
What is the History of Medieval Optics Really About?1
... transmitted would cross at centerpoint A and continue on in inverted order. The resulting image would therefore be upside down. But in meeting the refractive interface between glacial and vitreous humors before centerpoint A, these rays are deflected outward by being bent toward the normal as they p ...
... transmitted would cross at centerpoint A and continue on in inverted order. The resulting image would therefore be upside down. But in meeting the refractive interface between glacial and vitreous humors before centerpoint A, these rays are deflected outward by being bent toward the normal as they p ...
to PDF of Visual and Anatomic Outcomes of Vitrectomy
... February 2003 to November 2005, 46% of the 79 eyes with perforating injuries had entrance wounds in the cornea.2 Most corneas retain adequate clarity to perform retinal surgery, but some have severe opacities that preclude the diagnosis and repair of posterior segment pathology. Corneal clarity may ...
... February 2003 to November 2005, 46% of the 79 eyes with perforating injuries had entrance wounds in the cornea.2 Most corneas retain adequate clarity to perform retinal surgery, but some have severe opacities that preclude the diagnosis and repair of posterior segment pathology. Corneal clarity may ...
Experimental porcine models of retinal ischemia
... inner wall of the primitive optic cup (Figure 1). A tenth layer, the pigment epithelium layer (RPE), lies just outside these layers, and is so closely associated with them in structure and function, that it can be considered part of the retina, although it has a different origin. The light-sensitive ...
... inner wall of the primitive optic cup (Figure 1). A tenth layer, the pigment epithelium layer (RPE), lies just outside these layers, and is so closely associated with them in structure and function, that it can be considered part of the retina, although it has a different origin. The light-sensitive ...
Patient-specific induced pluripotent stem cells (iPSCs) for the study
... Leber congenital amaurosis, as well as the more complex and heterogeneous disease, age-related macular degeneration (AMD), are collectively the leading cause of incurable blindness in the developed world (Huang et al., 2011). For years, ophthalmologists and vision scientists have dreamed of restorin ...
... Leber congenital amaurosis, as well as the more complex and heterogeneous disease, age-related macular degeneration (AMD), are collectively the leading cause of incurable blindness in the developed world (Huang et al., 2011). For years, ophthalmologists and vision scientists have dreamed of restorin ...
Central retinal vein occlusion as an uncommon complication of
... involvement high-dose systemic and local prednisolone was instituted and the eye lesions diminished within days ( figure 1B). ...
... involvement high-dose systemic and local prednisolone was instituted and the eye lesions diminished within days ( figure 1B). ...
The prenatal development of the optic fissure in
... At the 12th gestational day, although the fissure margins approached each other, they only become apposed in posterior levels. Late on the 12th day and especially on the 13th day, small foci of basement membrane apposition were seen in the area of the developing papilla (Fig. 6). However, no evidenc ...
... At the 12th gestational day, although the fissure margins approached each other, they only become apposed in posterior levels. Late on the 12th day and especially on the 13th day, small foci of basement membrane apposition were seen in the area of the developing papilla (Fig. 6). However, no evidenc ...
The Parasympathetic Pathways to Internal Eye Muscles
... continues to do so up to 1,000 Hz. The differing frequency optima for accommodation and pupil constriction are shown in Fig. 1. Does the large difference between the frequency optima for stimulating accommodation and pupil constriction imply a difference in physiology of the ciliary and sphincter ir ...
... continues to do so up to 1,000 Hz. The differing frequency optima for accommodation and pupil constriction are shown in Fig. 1. Does the large difference between the frequency optima for stimulating accommodation and pupil constriction imply a difference in physiology of the ciliary and sphincter ir ...
zeaxantina - A Fórmula
... photoreceptor death within the macula. Increased risk of AMD may result from low levels of lutein and zeaxanthin (macular pigment) in the diet, serum or retina, and excessive exposure to blue light. Through its light-screening capacity and antioxidant activity, macular pigment may reduce photooxidat ...
... photoreceptor death within the macula. Increased risk of AMD may result from low levels of lutein and zeaxanthin (macular pigment) in the diet, serum or retina, and excessive exposure to blue light. Through its light-screening capacity and antioxidant activity, macular pigment may reduce photooxidat ...
Title: Difference in retinal nerve fiber layer thickness between normal
... Background: Screening of the retinal nerve fiber layer (RNFL) is valuable in the early stages of glaucoma, because RNFL changes may precede functional loss. Aim to study: The purpose of this study was to assess the RNFL thickness in normal and glaucomatous eyes. Difference in the RNFL thickness was ...
... Background: Screening of the retinal nerve fiber layer (RNFL) is valuable in the early stages of glaucoma, because RNFL changes may precede functional loss. Aim to study: The purpose of this study was to assess the RNFL thickness in normal and glaucomatous eyes. Difference in the RNFL thickness was ...
