AVIAN OPHTHALMOLOGY - Expressions of virus disorders Rüdiger Korbel, Dip ECZM (Avian)/Munich/Germany & Monika Rinder, Priv. Doz. Dr. med. vet. Clinic for Birds, Reptiles, Amphibians & Ornamental Fish University Ludwig Maximilians Munich / Germany (Director: Prof. Dr. Rüdiger Korbel) Avian Ophthalmology . . . but why? Significance Incidence „Diagnostic window Expression of systemic disorders! The Ophthalmologist´s Gear I The Ophthalmologist´s Gear pt1 The Ophthalmologist´s Gear pt2 Avian Ophthalmology . . . but why? Significance Incidence „Diagnostic window Expression of systemic disorders! What´s the difference?! Ear opening Saccadic eye movements Pupillary reflex Consensual light reflex Tarsus Puncta lacrimalia Filtration angle Fundus Through the eyes of a bird Through the eyes of a bird Visual Perception Poultry Man Light Perception & Outer Appearance Bird Man UV - Vision in Birds Intra & interspecific communication Sexual dimorphism Sexual attraction Crypsis Rearing Assessment of food Detection of prey patches Flicker fusion frequency The ability to dissolve movements into single frames (18 Hz (man) vs. < 160 Hz (avian) UV & Flicker - Deficiency Malfunction of vision Malfunction of food selection Malfunction of rearing Social misbehaviour Low reproduction rates Featherplucking Cannibalism Suitable UV-Lightsources Luxmeter Anatomical annotations What´s the difference? Adnexal structures Ear opening Oscillatory (saccadic) eye movements Tarsal plate Anterior eye segment Striated rather than smooth intraocular musculature Spontaneous (voluntary) pupillary movements Unreliable pupillary response to light stimuli No indirect pupillary reflex Juvenile & immature lens might appear as „cataract“ What´s the difference? Posterior eye segment (fundus) Pecten oculi Optic nerve head (almost) obscured by pecten No tapetum lucidum One, two or no fovea Lack of retinal vascularisation (retina (anangiotic retina) Heavily pigmentation of RPE in diurnal birds Little pigmentation of RPE in nocturnal bird species Shape of avian eyes Common Tawnybuzzard Owl (OS, (OD, ventral ventral half) half) Bony Sceral Ring OCT SDO Ultrasonography Ophthalmoscopy Pecten Oculi Ophthalmological Imaging Modular Examination Procedures Korbel et al. ICARE 2013 • ABV: Characterisation of ophthalmological lesions using OCT Ophthalmoscopy Examination - Procedures Ophthalmoscopy Example for fundus of diurnal birds: Common buzzard Fluorescein Angiography Online-Tutorial Pathology Fischeye Korbel et al. Untersuchungen an Fischaugen - XV. Tagung der EAFP, Starnberg Oktober 8 - 10, 2014 Disorders Incidence Mammals: 3 % Birds: 7 % Ocular manifestations of systemic disorders! Disorders Birds/Reptiles ocular manifestions of systemic disorders Systemic & transmittable disorders Salmonellosis Psittacosis Mycobacteriosis Newcastle Disease and other 28 Poxvirus-Infection Newcastle Disease Marek´s Disease Herpes-Ceratitis Avian Encephalomyelitis Avian Bornavirus Infections in Parrots: Characterization of ophthalmological lesions using Optical Coherence Tomography (OCT) R Korbel, ME Gallego Velasco, C Schulze, M Rinder Center for Clinical Veterinary Medicine Clinic for Birds, Reptiles, Amphibians and Ornamental Fish University Ludwig Maximilian, Munich/Germany ABV & PDD Emerging psittacine disease ABV --> PDD GI signs CNS signs Ocular signs Avian Retina: Light microscoopy Avian Retina: OCT-Scan Avian Ocular Fundus Comparison Optical coherence tomography & HIstology Korbel et al. ICARE 2013 • ABV: Characterization of ophthalmological lesions using OCT Optical Coherence Tomography (OCT)* *Korbel et al. 2011: Investigations on OCT in avian ophthalmology. 2nd DVG Conference Avian and Reptile Dis. Munich, 2011. Developed since 1980s Interferometric based technique 2 & 3 D ocular layer sections Almost histological resolution CS thickness 100µ (interpol.) Contact free, noninvasive In vivo retinal examination Repeatedly examination Possibility for follow ups of disease stages Optical Coherence Tomography (OCT) Spectralis OCT Plus (Heidelberg Engeenier. Inc/D) Forier-Domain OCT „Eye tracking“ function Simultanious OCT & Infrared-Reflection-Imaging Optical Coherence Tomography (OCT) Principle of OCT evaluation Loss of ocular layer integrity External limiting membrane (ELM) Inner/Outer segment layer (IS/OS) Retinal pigment eithelium OCT Korbel et al. ICARE 2013 • ABV: Characterization of ophthalmological lesions using OCT Common Buzzard, OD, central fundus External limiting membrane (ELM) Inner/Outer segment layer (IS/OS layer) Retinal pigment epithelium (RPE) OCT Common buzzard , 21707, OD, Fovea centralis & Retinal oedema OCT African grey, OD, normal OCT Material & Methods Psittacine individuals n = 21 Psittacine species n = 13 Clinically positive ABV - RNA positive ABV - AB positive Results - Clinics Ocular lesions: 86 % (n = 18) Cataract formation: n = 1 Fundus lesions: n = 17 Clinical blindness: n = 1 Visual impairment: n = 2 Increased oscillatory movement frequency (35 - 40 Hz) Results - SDO African Grey, OS, nasal fundus, Chorioretinitis Results - SDO African Grey, OS, ABV, early stage Results - SDO African Grey, OS, ABV, advanced stage Results - SDO Ocular ABV manifestation, late stage Blue fronted amazone, OS, ABV associated chorioretinitis OCT - Ocular ABV manifestation Blue fronted amazone, OS, ABV associated chorioretinitis OCT - Ocular ABV manifestation African grey, OD, ABV OCT - Ocular ABV manifestation Discussion & Conclusions ABV -- > 85 % ocular lesions Ocular ABV/PDD diagnosis? Progressive disorder All retinal layers affected Trauma Fundus lesions in avian eyes Common Buzzard, OD, Scanning Digital Ophthalmoscope Chorioretinitis Tawny Owl, OS Thank You!
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