SAOphthalmicAtlas&Guide

Preface, x

List of abbreviations, xi

Glossary, xii

Section I  Atlas, 1

1  Orbit, 3

Clinical signs associated with orbital neoplasia, 3 Clinical signs associated with orbital cellulitis, 3 Enophthalmos, 4

Brachycephalic ocular syndrome, 4

Ventromedial entropion associated with brachycephalic ocular syndrome, 4

Clinical signs associated with Horner’s syndrome, 5 Clinical signs associated with Horner’s syndrome, 5 Appearance of Horner’s syndrome following application of

sympathomimetic drugs, 5

Clinical signs associated with orbital neoplasia, 6 Clinical signs associated with proptosis, 6

2  Eyelids, 7

Normal appearance of punctum, 7 Ectopic cilia, 7

Distichiae, 8

Distichiae, 8

Ectopic cilia and chalazion, 8

Lower eyelid entropion due to conformation, 9 Facial trichiasis, 9

Eyelid agenesis, 9

Appearance of entropion after temporary correction using tacking sutures, 10

Lower eyelid ectropion, 10 Meibomian adenoma, 10 Meibomian adenoma, 11 Eyelid melanocytoma, 11 Chalazion, 11

Blepharitis, 12

Blepharitis, 12

Blepharitis, 12

3  Third eyelid, nasolacrimal system, and precorneal tear film, 13

Pathologic changes to the third eyelid associated with pannus, 13

Scrolled third eyelid cartilage, 13

Prolapsed third eyelid gland (“cherry eye”), 14 Prolapsed third eyelid gland (“cherry eye”), 14 Superficial neoplasia of the third eyelid, 14 Neoplasia of the third eyelid gland, 15 Positive Jones test – appearance of fluorescein

in mouth, 15

Positive Jones test – appearance of fluorescein at nostril, 15

4  Conjunctiva, 16

Normal appearance of the conjunctiva, 16 Conjunctival hyperemia, 16

Chemosis and conjunctival hyperemia, 17 Chemosis, 17

Conjunctival follicles, 17

Conjunctival thickening associated with infiltrative neoplasia, 18

Superficial conjunctival neoplasia, 18 Subconjunctival hemorrhage, 18 Conjunctival follicles, 19

Superficial conjunctival neoplasia, 19 Conjunctival neoplasia, 19

5  Cornea, 20

Superficial corneal vascularization associated with keratoconjunctivitis sicca, 20

Appearance of a dry cornea with concurrent anterior uveitis, 20

Typical appearance of superficial corneal vessels, 21 Typical appearance of deep corneal vessels, 21 Typical appearance of corneal edema, 21

Corneal melanosis, 22

Typical melanin distribution associated with pigmentary keratitis, 22

Typical appearance of corneal fibrosis with concurrent corneal vascularization, 22

Corneal white cell infiltrate with concurrent corneal vascularization and edema, 23

Corneal deposits associated with corneal dystrophy, 23 Corneal deposits associated with corneal dystrophy, 23 Corneal mineral deposits, 24

Typical changes associated with keratoconjunctivitis sicca, 24

viii      Contents

Predominantly melanotic corneal changes associated with pannus, 24

Predominantly fibrovascular corneal changes associated with pannus, 25

Corneal changes associated with pannus, mixture of melanosis and fibrovascular changes, 25

Superficial corneal ulcer, 25

Indolent corneal ulcer with fluorescein stain applied, 26 Indolent corneal ulcer prior to fluorescein stain, 26 Indolent corneal ulcer after fluorescein stain, 26

Deep corneal ulcer, 27

Descemetocele after application of fluorescein stain, 27 Descemetocele after application of fluorescein stain,

viewed with cobalt blue light, 27 Corneal perforation with iris prolapse, 28

Corneal perforation with iris prolapse and hyphema, 28 Corneal perforation with large iris prolapse, 28 Melting corneal ulcer, 29

Perforated melting corneal ulcer, 29 Dendritic corneal ulcers, 29 Eosinophilic keratoconjunctivitis, 30 Eosinophilic keratoconjunctivitis, 30 Eosinophilic keratoconjunctivitis, 30

Corneal sequestrum; light brown, with minimal keratitis, 31

Corneal sequestrum; dark brown, with moderate keratoconjunctivitis, 31

Corneal sequestrum; dark brown, with significant keratoconjunctivitis, 31

6  Anterior uvea, 32

Iris-to-cornea persistent pupillary membranes, 32 Iris-to-iris persistent pupillary membranes, 32 Posterior synechiae, 33

