**4. Conclusions**

*Intraocular Lens*

*3.2.2 Limitations and possible complications of refractive lens exchange*

(axial length adjusted) should be used [88, 89].

can still accommodate.

possible [92].

The commonest disadvantage is the loss of accommodation with the need for near-vision glasses in the cases of monofocal IOL and the inherent risk associated with intraocular surgery, especially in high myopes [80]. The risk for endophthalmitis in general cataract surgery with implantation of a posterior chamber IOL is 0.1–0.7% with an optimal antiseptic perioperative treatment regimen [87]. Lens surgery is significantly more challenging in a highly myopic eye for several reasons. The issues that we take for granted in an eye of normal length (22–25 mm) such as the accuracy of axial length measurements and the choice of lens formula become a significant issue in the highly myopic eye as the predicted refractive outcomes are not achieved consistently. Axial length measurement error has been largely overcome by the use of optical interferometry. Despite this, consistent hyperopic errors are still reported. Improved predictive results are obtained with the Barrett Universal II (software constants), Haigis (ULIB), SRK/T, Holladay 2 (software constants), and Olsen (software constants) formulas in eyes with axial lengths greater than 26.0 mm and IOL powers greater than 6.0 D. In the eyes with axial lengths greater than 26.0 mm and IOL less than 6.00 D, the Barrett Universal II formula (software constants) and the Haigis (axial length adjusted) and Holladay 1 formulas

Intraoperatively, a highly myopic eye is surgically more challenging as the anterior chamber is deeper, with a floppy and large capsular bag and occasionally zonular weakness [90]. The anterior chamber is often unstable, and it is even less stable in a previously vitrectomized high myopic patient. There is also a concern that with elongated axial lengths, there is a higher risk of bag instability that can cause impaired vision, and the more complicated the IOL design is, the more sensitive the IOL is to final centration. A study by Soda et al. found that in uncomplicated cataract surgery with an IOL in the bag, the maximum decentration can be 0.3 mm for a satisfying result [91]. In addition, it is reported that myopic patients may exhibit worse results with more reported subjective symptoms and measurable aberrations like coma and glare in mesopic and scotopic lighting conditions compared to non-myopic controls, after multifocal IOL implantation with approximately the same amount of decentration [91]. RLE may increase the risk for retinal detachment and is generally not considered in myopic pre-presbyopic patients who

The incidence of retinal detachment is especially high among younger age groups (<50 years) and in the eyes with long axial length > 26 mm. The reported incidence of retinal detachment after RLE ranges from 2 to 8%. Meticulous surgery with minimal intraoperative vitreous disturbance and a regular follow-up postoperatively until the occurrence of posterior vitreous detachment can reduce the risk of retinal detachment further. With the higher risk of retinal detachment in younger patients, it is prudent to defer RLE in patients younger than 40 years if

Other possible causes of unfavorable visual outcome after uncomplicated phacoemulsification are cystoid macular edema (CME) and choroidal neovascular membrane (CNVM). Overall incidence of subclinical CME diagnosed with optical coherence tomography (OCT) is 5%, and incidence of clinical CME is 3%; however, high myopia does not increase the risk of CME [93]. Reported incidence of CNVM after RLE for myopia is 12.5% [94]; however, whether this was related to the higher degree of myopia with preexisting lacquer crack that was missed or due to some inflammatory mediators and free radicals released after surgery cannot be conclusively proved. Because the reported incidence of CNVM after uncomplicated phacoemulsification is not high, we assume that it is secondary to the degree of myopia,

**112**

Surgical treatment of myopia is a viable, safe, efficient, and predictable method for treating patients with myopia. There are several options of surgical treatment; we as doctors must always use our best judgment and available data to make sure we recommend the best method for each patient and their respective needs while taking into account any possible risk and contraindications. Among elective procedures in medicine, myopia treatment is one of the most commonly performed surgeries because of the positive effect it brings the patients' quality of life.
