unit 3 Flashcards
Corneal Inlays
-INTACTS
-KARMA
Types of refractive surgery
-LASIK
-PRK
-RK
-LRI
-CRI
Corneal procedures
-PK
-CXL
Lens based correction
-RLE
-IOLS (standard, toric, presbyopic, phakic, piggyback)
4 surgical alternatives to eyelgasses
-refractive sx
-corneal procedures
-corneal inlays
-lens based correction
4 non surgical alternatives to eyeglasses
-contact lenses
-low vision aids
-occlusion therapy
-pharmacological
occlusion therapy
-patching
-atropine penalization
low vision aids
-hand held magnifiers
-telescopes
-tech based magnifiers
-pharmacological
-botox for strabismus
-low dose atropine for myopia control
basic types of corneal refractive surgery
- laser based surgeries
- blade-based surgeries
- corneal inlay
- other corneal procedures
laser based sx
-use a laser to adjust the corneal shape by removing tissue or creating incisions
(photoablate or photodisrupt the corneal tissue)
-can be preformed for all types of refractive errors
how LASIK works
-local anesthetic is used
-treatment is done by sculpting the corneal stroma
-a thin anterior corneal flap is created with a femtosecond laser or mechanical keratome (blade)
-the flap (epithelium and bowmans) remains attached by a hinge of tissue and is lifted to expose the stroma layer
-the intrastromal tissue is respahed using the excimer laser
what is LASIK done for
treat myopia, hyperopia and astigmatism (+4.00 to -12.00)
cyl - -0.5 to -4.00
how long does it take for the acuity and comfort to be better after LASIK
first few days after sx
SBK (Sub-bowmans keratectomy)
-similar to LASIK
-a femtosecond laser creates a VERY THIN anterior corneal flao. (blade less lasik)
-desired power treatment is applied to the exposed corneal bed
-sometimes know as “FS-assisted) LASIK
complications with LASIK
-dry eyes
-glare/halos
-double vision
-over or under-correction or regression
-vision loss or change
-quality of vision decrease
-corneal neuralgia
-epithelilal ingrowth
-diffuse lamellar keratits
flap complications with LASIK
-microstriae
-debris
-taco flap
-incomplete flap
-buttonhole
-flap displacement
-decentered flap
-free cap
corneal neuralgia
-neuropathic corneal pain / damage to corneal nerves
-causes your eyes, face or head to be “over sensitive”
-doctors dont know the exact cause of the neuropathic corneal pain
-pxs are typically referred to a pain management clinic
-condition where corneal pain is seen in response to normally non-painful stimuli
DLK
diffuse lamellar keratitis
-non infectious inflammatory infiltrates
-treated with a steroid drop such as predforte or maxidex
PRK (photorefractive keratectomy)
-Similar to LASIK, but no corneal flap
-epithelium is removed and excrimer laser treatment is done on the anterior stromal surface
people who do combat / competitive sports , is it recommended to get LASIK or PRK
PRK - for the reason being that their is no flap
does PRK or LASIK take longer to recover?
PRK
how long till your VA gets better with PRK
5 to 7 days
what does PRK treat
myopia and astigmatism
-can treat hyperopia but not ideal as its less predictable
who is PRK typically done on?
-pxs with thin corneas
-abnormal corneal topographies (not kerataconus)
-px into combat competitive sports
how to remove the tissue in PRK
-excimer laser
-alchohal and saline then scrapped off
what is used after reshaping the cornea (PRK)
mitomycin-C
which helps prevent scaring/haze
-then a bandage contact lens is inserted for approx 5-7 days
complications with PRK
-delayed visual recovery
-over or under correction
-decentered treatment
-haze or scaring
-dry eyes
-corneal ectasia
-infection
-corneal neuralgia
blade based surgeries
-a blade is used to ‘relax” the cornea
-now mostly used to correct astigmatism
radial keratotomy (RK)
was a blade based method used for spherical and astigmatic errors
-results did not provide refractive stability
-largely abandoned
SMILE: small incision lenticule extraction
-laser-based correction of refractive error
-considered minimally invasive
-involves a small incision and the creation of a lenticule (disc shaped piece of cornea)
Corneal Inlay procedures
-artificial material is involved
-tissue is not removed
-may have greater reversibility
-plastic device is placed between the layers of the cornea to flatten or steepen it.
