Alvydas Paunksnis

The use of information technologies for diagnosis in ophthalmology

In 2003, a health IT programme for clinical decision support started in Lithuania. An initial goal was to create databases for ophthalmology images and to develop processing algorithms to extract diagnostically valuable information from images. We have investigated how vectors, consisting of the parameters derived from fundus images, are distributed and whether they form specific groups. When analysing the multidimensional patient data vectors, comprising all the 27 image parameters, it was impossible to separate the healthy eyes from the diseased ones. However, it was possible to simplify the system by eliminating redundant parameters and introducing new ones that represent a subset of parameters from the initial group. Thus it may prove possible to identify glaucoma using this system of parameters.

Parameterization of the Optic Nerve Disk in Eye Fundus Images

Algorithms for interactive and automatic optic nerve disk parameterization are presented in this paper. Parameterization of the optic nerve disk is done by detection of the disk boundaries and calculation of parameters describing it. Automatic and interactive algorithms and user interface are designed and implemented in Matlab (The MathWorks, Inc.) programming environment. Interactive identification of the optic nerve disk boundaries was done by experienced ophthalmologist. Reference points interactively placed by physician on the nerve disk boundary then approximated by ellipse. Those boundaries were used as reference boundaries for the evaluation of automatic boundaries detection algorithm. Automatic algorithm is based on removing of vessels by segmentation and approximation and then using derivative image and verification algorithm to determine boundary location. Optic nerve disk boundary is then approximated by ellipse. Comparison of interactive and automatic algorithms shows that automatic algorithm worked well enough on more than 80% of images (in 300 images dataset).

Morphometric parameters of the optic disc in normal and glaucomatous eyes based on time-domain optical coherence tomography image analysis

BACKGROUND AND OBJECTIVE Assessment of optic disc morphology is essential in diagnosis and management of visual impairment. The aim of this study was to evaluate associations between optic disc morphometric parameters, i.e., size and shape, and age, gender, and ocular axial length in normal and glaucomatous eyes based on time-domain optical coherence tomography image analysis. MATERIALS AND METHODS It was a case-control study of 998 normal and 394 eyes with primary open angle glaucoma that underwent an ophthalmological examination and time-domain optical coherence topography scanning. Areas and shapes of the disc, cup, and neuroretinal rim were analyzed. RESULTS The shape of the optic disc did not differ between the study groups, i.e., normal and glaucomatous case groups, but the disc area of the primary open angle glaucoma group was significantly larger. The shape of the small disc was significantly different, but the shape of the medium and the large disc did not differ between the study groups. The central area of the disc, i.e., cup area was significantly larger in the case group and its shape was significantly different between the study groups. No significant differences in the area of the cup and its shape, nerve fibers on the edge of the disc, i.e., neuroretinal rim area, were found between the study groups of the small discs. There were significant associations between age, gender, and ocular axial length and morphometric parameters of the optic disc. CONCLUSIONS Informative results with regard to the size and shape due to various ocular characteristics between the healthy control group and patients suffering with primary open angle glaucoma were obtained. Both study groups were significant in size, which makes the findings interesting and important contribution in the field.

Automatization of Eye Fundus Vessel Width Measurements

Many diseases can be early detected from eye fundus images by several different features. One of the features is the artery and vein ratio. Width measurement is made on the main vessels. The aim of this automatization process is to create a fully automated method for eye fundus analysis. The fully automated system consists of blood vessel tree extraction and optic nerve disc detection in order to perform measurements at the standard place. Vessel tree extraction is complicated in some situations, so the vessel measurement algorithm is developed independently of the extracted blood vessel tree, and the tree is used only for direction enhancement and only when it is available. Vessel measurements are compared with manual measurements, performed by an expert. Automated measurements are not different from the expert’s measurements with the confidence level of 95%. For this investigation, the Optomed OY digital mobile eye fundus camera Smartscope M5 PRO was used, but the algorithm can be used on any type of eye fundus images.

Application of Teleophthalmology in Screening and Monitoring of Elderly Population in Rural Areas in Lithuania

A small regional telenetwork has been established in Lithuania and used for piloting homecare and remote care health care service delivery models on the grounds of the work of the Telemedicine Centre of the Lithuanian University of Health Sciences (formerly Kaunas University of Medicine) and private initiative of clinicians and researchers with the aim to promote bottom-up, self-sustainable telemedicine development and to increase accessibility to, and quality of, healthcare especially in rural or underserved areas. Stratelus, a small medical company, together with several family clinics in the rural areas of Lithuania and with support of the Family Medicine Centre of the Kaunas University of Medicine started screening and monitoring of elderly population for diabetic retinopathy, aging macular degeneration, optic nerve head evaluation, and glaucoma in their homes and near-home locations, in a mobile telenetwork mode, bringing the access point to the patient. The project demonstrated innovation in terms of the methodology (telehomecare), organization (small bottom-up structure), and technology (high quality handheld fundus camera). The argument behind this project was to test the viability of homecare and remote care service delivery in a small/medium scale, bottom-up organisational setting. This is important for elderly population with limited mobility in rural or remote areas.