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Editor,—Silicone oil is useful in the treatment of some cases of retinal detachment with severe proliferative vitreoretinopathy.1 With prolonged silicone lens contact, a permanent cataract will form in all cases.2 3 In order to reduce the incidence of postoperative complications in silicone filled eyes, many authors recommend that silicone oil should be removed from the eye as soon as a stable retinal situation is achieved.1 2 4-6
We performed phacoemulsification and silicone oil removal through a planned posterior capsulorhexis.
The retrospective study included 10 patients with proliferative vitreoretinopathy, seven females and three males, ranging in age from 12 to 82 years. Pars plana vitrectomy, membrane peeling, encircling band, and silicone oil tamponade were performed 6 months before removal of the silicone oil. The mean refractive error was −2.50 dioptres (range −10 to 0.50 dioptres).
Conventional phacoemulsification was performed and a central posterior capsulorhexis was performed using the capsulorhexis forceps. Silicone oil was removed through the posterior capsulorhexis with the irrigation-aspiration handpiece and the corneal incision was not widened. In eight patients soft acrylic foldable lenses were implanted in the capsular bag. Two patients received an heparin modified poly(methylmethacrylate) lens, one into the capsular bag and one in the sulcus.
The preoperative intraocular lens (IOL) power calculation was performed with the modified SRKII formula, using the axial length of the fellow eye.
The mean follow up period after cataract surgery was 7.5 months. Prolapse of the iris and loss of the iris pigment epithelium did not occur during surgery. One posterior capsular rupture occurred during hydrodissection.
Two cases of transient postoperative corneal oedema were noted. One of the patients had recurrence of his retinal detachment 1 month after silicone oil removal. This patient underwent successful reattachment after silicone oil endotamponade.
The visual acuity improved in nine of the 10 eyes. Nine eyes achieved a best corrected visual acuity of 0.4 or better.
The postoperative refraction was more myopic than predicted by an average of 1.7 dioptres.
Silicone oil can cause anterior segment complications.1 4 7 There is evidence that these complications can be prevented by its early removal.2 6Removal of silicone oil combined with cataract extraction reduces the number of surgical procedures.
After silicone oil removal the eyes were hypotonic during surgery. Foldable IOLs were implanted in eight eyes to reduce postoperative astigmatism. Silicone oil was observed to be adherent to the silicone IOL surface,8 for this reason we prefer implantation with the Acrysof IOL (Alcon).
Unpredictable refraction in eyes filled with silicone oil is the main problem. The use of specific sound velocities to calculate axial length has been proposed.9
Jonas and coworkers first reported cataract surgery combined with transpupillary silicone oil removal through planned posterior capsulotomy.10 They removed the silicone oil by an essentially passive technique. The main difficulty of this technique was the prolapse of the iris. In our technique there was no widening of the corneal incision and iris prolapse did not occur. This technique avoided contamination of the operative field with the silicone oil. This method did not permit additional membrane peeling or retinal stabilisation and must be reserved for cases of stable retina with no or few recurrent membranes and closed retinal breaks.
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