Clinicians check IOP every 2 to 4 months in well-controlled glaucoma patients

Issue: April 2004

Every 3 months

Alan G. Kabat, OD, FAAO: Assuming that the patient has been properly diagnosed, appropriate medications to lower IOP have been used and the treated IOP is acceptable with regard to the nerves and visual fields, I will typically ask patients to return every 3 months. Quarterly IOP measurement is, for most optometric physicians, considered to be the standard of care. Of course, if there is a significant deviation from the target IOP, and particularly if compliance is an issue, I would recommend more frequent visits. Similarly, if patients have maintained a long history of good control and are of relatively low risk for progression, I may have them return every 4 months.

Ideally, I like to get good, reliable visual fields every 6 months on well-controlled patients. Of course, that doesn’t always happen in clinical practice. Patients sometimes have a “bad day,” requiring that fields be repeated on a consecutive visit due to poor reliability or a new defect that was not previously noted. New field defects in the absence of IOP fluctuation or disc changes should always be confirmed a week or so later before altering the treatment regimen; often, they will “disappear” as mysteriously as they appeared.

In a well-controlled patient, I generally do not expect to see much visible change in the nerve head, though I do recommend performing dilated funduscopy at least every 6 months. I prefer to obtain stereo disc photos upon diagnosis and then once yearly thereafter for documentation.

Some practitioners regularly use devices such as the HRT II (Heidelberg Engineering, Vista, Calif.), GDx VCC (Laser Diagnostic Technologies, San Diego) or OCT 3 (Carl Zeiss Meditec, Dublin, Calif.) to image and monitor the optic nerve. I typically employ these only when the diagnosis is unclear or if patients are incapable of producing reliable fields. While these newer techniques may yield additional information about disc topography or nerve fiber layer thickness, they should not supercede the basic clinical tests upon which so much of our research and experience in glaucoma management is based.

Alan G. Kabat, OD, FAAO, is associate professor and director of residency programs at Nova Southeastern University, College of Optometry. He can be reached at 3200 South University Dr., Ft. Lauderdale, FL 33328; (954) 262-1470; fax: (954) 262-1818, e-mail: kabat@nova.edu. Dr. Kabat has no direct financial interest in the products he mentions, nor is he a paid consultant for the companies mentioned.

Every 3 to 4 months

Kristen Brown, OD, FAAO: For well-controlled glaucoma patients, I check IOPs every 3 to 4 months, depending on the severity of the glaucoma (e.g., extent of field loss, extent of nerve fiber layer loss, cup-to-disc ratio, pachymetry, family history and systemic medical history). I image the optic nerve with fundus photos annually. I image the optic nerve fiber layer with a GDx VCC nerve fiber layer analyzer every 6 months and perform visual fields every 6 to 12 months.

I am performing visual fields less often (but at least annually) and I am relying more on nerve fiber layer analysis. I find nerve fiber layer analysis more reliable than visual fields because it is an objective test, it is faster and it is easier to perform than visual fields. Patients tolerate nerve fiber analysis better than visual fields. I rarely have to repeat the nerve fiber layer analysis; whereas, I often have to repeat visual fields due to poor reliability. Lastly, I rely more on nerve fiber layer analysis when I suspect a patient has early glaucoma because I am less likely to see visual field defects at this time.

I do not rely solely on nerve fiber layer analysis when evaluating glaucoma. However, it is one of my more powerful tools in assessing early glaucoma and subtle progression of glaucoma. I expect that I will always include visual fields in my assessment of glaucoma and glaucoma suspects; however, with earlier detection, earlier treatment and better drops for treating glaucoma, I hope to see fewer patients with significant visual field loss from glaucoma over time.

Kristen Brown, OD, FAAO, is an adjunct clinical professor of optometry, New England Eye Institute, New England College of Optometry, and an attending optometrist, Dimock Community Health Center. She can be reached at 55 Dimock St., Roxbury, MA 02119; (617) 442-8800, ext. 1232; fax: (617) 427-4566; e-mail: kbrown1@dimock.org. Dr. Brown has no direct financial interest in any of the products she mentions, nor is she a paid consultant for any companies she mentions.

