Estimating the Length of the Preclinical Detectable Phase for Open-Angle Glaucoma

Area of Science:

• Ophthalmology
• Public Health
• Biostatistics

Background:

• Open-angle glaucoma screening can reduce blindness by 50%.
• Future screening may become more widespread due to ongoing trials and new technologies.
• Estimating the mean preclinical detectable phase (PCDP) is crucial for planning and evaluating screening programs.

Purpose of the Study:

• To estimate the mean preclinical detectable phase (PCDP) for open-angle glaucoma.

Main Methods:

• A population-based screening for open-angle glaucoma was conducted in Malmö, Sweden (1992-1997) with 32,918 participants.
• Retrospective medical record review assessed screening-detected cases, post-screening incidence, and expected clinical incidence.
• The mean PCDP was calculated using two methods: prevalence/incidence ratio and Markov chain Monte Carlo (MCMC) simulation.

Main Results:

• The study included 2029 patients; 66.6% were female.
• The mean age of screened patients was 67.4 years.
• The mean PCDP was estimated at 10.7 years (prevalence/incidence) and 10.1 years (MCMC), with both methods yielding similar results.

Conclusions:

• The mean PCDP for open-angle glaucoma is approximately 10 years.
• This 10-year PCDP suggests that screening intervals of up to five years are feasible.
• The findings are essential for optimizing glaucoma screening strategies and early detection programs.