Page 16 - Computational Retinal Image Analysis

CHAPTER

Clinical motivation and the

needs for RIA in healthcare 2

b
a
Ryo Kawasaki , Jakob Grauslund
a Department of Vision Informatics, Osaka University Graduate School of Medicine, Suita, Japan,
b Department of Ophthalmology and Department of Clinical Research, Odense University Hospital
and University of Southern Denmark, Odense, Denmark

1 Introduction
The retina provides a unique window to observe blood vessels and neural tissue
in vivo. The intervention of the ophthalmoscope by Hermann von Helmholtz in 1851
has uncovered the retina behind the pupil of the eye [1]. Observing the retina and the
optic disc has formed the foundation of modern ophthalmology by describing ocular
diseases in detail.
Ophthalmologists diagnose retinal diseases by identifying specific signs on the
retina. In the clinical setting, the primarily method to examine the retina is through
direct or indirect ophthalmoscopy. Expanding use of retinal photographs contributed
to retinal image analysis tremendously. Not long since the invention of photography,
Jackman and Webster reported the first fundus photography in 1886 [2]. Carl Zeiss
produced the first commercial fundus camera in 1926. Since then, fundus photography
has been used as the main imaging modality in clinical settings. In the 1970s, the non-
mydriatic fundus camera was introduced to the market and it contributed to expanding
the field of fundus photography use to health screening programs or epidemiological
studies. In the early days, retinal image analysis was done by literally applying scales
or a Vernier caliper on the films or projected images on a large screen (e.g. measur-
ing vessel caliber, optic disc diameter, and standard circles for signs of age-related
macular degeneration). At that time, as one can imagine, retinal image analyses were
limited because of its workload and so mainly used for research purposes.
Landmark expansion of retinal imaging was achieved by a transition from film to
digital image. Digital fundus camera was introduced by Eastman Kodak in 1975. It
took several decades to fully shift from analog film to digital imaging by persuading
clinicians to accept color replication and high resolution to capture subtle changes on
the retinal images (and maybe cost of the equipment). Digital fundus photography is
now the standard imaging modality in both ophthalmic clinics and screening facili-
ties. Since the inclusion of a digital camera along with matching computing power

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