Every 4 months

Ian Ben Gaddie, OD, FAAO: The two major challenges in glaucoma care are determining who has the disease and then determining the management strategy for each patient. There is a fine line between prudent follow-up and overkill with regard to frequency of visits and special testing. Once I have established that a specific treatment has stabilized the pressure and the damage, I usually will follow patients every 4 months for IOP checks. Visual field testing and laser imaging are performed annually, unless optic nerve changes or subjective visual field deterioration occur.

To establish significant change in a visual field, the results must be repeated and verified. In these instances, more frequent visual field testing may be indicated. I rarely bill nerve imaging more than once a year, unless a significant clinical finding warrants more frequency. Several imaging technologies exist, each with their own advantages. For example, the GDx VCC is excellent for imaging the retinal nerve fiber and tracking change over time, but it gives you limited data on the optic nerve parameters.

A second technology — such as the OCT 3, HRT II and RTA (Talia Technologies, Tampa, Fla.) — that provides three-dimensional optic nerve parameters and precise optic nerve and rim dimensions could supply the practitioner with additional information and tracking capabilities. If some of these technologies are proven to be diagnostically synergistic, this may be a reasonable argument for multiple reimbursements.

Ian Ben Gaddie, OD, FAAO, can be reached at Gaddie Eye Centers, 7635 Shelbyville Rd., Ste. 101, Louisville, KY 40222; (502) 423-8500; fax: (502) 339-0571; e-mail: ibgaddie@bellsouth.net. Dr. Gaddie has no direct financial interest in any of the products he mentions, nor is he a paid consultant for any companies he mentions.

Depends on the degree of damage

Lee S. Peplinski, OD, FAAO: What seems to be a simple question is actually multidimensional, as is often the case with glaucoma. To me, well controlled means that we’ve “righted the ship.” But this does not take into account how much damage the patient’s ship has already obtained from the glaucoma storm. We may barely be “keepin’ ‘er afloat” if the damage is already heavy. In these cases, patients still need closer attention. Remember the old adage: “Don’t be the last person to see a patient before he or she goes blind.”

What do I mean by closer attention? I’ll probably see these patients every 2 to 3 months for a pressure check, view or image the optic nerve several times in a year and get fields at about 6-month intervals (provided they are helpful). Keep in mind that patients with advanced damage may need different field parameters (such as a 10-2) if the fields are very constricted. Also, imaging on a totally cupped nerve is probably not helpful in your decision making. If the test does not add to your assessment, don’t do it.

For cases with milder glaucoma, where they’ve only “sustained a few hits,” less frequent follow-up may be in order. In the early stages with reasonable IOPs, glaucoma damage will take a while to be detectable as change with our current testing. IOP checks every 4 months, with a dilated optic nerve exam and visual fields annually will probably be enough. Certainly, some patients will fall between these two extremes and will need to be followed appropriately.

The longer you see that things remain stable, the more confidence you may gain that this patient won’t change. It’s a factor of when you came on board. I have several patients who can go 6 months between checks, and for some with mild damage who have had surgical therapy, it may be even longer.

Unfortunately, as with anything in our profession, insurance plays into the picture. There is a difference between tests you would like to have and tests you need to have. Nerve fiber analysis may be desired, but if the patient can’t afford it and he or she doesn’t have insurance, I won’t run the test as long as I can make sound decisions based on the big three: optic nerve assessment, visual field and IOP. Some insurance companies also limit how often certain tests, such as photos, may be performed.

Always remember that it is better to bring the patient back or repeat certain tests more frequently until you feel the ship has been righted and until he or she is under good control.

Lee S. Peplinski, OD, FAAO, is in private practice in Louisville, Ky. He can be reached at Bennett & Bloom Eye Centers, 4010 Dupont Circle, Ste. 380, Louisville, KY 40207; (502) 895-0040; fax: (502) 361-4488; e-mail: DrP@eyecenters.com. Dr. Peplinski has no direct financial interest in any of the products he mentions, nor is he a paid consultant for any companies he mentions.