapy drug comes close, but does not achieve target IOP
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Remember, most all drugs have a non-response rate of about
10%, so there is a 20% chance that one of the components of any combination drug is not performing
“The IOP lowering effect, when administered twice daily, has been found to be slightly less than that seen with the concomitant use of 0.5% timolol bid and 0.2% brimonidine tid.”
Ocular Surgery News, Nov. 15, 2007

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If using timolol and not quite to target IOP, then trying Combigan would be rational
If using brimonidine and not quite to target IOP, then rational to try Combigan
If a prostaglandin does not reach target IOP, then try a once daily beta-blocker like timolol. If this two drop therapy approaches, but does not achieve target
IOP, then trying a combination drug is rational
Marketed as Combigan by Allergan in 5, 10, and 15 ml opaque white bottles, preserved with BAK .005%

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• Dorzolamide 2% sol. and Brinzolamide 1% susp.
Mechanism: decreases aqueous humor secretion
Reduces IOP approximately 15%
FDA dosage: tid, practical dosage bid
Contraindications: Allergy to sulfa and/or history of blood dyscrasias
Side effects: minimal; some burning, bitter taste, rare allergic reaction
Most all patients controlled with oral acetazolamide were successfully controlled with a topical CAI
Azopt 1% susp-Alcon; Trusopt 2% sol-Merck

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Both components decrease IOP by reducing aqueous humor secretion
Because of the CAI, must be used bid, which results in excessive beta-blocker therapy
Contraindications: patients with asthma, heart disease, or allergy to sulfa drugs
Ocular side effects: burning/stinging and perversion in taste
Marketed as Cosopt by Merck bottle and PF and generic

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Combination drug without a beta blocker where both ingredient drugs are dosed the same (b.i.d.)
Combines 1% brinzolamide (Azopt ophthalmic suspension) with 0.2% brimonidine
Offers a wide range of treatment possibilities due to its strong efficacy and ability to decrease elevated
IOP by 21- 35%
Marketed by Alcon under the brand name Simbrinza

1st Tier: Prostaglandin q d or timolol q am
2nd Tier: Topical CAI or brimonidine
3rd Tier: Combigan. Cosopt. or Simbrinza
4th Tier: Pilocarpine
Oral CAI (preferably methazolamide)

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Approved 12-96 for seizure disorders
Unapproved: Migraine HA, weight loss, depression, bipolar disorder
Mechanism of action is unknown
Because of a topiramate-associated risk for oral clefts, the FDA has now designated topiramate as a pregnancy category D drug.
Numerous reported cases of acute, bilateral, simultaneous angleclosure glaucoma
Onset usually within first 2 weeks of therapy
Most common presenting symptom: blurred vision
Exact mechanism of increased IOP is unknown
Tx: Stat consult with prescribing physician to begin to reduce topiramate dosage; then aqueous suppressants, oral CAI, cycloplegia (retracts ciliary body) - no miotics
IOP normalizes in 1-4 days, no laser treatment indicated

• Uses: anticonvulsant, migraine prevention, bipolar disorder, obesity, OCD, IIH, neuropathic pain, essential tremor, post-herpetic neuralgia, and other esoteric uses.
Topiramate is a sulfa derivative (like CAI’s)
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Idiosyncratic ciliochoroidal effusion is the most common ocular side effect, and most always results in a myopic shift with or without increased IOP
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This rare event usually occurs within 2 weeks of initiation (or doubling) of dosing
First described in 2001 – 70% are female
• Tx: D/C the medicine; use (PRN) beta-blocker, brimonidine, or, in refractory case, oral prednisone or IV methylprednisolone. Also, instill cycloplegic agent, and do not use pilocarpine.
Reference: Clinical Ophthalmology. January 2012

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New drug for weight loss patients who are overweight or obese and also have at least one weight-related condition such as high blood pressure, diabetes or high cholesterol.
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Combination of two older drugs
Phentermine (appetite suppressant)
Topiramate (feeling of satiation)
Lesser dosages of each component drug tend to act synergistically
On average, patients lose about 10% of their body weight over one year
Marketed by Vivus Inc (Mountain View, California)
FDA approval July 17, 2012