Drawing by David T. Ramsey, DVM, Diplomate, ACVO
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External photograph of the iridocorneal angle of a Rocky Mountain Horse. Note the anterior displacement of Schwalbe’s line (small arrows) and extensive goniosynechiae (large arrow heads) of the lateral iridocorneal angle. An asterisk marks the flash reflection from the camera.
External photograph of the iridocorneal angle of a Rocky Mountain Horse with a focal goniosynechia. A focal area of peripheral lateral iridocorneal adhesion is present (arrows) with concurrent cornea globosa, congenital miosis, iris stromal hypoplasia, and a hypoplastic and encircling granula iridica (arrow heads). (From Ramsey DT, et al: Congenital ocular abnormalities in Rocky Mountain horses. Comp Ophthalmol 1999;2:47-59, with permission).
Fig angle-4 001.jpg.
Extensive malformation and goniosynechiae of the lateral iridocorneal angle has caused corneal edema in the eye of this Rocky Mountain horse.
Fig cataract OD 001.jpg Fig. cataract OS 001._web.jpg
Oblique profile photograph of the crystalline lens through the pupil of the right (Fig. a) and Left (Fig. b) eyes of a Rocky Mountain horse. Cataract of the nuclear-cortical junction (arrow heads) is evident. Two cysts arising from the lateral aspect of the ciliary body (arrows) are also evident in Figure a.
Fig cyst-1-001.jpg
Oblique profile photograph of the lateral anterior segment of the right eye of a Rocky Mountain horse. Two large, translucent, cysts (arrows) arising from the anterior ciliary body epithelium are evident. Elongated ciliary body processes (white arrow heads) are also evident.
Fig cyst-2-001.jpg
Oblique profile photograph of the lateral anterior segment of the left eye of a Rocky Mountain horse. A large, fluid-filled translucent cyst of the lateral aspect of the ciliary body protrudes into the vitreous body. (arrows).
Oblique profile images of the lateral anterior segment of the right (Fig 4) and left (Fig 3) eyes of a Rocky Mountain horse. Figure 4--Three small cysts and one large translucent cyst (arrowheads) arising from the posterior surface of the anterior ciliary body and peripheral retina are present. (From Ramsey DT, et al: Congenital ocular abnormalities in Rocky Mountain horses. Comp Ophthalmol 1999;2:47-59, with permission ). Fig 3-- A multiloculated cyst arising from the anterior ciliary body is present (arrowheads).
Fig cyst-5-001.jpg
Oblique profile photograph through the pupil of the lateral anterior segment of the right eye of a Rocky Mountain horse. A large, fluid-filled, translucent, cyst of the lateral aspect of the ciliary body is present (arrows).
Fig detach_001.jpg
Detachment of the peripheral part of the lateral retina of the left eye is present in this Rocky Mountain horse (large arrows). Two well-demarcated lines of hyperpigmentation mark the boundary of two previous retinal detachments (small arrowheads).
Fig ectropion cataract 001.jpg
Photograph of the right eye of a Rocky Mountain horse with ectropion uvea, dyscoria, and cataract. The granula iridica is hypoplastic (large arrows) and complete circumferential ectropion uvea is present at the pupillary margin (arrows). The pupil is misshapen.
Fig dysplasia_001.jpg
Retinal dysplasia is characterized by numerous pigmented folds in the superior peripapillary neurosensory retina.
Fig ectropion uvea_001.jpg
Photograph of the right eye of a Rocky Mountain horse with ectropion uvea, dyscoria, cataract, and lens subluxation. The granula iridica is hypoplastic, the pupil is misshapen, and complete circumferential ectropion uvea is present. Nuclear cataract of the nuclear-cortical junction (arrow heads) is present. Vitreous is present in the anterior chamber between the iris and lens (arrow) secondary to posterior ventral lens subluxation.
Fig equine-1 001.jpg
Photograph of a Belgian Draft horse with numerous congenital ocular abnormalities identical to those described in other horse breeds that have the Silver Dapple locus. The coat color is chocolate with dappling and the mane and tail are light flaxen.
Fig equine-2 001.jpg
Photograph of a Shetland Pony with numerous congenital ocular abnormalities identical to those described in other horse breeds that have the Silver Dapple locus. The coat color is chocolate with dappling and the mane and tail are white.
