Higher-order aberration changes after Implantable Collamer Lens implantation for myopia

Visual outcomes of combined use of implantable collamer lens implantation and laser corneal visual correction for myopia over -18.00 diopters

PURPOSE

To explore visual outcomes in patients with extreme myopia receiving an implantable collamer lens (ICL) at -18.00 diopters (D), with central port, followed by bioptics by laser vision correction (laser in situ keratomileusis [LASIK] or photorefractive keratectomy [PRK]) to address residual myopia or myopic astigmatism.

SETTING

Clínica Baviera (Aier Eye Hospital Group), Bilbao, Spain.

DESIGN

Retrospective analysis of cases.

METHODS

The study assessed uncorrected distance visual acuity, corrected distance visual acuity (CDVA), predictability, safety, efficacy, and patient satisfaction after implantation of the ICL and bioptics. The model implanted was V4c and EVO, with a correction of -18.00 D. Bioptics were performed at least 3 months after implantation, and patients were followed up for at least 3 months after LASIK or PRK.

RESULTS

The analysis included 125 eyes from 90 patients. Of these, 51.2% underwent LASIK and 48.8% PRK. Mean time from implantation to bioptics was 5.9 ± 9.4 months. Patients were followed up for a mean of 40.2 ± 37.9 months after bioptics. Median manifest refractive spherical equivalent was -2.89 D before bioptics and -0.49 D after. Median CDVA was 0.18 logMAR before bioptics and 0.17 after. The mean safety and efficacy indices were 2.22 ± 1.88 and 2.06 ± 1.85, respectively.

CONCLUSIONS

Visual outcomes and safety indices after ICL implantation and subsequent LASIK or PRK in patients with extreme myopia are excellent.

Comparing the Early Changes in Classified Higher-Order Aberrations Before and After Non-Toric and Toric Implantable Collamer Lens V4c Implantation

PURPOSE

This study aimed to compare early changes in classified higher-order aberrations (HOAs) pre- and postsurgery in patients who received nontoric versus toric implantable collamer lenses (ICL; ICL Model V4c; STAAR Surgical, Monrovia, CA, USA).

METHODS

This prospective study included 124 eyes of 64 patients: 49 eyes were treated using a nontoric implantable collamer lens (ICL), and 75 eyes were treated using a toric implantable collamer lenses (TICL). Refractive parameters and ocular aberrations were examined before and 1 month after surgery.

RESULTS

At one month, the safety indices were 1.24 ± 0.17 in the ICL group and 1.20 ± 0.25 in the TICL group (p = 0.39). The efficacy indices were 1.07 ± 0.17 in the ICL group and 1.15 ± 0.26 in the TICL group (p = 0.02). The root mean square (RMS) values of whole-eye total HOAs, trefoil, corneal total HOAs, spherical aberration, and intraocular spherical aberration significantly increased postoperatively in both groups. The RMS of intraocular total HOAs in the TICL group significantly increased 1 month postoperatively. No statistically significant differences were observed in HOA changes between the ICL and TICL groups.

CONCLUSIONS

The dominant increases in short-term aberrations after ICL and TICL V4c implantation were in corneal trefoil and intraocular spherical aberrations, which were related to the corneal incision and implanted lens. The HOA changes post-surgery were not statistically different between the two lens types.

Differences in ocular high order aberrations before and after small incision lenticule extraction for correction of myopia: a systematic review and meta-analysis

Objective

To examine the causes and factors that lead to high order aberration (HOA) during the treatment of myopia using small incision lenticule extraction (SMILE), as well as the differences between SMILE and other corneal refractive surgeries through a systematic review and meta-analysis.

Methods

A systematic search was conducted from January 2015 to February 2023 in Pubmed, Embase, Web of Science, and Google Scholar databases to gather relevant studies on SMILE and HOA. Studies meeting specific criteria were chosen, and clinical data was retrieved for analysis.

