Emergency eye care in rural Australia: role of internet

PURPOSE: Significant differences exist in the utilization of emergency eye care services in rural and urban Australia. Meanwhile, influence of internet-based technology in emergency eye care service utilization has not been established. This study aims to demonstrate, from a health provider perspective, an internet-based service's impact on emergency eye care in rural Australia. METHODS: The teleophthalmology service was initiated in the Carnarvon Regional Hospital (CRH) of the Gascoyne region in Western Australia. A digital, slit lamp and fundus camera were used for the service. Economic data was gathered from the Department of Health of Western Australia (DOHWA), the CRH and the Lions Eye Institute. RESULTS: During the study period (January-December, 2003) 118 persons took part in teleophthalmology consultations. Emergency cases constituted 3% of these consultations. Previous year, there were seven eye-related emergency evacuations (inter-hospital air transfers) from the Gascoyne region to City of Perth. CONCLUSIONS: Analysis demonstrates implementation of internet-based health services has a marked impact on rural emergency eye care delivery. Internet is well suited to ophthalmology for the diagnosis and management of acute conditions in remote areas. Integration of such services to mainstream health care is recommended.     

Glaucoma screening: analysis of conventional and telemedicine-friendly devices

PURPOSE: Portable, telemedicine-friendly devices offer novel opportunity for screening and monitoring glaucoma in the remote and rural regions of the world. This study examines the effective combination of telemedicine-friendly screening devices for detection of glaucoma in relation with conventional, hospital-based devices. METHODS: A total of 399 eyes were screened with telemedicine-friendly devices and conventional, hospital-based devices such as ophthalmoscope, tonometer and perimeter. RESULTS: Combination of age and family history of glaucoma alone has a sensitivity of 35.6% (specificity 94.2%, area under the curve 0.81, correctly classified 81.1%) and an addition of telemedicine-friendly or conventional visual field tests optimized the sensitivity to 91.1% (specificity 93.6%, area under the curve 0.95, correctly classified 93%). Analysis indicates good agreement between vertical cup-to-disc ratio by ophthalmoscopy and digital image reading. An addition of intraocular pressure test does not change sensitivity (35.6%) and specificity (94.2%). CONCLUSION: This study indicates that evaluations of cup-to-disc ratio and visual field, using telemedicine-friendly devices, are most useful tools in screening for glaucoma. When used together these devices may be an alternative for conventional glaucoma screenings.     

Microvascular changes at different stages of chronic kidney disease

Patients with progressing chronic kidney disease (CKD) are more likely to experience cardio‐ and cerebrovascular events than progressing to end‐stage renal disease. The authors explored whether retinal microvascular calibers differed with the degree of renal impairment and between the standard and extended optic disk and may serve as a simple additional tool for risk stratification in this highly vulnerable patient cohort. The authors analyzed central retinal arteriolar and venular equivalent calibers (CRAE, CRVE) at different retinal zones (zone B&C) using digital retinal imaging in hypertensive patients with stage 2 (n = 66) or stage 3 CKD (n = 30). Results were adjusted for age, sex, HbA1c, and 24‐hour diastolic blood pressure. Mean eGFR was 77.7 ± 8.9 and 48.8 ± 7.9 ml/min/1.73 m² for stage 2 and 3 CKD, respectively. CRAE and CRVE in zones B and C were significantly lower in patients with stage 3 CKD compared to patients with stage 2 CKD (CRAE‐B:141.1 ± 21.4 vs. 130.5 ± 18.9 µm, p = .030; CRAE‐C:137.4 ± 19.4 vs 129.2 ± 18.2 µm, p = .049; CRVE‐B:220.8 ± 33.0 vs. 206.0 ± 28.4 µm, p = .004; and CRVE‐C:215.9 ± 33.0 vs. 201.2 ± 25.1µm, p = .003). In patients with stage 2 CKD, CRAE‐B was higher than CRAE‐C (141.1 ± 21.4 vs. 137.4 ± 19.4µm, p < .001). In contrast, such a difference was not found in patients with stage 3 CKD. CRAE of both retinal zones correlated with eGFR for the entire cohort. In patients with stage 3 CKD, retinal narrowing is more pronounced compared to patients with stage 2 CKD. Whether the novel observation of difference in arteriolar caliber between zones B and C in stage 2 CKD could serve as an early marker of CKD progression warrants further investigation.     

