**5. Lenticular refractive surgery**

Phakic IOLs for the treatment of myopia work by diverging light rays so light rays from a distant object are focused sharply on the retina rather than in front of the retina. Phakic IOLs, therefore, can be inserted in the anterior chamber of the eye in front of the iris or placed in the posterior chamber of the eye behind the iris in front of the natural lens in the ciliary sulcus (www.meddpagetoday.com).

#### **5.1. Refractive lens exchange**

This is extraction of the natural lens and insertion of a posterior chamber IOL, that is, "cataract surgery" in the absence of a visually significant cataract.

The technique is a variety of standard cataract surgery. The elements involved are the transparency and softness of the crystalline lens in the absence of cataract and the elongation of the globe, an axial length of ≥26.5 mm associated to high myopia, which in this particular case is the indication for RLE [10].

The ideal technical elements for successful RLE surgery include the following [10]:


Special considerations in cases selected for RLE include the following:

The best approach to RLE surgery includes minimally invasive surgery, through the smallest possible incision.

Specific informed consent for RLE different to different to the one used for cataract surgery must be provided and will include information about potential refractive benefits and complications, and the problem of pseudophakic presbyopia [10].

#### **5.2. Surgical technique [10]**

#### *5.2.1. Topical anesthesia*

A clear corneal incision and continuous curvilinear capsulorhexis (CCC)

Hydrodissection: cortical cleaving hydrodissection is performed in two separate distal quadrants with decompression of the anterior chamber in order to avoid capsular block syndrome

Prechopping (optional): although the nucleus is not hard in RLE, prechopping facilitates further surgical maneuvers and reduces surgical time

#### *5.2.2. Phacoemulsification*

The nucleus is divided based on the technique used: prechopping, chopping, or grooving,

Irrigation/aspiration

An adequate viscoelastic is injected deep in the capsular bag to reform the bag and prepare it for IOL insertion

IOL insertion. After IOL insertion, bimanual

Irrigation/aspiration is performed to remove all viscoelastic material

A preservative-free antibiotic is injected into the anterior chamber, and then the stroma at the incisions is hydrated to assist self-sealing.

#### *5.2.3. Complications*

Post-RLE retinal detachment

Cystoid macular edema in the first few weeks after surgery

PCO, which can develop from months to years after the surgical procedure

A decrease in twilight vision (with halo perception and glare) after implantation of multifocal IOLs.

Choroidal neovascular membrane (CNV) formation

Myopic macular degeneration

RLE is indicated in high refractive error in the absence of cataract. RLE, however, is specifically only indicated in presbyopic eye [10]. In general, due to the fact that at present for restoration of near intermediate, and distance vision, multifocal IOLs are at present superior to the available accommodating IOLs. The main challenge involved is to reach emmetropia with rapid recovery using the astigmatically neutral incisions of modern cataract surgery [10].
