Ocular Disease III: Lecture 1: Normal Retina/Retinal Potpourri Flashcards
Layers of the Retina
- Anterior to Posterior: Name them!
- ILM
- Nerve Fiber Layer
- Ganglion Cell Layer
- IPL
- INL
- OPL
- ONL
- ELM
- Rods and Cones
- RPE
General Topography of the Retina
- Photo = ?
- Cross Section = ?
- Retina has 10 Layers and many cell types = ?
- It’s organized into regions CENTRAL to PERIPHERAL and each Cellular Layer also has its own Organization
- ACROSS
- DOWN
- Down-Cross Section
- Across
Retinal Landmarks (KNOW)
- Optic Nerve
a. Disc Diameter in size? (ALWAYS THIS)
b. How many MICRONS is about .33 DD
c. So what is the size of the ONH?
d. Normal (mm Length x width)
- VESSELS (KNOW)
a. the 1st VEIN is about what size (Microns)? - Degrees to mm Conversion: 1 DEGREE = how many Micrometers
- a. 1 DD
b. about 500 microns
c. 1.5-2 mm in size
d. 1.86 x 1.75 mm - a. 120 um (microns)
- 1 degree = 288 um
Dimensions
- Foveola: Floor of the Foveola (mm)?
- Fovea Rod Free Zone?
- FOVEA length Across?
a. what is it? - Parafovea: What cells are HIGHEST here?
- Perifovea: Thickness of Ganglion Cells here?
- MACULA: Length across?
- Posterior Pole (degrees)
- Ora to Ora Length (mm)?
- Fovea is how many degrees TEMPORAL from the disc?
- 0.35 mm
- 250-750 um
- 1.5 mm ACROSS
a. Shallow depression in the Center of the Macula - Retinal Bipolar and Ganglion Cells (0.5 mm)
- Ganglion Cells are 4 cells thick to where they are 1 cell thick (1.5 mm)
- 4 mm ACROSS
- 45 degrees
- 32 mm
- 11.8 degrees
Bruch’s Membrane
- Posterior to Anterior (5 Layers)
- Basement Membrane of Choriocapillaries
- Outer Collagenous Layer
- Elastic Lamina
- Inner Collagenous Layer (DENSE LAYER and where DRUSEN 1st ACCUMULATES)
- Basement Membrane of the RPE
Choroid
- Anterior to Posterior (3 Layers)
- Choriocapillaries (Single layer of Capillaries and they’re FENESTRATED)
- Sattler’s Layer (Small Vessels)
- Hallers Layer (Large Vessels)
* Posterior
Normal Retinal Blood Supply (MEMORIZE: WILL BE ON THE TEST)
- Starting with the COMMON CAROTID ARTERY: Describe the Track that leads to the Blood Supply of the Retina and what each thing supplies.
- Common Carotid Artery –> Internal Carotid Artery –> Ophthalmic Artery
a. Opthalmic Artery –> Central Retinal Artery (CRA) –> SUPPLIES INNER RETINA
b. Ophthalmic Artery –> Anterior Ciliary Artery –> SUPPLIES ANTERIOR UVEA & Anterior Choriocapillaris
c. Ophthalmic Artery –> Posterior Ciliary Arteries
i. Short: SUPPLIES NASAL/TEMPORAL Choriocapillaris
ii. Long: Supplies PERIPHERAL Choriocapillaris
Retinal Blood Supply (KNOW)
- CRA:
a. Branches run in what Layer?
b. It has ADHESIONS to WHAT LAYER?
c. Superficial Capillary Network runs in what 2 Layers?
d. Deep Capillary Network runs in what?
e. Overall: It supplies what 5 layers? (what do we call it?)
- a. NFL
b. ILM
c. NFL and GCL
d. INL
e. ILM, NFL, GCL, IPL, INL (INNER RETINA!)
