1 The Eye and Vision Evolution of the Eye Development of the Eye Basic Anatomy of the Eye Fundamentals of Vision Luminance Motion Depth Perception Texture (Visual Acuity) Optical Factors in Visual Acuity Retinal Factors in Visual Acuity Estimates of Visual Acuity Color Vision Central Visual Pathways Suggested Reading 2 The Ophthalmic Examination and Diagnostic Testing Collecting a Complete Ophthalmic History The Ophthalmic Examination Procedure Assessment From a Distance, Retropulsion, and Behavioral Visual Testing Neuroophthalmic Testing Menace Response Palpebral Reflex Oculocephalic Reflexes Assessment of Pupil Symmetry Using Retroillumination Pupillary Light Reflexes The Swinging Flashlight Test Dazzle Reflex Examination of the Anterior Segment Eyelids Conjunctiva Third Eyelid Nasolacrimal Apparatus Sclera Clinical Differentiation of Episcleral and Conjunctival Hyperemia (or “Injection”) Cornea Anterior Chamber Iris and Pupil Lens Ophthalmoscopy Indirect Ophthalmoscopy Direct Ophthalmoscopy Monocular Indirect Ophthalmoscopy Examination of the Posterior Segment Vitreous The Fundus Additional Diagnostic Testing Three Essential Tests in Most Ophthalmic Patients Tear Film Testing Assessment of Basal and Reflex Aqueous Tear Production (STT-1) Assessment of Basal Aqueous Tear Production (STT-2 and the Phenol Red Thread Test) Assessment of Tear Film Stability Tonometry Indentation Tonometry Applanation Tonometry Rebound Tonometry Normal Intraocular Pressure Application of Ocular Stains (Fluorescein, Rose Bengal, and Lissamine Green) Fluorescein Rose Bengal and Lissamine Green Additional Diagnostic Testing in General Practice Ocular Surface Sampling Cytologic Samples Microbiological Samples Assessment of the Nasolacrimal Apparatus (Jones Test and Nasolacrimal Flushing) Ultrasonography Radiography Additional Diagnostic Testing Typically Done in Specialty Practice Gonioscopy Electroretinography and Visual Evoked Potentials Retinoscopy Computed Tomography and Magnetic Resonance Imaging Suggested Reading Ophthalmic Examination Techniques Tear Testing Tonometry Ocular Surface Sampling Retinoscopy Diagnostic Imaging Other Diagnostic Techniques 3 Ophthalmic Medications and Therapeutics Routes of Ocular Drug Administration Topical Formulations Solutions, Suspensions, and Gels (“Eye Drops”) Ointments Subconjunctival, Sub-Tenon’s, Peribulbar, and Retrobulbar Injections Systemic Drug Administration Antibacterial Drugs Selection and Administration of Antibiotics Penicillins Cephalosporins Chloramphenicol Aminoglycosides Neomycin Gentamicin and Tobramycin Amikacin Cyclic Polypeptides Bacitracin Polymyxin B Tetracyclines Azithromycin Sulfonamides Fluoroquinolones Enrofloxacin, Orbifloxacin, and Pradofloxacin Ciprofloxacin, Ofloxacin, Moxifloxacin, Gatifloxacin, and Others Fusidic Acid Antifungal Drugs Natamycin Azoles Amphotericin B Antiviral Drugs Idoxuridine Ganciclovir Penciclovir and Famciclovir Trifluridine (Trifluorothymidine) Cidofovir Vidarabine Acyclovir and Valacyclovir Lysine Interferons Antiparasitic Agents Intraocular Inflammation and Mechanisms of Action of Antiinflammatory Agents Corticosteroids Indications for Corticosteroid Use Ophthalmic Corticosteroids Cautions and Contraindications With Corticosteroid Use Nonsteroidal Antiinflammatory Drugs Indications for NSAID Use Ophthalmic NSAIDs Cautions and Contraindications With NSAID Use Mast Cell Stabilizers and Antihistamines Cyclosporine Lacrimostimulant and Lacrimomimetic Agents Cyclosporine Tacrolimus