Prediction of Footplate Position after Implantable Collamer Lens Implantation Based on Iris and Ciliary Body Morphologies.

PURPOSE: To investigate the factors affecting footplate position and its influence on vault characteristics following implantable collamer lens (ICL) implantation. SETTING: Hunan Provincial People's Hospital, Changsha, China. DESIGN: Retrospective case series. METHODS: This study included 124 patients (124 eyes). Ultrasound biomicroscopy (UBM) was performed to assess the iris and ciliary body morphologies and observe the footplate position. Using multiple linear regression, the relationship between various ocular and ICL parameters and the vault as well as the factors affecting the footplate distance (FD) were analyzed. Based on the FD, three groups were formed: group 1 (<500 µm), group 2 (500-1000 µm), and group 3 (>1000 µm). The distribution of the vault range after surgery was observed for the three groups. RESULTS: Ciliary sulcus angle and FD significantly impacted the vault (adjusted R2=0.190, F=6.763, P<0.001), with FD being the most important factor influencing the vault (Beta=-0.383, P<0.001). Postoperative UBM revealed that the footplate was located at different positions in the posterior chamber, with the majority (52%) being located on the ciliary body. The average size of the four footplate orientations was 0.88±0.24 mm. Multiple linear regression analysis revealed that ciliary body thickness (CBT), iris curvature (IC), and ICL iris contact length (IRCL) significantly influenced the FD (adjusted R2=0.373, F=11.432, P<0.001). The vault range differed significantly among the three groups (X2=32.33, P<0.001). CONCLUSIONS: Different postoperative ICL footplate positions significantly affect the vault. CBT, IC, and IRCL can alter the position of the footplate from the expected position. This study provides reference for ICL size selection and vault prediction.

Effect of ciliary sulcus angle on the prediction of the vault for phakic implantable collamer lens in the KS formula.

PURPOSE: We aimed to explore the effects of the ciliary sulcus angle (CSA) on accurate prediction of the vault after phakic implantable collamer lens (EVO ICL Model V4c) using the KS formula. METHODS: Patients were classified according to the size of CSA: group A, narrow angle (CSA < 30°); group B, normal angle (CSA = 30-90°); and group C, wide angle (CSA > 90°). Further, differences between the actual vault dimensions at 3 months postoperatively and the preoperatively predicted vault dimensions in the three groups were analyzed. RESULTS: This study included 223 eyes of 223 individuals. In groups A-C, the difference in the preoperative vault dimensions of the three groups predicted with the KS formula was not statistically significant (P = 0.056). The actual vault dimensions at 3 months postoperatively were significantly different between the three groups (P < 0.001). Moreover, the difference between the actual and predicted vaults by the KS formula was statistically significant (P < 0.001). In the 3 months, after surgery, the percentages of patients with a low vault (< 250 µm) were 0%, 3%, and 29% in groups A, B, and C, respectively. Further, the percentages of patients with an ideal vault (250-750 µm) in the postoperative period were 66%, 84%, and 71% in groups A, B, and C, respectively. Finally, the percentages of patients with a high vault (> 750 µm) in the postoperative period were 34%, 13%, and 0% in groups A, B, and C, respectively. Notably, the distribution of the vault among the three groups was statistically significant (P < 0.001). CONCLUSION: The size of CSA significantly affects the predictiveness of the vault by the KS formula, with the most pronounced effect on the angles < 30° and > 90°. Therefore, CSA should be considered when selecting the lens size using the KS formula preoperatively. CLINICAL TRIAL REGISTRATION NUMBER: ChiCTR2200065501.

Comparison of the Accuracy of Seven Vault Prediction Formulae for Implantable Collamer Lens Implantation.

