Foveal

About: Foveal is a research topic. Over the lifetime, 2652 publications have been published within this topic receiving 94120 citations.

Understanding clinically undetected macular changes in early retinopathy of prematurity on spectral domain optical coherence tomography.

Abstract: PURPOSE To investigate macular changes in acute retinopathy of prematurity (ROP). METHODS Fifty-four premature infants with ROP and 20 controls underwent routine ROP screening with indirect ophthalmoscopy and imaging. A tabletop spectral domain optical coherence tomography (SD-OCT) scanner (Spectralis; Heidelberg Engineering, Heidelberg, Germany) was converted into a handheld device to image infants in the office sans sedation. RESULTS SD-OCT images were obtained in all infants in the office. On SD-OCT, 23 of 79 eyes (29.1%) with stage 2 ROP showed abnormal foveal changes despite clinically normal foveae. Of the 23 eyes, 2 distinct patterns of foveal involvement were observed: "pattern A," which was characterized by dome-shaped foveal elevation and cystoid spaces with highly reflective intervening vertical septae, and "pattern B," which was characterized by preservation of the foveal depression with fewer intraretinal cystoid spaces. These patterns were seen in 12 (52.2%) and 11 (47.8%) eyes, respectively. All eyes (100%) belonging to stage 1 ROP (27) and the normal group (40) had no abnormal SD-OCT changes. The mean central foveal thickness was 156.9 ± 28.3 μm, 206.5 ± 98.7 μm, and 135.9 ± 17.6 μm for stage 1, 2, and normal eyes, respectively (P < 0.001). Nineteen of the 23 eyes underwent serial imaging at 52 weeks' postmenstrual age (PMA), and all of them revealed normalization of foveal contours at this visit. CONCLUSIONS SD-OCT changes of the macula in mild ROP have not been previously described. Our method reveals that infants may be imaged supine and unanesthetized in the office. We hypothesize that these transient foveal changes at the critical time of fovealization in premature infants may influence their visual acuity in the adult life.

Trans-saccadic integration of peripheral and foveal feature information is close to optimal.

Abstract: Due to the inhomogenous visual representation across the visual field, humans use peripheral vision to select objects of interest and foveate them by saccadic eye movements for further scrutiny. Thus, there is usually peripheral information available before and foveal information after a saccade. In this study we investigated the integration of information across saccades. We measured reliabilities--i.e., the inverse of variance-separately in a presaccadic peripheral and a postsaccadic foveal orientation--discrimination task. From this, we predicted trans-saccadic performance and compared it to observed values. We show that the integration of incongruent peripheral and foveal information is biased according to their relative reliabilities and that the reliability of the trans-saccadic information equals the sum of the peripheral and foveal reliabilities. Both results are consistent with and indistinguishable from statistically optimal integration according to the maximum-likelihood principle. Additionally, we tracked the gathering of information around the time of the saccade with high temporal precision by using a reverse correlation method. Information gathering starts to decline between 100 and 50 ms before saccade onset and recovers immediately after saccade offset. Altogether, these findings show that the human visual system can effectively use peripheral and foveal information about object features and that visual perception does not simply correspond to disconnected snapshots during each fixation.

The effect of a central task on luminance thresholds for peripherally presented stimuli.

Abstract: The effect of a central task on peripheral vision was investigated by obtaining luminance thresholds for stimuli presented from 20° to 90° in the periphery. A control group observed a steady foveal...