Management of Nucleus Drop

Phacoemulsification is becoming increasingly popular worldwide. It is a safe procedure, but complications are possible. Though complications such as shallow anterior chamber and hard eye have largely disappeared with the phasing out of conventional extracapsular cataract extraction (ECCE), newer complications such as the dropped nucleus have increased with the advent of phacoemulsification. This is potentially serious, as retained lens fragments can induce severe uveitis, secondary glaucoma and retinal detachment, all of which can lead to potentially serious visual loss.

Dislocation of the lens nucleus into the vitreous cavity is one of the most severe complications in cataract surgery. Incidence of nucleus drop into the vitreous cavity for phacoemulsification surgery varies between 0.3% and 1.1% depending on the surgeon’s experience. Retained nuclear material in the vitreous cavity can lead to severe complications like severe inflammation, intraocular pressure increase, cystoid macular oedema and retinal detachment. Risk factors for dropped nuclear fragments include: inexperienced surgeon, advanced age, undilated pupil, increased axial length, posterior polar cataract, hollow orbit, pseudoexfoliation, previous trauma and previous vitrectomy surgery.

Early recognition of posterior capsular rupture (PCR) and zonular disruptions with prevention of collapse of the anterior chamber (AC) may prevent extension of the tear, forward movement of the vitreous, and displacement of the lens posteriorly. Signs of PCR include instantaneous deepening of AC, difficulty in holding nuclear fragments with phacoemulsification tip, descent of the nucleus away from the phacoemulsification tip and momentary pupillary dilatation. In case of a PCR without the posterior dislocation of nuclear fragments, and without prolapse of the vitreous into the AC, the nuclear fragments can be removed by phacoemulsification, or by conversion to a conventional extracapsular technique, after injecting a viscoelastic substance behind the nuclear material.4 When vitreous is present at the AC, continued phacoemulsification can exert traction on the vitreous base, increasing the risk of retinal detachment. Under such circumstances, removal of the residual lens material should follow an initial anterior vitrectomy. If there is danger of posterior dislocation of lens fragments, a second instrument may be placed behind the fragment(s) to prevent intravitreal migration. Zonular disruption, due to trauma or pseudoexfoliation, may cause total lens dislocation with associated lens cortex and capsule.