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Z Lasers - Final > 3 - Dronka > Flashcards

3 - Dronka Flashcards

1
Q

Anatomy

-lens capsule

A

Elastic membrane

Barrier

Permeable

Reproducing

  • basal membrane of epith -> anteriorly
  • basal membrane of elongating fiber cells -> posteriorly

Thickness

  • thickest at equator
  • thinnest at post capsular poles
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2
Q

Characteristics

  • lens
  • surgery
A

Surrounded by capsule (ant and post)

Anterior = capsulorhexis
Posterior = remains intact to hold IOL implant
-PCO: growth and proliferation of lens epi cells from original ct migrate on lens capsule

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3
Q

Types of capsular opacification

  • anterior
  • posterior
A

A: anterior capsular

P:

  • fibrosis
  • proliferation/pearl
  • linear
  • mixed
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4
Q

Anterior capsular opacification

  • starts
  • location is occurs
  • complications (2)
A

Starts by 1st post-op month -> 6 weeks

Occurs at continuous curvilinear capsulorhexis (CCC)

Decenter IOL
-multifocal IOL: must maintain good centraiton
Lens tilt
-induces astigmatism

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5
Q

Anterior capsular opacification
-incidence
—lens material (highest and lowest)

A

Highest

  • silicone IOL with sharp optic edges
  • plate haptic silicone design

Lowest
-acrylic IOL

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6
Q

Anterior capsular opacification

-disease (2)

A

Retinitis pigmentosa

Diabetes

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7
Q

Describe Soemmering’s ring

A

Looks like anterior capsular opacification, but ONLY IN APHAKIC patients

  • absence of IOL
  • congenital aphakia
  • Lowe syndrome, Hallermann-Streiff-Francois syndrome

Result of ant capsule edges attachment to posterior capsule

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8
Q

Posterior capsular opacification

-fibrosis form

A

Anterior epi cells form spindle-shaped fibroblasts -> migrate to PC

Pretty thick

Appearance

  • white opacities
  • fine folds
  • wrinkles
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9
Q

Posterior capsular opacification

-proliferation/pearl form

A

Pre-equatorial zone lens epi cells form swollen cells, called bladder or Wedl cells -> migrate to PC

Appearance

  • circular opacification
  • Elschnig pearls = almost jelly-like, easy to blast thru
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10
Q

Posterior capsular opacification

-mixed form

A

Combo of fibrosis and proliferation

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11
Q

Posterior capsular opacification

-linear form

A

PCO along persistent striae -> creates channel, allowing epi cells to bypass the barrier created by the square-edge design of the IOL
-little burrows = looks like the lens is cracked

Appearance
-linear striae

Can cause visual distortion

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12
Q 
Incidence and impact
-PCO
—how common
—when occurs
—who’s at higher risk
A

Most common complication of ct sx

Occurs days-years post-op

  • b/w 30-50% within 3-5 years
  • average 2-3 mo

Younger pts at higher risk
-cells regenerate faster/body works more effectively

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13
Q

Incidence and impact

-PCO within 3mm zone affects (3)

A

High contrast sensitivity

Low contrast acuity

Psychophysical test results with differing degrees of sensitivity
-forward light scatter -> contrast sensitivity -> VA

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14
Q

Prevention of PCO

A

Removal of all epi cells/cortical remnants

Lavage the intracapsular space with saline during surgery to denature residual epi cells

Clean AC well

Implanting IOL

Pharmacological drops
-stops mitosis - binds tubulin and inhibits formation of microtubules

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15
Q

Treatment options

  • previous
  • new
A

P: surgical cutting/peeling, polishing posterior capsule

N: Nd:YAG 1064

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16
Q

Laser type

A

Nd:YAG 1064:
pigment independent

4 nanoseconds
-large amount of energy in small spot size for brief time

photodisrupive = shock wave
-high light energy causes tissue to reduce to plasma
-disintegrate tissue
-no thermal/coag effect
-hydrodynamic waves and acoustic pulses travel back toward surgeon
—focal point must be posterior to target tissue =offset

