refractive surgery Flashcards
how would you explain LASIK to a patient
this is a surgery that changes the shape of the very front surface of the eye called the cornea. the surgery uses lasers to do this and it takes a few minutes to do (5mins). Your eye is numbed and the a laser creates a flap and then another laser does the correction for your eye then the flap is closed and sealed
- then the second eye is done
how would you explain LASEK to a patient
this is a surgery where the cornea (front of the eye) is numbed and the front part of the cornea is removed and then the laser is used to treat the eye and after that is done the part that was removed is added again, then a protection contact lens is put on the eye. This surgery takes a bit longer (>10 mins)
what does LASIK stand for
Laser assisted in istu keratomileusis
what does LASEK stand for
Laser Assisted sub epithelial kerectomy
what happens at the refractive consultation -what is asked
motiviation or surgery? hobbies occupation driver, GH meds, Allergies, OH FH specs cls
cycloplegic refraction
ocular dominance
prescription hx
unaided VA
manifest refraction
cornea, conj, lids and lashes, tear quality, AC, ocular muscle balance, pupil reflexes, lens, vitrous, dilated retinal exam
pupillometry
Idesign - wavefront guided rx
pentacam - pachymetry, keratometry
OCT, IOP, VF, specular microscopy
IOL master, biometry
amount of corneal tissue needed for LASIK and LASEK
LVC – Residual Stromal bed (RSB)
LASIK > 480 microns
LASEK >450-480 microns
what is Residual Stromal bed (RSB)
Residual stromal bed (RDB) is how much tissue left after the prescription has been removed
Idesign aberometer
gives indication of what the px’s rx is and we can compare what is in their specs – to determine if there is stability there and if we can move on to surgery.
The IOL Master
is a scan that measures the dimensions of the eyeball, ( the biometry of the eye - eg AL, ACD, and also displays options for the dioptric powers of the IOL to be chosen. As is highlighted on the scan,the 23.5D will be the chosen IOL power on this scan.
What happens at a refractive consultation?
Discussions on the Refractive Procedure and outcomes
- Visual outcomes: Distance and Near. (Presbyopia -should be aware they would need SVN)
- Risks Infection / Inflammation / Poorer outcomes
- Regression – rx may come back a bit in future eg -4DS, then 2 years later -1DS
- Further surgery (LVC Enhancement (may need fine tunning with laser)/ Cataract development/ Yag laser (done if PCO posterior capsular opacification developed – happens due to RLE procedure)
Consent – Surgeon, Ophthalmologist (they have final decision)/ Patient declaration
LASIK Steps
- The cornea is anaesthetised and lid speculum inserted
- A suction ring is applied to limbus to create an immobile cornea
- The flap is created by IntraLase laser
- The flap is lifted to expose the stromal bed, the hinge most often being placed at 12 o’clock
- The eye tracker is engaged and the excimer laser is applied
- The flap is washed with balance salt solution, replaced, and the edges are smoothed down
LASEK steps
- The cornea is anaesthetised and a lid speculum inserted
- 18% Ethanol is applied to the cornea in a corneal ring for around 30 seconds to loosen the epithelium
- The edge of the loosened epithelium is lifted with a surgical instrument
- The stromal bed is exposed and the laser is applied immediately
- The epithelium is replaced (the procedure becomes PRK if the epithelium is discarded)
- A bandage contact lens is applied which is removed by the Optometrist between day 3-5
what is
Implantable collamer lens (ICL)
Clear implantable lenses are surgically placed either between the cornea and iris or just behind the iris, without removing the natural lens of the eye. An alternative to Laser Vision Correction for the treatment of patients with high ametropia or other clinical features that mean a Laser Vision Correction procedure is not possible.
Not enough corneal tissue maybe
Refractive lens exchange (RLE)
identical procedures – RLE, NLR, Cataract surgery correct ranges and lens types. Monofocal or Multifocal can be used. RLE – is when lens exchange surgery is done before cataract develops
What happens on day of surgery Optom Role
Further checks of GH and medications.
* Pre operative assessments – repeat ( Vision/RX / diagnostic scans – OCT, IOL Master)
* Dilation (administer eye drops)
* Marking of the eye
* Discussions:
On what to expect.
Post operative medications.
Signs and symptoms of complications to look for, restrictions on activities.
Eye cleaning.
Any Pain management.
Details of next appointment.
Post Operative advice
- Standard advice given to patient: Refractive patients
- Rest for 24 hours
- Wear an eye shield (RLE) or goggles (LVC) whilst sleeping for 1 week
- Do not drive until advised by an Optometrist /Surgeon(Day 1 PO)
- Take pain killers if necessary (Paracetamol, Ibuprofen, Co-Codamol)
- Clean hands before handling eyedrops.
- Do not rub the eyes.
