Article Date: 1/1/2014

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MEDICAL MODEL
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Improve Your Glaucoma Efforts

Find and retain glaucoma patients rather than referring them

ROBERT E. PROUTY, O.D., F.A.A.O., PARKER, COLO.

With a continued improvement in diagnostic technology that allows early diagnosis and refined monitoring of patient status, now is the perfect time to embrace the management of glaucoma. (See “Glaucoma Workup Figures,” page 29.)

All 50 U.S. states statutorily enable O.D.s to manage glaucoma to varying degrees. In addition, glaucoma patients are frequently loyal to their O.D.s, as once you identify and properly manage the disease, they entrust their sustained visual care to you beyond traditional refractive needs.

Here, I explain how you can assess and retain these patients.

Be the early bird.

The vast majority of glaucoma is asymptomatic until the moderate to late stages of the disease. Therefore, conduct a thorough exam that includes the following:

Family history. Nearly 25% of glaucoma patients report a family history.1 Therefore, ask patients whether they have a sibling with glaucoma, as this raises their risk of primary open angle glaucoma (POAG) nearly four fold.2 Also, keep in mind that having a first-degree relative with POAG raises the prevalence 4% to 16%.3

Ethnicity and age. Realize that people of African descent (particularly Afro-Caribbeans) show a nearly five-time greater prevalence of glaucoma, a higher risk of blindness and a tendency to be diagnosed before age 50 vs. other populations.1

Also, consider that Hispanic-Americans younger than age 50 develop POAG at a rate similar to Caucasian Americans (about 5%), but the incidence increases dramatically with age (60 years old) and eventually exceeds African-American rates after age 70. In addition, be aware that pseudo-exfoliative glaucoma and pigmentary glaucoma are more common in Caucasians with a cluster of the former noted in northern Europeans/Scandinavians.

Finally, understand that age and ethnicity are important in the consideration of angle closure glaucoma, as age-related cataract development, hyperopia and Asian ethnicity are factors.1

Look beyond IOP.

Glaucoma diagnosis involves more than just an elevated IOP. Also, the reliable continuous monitoring of IOP is yet to be refined, as corneal thickness, corneal biomechanics, diurnal fluctuations and nocturnal sleeping position affect measurement results. Therefore, employ these assessment techniques in addition to an IOP assessment:

Gonioscopy. While it is tempting to assess the angle as open or closed or estimate the angle using the slit lamp Van Herick technique alone, you must visualize the angle and structures of the trabecular meshwork to fully understand the mechanics involved in a case of glaucoma. Outflow resistance is a critical element in understanding the condition and its proper management. Visualization through gonioscopy allows you to rule out angle closure, angle recession, plateau iris or secondary angle block as a cause of elevated IOP.

Optic nerve head (ONH) and nerve fiber layer (NFL) assessment. Nearly 50% of the NFL may be lost prior to the presence of repeatable visual field (VF) deficits.4,5 Therefore, carefully examine the ONH rim, cup depth, asymmetry, flame hemorrhages and vessel patterns for abnormalities, such as rim thinning and increased depth or size greater than expected.6 Also, measure the NFL status, as NFL declines from baseline or population norms usually precede ONH changes and VF deficits.4,5

The latest OCTs have enhanced algorithms to better apply to glaucoma and ONH or NFL evaluation, including macular ganglion cell complex assessment.

VF evaluation. Test-taking technology has reduced test time, patient fatigue and the learning effect variability (SITA and TOP testing strategies). Interpretation has been aided with statistical packages that analyze data relative to age-matched normal values (total deviation), scan for patterns of loss and assess the subject’s intra-test reliability and symmetry (pattern deviation, Glaucoma Hemifield Test and Bebie curve). Also, this technology makes it possible to project VF loss rates when assessing management success through time via analysis algorithms, such as VF indexing.7

Provide treatment education.

Regardless of which medication class you prescribe, educate patients on dosing, how the drug works and side effects. The reason: Such education provides incentive to comply with the prescribed drug. Also, it is valuable to ask the patient to always bring their bottles of drops to each follow-up appointment so as to confirm the medication, monitor use based on the remaining fill of the bottle and stimulate any discussion on challenges to the patient’s sustained success in use.

The goal with these drug classes is to decrease visual decline so patients suffer little visual affects during their lifetime. This means frequent follow-ups to monitor status, refining the medical management of their IOP and ensuring they sustain useful vision and visual field.

Here are the management options, which are predicated on the type of glaucoma (open angle, narrow/closed angle and secondary glaucomas):

Prostaglandin analogues. These include travoprost (Travatan, Alcon), bimatoprost (Lumigan, Allergan), latanoprost (Xalatan, Pfizer) and tafluprost (Zioptan, Merck). Bimatoprost and latanoprost are preserved with benzalkonium chloride (BAK), Travoprost is preserved with “Sofzia,” while Tafluprost is non-preserved.

When prescribing this drug class, inform patients to use the drops once daily. Also, warn the patient they may experience burning and stinging upon installation, eyelash growth and darkened eye color.8–11 Chronic, red-irritated eyes may have BAK sensitivity. This can affect your secondary drug choice and patient compliance.