and Pimecrolimus Pilocarpine Artificial Tears Drugs for Treating Glaucoma Topical and Systemic Carbonic Anhydrase Inhibitors Prostaglandin Analogues Adrenergic Agonists and Beta-Blockers Demecarium Bromide and Pilocarpine Mannitol and Glycerin Mydriatic and Cycloplegic Agents Phenylephrine Atropine Tropicamide Miscellaneous Parasympatholytic Agents Ocular Analgesics Topical Anesthetics Topical Opioids Topical Atropine Topical NSAIDs Systemically Administered Analgesics Regional Orbital Anesthesia Serum and Other Proteinase Inhibitors Tissue Plasminogen Activator Antioxidant Therapies for Cataracts and Retinopathies Preoperative Sterile Preparation of Ocular Sites Nonmedical Therapeutics Contact Lenses Surgical Adhesives Cryosurgery Hyperthermia Lasers in Veterinary Ophthalmology Irradiation ?-Irradiation ? and x-Irradiation Suggested Reading Antibacterial Drugs Antifungal Drugs Antiviral Drugs Ivermectin Antiinflammatory and Immunomodulatory Drugs Lacrimostimulant and Lacrimomimetic Agents Glaucoma Mydriatic and Cycloplegic Drugs Ocular Analgesia Serum and Other Antiproteases Tissue Plasminogen Activator Vitamins, Minerals, and Antioxidants Nonmedical Therapies 4 Principles of Ophthalmic Surgery Introduction Instruments, Suture Materials, and Sutures Basic Instruments for Extraocular Procedures Instruments for Handling of 7/0 Suture and Smaller Instrument and Suture Handling for Ophthalmic Surgeries Additional Supplies for Ophthalmic Surgeries Anesthesia of the Ophthalmic Patient Preparation of the Surgical Site for Ophthalmic Surgeries Positioning for Ophthalmic Surgeries Surgical Exposure for Ophthalmic Surgeries General Principles During Surgery Postoperative Considerations Postoperative Corneal Protection General Postoperative Management and Recovery of the Ophthalmic Patient Suggested Reading 5 Diseases of the Orbit Embryology Anatomy Orbital Bones Extraocular Muscles Lacrimal Gland, Base of Third Eyelid, and Ventral Orbital Fat Pad Orbital Blood Vessels Orbital Nerves Orbital Fascia Structures Surrounding the Orbit Pathological Mechanisms Exophthalmos Enophthalmos Strabismus Diagnostic Methods History Physical Examination Hematology and Serum Biochemistry Diagnostic Imaging Ultrasonography Radiography Advanced Imaging Techniques Fine-Needle Aspiration, Biopsy, and Orbitotomy Orbital Diseases Orbital Cellulitis, Abscessation, and Foreign Body Clinical signs. Workup and treatment. Cystic Orbital and Periocular Lesions Zygomatic Mucocele Clinical signs. Treatment. Neoplasia Clinical signs. Treatment. Feline Restrictive Orbital Myofibroblastic Sarcoma Periorbital Fractures Treatment. Orbital Emphysema Masticatory Muscle Myositis Extraocular Muscle Myositis Proptosis of the Globe Surgical Procedures Enucleation Indications. Lateral Subconjunctival Enucleation Technique Insertion of an Intraorbital Prosthesis Transpalpebral Enucleation–Exenteration Technique Exenteration Ocular Prostheses Intrascleral Prosthesis Systemic Causes of Orbital Disease in the Dog and Cat Suggested Reading 6 Diseases of the Eyelids Embryology, Anatomy, and Physiology Eyelid Opening and Closing General Pathologic Responses Premature or Delayed Opening of the Eyelids in Neonates Eyelid Agenesis (Coloboma) Prominent Nasal Skin Folds Disorders of the Cilia Clinical Signs of Cilia Disorders Treatment of Distichiasis Cryoepilation Electroepilation Treatment of Ectopic Cilia Treatment of Trichiasis Entropion Clinical Signs of Entropion Treatment of Entropion Temporary “Tacking” Techniques