Fig equine-3 001.jpg
Photograph of a Miniature horse with numerous congenital ocular abnormalities identical to those described in other horse breeds that have the Silver Dapple locus. The coat color is chocolate with dappling and the mane and tail are white.
Fig equine-5 001.jpg
Photograph of a Rocky Mountain horse. The coat color is chocolate with dappling and the mane and tail are flaxen chocolate.
Fig equine-6 001.jpg
Photograph of a Rocky Mountain horse with congenital ocular abnormalities identical to those described in other horse breeds that have the Silver Dapple locus. The coat color is red chocolate (sorrel coat with black points) and the mane and tail are white.
Fig xxxoo4 001_web_composite.jpg
Equine xxoo4 001.jpg
Fig equine-7 001.jpg
Photograph of a Rocky Mountain horse with congenital ocular abnormalities identical to those described in other horse breeds that have the Silver Dapple locus. The coat color is chocolate with dappling and the mane and tail are white.
Fig steepcornea-1.jpg and flatcornea-1
Profile photographs of the right cornea of two six-month-old, female, Rocky Mountain horses. Fig a (steepcornea) cornea globosa is characterized by a grossly observable, excessively globular contour of the cornea with atypical protrusion. Fig b (flatcornea) profile photograph of a normal cornea from an age- and gender-matched Rocky Mountain horse. (From Ramsey DT, et al: Congenital ocular abnormalities in Rock Mountain Horses.
Comp Ophthalmol 1999;2:47-59, with permission.)
Enug-cg --1_web.jpg euc_normal_web.jpg
Photographs of the right eye of two age, gender and breed-matched Rocky Mountain horses. Figure a. (enuc-cg 001) Cornea globosa is characterized grossly by excessive anterior protrusion of the cornea. Figure b. (enuc-normal). Photograph of a normal enucleated eye from an age- and gender-matched Rocky Mountain horse.
Fig face-1 001.jpg
Full-face photograph of a Rocky Mountain horse with facial dysmorphism. Note the telecanthus (abnormally increased distance between the eyes) and excessive bony protrusion of the supraorbital space.
Fig Face-2 001.jpg
Telecanthus and exophthalmos (excessive protrusion of the eyes) is present in this Rocky Mountain horse with congenital ocular abnormalities.
Fig globosa-adult 001.jpg
Cornea globosa characterized by excessive anterior protrusion of the cornea, a miotic pupil, and an excessively deep anterior chamber are present in the Rocky Mountain Horse but the plane of the lens-iris diaphragm appears normal.
General-1 001.jpg and General-2 002.jpg.
Serial photographs of the same Rocky Mountain horse stallion taken several years apart. Fig a (General-1) This stallion has a dark chocolate coat color and white mane and tail color. Fig b (General-2) The coat color remained a dark chocolate color but the mane and tail dolor became a flaxen chocolate color as the horse aged. (Photographs courtesy of Jerry Lafayette).
Globosa-foal.jpg Globosafoal2.jpg
Profile photographs of two Rocky Mountain Horses with cornea globosa. Internal reflection of light is evident in both corneas because of substantial cornea globosa.
Figure his-iris-gross
Photomicrograph of the iris of a Rocky Mountain horse with cornea globosa and congenital miosis. The granula iridica are flattened and hypoplastic. The dilator pupillae muscle and iris stroma are also hypoplastic. Note the abnormal ciliary epithelium and primitive neurosensory retinal tissue located along the posterior iris surface. (H & E, X4).
Figure granula-normal.jpg and granula-RMH.jpg
High power photomicrographs of the granula iridica in Fig ?? above and from age- and gender-matched horses. Figure a, (granula.jpg) Note the flattened and hypoplastic granula iridica. (H & E, X 20). Figure b (granulaRMH.jpg). Normal granula iridica from a normal horse (H & E, X 20).
Figure hi water-det 001.jpg
Detachment of the peripheral part of the temporal retina of the right eye is present (arrowhead). A curvilinear pigmented line is present beyond the retinal detachment (arrow) and signifies a demarcation line from a previous retinal detachment (“high-water marker”). (From Ramsey DT, et al: Congenital ocular abnormalities in Rocky Mountain horses. Comp Ophthalmol 1999;2:47-59, with permission ).
