spektrum der augenheilkunde - 150 Jahre Augenklinik Graz

eview articlemies were first introduced in the 1930s by Sato for thecorrection of myopia [ 1 ].The implantation of an artificial lens into the eye tocorrect a refractive error was first described by Strampelliin 1953 [ 2 ]. This procedure was also performed by Barraquerand Choyce in the 1950s, but because of the weakunderstanding of the anatomical structures of the anteriorsegment of the eye and imperfect intraocular lens(IOL) designs, the implantation of phakic IOLs revealeda high complication rate including endothelial cell loss,cataract and glaucoma. They were therefore abandoneduntil the late 1980s, when George Baikoff introduced ahighly advanced angle supported phakic IOL for the correctionof myopia [ 3 ].The renaissance of phakic IOLs in the 1980s was basedon better understanding of the anatomical structures ofthe eye, better IOL materials and especially better IOLdesigns [4 ].Two different kinds of anterior chamber phakic IOLswere presented in the mid 1980s.George Baikoff introduced the angle supported ZBlens [ 3 ] , and Fechner and Worst developed the iris-clawphakic IOL [ 5 ]. Both lenses were made of PMMA materialand underwent several improvements until themillennium.It was also in 1986, when Fyodorov introduced thefirst model of a posterior chamber phakic IOL [ 4 ]. But theFyodorov lens had a high complication rate for uveitisand cataract formation. The lens was then further developedand became the prototype of the Visian ICL (STAARSurgical, Co, Monrovia, USA).Th is review gives a short overview about the differenttypes of phakic IOLs, which are CE marked, FDAapproved or under consideration for approval.Anterior chamber phakic IOLsAngle-supported phakic IOLs revealed a renaissance inthe 1980s and George Baikoff was one of the first designersof the new lenses in the late 1980s. However, complicationrate was high and around 80 % of the first generationZB-type Baikoff phakic IOL had to be explanted [ 6 ].Several angle-supported anterior chamber phakicIOLs were then developed in the 1990s. Whereas, theIOL materials were made of polymethylmethacrylate(PMMA) in the 1990s, the models coming up at the beginningof the twenty-first century were made of hydrophilicor hydrophobic acrylic material [ 7 , 8 ].Th e PMMA angle-supported phakic IOLs showedgood post-operative refractive results including stability.The average post-operative spherical equivalent was− 1.8 D one year after phakic IOL implantation [ 9 ]. To ourknowledge all phakic IOL of the ZB and ZSAL series werewithdrawn from the marked due to the high complicationrate including cataract formation (10 %) and pupil ovalisation(35 %) [ 9 ] (Fig. 1 ). Endothelial cell count droppedon average from 3,000 to 2,000 cells/mm 2 during the follow-upperiod of 12 years [ 9 , 10 ] and pupil ovalisation hasFig. 1 Mild pupil ovalisation in an eye with a NuVita MA20(Bausch & Lomb, USA) angle supported phakic IOLbeen shown to be related to iris ischemia and is thereforenot only a cosmetic problem for the patient [ 10 ].One of the main disadvantages and problems of anglesupportedphakic IOLs was/is the sizing of these lensesand exact measurement of the internal angle-angle distanceis mandatory. Most of these IOLs were availablebetween 12.0 and 13.5 mm.The standard calculation of the phakic IOL size wasand still is based on the nasal to temporal white-to-whitedistance plus 1.0 mm, but this distance does not alwaysrepresent the real internal distance. Undersizing of anangle-supported phakic IOL leads to IOL decentration,IOL rotation and chronic endothelial cell loss. Oversizingof the angle-supported phakic IOL leads to a high pressureon the iris roots and can result in pupil ovalisation due toiris ischemia, if the lens is made of PMMA material [ 10 ].To reduce the incision site for phakic IOL implantation,several types and designs of angle supported phakicIOLs made of foldable material were introduced aroundthe Millennium.Phakic IOLs made of foldable material have the advantageof an implantation through a small corneal or corneo-scleralincision, which gives us a better calculationof the post-operative refraction, especially astigmatism.These IOLs can be implanted through a 3.0 mm incision.The second advantage was the low rate of pupil ovalisation.However, these lenses developed a vaulting in casesof oversizing and the distance between the IOL and cornealendothelium was less than 1.0 mm in a high numberof eyes, which resulted in severe endothelial cell loss ofthe cornea [7 , 10 ] (Figs. 2 , 3 ).All kinds of angle supported phakic IOLs made ofhydrophilic acrylic materials (ICARE, Vivarte, New-Life) were withdrawn from the market, after the Frenchauthorities suspended commercialisation in 2007 [ 7 , 11 ],since these IOLs induced a high rate of endothelial cellloss [ 7 ]. In cases of endothelial cell loss of more than 30 %or an endothelial cell density of less than 1,500 cells/mm 2 , the phakic IOL should be explanted owing to the1 3Phakic intraocular lenses: past and present 275