The Distribution of Crystalline Lens Rise in High Myopia Population and Its Influence on Vault After Implanting Intraocular Collamer Lens.

INTRODUCTION: As a result of the insufficient ocular anatomical parameters used to customize implantable collamer lens (ICL), many patients still cannot achieve a suitable vault after ICL implantation surgery. This study analyzed the characteristics of a new anatomical parameter crystalline lens rise (CLR) in a population with high myopia and explored the influence of CLR on the vault after ICL implantation. METHODS: Patients (298 eyes) with high myopia who underwent ICL implantation were enrolled to study CLR characteristics. Postoperatively, patients (159 eyes) were divided into five groups according to the value of CLR (A, CLR ≤ - 150; B, - 150 < CLR ≤ 0; C, 0 < CLR < 150; D, 150 ≤ CLR < 300; E, CLR ≥ 300 µm), and to investigate the correlation between CLR and vault. RESULTS: In the 298 eyes, the CLR had a normal distribution (P = 0.35) and the mean CLR was 67.93 ± 150.66 µm. Ninety-nine eyes (33.22%) had a CLR ≤ 0 µm, of which 20 eyes (6.71%) had a CLR ≤ - 150 µm; 199 eyes (66.78%) had a CLR > 0 µm, of which 20 eyes (6.71%) had a CLR ≥ 300 µm. In 159 eyes, the CLR was negatively correlated with the vault at 1 day (R = - 0.497, P < 0.001), 3 months (R = - 0.505, P < 0.001), and 6 months (R = - 0.505, P < 0.001) postoperatively. At 6 months, the vault of group A was statistically significantly different compared to groups B-E (all P < 0.05), and that of group E was statistically significantly different compared to groups A-D (all P < 0.001). The remaining groups did not show statistically significant differences (all P > 0.05). CONCLUSION: The CLR had a normal distribution in the high myopia population, and 13.42% of the CLR values were extreme (CLR ≤ - 150 µm or CLR ≥ 300 µm). A larger ICL diameter than that recommended by the manufacturer should be considered when the CLR is ≥ 300 µm and a smaller ICL diameter should be considered when the CLR is ≤ - 150 µm.

Refractive outcome in combined phacovitrectomy: Anterior segment changes and corrective factor for IOL power calculation improvement.

PURPOSE: To analyze differences in refractive outcome Δ (difference between postoperative and expected refractive error) and in anterior segment changes between cataract surgery patients and combined phacovitrectomy patients. We also aimed to provide a corrective formula allowing to minimise the refractive outcome Δ in combined surgery patients. METHODS: Candidates for phacoemulsification and combined phacovitrectomy (respectively PHACO and COMBINED groups) were prospectively enrolled in two specialised centres. Patients underwent best corrected visual acuity (BCVA) assessment, ultra-high speed anterior segment optical coherence tomography (OCT), gonioscopy, retinal OCT, slit lamp examination and biometry at baseline, 6 weeks postoperatively and 3 months postoperatively. RESULTS: No differences in refractive Δ, refractive error and anterior segment parameters were noted between PHACO and COMBINED group (109 and 110 patients respectively) at 6 weeks. At 3 months, COMBINED group showed a spherical equivalent of -0.29 ± 0.10 D versus -0.03 ± 0.15 D in PHACO group (p = 0.023). COMBINED group showed a significantly higher Crystalline Lens Rise (CLR), angle-to-angle (ATA) and anterior chamber width (ACW) and a significantly lower anterior chamber depth (ACD) and refractive Δ with all 4 considered formulas at 3 months. For IOL power lower than 15, a hyperopic shift was observed instead. CONCLUSIONS: Anterior segment OCT suggests anterior displacement of the effective lens position in patients undergoing phacovitrectomy. A corrective formula can be applied to IOL power calculation to minimize undesired refractive error.

Prediction of vault after implantable collamer lens implantation and its research progress / 国际眼科杂志(Guoji Yanke Zazhi)

Myopia is considered to be a disease occurred under the influence of genetic and environmental factors, and it can only be restored by corrective surgeries. The current surgical methods include laser surgeries and phakic intraocular lens(PIOL)implantation, and PIOL has the advantages of wide range of correction, repeatable procession and small damage to corneal tissue. Furthermore, good visual acuity can be achieved after implantation of intraocular lens. Implantable collamer lens(ICL)is the most common surgical method in this group. The vertical distance between the highest point of the posterior central surface of the implanted lens and the anterior surface of the crystalline lens is called vault. It will cause serious complications if the vault turns out to be abnormal. Up to now, there is no optimal prediction method. This research focuses on vault, discusses the ideal range of postoperative vault, the safety and effectiveness of this surgery, and analyzes the existing prediction methods to provide directions for future clinical research.

