Gather the evidence to make case for glaucoma treatment

November 15, 2009

Although heuristic factors will always be a part of the art of ophthalmomology, we are now in an era in which payments for medical treatments are going to be increasingly scrutinized for therapeutic effectiveness.

Sydney, Australia-Although heuristic factors will always be a part of the art of ophthalmology, we are now in an era in which payments for medical treatments are going to be increasingly scrutinized for therapeutic effectiveness. Therefore, ophthalmologists may be well-advised to focus on an evidence-based approach to identifying high-risk glaucoma cases. That's the word from Ivan Goldberg, MBBS, FRANZCO, FRACS, clinical associate professor, University of Sydney and head, glaucoma unit, Sydney Eye Hospital, Australia.

"We must focus on the why, when, what, and how as we try to tailor our treatments to the risk of future disability," Dr. Goldberg said. "We base that on a number of things, such as the stage of the disease when we make our diagnosis and start our treatment, our determination of the risk factors for progression, and an analysis of the patient's overall heath status and life expectancy."

"As practitioners, we must always be asking ourselves, 'Is there damage, structurally or functionally, that can be demonstrated? Is there new damage that demonstrates progression? Is there a change in the patient's general status?' Those are the changes that affect the risk profile," Dr. Goldberg said. An analysis of these factors, in turn, drives the aggressiveness of therapy.

In patients with suspected glaucoma, a high prevalence of the following factors represents those at highest risk of conversion to primary open-angle glaucoma (POAG): ocular hypertension, increasing age, gonioscopic evidence of suspected primary angle closure, pigment dispersion syndrome (even with normal IOP), glaucoma-like discs, and family history of glaucoma.

Conversely, less important factors for the conversion of suspected glaucoma into POAG are steroid use, myopia, peripapillary atrophy, non-insulin-dependent diabetes mellitus, uveitis, and systemic hypertension.

According to Dr. Goldberg, patients with suspected glaucoma may be considered at moderate risk of conversion to POAG if they have these risk factors: a fellow eye with established glaucomatous optic neuropathy (GON); ocular hypertension with multiple risk factors such as thin central corneal tissue, high IOP, and glaucoma-like discs; gene mutations associated with severe GON; recurrent retinal nerve fiber layer hemorrhages; and pseudoexfoliation syndrome.

Patients with suspected glaucoma at high risk of conversion, and patients with POAG at moderate 5-year risk of progression, include those who have mild GON with early visual field loss and high IOP, mild-to-moderate GON with a low pre-treatment IOP, and primary angle closure with elevated IOP and peripheral anterior synechiae. Younger patients with these factors are at particular risk of conversion or progression, Dr. Goldberg said.

At highest risk

Finally, patients with POAG with the highest risk of 5-year progression and visual disability include those who have moderate to advanced GON with visual field loss, along with any of these factors: demonstrated progression over a short period; high IOP; bilateral visual field loss; pigmentary or pseudoexfoliative glaucoma; advanced visual loss or threatened fixation; younger age; secondary glaucoma; and primary angle-closure glaucoma.

Dr. Goldberg said that although control of IOP is important, IOP should not be the sole focus of assessments and therapies.

"Measure pressure in terms of corneal parameters such as central corneal thickness, assess cup-to-disc ratios in terms of disc size, look at pressures treated versus pre-treatment, all the while remembering the patient's general status and looking for other things that may be contributing to the risk of progression or conversion, such as variable volatile blood pressure levels and sleep apnea," Dr. Goldberg concluded.

Ivan Goldberg, MBBS, FRANZCO, FRACS
Phone: +61 (0)2 9231 1833
E-mail: eyegoldberg@gmail.com

Dr. Goldberg is a consultant for and receives research support and lecture fees from Alcon Laboratories; is a consultant for and receives lecture fees from Allergan, Inc., and Pfizer; and receives lecture fees from Ellex Medical Lasers.