Anterior chamber uveal cysts, 33 Anterior chamber uveal cysts, 33

Transillumination of posterior chamber uveal cysts, 34 Iris atrophy, 34

Iris atrophy, 34 Severe iris atrophy, 35

Focal iris hyperpigmentation, 35 Feline diffuse iris melanoma, 35 Feline diffuse iris melanoma, 36 Canine melanocytoma, 36 Canine melanocytoma, 36 Canine ciliary body adenoma, 37

Clinical signs of uveitis: chemosis, episcleral congestion, deep corneal vascularization, and diffuse corneal edema, 37

Aqueous flare, 37 Keratic precipitates, 38

Hypopyon with concurrent corneal ulceration, 38 Hyphema, 38

Rubeosis iridis, 39 Iris thickening, 39

Posterior synechia, 39

Iris bombé, 40

7  Lens, 41

Nuclear sclerosis, 41 Nuclear sclerosis, 41 Incipient cataract, 42 Incipient cataract, 42 Incomplete cataract, 42 Incomplete cataract, 43 Incomplete cataract, 43 Complete cataract, 43

Complete, resorbing cataract, 44 Incomplete resorbing cataract, 44 Lens subluxation, 44

Lens subluxation, 45 Anterior lens luxation, 45 Posterior lens luxation, 45

8  Posterior segment, 46 Normal canine fundus, 46 Normal canine fundus, 46 Normal feline fundus, 47

Subalbinotic, atapetal canine fundus, 47 Subalbinotic feline fundus, 47

Tapetal hyperreflectivity and retinal vascular attenuation in a cat, 48

Tapetal hyperreflectivity and retinal vascular attenuation in a dog, 48

Focal retinal degeneration/chorioretinal scar, 48 Focal retinal degeneration/chorioretinal scar, 49 Tapetal hyporeflectivity due to hypertensive

retinopathy, 49

Tapetal hyporeflectivity, 49 Tapetal hyporeflectivity, 50

Fluid and white cell infiltrate in the nontapetal fundus (chorioretinitis), 50

Focal white cell infiltrate (chorioretinitis) and retinal degeneration in the nontapetal fundus, 50

Multifocal retinal degeneration in the nontapetal fundus, 51

Hemorrhage in the nontapetal fundus, 51 Hemorrhage in the tapetal fundus, 51

Serous retinal detachment and retinal hemorrhage due to hypertensive retinopathy, 52

External view of serous retinal detachment, 52 Serous retinal detachment, 52 Rhegmatogenous retinal detachment, 53 Optic nerve atrophy/degeneration - mild, 53 Optic nerve atrophy/degeneration - severe, 53 Optic disc cupping in an atapetal fundus, 54 Optic disc cupping, 54

Optic neuritis, 54 Optic neuritis, 55 Asteroid hyalosis, 55

Choroidal hypoplasia (collie eye anomaly), 55 Posterior polar coloboma and choroidal hypoplasia

(collie eye anomaly) in a subalbinotic fundus, 56

9  Glaucoma, 57

Typical appearance of acute glaucoma, 57 Haab’s striae, 57

Section II  Guide, 59

10  Orbit, 61

Diseases of the orbit, 62

Brachycephalic ocular syndrome, 62 Horner’s syndrome, 63

Orbital cellulitis and abscess, 65 Orbital neoplasia, 67 Proptosis, 68

Further reading, 70 References, 70

11  Eyelids, 71

Diseases of the eyelid, 72

Distichiasis, 72 Ectopic cilia, 73 Trichiasis, 73 Eyelid agenesis, 75 Entropion, 75 Ectropion, 77 Eyelid neoplasia, 78 Chalazion, 79 Blepharitis, 80 Eyelid laceration, 81 Further reading, 82 References, 82

12  The third eyelid, nasolacrimal system, and precorneal tear film, 83

Diseases of the third eyelid and lacrimal system, 84

Third eyelid gland prolapse (“cherry eye”), 84 Third eyelid neoplasia, 85

Nasolacrimal duct obstruction, 87 Tear film disorders—KCS, 88 Qualitative tear film abnormality, 88 References, 90

13  Conjunctiva, 91

Diseases of conjunctiva, 91

Canine conjunctivitis, 91 Feline conjunctivitis, 93 Conjunctival neoplasia, 95 Further reading, 96 References, 97

