Opthomology Basics Flashcards
What are the 4 types of refractive errors?
Hyperopia, Myopia, astigmatism, and presbyopia
A change in direction that occurs when a wave encounters the interface between two media
Refraction
What is snell’s law of refraction?
n1 sin θ1 = n2 sin θ2
n = index of refraction
When parallel rays are focused in front of the retina
-Secondary to longer eyes
Myopia
The correction for myopia is to push the focal point
Posteriorly
When parallel rays are focused behind the retina
-Secondary to shorter eyes
Hyperopia
The correction for hyperopia is to push the focal point
Anteriorly
Inability to see at near secondary to age related loss of elasticity of the focusing system
Presbyopia
The correction for Presbyopia is the same as for
Hyperopia
When light is not bent equally in all directions
Astigmatism
The correction for astigmatism is
Refraction
Age related change to the lens of the eye
-Results in clouding of the lens and decreased vision
Cataract
Glaucoma is a disease with which 3 cardinal components?
- ) Optic Nerve Damage
- ) Ocular Hypertension
- ) Visual Field Loss
Most people with glaucoma are managed by
Topical anti-hypertensive drops (B-blockers)
Inflammation of the soft tissue layer (conjunctiva) that overlies the eye
-Also known as pink eye
Conjunctivitis
What are the three types of conjunctivitis?
Infectious, allergic, and autoimmune
95% of the time, conjunctivitis is
-Treat with observation in most cases
Viral and bilateral
Inflammation of the uveal tissue, i.e. the iris, ciliary body, or choroid
Uveitis
Responsible for an estimated 10% of all cases of blindness in the US
Uveitis
The three main symptoms of uveitis are
Redness, pain, and photophobia
Treatment for uveitis is often
Topical steroids such as Durezol and prednisolone
Quick onset of action. Less risk of increase IOP and cataract. Systemic side effects
Oral prednisone
Leading cause of blindness in patients over 60 in developed nations
Macular degeneration
Loss of retinal pigment epithelial cells without RPE
Geographic Atrophy
Photoreceptor and choriocapillaris atrophies are seen with
Geographic atrophy
Marked by growth of new blood vessels
-Typically begins in the choroid and extends through a break in Bruch’s membrane
Neovascular (Wet) AMD
Can traverse the RPE and proliferate in the subretinal space as well
Neovascularization
The new blood vessels formed in neovascular AMD are
Abnormal (leak and bleed)
Induces blood vessel permeability and angiogenesis
VEGF
Important in many systemic functions including pregnancy, wound healing, remodeling of ischemic myocardium
VEGF
Intravitreal injection of receptor decoy fusion proteins, whole length antibodies, and fragmented antibodies
Anti-VEGF therapy
Key Finding: intensive glucose control reduces complications of DM
DCCT
What are the two main complications in the retina in diabetes patients?
Diabetic Retinopathy and Diabetic Retinal Swelling
What are the two characteristics of non-proliferative diabetic retinopathy?
Venous bleeding and IRMA
Characterized by a single or localized cluster of leakage sites
Focal Macular Edema
Typically seen in patients older than 65 years old
-Very uncommon in the young
Central Retinal Vein Occlusion (CRVO)
What percentage of individuals develop CRVO in the other eye within 5 years
5% are bilateral
Characterized by painless vision loss and hemorrhages in all 4 quadrants
CRVO
We see superficial flame memes and deep blot hemes with
CRVO
Most common in ages 60-70
-Risks are similar to CRVO
Branch Retinal Vein Occlusion (BRVO)
The typical site for BRVO is
Artery-vein crossings
Blood flow to the central retinal artery is blocked with
Central Retinal Artery Occlusion
With central retinal artery occlusion, we see severe irreversable
Vision loss
A characteristic of central retinal artery occlusion is
Ischemic retinal whitening with cherry red spot
A result of synchisis and syneresis
Posterior Vitreous Detachment (PVD)
The liquefaction of the vitreous gel and the formation of liquid-filled vacuoles
Synchisis
The collapse of the liquefied vitreous away from the retina
Syneresis
Refers to a group of inherited diseases that cause retinal degeneration
Retinitis Pigmentosa (RP)
Patients experience a gradual decline in vision as the photoreceptors degenerate
RP
With RP, rods are initially involved resulting in loss of
Night Vision and Peripheral Vision
The disorder is progressive and most people are legally blind by 40
RP
What is the treatment for RP?
Gene editing (CRISPR), Gene Therapy, and Artificial Vision
Optic nerve swelling secondary to increased pressure in the brain
Papilledema