Fred Hollows lecture: digital screening for eye disease

The purpose of this study was to explore progress, in the adaptation to community screening for blinding eye disease, of digital imaging devices and technology for storage and transmission. Available imaging systems were compared to gold standard clinical photography in terms of sensitivity and specificity for diagnosis of common blinding eye conditions. Since the use of expensive non-portable imaging devices is likely to be limited for widespread community screening purposes, a portable fundus camera (Nidek, Chiyoda-ku, Japan) and a prototype monocular digital indirect ophthalmoscope constructed at the Lions Eye Institute (LEI) were selected for comparative trials for the screening of optic disc cupping, glaucoma and clinical signs of diabetic retinopathy. Fifty-one eyes of 27 consecutive patients being assessed at the LEI clinic for glaucoma were dilated and photographed with a Zeiss retinal camera, and digital images were taken with the portable Nidek NM100 fundus camera (Carl Zeiss, Oberkochen, Germany) or with a prototype digital monocular indirect ophthalmoscope. Vertical cup: disc ratios (VCDR) were measured on the disc photographs by one ophthalmologist while three other clinicians were presented with compressed digital images in random order to estimate VCDR. Field trials were also carried out to demonstrate the practicality of compression, local storage and then transmission by mobile telephone ISDN lines and satellite, of optic discs and fundus images of patients with diabetes in either rural Western Australia or Surabaya, Indonesia. Kappa values of correlations of measurement of agreement between measured and estimated VCDR were 0.87, 0.45 and 0.84, respectively, for the three observers, corresponding to a specificity of 79-97% and a sensitivity of 70-95%. The portable Nidek fundus camera was also assessed for specificity and sensitivity in the diagnosis of diabetic retinopathy in comparison to standard Zeiss fundus camera photographs. Of 49 eyes in 25 consecutive patients attending the LEI clinic for assessment of diabetic retinopathy, three ophthalmologists assessed photographs and images in random order. When used for screening diabetic retinopathy, the digital images of the Nidek camera were graded as adequate quality in only 56% of eyes compared to 93% of the photographs. The kappa value of agreement in analysis of diabetic retinopathy was only 0.30. The prototype digital monocular indirect ophthalmoscope compared favourably with the Nidek camera. At 1:5 compression, images of size 36 kB transmitted from Surabaya to Perth took 29 s on the mobile telephone, while uncompressed images took 170 s. Images compressed 1:5 were transmitted in 60 s using the satellite telephone, while the uncompressed images took 240 s. Satellite transmission was more expensive but the lines were more stable than telephone connections from Indonesia. Digital imaging is becoming a powerful tool for ophthalmology in clinical records, teaching and research, and interoffice diagnostic opinions. It also has enormous potential for community screening for blinding eye diseases, such as glaucoma and diabetic retinopathy. Inexpensive portable imaging devices that are easy to use, and on which local health workers might be trained, must be developed and validated in terms of sensitivity and specificity of performance. The technology of image capture, image compression, transmission, data base storage and analysis is rapidly evolving and becoming less expensive.     

Diabetic screening in Western Australia: a photographer's perspective

Western Australia has a large landmass and low population density. Dating back to the 1970s and even today, specialist medical services are often lacking or non-existent outside of Perth, the capital city. Diabetes has always been a major health problem, particularly in the Australian Aboriginal community. In conjunction with the Lions Save Sight Foundation and Diabetes Foundation of Western Australia a diabetic screening programme was initiated in 1978 for rural and remote diabetics. The programme aimed to screen for diabetic retinopathy, educate diabetics, medical and paramedical personnel and to arrange treatment for sight threatening eye disease. Eye screening continues to date although the role of the Lions Eye Institute has changed from programme initiator to reading centre and teaching unit, and continues to evolve with changing technologies.     

Tele-ophthalmology screening for retinal and anterior segment diseases

A digital indirect ophthalmoscope (DIO) was developed and tested for use in tele-ophthalmology screening for posterior and anterior segment diseases. Using custom software, images from the DIO were digitized, compressed, stored and transmitted to a centralized eye clinic for interpretation. A total of 43 subjects were primarily screened for glaucoma using the DIO, a hand-held fundus camera and a stereo fundus camera. The photographic slides from the stereo fundus camera used as gold standards. Images (390 x 300 pixels x 3 bits) were stored using a laptop computer together with patient information. Image quality received at the central eye clinic was good and showed adequate diagnostic information. An ophthalmologist estimated cup-disc ratios and graded the quality of the images. The sensitivity and specificity of each instrument was calculated. A high sensitivity and specificity was found when using the DIO, indicating that it could be used in tele-ophthalmic screenings. Further modifications are needed to make the instrument more user-friendly and to enable it to be used with undilated pupils, so that it can be easily operated by health-care personnel in remote areas. The camera can also be used to image gross external eye pathology.     

Retinal image analysis: concepts, applications and potential

As digital imaging and computing power increasingly develop, so too does the potential to use these technologies in ophthalmology. Image processing, analysis and computer vision techniques are increasing in prominence in all fields of medical science, and are especially pertinent to modern ophthalmology, as it is heavily dependent on visually oriented signs. The retinal microvasculature is unique in that it is the only part of the human circulation that can be directly visualised non-invasively in vivo, readily photographed and subject to digital image analysis. Exciting developments in image processing relevant to ophthalmology over the past 15 years includes the progress being made towards developing automated diagnostic systems for conditions, such as diabetic retinopathy, age-related macular degeneration and retinopathy of prematurity. These diagnostic systems offer the potential to be used in large-scale screening programs, with the potential for significant resource savings, as well as being free from observer bias and fatigue. In addition, quantitative measurements of retinal vascular topography using digital image analysis from retinal photography have been used as research tools to better understand the relationship between the retinal microvasculature and cardiovascular disease. Furthermore, advances in electronic media transmission increase the relevance of using image processing in 'teleophthalmology' as an aid in clinical decision-making, with particular relevance to large rural-based communities. In this review, we outline the principles upon which retinal digital image analysis is based. We discuss current techniques used to automatically detect landmark features of the fundus, such as the optic disc, fovea and blood vessels. We review the use of image analysis in the automated diagnosis of pathology (with particular reference to diabetic retinopathy). We also review its role in defining and performing quantitative measurements of vascular topography, how these entities are based on 'optimisation' principles and how they have helped to describe the relationship between systemic cardiovascular disease and retinal vascular changes. We also review the potential future use of fundal image analysis in telemedicine.