Desire for a life free of spectacle and contact lens correction is not limited to low and mod- erate myopes under the age of 40. The high myope with accommodative reserve may be a good candidate for phakic refractive lens im- plantation, and the presbyopic hyperope has become well recognized as a candidate for re- fractive lens exchange with an accommodat- ing or multifocal intraocular lens (IOL) [1].
The myope over the age of 45, however, may be greeted with skepticism. Surgeons worry that presbyopic low myopes will not be satis- fied with a simple trade of distance correc- tion for near after bilateral laser-assisted in- situ keratomileusis (LASIK) or a compromise of depth perception with monovision, while a multifocal or accommodating IOL may not offer the same quality of near vision they al- ready have without correction. Refractive lens exchange for moderate to high myopes may raise concerns about significant compli-
cations, especially retinal detachment. In par- ticular, eyes with long axial length and vitre- oretinal changes consistent with axial myopia may be at higher risk for retinal detachment following lens extraction and IOL implanta- tion. A review of the published literature is helpful in the evaluation of this risk.
In an oft-cited study, Colin and colleagues have reported an incidence of retinal detach- ment of 8.1% after 7 years in high myopes (>12 D) undergoing refractive lens exchange [2]. Colin’s case series includes 49 eyes with a total of four retinal detachments. The first occurred in a male with an axial length of 30 mm and preoperative myopia of –20 D who required preoperative argon laser pro- phylaxis for peripheral retinal pathology and underwent refractive lens exchange at 30 years of age. His retinal detachment occurred 18 months after his lens surgery. The other three retinal detachments occurred following
Refractive Lens Exchange in High Myopia:
Weighing the Risks
Mark Packer, Richard S. Hoffman, I. Howard Fine
CORE MESSAGES
2 Eyes with long axial length and vitreoretinal changes consistent with axial myopia may be at higher risk for retinal detachment fol- lowing lens extraction and intraocular lens implantation.
2 Minimizing risk is critical to the success of refractive lens exchange and refractive surgery in general, since these are entirely elective procedures.
2 The published literature supports an acceptable safety profile for refractive lens exchange in high myopia.
26
YAG laser capsulotomy. These two patients were 8–9 years older than the first, and their eyes were not as extremely myopic, did not have preoperative retinal pathology and suf- fered retinal detachment 5.5–6 years after lens surgery and 1–2 years after YAG capsulo- tomy.
A striking feature of Colin’s paper is the re- lationship of YAG capsulotomy to retinal de- tachment. Ranta and colleagues recently demonstrated that each millimeter increase in axial length increases the risk of retinal de- tachment after YAG capsulotomy by a factor of 1.5 [3]. Their findings also support the con- clusion that about half of retinal detachments that occur after YAG result from new lesions (horseshoe tears), while the other half result from “potentially antecedent small atrophic holes.” Unfortunately, preoperative prophy- laxis cannot address the former. The statisti- cal methodology of this study represents a good model for further research in that it quantifies risk in terms of axial length rather than diopters of myopia. To our knowledge no one has suggested additional risk for reti- nal detachment to extremely steep keratome- try.
A review of the literature to help deter- mine the actual risk of retinal detachment af- ter lens surgery should be limited as much as possible to current techniques, such as small- incision lens extraction, capsulorrhexis and in-the-bag IOL placement. Sanders has re- cently pointed out that some of the publica- tions cited in the literature employed tech- niques no longer representative of the standard of care [4]. For example, Javitt [5] as- sumed an ultimate rate of retinal detachment of 7.5% based on the earlier work of Barra- quer. However, Barraquer’s series included 3% intracapsular lens extractions, while only nine of 165 eyes in his series received an IOL [6]. Sanders suggests that the 1,372 subjects of 14 peer-reviewed articles who underwent re- fractive lens exchange by phacoemulsification with posterior chamber IOL implantation comprise a more pertinent comparison
group. Retinal detachments in this group numbered 14, for a cumulative rate of 1%.
A still more recent publication by Fernan- dez-Vega reports a retrospective case series of 190 eyes of 107 patients with a minimum axi- al length of 26.00 mm that underwent refrac- tive lens exchange with posterior chamber IOL implantation and had a mean follow-up of 4.78 years (3.1–8.03 years) [7]. The surgical technique involved capsulorrhexis, hydrodis- section, phacoemulsification and insertion of a one-piece polymethylmethacrylate (PMMA) IOL through an enlarged 6.5-mm incision with suture closure as needed. The reported YAG capsulotomy rate was 77.89% (148 eyes).
