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Corneal Anatomy FFCCF! • Mantis Shrimp have 16 cone types- we humans have three- essentially Red Green and Blue receptors. Whereas a dog has 2, a butterfly has 5, the Mantis Shrimp may well see the most color of any animal on earth. Functional Morphology of the Vertebrate Eye Christopher J Murphy DVM, PhD, DACVO Schools of Medicine & Veterinary Medicine University of California, Davis With integrated FFCCFs Why Does Knowing the Functional Morphology Matter? • The diagnosis of ocular disease relies predominantly on physical findings by the clinician (maybe more than any other specialty) • The tools we routinely employ to examine the eye of patients provide us with the ability to resolve fine anatomic detail • Advanced imaging tools such as optical coherence tomography (OCT) provide very fine resolution of structures in the living patient using non invasive techniques and are becoming widespread in application http://dogtime.com/trending/17524-organization-to-provide-free-eye-exams-to-service- • The basis of any diagnosis of “abnormal” is animals-in-may rooted in absolute confidence of owning the knowledge of “normal”. • If you don’t “own” the knowledge of the terminology and normal functional morphology of the eye you will not be able to adequately describe your findings Why Does Knowing the Functional Morphology Matter? • The diagnosis of ocular disease relies predominantly on physical findings by the clinician (maybe more than any other specialty) • The tools we routinely employ to examine the eye of patients provide us with the ability to resolve fine anatomic detail http://www.vet.upenn.edu/about/press-room/press-releases/article/ • Advanced imaging tools such as optical penn-vet-ophthalmologists-offer-free-eye-exams-for-service-dogs coherence tomography (OCT) provide very fine resolution of structures in the living patient using non invasive techniques and are becoming widespread in application • The basis of any diagnosis of “abnormal” is rooted in absolute confidence of owning the http://aibolita.com/eye-diseases/37593-direct-ophthalmoscopy.html knowledge of “normal”. • If you don’t “own” the knowledge of the terminology and normal functional morphology of the eye you will not be able to adequately describe your findings http://www.exam-vision.com/our-products/loupes.php Why Does Knowing the Functional Morphology Matter? • The diagnosis of ocular disease relies predominantly on physical findings by the clinician (maybe more than any other specialty) • The tools we routinely employ to examine the eye of patients provide us with the ability to resolve fine anatomic detail • Advanced imaging tools such as optical coherence tomography (OCT) provide very fine resolution of structures in the living patient using non invasive techniques and are becoming widespread in application • The basis of any diagnosis of “abnormal” is rooted in absolute confidence of owning the knowledge of “normal”. http://www.drquan.ca/retinal_OCT.html • If you don’t “own” the knowledge of the terminology and normal functional morphology of the eye you will not be able to adequately describe your findings Why Does Knowing the Functional Morphology Matter? • The diagnosis of ocular disease relies predominantly on physical findings by the clinician (maybe more than any other specialty) • The tools we routinely employ to examine the eye of patients provide us with the ability to resolve fine anatomic detail • Advanced imaging tools such as optical coherence tomography (OCT) provide very fine resolution of structures in the living patient using non invasive techniques and are becoming widespread in application • The basis of any diagnosis of “abnormal” is rooted in absolute confidence of owning the knowledge of “normal”. • If you don’t “own” the knowledge of the terminology and normal functional morphology of the eye you will not be able to adequately describe your findings Why Does Knowing the Functional Morphology Matter? • The diagnosis of ocular disease relies predominantly on physical findings by the clinician (maybe more than any other specialty) • The tools we routinely employ to examine the eye of patients provide us with the ability to resolve fine anatomic detail • Advanced imaging tools such as optical coherence tomography (OCT) provide very fine resolution of structures in the living patient using non invasive techniques and are becoming widespread in application • The basis of any diagnosis of “abnormal” is rooted in absolute confidence of owning the knowledge of “normal”. • If you don’t “own” the knowledge of the terminology and normal functional morphology of the eye you will not be able to adequately describe your findings