management of post cataract surgery astigmatism
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
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- RotationalMisalignment, 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