The recommended surgical strategy for eyes with preexisting posterior capsule defect is to provide a protective cortex cushion during nucleus removal by avoiding corticalcleaving hydrodissection and rotation of the nucleus[1,2]. With conventional hydrodissection, there is a high risk of enlarging the preexisting rupture and subsequently dropping lens materials into the vitreous. This can be avoided by the "insideout hydrodelineation" technique, where the fluid is precisely injected between the cortex and the nucleus, after sculpting a deep groove in the middle of the lens.
A 54yearold woman underwent pars plana vitrectomy on the right eye for diabetic retinopathy. Soon after surgery, her vision deteriorated and the lens became opaque. Slitlamp examination revealed a ruptured posterior capsule and lens pearls bulging into the vitreous through the posterior capsule defect (Figure 1).
Figure 1Ruptured posterior capsule and lens pearls bulging into the vitreous just behind the lens.
Surgical Technique After topical anaesthesia, the anterior chamber was filled up with ophthalmic viscosurgical device and a continuous curvilinear capsulorhexis was performed with forceps. We avoided hydrodissection and rotation of the nucleus. With very low vacuum, a central trench was sculpted.
Delineation was performed through the groove by gently injecting fluid from inside to outside, following the technique of Vasavada et al. The central nucleus and the epinucleus were easily removed. The remaining cortex bowl gave protection and safety for the posterior capsule during the whole procedure. Unfortunately, because of the extension of posterior capsule lesion to the periphery during cortex removal, we could not convert the preexisting lesion to a continuous posterior capsular rhexis, which was our original plan, and would have been the ideal solution. Because of this, we implanted the posterior chamber intraocular lens (PCIOL) in the ciliary sulcus, instead of the capsular bag.
Posterior capsule weakness can be found among infants and small children with congenital posterior polar cataract, where an existing defect in the posterior capsule is well known[4,5]. Posterior polar cataracts in adults also present greater surgical risk, and therefore should be differentiated from posterior cortical cataract. Other types of preexisting posterior capsule breaks were observed after perforating ocular injury, and in traumatic cataract with intact anterior capsule .
Direct mechanical injury of the posterior lens capsule in vitrectomized eyes occurs rarely. We could not find any case mentioned in the literature, despite the fact that it is not entirely unlikely when cataract develops shortly after pars plana vitrectomy.
The anatomical situation in this case is worse compared to the posterior polar cataract, because there is no surrounding round intact posterior capsular rim, but vitreous lenticular support is also absent, thereby increasing the risk of dropping the nucleus.
Our case can be considered successful as no dropped nucleus ocurred despite the preexisting posterior capsule defect, and because a PCIOL could be implanted, although ideally it would have been preferable if the posterior capsule defect had been converted to a posterior capsulorhexis and the PCIOL had been implanted into the capsular bag.
Accurate diagnosis by meticulous examination after maximal mydriasis, and a detailed discussion with the patient are required to successfull care for a patient with a preexisting posterior capsule defect. Early intervention is preferred before the lens becomes denser or mature, requiring more phaco power and worsening visualisation during surgery. Furthermore, spontaneous nucleus drop may occur due to enlargement of the (originally usually tiny) posterior capsule defect from swelling of the cristalline lens.
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