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Disclaimer: About 80% to 90% of this piece was written by Laurel A. Rockefeller. The other 10% to 20% was written by Arpi Haroutunian.

Laurel A. Rockefeller

Issue 2, September 17, 2004: Risk Supplement Program

Publication
Glaucoma Risk Factor Assessment and Prevention: Lessons from Coronary Heart Disease. Christopher Girkin, MD, MSPH; William B Kannel, MD, MPH; David S. Friedman, MD, MPH; Robert N. Weinreb, MD. Am J Ophthalmol 2004; 138 Supplement: S11-S18.

Discussion synopsis

• The authors summarize the literature on global risk assessment and prevention of CHD in clinical practice and discuss the development of glaucoma risk assessment based on the available data. They reviewed the potential for prevention strategies founded on the cardiovascular disease model and concluded that the systematic application of epidemiologic data to CHD risk factor models provides insights into how global risk assessment can be incorporated into treatment recommendations for managing individual patients with glaucoma.

• By examining the path to successful prevention of Coronary Heart Disease (CHD) through risk assessment, and applying it to data gathered in the Ocular Hypertension Treatment Study (OHTS), the reviewer is seeking to identify comparable risk factors for glaucoma with the aim of helping doctors create effective preventive treatment programs for their patients.

  • IOP in glaucoma is analogous to cholesterol in CHD in that it is a causal, modifiable risk factor.

  • Just as the ratio between total and HDL cholesterol is the best predictor of risk for CHD, IOP and corneal thickness both need to be assessed and balanced when predicting risk for glaucoma development along with diurnal fluctuation of IOP, as these three factors interact in glaucoma development.

  • Although IOP, corneal thickness, and diurnal fluctuations in IOP are the three most studied risk factors for glaucoma, several other risk factors such as diabetes mellitus, hypertension, and baseline optic disk characteristics are also important and require greater study to uncover the best prevention strategies for patients.

  • To improve risk assessment in glaucoma and develop disease management strategies for patients with OH, it is necessary to

    - Identify and quantify levels of risk associated with factors that predict disease progression
    - Assess the incidence of glaucoma and average life expectancy based on current age
    - Quantify how long it takes to develop a visual defect that affects quality of life once a person develops glaucoma.
    

• This review takes a hard look at both the known factors and unknown factors affecting risk assessment of glaucoma, pointing out where more research is needed and possible confounding variables to treatment such as the shifting definition of OH, relationship between corneal thickness and IOP, and age of patient to overall life expectancy.

  • Levels of risk of various factors affecting disease progression are still in the process of quantification.

  • Risk assessment requires estimating incidence of glaucoma development by age, relative to life expectancy.

  • The time between onset of glaucoma and affect on quality of life is still not quantified.

  • Hopefully, ophthalmologists will be able to use the results of future investigations and long-term studies to develop disease prevention strategies in patient OH based on multivariable risk assessment.

Strengths

• Dr. Girkin does a good job of drawing an analogy between the highly successive efforts to prevent CHD through cholesterol control and promising data regarding early IOP control and glaucoma prevention.

• This study points out not only the positive aspects for glaucoma prevention, but also fairly points outs its weaknesses. It identifies areas where further study is required in order to pin down who should be treated for glaucoma and at what levels of specific risk factors.

• The analysis identifies which three factors should be most closely examined by doctors in determining treatment: IOP, corneal thickness, and diurnal fluctuations. At the same time, it identifies interactions between these factors while reminding doctors that "normal" ocular tension has yet to be permanently defined.
  

Conclusion
While there is still much to learn about how different risk factors interact with each other, the overall treatment of risk versus disease in glaucoma, and what constitutes "normal' in the general population, it is currently useful for a doctor to monitor diurnal changes in IOP, corneal thickness, and greater than average IOP levels.

BACK TO HOMEPAGE

Disclaimer: About 80% to 90% of this piece was written by Laurel A. Rockefeller. The other 10% to 20% was written by Arpi Haroutunian.