Secondary intraocular lens implantation

Secondary intraocular lens (IOL) implantation is commonly required in post-traumatic scenarios, complicated cataract surgeries, and in congenital lenticular anomalies. In these scenarios, the capsular bag integrity is compromised, leading to the need of an alternative for IOL fixation.[1] Surgical interventions for secondary IOL implantation in recent times have been enhanced by the availability of a variety of devices and IOL placement strategies. These may be categorized in accordance with the position of the placement as anterior or posterior chamber secondary IOLs. Anterior chamber IOLs may be either angle-supported or iris-fixated anterior chamber IOLs, while posterior chamber ones can be retro iris-fixated or scleral-fixated posterior chamber IOLs. Meticulous preoperative evaluation inclusive of corneal endothelial status, anterior chamber iridocorneal angle, integrity of the iris and capsule, presence of vitreous in the anterior chamber, intraocular pressure, peripheral retinal evaluation, and the health of the macula and optic nerve needs to be done. Compromised corneal endothelial status, shallow anterior chamber angle, poor iris tissue support, and glaucoma preclude the choice of secondary angle-supported anterior chamber IOL implantation. Damaged iris tissue will also not favor anterior or retro-iris claw IOLs. Need for peripheral iridectomy in angle-supported IOLs is to be noted. Scleral-fixated sulcus placement of IOLs is not suitable in case of scleral abnormalities such as Marfan’s syndrome, scleral thinning, and in young children. There seemed to be little difference between the complication rates, visual acuity, and refractive outcomes of angle-fixated, iris-fixated, and transscleral-fixated IOLs.[2,3] Refractive surprises, residual cylindrical refractive errors, cystoid macular edema, glaucoma, endothelial decompensation and lens decentration, tilt, and dislocation remain significant concerns in secondary IOL implantations in the absence of adequate capsular support. A recent novel four-point, iris-fixated IOL claims to be successful in addressing aphakia and prevent angle closure glaucoma in eyes requiring secondary IOL implantation.[4] The planar configuration of single-piece IOLs causes a larger contact between the iris and IOL optics, while the thicker haptics of single-piece IOLs cause chronic chaffing of the posterior iris, resulting in uveitis–glaucoma–hyphema syndrome. Hence, single-piece IOLs are not to be placed in the sulcus as secondary implants in cases with favorable residual capsular support.[5,6] Various techniques have been described for transscleral fixation of posterior chamber secondary IOL implantation aided with either sutures (polypropylene or Gore-Tex sutures) or fibrin glue support.[7–9] Haptic extrusion, dislodgement, breakage, inadequate scleral tucking, and infection of sclerotomy site can complicate the surgery. Yamane technique[10,11] and its various modifications that utilize 27-gauge trocars instead of a needle to externalize the haptics and other methods show the popularity of sutureless transscleral fixation of secondary IOLs. The long-term follow-up results of these techniques will help us to understand the refractive outcome and complications associated with these modifications.[12] Careful patient selection, preoperative evaluation, surgical technique and its learning curve, and postoperative outcome and complications need to be revisited to analyze the risk–benefit relationship in these procedures.