Nervous layer and visual pathway

• What are the three layers of the eyeball?

  Fibrous layer, vascular layer, nervous layer
• What is the fibrous layer of the eyeball composed of?

  Sclera and cornea
• What structures are included in the vascular layer of the eyeball?

  Iris, ciliary body, choroid

  
• What are the components of the nervous layer of the eyeball?

  Pigment layer and neural layer
• What is the tunica fibrosa bulbi?

  It is the fibrous layer of the eyeball
• What is the tunica vasculosa bulbi?

  It is the vascular layer of the eyeball
• What is the tunica interna bulbi?

  It is the nervous layer of the eyeball
• What are the main landmarks of the eyeball?

  Anterior pole, posterior pole, geometrical axis
• What is the surface area of the retina?

  About 1,094 mm²
• Where is the retina thickest?

  Near the optic disc at 560 µm
• Where is the retina thinnest?

  At the foveal floor at 100 µm
• What is the foveal position in relation to the optic disk?

  11.8° or 3.4 mm temporal
• What is the size of the optic nerve head?

  1.86 × 1.75 mm

  
• What is the cross diameter of the macula?

  3 mm of intense pigmentation
• How much does one degree of visual angle equal on the retina?

  288 µm without correction for shrinkage
• How does pigmentation affect the retina's appearance?

  It determines the color of the fundus
• What is the appearance of the fundus in lightly pigmented individuals?

  Very light colored fundus

  
• What is the appearance of the fundus in darkly pigmented individuals?

  Typically more heavily pigmented fundus
• What are the visible landmarks of the retina?

  • Retinal blood vessels
  • Peripheral retina and ora serrata
  • Optic disc
  • Area centralis (macula) with fovea and foveola

  
• What is the arterial supply and venous drainage of the retina?

  Arterial supply:

  • Central retinal artery
  • Posterior ciliary artery

  
  

  Venous drainage:

  • Arcade veins -> Central retinal vein
  • Choroidal veins -> Vortex veins

  
• What are the zones of the retina?

  • Zone 1: Near periphery
  • Zone 2: Mid periphery
  • Zone 3: Far periphery
  • Ora serrata
• What is the ora serrata associated with?

  Increased risk of retinal detachment
• What is the width of the ora serrata temporally?

  2.1 mm
• What is the width of the ora serrata nasally?

  0.7 mm
• How far is the ora serrata from the limbus temporally?

  7 mm
• How far is the ora serrata from the limbus nasally?

  6 mm
• How far is the ora serrata from the optic disc nasally?

  25 mm
• What is the shape of the optic disc?

  Circular or slightly oval
• What is the diameter of the optic disc?

  Approximately 1.5 mm

  
• What is the physiological cup?

  A depression in the center of the optic disc
• What are the vertical and horizontal diameters of the optic disc?

  1.86 mm and 1.75 mm
• How far is the optic disc from the macula?

  3.4 mm

  
• What does the ISNT rule refer to?

  Normal cup-to-disc ratio
• What does a CDR of 0.3 indicate?

  Cup is 70% smaller than disc
• What does a CDR of 0.9 indicate?

  Cup is 10% smaller than disc
• What are the visible landmarks of the area centralis?

  • Located in the posterior pole
  • Temporal to disc
  • Between arcuate and temporal retinal vessels
  • Elliptical in shape
  • 5.5 mm in diameter
  • Corresponds to 15° of visual field
• What is the diameter of the macula lutea?

  3 mm
• What causes the yellow color of the macula lutea?

  Due to xanthophyll
• How many layers of ganglion cells are present in the macula lutea?

  6-8 layers
• Where is the fovea located?

  In the center of the area centralis