Lens and Cataract Flashcards
WAGR
Wilms Tumor
Aniridia
GU abnormal
Retardation
A/w sporadic aniridia (1/3)
A/w PAX6 mutation (also post embryotoxon, Peters, Axenfeld, and congenital cataract)
Aniridia high risk of glaucoma
cloudy cornea at birth
STUMPED Sclerocornea; Trauma Ulcer; mucopolysaccharidosis Peters; Endothelial(CHED) Dermoid
calculate cornea power for post refractive sx pt
-Historical method=Pre-op K + (Preop spherical equivalent - postop SE refraction)
-Contact Lens method
-Topography method
#Post myopic sx – overestimate cornea power – lead to hyperopic surprise
post hyperopic sx – under – myopic surprise
Hypermature cataract –> Morgagnian cataract
Intumescent cataract
Cerulean cataract
Intumescent cataract- swelling inside cataract with abundant amount of water
Cerulean cataract-Bluish opacity, N.V.S. AD type congenital cataract
trauma contusion cataract
Posterior star-like cat
Peters anomaly
failure of lens vesicle properly separate from surface ectoderm
pre-op stop coumadin or ASA/Plavix (clopedogrel) /Vit E
coumadin 3-5 days
ASA/clopedogrel / Vit E - 10 days
SRK formula
P=A-2.5L-0.9K
most common congenital cataract
lamellar
lens dislocate: ectopia lentis
Marfan’s: 50-80% develop
Homocysteinuria
Marfan’s: superotempral; abn fibrillin; brittle zonule;
Homocysteinuria: inferonasal; retardation and tall; thromboembolic risk with general; low methionine and high cysteine diet, Vit 6 supplement
Glaukomflecken
grey-white anti subcapsular opacity
Forster-Fuchs spot
RPE hyperplasia with high myopia (response to CNV does not progress)
AREDS2 change
add lutein + zeaxanthin, long chain polyunsaturated fatty acid (DHA and EPA), or both taking out beta carotene, lower zinc dose, or both #Study suggest substitute beta carotene with lutein + zeaxanthin
Highest MW?
alpha cystallin
betagamma
gamma
Alpha: Hight MW
betagamma: represent majority weight 55%
gamma: minority cystallin by weight
The wait time for dropped nucleus in the vitreous without CME
3 weeks
Vossius ring
trauma compress iris against lens, circular pig deposit
phacolytic glaucoma
vs
phacoanaphylactic (phacoantigenic) uveitis
phacolytic glaucoma: lens material leak through capsule–macrophage–clog TM
vs
phacoanaphylactic (phacoantigenic) uveitis: bag violated causing inflammation
obese, thick-neck pt
COPD pt
pt prone to Valsalva (full bladder, constipation):
Pos or Neg posterior pressure
Positive vitreous pressure – shallow AC
most mitotically active lens epithelial cell
anterior pre-equatorial capsule
How does Crystalens work?
by changing the position in the bag
PSC cataract
Commonly a/w DM
Myotonic dystrophy develop PSC after “Christmas tree” cataract
remnant of:
Bergmeister’s pupillae
Mittendorf’s dot
iris strand
B- hyaloid a. (connect optic disc to fetal lens)
M- tunica vasculosa lentis
I- anterior pupillary membrane
photostress recovery time:
macular disease or ON?
Macular:
time require to see one line above pre-test vision. >30 sec abn
Anti or post Lenticonus
with Alport’s
lenticonus more common of posterior and unilateral
when anterior and bilateral – Alport’s ( also a/w kidney dis) – also appears “oil droplet” by retroillumination
“oil droplet” b/l cataract in pt of first few weeks of life
Galactosemia
AS inherited
inability covert galactose to glacose. MC also severe form- classic galactosemia by defect in Gal-1-PUT
eliminate milk products
-malnutrition, hepatomegaly, jaundice and retardation.
Brown-McLean syndrome
peripheral circumferential edema starting from inferiorly without central invovle; 6-16 years following intracap cataract surgery.
Central corneal guttata; punctate orange-brown pigment on endothelium underlining edematous cornea
Restor multifocal lens work by?
diffraction and refraction
What is:
Temporal (pseudophakic) dysphotopsia?
Positive: stars, flashes, streak of lights, halos
Neg: shadow
most common due to square-edge designed lens or
of high index material
10-20% cataract surgery pt
-reassurance; alphagan P or pilo; glasses with thicker frame; piggyback lens; nasal anterior lens capsule removal by Yag; reverse optic capture; IOL exchange
PREVENTION: capsulorhexis rim overlaps lens edge; round-edge with lower index material; IOL well centered; optic-haptic junction horizontally oriented.
TASS
Toxic Anterior Segment Syndrome
TASS 12-24 hr postop (mgmt: control inflammation and IOP)
Endophthalmitis 2-7 days
Lens derives from what germ layer
ectoderm
Fuchs’ heterochromic iridocyclitis (FHIC)
a/w Amsler sign
FHIC is a type of chronic uveitis that is associated with long and fragile vessels that cross the angle and insert high in the angle. Because of their high insertion, they are frequently (25% of cases) nicked when entering the anterior chamber with a keratome, resulting in intra- or post-operative hyphemas. This is why a more anterioriy-placed phaco wound is recommended in these patients. “Amsler sign” is the term given for the bleeding that occurs secondary to nicking these blood
vessels.
Other key features of FHIC include: • typically unilateral • typically without severe pain or photophobia (unlike other forms of uveitis) • “stellate” (star-configuration) keratic precipitates (KP) that are evenly scattered across the endothelium (in contrast to other forms of uveitis where the KP are located more inferioriy); these
KP are also small/medium-sized and white • iris heterochromia (involved blue eyes appear darker; involved brown eyes appear lighter) • lack of anterior or posterior synechiae • high incidence of posterior subcapsular cataract (75%) • dffficutt to control gjaucoma (i.e. if a FHIC eye has glaucoma, it usually requires surgical glaucoma treatment for adequate control)
Lastly, unlike other forms of chronic iridocyclitis. It is not necessary to treat the inflammation in FHIC. This is because the inflammation is not typically associated with the usual uveitic complications (e.g. anterior/posterior synechiae, cystoid macular edema, severe eye pain/photophobia, etc). Most of the management of FHIC focuses on glaucoma screening/management and cataract removal.
Germinative zone
which is pre-equatorial zone (post to ant cap) and reside cuboidal epi cells, move to equator where they begin to differentiate to lens fiber, complete at “bow region” (post-equatorial zone)
lens energy production
-5% aerobic glycolysis pathway
-78% anaerobic
-5% HMP
DM – sorbital pathway
Weill-Marchesani syndrome
microspherophakia (faulty development of 2nd lens fibers) causing pupillary block angle closure glaucoma
-tx with cycloplegics (also PI)
syn: short stature, short and stubby fingers, broad hand w/ reduced joint mobility. Either isolate (AR) or a/w Peters, Marfan, Alport, Lowe or congenital rubella.