-may be used for small amounts of myopia and astigmatism, to bolster a weak cornea or for correction of presbyopia
what is lenticule
disc shaped piece of cornea
INTACTS corneal inlay
-optically clear, arc-shaped devices
-two separate effects:
-to flatten the corneal surface in cases of mild myopia associated with keratoconous
-to flatten certain meridians to help correct astigmatism associated with keratoconus
KARMA corneal inlay
-small opaque device implanted centrally
-allows only central light through
-increases depth of foucs (like a pinhole), with the intent to eliminate the need for reading gls
-FDA restricts KARMA to one eye in pxs who have not had cataract sx
Penetrating keratoplasty
Corneal transplant - full thickness replacement from a donor cornea
Corneal cross-linking (CXL)
-a special concentration of sterile riboflavin (Vitamin B2) eye droped are applied at specific interals before stictly timed UV exposure
-Strengthens the chemical bonds within the cornea to halt progressive and irregular changes in corneal shape due to conditions like keratoconus
-refractive changes are mostly minor
pre-op evaluation
-a full EE is recommneded prior to referring the px
-ocular and health history
-refractive status
-dilated ocular health exam
this allows surgical team to pre screen and discuss any issues
-px is required to discontiune soft CL wear for a min of 48 hours prior to testing and 2 weeks for RGPS
Contraindications for corneal refractive sx
-ocular pathology
-corneal scar/disease
-extreme dry eyes
-systemic pathology (autoimmune disorders, rheumatoid arthritits, lupus)
-medications (accutane)
post op evaluation
-after the 1 day follow up visit, the px is encouraged to return to the co-managing optometrist for their f/u care
-f/u frequency and testing differs for each type of procedure
-post op follow up referral form should be sent to the surgical centre for review
-ensure we are monitoring infection and inflammatory response
LASIK post op care/medications
-steroid
-antibiotic
-AT - q15-30mins x 2day
-eyesheilds 5-7 nightsf
follow up schedule for LASIK
day 1
week 1
month 1
yearly
PRK post op care/medication
-steroid
-antibiotic
-pain relief
-AT - q15-30 mins until bandage CL removed
-eye shield 5-7 nightsf
follow up schedule for PRK
day 1
day 3
week 1
month 1
yearly
POST OP PRESENTATION FOR LASIK
-VA 20/15 to 20/50 (may take 3-5 days to start improving)
-Foreign Body Sensation (48 H)
-Tearing/Photophobia (72 H)
-Dry Eyes (up to 6M)
-Sub-conjunctival hemorrhage (2-3W)
-Ghosting/Halos/Glare (2-3M)
POST OP PRESENTATION FOR PRK
-VA 20/30 to 20/400 (up to 1W)
-Mild to severe pain (48H)
-Foreign body sensation (3-5D)
-Tearing, Photophobia (3-5D)
-Lid edema (3-5D)
-Ghosting (2-4W)
-Dry eyes (up to 3M)
-Halo/Glare (2-3M)
-Drop in VA/diplopia (occurs at day 3-5)
What NOT to do after sx
-No pets in the bed
-No eye make-up
-No swimming, hot tub, water sports
-No dusty/smoky environments
-No eye rubbing
-UV protection
-Safety glasses during appropriate activities
Non-surgical alternatives to eyewear
-orthokeratology
-presbyopia eye drops
-patching
-atropine therapy
Presbyopic drops 2 methods
-Miotics
-Lens softening
Miotics (presbyopic drops)
-Change the size of the pupil (Creates pinhole effect)
-Pilocarpine drop
-Daily rx eye drop that works in as little as 15 mins and lasts 6 hours
-most common adverse effects were headaches and eye redness
Lens softening
-Softens the eyes aging lens
(lens regains flexibility, the eye can better focus up close)
-Cannot completely restore near vision
-May work best for ppl w/o cataracts who are in the early stages of presbyopia
what age is treatment for amblyopia most successful?>
before the age of 7
-early detection is crucial
Treatment success for amblyopia depends on..
-the age of onset
-cause
-severity
-duration of amblyopia
-type of treatment
-adherence to therapy
2 methods of treating amblyopia
-surgery
-patching
-penalization
surgery for amblyopia
strabismus sx is performed to align the eyes
-involves loosening or tightening the muscles
-goal is to include reduction/ellimination of diplopia, improvement of stereopsis and cosmesis
-amblyopia is treated first so both eyes have the best VA before surgery
patching for amblyopia
-occlusion involves covering the stronger eye
-continued until the VA becomes equal in each eye or until there is no improvement after 3 to 6 months
types of patches available
-sticky patches
-cloth patches that fit over gls
Penalization
involves blurring the good eye through cycloplegic eye drops (atropine 1%)
-decrease accommodation and the ability to focus
Manahement of strabismus
-spectacle correction
-prism
-botox
-surgery
Spectacle correction for strabismus
-cycloplegic refraction
-prescription - mainly based on objective findings until around age6
-bifocal - allows for sufficient relaxation of accomodation to allow for near fusion
-sometimes prism is needed to help control diplopia (try w fresnel then u can prescribe it)
Fully accomodative esotropia may correct with a full time plus or minus rx?
PLUS
Botulinum Toxin
Injection of botulinum toxin type A into an EOM produces dose dependent paralysis
-several days after the injection the chemical paralysis of the muscle allows the eye to be moved into the field of action
-chemically paralyzed muscles it stretched / lengthend
Surgery for strabismus
-goal is to improve ocular alignment and help the eyes achieve binocular single vision
-muscle weakening / strengthening
-the muscle is detached from the eye and resewn to the eye at a measured distance
-the muscle is detached, shortneed and then resewn
-not performed on small deviations (<10D)