17
Q

Contraindications

  • absolute (2)
  • relative (4)
A

A:

  • corneal haze/pathology
  • unable to hold steady/fixate

R:

  • glass IOL
  • active intraocular inflamm
  • known/suspect CME
  • high risk for RD
18
Q

Complications

-IOP spike

A

Most common besides floaters

Reduced facility for AH outflow
-debris, acute inflamm cells, liquification of vitreous, shock wave damage to TM

> 10mmHg

  • peaks at 3-4 hours
  • decreases, but may remain elevated for 24 hours, returns to baseline in 1 week

Assoc with: glaucoma, capsulotomy size, lack of IOL, sulcus fixation, energy, myopia, vitreoretinal disease

19
Q

Complications

-stromal haze/edema/endo cell count

A

2.3-7%

Can lead to Fuch’s dystrophy
-caution with energy into the eye

20
Q

Complication

-CSME

A

0.55-2.5%

Within 3 weeks - 11 mo

Decr risk by incr time between ECCE and capsulotomy
-minimum time 3 mo

21
Q

Complications
-IOL damage/pitting
—describe
—material

A

Significant glare and image degradation
-problem if hemibeams are not in contact/are out of focus

Minimally impacts VA

Glass = fractures
PMMA = sustain cracks, central defects with radiating fractures
Silicone = blistered lesions, localized pits
Acrylic = white haze, looks like a little cataract, highest risk of pitting
22
Q

Complications

  • RD
  • retinal breaks
A

RD:
Lifetime risk after cataract surgery = 1%
After capsulotomy = 2%

Occurs immediately or 1+ years

RB: asymptomatic breaks found in 2.1% within 1 mo

23
Q

Complications

-endophthalmitis

A

Rare

Propionbacterium acnes endophthalmitis reported following capsulotomy

Presumed opportunity for organisms within capsule -> vitreous

24
Q

Complications

-risk factors for RD

A

Higher total laser energy

Higher axial length (>24mm)
-avoid large capsulotomy in pts with high axial length

25
Q

Candidates for YAG CAP

A

Vision 20/30 or worse

Symptomatic
-glare, blur, vision, contrast

> 3 mo post-op

26
Q 
Posterior capsulotomy
-settings
—energy
—spot size
—duration
—pulses
—amount of burns
—offset
A

energy: 1.3-1.7mJ

spot size: fixed 8-11 microns

duration: fixed 4 nanoseconds
pulses: 1

amount of burns: 10-40

offset: +150 to +500 microns posteriorly

27
Q 
Posterior capsulotomy
-pattern
—cruciate
—horseshoe
—christmas tree
—can-opener
A

Cru: superior -> inferior

H: upside-down U from 7:00 to 5:00

ChT: 12:00 to 4:30 and 12:00 to 7:30, no shots in central optical zone

Can: circular, large floater within vision

28
Q

Posterior capsulotomy

  • marker shot
  • treatment zone
A

Optional shot
Use with off-center pupil or to tell where the center of their pupil is for LOS

~4mm cruciate pattern (larger than undilated pupil)
-if make is smaller, get PH effect = do for really severe/thick

29
Q 
Anterior capsulotomy
-settings
—energy
—spot size
—duration
—pulses
—amount of burns
—pattern
—offset
A

energy: 1.3-1.8mJ

spot size: fixed 8-11 microns

duration: fixed 4 nanoseconds
pulses: 1

amount of burns: 10-14

pattern: radial burns at the clock hours
offset: -150 to -500 microns anteriorly

30
Q

Anterior capsulotomy

-treatment pattern

A

Radial pattern at clock hours to release phimosis

If untreated, will tighten around the lens and create lens movement, astigmatism, etc.

31
Q

YAG CAP follow up

  • 1 day
  • 1-2 weeks
A

High risk pts: high myopes, hx of severe infection

Check IOP, AC reaction, dilate

32
Q

Post-op

-if pt RTC with secondary decreased vision

A

Assess for:

  • refractive error shift
  • CME
  • RD
  • glaucoma
  • vitreous hemorrhage

Z Lasers - Final (4 decks)

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