Wedge Resection Hotz-Celsus Procedure Combined Hotz-Celsus and Lateral Wedge Resection Lateral Arrowhead Procedure and Tenotomy for Lateral Entropion Medial Canthoplasty for Lower Medial Entropion and Brachycephalic Ocular Syndrome Upper Eyelid Entropion Ectropion Treatment of Ectropion Wedge Resection “V-to-Y” Blepharoplasty Eyelid Injuries Treatment of Eyelid Injuries Nonneoplastic Disorders of the Meibomian and Other Eyelid Glands Chalazia Hordeolum and Meibomian Adenitis Eyelid Neoplasia Squamous Cell Carcinoma Meibomian Adenoma Feline Multiple Apocrine Hidrocystoma Viral Papillomatosis Mast Cell Tumors Histiocytoma Histiocytosis Skin Diseases Affecting the Eyelids Skin Disease Presenting With Periocular Alopecia as the Major Clinical Sign Skin Disease Presenting With Erythema, Scales, and Crusts as the Major Clinical Sign Skin Disease Presenting With Periocular Pruritus as the Major Clinical Sign Skin Disease Presenting With Eyelid Margin Hyperpigmentation as the Major Clinical Sign Skin Disease Presenting With Eyelid Margin Depigmentation as the Major Clinical Sign Skin Disease Presenting With Eyelid Margin Erosion or Ulceration as the Major Clinical Sign Skin Disease Presenting With Blepharitis as the Major Clinical Sign Skin Disease Presenting With Periocular Papules as the Major Clinical Sign Skin Disease Presenting With Solitary Nodules as the Major Clinical Sign Suggested Reading Disorders of the Cilia and Meibomian Glands Entropion/Ectropion Eyelid Neoplasia Skin Diseases Affecting the Eyelids 7 Diseases of the Conjunctiva Embryology, Anatomy, and Physiology Conjunctival Wound Healing Clinical Signs of Conjunctival Disease Conjunctival Hyperemia Chemosis (Conjunctival Edema) Ocular Discharge Conjunctival Ulceration Conjunctival Swelling, Thickening, or Mass Formation Pruritus Conjunctivitis Classification Differential Diagnosis Diagnostic Methods Bacterial Culturing Conjunctival Scrapings Conjunctival Biopsy General Treatment Considerations for Conjunctivitis Antibiotics Corticosteroids Cleansing Agents and Warm-Packing Topical Mast Cell Stabilizers and Antihistamines Vasoconstrictive Agents Bacterial Conjunctivitis Chlamydial Conjunctivitis Treatment Mycoplasmal Conjunctivitis Viral Conjunctivitis Feline Viral Conjunctivitis Diagnostic testing. Treatment of herpetic disease in cats. Canine Viral Conjunctivitis Treatment of herpetic disease in dogs. Mycotic Conjunctivitis Parasitic Conjunctivitis Leishmaniasis Onchocerciasis Immune-Mediated Conjunctivitis Allergic Conjunctivitis Treatment. Feline Epitheliotropic Mastocytic Conjunctivitis Other Conjunctival Disorders Drug Plaques Conjunctival Lacerations Ligneous Conjunctivitis Lipogranulomatous Conjunctivitis Conjunctival Neoplasia Conjunctival Dermoid Canine Conjunctival Papillomatosis Canine Mast Cell Tumors Canine and Feline Conjunctival Vascular Tumors Canine and Feline Melanocytic Tumors Canine Transmissible Venereal Tumors Suggested Reading Diagnostic Testing Chlamydia and Mycoplasma Viral Conjunctivitis and Antiviral Drugs Lysine and the Interferons Parasitic Conjunctivitis Other Conjunctivitides Conjunctival Neoplasia 8 Diseases of the Third Eyelid Embryology, Anatomy, and Physiology Placement of Third Eyelid Flaps Examination of the Third Eyelid Clinical Signs of Third Eyelid Disease Structural Abnormalities of the Third Eyelid Lack of Pigment on the Leading Edge of the Third Eyelid Scrolling of the Third Eyelid Treatment Hyperplastic Lymphoid Follicles on the Bulbar