Results

This meta-analysis resulted in the inclusion of 19 studies involving 1,503 eyes. Pooled results showed significant induction of total HOA (tHOA, d = -0.21, p < 0.001), spherical aberration (SA, d = -0.11, p < 0.001) and coma aberration (CA, d = -0.18, p < 0.001) after SMILE compared to pre-SMILE, while no significant change in trefoil aberration (TA) was observed (d = -0.00, p = 0.91). There was a significantly lower induction of tHOA after SMILE compared to femtosecond laser-assisted in situ keratomileusis (FS-LASIK, d = 0.04, p < 0.001), and no significant difference was observed compared to wavefront aberration-guided (WFG) refractive surgery (d = 0.00, p = 0.75). There was also a significant association between different levels of myopia and astigmatism, duration of follow-up, lenticule thickness, and preoperative central corneal thickness (CCT) on the induction of tHOA after SMILE (p < 0.05), while the higher preoperative myopia group (sphere > -5D), lower preoperative astigmatism group (cylinder ≤ -1D), larger lenticule thickness group (lenticule thickness > 100 μm), shorter follow-up group (follow-up 1 month postoperatively) and the thicker CCT group (CCT > 550 μm) brought a significant induction of tHOA compared to the opposite comparison group (p < 0.001).

Conclusion

While SMILE can induce HOA significantly, it induces less HOA than FS-LASIK. Postoperative HOA following SMILE can be affected by factors such as myopia, astigmatism, lenticule thickness, CCT, and duration of follow-up. Future research should continue to explore techniques to decrease the induction of HOA by using this methodology.

Systematic review registration

https://www.crd.york.ac.uk/prospero/.

The comparison of corneal higher-order aberration and surgically induced astigmatism between the clear corneal incision and the limbus tunnel incision of posterior chamber implantable collamer lens implantation

BACKGROUND

This study aimed to compare the corneal high-order aberrations and surgically induced astigmatism between the clear corneal incision and limbus tunnel incision for posterior chamber implantable collamer lens (ICL/TICL) implantation.

METHODS

A total of 127 eyes from 73 myopic patients underwent ICL V4c implantation, with 70 eyes receiving clear corneal incisions and 57 eyes receiving limbus tunnel incisions. The anterior and back corneal surfaces were measured and the Root Mean Square of all activated aberrations (TRMS) was calculated, including higher-order aberration (HOA RMS), spherical aberration Z40, coma coefficients (Coma RMS) Z3-1 Z31, and surgically induced astigmatism (SIA). The measurements were taken preoperatively and postoperatively at 1 day, 1 week, and 1, 3, and 6 months. In this study, the corneal higher-order aberration was estimated as the Zernike coefficient calculated up to 5th order. The measurements were taken at a maximum diameter of 6.5 mm using Pentacam.

RESULTS

One week after the operation, the corneal back Z31 of the clear corneal incision group was 0.06 ± 0.06, while the limbus tunnel incision group showed a measurement of 0.05 ± 0.06 (p = 0.031). The corneal back Z40 of the clear corneal incision group was -0.02 ± 0.25, compared to -0.04 ± 0.21 in the limbus tunnel incision group (p = 0.01). One month after the operation, the corneal back SIA of the clear corneal incision group was 0.11 ± 0.11, compared to 0.08 ± 0.11of the limbus tunnel incision group (p = 0.013), the corneal total SIA of the clear corneal incision group was 0.33 ± 0.30, compared to 0.15 ± 0.16 in the limbus tunnel incision group (p = 0.004); the clear corneal incision group exhibited higher levels of back astigmatism and total SIA than the limbus tunnel incision in the post-operation one month period. During the 6- month post-operative follow-up period, no significant difference in Z31, Z40, and other HOA RMS data was observed between the two groups. The total SIA of the corneal incision group and the limbus tunnel incision group were 0.24 ± 0.14 and 0.33 ± 0.32, respectively (p = 0.393), showing no significant difference between the two groups 6 months after the operation.

CONCLUSION

Our data showed no significant difference in the high-order aberration and SIA between clear corneal incision and limbus tunnel incision up to 6 months after ICL-V4c implantation.