Retinal Blood Supply (KNOW)
- Posterior Ciliary Arteries
a. What does it supply blood to?
b. This in turn supplies what 5 layers?
c. Number of SPCA (short)?
i. Supplies what area of the Retina?
d. LPCA (Long): Number of them?
i. Where are they found?
ii. What part of the retina does it supply?
- a. Choriocapillaris
b. OPL, ONL, ELM, Photoreceptors, and the RPE!
c. 10-15
i. Supplies the Posterior 2/3 of the OUTER RETINA
d. 1-2
i. 1 is Nasal, and 1 is Temporal
ii. the Anterior 1/3 of the OUTER RETINA
Regulation of Retinal BF (KNOW!)
- Does the Neural System regulate this?
- How is it Regulated then?
a. What happens if CO2 INCREASES above threshold?
b. If CO2 DECREASES below threshold?
c. What happens if the PRESSURE GETS to be TOO HIGH?
- NO!!!
- Via AUTOREGULATION in the INNER RETINA!
a. VESSELS DILATE, causes Increased Flow and Decreased Resistance
b. Vessels CONSTRICT, results in Decrease Flow, Increased Resistance, Increased Pressure
c. Vessels will CHANGE TONE (MYOGENIC RESPONSE) to RESIST the Change in IOP!
Retinal Arteries and Veins
- Arteries
a. It’s a TRUE ARTERIOLE; Where do they lie?
b. Are they Strong or Weak?
c. Muscle type?
d. Elastic Lamina?
e. Hemorrhages? - Veins
a. True Venule; Thick or Thinned Walled?
b. 2 things about them: ALLOWS for SVP (Spontaneous Venous Pulsation)
- in NFL or GCL
b. STRONG
c. Smooth Muscle
d. NO
e. Pre-Retinal Hemorrhages - a. THIN Walled
b. DISTENSIBLE and COMPRESSIBLE
Pre-Retinal Hemorrhages
- Where are they located?
a. Where do they come from?
b. How fast do they Clear up?
c. It’s a sign of what 2 types of diseases?
d. Does it OBSCURE underlying vessels?
e. Can you see the Choroid or Retina?
- POSTERIOR to the ILM and ANTERIOR to the NFL
a. from the SUPERFICIAL CAPILLARY BED
b. CLEARS FASTEST of ANY HEMORRHAGE
c. Peripheral Vascular Disease and Arterial Disease
d. YES. OBSCURES UNDERLYING VESSELS!
e. BLOCKS NFL DETAIL and VISION. so NO!
Flame Shaped Hemorrhages
- Where does it Come from?
- What does it FOLLOW?
- Also CALLED what kind of HEMORRHAGE?
- Duration?
- MOST COMMONLY ASSOCIATED with what 2 THINGS!!?
- Post-Arteriolar Superficial Capillary Bed
- Contours of the NFL
- NFL Hemorrhage
- Short usually (6 weeks)
- RETINAL VEIN OCCLUSIONS and HYPERTENSIVE RETINOPATHY
Dot and Blot Hemorrhages
- Where does it come from?
- Located in WHAT LAYER?
- Tells us that it’s what kind of DISEASE?
a. Most ASSOCIATED with what 2 things? - What does it BLOCK on FA?
- How long does it take to Resolve?
- Pre-Venule DEEP Capillary Bed
- OPL
- Venous Congestive Disease
a. DIABETIC RETINOPATHY and OSCULAR ISCHEMIC SYNDROME - NaFl
- Slower to resolve
Sub-Retinal Hemorrhages
- It’s Secondary to what?
- Cause? (Breakthrough of what)
- Location?
- How is it identified (by our ability to do what)?
- to Choroidal Neovascular Membrane (CNVM)
- of Deep Hemorrhages
- B/w RPE and Sensory Retina
- to see DISTINCT Retinal Vessels overlying the hemorrhaging area. (if you see the retinal vessels, then the hemorrhage must be beneath the retina)