**7. Multifocal lens**

These lenses have concentric ring segments that have two different focal lengths for distance and near vision.

#### **7.1. Toric lens**

cataract surgery with implantation of a posterior chamber IOL is 0.1–0.7% with an optimal

Complications for the ICL and PRL are similar and are related to the position of the pIOL between the rear surface of the iris and the front surface of the crystalline lens. Complications such as cataractogenesis, pupillary bloc, and glaucoma are due to pIOL design materials

antiseptic perioperative treatment regimen.

Loss of corneal endothelial cells Pupil ovalization/iris retraction

Surgically induced astigmatism

Chronic inflammation or uveitis

Optical quality, glare, halos

Surgically induced astigmatism Loss of corneal endothelial cells Pigment dispersion/lens deposits

Intraocular pressure elevation

*6.4.4. Complications of posterior chamber pIOL*

pIOL rotation

Oddities

Cataractogenesis Retinal detachment

(www.ecavolunteer.org). Optical quality, glare, halos

pIOL rotation

234 Advances in Eye Surgery

Oddities

Cataractogenesis Retinal detachment

Pigment dispersion or IOL deposits

Optical quality, glare, halos

*6.4.2. Complications of angle-supported anterior chamber pIOL*

Intraocular pressure elevation/pupillary block glaucoma

*6.4.3. Complications of iris-fixated anterior chamber pIOL*

These lenses have a cylindrical power to address astigmatism.

### **8. Conclusion**

The prevalence of refractive errors is high, affecting approximately one-third of persons 40 years or older in the United States and Western Europe. Myopia is the most common eye disease and is one of the leading causes of vision impairment.

This chapter describes current surgical techniques used to correct myopia, including laser correction (laser surgeries), incisional techniques, intrastromal corneal rings, pIOLs, and refractive lensectomy.

Spectacles and contact lenses remain the first choice for correcting refractive error, but refractive surgery, especially LASIK, is increasing significantly.

There are now several surgical techniques available for the treatment of myopia. The excimer laser, and pIOLs and RLE are promising tools for refractive surgery. The techniques are still developing, and it is certain that there will be significant advances in the future.