The Efficacy of Paired Opposite Clear Corneal Incisions Correcting Preexisting Low-to-Moderate Astigmatism in Implantable Collamer Lens Surgery

PURPOSE

To evaluate the efficacy of paired opposite clear corneal incisions (OCCIs) in Implantable Collamer Lens (ICL; STAAR Surgical) implantation surgery for correcting preexisting low-to-moderate astigmatism and observe their influence on corneal aberration.

METHODS

This prospective controlled randomized study included 123 eyes: 73 eyes in the ICL surgery group (control group) and 50 eyes in the ICL combined with OCCI group (OCCI group). All patients had corneal astigmatism between 0.50 and 3.00 D. Parameters considered included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, keratometry, slit-lamp biomicroscopy, indirect ophthalmoscopy, corneal topography, and higher order aberrations (HOAs). The Alpins method was used to analyze the correction of astigmatism. The follow-up period lasted for 12 months.

RESULTS

Both groups showed a statistically significant improvement in mean UDVA and CDVA after surgery. At 1 and 12 months, the OCCI group had statistically better UDVA than the control group (P = .021 and .01). The OCCI group showed a significant reduction in mean refractive astigmatism from -0.835 ± 0.274 to -0.535 ± 0.353 and -0.450 ± 0.346 D postoperatively (P < .05) after 1 and 12 months. No significant change was observed in the control group (P > .05). The average magnitude of surgically induced astigmatism (SIA) was 0.911 ± 0.442 and 0.811 ± 0.397 D at 1 and 12 months postoperatively, respectively, in the OCCI group, which was slightly lower than the target induced astigmatism. The difference in SIA between the OCCI and control groups was significant by the end of 1 and 12 months postoperatively (P < .0001). The mean correction index was below 1, suggesting an undercorrection effect caused by clear corneal incisions in the opposite direction. HOAs increased in both the control and OCCI groups after surgery (t = 5.668, P < .0001, t = 3.773, P = .0003, respectively), with oblique trefoil only significantly increasing in the OCCI group.

CONCLUSIONS

This study demonstrated that OCCIs represent a secure, efficient, reliable, and long-term technique for reducing preexisting low-to-moderate corneal astigmatism during ICL surgery. However, OCCIs did not show any advantageous impact in terms of wavefront aberrations when compared to the traditional single-incision method. The presence of oblique trefoil may be the main contributor to the alteration of HOAs during OCCI surgery. [J Refract Surg. 2024;40(1):e20-e29.].

Short-term clinic observation of misalignment and rotational stability after implantable collamer lens implantation

PURPOSE

We aimed to investigate misalignment (tilt and decentration) and rotational stability of the implantable collamer lens V4c 6 months after implantation and to explore the potential risk factors associated with postoperative misalignment and rotation.

METHODS

A total of 36 eyes of 36 patients with high myopia and myopic astigmatism who underwent implantable collamer lens V4c implantation were included in this study. Tilt, decentration, and rotation of the implantable collamer lens were assessed postoperatively at l week, 1 month, 3 months, and 6 months. Correlation analysis was used to identify the potential risk factors for implantable collamer lens tilt, decentration, and rotation at 6 months postoperatively. Higher-order aberration was measured to evaluate the effect of implantable collamer lens misalignment on visual quality at pupil diameters of 4.0 mm and 6.0 mm.

RESULTS

The tilt and decentration at the last follow-up were 2.43 ± 1.35° and 0.278 ± 0.160 mm, respectively. There was a significant positive correlation between tilt and decentration (r = 0.31, P = 0.046). No significant correlation was detected between implantable collamer lens decentration and internal higher-order aberrations (P > 0.05). The degree of implantable collamer lens rotation (3.11 ± 2.00°) was significantly associated with the vault (r =  - 0.422, P = 0.01), while it was positively associated with the preoperative anterior chamber depth (r = 0.36, P = 0.034). No significant correlation was found between postoperative astigmatism and rotation (r =  - 0.07, P = 0.351).

CONCLUSIONS

The implantable collamer lens V4c provides relatively stable misalignment and rotation after implantation. The ICL lens vault is a potential risk factor for postoperative implantable collamer lens rotation. The absolute value of decentration and tilt was relatively small, which showed no correlation with internal higher-order aberration in short-term observation.

