Purpose: To determine patient preoperative anatomical features and the parameters of implantable collamer lenses (ICLs) relevant in explaining vault variability. Setting: Ophthalmology Clinic Vista Sánchez Trancón, Badajoz, Spain. Design: Retrospective case series. Methods: This study comprised 360 eyes of 360 patients implanted with myopic or toric ICLs. Pentacam imaging was used for assessing white-to-white (WTW) diameter, central keratometry, and central corneal thickness. Anterior-segment optical coherence tomography was used to measure the horizontal anterior chamber angle distance (ATA), internal anterior chamber (ACQ), crystalline lens rise (CLR), anterior chamber angle (ACA), and vault. The sample was divided according to the implanted lens size (12.6 mm, 13.2 mm, and 13.7 mm). Vault predictors were identified from the variables above using multivariate regression analysis. Results: The groups showed significant statistical differences for WTW, ATA, ACQ, ACA, and vault (P < .007 for all). In general, bigger lenses were implanted in eyes with larger transverse sizes (WTW and ATA) and deeper ACQ. Also, larger ICL diameters were associated with higher vaults. Multivariate regression analysis identified the lens size (13.2 mm as reference; 12.6 mm: β [standardized coefficients] = −0.33; 13.7 mm: β = 0.42), ATA (β = −0.42), and CLR (β = −0.25), ICL spherical equivalent (β = −0.22) and patient age (β = −0.12) as predictors of the vault size (adjusted-R 2 = 0.34 P < .001). Conclusions: The multivariate model explained 34% of vault variability. The predictors indicated the presence of different mechanisms regulating the vault. These involved the difference between the transverse size of the eye and the ICL, the crystalline lens protrusion, and the ICL properties, such as power and size.

Background To identify biometric and implantable collamer lens (ICL)-related risk factors associated with sub-optimal postoperative vault in eyes implanted with phakic ICL. Methods This study reports a retrospective case series of the first operated eye in 360 patients implanted with myopic spherical or toric ICL. Preoperatively, white-to-white (WTW), central keratometry (Kc) and central corneal thickness (CCT) were measured using the Pentacam. Anterior-segment optical coherence tomography (AS-OCT, Visante) was applied preoperatively for measuring the horizontal anterior-chamber angle-to-angle distance (ATA), internal anterior chamber depth (ACD), crystalline lens rise (CLR), anterior-chamber angle (ACA) and postoperatively the vault. Eyes were divided into three vault groups: low (LVG: ≤ 250 μm), optimal (OVG: > 250 and < 1000 μm) and high (HVG: ≥ 1000 μm). Multinomial logistic regression (MLR) was used to find the sub-optimal vault predictors. Results MLR showed that CLR, ICL size minus the ATA (ICL size-ATA), age, ICL spherical equivalent (ICLSE) and ICL size as contributing factors for sub-optimal vaults (pseudo-R2 = 0.40). Increased CLR (OR: 1.01, CI: 1.00–1.01) and less myopic ICLSE (OR: 1.22, CI: 1.07–1.40) were risk factors for low vaults. Larger ICL size-ATA (OR: 41.29, CI: 10.57–161.22) and the 13.7 mm ICL (OR: 7.08, CI: 3.16–15.89) were risk factors for high vaults, whereas less myopic ICLSE (OR: 0.85, CI: 0.76–0.95) and older age (OR: 0.92, CI: 0.88–0.98) were protective factors. Conclusion High CLR and low ICLSE were the major risk factors in eyes presenting low vaults. In the opposite direction, ICL size-ATA was the major contributor for high vaults. This relationship was more critical in higher myopic ICLSE, younger eyes and when 13.7 mm ICL were used. The findings show that factors influencing the vault have differentiated weight of influence depending on the type of vault (low, optimal or high).

Purpose The distance between an implantable collamer lens (ICL) and the crystalline lens, namely vault, is a space regulated by the interaction of the ICL and the anatomical structures of the eye. This study analysed the differences in vault size between fellow eyes with similar anterior segment biometry. Patients and Methods A retrospective case series analysed 109 cases of patients bilaterally implanted with EVO-V4c. Patients were analysed pre- and postoperatively using anterior segment optical coherence tomography. The range of vault inter-eye differences was defined as the 95% confidence interval of the differences. Bivariate correlation was applied to seek for associations between vault inter-eye differences with biometric and lens parameters (angle-to-angle, anterior chamber depth, crystalline lens rise, central corneal thickness, central keratometry, ICL spherical equivalent, horizontal compression, postoperative pupil diameter and vault). Results Mean vault inter-eye differences were similar between fellow eyes (26.0 ± 122.5 µm). The 95% confidence interval range of the differences was ±240.1 µm, nearly 50% of the cases presented vault inter-eye differences higher than 100 µm. The vault of the first operated eye explained 81% of the variance in the second eye vault. Vault inter-eye differences were positively correlated with the level of horizontal compression and with vault magnitude. Conclusion Vaults measured in fellow eyes may present considerable differences, which can reach 25% of the common vault range. This reflects some degree of baseline variability in the vault. Clinically, these differences assume special relevance in cases where low or high vaults are expected.

