Background: Compared to other refractive surgeries, implantation of phakic intraocular lenses (pIOLs) have more desirable results and are potentially reversible procedures due to the possibility of explanting these lenses. These methods usually do not require expensive or special surgical equipment and most ophthalmologists are able to perform these procedures; however disabilities resulting from pIOLs are more severe compared to corneal refractive surgery. Due to the potential risk of damage to anterior segment structures, especially corneal endothelial cell loss.
Aim of the Work: to compare between anterior chamber (AC) pIOL and posterior chamber (PC) pIOL in patients with myopia as regard:
1- Uncorrected and best corrected visual acuity (UCVA & BCVA).
2- IOP(Intra ocular pressure).
3- Endothelial cell count (ECC).
4- Postoperative inflammation and complications.
Patients and Methods: This prospective comparative study included 30 eyes of patients suffering from high myopia at Al-Hussein University Hospital from 2017 to 2018. The patients were divided into two groups:
Group (A): included (15) eyes where Polymethyl methacrylate (PMMA) iris-fixated AC pIOL were implanted (Artisan). Group (B): included (15) eyes where the PC pIOL were implanted (Implantable CollamerLens (ICL V4).
In this study we did pre and postoperative specular microscopy, pentacam and IOP measurement by applanation tonometer to evaluate endothelial cell count and IOP changes over 6 months. The main outcome measures were central corneal ECC, the percentage of corneal endothelial cell loss and IOP changes. Secondary outcome measures were UCVA, BCVA, manifest refraction, and complications.
Results: The mean pre-operative ECC in Group A was 3365±403 cell/mm2 ranged from 2830 to 3846 cell/mm2. In Group B, it was 3329±356 cell/mm2 ranged from 2901 to 3989. Post operative mean ECC in group A was 3183±344 cell/mm2 ranged from 2609 to 3686. In Group B, it was 3251±361cell/mm2 ranged from 2432 to 3621 at 6 month after surgery. The mean percentage endothelial cell loss in group A was 5.4% While in group B, it was 2.3% at the end of the follow up period (6 months). The mean pre-operative IOP in group A was 15.63 ±1.74 mmHg ranged from 12 to 18.2 mmHg, while in Group B, it was 15.53 ±1.98 mmHg ranged from 13 to 20 mmHg. Post operative mean IOP in group A was 14.95±1.01 mmHg ranged from 12.5 to 16.2 mmHg, while in Group B, it was 14.69±1.20 mmHg ranged from 12.6 to 16.7 mmHg at 6 month after surgery. The mean pre-operative UCVA in Group A was 0.03 ± 0.011 ranged from 0.01 to 0.04, while in Group B, it was 0.06 ± 0.023 ranged from 0.01 to 0.083. And by the end of the 6th month after surgery, the mean UCVA was 0.39 ± 0.10 in Group A, while it was 0.5 ± 0.27 in Group B. The mean pre-operative BCVA in Group A was 0.3 ±0.12 ranged from 0.16 to 0.7, while in Group B, it was0.4 ± 0.22 ranged from 0.25 to 1.00 the mean BCVA at 6 month after surgery was 0.49± 0.12 in Group A, while it was 0.62 ± 0.23 in Group B. The mean pre-operative spherical error (SE) in Group A was -15.3 ± 2.68 D ranged from -11D to -20D, while in Group B, it was -13.72 ± 3.97D ranged from -7D to -20.25D. by the end of the 6th month after surgery, the mean post operative SE was-1.02 ± 0.53 in Group A, while it was -1.18 ± 0.67 in Group B.
Conclusion: Our study revealed that pIOLs implantation (AC IOLs or PC IOLs) in high myopes had excellent results including; stability of refraction for high myopes, reversibility, high optical quality, potential gain in visual acuity, preservation of corneal architecture, asphericity and accommodation the comparison between the two types of pIOLs proved that the ICL was superior over the Artisan as regards the effect on corneal endothelium and postoperative AC inflammation, and they were equal as regards predictability, efficacy and the effect on IOP.