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