Worldwide Glaucoma 2000
Baltimore, Maryland, USA, May 6-7, 2000
Hosted by the Dana Center for Preventive Ophthalmology, Johns Hopkins University School of Medicine and School of Hygiene and Public Health, Baltimore, Maryland, USA
Cosponsored by the World Health Organization
1. EXECUTIVE SUMMARY
A group of those interested in blindness prevention were invited to a two-day discussion cosponsored by the World Health Organization (WHO) to evaluate the present status of glaucoma diagnosis and treatment in the world. The attendees represented academic and practicing eye care professionals, as well as representatives of non-governmental organizations and business firms interested in the subject. It is widely recognized that glaucoma is a major cause of blindness in the world, but its diagnosis and therapy have not been included in active eyecare programs in many developing countries. An initial meeting to discuss why this is the case and what might be done to improve the situation was held in Jamaica in 1993 ("Glaucoma in the Developing World").
At the Jamaica meeting, initial estimates of glaucoma prevalence and blindness were reviewed, and its disproportionately greater impact on the developing world was documented. Most of those affected were undiagnosed and treatments were considered both unproven in effectiveness, generally unavailable, and often unacceptable in major population groups. No successful screening approaches were available for either open-angle or angle-closure glaucoma. There were no existing examples of successful integration of glaucoma management into the health care systems of any developing country, and the models of glaucoma care in the developed world were too expensive and possibly inappropriate for the disease elsewhere.
From 1993 to 2000, a variety of developments improved the situation, providing hope that a second discussion would be valuable. More than a dozen, new population-based prevalence surveys had been carried out in North America, among Hispanic persons, in Europe, Australia, Africa, Mongolia, and Singapore. These gave better data for the number affected, their geographic distribution and type of disease. Treatment options began to be explored, with some clinical trials of trabeculectomy surgery and greater availability of more affordable eyedrop therapy in some countries. The FDT screening visual test was developed, inspiring hope for better identification of cases, and the definitive, threshold test made by Zeiss-Humphrey was improved by speeding its test algorithm. Field studies of the diagnosis of angle-closure glaucoma in Asia were completed to improve diagnosis of this condition.
At the Worldwide Glaucoma 2000 meeting, there were introductory presentations, followed by division into 5 working groups that discussed assigned areas and questions. These dealt with open-angle and angle-closure glaucoma, their diagnosis or therapy, and a group devoted to the role of glaucoma care in overall eye and health care programming. All attendees then participated in joint discussion of the findings from each working group and summaries were prepared. Action plans were developed that indicate areas in which progress could be made in the near future. This executive summary provides a synopsis of the findings and recommendations, followed by the detailed proceedings.
A. OVERALL ACTION NEEDED
1. Develop by 2005 a comprehensive, evidence-based diagnosis and management program for angle-closure and open-angle glaucoma worldwide.
2. Define whom to treat, how to treat them, and training needed for the health care personnel who carry out the program.
3. Estimate costs related to treatment, visual impairment and blindness in present health care settings and after implementation of the 2005 program.
B. ANGLE CLOSURE GLAUCOMA
1. DEFINING THE NARROW ANGLE
a. Compare methods of diagnostic gonioscopy (Goldmann 1 mirror, Posner 4 mirror, biometric method, and Koeppe) for usefulness, predictive power, ease of learning by ophthalmologists and non-ophthalmologists, and practicality in field settings.
b. Develop a surrogate method for primary angle closure (PAC) diagnosis that is validated against gonioscopy, with possible methods to include van Herick assessment, hand light test, ultrasound, and optical pachymetry.
2. NATURAL HISTORY OF PRIMARY ANGLE CLOSURE
a. Estimate risk of PAC progressing to primary angle closure glaucoma (PACG), with functional loss (including field loss and blindness), both in persons who have and have not undergone iridotomy through longitudinal study of relevant populations
3. TREATMENT OF PAC AND PACG
a. Determine the best method for performing iridotomy (neodymium:YAG versus continuous wave or both) in major ethnic groups; and evaluate the production of a better laser for developing country use that would be cheaper, capable of performing iridotomy, suturelysis, capsulotomy, laser trabeculoplasty, and ciliodestruction.
b. In PACG, compare iridotomy to initial trabeculectomy as the most effective initial treatment, either through clinical trial or by longitudinal study (retrospective or prospective) of PACG treated by iridotomy with defined success rates.
C. OPEN ANGLE GLAUCOMA
1. DEFINING OPTIC NERVE DAMAGE
a. Test the utility of an operational classification of optic disc damage using criteria defined by the 97.5th percentile for vertical cup/disc ratio of each population. This would be tested using existing population-based prevalence survey data, comparing diagnosis of glaucoma used in a survey to the proposed classification scheme for each ethnicity. Evaluate differences among various ethnic groups. An associated issue is to determine how often a cup/disc ratio of 0.9 or greater is NOT glaucoma.
b. Determine what features of the optic disc other than the cup/disc ratio differentiate glaucoma damage from normal and non-glaucoma disease and develop practical methods to measure this attribute(s). E.g., what is it that "glaucoma experts" use to define glaucoma damage when they look at the disc and how can it be quantified and taught. Test whether scanning laser ophthalmoscopes should become the standard for identifying disc damage, replacing cup/disc ratio by features such as cup shape measure.
c. Evaluate the FDT technique for identifying those with glaucoma damage in population-based samples, validating its findings against threshold perimetry in each ethnicity. Develop a battery-operated, head-mounted, less expensive instrument using FDT technique
d. Develop screening guidelines that take into account the effectiveness of the methods and the age at which maximum yield of case identification and prevention of blindness can be achieved.
e. Determine the spectrum of visual field loss in each population and its functional consequence by assessment of a meaningful quality of life measure.
f. Determine the risk of blindness for PACG and open-angle glaucoma (OAG) in each population and factors identifying those at risk during their lifetime to define those in greatest need of treatment. Establish criteria for those in whom the risk of aggressive therapy is less than the risk of blindness.
D. TREATMENT OF OAG AND PACG
1. Survey present treatment methods in each major ethnic group, determining outcomes from present practice.
2. Conduct clinical trials of medical, laser and surgical methods of lowering IOP in various settings using either surrogate outcomes or optimal functional measures.
3. Develop a new (or test existing) simple filtering surgery devices or plugs.
4. Develop new outcome measures that are more relevant to those affected by glaucoma in world populations.
5. Engage those organizations with resources and societal responsibility to affect glaucoma blindness, including National Physician and Optometry Societies, Prevention of Blindness Committees, and NGOs.