Refractive Surgery Pre-&Post-op Flashcards
1
Q
What are the refractive surgery procedure options?
A
- Laser Vision Correction (LVC)
- Implantable Collamer Lens (ICL/Phakic IOL)
- Refractive Lens Exchange (RLE)
2
Q
When should optom discuss refractive surgery procedure?
A
- Px seeking alternative to spex or CLs
- Visual options:
o Spex
o CLs
o Refractive surgery (LVC/Phakic IOL/RLE)
3
Q
What are the ranges for the type of refractive surgery?
A
ICL/Phakic IOL: spherical +20->-20DS and astig up to 6DC
RLE: +20->-20DS, up to 10DC
LASEK/LASIK: +4->-12DS, -6DC
4
Q
What happens at refractive consultation?
A
In H&S need to establish motivation for surgery and for CL wearers – need to leave these out for 7 days before surgery
Rx needs to be stable
All pxs are dilated
Idesign – aberrometer that records px’s Rx
Specular microscope applies more to pxs going for refractive lens exchange – tells about corneal endothelium & its regularity
IOL master tells which power of lens is best suited to px in refractive lens exchange
5
Q
What are the factors optom should take into consideration - refractive surgery?
A
- LVC – residual stromal bed (RSB)
- LASIK >480 microns (CCT)
- LASEK >450-480 microns (CCT)
- Post-surgery the corneal tissue thickness is referred to as residual stromal bed – how much tissue is left after the prescription has been removed
o For LASIK the minimum tissue thickness must be >250microns
o For LASEK the minimum tissue thickness must be >350microns - In most cases, optom needs to calculate to ensure px has enough tissue thickness to proceed w/ surgery
6
Q
What are the discussions needed on refractive procedure and outcomes?
A
- Visual outcomes: distance & near (presbyopia) – px will need reading glasses
- Risks: infection/inflammation/poorer outcomes
- Regression – Rx may come back a little bit, px needs made aware they need glasses in future
- Further surgery (LVC enhancement (fine-tuning)/cataract development/YAG laser)
- Consent – surgeon, ophthalmologist, px declaration – surgeons decision is final on any procedure
7
Q
Describe laser vision correction?
A
- Involves reshaping cornea by removal of corneal tissue, to reduce or eliminate need for specs or CLs
- Most commonly performed LVC procedures are LASIK and LASEK
- Hyperopia to +4, myopia to -12 and astigmatism to -6DC
8
Q
Describe LASIK - protective flap?
A
- First step is creating protective flap, this is then lifted and second step is applying laser to corneal tissue below flap, laser reshapes corneal tissue to remove px’s Rx
- Femtosecond laser is modern day method of creating protective LASIK flap
- Flap thickness created by IntraLase is typically thinner than that for mechanical microkeratomes
- Benefits of using IntraLase:
o Thinner flap
o More uniform thickness of flap
o Laser is more accurate - IntraLase Femtosecond laser: flap thickness is 100 to 120µm
- Microkeratome – historic technology: flap thickness is 160µm
9
Q
What is IntraLase Photodiruption - IFS150?
A
- A pulse of laser energy is focused to a precise spot inside cornea - 120µm deep
- Microplasm is created, vaporising ~1 micron of corneal tissue
- This one micron of corneal tissue then expands, a bubble of gas and water is then created which separates the corneal lamellae
- A cleavage plane is then created in cornea, the by-products of photodisruption (CO2 & water) are absorbed by mechanism of endothelial pump, leaving this cleavage plane in the cornea
- This whole process is then repeated at many points – the pulse of lasers is focussed individually at many different points & photodisruption can occur which will create a cleavage plane
- Gas & water are absorbed or liberated when corneal flap is lifted
- The photodisruption process allows cleavage plane to be created horizontally and vertically (helps to create protective flap on front surface of cornea)
o Laser pulses can be stacked on each other to create a vertical cleavage plane
10
Q
What is the LASIK procedure?
A
- Cornea is anaesthetised & lid speculum inserted to keep eyelids away and stop px blinking
- A suction ring is applied to limbus to create an immobile cornea
- Flap is created by IntraLase laser (as described above)
- Flap is lifted to expose stromal bed, the hinge most often being paced at 12’clock (superior position)
- Eye tracker is engaged & excimer laser is applied to remove Rx
- Flap is washed with balance salt solution, replaced & edges are smoothed down
11
Q
What is the LASEK procedure?
A
- Cornea is anaesthetised & lid speculum inserted
- 18% ethanol is applied to cornea in corneal ring for around 30secs to loosen & soften epithelium
- Edge of loosened epithelium is lifted with surgical instrument
- Stromal bed is exposed & laser is applied immediately to remove Rx
- Epithelium is replaced (procedure becomes PRK if epithelium is discarded)
- Bandage CL is applied which is removed by Optometrist between day 3-5
o Bandage CL makes eye feel more comfortable & prevent air from hitting exposed epithelium
- Bandage CL is applied which is removed by Optometrist between day 3-5
12
Q
What is the implantable collamer lens (ICL) procedure?
A
- Alternative to laser eye surgery correction – usually used in pxs with higher Rxs who may not be able to undergo usual surgical correction e.g. not enough tissue thickness
- Clear implantable lenses are surgically placed either between cornea & iris or just behind iris, without removing natural lens of eye
13
Q
What is refractive lens exchange (RLE)?
A
- Natural lens replacement
- Cataract surgery
- RLE typically refers to lens replacement surgery before cataract develops –
o Huge range of Rxs covered: hyperopia/myopia up to +20 to -20DS
o Astigmatism up to -10DC
o Multifocal lenses available which are suitable for pxs with presbyopia - Lens types: monofocal distance, monovision. Or Multifocal – low & high add, extended range of vision
14
Q
What is the optom’s role on the day of refractive surgery?
A
- General health checks:
o BP check
o Further check of GH and meds - Pre-operative assessments – repeat (vision/Rx/diagnostic scans – OCT, IOL Master)
- Dilation (administer eye drops)
- Marking of eye (placing X above eye using skin marker)
- Discussions:
o What to expect
o Post-operative medications
o Signs & symptoms of complications to look for, restrictions on activities
o Eye cleaning
o Any pain management – e.g. paracetamol/co-codamol
o Details of next appt
15
Q
What is the standard advice given to pxs post refractive surgery?
A
- Rest for 24hrs
- Wear and eye shield (RLE) or goggles (LVC) whilst sleeping for 1 week
- Do not drive until advised by optom/surgeon (Day 1 post-op)
- Take pain killers if necessary (paracetamol, ibuprofen, co-codamol)
- Clean hands before handling eyedrops
- Do not rub eyes
- Post-Op Advice on Activities: (this is usually given in leaflet to px)
o Do not wear makeup for 1wk
o Avoid getting shampoo/soap in eyes
o Do not exercise intensely for minimum 1wk
o Do not swim for 2wks
o Do not play contact sports for 4wks