Comparison of the optical quality vision between real post-LASIK myopic laser surgery and the simulated implantation of a phakic IOL in low myopia

A phakic intraocular lens (PIOL) of - 4.5 D was characterized from its wavefront aberration profile. A preclinical study was conducted using pre- and post-surgery data from four patients that had undergone myopic laser refractive surgery. All these patients would have needed a PIOL of - 4.5 D. Pre-surgery data were used to simulate the effect of a PIOL implantation. Post myopic refractive surgery data were used to calculate the post-LASIK eye model. Modulation transfer function (MTF), point spread function (PSF) and simulation of optotypes vision were obtained and compared. The PIOL did not worsen the optical quality of the eyes evaluated. High order Aberrations were always higher in the post-LASIK eye model. Optics quality trended to be better in PIOL implantation than post-LASIK surgery as pupil size increased.

Comparison of visual outcomes after non-toric and toric implantable collamer lens V4c for myopia and astigmatism

PURPOSE

To evaluate the visual quality of myopic patients after non-toric versus toric implantable collamer lens (ICL and TICL, respectively) V4c, and to investigate the potential risk factors of postoperative night vision disturbances.

METHODS

This prospective cohort study included 42 eyes of 21 patients treated with ICL and 46 eyes of 23 patients treated with TICL. Refractive parameters and ocular aberrations were examined before and 6 months after surgery. Subjective quality of vision was scored by a validated questionnaire.

RESULTS

The efficacy index at 6 months was 1.14 ± 0.20 for ICL and 1.17 ± 0.16 for TICL; the safety index was 1.20 ± 0.17 for ICL and 1.20 ± 0.19 for TICL. The root mean square of total higher-order aberrations (HOAs) and trefoil was significantly increased, and no statistical differences between groups were detected in HOA changes. Many patients reported haloes (85.7% for ICL and 100% for TICL) and glare (76.2% for ICL and 65.2% for TICL), but most (94.4% for ICL and 95.5% for TICL) were satisfied or very satisfied with visual outcomes. Implantable collamer lens (ICL) toricity was the risk factor for frequency (OR = 2.81, p = 0.01), severity (OR = 3.85, p = 0.003) and bothering effect (OR = 2.89, p = 0.01) of haloes.

CONCLUSIONS

Implantable collamer lens and TICL provided comparable efficacy, safety and predictability, induced acceptable level of HOAs and achieved high satisfaction in correcting myopia and myopic astigmatism. Although not severe, haloes and glare have a non-negligible prevalence and ICL toricity is a potential risk factor of haloes.

Monochromatic higher order aberrations in highly myopic eyes with Staphyloma

BACKGROUND

Prevalence of high myopia is continuously increasing, thus, patients affected with staphyloma are abundant worldwide. Assessment of the quality of vision in these patients is mandatory for a proper clinical counselling, specially when undergoing surgical procedures that require intraocular lenses implantation. Thus, the purpose of the study was to assess monochromatic higher order aberrations (HOAs) in highly myopic eyes with staphyloma with or without a dome-shaped macula.

METHODS

Participants underwent spectral-domain optical coherence tomography, ocular axial biometry, dual Scheimpflug photography and integrated Placido disk topography, and Hartmann-Shack wavefront analysis. Five groups were evaluated: a low-moderate myopia control group (< 6.00 diopters, n = 31) and four high myopia (≥6.00 diopters) groups: eyes without staphyloma (n = 18), eyes with inferior staphyloma (n = 14), eyes with posterior staphyloma without dome-shaped macula (n = 15) and eyes with posterior staphyloma with dome-shaped macula (n = 17). Subsequently, two new groups (including all participants) were created to assess differences between myopia with and without staphyloma. One-way analysis of covariance was performed using age and lens densitometry as covariates.

