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Top-Eight of the Optometric Glaucoma Society Annual Meeting
December 6, 2006, Denver, Colorado
Murray Fingeret, John Flanagan and Mike Patella
- Patient adherence to prescribed drug therapies is better with prostaglandins, followed by beta blockers, topical CAIs and Alpha Agonists. Adherence rates vary from study to study, suggesting that adherence may depend significantly upon the patient-caregiver relationship. Managed care data have shown that approximately 50% of newly diagnosed POAG patients did not return for follow-up in the first 15 months, and that there was a relationship between therapeutic persistence and failure to return for follow-up.
- Many patients over-reported the number of drops they took. Reasons given for not taking their medications include cost, forgetfulness, side effects, fear of side effects, depression, and doubts about efficacy. Risk of poor adherence is higher in patients whose information about glaucoma came only from their doctor, those who have trouble paying for their medication, and those who forget to use their eyedrops when traveling.
- Assessment of patient adherence to therapy depends strongly upon interviewer technique. Open-ended questions, such as: Tell me how you have been taking your medication, often are useful. Assessment improves in a non-judgmental environment in which the patient becomes an active participant in care delivery.
- Measurements of structural and functional glaucoma damage in Macaque monkeys and in human subjects suggest that standard automated perimetry (SAP) and optical coherence tomography (OCT) provide concordant measures of retinal ganglion cell (RGC) populations. Structural and functional measurements may be used to provide confirmation of each other. Measurements in humans and monkeys demonstrated that, in cases of disagreement, SAP generally indicated greater loss of RGCs than was seen in the RNFL, suggesting that measured functional losses frequently precede measured structural changes
- Anterior segment OCT (ASOCT) measurements identified 98% of subjects found to have closed angles on gonioscopy and revealed significant numbers of closed angles in patients who were found to be open on gonioscopy. Incomplete agreement between ASOCT and gonioscopy may have been due to differences in lighting, distortion of the anterior segment by gonioscopy, and/or the use of different anatomical landmarks for the two methods. ASOCT may also have utility in post-operative imaging of trabeculectomy blebs.
- Patients of Chinese ancestry are at higher risk for ACG, but do not have proportionately higher numbers of small eyes compared to European populations. Anatomical size dos not completely explain observed differences in ACG risk.
- Some eyes having angle closure glaucoma may have a component of poor vitreous fluid conductivity, intensifying resistance to aqueous movement into the anterior chamber and aggravating pupillary block.
- Relatively small amounts of choroidal swelling may have significant effects on anterior chamber depth. Such swelling may be a contributing factor to pupillary blockage and angle closure.
- Experimental studies of laboratory animal-derived RGCs in vitro can provide insight into the characteristics that distinguish between functional and dysfunctional RGCs. Exposing purified rat RGC cultures to lethal and non-lethal levels of the excitatory neurotransmitter glutamate demonstrated that RGCs undergoing excitotoxic death displayed a latent loss in calcium homeostasis.
- Trend-based analyses of structural and functional measurements have advantages over event-based methods in the determination of progression rates, and are particularly advantageous when many examinations are available. Although event analysis may identify progressive test locations with as few as three test results, such methods require that the degree of measured change exceed test-retest variability, which may be high in areas of significant damage.
