Corneal Surgeries and CL considerations Flashcards
Hydrops are a break in which layer(s)?
Descemet’s membrane and underlying endothelium
aqueous humor leaks into the stroma leading to edema
What are symptoms of hydrops?
sudden onset decreased vision, irritation/ pain; photophobia
What are the signs of hydrops?
observable break in Descemet’s membrane, anterior and posterior stromal edema with possible epithelial involvement, and hyperemia of the conjunctiva
patients may notice a white spot on their eye
Hydrops can be found with which disorders?
Keratoconus, PMD; post-lasik, post RK or post-PKP ectasias
How long does it take for hydrops to resolve?
3-6 months
monitor monthly dt potential for neovascular hydrops
When no epithelial compromise, can treat conservatively….
What is the supportive therapy for Hydrops?
artificial tears PRN
topical NSAID or steroid TID-QID for pain and inflammation
Gas/ Air may be injected intracamerally to treat hydrops; what does this prevent?
air, perfluoropropane (C3F8) or hexafluoride (SF6)
aqueous humor from entering descemet’s and the stroma
faster healing of corneal endothelial cells
Why might hydrops be considered a blessing in disguise?
There may be a flattening effect with scar formation
easier to fit corneas that were initially too steep
What are the contact lens options for hydrops?
Corneal GP; Piggyback system; specialty soft lenses; hybrids; sclerals
GP: larger diameter; RoseK or reverse geometry; SCL: rigid modulus/ thicker
What is crosslinking used for?
Strengthening collagen fibers in the cornea; prevent further progression of KC
Is epi-on or epi-off the FDA approved technique for CXL?
Epi-off
What is a benefit of epi-off CXL?
Riboflavin saturates the cornea faster and deeper than with epi on
What are the benefits of epi-on CXL?
less invasive; less painful; faster recovery
What are the adverse affects of CXL?
punctate keratitis, corneal striae, corneal epithelium defect, eye pain, reduced visual acuity; corneal opacity/ haze
reduced VA: up to 6 months to resolve
Corneal haze: up to 12 months to resolve; or permanent
What signs of KC progression can qualify a patient for CXL?
- increase in steepest K by >/= 1.00D
- Increase in regular astigmatism during refraction >/= 1.00 D
- myopic shift during refraction (SE, >/= 0.50 D)
- Steepening of BCR of corneal GP >/=0.10 mm
Must have at least one
How many cross-linking procedures will a patient need?
typically just one
follow up every 6 month to monitor for progression
How long should patients stay out of CL’s before CXL?
1-2 weeks before consultation visit; 3 days before procedure
When are contacts re-fit after CXL?
1 month follow up
What material are Intacs made of?
PMMA
What is the name of the alternative to Intacs made from corneal donor tissue?
CAIRS
What is CXL Plus?
Cross linking combined with refractive procedure (PRK, ring segments, phakic IOL implant, refractive lens surgery)
What is the oral alternative to CXL that is being studied?
Mega-dose riboflavin and sunlight (without eye protection from the sunlight)
sun exposure for 15 min/ day at peak UV index
Which surgical procedures are used for the anterior layers of the cornea?
SK and PTK
PTK removes deeper layers of tissue
What conditions can SK/ PTK be used to treat?
EBMD, Recurrent corneal erosions, Salzmann’s nodular degeneration, calcific band keratopathy, superficial corneal scar
Penetrating keratoplasty replaces which layers of the cornea?
All of them
What is a complication of PK/PKP?
secondary, high, irregular astigmatism (and subsequent anisometropia)
slow recovery
CL refit at 12 months post-op or earlier if stable
Which layer(s) does DALK replace with donor tissue?
Stroma
endo and descemet’s are retained
What are the indications for DALK?
KC, stromal scars, dystrophies
diseases not involving the endothelium
Which layers are replaced during DSAEK?
Descemet’s membrane and endothelium
donor tissue includes thin layer of posterior stroma
Which procedure uses an air bubble to attach donor tissue to the the recipient stroma without sutures?
donor tissue: DM, endothelium and thin layer of posterior stroma
DSAEK
Descemet’s Stripping Automated Endothelial Keratoplasty
Which device uses a host-tissue friendly outer skirt with a high affinity for recipient rim tissue with a host-tissue unfriendly central clear optical region that has a low affinity for host tissue?
Boston Keratoprosthesis
Usually done with removal of crystalline lens
What common test can not be done with the Boston Keratoprosthesis?
tonometry
What topical meds will a patient need for life after K-Pro?
topical antibiotic, topical steroid, topical glaucoma med
