Please enable JavaScript.
Coggle requires JavaScript to display documents.
OPTHAMOLOGY (*Diabetic Retinopathy
differentiated into either…
OPTHAMOLOGY
*Diabetic Retinopathy
- differentiated into either proliferative or non-proliferative
- two main factors, one from the
--> initial high hyperglycemia causes general inflammation and damage
--> then the VEGF for proliferation of blood vessels
*NON - proliferative Diabetic Retinopathy
- differentiated into either proliferative or non-proliferative
- main factor for NON - proliferative
--> initial high hyperglycemia causes general inflammation and damage
- hyperglycemia causes damage through osmotic effects from conversion to sorbitol by the Polyol pathway
Pathophys of glucose, sorbitol, fructose pathway
- sorbital = osmotic agent that gets trapped inside cells once aldose reductase converts glucose into sorbitol
- sorbital is then converted to fructose by sorbitol DH (dehydrogenase)
--> but this is a slow process so if the polyol pathway gets overloaded, the sorbitol can't be converted and causes osmotic damage to the eyes
- the glucose, sorbitol, fructose pathway can cause many disease
--> diabetic NON-proliferative retinopathy
--> cataracts
-
*proliferative Diabetic Retinopathy
- differentiated into either proliferative or non-proliferative
- main factor for proliferative
--> VEGF for proliferation of blood vessels
- VEGF = vascular endothelial growth factor
*Visual Pathways
- "right stays right"
- "left stays left"
"John MEYER is a TEMPLE GOD in the SKY"
--> temporal lobe = Meyer's Loop
--> "pie in the sky lesion""Baumis BAKER"
--> "Pie on the floor"
Bitemporal (BT) Hemianopia
- anything that pushes on the optic chiasm that lies above the sella turcica can cause BT hemianopia
- Craniopharyngioma is a benign tumour of the anterior pituitary gland that pushes upwards from the sella turcica and diaphragma sellae and pushes onto the optic chiasm
--> presents with ant. pit. endocrine hormone dysfunction and BT hemianopia
Clinical Cases
-
Visual Pathways
-
Bitemporal (BT) Hemianopia
- anything that pushes on the optic chiasm that lies above the sella turcica can cause BT hemianopia
- Craniopharyngioma is a benign tumour of the anterior pituitary gland that pushes upwards from the sella turcica and diaphragma sellae and pushes onto the optic chiasm
--> presents with ant. pit. endocrine hormone dysfunction and BT hemianopia
PCA Infarcts
- have MACULAR SPARRING
- if it is the Meyer and Baum Loops combined then there is no sparring
- maculr sparing is due to watershed of the PCA and MCA
-
*Visual Cortex
- Calcarine Cortex
- Upper Calcarine = Palate of mouth = "Cutaneous" = Cuneus Gyrus
- Lower Calcarine = Tongue of mouth = "Lingual" = Lingual Gyrus
- Meyer's Loop = "pie in the sky" lesion
--> "John MEYER is a guitar GOD" and deserves a "TEMPLE"
--> Meyer runs through temporal lobe
- Dorsal Optic Radtion = Baumi's Loop = "pie on the floor" lesion
--> PIE on the floor = parietal lobe
*Meyer's Loop (Temporal lobe) vs Barum's Loop of the parietal lobe
- "Pie in the sky" = "John Meyer in the sky"
--> "John Meyer has a TEMPER"
--> upper quadrant hemianopias
- The UPPER optic radiations carry the lower visual fields
--> makes sense since they are above so they catch the lower visual fields
--> "pie on the floor"
*Meyer's Loop (Temporal lobe) lesion
- "Pie in the sky" = "John Meyer in the sky"
--> "John Meyer has a TEMPER"
--> upper quadrant hemianopias
- The UPPER optic radiations carry the lower visual fields
--> makes sense since they are above so they catch the lower visual fields
--> "pie on the floor"
-
*Barum's Loop of the parietal lobe lesion
- "Pie in the sky" = "John Meyer in the sky"
--> "John Meyer has a TEMPER"
--> upper quadrant hemianopias
- The UPPER optic radiations carry the lower visual fields
--> makes sense since they are above so they catch the lower visual fields
--> "pie on the floor"
*Palsys and lesions of CN affecting the Eyes
- CN 2 nerve lesion
- CN 3 nerve lesion
- CN 4 nerve lesion
*Trochlear CN 4 Palsy / lesions of CN affecting the Eyes
- CN 4 supplies the SO of the eye
--> "TROCHLEAR CN looks down and out at the trochlea"
--> towards the elbow
- vertical and torsional diplopia
--> down toward the nose accomadation
--> "diplopia going DOWN the stairs"
- eyes point upward
--> note they don't go inward as the lateral/medial rectus are intact
--> unnoposed CN 3 Inferior oblique pulls the eye upward
- Classic Chin tuck away from the lesion
-
*Occular CN 3 Palsy / lesions of CN affecting the Eyes
- CN 3 supplies all muscles of the eye
--> EXCEPT lateral CN 6 lateral rectus and CN 4 SO
- vertical and torsional diplopia
--> down toward the nose accomadation
--> "diplopia going DOWN the stairs"
- eyes point in direction of the SO
--> note they don't go inward as the lateral/medial rectus are intact
--> unnoposed CN 3 Inferior oblique pulls the eye upward
- ptsosis = since levator palpebra of CN 3
- accomodation loss = CN 3 is efferent of accomodation reflex
*Abducins CN 6 Palsy / lesions of CN affecting the Eyes
- CN 6 supplies lateral rectus
- horizontal diplopia
--> since no lateral rectus to pull them laterally
- eyes point medially inward
--> since no lateral rectus to pull them laterally
*Refraction of Eyes
- myopia = MY NEAR LITTLE TINY CAVE
--> focus in front of the lens
--> need to push out with TINY CAVE = convex lens
- hyperopia = HIGH in SKY
--> focus = far past the lens
--> needs more CURVE = Convex lens
- PRESBYOPIA = old Presbyterians
--> old age loss of myopia and accomodation
--> note myopia people get improvement since they already see NEAR things too well
*PRESBYOPIA of Eyes
- PRESBYOPIA = old Presbyterians
--> old age loss of myopia and accomodation
--> note myopia people get improvement since they already see NEAR things too well
-
*CRAO = central retinary artery occlusion
- from an emboli usually
- presents with very sudden and painless loss of vision
- treat as a regular CVA workup and look for source and other emboli
-
*Red reflex
- Negative red reflex = white
- checks for 2 things:
--> cataracts
--> retinoblastoma
-
*AMD = Age-related macular degeneration
- AMD is most common cause of blindness in people over 50
- DRY AMD
--> get deposits of fatty tissue = Drussen behind the retina of the macula
- WET AMD
--> get neovascularization underneatht he retinal layer that creeps up
--> this is more dangerous and leads to blindness
-
*Glaucoma
- 1st line tx = latanoprost
-
