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Progress is being made in dealing with Marfan's syndrome, but careful surgical planning decisions are still necessary
Safe positioning of an intraocular lens (IOL) after lentectomy in hereditary ectopia lentis has been achieved by various techniques including iris fixation by clipping or suturing, anterior chamber IOL with chamber‐angle support and transscleral suturing of a posterior chamber IOL. None of these approaches requires preservation of the capsular bag, and they are regularly combined with an anterior vitrectomy. However, the loss of separation between the anterior and posterior compartment of the eye may make a key contribution to subsequent complications such as retinal detachment, macular oedema or even glaucoma. From an anatomical point of view, the surgical approach proposed by Cionni et al1,2 and now studied by Bahar et al3(see page 1477), in a series of adult patients with hereditary lens subluxation owing to Marfan's syndrome, would seem to represent progress compared with traditional lentectomy with anterior vitrectomy and implantation of an anterior chamber lens. The implantation of the IOL in the transsclerally fixated capsular bag does not compromise the endothelial cell count over the years and should also cause less chronic anterior chamber irritation than is induced by the different anterior chamber IOLs. The preservation of an anterior and posterior compartment should also reduce the probability of retinal problems and make any subsequent glaucoma or vitreoretinal interventions easier, although naturally no sufficiently valid long‐term data are available as yet.
However, some limitations of this very demanding surgical approach should be borne in mind by the interested cataract surgeon. In Marfan's syndrome, the anterior continuous curvilinear capsulorhexis may be complicated by the extremely subluxated lens and an incomplete mydriasis, leading to a relatively small and excentric capsulorhexis. Additionally, damage to the capsular bag may occur when iris hooks are used to stabilise the capsular bag position or during suturing of the tension ring or other surgical manoeuvres.4,5 Any tearing or notching of the anterior continuous curvilinear capsulorhexis or defect in the capsular bag should be primarily considered as a contraindication for the relatively rigid capsular tension ring made of polymethyl methacrylate, because rupture of the whole capsular bag can be induced during or after implantation of the tension ring owing to the strong mechanical forces acting on the capsular bag. Especially in young children with Marfan's syndrome, who were not the focus of Bahar et al's study, there is the added problem that the Cionni ring, with its fixed size and rigidity, may not fit a malformed or even colobomatous infantile lens, thus increasing the risk of accidental rupture of the capsular bag during surgical manoeuvres. A valuable surgical alternative in these cases could be the use of differently sized capsular tension ring segments with fixation eyelets, as proposed by Hasanee and co‐workers.6 This approach simplifies implantation while minimising mechanical stresses on the capsular bag and the loosened zonulae. Regardless of the devices used, the correct placement and suturing of the fixation eyelets requires an intact and sufficiently large anterior capsulorhexis, a very experienced surgeon and sufficient patience for a relatively time‐consuming procedure compared with conventional IOL implantation. It should also be noted that little is known about possible long‐term problems with the non‐resorbable suture securing the Cionni ring—or, for that matter, with sclerally sutured IOLs—in young patients. Theoretically, the lifetime of these sutures should be long enough, but Cionni and co‐workers have reported an incidence of nearly 10% for broken sutures after a median follow‐up of 18 months, leading to their recommendation that sutures stronger than Prolene 10‐0 be used.2 In practice, even Prolene sutures well buried in the sclera can become visible after years and can even cause conjunctival erosion and possible suture‐induced infection.
With so many questions remaining unanswered, we have to acknowledge that many options—even visual rehabilitation with contact lenses or glasses rather than IOL7—can produce satisfactory long‐term results after lentectomy in hereditary lens subluxation, and we would recommend that decisions on surgical planning be made on an individual basis.
IOL - intraocular lens