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Raw data from Ocular Response Analyzer applied for differentiation of normal and glaucoma patients

Jóźwik Agnieszka, Asejczyk-Widlicka Magdalena, Boszczyk Agnieszka, Kasprzak Henryk, Krzyżanowska-Berkowska Patrycja

Optica Applicata

2020

Vol. 50, nr 1

147--159

Purpose: Presented study describes new parameters calculated from the Ocular Response Analyzer (ORA) raw data. Such an approach can increase the applicability of the ORA in ophthalmic diagnosis. Among many proposed and examined by us parameters from raw data of the air pressure and applanation curves, only a few were chosen and then applied for characterizing a selected group of patients. Methods: The study included healthy subjects in a control group and patients divided into 2 groups: suspect and glaucoma. A series of four ORA measurements were taken from each subject. The raw ORA data were numerically analyzed and new parameters were calculated from the ORA curves for each measurement. Comparative analysis was carried out for the newly proposed parameters (and original parameters from the ORA device). Results: This interesting finding is that the new parameters showed a statistically significant ability to distinguish the glaucoma suspect group from healthy and glaucomatous patients. Moreover comparable or higher repeatability than for IOPg and CH was obtained. Conclusion: Raw data from the ORA enables definition and numerical analysis of new parameters, characterizing every measurement, which can be successfully used for describing an individual eye and differentiating between some specific groups of patients.

Stable distribution in application to fixational eye movement description

Szmigiel Marta, Grzesiek Aleksandra, Wyłomańska Agnieszka, Kasprzak Henryk

Optica Applicata

2019

Vol. 49, nr 2

365--377

To give an appropriate description of fixational eye movements is a very challenging problem. Over the years authors tried to describe the movements through different methods. The time series of the movements exhibit very characteristic behavior, which is the visible impulses. This may suggest the heavy-tailed distribution behind the data. In this paper on stochastic description of fixational eye movements, the α-stable distribution as the most important member of heavy-tailed family of distributions is proposed. The fixational eye movements together with head movement of both eyes of eight healthy subjects were measured and recorded by use of own designed optical system. Further analysis of changes in position of the pupil center in two-dimensional plane was performed. It was shown that head movement has very small impact on values of stability parameter α of fixational eye movements. The α-stable based analysis can be useful in better understanding of the character of the eye globe dynamics.