Lens-vault analysis and its correlation with other biometric parameters using swept-source OCT

Purpose: To measure lens vault (LV) and to assess its correlation with various ocular parameters in healthy eyes, using for all measurements the same high-resolution swept-source optical coherence tomographer (SS-OCT).Methods: We prospectively recruited 67 Caucasian healthy patients whose mean age was 41.9 ± 12.4 years; only their right eye was included in the study. Data were all recorded with the ANTERION SS-OCT and comprised, for each patient, 5 consecutive measurements of LV, anterior chamber depth (ACD), lens thickness (LT), axial length (AL), white-to-white (WTW) distance, central corneal thickness (CCT), anterior chamber volume (ACV) and spur-to-spur (STS) distance.Results: Mean LV was 0.26 ± 0.23 mm (ranging from -0.24 to 0.78 mm). Data analysis revealed a statistically significant negative correlation between LV and ACD (R=-0.80, p < 0.001), AL (R = -0.36, p = 0.002), and ACV (R = -0.68, p < 0.001), and a positive correlation between LV and LT (R = 0.67, p < 0.001), and age (R = 0.53, p < 0.001). In contrast, no statistically significant correlation was found between LV and WTW (R=-0.17, p = 0.15), CCT (R = 0.11, p = 0.36) or STS (R=-0.10, p = 0.41).Conclusions: Taking into account our findings about intra-parameter correlation levels, we believe that LV should be measured and analyzed together with other ocular parameters in clinical routine practice both for diagnosis and for some refractive surgeries. (AU)

Lens-vault analysis and its correlation with other biometric parameters using swept-source OCT.

PURPOSE: To measure lens vault (LV) and to assess its correlation with various ocular parameters in healthy eyes, using for all measurements the same high-resolution swept-source optical coherence tomographer (SS-OCT). METHODS: We prospectively recruited 67 Caucasian healthy patients whose mean age was 41.9 ±â€¯12.4 years; only their right eye was included in the study. Data were all recorded with the ANTERION SS-OCT and comprised, for each patient, 5 consecutive measurements of LV, anterior chamber depth (ACD), lens thickness (LT), axial length (AL), white-to-white (WTW) distance, central corneal thickness (CCT), anterior chamber volume (ACV) and spur-to-spur (STS) distance. RESULTS: Mean LV was 0.26 ± 0.23 mm (ranging from -0.24 to 0.78 mm). Data analysis revealed a statistically significant negative correlation between LV and ACD (R=-0.80, p < 0.001), AL (R = -0.36, p = 0.002), and ACV (R = -0.68, p < 0.001), and a positive correlation between LV and LT (R = 0.67, p < 0.001), and age (R = 0.53, p < 0.001). In contrast, no statistically significant correlation was found between LV and WTW (R=-0.17, p = 0.15), CCT (R = 0.11, p = 0.36) or STS (R=-0.10, p = 0.41). CONCLUSIONS: Taking into account our findings about intra-parameter correlation levels, we believe that LV should be measured and analyzed together with other ocular parameters in clinical routine practice both for diagnosis and for some refractive surgeries.

