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Excerpt from Paul Lichter on 'Practice and RCTs' (Editorial in the American Journal of Ophthalmology)
Erik Greve
In an editorial in the American Journal of Ophthalmology, Paul Lichter presented a balanced opinion on the contribution of RCTs to the management of Glaucoma. He described the paradox of RCTs: by nature they exclude variability and individuality. They deal with one question. In daily clinical practice, there are a multitude of factors, great variability, and an individual approach. Lichter stresses Quality of Life as the endpoint; conversion to early glaucomatous defects is not similar to reduced Quality of Life: "Early detection of visual field loss helps me in knowing who to watch more closely for further change, not in telling me whom to treat."
Patients with OH or early glaucoma may be followed carefully without treatment, without compromising Quality of Life: "We should recognize that letting the patients progress - under careful observation - to frank glaucoma before treating them will still allow for control of the disease in the vast majority of patients."
Lichter stresses an option to follow-up "until frank glaucoma" on the one hand, and on the other, the possibility for us to treat patients - once the indication is there - in such a way that future reduction of Quality of Vision is improbable. This treatment may need reductions in IOP of 30-40%.
If you have not yet read this editorial, I can highly recommend it.
My only addition would be the notion of Rate of Progression (see IGR 4-3, Greve and Hitchings).
Lichter's results and conclusions (Abstract no. 604)
Results: Glaucoma clinical trials and observational studies strongly support the need to reduce intraocular pressures (IOP) substantially and to maintain those pressures in patients with advanced glaucoma. Whether this aggressive therapy occurs by medications or by filtering surgery does not seem as important as that the treatment is effective and sustained. However, there is not the same strength of evidence for aggressive treatment or even any treatment for most patients with ocular hypertension and for some cases of early glaucoma. Because about half of the patients with open-angle glaucoma will have IOPs less than 21 mmHg, these patients need to be detected through careful optic disk and visual field assessment. Once patients are detected and treated appropriately, blindness from open-angle glaucoma is unlikely.
Conclusions: The goal of managing ocular hypertension and glaucoma is not to preserve every ganglion cell, but rather to preserve a patient's visual ability to conduct activities of daily living. Risk factors for damage need to be assessed for individual patients and each patient managed as an individual and not as the 'average' patient depicted in the results of clinical trials. In the future, neuroprotective therapy other than IOP reduction will provide another means to control glaucoma damage.
