glaucoma management
Managing Glaucoma Patients As They Progress
These case reports show how optic nerve head topography is a crucial component in managing glaucoma patients.
BY MIKE HANEN-SMITH, O.D., M.S., Minneapolis, Minn.

Optic nerve head (ONH) topographic analysis can identify glaucomatous and normal discs with a high degree of precision. It can also provide your practice with substantial benefits in managing glaucoma patients and it's a profitable purchase for most eye clinics as well.

With this HRT follow-up report a noncompliant patient recognized red X's as trouble and became compliant.

The latest imaging instruments (Heidelberg Engineering's Retinal Tomograph II [HRT II], Talia Technology's Retinal Thickness Analyzer [RTA], the Carl Zeiss Meditec's Stratus Optical Coherence Tomographer [OCT] and Laser Diagnostic Technologies' GDx) provide powerful tools for detecting the early stages of primary open-angle glaucoma (POAG).

I'll discuss how these instruments benefit us in the management of our glaucoma patients as they progress.

Saving sight

Differentiating a glaucomatous ONH from a normal ONH can prove challenging. Clinicians have little trouble in classifying the appearance of the ONH once they've established POAG, but many patients have ONH images that are less clear.

Most of the newer instruments provide us with a progression analysis for monitoring changes in the images over time. By comparing the data of subsequent scans, the instruments can help us identify the conversion from ocular hypertension to POAG and allow us to make rapid decisions about the appropriateness of diagnosis and treatment.

A rapid, accurate diagnosis is critical. Misdiagnosis can be devastating because uncontrolled glaucoma results in progressive destruction of the ganglion cell axons of the retina with subsequent visual field loss, which is largely irreversible.

If we hope to reduce blindness, then we need a reliable system to help us determine if our treatment plan will maintain the retinal nerve fiber layer (RNFL). ONH topographic analysis satisfies both of these needs.

Seeing the benefits

My clinical practice has used confocal scanning laser tomography (HRT II) for the past three years. The following case studies illustrate how the instrument has become a major asset in decision analysis and a tool to facilitate patient compliance.

Following improvement. I was treating J.S., a 72-year-old white male, for POAG. His initial therapy regimen of betaxolol 0.25% q.a.m. obtained an IOP within my target range of 17 mm Hg. A second HRT six months later showed a change of -0.20 on the normalized parameter value of the Trend Report. (The HRT plots these measurements in a user-friendly graph that you can use to follow the progression of glaucoma under a treatment regimen).

Ophthalmoscopy and binocular retinal evaluation revealed no detectible change in the ONH. I added latanoprost 0.005% q.h.s. to the therapy regimen at that time, which lowered his IOP to 13 mm Hg. The third scan (one year later) revealed a reversal of ONH parameters and is a predictor of clinical stability. Progression Analysis change window shows excavation of the superior cup with early notching at one o'clock. This change window highlights those areas of change from the initial scan and allows for more accurate detection of ONH damage.

Improving compliance. S.B. is a 41-year-old white male receiving treatment for POAG. He was noncompliant until he saw the results of a subsequent HRT scan showing parameter changes. The cup area increased by +0.294mm² (18%) while the rim area decreased by -0.293 mm² (41%). This occurred while "under treatment," which he admitted he wasn't following. An HRT follow-up report (see figure on pg. 67) full of red Xs induced compliance immediately.

Getting reimbursed

Medicare reimbursement policies for retinal tomography include diagnosis and management of early glaucoma. Billing code 92135 has a national Medicare payment rate of $67 per eye and is allowed on an annual basis. Given the diagnostic capabilities and treatment evaluation that the procedure affords, no comprehensive eye clinic should be without some form of ONH evaluative capabilities.

A winning technology

Retinal tomography has improved my capacities in diagnosing and treating glaucoma in my practice, and I believe it will become the standard of care for the detection of ocular hypertension treatment conversion into POAG and for the analysis of therapeutic efficacy in POAG.

References available on request.

Dr. Hanen-Smith received his O.D. from Indiana University in 1975 and his M.S. in physiological optics from Indiana University in 1993. He's been in private practice in Minneapolis since 1976 and has published articles and has lectured in his home state to optometric audiences.