Signal Processing in the Outer Retina

Jan 23, 2019 by in OPHTHALMOLOGY Comments Off on Signal Processing in the Outer Retina

Light-evoked hyperpolarizing signals in rods and cones are transmitted to and processed by neurons in the rest of the retina through a complex, but highly organized network of electrical and…

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Photoresponses of Rods and Cones

Jan 23, 2019 by in OPHTHALMOLOGY Comments Off on Photoresponses of Rods and Cones

Retinal rods and cones are highly specialized neurons that respond to light with an electrical signal (see Chapter 18 ) and provide the sensory input for vision. In contrast to…

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The Synaptic Organization of the Retina

Jan 23, 2019 by in OPHTHALMOLOGY Comments Off on The Synaptic Organization of the Retina

The basic architecture, signal flow, and neurochemistry of signaling through the vertebrate retina is well-understood: photoreceptors, bipolar cells (BCs), and ganglion cells (GCs) are all thought to be glutamatergic neurons…

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Light Adaptation in Photoreceptors

Jan 23, 2019 by in OPHTHALMOLOGY Comments Off on Light Adaptation in Photoreceptors

1 Vision from starlight to sunlight The human visual system operates effectively over an enormously wide range of intensities, of at least a billion-fold, from around 10 −4 cd m −2…

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Sensory Innervation of the Eye

Jan 23, 2019 by in OPHTHALMOLOGY Comments Off on Sensory Innervation of the Eye

Introduction The sensory innervation of the eye is provided by the peripheral axons of primary sensory neurons located in the trigeminal ganglion. The sensory nerves enter the eyeball mainly through…

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Biochemical Cascade of Phototransduction

Jan 23, 2019 by in OPHTHALMOLOGY Comments Off on Biochemical Cascade of Phototransduction

Overview Phototransduction is the series of biochemical events that lead from photon capture by a photoreceptor cell to its hyperpolarization and slowing of neurotransmitter release at the synapse. This overall…

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Outward-Directed Transport

Jan 23, 2019 by in OPHTHALMOLOGY Comments Off on Outward-Directed Transport

Introduction In ocular therapeutics, the current literature describes drug delivery limitations posed by outward directed transport mechanisms of the eye. Drug delivery to ocular tissues is restricted by various factors…

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Formation and Function of the Tear Film

Jan 23, 2019 by in OPHTHALMOLOGY Comments Off on Formation and Function of the Tear Film

1 Tear film overview The tear film overlays the ocular surface, which is comprised of the corneal and conjunctival epithelia, and provides the interface between these epithelia and the external…

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Functions of the Orbit and Eyelids

Jan 23, 2019 by in OPHTHALMOLOGY Comments Off on Functions of the Orbit and Eyelids

Introduction The cranium protects the brain and provides scaffolding for facial structures. During primate evolution, the orbits were enlarged and reoriented towards the front of the face. This, along with…

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The Lens

Jan 23, 2019 by in OPHTHALMOLOGY Comments Off on The Lens

The lens is a remarkably specialized epithelial tissue that is responsible for fine-tuning the image that is projected on the retina. To perform this function it must be transparent, have…

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