Refractive Surgery

Question 1

Radial Keratotomy

RK

Answer 1

uses diamond blade to make radial cuts deep into cornea to flatten it

Question 2

RK was used to treat….

Answer 2

myopia

Question 3

Problems with RK

Answer 3

permanently weakened cornea
unpredictable results
vision fluctuation
starbursts
not used

Question 4

Astigmatic Keratotomy

AK

Answer 4

arcing parallel cuts in periphery- steepen flatter and flatten steeper
often done during cataract surgery

Question 5

AK is used to treat….

Answer 5

high post-keratoplasty astigmatism

small degrees of pre-existing astigmatism

Question 6

Non- Contact Holmium uses…..

Answer 6

YAG laser

induces heat

Question 7

Non- Contact Holmium

Answer 7

places shrinkage spots outside visual axis to steepen cornea

Question 8

Non- Contact Holmium was used to treat….

Answer 8

hyperopia

Question 9

Problems with Non- Contact Holmium

Answer 9

induces astigmatism
high regression rate
not used anymore

Question 10

Conductive Keratoplasty

CK

Answer 10

radio frequency delivered to stroma by probe

predictable, safe, cheap

Question 11

Conductive Keratoplasty Use

Answer 11

low levels of hyperopia and presbyopia

Question 12

Contraindications for CK

Answer 12

pacemakers

Question 13

CK and Monovision

Answer 13

used on one eye so one for distance and one for near

Question 14

Laser Photoablation uses….

Answer 14

argon- fluoride gas

Question 15

Photorefractive Keratectomy

PRK

Answer 15

corneal epithelium removed

excimer laser photoablates anterior stroma to flatten or steepen cornea

Question 16

Indications of PRK

Answer 16

+3 to -6; -8 w/ mitomycin C
cornea too thin for LASIK
residual refractive error after cataract or refractive surgery
epithelial irregularities, EBMD, K scars

Question 17

Problems with PRK

Answer 17

significant postop discomfort- 2-3 days
slow vision recovery
subepithelial haze-more permanent with higher powers

Question 18

Mitomycin C

Answer 18

helps decrease haze in PRK

can cause corneal toxicity

Question 19

Laser in situ Keratomileusis

LASIK

Answer 19

flap created with microkeratome blade or femtosecond laser
photoablation in deep stroma
flap repositioned over ablated area

Question 20

Benefits of LASIK

Answer 20

deep stromal ablation results in less haze
no pain (epithelium intact) and almost instant vision

Question 21

Indications for LASIK

Answer 21

those prone to haze- -6D or more; significant astig
wanting immediate visual recovery
cant handle pain

Question 22

Problems with LASIK

Answer 22

loud clicking and burning smell from gas (not burning)
flap complications
epithelial growth under flap
corneal ectasia if cut too thin

Question 23

Contraindications of LASIK

Answer 23

epithelial irregularities- EBMD and scars

Question 24

Thickness required for LASIK

Answer 24

250 micrometers remaining of stroma
100 for flap
12 x each D
added cannot be greater than central corneal thickness

Question 25

Laser Subepithelial Keratectomy | LASEK

Answer 25

alcohol loosens epithelium, which is folded back for photoablation and rolled back after like PRK but faster recovery and less discomfort

Question 26

Epithelium in LASEK

Answer 26

most dies as a result of alcohol

Question 27

Epithelial Laser in situ Keratomileusis | epi-LASIK

Answer 27

like LASEK but flap made with microeratome- less epithelial toxicity and more viable

Question 28

Best refractive surgery for <6D of myopia

Answer 28

PRK

Question 29

Best refractive surgery for 6 - 10D of myopia

Answer 29

LASIK | less risk of haze

Question 30

Phakic Intraocular Lenses

Answer 30

artifcial lenses inserted into eye to correct higher refractive error placed in anterior or posterior chamber

Question 31

Artisan Lenses

Answer 31

pIOL clipped on to front of iris

Question 32

Advantages of pIOL

Answer 32

>20D of hyperopia or myopia 7.5D of astigmatism reversible maintains accommodation

Question 33

Disadvantages of pIOL

Answer 33

min AC depth of 3.2mm- rules out most hyperopes endothelial cell loss or cataract formation from rubbing potential for glaucoma

Question 34

Refractive Lens Exchange

Answer 34

replaces actual lens with fake one to correct refractive error

Question 35

Advantages of RLE

Answer 35

spherical corrections +20 to -30D available in toric, multifocal, accommodating no need for later cataract surgery

Question 36

Disadvantages of RLE

Answer 36

loss of accommodation | high myopes at risk of RD

Question 37

pIOL vs RLE

Answer 37

pIOL safer and better for non-presbyopes | RLE better for high hyperopes w/ shallow AC and those needing cataract surgery soon

Question 38

CK Post-Op Presentation

Answer 38

FB sensation and tearing functional vision next day, can go back to work astigmatism worse in 1st month effects regress 1D every 2-3 yrs

Question 39

Mx PRK

Answer 39

repithelialization takes ~3 days- discomfort and lack of functional vision, wear BCL vision fluctuates until about 6 months

Question 40

LASIK Post-Op Presentation

Answer 40

no discomfort, good vision in 24 hours vision stabilizes after 3 months watch for flap complications