Purpose To determine the influence of implantable collamer lenses (ICL) geometry, i.e. spherical and toric on the vault, and report the refractive and visual outcomes of patients bilaterally implanted with the two ICL geometries. Methods This retrospective case series analysed 41 patients implanted with a spherical ICL (sICL) in one eye and an equal sized toric ICL (tICL) in the fellow eye. The anatomical and ICL-related parameters were assessed using anterior-segment optical coherence tomography (AS-OCT Visante, Zeiss Meditec AG) and optical tomography (Pentacam, OCULUS). The influence of the anatomical and ICL-related parameters on the vault was determined using generalised estimating equations (GEE) to incorporate inter-eye correlations. Results Postoperative spherical equivalent was within ± 0.50D in 66% and 83% of the eyes, respectively implanted with sICL and tICL. The efficacy index in the sICL group was 1.06 and 1.14 in the tICL group. The mean inter-eye vault difference was -1.46 µm, anatomical and ICL-related parameters showed similar associations with the vault for sICL and tICL. The GEE identified the ICL size minus the anterior chamber width, the ICL spherical power and ICL central thickness as significant factors influencing the vault. Conclusions Spherical and toric ICL showed good efficacy for the correction of myopia and astigmatism. Patients implanted bilaterally with sICL and tICL tend to present similar vaults. The vault produced by both types of ICL was mainly regulated by the oversizing of the ICL. This suggests that the ICL geometry (spherical vs toric) is a factor with limited influence on the vault, thus the sizing method of a sICL and tICL should be similar.

Posterior chamber phakic intraocular lens implantation is a refractive technique for the correction of myopia. This study aimed to identify those factors contributing to variability in postoperative refraction. Methods: This retrospective study evaluated 73 eyes (one eye per patient) implanted with myopic implantable collamer lenses (ICL). Eyes were divided into two groups, the low myopic group (LMG) (ICL > −9.5 DS) and the high myopic group (HMG) (ICL ≤ −9.5 DS), to compare the predictability, efficacy index, and postoperative refraction between groups. The association of postoperative refraction with anatomical, demographic, and optical features was assessed through correlation analysis and investigated using ray-tracing. Results: Postoperative refraction at 3 months for the whole group was close to emmetropia at −0.02 ± 0.37 DS, the LMG tended toward myopia and the HMG, toward hyperopia. The results showed that 65% and 54% of the eyes had postoperative refraction of within ±0.25 DS, respectively, in the LMG and HMG, and in both groups, 100% were within ±1.00 DS. ICL implantation had a higher efficacy index in the HMG (1.13 ± 0.15) than in the LMG (1.04 ± 0.15). Postoperative refraction was positively associated with the vault (R = 0.408) and negatively correlated with ICL power (R = −0.382). Conclusion: The predictability and effectiveness of ICL implantation is high in a wide range of myopias. Considering the expected vault and including accurate vertex measurements would contribute to improving the predictability of the results.

Purpose To evaluate the influence of corneal tomographic and biomechanical indexes on the refractive technique indication. Methods A total of 251 eyes from 251 patients interested in refractive surgery were enrolled in this cross-sectional and multicenter study. Previous to the surgeon decision, a preoperative protocol was performed by refractive optometrists, containing four sections: refraction, biometry, corneal tomography and biomechanics. The refractive surgeons made a first decision based only on refraction, biometric and tomographic information. Biomechanical indexes were revealed, and refractive surgeons made a second indication. Additionally, for Laser-Assisted in-situ Keratomileusis cases, the percent tissue altered were calculated. Possible indications were no refractive surgery, photorefractive keratectomy, Laser-Assisted in-situ Keratomileusis or intraocular Collamer lens. Results After the first surgery indication, the distribution was photorefractive keratectomy (47.4%), Laser-Assisted in-situ Keratomileusis (48.2%) while intraocular Collamer lens achieved 2.8%. This proportion changed significantly after the second indication regarding corneal biomechanics and photorefractive keratectomy and Laser-Assisted in-situ Keratomileusis decreased by 24% while intraocular Collamer lens increased 19%. A total of 69 eyes changed the indication (27.5%) and 182 eyes (72.5%) remained unchanged. All indications changes were from photorefractive keratectomy or Laser-Assisted in-situ Keratomileusis to intraocular Collamer lens or no surgery. Indication changes to intraocular Collamer lens were observed in 49 eyes (71%). Tomographic, biomechanical indexes, ablation depth and percent tissue altered achieved statistically significant differences between eyes without and with indication changes (all, P < .01). Conclusion New corneal biomechanical indexes could change the indication decision regarding biometric and tomographic data alone. Intraocular Collamer len was the preferred indication for eyes at risk of ectasia or with subclinical keratoconus due to corneal biomechanical parameters.

To determine the predictors of the postoperative horizontal trabecular iris angle (TIA 750 ) after phakic posterior chamber implantable intraocular lens (IOL) surgery.