INTRODUCTION: This study aimed to compare the accuracy of seven implantable collamer lens (ICL) implantation vault prediction formulae. METHODS: We retrospectively analyzed 328 patients (328 eyes) who underwent ICL implantation and the prediction accuracy of seven formulae: NK, KS, WH, Luo, Zhu, Hun, and ZZ were compared. Moreover, the accuracy of the seven formulae for different ICL sizes was compared. The formulae were tested using mean absolute prediction error (MAE), median absolute prediction error (MedAE), prediction error (PE) percentages at ± 50 µm, ± 100 µm, ± 200 µm, and ± 300 µm, and Bland-Altman analysis. RESULTS: The PE of the seven formulae were statistically significant (P < 0.001). The KS (101.00 µm) and WH formulae (116.65 µm) had the smallest MedAE, followed by the Luo (123.62 µm), NK (141.50 µm), Hun (152.68 µm), ZZ (196.00 µm) and Zhu formula (225.98 µm). The highest percentage of PE in the range of ± 300µm was 94.3% and 93% for the KS and WH formulae, respectively. Among the different ICL size groupings, the KS formula predicted the smallest MedAE for 12.1 mm and 12.6 mm, whereas the Luo and WH formulae predicted the smallest MedAE for 13.2 mm and 13.7 mm, respectively. CONCLUSIONS: The KS and WH formulae provided better outcomes by predicting the vault with higher accuracy than of the NK, Hun, Luo, ZZ, and Zhu formulae. TRIAL REGISTRATION: ChiCTR2200065501.

Improvement in the ideal range of vault after implantable collamer lens implantation: a new vault prediction formula.

Background: To derive and validate a novel vault prediction formula to improve the predictability and safety of implantable collamer lens (ICL) implantation. Methods: Thirty-five patients (61 eyes) with previous posterior chamber intraocular lens implantation were included. Various parameters, such as horizontal-visible iris diameter (HVID), photopic pupil diameter (PPD), axial length (AL), white-to-white (WTW), anterior chamber width (ACW), angle-to-angle (ATA), crystalline lens rise (CLR), anterior chamber depth (ACD), horizontal sulcus-to-sulcus (HSTS), and ciliary sulcus angle (CSA) were measured. Vault was measured at 3 months after surgery using CASIA2 anterior segment optical coherence tomography. The formula was derived using multiple linear regression analysis and named as WH formula. It was validated in 65 patients (118 eyes) to determine the percentage of the ideal postoperative vault range and to compare the differences between the WH formula and the NK, KS, and STAAR formulas. Results: Final ICL size, ATA, CSA, and CLR were included in the prediction formula model (adjusted R2 = 0.67, p < 0.001). The achieved vault 1 month after the surgery was 556.19 µm ± 166.98 µm in the validation group, and the ideal vault range was 200-800 µm (92%). The difference between the achieved vault and that predicted using the WH formula was not statistically significant (p = 0.165), whereas the difference between the achieved vault and that predicted using the NK and KS formulas was statistically significant (p < 0.001 and p < 0.001, respectively). The 95% agreement limit range of the achieved vault and the vault predicted using the WH formula was narrower than those predicted using the NK and KS formulas (-295.20-258.82 µm). Conclusion: This study combined the results of optical coherence tomography and ultrasound biomicroscopy measurements of the anterior segment of the eye and incorporated ciliary sulcus morphology quantification into the prediction formula. The study derived a prediction formula for vault by combining ICL size, ATA, and CLR. The derived formula was found to be superior to the currently available formulas.

Optical and visual quality comparison of implantable collamer lens and femtosecond laser assisted laser in situ keratomileusis for high myopia correction.

AIM: To compare clinical outcomes and refractive stability of implantable collamer lens (ICL) implantation and femtosecond laser assisted laser in situ keratomileusis (FS-LASIK) for high myopia correction. METHODS: The Optical Quality Analysis System (OQAS) was used to evaluate clinical outcomes objectively after operation for high myopia correction. We compared the two procedures in terms of 1-year changes in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), safety index, efficacy index, spherical equivalent, modulation transfer function (MTF) cutoff frequency, strehl ratio (SR) and objective scatter index (OSI). RESULTS: At 1y postoperatively, the safety indices were 1.33±0.27 in ICL group, and 1.17±0.24 in FS-LASIK group. 39.58% in the ICL group and 27.59% in the FS-LASIK group gained CDVA in 2 lines or better than that in preoperative CDVA. The efficacy indices were 1.28±0.22 in ICL group, and 1.13±0.26 in FS-LASIK group. The changes of spherical equivalent from 1wk to 1y postoperatively was -0.12±0.37 D in ICL group, and -0.79±0.58 D in FS-LASIK group (P<0.05). Spherical equivalent within ±0.50 D was achieved in 97.92% in ICL group and 68.97% in FS-LASIK group. MTF cutoff frequency were higher with ICL as compared to FS-LASIK (P<0.05) at each postoperative follow-up stage; for postoperative 1mo later, SR was statistically significant difference between two groups (P<0.05); with no statistically significant difference in OSI between two groups (P>0.05) in postoperative 3mo later. CONCLUSION: ICL implantation and FS-LASIK procedures both provide good safety and predictability in high myopia correction. ICL implantation provides better clinical outcomes and refractive stability than FS-LASIK.

