Lens & Cataract

Question 1

eye with extreme increased axial length susceptible to this issue

Answer 1

lens-iris diaphragm repulsion syndrome (LIDRS)

reverse pupillary block and AC deepens

Question 2

Where is the germative zone of the lens epithelium located?

Answer 2

immediately anterior to the lens equator

Question 3

oily rings of debris aroudn the lashes “collarettes” are hallmark for this and RF for surgery

Answer 3

blepharitis and meibomianitis

endophthalmitis

Question 4

Reduces PCO formation in acrylic foldable IOL

Answer 4

truncated or square-edge optic design

Question 5

best describes viscosity of an OVD

Answer 5

resistance to flow; thickness or thinness of a fluid

Question 6

Cohesive OVD

Answer 6

long-chain, high MW, high viscosity

maintain space well at no or low shear rate, displaced at high shear rates

easier to remove from eye because they stick together (spaghetti)

minimal coating (less protection)

Question 7

Optical characteristics of human lens with age

Answer 7

increasing anterior and posterior curvature

decrease index of refraction

(increased index of refraction in NSC)

Question 8

Type of cataract characteristic of ischemic ocular conditions eg Takayasu arteritis, Buerger disease, anterior segment necrosis

Answer 8

posterior subcapsular

Question 9

lens with higher rates of capsular opacification

Answer 9

round edge

Question 10

Lens has higher level of what compared to surrounding aqeous and vitreous

Answer 10

K+

amino acids

Question 11

This patient c/o glare and vague shadow (double) image. Cause of this problem?

Answer 11

Capsular rupture

Question 12

Association explains patient’s disorder for abnormality shown

Answer 12

anterior subcapsular cataract a/w atopic dermatitis

cataract formation in 25% (2nd and 3rd decade) resemble shield like plaques

Question 13

type of IOL most likely to cause negative dysphotopsia

Answer 13

square-edge posterior chamber IOL in the capsular bag

Question 14

Decentered PC IOLs of all types cause this

Answer 14

positive dysphotopsias

Question 15

Thickness at each portion

Answer 15

A - 14 um

B - 21 um

C - 17 um

D - 23 um

E - 4 um

Question 16

88 yo F p/w pain and redness, VA HM

Diagnosis

Answer 16

phacolytic glaucoma

often large white particles seen in AC

(note: not phacoantigenic

Question 17

Medication that caused this complication

Answer 17

Afluzosin (alpha 1 adrenergic antagonist)

(floppy iris syndrome RF for intraoperative iridodialysis)

Question 18

Changes occur to lens epithelial cells during terminal differentiation

Answer 18

increase in cell protein content and loss of organelles

Question 19

MC cataract in RP

Answer 19

PSC

Question 20

RF a/w intraoperative choroidal hemorrhage

Answer 20

Glaucoma

HTN

tachycardia

obesity

high myopia

anticoagulation

advanced age

chronic ocular inflammation

(Note: younger age reduces risk)

Question 21

What percentage of lens glucose passes through the citric acid cycle?

Answer 21

3%

Question 22

Change in lens and zonule when ciliary muscle contracts?

Answer 22

the equatorial diameter of the lens decreases

diameter of muscle ring reduced

zonular tension decreases

axial thickness of lens increases

dioptric power increases

Question 23

OVD that maintains volume and expels easily

Answer 23

cohesive

Question 24

Management intraop for patient with numerous corneal guttae

Answer 24

increase use of dispersive OVD during phacoemulsification

Question 25

molecular activity in crystalline lens that is most a/w development of age-related nuclear sclerosis

Answer 25

**formation of protein-to-glutathione disulfide bonds** proteins aggregate to become large particles that are water-insoluble and scatter light

Question 26

cataract a/w chalcosis

Answer 26

sunflower cataract petal-shaped deposition of yellow or brown pigment in lens capsule that radiates from anterior axial pole of lens to equator

Question 27

after hydrodissection, anterior movement of entire iris-lens diaphragm and collapse of AC. No pain and high IOP

Answer 27

posterior fluid misdirection syndrome

Question 28

enzyme that protects lens from free radical or oxidative damage

Answer 28

**superoxide dismutase** (catalyzes destruction of superoxide anion O2- and prodcues H2O2) Others: catalase, glutathione peroxidase

Question 29

s/p cataract surgery, patient requires unexpectedly large myopic over-refraction. Etiology?

Answer 29

capsular block (distention of capsular bag - forward displacment of lens optic results in myopic shift) Tx with Nd:YAG which releases posterior fluid

Question 30

Patient is at increased risk for what s/p CE+IOL

Answer 30

posterior capsular opacification

Question 31

POM3 myopic change of -2.00. Cause?

Answer 31

**capsular contraction** RF small capsulorrhexis, abnormal or asymmetric zonular support, silicone plate haptic IOL

Question 32

CE in an eye with controlled uveitis

Answer 32

phaco and placement of acrylic IOL in capsular bag

Question 33

Diagnosis and expected complaint?

Answer 33

"oil-droplet" cataract monocular diplopia

Question 34

Developmental process results in formation of Y-sutures

Answer 34

fusion of embryonic cells within the fetal nucleus

Question 35

Lens abnormality

Answer 35

**anterior polar cataract** (note: mittendof dot is on posterior lens capsule, inferonasal)

Question 36

greatest RF for phimosis syndrome

Answer 36

**pseudoexfoliation syndrome** (marfan syndrome, small cpasulorrhexis, silicone IOL)

Question 37

systemic medication most likely to cause severe intraoperative floppy iris syndrome

Answer 37

**tamsulosin** (SELECTIVE alpha 1a adrenergic antagonist) Note: Nonselective - afluzosin, doxazosin, terazosin

Question 38

average amount of IOP lowering effect expected from phaco + IOL implantation in eye with high IOP

Answer 38

10%-34% lowering of IOP

Question 39

histology of PSC

Answer 39

posterior migration of lens epithelial cells

Question 40

Strongly a/w what factor during cataract surgery

Answer 40

**pseudoexfoliation** progressive capsular contration or capsular phimosis (complete phimosis of anterior capsular opening)

Question 41

clinical feature would increase suspicion that a patient has a traumatically dislocated or subluxed crystalline lens

Answer 41

imparied accomodation

Question 42

light a/w this type of cataract

Answer 42

cortical

Question 43

RF for NSC cataract

Answer 43

smoking and statins

Question 44

rate-limiting step in glucose phosphorylation

Answer 44

hexokinase reaction

Question 45

carbohydrate metabolism change with high glucose

Answer 45

aldose reductase activity increases

Question 46

pigmentary mottling of macula 3 weeks after exposure

Answer 46

microscope-induced light toxicity

Question 47

intraoperative adjustment if excessive postocclusion surge noticed

Answer 47

**reduce maximum vacuum setting**

Question 48

Lens change after hyperbaric oxygen

Answer 48

**_nuclear cataract_** myopic shift

Question 49

Tx ciliary block glaucoma

Answer 49

**cycloplegia with atropine and aggresive aqueous suppression with topicals and hyperosmotics (oral glycerin IV mannitol)** AVOID MIOTICS (if necessary) Nd:YAG iridozonulohyaloidotomy vitrectomy