EVERYTHING THERAPEUTIC: SAN ANTONIO
... a. Definitions i. An imaging technique that uses a bandpass filter from 535 to 580 nm for excitation and a bandpass filter of 615 nm to 715 nm as a barrier filter to image lipofuscin distribution in the RPE b. Normal fundus autofluorescence i. Uniformity of autofluorescense (isoautofluorescence) thr ...
... a. Definitions i. An imaging technique that uses a bandpass filter from 535 to 580 nm for excitation and a bandpass filter of 615 nm to 715 nm as a barrier filter to image lipofuscin distribution in the RPE b. Normal fundus autofluorescence i. Uniformity of autofluorescense (isoautofluorescence) thr ...
Lipid keratopathy in a rabbit
... rabbits rabbit = FH model). The latter have only few LDL receptors, which results in an ...
... rabbits rabbit = FH model). The latter have only few LDL receptors, which results in an ...
Can we make enemy soldiers blind using lasers?
... Also, it is not "laser" light that may be dangerous. It iis any light li ht off certain t i power, and ...
... Also, it is not "laser" light that may be dangerous. It iis any light li ht off certain t i power, and ...
Role of cyclic AMP in the eye with glaucoma
... that sAC-mediated increasing of the cAMP level can lower IOP (67). Previous studies revealed that sAC contributes to the regulation of conventional outflow (68). In these studies, Bestropin 2 (Best2), an anion channel, was characterized as a bicarbonate channel (69), and Best2 was present only in th ...
... that sAC-mediated increasing of the cAMP level can lower IOP (67). Previous studies revealed that sAC contributes to the regulation of conventional outflow (68). In these studies, Bestropin 2 (Best2), an anion channel, was characterized as a bicarbonate channel (69), and Best2 was present only in th ...
retinal vessel analyzer (rva) - design and function
... An essential part of the RVA is the fundus camera (FF450, Zeiss Jena, Germany). This optical instrument enables the examination of the background area of the eye. It incorporates two optical pathways, the illumination pathway and the observation pathway. Both of them use the (dilated) pupil as an en ...
... An essential part of the RVA is the fundus camera (FF450, Zeiss Jena, Germany). This optical instrument enables the examination of the background area of the eye. It incorporates two optical pathways, the illumination pathway and the observation pathway. Both of them use the (dilated) pupil as an en ...
optic disc abnormalities – diagnosis, evolution and influence on
... with optic disc is primitive epithelial papilla. At or about the mm stage, nerve fibers’ grow from the retinal ganglion cells thought the primitive epithelial papilla into the optic stalk, and the optic nerve is thus formed (). Congenital abnormalities of the optic disc are not so rare. The etio ...
... with optic disc is primitive epithelial papilla. At or about the mm stage, nerve fibers’ grow from the retinal ganglion cells thought the primitive epithelial papilla into the optic stalk, and the optic nerve is thus formed (). Congenital abnormalities of the optic disc are not so rare. The etio ...
Title: An uncharacteristic case of central serous chorioretinopathy
... Uncorrected VA OD 20/60-, OS 20/25Ishihara color vision test, confrontation visual fields, ocular motility, and pupil responses all normal. Facial amsler reveals the entire face of the examiner appears darker when viewing OD versus OS. Refraction : OD Plano-0.50x140 20/50OS -0.25-1.00x075 20/20 -Phy ...
... Uncorrected VA OD 20/60-, OS 20/25Ishihara color vision test, confrontation visual fields, ocular motility, and pupil responses all normal. Facial amsler reveals the entire face of the examiner appears darker when viewing OD versus OS. Refraction : OD Plano-0.50x140 20/50OS -0.25-1.00x075 20/20 -Phy ...
How do external factors influence behaviour and mental
... the eye. However, in a place where there is bright light, such as at the beach on a clear summer day, the pupil contracts and becomes smaller to restrict the amount of light entering the eye. In a place where it is extremely bright, the pupil may be no larger than a pinhead. When it is extremely dar ...
... the eye. However, in a place where there is bright light, such as at the beach on a clear summer day, the pupil contracts and becomes smaller to restrict the amount of light entering the eye. In a place where it is extremely bright, the pupil may be no larger than a pinhead. When it is extremely dar ...
Noninvasive Visualization and Analysis of Parafoveal Capillaries in
... variation.2 The FAZ has been well characterized and is of important clinical significance in a number of different diseases, including diabetes.3 There are two key challenges that must be addressed when performing optical imaging of the retinal microcirculation: low capillary contrast and aberration ...
... variation.2 The FAZ has been well characterized and is of important clinical significance in a number of different diseases, including diabetes.3 There are two key challenges that must be addressed when performing optical imaging of the retinal microcirculation: low capillary contrast and aberration ...
Doppler ultrasonography of the pectinis oculi artery in harpy eagles
... higher metabolism than ciliary body (Gellat-Nicholson et al., 1999). RI values of the long posterior ciliary artery (LPCA) have been demonstrated in the rabbit and the dog as a means to evaluate the importance of the LPCA as a vascular supply to the retina, which is a very highly metabolic tissue (G ...
