0000000000053555
AUTHOR
Gunta Krūmiņa
Visual Acuity in Myopes with Standard and Reversed Contrast Optotypes
Abstract The aim of this study was to assess the visual acuity of myopes with standard and reversed contrast optotypes and to determine how the visual acuity of myopes is affected by optical defocus and the type of optical correction, either contact lenses or spectacles. Twenty-three myopic subjects (18 and 23 years old) with uncorrected vision had their visual acuity assessed with both standard and reversed contrast optotypes. The study also included 10 myopes with contact lens as well as habitual spectacle correction. The visual acuity for myopes with uncorrected vision was better with reversed than standard contrast optotypes. Better reversed contrast than standard contrast visual acuity…
Cilvēka fizioloģijas un uztveres aktuālie pētījumi 2020. gadā
Šajā izdevumā apkopoti LU FMOF Optometrijas un redzes zinātnes nodaļas un tās sadarbības partneru aktuālie pētījumi par cilvēka fizioloģiju un uztveri. 2020. gadā. Pētījumi ir saistīti ar redzes zinātni un klīnisko optometriju. Daļa rakstu ir latviešu, daļa angļu valodā. // This collection of publications consists of research done in Department of Optometry and Vision Science, Faculty of Physics, Mathematics and Optometry, University of Latvia. Reasearch topics are related with vision science and clinical optometry. Some of the articles are in Latvian, some of them are in English.
Cilvēka fizioloģijas un uztveres aktuālie pētījumi 2019.gadā : rakstu krājums
Izdevumā apkopoti LU FMOF Optometrijas un redzes zinātnes nodaļas, kā arī citu struktūrvienību aktuālie pētījumi par cilvēka fizioloģiju un uztveri. 2019. gads Optometrijas un redzes zinātnes nodaļā ir zīmīgs ar nodaļas ilggadējo profesoru jubilejām. Savu apaļo dzimšanas dienu jau ir nosvinējis LU emeritus profesors Ivars Lācis, kurš ir devis lielu ieguldījumu Latvijas Universitātes attīstībā, kā arī viens no Latvijas optometrijas stūrakmeņiem. Šajā izdevumā bez zinātniskiem rakstiem ir īss ieskats viņa biogrāfijā, kura tapusi sadarbībā ar Latvijas Universitātes bibliotēku.
Monocular Versus Binocular Calibrations in Evaluating Fixation Disparity With a Video-Based Eye-Tracker
When measuring fixation disparity (an oculomotor vergence error), the question arises as to whether a monocular or binocular calibration is more precise and physiologically more appropriate. In monocular calibrations, a single eye fixates on a calibration target that is taken as having been projected onto the center of the fovea; the corresponding vergence state represents the heterophoria (the resting vergence position), which has no effect on the calibration procedure. In binocular calibrations, a vergence error may be present and may affect the subsequent measurement of the fixation disparity during binocular recordings. This study includes a test of the precision of both monocular and …
Algorithms for skiascopy measurement automatization
Automatic dynamic infrared retinoscope was developed, which allows to run procedure at a much higher rate. Our system uses a USB image sensor with up to 180 Hz refresh rate equipped with a long focus objective and 850 nm infrared light emitting diode as light source. Two servo motors driven by microprocessor control the rotation of semitransparent mirror and motion of retinoscope chassis. Image of eye pupil reflex is captured via software and analyzed along the horizontal plane. Algorithm for automatic accommodative state analysis is developed based on the intensity changes of the fundus reflex.
Accommodative Amplitude in School-Age Children
Abstract In children, intensive near-work affects the accommodation system of the eye. Younger children, due to anatomical parameters, read at smaller distance than older children and we can expect that the accommodation system of younger can be affected more than that of older children. We wanted to test this hypothesis. Some authors showed that the norms of amplitude of accommodation (AA) developed by Hofstetter (1950) not always could be applied for children. We also wanted to verify these results. A total of 106 (age 7-15) children participated in the study. Distance visual acuity was measured for all children and only data of children with good visual acuity 1.0 or more (dec. units) we…
Perception of Biological Motion in Central and Peripheral Visual Fields
Abstract Studies analysing biological motion perception based on reduced number of dots have demonstrated that biological motion can be perceived even when only the lower part of the body is visible or when the number of dots representing the object is reduced. What is the minimal amount of information that enables biological motion to be distinguished from its scrambled version? The results of the current experiment demonstrate that biological motion can be distinguished from its scrambled version when the object is formed of approximately 5 (4.7 ± 0.1) dots. Additionally, we also investigated whether the threshold value for biological motion perception differs in central and peripheral vi…