RESULTS

Statistically significant (p ≤ 0.05) differences in anterior corneal fourth-order HOAs were observed between the low-moderate myopia and no-dome-shaped macula (Mean: 0.16 μm) and dome-shaped macula posterior staphyloma groups (Mean: 0.12 μm) in younger patients (≤45 years old). The same groups also showed (p ≤ 0.05) significant differences for anterior corneal primary spherical aberration (Mean: 0.19 and 0.13 μm, respectively). In addition, anterior corneal tetrafoil was significantly higher (p = 0.04) in dome-shaped macula compared to no-dome-shaped macula (Mean: 0.18 vs 0.06 μm, respectively). When all participants were grouped together, significantly lower mean anterior corneal primary spherical aberration (0.15 μm vs. 0.27 μm, p = 0.004) and higher internal primary spherical aberration (0.04 μm vs. -0.06 μm, p = 0.04) was observed in staphyloma compared to no-staphyloma myopic patients.

CONCLUSIONS

Eyes with high myopia and staphyloma have less positive anterior corneal primary spherical aberration and less negative internal primary spherical aberration, suggesting that the anterior corneal surface tends to mimic in a specular fashion the posterior pole profile. This corneal behaviour appears to change in patients older than 45 years.

Comparison of objective and subjective visual quality early after implantable collamer lens V4c (ICL V4c) and small incision lenticule extraction (SMILE) for high myopia correction

PURPOSE

To investigate differences in the objective and subjective visual quality of patients with high myopia following implantable collamer lens V4c (ICL V4c) versus small incision lenticule extraction (SMILE) early postoperatively.

METHODS

This prospective analysis included 94 eyes of 57 patients (8 males) in the ICL V4c group (mean spherical equivalent (SE), -8.07 ± 1.03 dioptres (D)) and 103 eyes of 57 patients (13 males) in the SMILE group (mean SE, -7.85 ± 0.78 D). Refractive parameters and wavefront aberrations were recorded preoperatively and 6 months postoperatively. Subjective visual quality was scored with the Quality of Vision questionnaire, and operation satisfaction was evaluated 6 months postoperatively.

RESULTS

At 6 months postoperatively, the efficacy index was 1.17 ± 0.16 in the ICL and 1.09 ± 0.20 in the SMILE group; the safety index was 1.21 ± 0.18 in the ICL and 1.12 ± 0.16 in the SMILE group. A significant increase in total higher-order aberrations (HOAs) in both the ICL and SMILE groups was observed, but to a lesser degree in ICL (p < 0.05). In the ICL group, trefoil significantly increased (p < 0.05), whereas in the SMILE group, coma, trefoil and spherical aberration significantly increased (p < 0.05). Glare, haloes and blurred vision had the highest incidences after both types of surgery, and postoperative haloes were significantly more common following ICL; 96.1% of ICL-treated and 94.9% of SMILE-treated patients were satisfied with their visual outcomes.

CONCLUSION

ICL V4c caused lower HOAs induction than SMILE. Despite the postoperative visual disturbances, both ICL and SMILE provided good efficacy, safety, predictability and high satisfaction in correcting high myopia.

The effects of implantable collamer lens implantation on higher order aberrations

AIM

To evaluate the changes in higher order aberrations (HOAs) after implantable collamer lens (ICL; Staar Surgical, Nidau, Switzerland) implantation.

METHODS

Totally 30 eyes of 18 patients with myopia were included in this study with an average age of 25.77y (min: 21, max: 40). Refraction, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), HOAs (entire, corneal and internal) were evaluated preoperatively and three months postoperatively. Ocular aberrations were measured by using iTrace (Tracey Technology, Houston, Texas, USA). SPSS (IBM Corp. Released 2013. IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY: IBM Corp) was used for the statistical analysis and the interpretation of the data. P values of less than 0.05 were considered statistically significant.

RESULTS

The preoperative mean spherical power was -9.01 D (min: -5.00, max: -13.00) and the mean cylindrical error was -2.40 D (min: -0.50, max: -4.75). The postoperative mean residual spherical power was -0.73 D (min: -0.20, max: -1.75) and the mean cylindrical error was -0.89 D (min: -0.18, max: -2.09). Analyses were made on root mean square (RMS) values of total HOAs (tHOAs), spherical aberration, coma and trefoil as entire, corneal and internal components. The differences in entire tHOAs and in internal tHOAs were significant. There was no significant change found in spherical aberrations. The differences in entire coma and in internal coma were significant. There was no significant change found in corneal coma. With respect to trefoil, the only significant difference was in internal trefoil.

