Download Ocular Anatomy - Texas Optometric Association

Ocular Anatomy...where ocular disease occurs!
Michael Bacigalupi, OD, MS, FAAO
Texas Optometric Association Convention – 2010
Tear Film
†Lipid layer- secreted by the Meibomian glands of upper and lower lids. Prevents
evaporation and lubricates.
†Aqueous layer-secreted by the Lacrimal glands. 90% of tear thickness and contains
antibacterial properties.
†Mucus layer-secreted by goblet cells in the conjunctiva. Helps tears stick to cornea.
Tear Film Layers
Tear Film Clinical Notes
†Dry Eyes Can Be Caused by a Lack of Tear Production or an Imbalance in the Three
Layers of the Tear Film
„Treat by either adding moisture (Artificial Tears)
„Preventing loss of moisture (Punctal Plugs)
„Controlling inflammation (Restasis or Steroids)
Cornea
†Most powerful refracting lens
†Avascular tissue
†O.5mm thick centrally and 1.00mm thick peripherally
†Composed of 5 distinct layers
Layers of the Cornea
†Epithelium-stratified squamous cells
†Bowman’s membrane-acellular layer
†Stroma-collagen fibrils make up 90% of corneal thickness
†Descemet’s membrane-basement membrane
†Endothelium-single layer of pump cells
Cornea Clinical Notes
†Keratometry Measures the Front Curvature of the Cornea
†Corneal Topography Shows the Elevation of the Cornea
†Pachymetry Ultrasonically Measures the Thickness of the Cornea.
Aqueous Humor
†Volume = 0.6ml
†Replaced every 100+ minutes
†Produced by the the ciliary body
†Similar to plasma
†Must maintain perfect clarity
Aqueous Clinical Notes
Slit Lamp Can Reveal the Presence of Cells or Protein in the Aqueous As Is Found in
Uveitis or Iritis
†Aqueous Production
Maintains Fluid
Pressure Balance
Within the Eye
Limbus
†Transitional zone between the cornea and the sclera
†Corneal stromal lamellae are less regular and more opaque
†Goes from vascular to avascular
Limbus Clinical Notes
Location Involved in Many Ocular Disease Such As: Phlyctenulosis, Vernal Catarrh, or
Trachoma.
Conjunctiva
†Thin, translucent mucous membrane
†Covers the sclera and the underside of the eyelids
†Contains goblet cells
†Stratified epithelium in 3-7 layers
Conjunctiva Clinical Notes
†Pingueculum
†Pterygium
†All Types of Conjunctivitis (Pink Eyes)
†GPC
Sclera
†Hard, white shell of the eye
†Irregularly arranged collagen fibrils
†0.3mm thick anteriorly and 1.0mm thick posterior
†Optic nerve penetrates through sclera at the posterior foramen
Sclera Clinical Notes
†Episcleritis Is a Common Inflammation of the Sclera
†Scleritis Is a Deep Painful Inflammation of the Sclera Usually Associated With a
Systemic Disease
Iris
†Contractile diaphragm
†Central aperture is the pupil
†Heavily pigmented in brown eyes and less pigmented in green to blue eyes
Iris Clinical Notes
†The Iris Can Become Inflamed or Torn From Trauma
†Neovascularization of the Iris From Advanced Diabetes Can Lead to Glaucoma
Angle of the Eye
†Responsible for aqueous fluid balance
†Ciliary Body- produces aqueous
†Trabecular Meshwork-drains aqueous
†Zonules-suspends the crystalline lens
†Iris root
Angle Clinical Notes
†Critical in Glaucoma
†Location of Laser Treatment in Laser Trabeculoplasty
†Can Become Clogged With Pigment or Neovascularization
Leading to IOP
Spikes.
Crystalline Lens
†Transparent biconvex lens
†Suspended in place by the zonules
†Location of cataracts
†Composed of multiple layers like an onion
Crystalline Lens Clinical Notes
†Cataracts Are One of the Most Common Eye Diseases
„Nuclear Cataracts Cloud the Center of the Lens and are Age Related
„Cortical
„Posterior Subcapsular Cataracts Can Be Caused by Age, Trauma, or Steroid Usage.
Three Most Common Cataracts
Cataracts
†What does the patient see?
Vitreous Humor
†Fills the largest chamber of the eye
†4.5ml of volume
†Transparent gel composed of
a random network of thin
Collagen fibers
†Attaches to the optic nerve head and the peripheral retina
Vitreous Humor Clinical Notes
†Aging Causes the Vitreous to Degenerate and Liquefy
†This Can Lead to a
Posterior Vitreous
Detachment with
Symptoms of
Floaters and Flashes of Light
†PVD’s Increase the Risk of Retinal Detachment by 15-20%.
Retina
†Internal lining of the eye
†The “film of the camera”
†Contains photoreceptors – rods and cones
†2 basic layers – neural retina and RPE
Retinal Layers
Retina Clinical Notes
†Retinal Detachment Is an Emergency That Needs
Treatment to Restore the Blood Supply As Quickly As Possible
Macula
†The central 3 disc diameters of the retina
†Tightly packed with cones provides sharpest visual acuity
Age Related Macular Degeneration
†ARMD
„Dry form: atrophy
and aging with drusen
and RPE damage
„Wet form: bleeding from neovascular membrane with exudates and drusen
Optic Nerve
†Formed by the axons of 1.2 million ganglion cells
†Contains the central retinal artery and vein
†Central cupping is
present at the optic
nerve head
†Travels back through
the orbit, through the
posterior foramen,crosses
at the optic chiasm,
travels back to the occipital lobe
Optic Nerve Head
Optic Nerve Clinical Notes
†Glaucoma shows increased cupping of the ONH
†Papilledema is swelling of the ONH and can be caused by increase intracranial pressure
†Pallor indicates poor circulation to the ON
†OHN appears smaller in hyperopes and larger in myopes
Optic Nerve Pathway
†Intraocular
†Intraorbital
†Intracanalicular
†Chiasm
†Intracranial
MRI Optic Pathway
Ocular Anatomy Review
Thank You for Your Attention!
Michael Bacigalupi,OD, MS, FAAO
[email protected]