Figure hi water8 001.jpg
Multiple, concentric, well-delineated, darkly pigmented curvilinear streaks of retinal pigment epithelium are present in the peripheral part of the tapetal fundus of the right eye of a Rocky Mountain horse. Pigmented streaks originate and terminate at the ora ciliaris retinae and extend toward the optic papilla. Each curvilinear streak signifies a previous demarcation line from previous retinal detachments. (From Ramsey DT, et al: Congenital ocular abnormalities in Rocky Mountain horses. Comp Ophthalmol 1999;2:47-59, with permission ).
Figure hi water001.jpg
Several curvilinear pigmented streaks are present in the right eye of a Rocky Mountain horse. These streaks signify a demarcation line from a previous retinal detachment (“high-water marker”).
Figure Histo-hi water001.jpg
Proliferation of retinal pigment epithelium with disorganization and thinning of the overlying neurosensory retina are evident and correspond topographically with well-delineated curvilinear streaks of pigment observed clinically in Figures xxxx above (H & E, X 50). (From Ramsey DT, et al: Congenital ocular abnormalities in Rocky Mountain Horses. Comp Ophthalmol 1999:2:47-59, with permission.)
Figure Histo-cyst001.jpg
Photomicrograph of a large cyst arising from the nonpigmented ciliary body epithelium of the pars placata. Glial tissue resembling primitive neurosensory retina (arrows) forms the inner cyst wall (H & E, X 10). (From Ramsey DT, et al: Congenital ocular abnormalities in Rocky Mountain horses. Comp Ophthalmol 1999;2:47-59, with permission ).
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Fig. K
Figure Histo2-cyst001.jpg. Photomicrograph of a large cyst arising from the nonpigmented ciliary body epithelium of the pars placata. Glial tissue resembling primitive neurosensory retina (arrows) forms the inner cyst wall (H & E, X 10).
Figure ? a and b. (histo-dysplasia-2.jpg. and histo-dysplasia-1.jpg.)
Photomicrographs of retinal dysplasia from two horses. Figure ?a). Retinal dysplasia is characterized rosette structures in the neurosensory retina of the peripheral tapetal fundus. Hypoplasia and degeneration of the neurosensory retina are characterized by lack of normal sensory retinal architecture with disorganization and thinning of the neurosensory retina and focal proliferation of the retinal pigment epithelium (H & E, X 125). Figure ? b) Disorganization of the outer nuclear layer and rosette formation involving the outer nuclear layer and loss of photoreceptor outer segments are evident (H& E, X 125). (From Ramsey DT, et al: Congenital ocular abnormalities in Rocky Mountain horses. Comp Ophthalmol 1999;2:47-59, with permission ).
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Fig. K
Figure histo-dyspl-papilla001.jpg.
Figure hi water8 001.jpg. Multiple, concentric, well-delineated, darkly pigmented curvilinear streaks of retinal pigment epithelium are present in the peripheral part of the tapetal fundus of the right eye of a Rocky Mountain horse. Pigmented streaks originate and terminate at the ora ciliaris retinae and extend toward the optic papilla. Each curvilinear streak signifies a previous demarcation line from previous retinal detachments. (From Ramsey DT, et al: Congenital ocular abnormalities in Rocky Mountain horses. Comp Ophthalmol 1999;2:47-59, with permission ).
Right photograph--The optical quality of a cornea globosa eye of a foal focused at 5 feet compared with that of a foal with normal optical quality (left photo).
Right photograph--The optical quality of a cornea globosa eye of a foal focused at 25 feet compared with that of a foal with normal optical quality (left photo).
Right photograph--The optical quality of a cornea globosa eye of a foal focused at 300 feet compared with that of a foal with normal optical quality (left photo).
Vision in horses with cornea globosa is poor from the time of birth but improves until approximately 10 months of age. During this period of time, horses with cornea globosa undergo a process called "emmetropization" whereby structures and cavities within the eye are altered to improve the optical quality of vision. After 10 months of age, the optics of the cornea globosa eye is not different from the optics of the normal horse eye.