Glaucoma screening in the Northern Finland Birth Cohort Eye Study

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

Faculty of Medicine, Leena Palotie -auditorium (Aapistie 5A)

Topic of the dissertation

Glaucoma screening in the Northern Finland Birth Cohort Eye Study

Doctoral candidate

Doctor of Medicine Elina Karvonen

Faculty and unit

University of Oulu Graduate School, Faculty of Medicine, PEDEGO Research Unit

Subject of study

Ophthalmology

Opponent

Assistant Professor Mika Harju, Helsinki University Hospital, University of Helsinki

Custos

Docent, Chief Physician Ville Saarela, Oulu University Hospital

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Glaucoma screening in middle-aged population

Glaucoma, ‘a silent thief of sight’, affects 80 million people globally. Of them, at least 8 million are visually impaired or blind. In Finland, nearly 100,000 persons have glaucoma, which is the second major cause of visual impairment in the age group of 65-year-olds and older. Glaucoma is usually asymptomatic until the late phase of the disease. Therefore, it is often diagnosed in persons attending ophthalmic evaluation for other reasons. It has been estimated that at least half of the glaucoma cases are still undetected. However, population screening is not recommended due to lack of evidence on its impact on reducing visual disability. The best screening strategy is also unknown.

The Northern Finland Birth Cohort (NFBC) Eye Study is a prospective study evaluating eye morbidity during the lifespan. The most recent health examinations were conducted at the age of 46 years. The cohort was randomised to an eye examination group and a control group. In this thesis, we examined 3,000 cohort members attending the eye study, with emphasis on glaucoma evaluation. Definite glaucoma was found in 1.1% of the persons. Roughly 90% of them did not have earlier glaucoma diagnosis and almost 90% had normal eye pressure.

We also evaluated the performance of the modern eye imaging devices in glaucoma screening. Their results were compared to conventional glaucoma assessment which is based on the evaluation of the optic nerve head and retinal nerve fibre layer photographs and visual fields. The sensitivities of the modern imaging tests detecting glaucoma in healthy middle-aged population were modest, only 61% at their highest. Combination of modern imaging and visual field testing improved the accuracy of glaucoma detection in this study population. However, even the best combination of the tests detected only eight out of ten glaucoma cases and created 14-fold number of false positives compared with true glaucoma cases. Such a screening strategy would seriously burden both individuals and the healthcare system.

The tests evaluated in this cross-sectional study setting are not suitable for glaucoma screening in the middle-aged general population. In the future, both groups will be evaluated, enabling evaluation of the effectiveness and cost-effectiveness of glaucoma screening in preventing visual disability.
Last updated: 30.3.2022