CONCLUSION

The ICL implantation corrects the refractive error successfully and changes entire and internal HOAs of the eye.

Comparative Study of Implantable Collamer Lens Implantation in Treating Four Degrees of Myopia: Six-Month Observation of Visual Results, Higher-Order Aberrations, and Amplitude of Accommodation

PURPOSE

To compare the visual and refractive outcomes, higher-order aberrations (HOAs), and amplitude of accommodation (AA) after implantable collamer lens (ICL) model V4c implantation in four degrees of myopia.

METHODS

One hundred and thirty-seven myopic eyes (137 patients) undergoing ICL implantation were included and divided into four groups: Group 1 with spherical equivalent (SE) ≤-6.0D, Group 2 with SE from -6.13D to -9.0D, Group 3 with SE from -9.13D to -12.0D, and Group 4 with SE from -12.13D to -18.0D. The postoperative visits were scheduled at 1 day, 1 week, 1 month, 3 months, and 6 months. Visual and refractive outcomes, HOAs and AA were observed and compared.

RESULTS

At 6 months postoperatively, the uncorrected distance visual acuity (UDVA) in Group 4 was worse than the values in the other groups (all p < .05). Meanwhile, Group 4 had more eyes with corrected distance visual acuity (CDVA) improvement than the other groups. Furthermore, 96%, 100%, 100%, and 81% of eyes had an SE within ±0.5D in Group 1, Group 2, Group 3, and Group 4 (p < .05 between Group 4 and the other groups), respectively. The postoperative UDVA and SE remained stable in all groups. No significant change in total HOAs was found between preoperative and postoperative values for each group. However, quatrefoil increased in each group, whereas trefoil was induced in all groups except for Group 1. Negative spherical aberration was induced in Group 3 and Group 4. AA significantly decreased 1 week postoperatively and gradually improved in each group. Although AA improved to the preoperative level in Group 1 at 3 months postoperatively, it was still lower than the preoperative level in the other groups.

CONCLUSIONS

In treating different degrees of myopia with ICL implantation, differences were observed in terms of CDVA improvement, SE predictability, HOAs induction, and accommodation recovery.

Ocular higher-order aberrations changes after implantable collamer lens implantation for high myopic astigmatism

Purpose

To investigate the changes in higher-order aberrations (HOAs) induced by the implantation of implantable collamer lenses (ICLs) and Toric ICL (TICL) in eyes with high myopia and high myopic astigmatism.

Methods

We investigated 33 eyes of 18 consecutive patients (in a prospective, interventional case series study), with spherical equivalent errors of -6.00 to -21.09 diopters (D) and cylindrical errors of -0.5 to -4.75 D, who underwent ICL and TICL implantation. Before and after 5 days, 2 and 6 months of surgery, the uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), defocus and adverse events of the surgery were assessed. Ocular HOAs were also evaluated by Hartmann-Shack aberrometry (Technolas PV, Rochester, New York, USA) before and after 6 months of surgery.

Results

At 6.0 months after surgery, the UCVA and BCVA in 40% and 66.7% of eyes were 20/20, respectively. Mean defocus refraction and astigmatism was reduced to -0.66 and 0.65 D from -12.79 and 2.18 at baseline, respectively. For a 6 mm pupil, HOAs were not significantly changed, merely from 0.417 ± 0.162 μ before surgery to 0.393 ± 0.119 μ after surgery (P = 0.45). Spherical aberration (Z400) increased significantly (P = 00.0). Surgical induced astigmatism was lower than 0.25 D, and there were no changes in trefoils and coma aberration. No vision-threatening complications occurred during the observation period.

Conclusion

This study shows that the ICL and TICL performed well in correcting high myopic astigmatism without significant changes in HOAs during a 6-month observation period, although the spherical aberration (Z400) increased significantly.

