• Topical glaucoma medication with a teal cap?

• Prostaglandin analogues– Xalatan® (latanoprost)

0.005% qd– Travatan®(travoprost)

0.004% qd– Lumigan® (bimatoprost)

0.03% qd

• Mechanism of action: Prostaglandin analogues

• Enhances uveoscleral outflow.

• Topical glaucoma medication with a yellow cap?

• non-selective beta blockers 0.50%– Timoptic® (timolol)– Betagan® (levobunolol)

• β2 selective beta blockers 0.50%– Betoptic S® (betaxolol)

• Topical glaucoma medication with a blue cap?

• non-selective beta blockers 0.25%– Timoptic® (timolol)– Betagan® (levobunolol)

• β2 selective beta blockers 0.25%– Betoptic S® (betaxolol)

• Mechanism of action of beta blockers?

• reduces aqueous production (by blocking beta-2 receptors on nonpigmented ciliary epithelium)

• Topical glaucoma medication with a purple cap?

• α2 adrenergic agonists– Iopidine® (apraclonidine)

• 0.5% tid• 1.0% bid

– Alphagan-P® (brimonidine)• 0.1%• 0.15%• 0.2%• bid or tid

• Mechanism of action for α2 adrenergic agonists

• decreases aqueous production

• increases uveoscleral outflow

• “Both kinds of glaucoma treatment!”

• topical glaucoma medication with a green cap?

• Cholinergic agonists (miotics)– pilocarpine (0.25% --

10%) 2% or 4% most often.

– carbachol– echothiophate

• Mechanism of action for cholinergic agonists

• increases trabecular outflow

• may increas uveoscleral outflow

• Topical glaucoma medication with an orange cap?

• carbonic anhydrase inhibitors (CAIs)– Trusopt® (dorzolamide)

2%– Azopt® (brinzolamide)

1%

• Mechanism of action for carbonic anhydrase inhibitors

• decreases aqueous production

• Glaucoma medications that increase outflow

• Uveoscleral:– prostaglandins– α2 adrenergic agonists

• Trabecular:– cholinergic agonists /

miotics

• Glaucoma medications that reduce aqueous production

• β blockers• α2 adrenergic agonists• carbonic anhydrase

inhibitors

• “Discussion” points for every glaucoma patient:

• “controlling a risk factor (high eye pressure) for glaucoma”

• “in hopes to prevent vision loss”

• “no guarantee that vision loss will not occur”

• “like controlling (blood pressure) a risk factor for heart attack and stroke”

• Glaucoma standard of care

• dilation with retinal biomiscropy

• Goldmann tonometry• visual fields• gonioscopy• pachymetry• photography• (debatable)

OCT/GDx/HRT

• OHTS goals of study • Ocular Hypertension Treatment Study

• Evaluate safety / efficacy of topical glaucoma medications

• to prevent or delay congenital open angle glaucoma (COAG) in patients with high IOP

• identify baseline demographic and clinical factors

• predict which patients will develop COAG

Ocular Hypertension Treatment Study (OHTS)

• OHTS Enrollees • patients with:– high IOP– normal visual fields (VF)– normal discs

• patient randomly assigned to medical treatment or observation

• patient monitored:– VF q 6 months– fundus photos q year– endpoint of COAG:

• VF evidence• disc evidence• or both VF and disc evidence

Ocular Hypertension Treatment Study (OHTS)

• OHTS results • COAG patients:– 55% diagnosed via disc

changes without VF changes

– 20% reduction in IOP decreased incidence of COAG by 50% at 5 years

– black people developed COAG at significantly higher rate

Ocular Hypertension Treatment Study (OHTS)

• OHTS Important risk factors for glacomatous damage in ocular hypertensives

• higher IOP• old age• large C/D• greater pattern

standard deviation• thin central cornea

thickness (CCT)

Ocular Hypertension Treatment Study (OHTS)

• OHTS central corneal thickness (CCT) findings

• patients with CCT less than 555 are 3x more likely to develop POAG

• Much bigger risk factor than:– race– family history– refractive error– general health

• Recommendation: pachymetry as standard part of evaluation of ocular hypertensive patients.

Ocular Hypertension Treatment Study (OHTS)

• OHTS Guidelines • IOP:– 23.75 or below low risk– 23.75 < IOP < 25.75 moderate

risk– above 25.75 high risk

• CCT (pachymetry):– above 588 low risk– 555 < CCT < 588 moderate risk– 555 or below high risk

• vertical C/D– 0.3 or less low risk– 0.3 < C/D < 0.5 moderate risk– 0.5 or above high risk

• In glaucoma, NFL damage precedes…

• field loss and disc changes

• 5 year, 50% “rule” 50% of NFL is lost before a VF will reveal a defect.

• “we are in the business of preventing any vision loss”

• Instruments commonly used to manage patients with glaucoma

• HRT2 – Heidelbert Retinal Tomograph

• Stratus OCT – Optical Coherence Tomography from Zeiss Humphrey

• GDx-VCC nerve fiber analyzer (with variable corneal compensator from Laser Diagnostic Technologies)

• HRT, OCT, GDx factoids • image the optic disc and/or retinal NFL

• each has strengths & weaknesses

• useful for glaucoma suspects moderate glaucoma patients

• NOT helpful for advanced glaucoma patients

• cost: HRT < GDx < OCT

• Optic nerve imaging considerations

• imaging reimbursable at least once a year, HOWEVER, cannot be reimbursed for fundus photos & imaging on same day.

• results need to be used within a larger clinical context!– ONH tissue, VF defects and

imaging should all correlate & “make sense”

• HRT strengths & “considerations”

• The HRT utilizes confocal scanning laser ophthalmoscopy

• Strengths– shows topography of optic nerve– detects patient progression– confirms nerve size– evaluates cupping

• “Considerations”– accuracy depends on drawing

contour line correctly the first time.

– probably not the best for assessing thickness of RNFL

• OCT strengths & “considerations”

• OCT uses optical back scattering of light to compute tomographic images based on amount of incident light reflected by tissue.

• Strengths– accurately measures RNFL thickness– correlates highly with VF loss & disc damage– reproducible– image quality monitored during test– awesome for macular holes, edema CNV

mgmt– reason why less fewer FLANs done at UMSL

• “Considerations”– automatically generated disc contour lies can

be somewhat inaccurate– does not determine progression– difficult to determine how much change is

clinically significant– requires dilated pupil, minimal media opacity

• GDx strengths & “considerations”

• GDx uses a scanning laser polarimeter

• Strengths– measures RNFL– very reliable– portable– can do undilated– media opacities least likely

to interfere

• Considerations– image quality cannot be

measured during test

• GDx NFL analysis • Gives ‘NFI’ number:– 0—30 normal, low

probability of glaucoma– 31—70 glaucoma

suspect– 71—100 high

probability of glaucoma

• The NFI number does NOT indicate severity or progression of glaucoma.