... higher metabolism than ciliary body (Gellat-Nicholson et al., 1999). RI values of the long posterior ciliary artery (LPCA) have been demonstrated in the rabbit and the dog as a means to evaluate the importance of the LPCA as a vascular supply to the retina, which is a very highly metabolic tissue (G ...
had greater axial lengths than their normal fellow eyes
... that this must be so, and indeed it may be that such an increase is not as central to the disease as implied in the editorial:2 there is a danger here of throwing the baby out with the bathwater. It is well known that glutamate is an amino acid that is abundant in all cells and that it is intimately ...
... that this must be so, and indeed it may be that such an increase is not as central to the disease as implied in the editorial:2 there is a danger here of throwing the baby out with the bathwater. It is well known that glutamate is an amino acid that is abundant in all cells and that it is intimately ...
Prevention and treatment of age‐related macular degeneration
... 1). Focal collections of lipid material are seen as ‘drusen’ on examination of the retina and morphological alteration of the RPE causes hyper- and hypopigmentation (see Figure 2). These changes form part prescriber.co.uk ...
... 1). Focal collections of lipid material are seen as ‘drusen’ on examination of the retina and morphological alteration of the RPE causes hyper- and hypopigmentation (see Figure 2). These changes form part prescriber.co.uk ...
Cell-mediated immunity against human retinal extract, S
... control from Sierra Leone, West Africa. No relationship could be found, however, between the level of antibodies against the retinal proteins tested and the occurrence of onchocercal chorioretinopathy.3 The role of cell-mediated immunity against retinal antigens in ocular onchocerciasis is not yet k ...
... control from Sierra Leone, West Africa. No relationship could be found, however, between the level of antibodies against the retinal proteins tested and the occurrence of onchocercal chorioretinopathy.3 The role of cell-mediated immunity against retinal antigens in ocular onchocerciasis is not yet k ...
Mechanism of Aqueous Humor Secretion, Its Regulation
... The principal function of the eye is to receive the light signal from the environment and transmit it to the brain to create vision. This requires that the structures of the eye involved in light transmission, such as the cornea and the lens, must be transparent. Unlike other tissues of the body, nu ...
... The principal function of the eye is to receive the light signal from the environment and transmit it to the brain to create vision. This requires that the structures of the eye involved in light transmission, such as the cornea and the lens, must be transparent. Unlike other tissues of the body, nu ...
Focal electroretinogram and visual field defect in
... acuity, white dots at the level of retinal pigment epithelium (RPE), scotoma, including enlargement of the blind spot, and visual return without treatment.I2 Although electrophysiological data, such as reduced a-wave in electroretinogram (ERG) and reduced early receptor potential,2 indicate that the ...
... acuity, white dots at the level of retinal pigment epithelium (RPE), scotoma, including enlargement of the blind spot, and visual return without treatment.I2 Although electrophysiological data, such as reduced a-wave in electroretinogram (ERG) and reduced early receptor potential,2 indicate that the ...
Retinal Vascular Disease
... and anemia. A study, based on 363 patients who had temporal artery biopsy, showed that systemic symptoms showing a significant association with a positive temporal artery biopsy for GCA were jaw claudication (odds 9.0 times, p < 0.0001), neck pain (odds ...
... and anemia. A study, based on 363 patients who had temporal artery biopsy, showed that systemic symptoms showing a significant association with a positive temporal artery biopsy for GCA were jaw claudication (odds 9.0 times, p < 0.0001), neck pain (odds ...
Retina

The retina (/ˈrɛtɪnə/ RET-i-nə, pl. retinae, /ˈrɛtiniː/; from Latin rēte, meaning ""net"") is the third and inner coat of the eye which is a light-sensitive layer of tissue. The optics of the eye create an image of the visual world on the retina (through the cornea and lens), which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical events that ultimately trigger nerve impulses. These are sent to various visual centres of the brain through the fibres of the optic nerve.In vertebrate embryonic development, the retina and the optic nerve originate as outgrowths of the developing brain, so the retina is considered part of the central nervous system (CNS) and is actually brain tissue. It is the only part of the CNS that can be visualized non-invasively.The retina is a layered structure with several layers of neurons interconnected by synapses. The only neurons that are directly sensitive to light are the photoreceptor cells. These are mainly of two types: the rods and cones. Rods function mainly in dim light and provide black-and-white vision, while cones support daytime vision and the perception of colour. A third, much rarer type of photoreceptor, the intrinsically photosensitive ganglion cell, is important for reflexive responses to bright daylight.Neural signals from the rods and cones undergo processing by other neurons of the retina. The output takes the form of action potentials in retinal ganglion cells whose axons form the optic nerve. Several important features of visual perception can be traced to the retinal encoding and processing of light.