- Do not wear make-up for 1 week.
- Avoid getting shampoo/soap in the eyes.
- Do not exercise intensely for 1 week.
- Do not to swim for 2 weeks.
- Do not play contact sports for 4 weeks
What happens at a post op appointment
- Refractive PO
Discuss: - How Vision and comfort has been since surgery.
- Eye drops regime.
- General discussions with outcomes, so far, and patient reaction.
Record: - Vision / BCVA
- IOPs
- S/lamp: lids/lashes, conjunctiva, cornea, AC, Lens, & Volk as needed
Management - Outcomes so far
- Drop regime ( Continue / when to finish)
- Any issues/concerns contact promptly
- Next review appointment.
LVC discharge medications
- After a LVC procedure it is widely accepted we should use 3 types of medications:
- Antibiotic–the incidence of Microbial Keratitis is very low at 0.0046% with LASIK (Higher incidence with LASEK and Contact Lens wearers) eg oftaquix - Levofloxacin (quinolones)
- Anti-inflammatory – required to reduce post-operative inflammation (DLK) and to help relieve dry eye symptoms.
- Lubricants – help manage the dry symptoms after eye surgery. eg blink
Predforte for LASik
FML for LASEK
RLE/ICL discharge medications
ICL discharge medications
* After a RLE/ICL procedure it is widely accepted we should use the following medications:
* Antibiotic
* Anti-inflammatory (Steroid + NSAID) – required to reduce pain and post-operative inflammation.
* Lubricants – help manage the dry symptoms after eye surgery.
RLE:
oftaquix - Levofloxacin (quinolones)
Maxidex - dexamethasone, corticosteroid
ketorolac trometamol - NSAID
ICL:
oftaquix - Levofloxacin (quinolones)
Maxidex - dexamethasone, corticosteroid
lubricating drops
Diamox tablets (Diamox (acetazolamide) is a medication used most commonly to treat glaucoma, epilepsy, and idiopathic intracranial hypertension)
refractive surgery complciations percentage
<1% serious complications
what is diffuse lamellar keratitis
- Diffuse sterile inflammation
- Occurs within 24 – 48 hours postoperatively
- LASIK Patients only
- Non specific inflammatory response
accumulation of fine white infiltrates manifests clinically as a grainy corneal opacification
The characteristic clinical presentation in DLK develops 1 to 2 days following refractive surgery and typically resolves 5-8 days after the initiation of appropriate therapy eg Steroid eye drops
treatment of DLK
- Increase steroid to hourly and review in 24-48 hours
- If it doesn’t improve then need to speak with surgeon and they may to re lift the flap
4 stages of DLK
DLK is divided into four stages according to the extent of corneal involvement.
Stage 1 typically arises 1-2 days after refractive surgery. It is characterized by peripheral inflammatory infiltrates without central corneal involvement.
Stage 2 typically arises on postoperative days 3-4 when inflammatory cells begin migrating from the periphery into the central cornea often comprising vision.
Management Stage 1 & 2 - Increase steroid to hrly & review 24-48 hrs
Stage 3 is characterized by further migrate-on of inflammatory cells and the development of permanent corneal scarring. Stage 3 is often referred to as the “threshold” because of the likelihood that eyes in this stage of DLK will develop permanent scarring and resultant loss of vision .Stage 4 describes the phase in which stromal melting and further corneal scarring occur. The significant epithelial destruction that occurs during this phase often results in a hyperopic shift. Management Stage 3 & 4 require urgent review with treating surgeon / Opthalmologist
Lasik Flap Complications
striae
dislodged flap
management of disloged flap
seek urgent surgeon review
what are striae
fold in the flap
If the folds are large enough or lie on your visual axis, they can affect your vision. The top picture in this slide demonstrates Micro striae - faint wrinkles
symptoms of striae
Reduced Vison & poorer QoV eg glare / haloes The Surgeon can correct these folds by lifting, stretching, and repositioning the flap again if they are detected at an early PO appointment. Reduced BCVA.
what is a dislodged flap
The causes of a dislodge flap are mainly: Eye rubbing or squeezing, A Poor Epithelial, Excessive dry eyes or a bump to the eyes. This is painful and will require immediate surgeon review to reposition the flap. Visually significant. This flap has moved nasally
epithelial growth symptoms
- Often asymptomatic but discomfort / Light Sensitivity
- If progressive, induced Astigmatism (cyl)
- This is the development of epithelial tissue underneath the corneal flap. Appearance is sometimes referred to as a Visible nests of cells. An Epithelial ingrowth can cause some discomfort, sensitivity to light, and/or can affect vision. The surgeon can correct epithelial ingrowth by lifting the flap and removing the ingrown tissue.
