EPT3 Flashcards
Which of the following statements regarding migraines without auras is FALSE?
a. Neuro-imaging should be performed if patients have an initial episodes after the age of 50
b. They develop due to abnormal dilation of blood vessels within the brain
c. They are known as classic migraines
d. They are associated with normal tension glaucoma
c. They are known as classic migraines (FALSE)
Migraines without aura are called common migraines; migraines w auras are known as classic migraines and are less common than migraines without auras. Evidence suggests that migraines are associated with NTG, as they are due to poor regulation of BF, which is thought to play a role in the development of optic neuropathy in NTG. Bc it is rare for an initial migraine episode to occur after the age of 50, neuro-imaging is advised in pts who have an initial migraine episode after the 5th decade of life.
What level of VA is expected for a 6 month old when tested with forced preferential looking cards?
20/100
NOTE: although infants can achieve 20/20 VA by 6 months of age w VEPs, spatial VA does NOT reach 20/20 levels until approx 3-4 years of age. Spatial VA using forced preferential looking cards is ~20/600 to 20/1200 by `1 month of age, and 20/50 to 20/60 by 1 year og age
What is the MOST common cause of spontaneous vitreous hemorrhage in adult patients?
Proliferative diabetic retinopathy
NOTE: PDR is the MOST common cause of spontaneous vitreous hemorrhage in adults (30-50% of cases). Followed by retinal breaks/retinal vein occlusions. Acute PVD may also result in a vitreous hemorrhage, but in a much smaller % of cases compared to the other 3 options
What procedure involved surgically removing the corneal tissue down to Descemet’s membrane?
Deep anterior lamellar keratoplasty (DALK)
Where is a lamellar cataract located?
Between nuclear and cortical layers of the lens - may be acquired from tetany or rickets early in life
A persistent pupillary membrane is due to incomplete regression of what during development?
The Tunic Vasculosa Lentis
Which Purkinje images is a real and inverted image?
IV
NOTE: I: front surface cornea II: back surface of cornea III: front surface of crystalline lens IV: back surface of crystalline lens - also only concave MIRROR surface which produce Real Inverted Images, Virtual upright images or no image at all
For plus lenses, how do you increase spectacle magnification with vertex distance, spectacle lens thickness, base curve, and index of refraction in the myopic (minus lens) to reduce aniseikonia?
Vertex distance: INC
Spectacle Lens thickness: INC
Base Curve: INC
Index of Refraction: DEC
RECALL:
Ms = 1/[1-(t/n)F1’
Mp=1/[1-hFv’]
For minus lenses, how do you increase spectacle magnification with vertex distance, spectacle lens thickness, base curve, and index of refraction in the hyperopic (plus lens) to reduce aniseikonia?
Vertex Distance: DEC***
Spectacle Lens Thickness: INC
Base Curve: INC
Index of Refraction: DEC
Which of the following is found in a high concentration in mature lens fibers?
a. collagen
b. fibroblasts
c. Cystallins
d. hyaluronic acid
c. Crystallins
NOTE: alpha crystallins act as chaperones to reverse degradation of other crystallins. No collagen or fibroblasts within the lens. HA is present within the vitreous rather than lens
What is the predominant mechanism responsible for INC IOP in pts who are “steroid responders”?
DEC outflow facility
NOTE: not fully understood, the prevailing mechanism for an INC in IOP secondary to steroid use is that steroids INC deposition of glycoasminoglycans in the TM, resulting in reduced aqueous humor outflow
When does the critical period of visual develop extend from?
Birth to 9 years
NOTE: the critical period of development of the visual cortex is from birth to 7-9 years of age. The first 2-3 years of life are considered the most sensitive for development of the visual cortex
A frame has the dimensions 46-19-140 with an ED of 50 mm. The pt’s PD is 69 mm. What is the minimum lens blank size?
56 mm
MBL = ED + |(Frame PD - Pt PD)| + 2mm
A barber reclines his client’s chair toward a sink to wash his hair. When the barber turns on the water, it is very warm and gets into the client’s left ear. If the client has a normal response, the slow phase of the induced nystagmus will be in what direction?
RIGHT
A nystagmus is direction of the fast phase. In a normal, caloric testing with warm water in left ear will induce a left horizontal nystagmus, meaning the slow phase will be to the right.
What is the primary excitatory NT in the retina?
Glutamate
