Ophthalmology

Case report highlights dangers of eyeball tattooing

(HealthDay)—Eyeball tattooing can lead to ocular penetration, intraocular pigment deposition, and associated complications, and public awareness of the risks must increase, according to a letter to the editor published ...

Medical research

Stem cells show potential to treat a leading cause of blindness

(Medical Xpress)—Stem cells derived from body fat show great potential for treating and possibly even reversing the effects of diabetic retinopathy, a complication of diabetes that threatens the vision of millions, new ...

Ophthalmology

Diabetes drug could treat leading cause of blindness

University of Texas Medical Branch at Galveston researchers have discovered that a drug already prescribed to millions of people with diabetes could also have another important use: treating one of the world's leading causes ...

Eye

Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement. In higher organisms the eye is a complex optical system which collects light from the surrounding environment, regulates its intensity through a diaphragm, focuses it through an adjustable assembly of lenses to form an image, converts this image into a set of electrical signals, and transmits these signals to the brain through complex neural pathways that connect the eye via the optic nerve to the visual cortex and other areas of the brain. Eyes with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system. Image-resolving eyes are present in molluscs, chordates and arthropods.

The simplest "eyes", such as those in microorganisms, do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms. From more complex eyes, retinal photosensitive ganglion cells send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to effect circadian adjustment.

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