BCSC 11. Lens & Cataract

Question 1

Rate of cataract surgery in developed countries

Answer 1

Up to 10,000 per million population per year

Question 2

Normal change in the human crystalline lens as it ages

Answer 2

Develops an increasingly curved shape, resulting in more refractive power

Question 3

How is metabolic waste removed from the crystalline lens

Answer 3

Aqueous humor

Question 4

Helmholtz Theory of accommodation

Answer 4

Most of the change in lens shape occurs at the central anterior lens surface

Question 5

Change that occurs in the Crystalline lens during terminal differentiation

Answer 5

Lens epithelial cells elongate into lens fibers

Question 6

Process that results in the formation of the Y sutures seen in the adult lens

Answer 6

Fusion of the embryonic cells within the fetal nucleus

Question 7

Common symptom of cortical cataracts

Answer 7

Glare under mesopic lighting conditions

Question 8

Lamellar membrane whorls seen on EM

Answer 8

Nuclear cataracts

Question 9

Cataract a/w chalcosis

Answer 9

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

Question 10

Cause of chalcosis

Answer 10

intraocular FB deposits copper in descemet membrane, anterior lens capsule or other intraocular basement membranes.

Question 11

Cataract occurs in galactosemia and posterior lenticonus

Answer 11

Oil droplet cataract

Question 12

Must perform this test if dense white cataract

Answer 12

B-scan ultrasonography to r/o RD, posterior staphyloma, occult tumor or posterior pathology that could affect visual outcome

Question 13

Determining factor for cataract surgery

Answer 13

Elective surgery - Impact of vision changes on patient’s daily activities and lifestyle

Question 14

Determining axial length with an immersion technique or contact applanation

Answer 14

IF significant corneal scarring, PSC, or vitreous hemorrhage

Question 15

Approach for eye with corneal guttae

Answer 15

Protecting corneal endothelium with coating agent, DISPERSIVE ophthalmic viscosurgical device (OVD)

Question 16

Best initial treatment of postoperative shallow anterior chamber caused by ciliary block glaucoma

Answer 16

Cycloplegia and aqueous suppression. If initial medical treatment fails, surgical disruption of vitreous face or vitrectomy at be necessary to restore normal aqueous circulation and AC depth

Question 17

Cause for severe intraoperative floppy iris syndrome (IFIS)

Answer 17

TAMSULOSIN - selective alpha-1-a adrenergic antagonist has greater effect on iris dilator muscle than nonselective

Question 18

Painless diffuse corneal edema and blurred vision within hours of surgery

Answer 18

Toxic anterior segment syndrome (TASS)

Question 19

Elevated IOP shortly after surgery causing decreased vision, pain, central epithelial edema “bedewing”

Answer 19

Retained OVDs

Question 20

IOL most likely to cause negative dysphotopsia

Answer 20

Square-edge posterior chamber IOL in capsular bag

Question 21

Indication for combined keratoplasty and cataract extraction

Answer 21

nuclear cataract and Fuchs endothelial dystrophy with vision worse in the morning - indicates significant corneal endothelial function

Question 22

Useful in IOL power calculation for patient with previous LASIK

Answer 22

Corneal topography

Question 23

IFIS after phacoemulsification has begun. Procedure to allow surgeon to best manage miotic pupil and floppy iris

Answer 23

Insertion of 4 or 5 iris hooks through new corneal incisions

Question 24

During phacoemulsification, surgeon realizes zonular dialysis of 3 clock-hours is present

Answer 24

Place a CTR, complete phacoemulsification, insert posterior chamber IOL. Risk of extending dialysis without capsular support

Question 25

Best procedure for cataract extraction in an eye with controlled uveitis and small pupil

Answer 25

Pupil stretching and lysis of any posterior synechiae, followed by phacoemulsification and placement of an acrylic IOL