14  Cornea, 98 Corneal diseases, 99

Corneal dystrophy, 99

Contents  ix   

Canine keratitis, 100

Keratoconjunctivitis sicca (KCS), 101

Pigmentary keratitis, 103

Pannus/chronic superficial keratitis, 104

Corneal ulceration, 105

Simple corneal ulceration, 105

Indolent corneal ulceration, 106

Deep and perforating corneal ulceration, 108

Melting corneal ulceration, 110

Feline keratitis, nonulcerative and ulcerative, 111

Feline eosinophilic keratoconjunctivitis (EK), 112

Corneal sequestrum, 113

Further reading, 114

References, 114

15  Anterior uvea, 116 Anterior uveal diseases, 116

Persistent pupillary membranes (PPMs), 116 Uveal cysts, 117

Iris atrophy, 118

Feline diffuse iris melanoma, 118

Canine anterior uveal melanocytic neoplasia, 119 Iridociliary neoplasia, 120

Anterior uveitis, 121 Further reading, 124 References, 124

16  Lens, 125

Diseases of the lens, 125

Nuclear sclerosis, 125 Cataract, 126

Lens subluxation and luxation, 128 Further reading, 129

References, 130

17  Posterior segment, 131

Diseases of the posterior segment, 133

Asteroid hyalosis, 133 Collie eye anomaly, 133

Progressive retinal atrophy (PRA), 134

Sudden acquired retinal degeneration syndrome (SARDS), 135

Retinal degeneration (excluding PRA and SARDS), 136 Chorioretinitis, 137

Retinal detachment, 138 Hypertensive retinopathy, 140 Optic neuritis, 141

Further reading, 142 References, 142

18  Glaucoma, 144

Glaucoma, 144 Further reading, 148 References, 148

Index, 149

Small animal general practice is a high-paced profession that requires the veterinarian to arrive at a diagnosis and formulate diagnostic and therapeutic plans within a 15to 20-minute appointment window. As a general practitioner, I often found myself in this position. When I did, I wished for a reference where I could find a photograph similar to what I observed in the patient, along with enough information to implement a plan for treatment. Such scenarios provided the idea for this book. The Small Animal Ophthalmic Atlas and Guide is designed as a handy reference for the busy general practitioner. The book’s goals are to (i) provide an extensive collection of images that practitioners can use to obtain a diagnosis during an outpatient appointment, and (ii) provide just enough information about each disease, relevant diagnostic tests, and treatment to allow for development of a medically sound management plan.

The majority of ophthalmic conditions selected for inclusion in this book are those that present frequently in general practice. A smaller number of less common conditions are also included because of their significant impact on vision and/or overall health of the eye. The purpose of this book is not to describe every known small animal ophthalmic disease, nor is it intended

to be an exhaustive review of the diseases included in the book. Because this is intended to be a quick reference, each chapter includes only enough background information to facilitate discussion of each ocular disease, most of the information is designed to support immediate management, and only select procedures are detailed step-by-step. (For example, detailed directions for ocular surgeries should be sought from other texts.) As a guide for those who wish to delve more deeply into specific ophthalmic conditions, each chapter contains a list of suggestions for further reading.

Of course, no reference book can be a substitute for up-to-date education, sound clinical judgment, and the practitioner’s individual knowledge of a particular patient. Readers of this book should always think critically about the cases presenting to them, seek advice from and make referrals to veterinary ophthalmologists when expert care is warranted, and verify that new research or information from manufacturers has not eclipsed the information in this text. My hope is that this book will make it easier for practitioners to handle ophthalmic cases in their daily practice.

Christine C. Lim

Accommodation—the process by which the eye changes its focus (e.g., from near objects to far objects, or vice versa).

Anisocoria—unequal pupil size between eyes. Anterior uvea—iris and ciliary body.

Anterior uveitis—inflammation of the iris and ciliary body.

Aphakic crescent—this describes the crescent-shaped area of pupil that is visible when the lens is subluxated or luxated. It is an area of pupil that no longer has a lens in it (due to the dislocation). The borders of the aphakic crescent are the pupillary margin and the equator of the lens.

Blepharitis—inflammation of the eyelids. Blepharospasm—squinting. This is due to spasm of the orbicularis

oculi muscle. Marked blepharospasm can cause the eyelids to roll inward (referred to as entropion).

