YAG Cap Flashcards
Capsule
Elastic membrane Barrier Permeable Reproducing -basal membrane of lens epithelium-anterior -basal membrane of elongating fiber cells-posteriorly Thickness -thickest near the equator -thinnest at post capsular poles
Lens
Surrounded by a capsule
- anteiror
- posterior
Surgery on lens
Anterior=capsulorhexis
Posterior=remains in tact to hold the IOL implant
-posterior capsular opacification. Growth and proliferation of lens epithelial cells from original cataract migrate on lens capsule
Anterior capsular opacification
Anterior capsular opacification
Posterior form of capsular opacification
Fibrosis
Proliferation
Linear
mixed
Anterior capsular opacification and anteiror capsule contracture syndrome
- starts by the 1st post op month-6 months
- occurs at the continuous capsulorhexis (CCC)
- complications: decenter IOL-multifocal IOL, MUST maintain good centration, lens title induced astigmatism
Incidence of anteiror capsular opacification nand antihero capsule contracture syndrome
Lens materials
- highest with silicone IOL with sharp optic edges and plate haptic silicone design
- lowest: acrylic IOL
Disease and anteiror capsular opacification and anteiror capsule contracture syndrome
RP ad DM
Soemmering’s ring
Looks like anteiror capsular opacification but ONLY OCCURS in APHAKIA
Results of anterior capsule edges attachment to the posterior capsule
- absence of IOL
- congential aphakia
- Lowe syndrome and hallerman-Streiff Francois syndrome
Fibrosis form of capsular opacification
- anterior epithelial cells form spindle shaped fibroblasts-migrate to PC
- appearance: white opacities, fine folds, wrinkles
Proliferation (pearl form) O.D. opacification
- pre-equatorial zone lens epithelial cells form swollen cells called bladder (or Wedl) cells-migrate to PC
- appearance: circular opacification, pearls (elschnig pearls)
Mixed form opacification
Combination of fibrosis and proliferation
Linear form of opacification
- PCO along persistent striae-create a channel allowing epithelial cells to bypass the barrier created by the square edge design of the IOL
- appearance: linear striae
Most common complication of cataract surgery
PCA
When doe PCA occur
30-50% within 3-5 years
Occurs within 20-26 months usually
Yougner patients and PCA
Highest risk
PCA within 3mm zone affects
High contrast sensitivity
Low contrast acuity
Psychophysical test resutls with differing degrees of sensitivity
-forward light scatter>contrast sensitivity>VA
Preventing PCO
- removal of all epithelial cells and cortical remnants
- lovage the intracapsular space with saline during surgery to denature residual epithelial cells
- clean the anterior chamber well with an irrigation dynamic pressure-assisted hydrodiessection tool
- pharmacological drops
Previous treatments for PCO
- surgical cutting or peeling
- polishing posterior capsule
New treatments for PCA
Nd:YAG 1064
Nd:YAG 1064
- pigment independent
- 4ns. Large amount of energy delivered in small spot size for brief time
photodisruptive:
- high light energy causes tissue to reduce to plasma
- disintegrates tissue
- no thermal or coagulation effect
- hydrodynamic waves and acoustics pulses travel back toward surgeon=OFFSET
Nd-YAG laser capsulatomy Sadie’s
Dilating drops
Use lenses
Half use steroid
Contraindications for yag cap
Absolute
- corneal haze or pathology
- unable to hold steady/fixate
Relative
- glass IOL
- active intraocular inflammation
- known/suspect CME
- high risk for RD
Most common complications of yag cap
IOP spike
Floaters
IOP spike in yag cap
-reduced faciltiy for aqueous humor outflow
—capsular debris
—acute inflammation cells
—liquefaction of the vitreous
—shock wave damage to TBM
->10mmHg in 15-67% of patients. Peaks at 3-4 hours but decreases after 24 hours
-associated with: glaucoma, capsuolotomy size, lack of IOL, sulcus fixation, energy, myopia, vitreoretinal Disease
