The results of our study showed that anterior chamber parameters including ICA, ACD, TISA 500, TISA 750, AOD 500, AOD 750, and the pupil diameter under different light conditions were reduced significantly after the implantation of the Eyecryl pIOL. The change in the mean K and IOP was not statistically significant (p = 0.07 and p = 0.23, respectively).
We found that ICA decreased by 38.7% and 38.5% at 1 and 3 months after surgery, respectively. The mean ICA dropped from 49.97° ± 6.33 before surgery to 30.75° ± 5.86 and 30.79° ± 5.74 at 1 and 3 months after surgery, respectively. Similarly, decrease of 31.6% and 31.5% in ICA after ICL implantation was found by Elmohamady et al. at 1 and 3 months [6]. Also, Chung et al. evaluated ICA using UBM (ultrasound bio-microscopy) and found a reduction of 31.7% after 1 month [10].
In our study, the mean ACD was reduced from 3.23 ± 0.22 mm preoperatively to 2.55 ± 0.34 mm and 2.46 ± 0.28 mm at 1 and 3 months postoperatively, respectively. The rate of reduction was 21% and 23.8% at 1 and 3 months postoperatively, respectively. Our results were consistent with the study by Ju et al. [10]. They reported a reduction in the mean ACD from 3.28 ± 0.14 mm preoperatively to 2.45 ± 0.22 mm at 3 months postoperatively. Similar results were also found by Elmohamady et al. as 3.59 ± 0.17 mm preoperatively and 2.96 ± 0.25 mm at 3 months postoperatively [6].
In our study, the mean vault was measured as 551.75 ± 203.71 µm and 580.55 ± 182.44 µm at 1 and 3 months after surgery, respectively. Similarly, the mean vault for ICL in the study by Elmohamady et al. was found to be 556 ± 33 µm and 431 ± 56 µm at 1 and 3 months after surgery, respectively [6]. Also, similar vault values were reported for ICL in different studies [10, 11].
Our study showed that the mean pupil diameter under scotopic, mesopic, and photopic illumination conditions was reduced insignificantly by 1 month but significantly by 3 months after surgery. Although Elmohamady et al. found a statistically insignificant reduction in pupil diameter after ICL implantation, a statistically significant reduction in pupil diameter was shown in other studies [6, 15, 16]. Moreover, Zhu et al. reported a significant reduction in pupil diameter under mesopic and photopic illumination conditions and no change under scotopic illumination condition [17]. Similar to Zhu et al., a reduction in pupil diameter under mesopic and photopic illumination conditions after the Eyecryl pIOL was found to be statistically more significant than a reduction under scotopic illumination condition in our study.
The miotic effect of pIOL implantation provides benefits for patients, as it can reduce aberrations that may occur after surgery. On the other hand, the miotic effect may decrease aqueous humor circulation in eyes with a pIOL that has no central hole. Subsequently, the decreased circulation of aqueous humor may result in increased IOP after surgery. In our study, we observed neither clinically decreased circulation of aqueous humor nor increased IOP after surgery.
In the current study, we performed Spearman correlation analysis to assess whether there was a correlation between anterior segment parameters and pupil diameter; however, we did not detect any significant correlation. Inconsistent with our findings, Elmohamady et al. stated a significant positive correlation between the ICL vault and pupil diameter at 1 month postoperatively (r = 0.9429, p < 0.001) [6]. In line with our results, Li et al. had not found also a significant correlation between the ICL vault and pupil diameter after surgery [15].
The current study has several limitations including retrospective design and relatively short follow-up. Moreover, regarding the change in the pupil, only pupil size was evaluated in the current study; however, pupil contraction amplitude and velocity in light reflexes were not assessed.
In conclusion, we demonstrated that anterior segment parameters including ACD, ICA and angle opening metrics declined significantly by 1 month and changed slightly by 3 months after surgery; however, the mean pupil size decreased insignificantly by 1 month and continued to decrease significantly by 3 months after surgery. The effects of the Eyecryl pIOL on anterior segment parameters and pupil size was similar to that of the ICL demonstrated in previous studies.