[Clinic observation of laser in situ keratomileusis for treatment of presbyopia with hypermetropia].

OBJECTIVE: To investigate the effects of Laser in situ keratomileusis (LASIK) for treatment of presbyopia with hypermetropia. METHODS: 32 presbyopia patients (64 eyes) with hypermetropia were treated by LASIK and follow-up 1 year. The preoperative sphere was +0.75 to +3.00 D and cylinder was 0.00 to +1.75 D. For distance vision correction, the target refraction was 0.00 to -0.50 D in the dominant eye. And for near vision, the target refraction was -1.50 to -2.50 D in the non-dominant eye. The measurement including refraction, uncorrected visual acuity (UCVA), near vision, Q factor of cornea and contrast sensitivity were recorded. RESULTS: At 1 year after surgery a total of 53.1% (17/32) of all patients had binocular distance UCVA of 20/25 or better along with J3 or better near, and along with J4 or better near was 87.5% (28/32). The postoperative corneal refractive power was significant higher than preoperative [3 mm: (44.12 +/- 1.38) D, 5 mm: (43.42 +/- 1.53) D] and Q factor became more negative. At 1 year 87.5% (28/32) and 100.0% (32/32) of the dominant eyes treated for distance had a manifest refractive spherical equivalent within +/- 0.50 and +/- 1.00 D of intended correction, respectively; of the non-dominant eyes treated for near, 56.2% (18/32) and 90.6% (29/32) had a manifest refractive spherical equivalent within +/- 0.50 and +/- 1.00 D of intended correction respectively. The difference of sensitivity was no statistically significant between preoperative and 6 months after surgery. There were 15.6% of the eyes had dry eye syndrome and 84.4% of the patients were satisfied with LASIK at 1 year after surgery. CONCLUSIONS: LASIK was a effect surgery for treatment of presbyopia with hypermetropia.

[Effects of matrix metalloproteinase-3, osteopontin, and tissue inhibitor of metalloproteinase-1 in the formation of cataract].

OBJECTIVE: To investigate the expression and significance of matrix metalloproteinase-3 (MMP-3), osteopontin (OPN) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in human lens epithelial cells (LECs) of cataract. METHODS: The MMP-3, OPN, and TIMP-1 expressions in LECs of anterior subcapsular cataract (31 cases), nuclear cataract (28 cases) and normal lens (12 cases) were detected by immunohistochemistry, respectively. RESULTS: The MMP-3 expression in anterior subcapsular cataract was significantly higher than that in nuclear cataract and normal lens (chi2=31.49, 34.479; P=0.000); but there was no statistic significance between nuclear cataract and normal lens (chi2=2.449, P=0.118). The OPN expression in anterior subcapsular cataract was also significantly higher than that in nuclear cataract and normal lens (chi2=29.450, 15.889; P=0.000). There was no significant difference in the TIMP-1 expression among the 3 groups (P>0.05). Positive correlation was found between MMP-3 and OPN in LECs of anterior subcapsular cataract (r=0.381, P=0.035). But no significant correlation was found among MMP-3, OPN, and TIMP-1 (r=0.121, -0.289; P=0.516, 0.114). CONCLUSION: Increased expression of MMP-3 and OPN and the expression imbalance between MMP-3 and TIMP-1 may play a critical role in the pathogenesis of anterior subcapsular cataract.