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Management of post cataract surgery
Astigmatism
H.R.Ziai MD
Since phaco became routine procedure, Ast. is not an important problem, however, it needs to disccused about.
Sources of post op. Astimatism
• Pre-existing Astimatism
• Incision induced Astimatism
• Suture induced Astimatism
• Wound burn
Incision induced Astimatism
Any incision, relaxates meridian which is vertical to the incision
Suture induced Ast.
Any tight suture,
steepens it’s own
meridian
• Any loose suture (wound
gap) flattens it’s own
meridian
• Any none radial suture,
induces irregular Ast.
(None predictable)
• Vertical mismatch, induces predictable astigmatism:
- Deep corneal to superficial scleral bite, flattens corneal curvature
- Superficial corneal to deep scleral bite, steepens corneal curvature
Wound burn:
It induces irregular wound
& irregular Ast. , that
often can not be
compensated.
How to manage it?
Management:
• Preoperative
• Interaoperative
• Post operative
Preoperative:
• PHACO, Except for
difficult or impossible
cases.
Interaoperative:
• Incision (main incision &
relaxing incision)
• Suture
• Avoiding wound burn
Main incisionBoth phaco & ECCE• More posterior incision Ast.• Smaller incision Ast.• Three-plane incision Ast.
Site of incision:• Temporal approach incision,
induces less Ast. , because it’s farthest from the visual axis.
• Although small incision of phaco, induces minimal cylinder, it is better to make incision on the steep meridian.
• Relaxing incision (Astigmatic Keratotomy, AK)
• If, pre-existing cylinder is more than 1.75D, relaxing incision on steep meridian is necessary for Ast. correction.
• Relaxing incision, also
can be made on limbus,
which is more effective
( LRI ).
• Suturing:
- Horizontal
- Vertical
- Rotational
Misalignment, induces Ast. , and so, have to be avoided.
Post operative:
• Selective suture removed• Glasses• Relaxing incision (AK)• Laser (PRK, LASIK)
Glasses:
• ECCE: 1m after suture removed
• Phaco: 2w after surgery
AK & Laser
• For ECCE >6m
• For phaco >6w