Cataract surgery in a patient with subluxated lens due to trauma, zonular dialysis, or generalized weakness of zonules can be very challenging. Phacoemulsification, with or without inserting a capsular tension ring into the bag, can be used to remove cataracts in the presence of limited zonular support. In cases of severe lens subluxation and very limited zonular support, there are three approaches for this operation as follows. (1) The posterior approach via pars plana lens fragmentation. The disadvantage of this option is the need for posterior segment surgery and postoperative complications involved with posterior segment operations. (2) The anterior approach via cryo intracapsular cataract extraction (ICCE). This method is largely unused because of the large corneal incision needed and the high rate of intraoperative and postoperative complications. (3) The phacoemulsification approach using appropriate parameters depending on the grade of cataract. We propose an alternative method, using planned posterior assisted levitation (P-PAL) as a preferred approach to remove subluxated cataracts. Posterior assisted levitation (PAL) is a well-known emergency technique for managing an imminent dropped nucleus or lens during cataract surgery.[2–4]
Materials and Methods
Four eyes with severe subluxation of the crystalline lenses (i.e. 6 or more clock hours involved) [Fig. 1] and marked phacodonesis were included. Two eyes had history of blunt trauma, and the other two eyes had severe pseudoexfoliation (i.e. diffuse exfoliative material on the pupillary border and peripheral anterior lens capsule) with spontaneous lens subluxation [Table 1].
In all the cases, cataract surgery was performed under general anesthesia and all the procedures were performed by one surgeon. A 6 mm sclerocorneal tunnel incision was made about 2 mm behind the limbus. Two paracentesis side ports were made at the 3 and 9 o’clock meridian, and another side port was made at the 6 o’clock meridian for an anterior chamber maintainer (ACM).
A viscoelastic agent, Viscoat® (sodium hyaluronate 3.0%–chondroitin sulfate 4.0%; Alcon Laboratories, Inc., Fort Worth, TX, USA), was injected via the side port into the anterior chamber to protect the cornea and to minimize forward prolapse of vitreous into the anterior chamber. A disposable 1.3-mm, 20-gauge microvitreoretinal blade V-Lance knife (Alcon Surgical, Forth Worth, TX, USA) was used to perform a pars plana sclerotomy, 3.5 mm posterior to the limbus. Limited anterior chamber vitrectomy was used if needed. A 1-mm wide spatula (STORZ E706, Bausch and Lomb, Rochester, NY, USA) was inserted through this sclerotomy into the vitreal cavity and placed behind the lens. The lens (cum capsule) was pushed and lifted forward into the anterior chamber by the spatula [Fig. 2]. A sheet glide was introduced through the sclerocorneal tunnel incision and positioned under the lens and over the pupil to secure the lens in the anterior chamber, thus allowing safe removal of the spatula through the sclerotomy. The lens was then removed from the eye by gapping the sclerocorneal tunnel using an ACM [Fig. 3]. The sclerocorneal tunnel was enlarged till 7.5 mm (case 1) or 8 mm (cases 2–4). Anterior vitrectomy was performed after lens delivery through the paracentesis incision at the limbus to remove any vitreous that was present in the anterior chamber. The sclerotomy was closed with a single interrupted 7-0 polyglactin (Vicryl) suture. An anterior chamber IOL was implanted in all cases, and peripheral iridectomy (PI) was performed [Fig. 4]. The scleral tunnel was sutured with several 10/0 nylon sutures.
The postoperative follow-up ranged from 1 to 2 years in three cases. Patient 3 died 1 month after surgery from causes unrelated to the procedure. The best corrected visual acuity (BCVA) at the last follow-up visit was 20/80 or better in all eyes. There were only slight early postoperative complications, including transient high intraocular pressure (IOP) (52 mm Hg), corneal erosion, and mild diffused vitreous hemorrhage, which all resolved within a few days after the operations. No retinal tears, holes or detachment were identified by biomicroscopy and indirect ophthalmoscopy during the follow-up period [Table 1].
In adults, subluxated cataracts may be accompanied by a rock-hard nucleus with pseudoexfoliation or a history of traumatized eye which can make removal of the lens from the eye very challenging.
In 1978, Kanski described intracapsular cryoextraction associated with anterior vitrectomy in four cases. In 1979, Peyman et al. used a cryoprobe through a limbal incision and vitrectomy. In subsequent years, pars plana and/or limbal lensectomy and vitrectomy associated with IOL implantation in the anterior chamber were used. In 1999, Lee et al. advocated intracapsular cataract extraction and anterior chamber IOL implantation, while Tsai et al. proposed pars plana lensectomy followed by transscleral fixation of a foldable IOL. Several complications were reported, such as retinal detachment, massive vitreous loss, expulsive hemorrhage, and lens loss into the vitreous cavity. Recently, the use of a capsular tension ring with one or two fixation eyelets for suture fixation, or a capsular tension segment to ensure capsular bag stabilization, has been suggested in cases of more profound zonular weakness. Also, recently, combined pars plana phacofragmentation, vitrectomy, and Artisan lens implantation has been described for traumatic subluxated cataracts.
PAL was first described by Packard et al. and Kelman for managing an imminent dropped nucleus. As an emergency procedure, PAL appears to be a safe procedure with no serious intraoperative or postoperative complications and with good visual rehabilitation. Lifshitz et al. reported the long-term outcome of PAL in seven cases of a sinking dropped nucleus during phacoemulsification. In their report, postoperative visual acuity was 20/40 or better in all but two eyes. No postoperative retinal detachment, retinal tears or other complications were observed.
Chang et al. described a modified PAL technique using sodium hyaluronate 3.0%–chondroitin sulfate 4.0% (Viscoat®) in eight eyes and provided postoperative clinical data. Postoperative visual acuity was 20/40 or better in all but one eye. Recently, Por et al. described the use of PAL technique accomplished by the pars plana insertion of a needle, in 3 cases of dropped nucleus/nuclear fragments, 1 case of intraoperative subluxated posterior chamber intraocular lens (PC IOL), and 10 cases of late subluxated PC IOLs. One case of retinal detachment occurred 20 months after PAL. BCVA was 20/40 or better in all except three cases.
An important concern regarding PAL is the possibility of vitreous traction and retinal tears resulting in postoperative retinal detachments. Within the limitation of our case series, to date we have no cases of retinal holes, tears or detachment after planned PAL. Many surgeons, particularly in the West, may be no longer skilled in nuclear expression technique, although in our opinion every cataract surgeon may be familiarized with it because not every cataract case is suitable for phacoemulsification.
To our knowledge, we are the first to report P-PAL as a planned procedure for extracting severe subluxated cataracts. We successfully used P-PAL in four eyes with extreme zonular dialysis, marked phacodonesis with generalized weakness of zonules due to trauma or severe pseudoexfoliation.
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Source of Support: Nil.
Conflict of Interest: None declared.