Effect of crystalline lens rise on the vault after implantation of phakic posterior chamber implantable collamer lens / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To investigate the relationship between crystalline lens rise(CLR)measured by anterior segment-optical coherence tomography(AS-OCT)and parameters of the anterior segment. And also measure the effects of CLR on the vault after phakic posterior chamber implantable collamer lens(PPC-ICL)implantation.<p>METHODS:The study included 80 eyes of 40 patients who underwent PPC-ICL implantation at the Department of Ophthalmology, the Second Affiliated Hospital of Anhui Medical University, from July 2017 to July 2018, to measure the sulcus-to-sulcus(hSTS)distance of the eyes using a Compact Touch STS ultrasound biomicroscope and lens curvature(LC), Pentacam was used to measure horizontal-white-to-white(hWTW), anterior chamber depth(ACD)and the vault one year after the operation. Moreover, AS-OCT was used to measure the CLR and horizontal iridocorneal angle-to-iridocorneal angle diameter(ATA).<p>RESULTS:CLR was negatively correlated with ACD(<i>r</i>= -0.706, <i>P</i><0.01)and vault one year after the operation(<i>r</i>= -0.509, <i>P</i><0.01); however, it was positively correlated with LC(<i>r</i>=0.667, <i>P</i><0.01). There was no correlation between CLR and hWTW(<i>r</i>=0.123, <i>P</i>=0.275), ATA(<i>r</i>=0.208, <i>P</i>=0.065)and hSTS(<i>r</i>=0.147, <i>P</i>=0.194). One year after the operation, there was a positive correlation between the vault and ACD(<i>r</i>=0.680, <i>P</i><0.01).<p>CONCLUSION:CLR has obvious correlation with ACD and LC, arch height after PPC-ICL and has a specific effect on the prediction of the vault after PPC-ICL implantation.

Effect of Tropicamide on crystalline Lens rise in low-to-moderate myopic eyes.

BACKGROUND: Cycloplegics have been reported to induce changes in the lens thickness. However, the studies of correlation between cycloplegia and the lens position are limited. This study aims to investigate changes in crystalline lens rise (CLR) and other anterior segment parameters after inducing cycloplegia with tropicamide. METHODS: In this consecutive case study, 39 children (20 boys and 19 girls; mean age, 9.51 ± 1.75 years, mean spherical equivalence [SE], - 1.9 ± 1.5 D) with low-to moderate myopia were examined using CASIA 2 both before and after 30 min of administering 5-cycles (each 5 min apart) of 0.5% tropicamide. Measurements included CLR, crystalline lens thickness (CLT), mean radius of curvature of the anterior/posterior surface of the lens (Rf_ave/Rb_ave), anterior chamber depth (ACD), anterior chamber width (ACW), and central corneal thickness (CCT). Correlations of CLT and CLR with ACD, SE, and age were assessed respectively. RESULTS: CLT and CLR decreased significantly after cycloplegia (p < 0.001 and p < 0.001, respectively); whereas CCT, ACD, and Rf_ave increased (p = 0.008, p < 0.001, p < 0.001, respectively). A positive correlation was found between CLR and SE (r = 0.565, p < 0.001). However, a negative correlation between ACD and CLR was found before and after cycloplegia (r = - 0.430, p = 0.006; r = - 0.342, p = 0.035, respectively). CONCLUSIONS: The crystalline lens appeared thinner and moved backward after cycloplegia. ACD increased mainly due to the backward movement of the crystalline lens. These results aid in elucidating the impact of crystalline lens changes during the process of accommodation.

Effect of Preoperative Crystalline Lens Rise on Vaulting after Implantable Collamer Lens Implantation

PURPOSE: To evaluate the parameters affecting vaulting and correlation between preoperative crystalline lens rise and vaulting after implantable collamer lense (ICL) implantation. METHODS: A total of 53 eyes of 34 patients who underwent ICL implantation were examined retrospectively. White-to-white (WTW) and anterior chamber depth (ACD) were obtained from scanning topography (ORB scan) before surgery. Preoperative crystalline lens rise (CLR) and vaulting at 6 months after ICL implantation were measured using anterior segment optic coherence tomography (AS-OCT). Multiple regression analysis was performed to evaluate the factors affecting central vaulting. RESULTS: The mean preoperative crystalline lens rise was -120 +/- 219 microm, and mean central vaulting 6 months after surgery was 544 +/- 175 microm. Preoperative SE, WTW, ACD, and CLR were significantly correlated with vaulting at 6 months after surgery. With the use of meaningful variables, multiple regression analysis showed that CLR, WTW, ACD and SE, in that order of influence, had significant effects on vaulting and the multiple regression equation was obtained as follows: Vaulting (microm) = (160.913 x ACD (mm)) + (170.134 x WTW (mm)) + (-0.338 x CLR (microm)) + (-23.783 x SE (D)) - 2250.184. CONCLUSIONS: CLR had a stronger influence on vaulting after ICL implantation than the previously proven parameters: WTW, ACD, and SE. In addition to WTW, ACD and SE, CLR should also be considered a new criterion for estimating vaulting after ICL implantation.