Stromal haze/edema/decreased endothelial cell count in yag cap
- occurs in 2.3-7% of patients
- this can lead to Fuchs dystrophy depending on extend of damage
CSME and yag cap
- occurs in 0.55-2.5% of patients
- within 3 weeks-11 months
- decrease risk by increasing time between ECCE and capsulotomy
IOL damage/pitting and yag cap
Significant glare and image degradation
Minimal VA impact
Material complications and yag cap
Glass=fractures
PMMA=sustain cracks and central defects with radiating fractures
Silicone=blistered lesions and localized pits
Acrylic=white haze (highest risk of pitting)
RD and yag cap
- lifetime risk of RD after cat sx=1%
- lifetime risk of RD after capsuolotomy=additional 0.8-1.9%
- incidence: immediately to 1+ years
Retinal breaks and yag cap
Asymptatomic breaks found in 2.1% of patients within 1 month
Endophthlamitis and yag cap
- propionibacterium acnes endophthalmits reported following capsuolotomy
- presumed opportunity for organisms within capsule=vitreous
Nd:YAG energy levels for PCO 2015
474 consecutive eyes studied on several factors VERSUS total energy used
- complication rates
- type of PCA
- IOL material
- fixation of IOL
Analyzed for factors that led to complication
Incidence of IOP spike
12.9%
Uveitis incidence
9.9%
IOL pitting incidence
7.8%
CME incidence
2.9%
RD incidence
2.3%
Energy going in to the eye and complications
Less energy into the eye equal less complications
- the more energy and higher myopia=RD more likely
- pearl vs fibrosis: pearl were easier to clean off and fibrosis required more energy to get completely off. Using a lens will help concentrate the energy and decrease energy needed
- IOL material and fixation had no influence on issues with total energy use
Candidate for YAG cap
- Vision 20/30 or worse
- Symptomatic: glare, blur, vision, contrast
- > 3 months post op cataract surgery
Pre op yag cap
Psychophysical
- VA
- glare testing
- PAM
SLE IOP DFE/posterior segment evaluation (or B scan if unable to visualize fundus) Signed inform consent Vitals (BP, pulse)
posterior capsulotomy setting
- 1.3-1.8mJ
- spot size: fixed (8-11 microns)
- duration: fixed (4ns)
- pulses-1
- amount of burns: 10-40
- pattern: cruciate/horseshoe/Christmas tress/Can-opener (circular)
- Offset: +150 to +500 microns posteriorly
Cruciate
Top to bottom
Horseshoe
An upside down U from 7 clockwise to 5 o clock
Christmas tree
12 o’clock-4:30 and 12 o’clock to 7:30 without shots in central optical zone
Can opening )circular)
- creates large fragments that dont necessarily sink
- large floater within vision
Procedure for posterior capsuolotomy
- comfortable placement
- optional marker shot
- 1 drop tropicamide
- 1 drop alphagan 15-30m before
- 1 drop proparacaine OU
- focus on post cap (post offset)
- adjust energy PRN. Little/no tissue interaction=increase
- treat about 4mm in cruciate pattern (larger than undulated pupil). 10-40 total shots
Anterior capsulotomy setting
- 1.3-1.8mJ
- spot size fixed (8-11)
- duration: fixed (4ns)
- pulses: 1
- amount of burns: 10-40
- pattern: radial burns @ the clock hours
- offset: -150 to -500 microns ANTERIORLY
When would you make the treatemtn size smaller than the pupil in post yag cap
If they have a thick membrane. Creates a pinhole for them
Procedure for anteiror capsuolotomy
- comfortable placement
- 1 drop tropicamide
- 1 drop alphagan 15-30m prior
- 1 drop proparacaine OU
- focus on anterior phimosis (anterior offset)
- adult energy PRN
- treat in radial pattern @ clock hours to release phimosis. 10-40 total shots
Post op yag cap
- 1 drop alphagan
- recheck IOP 15-30m in office
- Rx PF QID x 7 days
FU for yag cap
1 day
-high risk patient
1-2 weeks
- check IOP
- check AC reaction
- dilation (r/o holes/tears/RD)
RTC 2m decreased vision and yag cap
Assess for
- refractive error shifty
- CME
- RD
- glaucoma
- vitreous hemorrhage
