Since around 1950s,researche shave been researchin goninsertingintraocular lenses.The primary goalof these researches was for cataract patients to use intraocular lenses,instead of thick glasses that they had to wear after removing their cloudedcrystalline lens by cataracts surgery. These lenses were made of silicon orplastic (PMMA), which did not show any rejection or foreignbody reaction.Nowadays, these intraocular lenses can be implanted inside the eye, without removing the naturallens of thepatient,to correctmyopia, hyperopia and intenseastigmatism.The difference between this method and placing the intraocular lensduring cataract surgery is that inthis method the natural crystalline lensofthe eye remainsintact, and only one additionallensis place dinfront of it, whereas in cataract surgery thenaturallensof the eyeis removed andreplaced byan artificiallens. Therefore, in the intraocular implant method, the lens is able to changeits focus, allowing near and distance vision, while in cataracts surgery it is not possible (unless multifocal lenses are used). However, this technique is not a good alternative for LASIK or PRK for low eye scores, but for higher scores, itshould be taken into account.
There are different types of intraocular lenses;some are placed in the anterior chamber of the eye (behind the cornea and in front of the iris – the colored part of the eye) and some of them in the posterior chamber of the eye (on the natural crystalline lensand behind the iris).Each of these types has its own advantages and disadvantages, and it seems that Artisan lens,which is used in Noor eye clinic, has the best design.This lensis designed by Doctor Jan Worst andismade of PMMA.It is supported by two flexible haptic "claws" for iris fixation, and it is placed at a safe distance from the corneal endothelium.This lens can be used to correct myopia, hyperopia and extreme astigmatism which cannot be correctedby laser procedure.So far, about 150,000 of these lenses have been used to correct refractive errors all over the world.This lens is inserted inside the eye on a permanent basis, but it can be surgically removedat any time.
The procedure is performed in an operating theatre, but an in-patient hospital stay is not necessary before or after the surgery. After the eye is numbed, usually by general anaesthesia, a small incision is made in the cornea. The lens is inserted into the anterior chamber,in front of the natural crystalline lens of the eye, through this incision. Once the lens is situated precisely in front of the cornea, the incision is sutureddelicately.Sutures are removed after 4 to 6 weeks .A few days after surgery, the patient may feel a slight pain and the patient's final vision will be postponed until pulling of sutures .No sutures are required in the case of Artiflex lenses(foldable version of Artisan).Another type of foldable lenses is ICL which is inserted into the eye without any sutures.Unlike the Artisan lens, ICL is placed into the posterior chamber, behind the iris and in front of the natural crystalline lens of the eye.
A better than 20/40 vision is expected in the 97% of the cases which, by using spectacles ,this rate can increase to 100% and the average postoperative vision has been 20/30.These implantable contact lenses can be used to correct short-sight (from -3D to -23D) and considering that the maximum extent of myopia which is usually treatable by LASIK is around 12 dioptres, It can be seen that for some people, the only way to correct myopia, is using intraocular lenses. Moreover, these lenses can be used for patients who can't have a laser surgery, due to their excessively thin corneas.