Surface of the Third Eyelid Prolapse of the Gland of the Third Eyelid (“Cherry Eye”) Treatment Complications Following Third Eyelid Gland Replacement Neoplasms Affecting the Third Eyelid Trauma to the Third Eyelid Inflammatory Disorders of the Third Eyelid Foreign Bodies and Parasites Under the Third Eyelid Suggested Reading Anatomy and Physiology Scrolled and Everted Third Eyelid Cartilage Inflammatory Disorders of the Third Eyelid Neoplasia of the Third Eyelid Prolapsed Gland of the Third Eyelid Other Third Eyelid Surgeries 9 Diseases of the Lacrimal System Introduction Embryology, Anatomy, Physiology, and Examination Embryology Anatomy Physiology Tear Film The lipid layer. The aqueous–mucin layer. Blinking, Evaporation, and Nasolacrimal Drainage Tear Film Examination Methods Disorders of the Lacrimal Secretory System Quantitative Keratoconjunctivitis Sicca Etiology Congenital keratoconjunctivitis sicca. Autoimmune keratoconjunctivitis sicca. Neurogenic keratoconjunctivitis sicca. Endocrinologic diseases. Systemic infectious diseases. Toxic or drug-induced keratoconjunctivitis sicca. Other causes of secondary keratoconjunctivitis sicca. Clinical Features Mucoid or mucopurulent ocular discharge. Blepharospasm. Conjunctival hyperemia. Corneal vascularization and pigmentation. Dry and lusterless cornea. Dry ipsilateral nostril. Corneal ulceration. Reduced vision. Diagnosis Medical Treatment Nonspecific topical treatment for quantitative keratoconjunctivitis sicca Eyewash and removal of excess mucus. Artificial tears (lacrimomimetics). Specific topical and systemic treatment for quantitative keratoconjunctivitis sicca (lacrimostimulants). Immunomodulating agents. Pilocarpine. Reducing ocular surface inflammation. Controlling secondary infection. Other medications. Follow-up and reevaluation protocol. Surgical Treatment of Quantitative Keratoconjunctivitis Sicca Parotid duct transposition. Preoperative considerations. Surgical preparation. Surgery. Intraoperative complications. Postoperative treatment. Success rate and postoperative complications. Lacrimal punctal occlusion. Cyclosporine A subconjunctival implants. Qualitative Keratoconjunctivitis Sicca Etiology Clinical Presentation Diagnosis Treatment Mucin-deficiency keratoconjunctivitis sicca treatment. Lipid-deficiency keratoconjunctivitis sicca treatment. Neoplasia of the Lacrimal Glands Nasolacrimal Drainage System Examination Methods Congenital Disorders of the Nasolacrimal Drainage System Congenital Punctal Atresia or Micropunctum Diagnosis. Treatment. Displacement of the Puncta and Canaliculus Diagnosis. Treatment. Canalicular and Nasolacrimal Duct Atresia Diagnosis. Treatment. Dacryops and Canaliculops Acquired Disorders of the Nasolacrimal System Dacryocystitis Clinical signs. Diagnosis. Treatment. Postoperative considerations. Cicatricial Nasolacrimal Obstructions Neoplasia Suggested Reading Lacrimal Secretory System Nasolacrimal Drainage System 10 Diseases of the Cornea and Sclera Embryology, Anatomy, and Physiology Cornea Sclera Normal Corneal Healing Epithelium Stroma Endothelium and Descemet’s Membrane Effects of Corticosteroids on Corneal Healing Pathologic Responses Stromal Malacia (or “Melting”) Corneal Edema Corneal Vascularization Corneal Fibrosis Corneal Melanosis Stromal Infiltration With White Blood Cells Anterior Stromal Deposition of Lipid and/or Mineral Corneal Ulcers in All Species Common Causes of Corneal Ulceration Simple Versus Complicated Ulcers General Principles of