Anterior segment morphology and morphometry in selected reptile species using optical coherence tomography

Rival, Franck; Linsart, A.; Isard, Pierre‐François; Besson, Christian; Dulaurent, Thomas

doi:10.1111/vop.12186

Cited by 14 publications

(5 citation statements)

References 23 publications

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“…In this study, the mean CCT value was 177.6 µm, which was higher than that of a nocturnal leopard gecko, as observed using OCT in the previous study (75 µm) 11 . The CCTs in other diurnal saurian species ranged from 50 to 200 µm 11 .…”

Section: Discussioncontrasting

confidence: 55%

“…The relationship between retinal structure abnormalities and vision‐related diseases including retinal dysplasia, 8 progressive retinal atrophy, 9 sudden acquired retinal degeneration syndrome (SARDS), 10 and glaucoma 3 has been studied in dogs. There are a few studies on reptilian species (saurians, ophidians, and chelonians) 11,12 . However, to our knowledge, those studies only obtained images of the cornea and anterior chamber, and there are no published studies of OCT parameters in the posterior segment of the reptilian eye.…”

Section: Introductionmentioning

confidence: 99%

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Optical coherence tomography of the Tokay gecko (Gekko gecko) eye

Kang

Kwon

et al. 2020

Veterinary Ophthalmology

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Objective To provide images of the anterior and posterior structures of the gecko eye using spectral domain optical coherence tomography (SD‐OCT). Animals and procedures Eight ophthalmologically normal Tokay geckos (Gekko gecko) were used. The nose‐cloaca distance and body weight were measured for each gecko. Tomographic images were obtained using SD‐OCT without the use of anesthetic or mydriatic agents. The central corneal thickness (CCT), the anterior chamber depth (ACD), and the length of the conus papillaris (CP) were manually measured using OCT images. The thickness of the retinal nerve fiber layer (RNFL) around the CP and the retinal thickness in all four quadrants (superior, nasal, inferior, and temporal areas) were automatically measured using the OCT software program. Results The mean values of the nose‐cloaca distance and body weight were 13.8 ± 0.9 cm and 41.3 ± 9.0 g, respectively. The mean values of CCT, ACD, and CP length were 177.6 ± 20.9 µm, 1205.0 ± 79.9 µm, and 1546.4 ± 208.8 µm, respectively. The mean value of RNFL thickness was 52.0 ± 8.2 µm, and the superior region was the thickest. The mean value of total retinal thickness was 202.5 ± 9.4 µm, and the temporal region was the thickest. Conclusions Tomographic images of the anterior and posterior segments of the living gecko eye could be obtained using the OCT unit. Multiple retinal layers and anatomical features of the CP were identified.

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Section: Discussioncontrasting

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Optical coherence tomography of the Tokay gecko (Gekko gecko) eye

Kang

Kwon

et al. 2020

Veterinary Ophthalmology

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“…In all reptiles, the dilated pupil is close to circular (Walls, 1942;Mann, 1931;Werner, 1967), but on illumination pupil shape varies widely. It ranges from circular in all testudines (Mann, 1931;Granda et al, 1995;Rival et al, 2015), some snakes (Mann, 1931;Werner, 1970;Brischoux et al, 2010), and many lizards (Mann, 1931;New et al, 2012), to a narrow vertical slit in many snakes (Mann, 1931;Walls, 1942;Werner, 1967;Brischoux et al, 2010), crocodylians (Mann, 1931;Allen & Neill, 1950;Walls, 1942), and in sphenodontia (Mann, 1931). Horizontally slit pupils are less common in reptiles, but occur, for example, in some tree snakes (Mann, 1931;Heath et al, 1969).…”

Section: Pupil Shapementioning

confidence: 99%

“…An animal whose eye is adapted for vision in low light levels by, for example, the possession of a tapetum lucidum and a retina dominated by sensitive rods, may be compromised in daylight if it relied on a circular pupil. Slit-like pupils among terrestrial species are therefore usually found in predominantly nocturnal animals that nevertheless are sometimes abroad during the day (Walls, 1942;Mann, 1931;Brischoux et al, 2010;Rival et al, 2015;Banks et al, 2015). Strictly diurnal or nocturnal terrestrial animals, on the other hand, tend to have circular pupils, as they would derive less benefit from being able to adapt to a wide range of illumination.…”

