Foveal

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

Effect of stimulus size, duration, and retinal location upon the appearance of color.

Abstract: The names given to spectral stimuli from 480 to 610 mμ and to a white-light test stimulus were obtained using 11′ or 21′ diam stimulus fields, exposed for 20 msec in the fovea and for 20 and 200 msec at 5° and 10° in the periphery The experiment was designed to test the hypothesis that normal color vision is replaced by tritanopic vision in all parts of the retina if the total luminous energy is sufficiently reduced The results obtained with four observers confirm the presence of tritanopia when small brief stimuli are viewed foveally but fail to confirm it in the periphery Rather, reduced color vision in the periphery is more nearly characteristic of deuteranomaly which ends ultimately in colorless vision These results are discussed as giving support to the notion that foveal tritanopia is due to the depressed sensitivity of the blue receptor mechanism found in the central fovea

Ontogenesis of auditory fovea representation in the inferior colliculus of the Sri Lankan rufous horseshoe bat, Rhinolophus rouxi.

Abstract: This report describes the ontogenesis of tonotopy in the inferior colliculus (IC) of the rufous horseshoe bat (Rhinolophus rouxi) Horseshoe bats are deaf at birth, but consistent tonotopy with a low-to-high frequency gradient from dorsolateral to ventromedial develops from the 2nd up to the 5th week The representation of the auditory fovea is established in ventro-mediocaudal parts of the IC during the 3rd postnatal week (Fig 3) Then, a narrow frequency band 5 kHz in width, comprising 16% of the bat's auditory range, captures 50–60 vol% of the IC (Fig 3c) However, foveal tuning is 10–12 kHz (1/3 octave) lower than in adults; foveal tuning in females (65–68 kHz) is 2–3 kHz higher than in males (62–65 kHz) Thereafter, foveal tuning increases by 1–15 kHz per day up to the 5th postnatal week, when the adult hearing range is established (Figs 4, 5) The increase of sensitivity and of tuning sharpness of single units also follows a low-to-high frequency gradient (Fig 6) Throughout this development the foveal tuning matches the second harmonic of the echolocation pulses vocalised by these young bats The results confirm the hypothesis of developmental shifts in the frequency-place code for the foveal high frequency representation in the IC

Foveal microvascular anomalies on optical coherence tomography angiography and the correlation with foveal thickness and visual acuity in retinopathy of prematurity.

Abstract: To assess foveal microvascular structure and the correlation between foveal retinal thickness and best corrected visual acuity (BCVA) in children with retinopathy of prematurity (ROP). This is a retrospective case-control study. A total 42 eyes in 23 patients with history of anti-vascular endothelial factor (VEGF) agent treatment and 51 eyes of 27 healthy age-matched subjects as the control group were analyzed. Foveal avascular zone (FAZ) and foveal vessel density (VD) were measured by optical coherence tomography angiography (OCT-A). Foveal thickness was measured by cross-sectional OCT. Correlations between FAZ area, foveal VD, foveal thickness, BCVA, gestational age (GA), and birth body weight (BBW) were performed. ROP children had a significantly smaller FAZ area and higher foveal VD, and the foveal thickness was significantly higher as compared to controls (all P < 0.0001). We noted a significant negative correlation between FAZ area and foveal thickness. In addition, a significant positive correlation between foveal VD and foveal thickness was identified. With regard to prematurity status, gestational age and birth body weight were both significantly correlated with FAZ area, foveal VD, and fovea inner retinal thickness. Multivariable analysis showed that thicker inner retinal thickness and higher superficial vascular density were associated with suboptimal visual acuity. By using OCT-A, we identified significant foveal microvascular anomalies in ROP children. The correlation between the microvascular anomalies, central foveal thickness, and suboptimal visual acuity was also noted. Because of the retrospective nature, more studies are necessary to further establish the relationship.