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Top-nine from the Optometric Glaucoma Society Annual Meeting
Anaheim, California, October 20-22, 2008

Murray Fingeret

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1. The Los Angeles Latino Eye Study (LALES) was developed to determine the burden of eye disease as well as the causes of blindness and visual impairment among Latinos. To be eligible, subjects had to self-identify as being Latino/Hispanic and be age 40 years or older. Nearly 5% of the Latinos studied had open-angle glaucoma. This rate increased with age, from about 8% for those in their 60s to 15% in their 70s. The number of Latinos with glaucoma since 2000 is projected to increase 66% by 2010, 184% by 2020 and 280% by 2030. Major factors associated with elevated IOP include higher systolic blood pressure, higher central corneal thickness and diabetes mellitus.¹ Other positively correlated variables included age, female gender, higher diastolic blood pressure, larger body mass index, darker colored irides, and nuclear sclerosis. Some 75% of Latinos who were diagnosed with glaucoma or ocular hypertension were undiagnosed before participating in LALES. Also, subjects who had glaucoma but whose IOP was less than <21mm Hg were three times more likely to be undetected than those who had higher IOP. This finding suggests the need to discount the value to high IOP in screening for and diagnosis of glaucoma. (Rohit Varma, Los Angeles, CA USA)
   ¹ Memarzadeh F, Ying-Lai M, Azen SP, Varma R; Los Angeles Latino Eye Study Group. Associations with intraocular pressure in Latinos: the Los Angeles Latino Eye Study. Am J Ophthalmol 2008 Jul;146(1):69-76.
2. When a series of studies evaluating progression are reviewed, it is common to find an individual getting worse on either structural or functional tests but not both. The question then is whether structural and functional tests are related and why the apparent dissociation. The dissociation does not necessarily imply that structure and function are actually changing at different rates. Reasons for the dissociation include high test-retest variability, learning effect, functional loss occurring unrelated to structural damage (ganglion cell dysfunction, media opacity) and damage is not necessarily synonymous with retinal ganglion cell loss. Other explanations may include different test criterion, different scales (linear-structure vs. logarithmic-function) and different anatomic sampling patterns. One solution may be to design algorithms that combine structure and functional tests. The question then is how to combine tests that use different units in which we do not know how they relate. Combining tests may provide more robust evidence that change has occurred as well as provide better estimates of rate of change. (D.F. Garway-Heath London, UK)
3. Measurement noise in part explains poor agreement between current tests in detecting structural and functional progression. Measurement noise is certainly unrelated: a patient with highly variable images will not necessarily give highly variable field results and vice versa. Further work is needed to understand and improve measurement noise. Until noise is reduced, studies will continue to find that structural and functional tests do not correlate when progression is evaluated. (David P. Crabb, London, UK)
4. Most studies evaluating progression report either the percentage of patients meeting an arbitrary criterion of change (incidence) or the time-to-progression using Kaplan-Meier survival curves. We should also be interested in the speed of change. The few studies that have looked at the rate of progression evaluated this in different ways. Quigley et al. 1996 and Broman, Quigley, et al. 2008 indirectly calculated the rate using x-sectional data in both treated and untreated patients. Data from the Collaborative Normal Tension Glaucoma study (CNTGS) and Early Manifest Glaucoma Trial (EMGT) provided rates directly in untreated eyes. Data from the Halifax Glaucoma Study provided rates directly from treated eyes. Systematic differences were found between studies that are explained by methodology & different risk profiles (IOP, race, baseline damage, age, therapy, type of damage). Some patients did have rates faster than mean which suggests the need to identify "rapid progressors" early. Still estimating rates in clinical practice is difficult, requiring a series of fields to be done in a relatively short period with unanswered questions of what rate is significant and how often should we do perimetry to detect these rates? (Paul H Artes Halifax, NS, Canada)
5. It is difficult to correlate visual field changes to visual disability in patients with glaucoma. This area is significant as a clinician would like to provide guidance on each of their patient's capabilities. When eye-hand coordination was studied in controls and individuals with glaucoma, patients with glaucoma exhibited slower movement, onset of movement was slower and the reach dynamics was more variable. When eye movements were studied in a similar group of individuals with glaucoma as well as in controls, the glaucoma patients would make a greater number of saccadic eye movements that were shorter in scope. When these groups were evaluated in regards to finding an object in a computer displayed image, glaucoma patients were slower. It is important that we link the stage of the disease to what patients can and cannot do. Eye movement studies might provide a window into the functional consequences of glaucoma. (David P. Crabb London, UK)
6. Glaucoma affects three areas in the posterior segment of the eye: the optic disc, peripapillary nerve fiber layer and the ganglion cell. Currently, we evaluate the optic disc and retinal nerve fiber layer though it has been demonstrated that ganglion cells within the macula area are reduced due to glaucoma. Still, macular retinal thinning is a relatively insensitive diagnostic parameter for glaucoma because glaucoma preferentially affects the inner retinal layers. One possibility to enhance the macula diagnostic usefulness may be automated computer measurement of the ganglion cell complex (GCC), which is made up of the axons (nerve fiber layer), body ( ganglion cell layer) and dendrites ( inner plexiform layer) . In a paper being revised for publication, we found that glaucoma predominantly causes thinning of the nerve fiber, ganglion cell and inner plexiform layers, moderately affecting the inner nuclear layer and not affecting the outer layers. (David Huang Los Angeles, CA)
7. High-speed mapping by FD-OCT improved the detection of nerve fiber layer loss in glaucoma due to greater sampling and improved resolution. FD-OCT improved the repeatability of nerve fiber layer measurement and offers the potential to track glaucoma over time. Also blood flow velocity measurements with the OCT may be possible. The OCT data shows that the venous flow peaks slightly lags behind the arterial flow peaks in time. The total retinal flow is measured by integrating the flow in all of the arterioles exiting the optic disc or all of the venules entering the optic disc. (David Huang Los Angeles, CA)
8. Glaucoma patient organizations (GPOs) can be an extremely meaningful piece of a patient's program of care. They provide a wide variety of support with membership typically comprised of newcomers and more experienced patients to provide balance. They are led by sensitive and caring leaders who can help offer comfort and foster sense of self esteem and courage for the difficulties that lie ahead. Meeting places include community health centers, local hospitals, churches and town meeting halls. Family members and friends are generally welcome as well. Others GPOs meet online. These groups usually offer news information, research updates, on-line counseling, chat rooms, e-mail bulletins and links to other resources. Web-based GPOs are particularly useful for those who live in remote or rural areas, those who are unable to physically travel and people who prefer anonymity. The landscape of health care has been altered forever. Patients have assumed a greater role in their own care, which is a positive development, but it puts a greater strain on medical professionals. Assistance and support from outside entities is warranted, necessary and welcome. (Scott R. Christensen, New York, NY USA)
9. Given that Latinos, one of the fastest growing segments of the population, have high rates of visual impairment related to open angle glaucoma, and that much of it is undetected, special attention should be paid to this group. This includes implementing screening and treatment programs for the Latino population (especially aging members), providing health insurance and better educating Latinos and other health-care professionals about the importance of eye care, especially in this population. We owe it to these patients to try to lower the burden of undetected eye disease in the population at large and in this particular ethnic group. (Rohit Varma, Los Angeles, CA)