Corneal Ulcer Treatment Antibiotics Atropine Analgesic and Antiinflammatory Agents Prevention of Self-Trauma Temporary Tarsorrhaphy Versus Third Eyelid Flap Treatment of Uncomplicated (Simple) Corneal Ulcers Treatment of Deep Corneal Ulcers and Descemetoceles Medical Treatment of Deep Ulcers Protease Inhibitors Surgical Treatment of Deep Ulcers Cyanoacrylate Adhesives (Tissue Glue) Treatment of Indolent Corneal Ulcers in Dogs Corneal Trauma and Foreign Bodies Corneal Lacerations Removal of Corneal Foreign Bodies Epithelial Inclusion Cysts Corneal Diseases Seen Most Commonly in Dogs Corneal Lipid/Mineral Dystrophy Corneal Endothelial Dystrophy Superficial Punctate Keratitis Pigmentary Keratitis/Keratopathy “Pannus” or Chronic Immune-Mediated Superficial Keratoconjunctivitis Canine Herpesvirus Infectious Canine Hepatitis Corneal Diseases Seen Most Commonly in Cats Feline Herpetic Keratitis Feline Eosinophilic Keratoconjunctivitis Feline Corneal Sequestration Acute Bullous Keratopathy Ulcerative Mycoplasmal Keratitis Mycobacterial Keratitis “Florida Keratopathy” or “Florida Spots” or “Tropical Keratopathy” Congenital Corneal Diseases Dermoid Persistent Pupillary Membranes Corneal Epithelial Dysmaturation or “Puppy Dystrophy” Scleral and Limbal Disorders Colobomatous Defects Scleritis and Episcleritis Scleral Trauma Limbal Neoplasia Suggested Reading Anatomy Pathologic Responses Corneal Ulcers and Trauma Corneal Diseases Specific to Dogs Corneal Diseases Specific to Cats Scleral and Limbal Disorders 11 Diseases of the Uvea Anatomy and Physiology Iris Ciliary Body Choroid Blood–Ocular Barrier Pathologic Reactions Definitions Immune Mechanisms Congenital Uveal Abnormalities Abnormalities of the Pupil Persistent Pupillary Membrane Coloboma Anterior Segment Dysgenesis Disorders of Pigmentation Heterochromia Waardenburg Syndrome Iris Nevi Uveitis Sequelae of Uveitis Posterior Synechiae Peripheral Anterior Synechiae Cataract Glaucoma Retinal Detachment Atrophy Preiridal Fibrovascular Membranes Cyclitic Membranes Diagnosis of Uveitis General Therapeutic Principles 1. Make an Etiologic Diagnosis 2. Control Inflammation Corticosteroids. Nonsteroidal antiinflammatory drugs. Immunosuppressive agents. 3. Prevent Undesirable Sequelae Mydriatics and cycloplegics. Antiglaucoma drugs. 4. Relieve Pain Specific Forms of Uveitis Infectious Uveitis Immune-Mediated Uveitis Uveodermatologic syndrome. Lens-induced uveitis. Leakage through the intact lens capsule. Penetrating lens injuries. Uveitis associated with dental disease. Pigmentary uveitis of golden retrievers. Feline uveitis. Toxic uveitis. Trauma Traumatic Uveitis Iris Prolapse Signs Hyphema Etiologic Factors Diagnosis Treatment Additional Therapy for Mild Hyphema Additional Therapy for Severe Hyphema Uveal Cysts and Neoplasms Uveal Cysts Primary Tumors Adenoma and Adenocarcinoma Canine Uveal Melanocytoma and Melanoma Clinical signs. Treatment. Ocular Melanosis of Cairn Terriers Feline Diffuse Iris Melanoma Primary Feline Ocular Sarcomas Secondary Tumors Lymphosarcoma Miscellaneous Disorders Iris Hypoplasia Iris Atrophy Primary or Senile Iris Atrophy Secondary Iris Atrophy Suggested Reading 12 The Glaucomas Aqueous Production and Drainage Balancing Aqueous Production and Outflow Causes of Variations in Intraocular Pressure Diurnal Variation Age Blood Flow Drugs Ocular Inflammation Diagnostic Methods Tonometry Ophthalmoscopy Gonioscopy Clinical Signs Increased Intraocular Pressure Pain, Blepharospasm, and Altered Behavior