Pathology, Evaluation and Management Flashcards
cause of presbyopia
lens hardening
relative lens cytoplasmic concentration of glutathione, potassium, sodium, and calcium as we age?
glutathione and potassium decrease
sodium and calcium increase
what is “second sight?”
ability of hyperopic patient to read without spectacles after a myopic shift caused by a cataract
nuclear cataracts affect distance or near vision more?
distance
brunescent cataract?
advanced nuclear cataract that is very brown and opaque
first signs of cortical cataract
vacuoles and water clefts in posterior cortex
opacification of the entire cortex from the capsule to nucleus? swelling of this cataract?
mature cortical cataract; intumescence
wrinkled and shrunken capsule in cortical cataract? free moving nucleus in liquefied cortex?
hypermature; morgagnian
which major class of adult cataract is generally seen in younger patients?
PSC
PSC presenting symptoms?
glare and decrease vision in bright light (miotic conditions)
pathophys and histology of PSC?
posterior migration of enlarged lens epithelial cells, which histologically are called Wedl, or bladder, cells
lens changes with the following drugs:
- steroids
- phenothiazines
- anticholinesterases
- amiodarone
- statins
- tamoxifen
- PSC
- ASC
- ASC
- stellate pigment deposition in anterior cortical axis
- DECREASED rate of nuclear cataract
- no effect
name of annular pigment deposition on anterior lens capsule following blunt trauma?
Vossius ring
common appearance of traumatic cataract from blunt force?
stellate opacity in axial location
early anterior segment findings of siderosis bulbi?
heterochromia and yellowish anterior lens capsule discoloration
first sign of cataract from electrical injury
vacuoles in anterior midperiphery
location of deposition in chalcosis?
(copper) Descemet’s (Kayser-Fleischer ring) and anterior lens capsule, leading to a “sunflower cataract,” which usually is not visually significant
snowflake cataract
acute, bilateral, widespread subcapsular lens opacification, usually in a young patient with uncontrolled diabetes
oil droplet cataract: cause and inheritance
galactosemia; AR
differential for christmas tree cataract? Inheritance and findings in the inherited cause?
Hypoparathyroidism and Myotonic dystrophy (AD; low IOP from presumed ciliary body detachments, ptosis, delayed relaxation of controlled muscles, cardiac conduction delays, frontal balding)
food that can decrease cataract formation?
eating cooked spinach twice a week
cause of smoking and excessive alcohol intake on the lens? any affect from smokeless tobacco products?
nuclear cataracts. yes (also nuclear cataracts)
affect of vitamins C and E and beta carotene on cataract formation in AREDS?
no effect
type of cataract in Fuchs heterochromic iridocyclitis? how common?
cortical; 70%
most common overall cataract in uveitis
PSC
type of cataract post vitrectomy? etiology?
nuclear. increased intra- and post-operative oxygen tension
refractive change cause by hyperbaric oxygen treatment? cataract formation? threshold for cataract?
myopic shift, due to nuclear sclerosis. 150 times in a 1 year period
tissues affected by pseudoexfoliation syndrome? ocular complications?
all over the body (not limited to eye). capsular weakness, zonular fragility and possibly spontaneous lens subluxation, pigmented TM leading to POAG
cataract in atopic dermatitis? when do these present?
ASC opacities resembling shield-like plaques; usually appear in teens or twenties
pacoantigenic v phacolytic v lens particle v phacomorphic glaucoma
phacoantigenic: severe zonal granulomatous inflammation related to retained cortex or leakage of lens particles from traumatized capsule
phacolytic: noninflammatory condition caused by the ingestion of lens particles, which have leaked out of an intact capsule in the setting of a mature cataract, by macrophages that can clog the TM
lens particle: retained lens material after surgery or trauma where lens material directly blocks TM
phacomorphic: intumescent lens causes pupillary block or anterior displacement of lens-iris diaphragm
which wavelengths undergo more scatter by cataractous lenses?
short (blue)
which eye to operate on first?
usually most visually significant. may take into consideration which eye is dominant. also may do better eye first if patient is very sick and might not make a second operation
management of blood thinners and diabetic meds prior to ocular surgery?
blood thinners are generally not discontinued. if desired, warfarin should be stopped 3-5 days in advance, and aspirin 10-14 days
hold all oral hypoglycemics and short acting insulins, and only take half of long acting insulin the morning of surgery
cutoff for acceptable difference in axial length between two eyes in the absence of pathology?
0.3 mm
principles of A-scan. affect of silicone oil?
measures axial length by the time it takes ultrasound waves to travel through ocular structures with presumed velocity values through each structure. ultrasound travels more slowly through silicone oil and thus it will take longer for sound waves to travel, leading to an overestimation of axial length.
what may cause errors in values obtained by optical biometers?
corneal scar, dense PSC, vit heme
SRK formula
P = A - 2.5L - 0.9K
P = power, A = A constant of specific lens, L = axial length, K = average keratometric reading in diopters
RK patients generally have what type of refractive surprise after cataract surgery?
undercorrection (hyperopia)
formula for hard contact lens overrefraction in estimation of corneal power of post RK eye
K = conact lens base curve + contact lens power + overrefraction - MRx done without conact
strongest modifiable risk factor for the development of cataracts?
smoking
