Comlication of IOL implantation

Comlication of IOL implantation

Dr A.AshtariIsfahan university of medical sciences

2Decentration and DislocationDecentration may occure in following situationAsymetric haptic placement,with one haptic in the bag and the other in the sulcusInsufficient zonular or capsular supportThe presence of irregular fibrosis of the post capsulCapsular phimosis

3Decentration can produce unwanted glare and reflection if the edge of lens is within the pupillary space

4If zonular support is inadequate the surgeon should attempt to rotate the IOL to a position where clinical evidence shows sufficient capsule and zonular fibers to support the implantThe use of transcorneal iris fixation sutures(Mc-Cannel sutures)to secure the IOL may also be considered

5Irregular posterior capsul fibrosis gradually decenters the IOL.Deformation of the haptics may render simple rotation insufficient to center the IOL properlyIt may become necessary in these cases to move the IOL haptics into the ciliary sulcus or replace the capsul fixated IOL with a posterior chamber sulcus-fixated IOL.

6If dislocation of the IOL is complete the surgeon can sublux the optic of the implant into the pupil by means of vitrectomy technique and use transcorneal iris-fixation sutures to fix the 2 haptics of the implantAltenatively,the implant may be removed altogether and replaced with either an anterior chamber IOL or a transscleral or iris-sutured posterior chamber IOL.

7Subluxatio of scleral-fixated sutured IOL has been reported 3-9 years after implantation with 10-0 polypropylene fixation sutures.Double-fixation techniques and thicker 9-0 polypropylene sutures are currently recommended for scleral fixation of IOLs.

8Pupillary captureCauses:Formation of synechiae between the iris and underlying posterior capsuleImproper placement of the IOL hapticsShallowing of the anterior chamberAnterior displacement of the posterior chamber IOL optic

9Ant displacement of post chamber IOL optic is associated with:Placement of non angulated IOL in ciliary sulcusUpside-down placement of an angulated IOL so that the IOL angles anteriorlyPositive vitreous pressure

10Placement of a posteriorly angulated post chamber IOL in the capsular bag decrease the likelihood of pupillary capture

11Usually,pupillary capture is a purely cosmetic issue;the patient is otherwiseasymptomatic and can be left untreared Occasionally pupillary capture can cause problem such as:GlarePhotophobiaChronic uveitisUnintended myopiaMonocular diplopia

12Mydriatic can sometimes be used succesfully to free the iris through pharmacologic manipulation of the pupilIf conservative management fails,surgical intervention may be required to free the iris,break the synechiae,or reposition the lens

13Capsular block syndromCapsular block syndrome is an uncommon postoperative complication of capsular bag-fixated posterior chamber IOLAqueous becomes trapped within the capsular bag,between the post capsul and the post surface of the IOLThere is forward displacement of the lens optic with a resultant myopic shiftThe fluid behind the IOL may have a turbid or milky appearance

14Nd:YAG laser post capsulotomy results in release of the fluid,post movement of the IOL optic to its original position,and resolution of the myopic shift

15Uveitis-glaucoma-hyphema syndromFirst described in the context of rigid ant chamber and closed-loop IOLsThe classic triad or individual elements may occure as a result of inappropriate IOL sizing,contact between the implant and vascular structure or the corneal endotheliumor defect in implant manufacturing

16UGH can also occure in pt with post chamber IOL owing to contact between the lens loops and uveal tissuein the post chamberUGH may respond to treatment with topical anti inflamatory medication or anti glaucoma medicationIf the symptoms are not alleviated sufficiently by mediacl therapy or inflammation threatens either retinal or corneal function,IOL removal must be considered

17This procedure may be very complicated because of inflammatory scars,particulary in the angle If such scarring is present,the surgeon may need to amputate the haptics from the optic and remove the lens piecemeal,rotating the haptics material out of the synechial tunnels to minimize trauma to the eye.In some cases it is safer to leave portions of the haptics in placesEarly lens explantation may reduce the risk of corneal decompensationand CME

18Pseudophakic bullous keratopathyCertain IOL design,particularly iris-clip lenses(iris-fixated lenseswith the optic anterior to the iris)and closed-loop flexible anterior chamber lenses,are associated with increased risk of corneal decompensation Iris clip lenses have been shown to contact the corneal endothelium during eye movementChronic endothelial cell loss associated with closed-loop IOL is thought to be due to chronic inflammation and contact between the lens and peripheral corneal endothelial cellsBoth types of lenses are no longer in clinical use

19Patinets with underlying corneal dysfunction such as Fuchs dystrophy are at greater risk fer developing postoperative corneal edema.Progressive stromal edema eventually leads to bullous keratopathy

20Iol Design,Glare,and OpacificationIn addition to lens decentration and capsular opacification,glare can result when the diameter of the IOL optic is smaller than the diameter of the scotopic pupilOptics with a square-edge design and multifocal IOL are more prone to producing glare and haloSpherical aberration may produce some degree of distortion or glare under scotopic conditions when the pupil is dilated,even if the iris covers the edge of the lens optic

21Aspheric IOL may reduce some of these phenomena and improve contrast sensitivityTemporal dysphotopsia ,described as a dark or dim region or other subjective distortion in the temporal visual field,may be more common with square edge IOL and those manufactured from high-index materialGlistening visible in some early acrylic lenses were occasionally visually significantCalcium deposition within or on the surface of hydrophilic acrylic lenses has produced significant visual symptoms,leading in some cases to lens explantation

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