Fitting Irregular cornea Flashcards
(15 cards)
Requirements of cl
Preserve integrity of corneal epithelium
Sufficient o2 to susceptible cornea
Protrusion graft
Donor too large for recipient
Proud graft
Host cornea too thin @junction - shelf
Sunken graft
Donor same size graft - easy fit
Tilted graft
Variations in margin thickness/suture depth
Can -> decentred cl
Eccentric graft
Centred on thin /scarred corneal area
Increases complications
Post PK cl fit
GP cls:
- large TD (9.5-12mm)
- central vaulting
- fenestrations if needed
Reverse geometry - SCLs Sutures still in place Customised toric design Piggyback fit - low power - high dk/t
Post graft fit
Graft may b tilted
BOZD»graft - avoid abrading scarred areasa
Flex lens
Piggy back lens
1mm flatter than flattest k
1-1.5 limbal draping
GP cl diam 1mm smaller than anterior cut out boundaries - facilitate cl movement/tear exchange
Keratonic fitting principles
Apical bearing - increases apical scarring
3 point touch
Apical clearance - best choice
KC fit considerations
Cone size /position/shape
Corneal toricity
Corneal e value
PMD
2 cones
SCLERAL best option
Collagen cross linking process
Topical riboflavin drops 30mins
UV 30mins
Bandage cl 5 days after
No cl wear 3-4months post op - allow keratocyte regeneration
CXL
Decrease keratocytes in anterior stroma - repopulates over next 3-9months
Expect 1-2D diff in ks
Attempt to age cornea not cure - vision may decrease
Contraindications for CXL
Stromal thickness <400u
Corneal scarring
H/o kernes keratitis