Retinal detachment developed in four eyes with a mean axial length of 30.44 mm (29.60–32.30 mm), all of which had under- gone YAG capsulotomy. The overall incidence of retinal detachment was 2.1%.
The question arises as to the natural inci- dence of retinal detachment in high myopia without surgical intervention. An oft-quoted figure is 0.68% per year for myopia greater than –10 D [8]. This rate amounts to 3.25%
over the 4.78-year mean follow-up period of the series studied by Fernandez-Vega. Their reported rate of 2.1% for eyes undergoing refractive lens exchange actually compares favorably with the rate for unoperated eyes, as does the cumulative 1% rate quoted by Sanders.
Minimizing risk is critical to the success of refractive lens exchange and refractive sur- gery in general, since these are entirely elec- tive procedures. Several conclusions emerge from the literature on retinal detachment fol- lowing refractive lens exchange. First, careful preoperative examination and counseling should precede any decision to operate. Com- plete funduscopic examination with scleral depression and determination of the state of the vitreous body comprise essential steps in the examination. Referral to a vitreoretinal specialist should be entertained if any doubt emerges about the nature of a lesion or the indication for prophylaxis.
234 M. Packer · R. S. Hoffman · I. H. Fine
Second, surgical principles should empha- size minimal disturbance of the intraocular environment. Microincision techniques facil- itate maintenance of a stable chamber, construction of a round and centered capsu- lorrhexis, effective cortical cleaving hydro- dissection, efficient aspiration of lens materi- al without application of ultrasound energy, and safe bimanual cortical clean-up through two paracentesis-type incisions. A fresh tem- poral clear corneal incision may be con- structed for introduction of the IOL. All inci- sions should be Seidel negative at the conclusion of the case.
Third, eventual YAG capsulotomy should be avoided if possible. The construction of a capsulorrhexis that completely overlies the edge of the IOL optic, the use of cortical cleaving hydrodissection, meticulous cortical clean-up and the implantation of an IOL with a sharp posterior edge all facilitate mainte- nance of a clear posterior capsule.
By following these guidelines, we may be able to improve on the outcomes recently re- ported by Fernandez-Vega. It is equally en- couraging that none of the eyes that did expe- rience a retinal detachment in that series lost a line of best corrected visual acuity. Careful patient selection and follow-up will always contribute to improved results. For now, the published literature supports an acceptable safety profile for refractive lens exchange in high myopia. This procedure, with the im- plantation of an accommodative or multifo- cal IOL and the use of concomitant limbal re- laxing incisions, can also successfully address astigmatism and presbyopia among the high- ly myopic population.
References
1. Packer M, Fine IH, Hoffman RS (2002) Refrac- tive lens exchange with the Array multifocal lens. J Cataract Refract Surg 28:421-424 2. Colin J, Robinet A, Cochener B (1999) Retinal
detachment after clear lens extraction for high myopia. Ophthalmology 106:2281–2285 3. Ranta P, Tommila P, Kivela T (2004) Retinal
breaks and detachment after neodymium:YAG laser posterior capsulotomy: five-year inci- dence in a prospective cohort. J Cataract Re- fract Surg 30:58–66
4. Sanders DR (2003) Actual and theoretical risks for visual loss following use of the implantable contact lens for moderate to high myopia.
J Cataract Refract Surg 29:1323–1332
5. Javitt J (1994) Clear-lens extraction for high myopia. Is this an idea whose time has come?
(Editorial) Arch Ophthalmol 112:321–323 6. Barraquer C, Cavelier C, Mejia LF (1994) Inci-
dence of retinal detachment following clear- lens extraction in myopic patients: retrospec- tive analysis. Arch Ophthalmol 112:336–339 7. Fernandez-Vega L, Alfonso JF, Villacampa T
(2003) Clear lens extraction for the correction of high myopia. Ophthalmology 110:2349–
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8. Perkins ES (1979) Morbidity from myopia.
Sight Saving Rev 49:11–19
Chapter 26 Refractive Lens Exchange in High Myopia 235