https://www.google.com/search? q=writing+a+veterinary+medical+record&client=safari&biw=1200&bih=617&source =lnms&tbm=isch&sa=X&ved=0ahUKEwj6t5KWoKXLAhUH2mMKHZHrCioQ_AU IBigB#tbm=isch&q=veterinarian+writing+medical+record&imgrc=TywEW427rVhql M%3A Bottom Line If you don’t “own” the knowledge of the terminology and normal functional morphology of the eye you will not be able to adequately describe your findings in your records or to another clinician and you will not be prepared to adequately diagnose and treat patients with ocular disease. Keep your eye on the prize…..This isn’t anatomy for anatomy’s sake, it’s an absolute requirement for you to be a competent clinician. Learning Objectives: Eye As A Whole • To “own” knowledge of the functional morphology of the vertebrate eye – Basic design of “Joe” vertebrate eye and essential (additive) variations between vertebrate classes – Appreciate the wide variation in globe shape, size and relative dimensions of the ocular structures and spaces – Know the landmarks and terminology routinely used for spatial location of ocular structures and lesions Comparative Ophthalmology Crocodile fish 30,100 spp. 5,699 spp. 10,000 8,163 spp. Spp. 10 Mammals: 4,629 species RR Dubielzig:OSOD 11 Though fascinating, we won’t be discussing the beautiful designs and wide variation in ocular structure found in invertebrates http://www.eyedesignbook.com/ch3/eyech3-b.html www.pbrc.hawaii.edu/bemf/ microangela/solar.htm www.pbs.org/wgbh/nova/leopards/ cuttlefish.html Joe Vertebrate Eye The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. Landmarks of the Vertebrate Eye Note that a visual axis is present only for animals that have a discrete area of high cone density (and thus high resolution) typified by the fovea of humans, other primates, lizards and birds or an area centralis such is found in dogs and cats. Also, a true canal of Schlemm is found in humans, primates, rodents and birds. Domestic animals have a corneoscleral venous plexus a.k.a. an angular aqueous plexus (i.e not a single continuous channel that is a characteristic of Schlemm’s canal). All Vertebrates Adhere to the Basic Plan! ! ! All Variations are Additive Fish Crocodile fish • flat cornea • ± pigment in cornea • scleral cartilage • ± scleral ossicles (nasal and temporal) • ± choroidal gland (pseudobranch www.pacificislandbooks.com/stufdwnld.html dependent) • spherical lens • annular ligament • retractor (teleost)/protractor (sharks) lentis muscles • falciform process • avascular retina with retinomotor movement www.optiquatics.com/…/pages/M2.%20Bob%20Stewart.%20fish Amphibians (frogs, salamanders, caecilians) • water-air transitions (lids & nictitans develop on metamorphosis) • usually cartilage in sclera • wide range of pupil shapes • ± oil droplets in cones of avascular retina http://www.mascarino.com/RedEyeLeafFrogs.html Reptiles (crocodilia, chelonia, ophidia, lacerta) • scleral ossicles & cartilage cup (not snakes) • striated muscle in iris and ciliary body • ± annular lens pad • ± conus papillaris • avascular retina zoltantakacs.com/zt/ pw/sn/s06.shtml Birds • scleral ossicles & cartilage • annular pad • striated iridal and ciliary muscles • pteridine and lipidoidal iris pigments • ciliary processes fuse to lens capsule • corneal and lenticular accomodative mechanisms • pecten oculi • avascular retina Mammals • smooth muscle in iris and ciliary body • lens suspended by zonules • lenticular accommodation Human fundus • only group with “true” retinal vessels Eye Size & Volume: Wide Variation Cynomolgus Adult Mouse Rat Rabbit Cat Dog Pig** monkey Human Mean axial globe length (mm)* 3.2 6.27 16.83 19.96 20.65 23.9 17.58 23.6 *With the exception of the pig, means are calculated from literature values derived via in vivo methodologies. **Mean calculated from literature values derived via ex vivo methodologies. Comparative Ocular Volumes By Species Cynomolgus Adult Mouse Rat Rabbit Cat Dog Pig monkey Human Mean anterior chamber (AC) 6 13 229 837 381 300 98 181 volume (µl)* Mean lens volume (ml)** 0.005 0.043 0.473 0.5 0.5 0.502 0.125 0.155† Mean vitreous chamber (VC) 0.0053‡ 0.057† 1.153‡ 2.533† 2.65‡ 2.89‡ 1.9† 4.85‡ volume (ml) * All means for AC volume are calculated from literature values derived via in vivo methodologies. ** Unless otherwise specified, all means for lens volume are calculated from literature values derived via ex vivo methodologies or geometric calculation. † Mean derived from literature values derived via in vivo methodologies. ‡ Mean derived from literature values derived via ex vivo methodologies or geometric calculation. And………………. Eye Size: Affects Optics (smaller the eye the more the mag) Murphy CJ, Howland HC, The optics of comparative
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