9. Glasses
• Easy and difficult!
• Cause distortion of images and depth due to dissimilar meridional
magnification in eyes
10. Easy cases
• Persons that have had astigmatic glasses for years or from childhood
• Minor vertical or horizontal astigmats
• Monocular patients, and children
11. Most difficult ones
• New glasses with > 2.5 diopters of oblique astigmatism and
enantiomorphism
• Impaired proprioception (diabetics in some stages)
12. Contact lens
• Always worth try in difficult cases
• Irreplaceable for irregular astigmatism
13. Incisional methods
• AK
• Arcuate
• Straight
• LRI
• Induced wound dehiscence
• After PKP or improperly sutured wounds
• Compression sutures & wedge resection
• Paired full 3.2 incision
• FS assisted
14. • Incisional methods mostly used during or after a major intra-ocular
surgery like cataract extraction or PKP
16. Excimer ablation
• Case selection
• R/O lens problems
• Lens tilt or subluxation
• Lenticonus
• R/O KC
17. Evaluations
• Inquiry about recent refractive change and FHx of KC
are important
• Check both Placido based topographies and
elevations
• In Pentacam check
• 4 map
• Front & Back elevations in detail
• Belin enhaced ectasia map
• Refractive map for KC indices
23. • Use front and back Pentacam elevation maps with “toric ellipsoid fixed” reference if you have
decided to proceed to surgery.
24. Measurements
• Always look at autorefraction
• Check subjective refraction and BCVA
• Consider keratometric astigmatism
• Amount
• Axis
• Check PPR and optical aberrations
25. • Decide for the amount and axis of the correction seeing all
measurements
• Under-correct the power for at least 5% to decrease induced
astigmatism due to angle of error of corrections.
• Check, check, and recheck the numbers at each stage.
27. WF guided ablation
(APT)
• Best for moderately aberrated corneas
• Not suitable for highly aberrated eyes
• Removes much higher amount of tissue
• Post-op hyperopia may arise
• Not appropriate for patients with non-corneal
aberrations
• Crystalline lens opacities
• Cloudiness of vitreous
• No benefit in eyes with low aberration
28. Errors of angle of correction
• Exact alignment of measured angle of astigmatism with angle of
correction is of paramount importance for best results in astigmatic
correction.
29. Basis of error in angle alignment
• Position of head and eyes are different in upright measurement phase
and supine correction stage.
• Incorrect position of head compared to body in operation cradle.
• Misaligned and unlucked operating bed.
36. • This type of rotation does not occur in supine position.
• This phenomenon cause error even if the amount of tilt were similar in
upright and supine positions
37. Rotational registration
• Manual
• Mark 90, 180, and 270 in upright
• Re-align with axes in operating bed
• Automated
• Iris image registration
38. Automated Iris registration
• Takes iris image in sitting position
• Takes another image immediately before Sx and compensate rotation
comparing two images
39. Iris registration tips
• Add another image taken in exam room with room lights on
• Turn off lights in OR
• Align with pupil center exactly
• Don’t move head until beginning of ablation
40. Tips (cont.)
• If registration unsuccessful:
• Turn off all lights even of monitor and red green target lights
• Use both of two LED IR light sources
• I prefer to remove epithelium before registration for quick continuing
of the surgery.
41. Toric pIOLs & IOLs
• Available options:
• Toric phakic artisan
• Toric Artiflex
• Toric ICL
• Toric IOLs of multiple brands
• Toric supplement IOLs for sulcus