Slow Epithelial healing, symptoms and management
Vision can be affected, Discomfort, Lacrimation, and usually need a further BCL toa be inserted to aid comfort. Antibiotic eye drop may also may prescribed
when is corneal haze more likely to occur, management
Corneal haze is more likely after LASEK, because the laser energy is applied directly to the surface of the cornea. Onset usually between 1 – 3 months post-operatively. Corneal haze will resolve naturally as healing completes. In more severe cases a doctor may prescribe eye drops eg Steroid eye drop to encourage healing, allowing the haze to resolve quicker.
dry eye aetiology
Suction effects on goblet cells / mucin layer
* Alteration in corneal curvature with alteration in
* Surface wetting
* Corneal denervation with flap creation
* All LVC patients experience transient dry eye symptoms, normally for around 1-3months.
* The aetiology is related to the change in the shape of the cornea and the denervation of the nerves especially when creating the cornea flap in LASIK. Typically, all LVC patients will experience dry eye symptoms for approx. 1-3 months post surgery, but in other cases it can require ongoing treatment. The Optometrist and surgeon should screen for dry eye at the preoperative consultation, and treat prior to the procedure with Artifical tear eyedrops / lubricates to reduce risk of dry eye post surgery
what is corneal ectasia
is the thinning of the cornea. Post-LASIK ectasia is a rare complication and usually occurs month- to years after the initial surgery.
symptoms of corneal ectasia
The symptoms of corneal ectasia can vary for each person. Common cornea ectasia symptoms include: Astigmatism or blurred vision at all distances Changes in the shape of the cornea. Seeing glare, halos, and starbursts around lights - reduced quality of vision
timescale of corneal ectasia
months - years post op
location for corneal ectasia
often inferiorly
appearance for corneal ectasia
often normal cornea, in advanced cone shape cornea
management of corneal ectasia
- Early intervention is critical / Urgent surgeon referral
- If increase in cyl and/or decrease in BCVA, capture pentacam
- Cross-linking
Corneal cross-linking is a surgical procedure, which strengthens the collagen bonds of the cornea, this slows down the thinning of the cornea in ectasia.
RLE complications/ NLR/ Cataract surgrey
- Infection occurs in less than
Approx. 1 in 1,000 people (0.1%) - Inflammation - Endophthalmitis
- A rare but severe sight-threatening complication of surgery.
URGENT Surgeon review or HES emergency referral
cystoid macular oedema
It usually occurs two to eight weeks after surgery.
Reduced Vision.
First-line treatment of postsurgical CMO can include
Topical eye drops: Pred Forte, Acular and Acetazolamide
A Condition where fluid accumulates in the centre of the retina, causing blurred vision.
CMO - A common cause of poorer vision after both RLE and cataract surgery.
CMO Usually develops 2-8 weeks after surgery
Preexisting conditions such as diabetes mellitus and uveitis as well as intraoperative complications can raise the risk of postsurgical CMO. Most cases of CMO, post refractive lens exchange will resolve spontaneously. However, topical eye drops can be considered to manage
RLE complications
- Increased IOPs ( Steroid responder)
- Retinal Detachment
- IOL displacement
- Posterior capsular Opacification ( Yag laser needed )
what is a YAG laser and when is it used
YAG laser – polishes the back surface of the lens
in cataract surgery the IOL is held in place in the eye’s natural lens capsule. Weeks, months or years later, this capsule can become cloudy or wrinkled, causing blurry vision. This is called a posterior capsule opacification (PCO). It’s also sometimes called a “secondary cataract” or “scar tissue.” With posterior capsulotomy, a laser is used to make an opening in the cloudy capsule. This allows light to pass through again for clear vision
what happens during a YAG laser
The procedure is done in your ophthalmologist’s office or an outpatient surgery center. It only takes about 5 minutes. Here is what will happen:
Your eye will be numbed with eye drops. You may be given other eye drops as well to dilate your pupil.
Your ophthalmologist will point a special laser at the back of the lens capsule and make a small opening.
Once your vision is clear after the procedure, you can usually do all of your normal daily activities. But you may need to have someone drive you home.
You may need to use eye-drop medicine for a few days after the surgery. Your ophthalmologist will let you know if this is necessary.
If you have no other eye problems affecting your vision, your sight should improve in about 24 hours.
risks of YAG
retinal detachment
The pressure in your eye may increase.
The IOL might move through the posterior capsule opening.
You may have swelling in your eye, and you may need steroid eye drops.
post op check timings for RLE and ICL
day 1 in clinic
1 week telemedicine
1 month in clinic
3 month telemedicine
post op check timing for LASIK
day 1 in clinic
1 month in clinic
3 month telemedicine
post op check timings for LASEK
day 1 telemedicine
3-5 days in clinic for bandaage cls removal
1 month in clinic
3 month telemedicine