Section: Allow a Greater Range Of Aperture Sizesmentioning

confidence: 99%

The pupillary light responses of animals; a review of their distribution, dynamics, mechanisms and functions

Douglas

2018

Progress in Retinal and Eye Research

103

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The timecourse and extent of changes in pupil area in response to light are reviewed in all classes of vertebrate and cephalopods. Although the speed and extent of these responses vary, most species, except the majority of teleost fish, show extensive changes in pupil area related to light exposure. The neuromuscular pathways underlying light-evoked pupil constriction are described and found to be relatively conserved, although the precise autonomic mechanisms differ somewhat between species. In mammals, illumination of only one eye is known to cause constriction in the unilluminated pupil. Such consensual responses occur widely in other animals too, and their function and relation to decussation of the visual pathway is considered. Intrinsic photosensitivity of the iris muscles has long been known in amphibia, but is in fact widespread in other animals. The functions of changes in pupil area are considered. In the majority of species, changes in pupil area serve to balance the conflicting demands of high spatial acuity and increased sensitivity in different light levels. In the few teleosts in which pupil movements occur they do not serve a visual function but play a role in camouflaging the eye of bottom-dwelling species. The occurrence and functions of the light-independent changes in pupil size displayed by many animals are also considered. Finally, the significance of the variations in pupil shape, ranging from circular to various orientations of slits, ovals, and other shapes, is discussed.

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“…Also, snakes have round lenses that move toward and away from the retina to focus [15,28,30] . The present study revealed that the lens of T. mutabilis has a spherical like most of reptilian species [31,32] .…”

Section: Discussionmentioning

confidence: 52%

Adaptation of Eye of the Egyptian Agama "Trapelus Mutabilis" According to Its Activity Pattern

Gadel-Rab

Gaber

Saad

et al. 2023

Egyptian Journal of Zoology

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The present study gives brief discussion about some structure of the eye of the Egyptian agama, Trapelus mutabilis, according to its diurnal activity. One of necessary components of the eye responsible for focusing the light on surface of the retina is the lens and cornea. The Egyptian agama possess spherical lens with a biconvex surface, consists of single layer of simple cuboidal epithelial cells anterior to the subcapsular cavity and capsulated by a thin cellular capsule. The cornea of the Egyptian agama is a transparent thin-walled curved structure that covers front of the eye. Histologically, cornea is formed of five layers: epithelium, bowman's layer, stroma, Descemet's membrane, and endothelium. The inner surface of eyeball is lining by retina, which contains some projections with small pits and a wide single fovea. Retinal layers represented by retinal pigmented layer, photoreceptor layer, cellular layers, and neural one. Photoreceptor layer of retina contains both single and double cones. The conus papillaris is a simple coneshaped projection, heavily pigmented, and originating on top of the optic nerve that protrudes from retina into the vitreous chamber. The surface of conus papillaris has more projections with pits. Histologically, conus papillaris consists of blood vessels and many black pigment granules. The present study concluded that the lens and the transparent cornea with its curved appearance, and the cone photoreceptors only of the eye retina reflecting their adaptation to the diurnal activity pattern of the Egyptian agama.

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Anterior segment morphology and morphometry in selected reptile species using optical coherence tomography

Abstract: Despite grossly similar AS architecture, the three groups of reptiles in the study demonstrated differences that are suggestive of a link between anatomical disparities and variations in environment and lifestyle.

Cited by 14 publications

References 23 publications

Optical coherence tomography of the Tokay gecko (Gekko gecko) eye

Optical coherence tomography of the Tokay gecko (Gekko gecko) eye

The pupillary light responses of animals; a review of their distribution, dynamics, mechanisms and functions

Adaptation of Eye of the Egyptian Agama "Trapelus Mutabilis" According to Its Activity Pattern

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