GLAUCOMA WORKUP FIGURES
YEAR ONE Code Charge# Totals
Routine eye care visit 92004 $150.74 $150.74
Diagnostic w/up (1-2 weeks) 99213 $72.76 $72.76
ONH Photo 92250 $79.26 $79.26
Gonioscopy 92020 $27.81 $27.81
Pachymeter 76514-26 $9.97 $9.97
76514 TC $5.35 $4.28*
$194.28
Testing follow up 2 (1-2 weeks) 99213 $72.76 $72.76
VF (24-2) 92083 $65.13 $65.13
OCT 92133-26 $28.55 $28.55
OCT 92133 TC $16.14 $12.91*
$179.35
IOP Follow up (1-2 weeks) 99212 $43.82 $43.82
Follow up (4-6 mos) 99213 $72.76 $72.76
VF (24-2) 92083 $65.13 $65.13
OCT 92133-26 $28.55 $28.55
OCT 92133 TC $16.14 $12.91*
$179.35
Annual Total $747.54
YEAR TWO Code Charge Totals
Follow up (typically twice per year) 99213 $72.76 $72.76
VF (24-2) 92083 $65.13 $65.13
OCT 92133-26 $28.55 $28.55
OCT 92133 TC $16.14 $12.91*
$179.35
x2
Annual Total $358.70
Grand Total $1,106.24

# = Example charges are based on 2014 Medicare Par rates in Colorado
* = Same day subsequent diagnostic testing with 20% reduction of technical component

Carbonic anhydrase inhibitors (CAIs). Explain to patients this drug class decreases aqueous production, thereby lowering IOP.

The two topical medications in this class, dorzolamide (Trusopt, Merck) and brinzolamide (Azopt, Alcon), are FDA approved at t.i.d. Notify the patient of possible stinging and irritation due to pH differences.

The oral forms acetazolamide (Diamox, Duramed Pharmaceuticals) and methazolamide (Neptazane, Fera Pharmaceuticals) are powerful and can cause extremity tingling, metallic mouth taste, electrolyte depletion and are considered sulfonamide derivatives. It appears that the antibiotic sulfonamides are different than the topical CAIs, so a more applicable concern may be the overall allergy/atopy nature of the patient. Sulfonamide allergy should be considered if severe (hives, throat swelling), but the general atopy patient has a greater risk of adverse reaction than the sulfonamide allergic patient. Topical use of CAIs appear safe in the oral antibiotic sulfonamide sensitive patient with normal monitoring for adverse reactions.12

Alpha-adrenergic agents. Brimonidine (Alphagan, Allergan) is FDA-approved t.i.d. Bromonidine is available in generic and branded forms of 0.1%, 0.15% and 0.2%. Tell patients to monitor eyelid swelling, eye itch and chronic eye redness if they become sensitive. Also, check the lower lid palpebral conjunctiva for follicle formation during follow-ups, which is another clinical indicator of developing/developed sensitivity.

Beta-blocker agents. These come in various generic forms and have side effects that are difficult to uncover — you must feel comfortable asking about depression, impotence, breathing/asthma effects in the history review once the patient has been using them for an extended period (typically four to six months). Also, question patients about these side effects at every follow-up. Beta-blockers are commonly used q.d. or b.i.d. based on their instillation vehicle (gel based vs. solutions) and are usually well tolerated on the eye.

Combination agents. Cosopt (timolol and dorzolamide combination, Merck) has shown good efficacy with b.i.d. dosing, but warn patients of possible stinging upon instillation and BAK chronic irritation possibilities (Cosopt PF is now preservative free). Another beta-blocker combination, Combigan (timolol and bromonidine 0.2%, Allergan), should be used b.i.d. Common adverse reactions include allergic inflammation of the eye, abnormally large lymph follicles in the mucous membrane lining the inner surface of the eyelid and the conjunctiva, eye redness, severe eye itching, burning and stinging.

Brinzolamide/brimonidine tartrate ophthalmic suspension 1%/0.2% (Simbrinza, Alcon) a combination agent of a topical CAI and an alpha-adrenergic, negates the previously mentioned beta-blockers’ side-effect profile and shows good efficacy. It is used t.i.d.

Historical agents. Adrenergics (epinephrine and dipivefrine (Propine, Allergan), anticholinesterases (echothiophate and physostigmine) and cholinergics (carbachol (Mio-stat, Alcon; Carbastat, Novartis Opthalmics) and pilocarpine (Isopto Carpine, Alcon; Pilopine HS, Alcon) are also used. Pilocarpine has sustained its use clinically (typically q.i.d.). Warn patients of brow ache, which is commonly noted in early use but usually fades with time. Also, due to pupillary miosis, explain that vision can be affected (particularly in with a cataract) and scotopic vision can decline. The drug is commonly started at 1/2% to 1% and increased to 2% to 4% to reduce the brow ache induction until IOP control is achieved. Uveitis is a contraindication for these agents.

Emergent laser procedures and oral CAIs have largely replaced hyperosmotic agents, as they provide limited short-term IOP reduction in acute angle-closure attacks.

If none of the aforementioned drugs are effective, refer the patient for surgery.

Reach your goals.

The addition of (or access to) a full threshold VF, a new generation OCT and a pachymeter is usually all that is needed for glaucoma care. Managing glaucoma in your office should be as common place as managing the other myriad of ocular disorders you already oversee. OM

References are available in the online version of this article at optometricmanagement@gmail.com.

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Dr. Prouty specializes in glaucoma and anterior segment consultation at Specialty Eye Care. E-mail him at RProuty@DrMyii.com, or send comments to optometricmanagement@gmail.com.



Optometric Management, Volume: 49 , Issue: January 2014, page(s): 28 29 67