Refractive Sx pre-op Flashcards
Why do we look for refractive stability +/-0.50?
Look for undiagnosed keratoconus
Patient satisfaction
Is diabetes a contraindication to Rx surgery?
No.
How long must you leave RGPs out for prior to surgery?
at least 3 weeks or a week for every decade they have worn them
How long must soft lenses be out for?
at least 1 week
Is pupil size still important?
With femto-second flaps and larger ablations probably not.
What mesopic size pupil should be treated cautiously?
7mm
Total RMS of 0.4 with a 6mm pupil could indicate what?
undiagnosed keratoconus
crystalline lens changes
What sorts of pachymetry are there?
Ultrasound
Anterior segment OCT
Schiempflug imaging
Scanning slit on orbscan
What LASIK corneal stromal bed should you aim for?
250 microns
What post-lasek corneal thickness should you aim for?
350 microns
Which causes less dry eye, femto-second or manual keratome or LASEK
LASEK (least)
Femto (more superficial cut)
Microkeratome (worst)
What steepness of cornea should you avoid to prevent dry eye?
Shouldn’t be steeper than 48/9D
Azar looked at schirmer without anaesthesia pre-op - what did he find?
If pre-op greater than 20mm then normal tear film (TBUT> 10secs) at 9 months
If pre-op greater than 10mm then no significant dry eye symptoms albeit some