Management of a case of myopic foveoschisis with phakic intraocular lens (pIOL) in situ: intraoperative challenges

We describe the case of a 30-year-old man with pathological myopia with a phakic intraocular lens (IOL) (Visian ICL V4c model; STAAR, Monrovia, California, USA) in situ having complaints of metamorphopsia in the left eye with documented myopic foveoschisis on swept-source optical coherence tomography (DRI OCT Triton; Topcon, Tokyo, Japan). The patient underwent pars plana vitrectomy with internal limiting membrane peeling. This report discusses the intraoperative challenges occurring as a result of increased optical aberrations in the presence of a phakic IOL.

Effect of incision types for Artisan phakic intraocular lens implantation on ocular higher order aberrations

AIM

To evaluate the effect of incision types for Artisan phakic intraocular lens (PIOL) implantation on ocular higher-order aberrations (HOAs).

METHODS

A retrospective review was conducted of the patients who had undergone Artisan PIOL implantation for the correction of myopia and followed up for at least 6mo. Patients are classified into 2 groups considering the incision type: cornea group with patients undergone clear corneal incision; sclera group with patients undergone sclera tunnel incision. All patients with postoperative astigmatism of under 1 diopter (D) were included to minimize the effect of residual astigmatism on postoperative HOAs. Visual acuity, special equivalents, astigmatism, predictability (±1 D from target refraction), HOAs (coma, trefoil, spherical aberration), and corneal endothelial counts were analyzed preoperatively and 6mo postoperatively.

RESULTS

At the postoperative 6mo, all patients of both groups achieved uncorrected visual acuity of 16/20 or better, and significantly decreased the spherical equivalents compared with preoperative values. The predictability of refractive correction was 96% in the former, and 94% in the latter. Unlike the sclera group, preoperative astigmatism decreased significantly in cornea group at postoperative 6mo. The HOAs increased significantly at postoperative 6mo compared to the preoperative values in both groups, and the root mean square (RMS) total and trefoil wavefront aberration of cornea group were significantly higher than those of sclera group.

CONCLUSION

Although corneal incision significantly reduces preexisting astigmatism, the postoperative 6mo of total RMS and trefoil aberration change may deteriorate the visual quality after Artisan PIOL implantation.

Spherical aberration reduction in nuclear cataracts

PURPOSE

To measure higher-order aberrations (HOAs) in nuclear cataracts and to investigate spherical aberration changes with nuclear cataract progression.

METHODS

A total of 102 eyes of older subjects (>50 years) were classified based on the nuclear opalescence (NO) grading of the Lens Opacities Classification System III: Group 1 (< NO2, 35), 2 (NO2, 23), 3 (NO3, 23), and 4 (≥ NO 4:21 eyes). Wave front measurements were performed with a Hartmann-Shack aberrometer. To investigate lenticular spherical aberration, HOAs were examined in 28 eyes before and after phacoemulsification, followed by insertion of an aberration-free intraocular lens. The relationship between lens opacity grade and ocular and lenticular spherical aberrations were investigated.

RESULTS

Mean spherical aberrations in groups 1, 2, 3, and 4 were 0.25 ± 0.10, 0.16 ± 0.13, 0.12 ± 0.15, and 0.10 ± 0.20 μm, respectively, and showed a significant difference with nuclear opacity grading (p = 0.001). The spherical aberration showed negative associations with nuclear opacity grading (r = -0.408, p < 0.001). The predominant change in HOAs after phacoemulsification was an increase in spherical aberration, and 86 % of lenticular spherical aberrations were presumed to have negative values. The lenticular spherical aberration was negatively correlated with nuclear opacity severity (r = -0.409, p = 0.031).

CONCLUSIONS

Ocular spherical aberration decreases with the progression of nuclear cataracts due to the negative correlation between lenticular spherical aberration and nuclear opacity severity.

Optical quality comparison between 2 collagen copolymer posterior chamber phakic intraocular lens designs

PURPOSE

To compare the optical quality in vitro of 2 designs of the Visian Implantable Collamer Lens phakic intraocular lens (pIOL) for different powers and optical apertures.

SETTING

University of Valencia, Valencia, Spain.

DESIGN

Experimental study.

