Setting target IOP vital to glaucoma management

Issue: November 1995

PANAMA CITY BEACH, Fla.— Of all the risk factors for glaucoma--elevated IOP, family history, visual field defects and optic nerve changes--optometrists can manipulate only one: IOP. Thus, setting a target IOP becomes a significant part of glaucoma management, said Anthony B. Litwak, OD, at a symposium here.

mugshot --- Anthony Litwak

Tools that help the optometrist establish an effective target IOP include a baseline IOP reading, gonioscopy and visual field tests, said Litwak, chief of Clinical Eye and Vision Care at Fort Howard VA Medical Center, Baltimore. Litwak spoke on glaucoma diagnosis and management at the 12th Annual Bay Point Anterior Segment Symposium. He offered the following guidelines for glaucoma management:

Make the diagnosis
Set the target pressure
Initiate treatment
Monitor progression
Re-evaluate treatment plan
Maintain medication compliance

No standard IOP

The irony in setting a target IOP, Litwak said, is that there really is no recommended IOP for glaucoma patients. "We can only estimate what we think the IOP should be and then we follow that patient and look for progressive damage to determine if we have set a target pressure that is low enough for that patient."

One way to determine a patient's progress is with serial visual field tests. Patients who show little damage on their visual fields are more likely to stay stable, Litwak said, while progression should dictate a more definitive, aggressive treatment.

"You will probably want to have these patients filtered," he said. This procedure creates an opening through which aqueous fluid passes from the anterior chamber into a sac created beneath the conjunctiva, alleviating pressure within the eye.

To chart a patient's progress or problems, Litwak uses glaucoma flow sheets in his clinic. They provide the optometrist with basic information at a glance, including when pressure readings were taken, when visual fields were performed, type of medication prescribed and if the patient underwent an argon laser trabeculoplasty.

Check non-medicated IOP

Before prescribing glaucoma medication, Litwak recommended that ODs check the IOP several times without medication. This may mean delaying the start of treatment for a week or two in order to get several pressure readings, but these readings will provide a basis for evaluating treatment.

When gathering medical history, the optometrist can determine if any glaucoma medications are contraindicated in the patient. "You do not give beta-blockers to patients with breathing problems or low heart rates," he said. "We start with the lowest concentration of medication and assess the effect of the medications individually."

Litwak also advises against prescribing multiple medications to a glaucoma patient unless there is a need to lower intraocular pressure quickly due to end-stage disease and high pressures.

Finally, Litwak said, optometrists must maintain a healthy doctor-patient relationship with their glaucoma patients because they are patients for life. "If you do not have a good rapport with your patients and they do not understand why they are taking these medications--which have side effects and can be expensive--they may look for another doctor."