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Improving drug adherence, making earlier diagnosis keys to meeting challenge of glaucoma
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The prevalence of glaucoma is rising, and it is estimated that in 2020 more than 11 million of the 80 million patients affected by the disease will become bilaterally blind.
Not only is this high number alarming, but so too is the fact that more than 50% of the patients with glaucoma in the developed world are undetected, not to mention the much higher percentage in developing countries.
Glaucoma creates a high financial burden on society. It is important to know that besides the direct costs related to diagnosis, monitoring and treatment, there are indirect costs that increase with progressive visual impairment and can amount to 50% of the total. Visually disabled patients lose the ability to be independent in their daily lives. Often they can no longer drive and need to rely on others to reach the places they want to go, to do their shopping, to visit a doctor. These indirect or surrounding costs are often underestimated.
Studies show that glaucoma not only affects vision, but it also has a heavy impact on patients’ quality of life. The diagnosis itself may generate a lot of anxiety and fear of becoming visually impaired or even blind, which often leads to depression. It is also known that at least two-thirds of glaucoma patients experience adverse effects from their glaucoma medications, which negatively influence quality of life.
Low adherence to medications is a common problem, leading to uncontrolled progression and increased costs. Although patients tend to deny their negligence in taking medications, studies show that the persistence rate tends to drop to only 50% 1 month after the start of a new therapy.
The fact that adherence and persistence rate have remained at the same low level over the last 25 years despite easier treatment schemes and increased patient awareness is certainly a matter for concern.
What else can we do to improve adherence and persistence and therefore reduce costs?
The first important task is to provide patents with all the information they need about the disease itself and the therapy, with all its implications. Patients should be made aware of what the diagnosis of glaucoma means and how they can prevent visual impairment.
The second most important task is to diagnose glaucoma earlier. Too many patients still do not know that they are affected by the disease. An earlier diagnosis of glaucoma helps to preserve vision and reduces the high costs caused by severe visual impairment.
The crucial role of technology
Technology has a crucial role in helping us to detect the early signs of glaucoma. Over the years, major advances have been made toward making monitoring devices increasingly sensitive, easy to use and cost-effective. Structural, clinical and functional tests have undergone substantial improvements.
Scanning laser ophthalmoscopy has been used since the 1980s but has recently made an important step forward with the introduction of adaptive optics that remove optical aberrations from the images. Optical coherence tomography has undergone an enormous evolution since its inception in 1990, and the latest-generation systems enable us to detect even small changes of the optic nerve and retina and therefore diagnose glaucoma much earlier.
An added benefit of the improved visualization of retinal and optic nerve structures is that patients themselves can see what is going on in their eyes and feel more directly involved in their treatment, thus likely improving their adherence.
Since the time of Hans Goldmann in the 1950s, Goldmann applanation tonometry has remained the gold standard for measuring IOP. More knowledge of the structure of the cornea, however, showed that other factors may influence the measurement of IOP. Newer devices such as the Ocular Response Analyzer (Reichert) or the Pascal dynamic contour tonometer (Ziemer) have the ability to measure IOP independently of the corneal thickness and therefore provide us with more precise data. New devices for continuous 24-hour pressure monitoring will soon be available.
Standard automated perimetry has been used for decades to measure the visual field. To improve the sensitivity to early damage, specialized perimetric tests that selectively assess visual function have been developed since the 1990s. These devices have not yet found their place in the daily practice. Standard automated perimetry has remained the gold standard for testing the visual field, but improving techniques will certainly give us new tools for better and earlier diagnosis of glaucoma.
Improving adherence to medications and diagnosing glaucoma earlier with the latest technology are key in meeting the challenge of glaucoma in future years.
- References:
- Oserberg L, et al. N Engl J Med. 2005;doi:10.1056/NEJMra050100.
- Quigley HA, et al. Br J Ophthalmol. 2006;doi:10.1136/bjo.2005.081224.
- Zimmerman TJ, et al. J Ocul Pharmacol Ther. 2009;doi:10.1089/jop.2008.0072.
- For more information:
- Frances Meier-Gibbons, MD, is an OSN Europe Edition Board Member. She can be reached at Tiefenaustrasse2, 8640 Rapperswil/SG, Switzerland; +41-552206522; email: frances.meier@bluewin.ch.
Disclosure: Meier-Gibbons is a consultant for Alcon, Allergan and MSD and a lecturer for Santen and Théa.