Engorged Episcleral Vessels Corneal and Scleral Changes Edema Buphthalmos and Descemet’s Streaks Changes in Anterior Chamber Depth Fixed Dilated Pupil Lens Changes Fundus Changes Impaired Vision Optic Disc Cupping Retinal Degeneration Classification Pathogenesis Primary Open-Angle Glaucoma Primary Angle-Closure Glaucoma Secondary Glaucomas Obstruction of the Iridocorneal Angle Pupillary Block Ciliary Body–Vitreous–Lens Block Combined-Mechanism Glaucoma Treatment Emergency Treatment of Acute Glaucoma Long-Term Management of Glaucoma Surgical Therapy for Glaucoma Surgery to Increase Aqueous Humor Outflow Surgery to Reduce Aqueous Humor Production Cyclocryotherapy Laser Cyclophotocoagulation Combined Procedures Lens Luxation Glaucoma Secondary to Uveitis Glaucoma Secondary to Intraocular Neoplasia Absolute Glaucoma Evisceration With Intrascleral Prosthesis Enucleation Feline Glaucoma Suggested Reading 13 Diseases of the Lens Anatomy and Physiology Embryology Gross Anatomy and Function Lens Components Capsule Lens Epithelium Lens Fibers Metabolism and Composition Nuclear Sclerosis Congenital Anomalies Cataract Molecular and Cellular Pathogenesis of Cataracts Classification Degree of Opacity and Maturation Lens-Induced Uveitis Causes of Cataracts Hereditary Cataracts Diabetic Cataracts Senile Cataracts Secondary and Acquired Cataracts Cataracts secondary to ocular disease. Traumatic cataracts. Nutritional cataracts. Cataracts secondary to infection. Cataracts secondary to radiation and toxicity. Developmental Cataracts Diagnosis of Cataracts History Clinical Signs Genetic Testing Treatment of Cataract Medical Therapy Surgical Case Selection Surgical Correction Discission and aspiration. Intracapsular extraction. Extracapsular extraction. Phacoemulsification. Postoperative Vision and Intraocular Lens Implantation Medical Care, Complications, and Prognosis Lens Luxation Etiology Clinical Signs and Progression Treatment Suggested Reading 14 Diseases of the Vitreous Anatomy and Physiology Embryology and Anatomy Composition Function Pathologic Reactions Principles of Diagnosis and Treatment of Vitreal Disorders Diagnosis Hyalocentesis and Intravitreal Injections Drug Delivery Surgical Procedures Vitrectomy Advanced Vitreoretinal Surgical Techniques Congenital and Developmental Abnormalities (Persistent Fetal Vasculature) Persistent Hyaloid Artery Persistent Tunica Vasculosa Lentis Persistent Hyperplastic Tunica Vasculosa Lentis/Persistent Hyperplastic Primary Vitreous Acquired Disorders Vitreous Hemorrhage Inflammation and Infection Vitreous Degeneration Vitreous Opacities (Floaters) Asteroid Hyalosis and Synchysis Scintillans Vitreous Mass Role of the Vitreous in the Pathogenesis of Ocular Diseases Vitreous and Lens Luxation Retinal Detachment Aqueous Humor Misdirection Syndrome Canine Ocular Gliovascular Syndrome Suggested Reading 15 Diseases of the Retina Embryology and Cellular Anatomy Embryology Cellular Anatomy Retinal Pigment Epithelium Blood Supply Physiology and Biochemistry Rods and Cones Visual Photopigments Photochemistry Dark and Light Adaptation Normal Ophthalmoscopic Variations (Applied Anatomy) Sensory Neuroretina Tapetum Nontapetal Fundus Optic Disc (Optic Nerve Head, Optic Papilla) Myelination of Nerve Fiber Layer Blood Vessels Ophthalmoscopic Signs of Fundic Diseases and Their Underlying Pathologic Mechanisms Primary Photoreceptor Disease Inflammations Retina–Choroid Interaction Reactions of Pigment Epithelium Perivascular Cuffing Gliosis