3 - Dronka Flashcards
Anatomy
-lens capsule
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
Characteristics
- lens
- surgery
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
Types of capsular opacification
- anterior
- posterior
A: anterior capsular
P:
- fibrosis
- proliferation/pearl
- linear
- mixed
Anterior capsular opacification
- starts
- location is occurs
- complications (2)
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
Anterior capsular opacification
-incidence
—lens material (highest and lowest)
Highest
- silicone IOL with sharp optic edges
- plate haptic silicone design
Lowest
-acrylic IOL
Anterior capsular opacification
-disease (2)
Retinitis pigmentosa
Diabetes
Describe Soemmering’s ring
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
Posterior capsular opacification
-fibrosis form
Anterior epi cells form spindle-shaped fibroblasts -> migrate to PC
Pretty thick
Appearance
- white opacities
- fine folds
- wrinkles
Posterior capsular opacification
-proliferation/pearl form
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
Posterior capsular opacification
-mixed form
Combo of fibrosis and proliferation
Posterior capsular opacification
-linear form
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
Incidence and impact -PCO —how common —when occurs —who’s at higher risk
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
Incidence and impact
-PCO within 3mm zone affects (3)
High contrast sensitivity
Low contrast acuity
Psychophysical test results with differing degrees of sensitivity
-forward light scatter -> contrast sensitivity -> VA
Prevention of PCO
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
Treatment options
- previous
- new
P: surgical cutting/peeling, polishing posterior capsule
N: Nd:YAG 1064
Laser type
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
Contraindications
- absolute (2)
- relative (4)
A:
- corneal haze/pathology
- unable to hold steady/fixate
R:
- glass IOL
- active intraocular inflamm
- known/suspect CME
- high risk for RD
Complications
-IOP spike
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
Complications
-stromal haze/edema/endo cell count
2.3-7%
Can lead to Fuch’s dystrophy
-caution with energy into the eye
Complication
-CSME
0.55-2.5%
Within 3 weeks - 11 mo
Decr risk by incr time between ECCE and capsulotomy
-minimum time 3 mo
Complications
-IOL damage/pitting
—describe
—material
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
Complications
- RD
- retinal breaks
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
Complications
-endophthalmitis
Rare
Propionbacterium acnes endophthalmitis reported following capsulotomy
Presumed opportunity for organisms within capsule -> vitreous
Complications
-risk factors for RD
Higher total laser energy
Higher axial length (>24mm)
-avoid large capsulotomy in pts with high axial length
Candidates for YAG CAP
Vision 20/30 or worse
Symptomatic
-glare, blur, vision, contrast
> 3 mo post-op
Posterior capsulotomy -settings —energy —spot size —duration —pulses —amount of burns —offset
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
Posterior capsulotomy -pattern —cruciate —horseshoe —christmas tree —can-opener
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
Posterior capsulotomy
- marker shot
- treatment zone
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
Anterior capsulotomy -settings —energy —spot size —duration —pulses —amount of burns —pattern —offset
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
Anterior capsulotomy
-treatment pattern
Radial pattern at clock hours to release phimosis
If untreated, will tighten around the lens and create lens movement, astigmatism, etc.
YAG CAP follow up
- 1 day
- 1-2 weeks
High risk pts: high myopes, hx of severe infection
Check IOP, AC reaction, dilate
Post-op
-if pt RTC with secondary decreased vision
Assess for:
- refractive error shift
- CME
- RD
- glaucoma
- vitreous hemorrhage
