Medical Center

This group compared two non-mydriatic, stereoscopic 45¡ photographs of the macula and optic nerve, along with red-free images and colour images alone, to a dilated fundus examination [26]. Fourteen percent of the images were unable to be interpreted due to poor quality. They found that the addition of stereoscopic images with monochromatic views increased the sensitivity and speciÞcity (70.0% and 93.9%, respectively) for the detection of diabetic retinopathy in comparison to non-stereoscopic colour images alone.

3.4.4Joslin Vision Network

The Joslin Vision Network (JVN) teleophthalmology system uses non-mydriatic imaging to evaluate diabetic retinopathy. Their imaging system captures three 45¡ stereoscopic photographs that cover approximately 70% of the ETDRS standard seven Þelds [2, 6, 7]. Several studies have been published evaluating the detection and grading of diabetic retinopathy. Although one study showed substantial agreement (k =0.65) in the grading of diabetic retinopathy, 12% of the images were ungradable. Most of these ungradable images were a result of reduced stereo quality and therefore affected the evaluation of macular oedema [6].

Chow et al. [8] also compared their non-mydri- atic imaging in the detection of non-diabetic eye disease in diabetic patients to a dilated ophthalmic examination. They found that at least one nondiabetic ocular Þnding was discovered in 40.7% of patients, such as retinal emboli, chorioretinal atrophy or scars, choroidal lesions, epiretinal membranes, indicators of glaucoma, hypertensive retinopathy, age-related maculopathy and cataracts. There was a substantial to near perfect agreement (k 0.71 to ³0.80) between their imaging system and a dilated ophthalmic examination.

In a more recent study [2], their system was compared to a dilated fundus exam for the detection of diabetic retinopathy. Thirty-Þve percent of photographs were judged to be inadequate for grading because of lens opacities, image shadowing or misalignment. However, they found a

their digital imaging system and dilated fundus exams reviewed by record.

The JVN system incorporates non-mydriatic stereoscopic retinal photography and works to offer same-day retinal evaluation in a primary care or an endocrinology setting. While this system may have a higher percentage of ungradable images, this is a system that is striving to improve patient care in the management of diabetes mellitus.

3.5Conclusion

Stereopsis and the information that it provides are extremely important for both clinical ophthalmologists and those providing care via teleophthalmology. While some monoscopic systems have been validated for the identification of diabetic retinopathy and glaucoma, the gold standard remains stereoscopic imaging.

Teleophthalmology systems, in contrast to traditional clinical examinations, are used to extend the reach of specialists to patients that may have difÞculty accessing tertiary care. Inclusion of stereopsis in a teleophthalmology system will improve speciÞcity and reduce the number of unnecessary referrals. The technological barriers and patient discomfort from pupillary dilation, which is necessary to capture high-quality stereo photographs, are slight when compared to the beneÞts. Given the wide variety of imaging systems that can capture stereo photographs, teleophthalmology groups should consider the incorporation of stereopsis.

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4.1Introduction

Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycemia and causes both macrovascular and microvascular complications. Diabetic retinopathy (DR), the commonest microvascular complication of DM,

D. Ting ( )

Information and Communication Technology Centre,

The Australian e-Health Research Centre,

Commonwealth Scientific Industrial Research

Organization (CSIRO), 65 Brockway Road,

Floreat, WA 6014, Australia

Center for Ophthalmology and Visual Sciences, Lions Eye Institute, University of Western Australia, 2 Verdun Street, Nedlands, WA 6009, Australia e-mail: daniel_ting45@hotmail.com

K. Yogesan

Ocular Health Research Group, Australian e-Health Research Centre,

CSIRO, 65 Brockway Road, Floreat, WA 6009, Australia e-mail: kan063@csiro.au

I. Constable

Vitreoretinal Service, Center for Ophthalmology and Visual Sciences, Lions Eye Institute, University of Western Australia, 2 Verdun Street,

Nedlands, WA 6009, Australia

M.-L. Tay-Kearney

Ocular Inflammation and Uveitis,

Center for Ophthalmology and Visual Sciences, Lions Eye Institute, University of Western Australia, 2 Verdun Street, Nedlands, WA 6009, Australia

occurs in 25–40% of people with type II DM [1]. It is more prevalent among the type I diabetic as more than 90% of whom will develop DR after 20 years [2].

Given that diabetes is a huge burden to the society universally, it is important that primary eye care provider can be proactive in screening for DR in the community. In the past, DR screening has been performed by dilated fundoscopy by the primary eye care providers such as the general practitioners, optometrists, and other allied health-care workers. Following that, retinal still photography using retinal cameras has become the routine screening method to screen for DR in the primary health-care setting in most countries such as United States, United Kingdom, Australia, Europe, and Singapore.

Until recently, the use of video-based imaging technology has been proposed as a novel technique for DR screening [3]. Each retinal video takes 15–20 s to perform, and it provides a continuity of retinal view from optic disk to macula and temporal views. The retinal video is performed by a simple fundus camera which has retinal video recording function. This is an easy technique which can be performed by inexperienced personnel with minimal training. The purpose of this study is to evaluate the efficacy of this novel technique in screening for DR, with reference to the routine screening methods using retinal still photography and slit lamp examination (reference standard) for our study.