8.2 Refractive surgery complication Flashcards
Preoperative evaluation
Cycloplegic refraction & BCVA
Corneal topography and pachymetry
Pupil diameter
Tonometry
Binocular vision
Ocular health assessment
Dry eye evaluation
Pre-operative considerations
Age (>18 18-21 years old)
Stability of Rx
Systemic disease (e.g. DM, autoimmune disease)
Pregnant or nursing
Ocular disease:
* Lid disease
* Glaucoma
* Cataract
* Dry eye
* Corneal degeneration
* Herpes simplex keratitis
postoperative medications
Topical Steroid (Prednisolone qid taper to tid and then
bid each for a week)
Topical antibiotics (Fluoroquinolone qid for a week)
Artificial tear
Topical NSAID and oral analgesic may be added for pain in surface ablation procedures
Postoperative precaution
No eye rubbing
Sleep with protective shields
No swimming for one week
No vigorous exercise for one week
No eye makeup for one week
RK complication
Unstable refractive error
Starbursts/ glare
Epithelial plugs
Vascularization of stromal scars
Infectious keratitis
Perforation of the cornea
Refractive Surgery Associated Dry Eye
Proposed mechanism
Corneal nerve changes
Inflammation
Mechanical
Conjunctival
Untreated Preoperative DE
Symptoms: FB sensation, mild to
moderate discomfort, tearing,
photophobia, decreased vision
Begins 1 day post post-operative
what is the condition, and Mx
Diffuse Lamellar Keratitis
Sterile interface inflammation
Stages:
1: Peripheral faint WBC
2: Central scattered WBC
3: Central dense, clumped, WBC
4: Permanent scarring or stromal melting. Cracked appearance.
Mx:
Stage 1-2:
Topical Steroid Pred q1h
consider steroid ointment qhs
Daily FU to monitor progression
Stage 3-4:
Lift flap irrigation of the bed and interface of the flap
Topical or oral steroids
DLK vs MK
DLK
Usually starts within 24 hrs
Starts at flap periphery
Mild redness and pain
No anterior chamber rxn
Diffuse inflammation
confined to interface
MK
Early or late onset
Occurs anywhere under flap
Moderate to severe redness and pain
+ anterior chamber rxn
Focal inflammation around infection that extends anterior and posterior
Epithelial ingrowth
Mx
Not affecting vision
>monitor
Visual axis
>lift the flap and scrape the epithelial cells from the stromal bed and the undersurface of the flap
Optical aberrations
e.g. glare, halo,
Symptoms worse at night
Mx:
Off label: Brimonidine 0.2% or 0.15%
Possibly Vuity (pilocarpine)
but may cause headache/ accommodative spasm (especially in younger px)
Severe photophobia
Presents 2-8 weeks after surgery
VA and slit lamp findings normal
what is this condition and management:
Transient light sensitivity syndrome (TLSS)
Due to keratocyte activation caused by the femtosecond laser
Management: topical steroid qid for 2-3 weeks
main causes of over/under-correction
Data entry error
Inaccurate refraction
Laser calibration issues
Corneal hydration
Abnormal wound healing response
main causes of regression
Postoperative corneal changes
Nuclear sclerosis
Axial elongation
IOP considerations
Intraoperative
LASIK patients experience an IOP spike ( 60 to >100
mmHg ) during the application of suction ring and
creation of the flap.
Early postoperative
Risk of corticosteroid-induced increased IOP
Pressure induced interlamellar stromal keratitis (PISK)
Long term postoperative
Artificial reduction of measured IOP
Subepithelial corneal haze
Appears several weeks after ablation
Worst at 1 to 2 months
Disappears in 6 to 12 months
after what surgery
Mechanism
Mx
Corneal Haze
Increased keratocyte activity cause deposits
Treat with steroids or topical MMC