Blood-aqueous barrier—tight junctions within the anterior uvea, which limit the entrance of blood-borne substances into the eye. For example, systemically administered ­medications may not penetrate into the eye when the blood-aqueous barrier is intact. In the presence of uveitis, the blood-aqueous ­barrier is compromised. In addition to the blood-aqueous barrier anteriorly, and the blood-retina barrier functions similarly posteriorly.

Brachycephalic ocular syndrome—a set of conformational abnormalities most commonly seen in brachycephalic dogs. These abnormalities include bilateral exophthalmos, bilateral macropalpebral fissure, and bilateral medial trichiasis.

Buphthalmos—enlargement of the eye as a result of increased intra­ ocular pressure.

Cataract—an opacity of the lens. The size of the opacity can range from small and focal to encompassing the entire lens.

Chalazion—retention of inspissated Meibomian gland secretions within the eyelid, usually accompanied by eyelid inflammation.

Chemosis—edema of the conjunctiva.

“Cherry eye”—this term is used to describe prolapse of the gland of the third eyelid.

Chorioretinitis—inflammation of the choroid and retina, also referred to as posterior uveitis.

Choroid—the posterior portion of the vascular tunic of the eye, also known as the posterior uvea.

Ciliary body—a portion of the anterior uvea. The ciliary body is not visible on ophthalmic examination because it is posterior to the iris. Functions of the ciliary body include aqueous humor production and accommodation, and it also forms a part of the blood-aqueous barrier.

Coloboma—congenital absence of tissue. For example, an optic nerve coloboma refers to an area of the optic nerve where it is missing tissue.

Conjunctivitis—inflammation of the conjunctiva. Cyclitis—inflammation of the ciliary body. Cyclophotocoagulation—destruction of the ciliary body with laser

energy. This procedure is performed in patients with glaucoma. The goal of this procedure is to decrease aqueous humor production (thereby lowering intraocular pressure).

Cycloplegia—paralysis of the ciliary body. Dacryocystitis—inflammation of the nasolacrimal canaliculi and lac-

rimal sac, usually due to nasolacrimal duct obstruction. Distichia—an aberrant hair that arises from a Meibomian gland and

emerges from the Meibomian gland openings. Dyscoria—abnormal shape of the pupil.

Ectopic cilium—an aberrant hair that arises from a Meibomian gland and emerges through the palpebral conjunctiva. Because the ectopic cilium emerges through the palpebral conjunctiva, it is in constant contact with the ocular surface.

Ectropion—outward rolling of the eyelids.

Electroretingram (ERG)—this is a test that measures the response of the retina to light; that is, it is a test of ­retinal function.

Enophthalmos—refers to position of the globe when it is set more posteriorly­ than normal within the orbit.

Entropion—inward rolling of the eyelids that results in eyelid hairs directly rubbing against the cornea.

Enucleation—surgical removal of the eye, third eyelid, conjunctiva, and eyelid margins.

Epiphora—spillage of tears onto the face.

Exenteration—surgical removal of all orbital contents (i.e., removal of all other orbital soft tissues in addition to enucleation). This is usually performed to remove ocular or orbital neoplasia.

Exophthalmos—refers to position of the globe when it is set more anteriorly than normal within the orbit.

Fundus—the image obtained when the posterior segment is viewed through the pupil with an ophthalmoscope. The image is created by a superimposition of the retina and optic nerve upon the choroid (which includes the tapetum) and sclera.

Glaucoma—optic nerve damage as a result of increased intraocular pressure (intraocular pressure greater than 25 mm Hg).

Goniodysgenesis—congenital malformation of the iridocorneal angle. Also referred to as pectinate ligament dysplasia.

Gonioscopy—visual examination of the iridocorneal angle. This test is performed by a veterinary ophthalmologist. It is most often used to determine if glaucoma is primary or secondary.

Hyphema—blood in the anterior chamber. Presence of hyphema indicates­ anterior uveitis.

Hypopyon—pus in the anterior chamber. Presence of hypopyon indicates anterior uveitis.

Hypotony—decreased intraocular pressure. This is often a symptom of anterior uveitis.

Iridocorneal angle—the angle created by the iris and the cornea. This is the main exit pathway for aqueous humor from the eye. This aqueous outflow pathway is referred to as the conventional pathway.

Iridocyclitis—inflammation of the iris and ciliary body. Iridodonesis—visible movement of the iris seen as a result of zonular

breakdown (indicates lens instability). Keratectomy—surgical removal of a portion of the cornea.