Although the spatial and temporal properties of rod-mediated vision have been extensively characterized, little is known about scotopic motion perception. To provide such information, we determined thresholds for the detection and identification of the direction of motion of sinusoidal grating patches moving at speeds from 1 to 32 deg/s, under scotopic light levels, in four different types of o...

Plants monitor changes in the ambient light environment using sensory photoreceptor families: the phototropins and cryptochromes, which absorb UV-A or blue light; the phytochromes, which sense red/far-red light; and the UV-B photoreceptors, which have not yet been identified. Recent advances suggest that photoreceptor-induced signalling cascades regulate light-modulated gene expression. These r...

Two patients developed traumatic orbital haemorrhage resulting in prolonged blindness. Orbital decompression successfully reversed the visual loss, though both eyes had no light perception for at least 3 1/2 hours. The clinical findings suggest damage to the posterior optic nerve as cause of the visual loss. The optic nerve tolerance time to ischaemic injury may be longer than previously thought.

Larval zebrafish lacking eyes and pineal organ show elevated activity levels and undirected light-seeking behaviour upon loss of illumination. This behaviour, termed dark photokinesis, is mediated by hypothalamic deep brain photoreceptors expressing melanopsin.

We have recently identified cytokinin as an important xylem-carried signal involved in the photosynthetic acclimation of plants to light gradients in dense canopies. Lower leaves become shaded in a dense canopy and consequently have reduced transpiration rates. our measurements have shown that this results in a reduced delivery of cytokinins carried in the transpiration stream to shaded leaves,...

Centipedes are a very old lineage of terrestrial animals. The first completely sequenced myriapod genome reveals that the blind centipede Strigamia maritima has no gene for light-sensory proteins, lacks the canonical circadian clock and possesses unusual features related to chemosensory perception.

Temporal arteritis is a common cause of blindness. Prompt steroid treatment limits unilateral visual loss while protecting the contralateral eye. Established blindness is irreversible. We report a case of temporal arteritis in which an eye with no light perception secondary to an arteritic anterior ischaemic optic neuropathy regained 6/6 vision.

When lifting an object, the brain uses visual cues and an internal object representation to predict its weight and scale fingertip forces accordingly. Once available, tactile information is rapidly integrated to update the weight prediction and refine the internal object representation. If visual cues cannot be used to predict weight, force planning relies on implicit knowledge acquired from re...

We studied 187 patients attending special educational institutions in Saudi Arabia who were blind before the age of 14. All patients underwent complete ophthalmological evaluation. The visual acuity in 31% of the patients was no light perception and in 58% light perception to counting fingers at 3 feet (1 m). 70% were blind before age 2. Prior to 1962 acquired diseases led to blindness in 75% o...

Blue light can damage retina and cause age related macular degeneration. After cataract surgery and lens removal retina stays unprotected. Blue light filtering intraocular lenses (IOL) increase protection of the retina. In our prospective study we investigated clinical results after bilateral implantation of Acrysof Natural IOL to 30 patients (N = 60 eyes). In a control group (N = 60 eyes, 30 p...