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 AstimatismPre-existing Astimatism Incision induced AstimatismIncision induced Astimatism Suture induced AstimatismSuture induced Astimatism Wound burnWound 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 meridianAny loose suture (wound gap) flattens it ’ s own meridian

Any none radial suture, induces irregular Ast. (None predictable)Any none radial suture, induces irregular Ast. (None predictable)

Vertical mismatch, induces predictable astigmatism: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: PreoperativePreoperative InteraoperativeInteraoperative Post operativePost operative

Preoperative: PHACO, Except for difficult or impossible cases.PHACO, Except for difficult or impossible cases.

Interaoperative: Incision (main incision & relaxing incision)Incision (main incision & relaxing incision) SutureSuture Avoiding wound burnAvoiding wound burn

Main incision Both phaco & ECCE More posterior incision Ast.More posterior incision Ast. Smaller incision Ast.Smaller incision Ast. Three-plane incision Ast.Three-plane incision Ast.

Site of incision: Temporal approach incision, induces less Ast., because it ’ s farthest from the visual axis.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.Although small incision of phaco, induces minimal cylinder, it is better to make incision on the steep meridian.

Relaxing incision (Astigmatic Keratotomy, AK)Relaxing incision (Astigmatic Keratotomy, AK) If, pre-existing cylinder is more than 1.75D, relaxing incision on steep meridian is necessary for Ast. correction. 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 ).Relaxing incision, also can be made on limbus, which is more effective ( LRI ).

Suturing:Suturing: -Horizontal -Vertical -Rotational Misalignment, induces Ast., and so, have to be avoided.

Post operative: Selective suture removedSelective suture removed GlassesGlasses Relaxing incision (AK)Relaxing incision (AK) Laser (PRK, LASIK)Laser (PRK, LASIK)

Glasses: ECCE: 1m after suture removedECCE: 1m after suture removed Phaco: 2w after surgeryPhaco: 2w after surgery

AK & Laser For ECCE >6mFor ECCE >6m For phaco >6wFor phaco >6w