METHODS

The Nimo TR1504 deflectometry device was used to measure the V4c pIOL, which has a smaller optic diameter, and the V5 pIOL, which has a larger optic diameter. The pIOLs were measured for -3.00 diopters (D), -6.00 D, -9.50 D, and -10.50 D at different optical apertures from 3.00 to 6.00 mm depending on the IOL power and model. The root mean square of higher-order aberrations (RMS HOAs) was analyzed. The Strehl ratio, point-spread functions (PSFs), and simulated images were calculated from wavefront aberrations.

RESULTS

There were no statistically significant differences in any Zernike RMS or RMS HOAs between the 2 pIOL models with the same power and optical aperture (P > .05). Both pIOLs had negative spherical aberration that increased with the pIOL power. Strehl ratio values showed no statistically significant differences between the pIOLs with the same power and pupil aperture. Minimal differences were seen in the PSFs and simulated images between the pIOLs.

CONCLUSIONS

Both pIOLs showed good and comparable in vitro optical quality similar that of a perfect lens in that they should not affect visual performance after implantation. Patients with larger pupil diameters could benefit from the pIOL with the larger optic diameter because it showed better in vitro optical quality than the previous design with a smaller optic diameter.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Simulated prototype of posterior chamber phakic intraocular lens for presbyopia correction

PURPOSE

To evaluate the visual impact of adding different spherical aberration values to an Implantable Collamer Lens phakic intraocular lens (pIOL) to increase the depth of focus using an adaptive optics visual simulator.

SETTING

University of Valencia, Valencia, Spain.

DESIGN

Experimental study.

METHODS

Wavefront aberrations in -3.00 D and -6.00 diopter (D) pIOLs were measured in vitro. Afterward, different simulated pIOL experimental prototypes were created along with variances in the spherical aberration. An adaptive optics visual simulator was used to simulate vision after the implantation of the different pIOL prototypes from their wavefront aberrations. The corrected distance visual acuity (CDVA) and depth of focus were measured in 3.0 and 4.5 mm pupils.

RESULTS

In a 3.0 mm pupil, the CDVA achieved with -3.00 and -6.00 D pIOLs and all pIOL prototypes evaluated was above 20/20 except for a -6.00 D pIOL + spherical aberration 4 at 50% CDVA contrast, which decreased to 20/25. However, in a 4.5 mm pupil, the CDVA obtained with the pIOL prototypes decreased significantly and was more pronounced when the spherical aberration induced was negative. The depth of focus increment was larger with the highest spherical aberration added and with a small pupil. Nevertheless, it was independent of the sign of the added spherical aberration.

CONCLUSIONS

The outcomes show that residual negative spherical aberration after pIOL implantation will disrupt the CDVA. However, some residual positive spherical aberration after pIOL implantation increased the depth of focus with excellent CDVA, providing a possible pIOL design for young presbyopic patients.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Visual outcomes in adult amblyopic eyes with moderate myopia after corneal laser surgery versus copolymer phakic intraocular lens implant

PURPOSE

To assess visual acuity and refractive correction in moderately myopic adult eyes with suboptimal preoperative corrected distance visual acuity (CDVA) after laser in situ keratomileusis (LASIK) or insertion of a posterior chamber Implantable Collamer Lens phakic intraocular lens (pIOL).

SETTING

Clínica Baviera, Instituto Oftalmológico Europeo, Torrevieja Hospital, Madrid, Spain.

DESIGN

Retrospective study.

METHODS

The study sample included 1310 eyes that had LASIK and 94 that had insertion of a pIOL from July 2002 to September 2013. Suboptimal preoperative CDVA was defined as equal to logMAR 0.15 or below and moderate myopia as a spherical equivalent of -5.0 to -10.0 diopters (D).

RESULTS

The preoperative mean CDVA was 0.22 logMAR ± 0.09 (SD) in the LASIK group and 0.23 ± 0.09 logMAR in the pIOL group. Postoperative uncorrected distance visual acuity (UDVA) was 0.13 ± 0.12 logMAR in the laser group and 0.12 ± 0.09 logMAR in the pIOL group, with a postoperative CDVA of 0.11 ± 0.10 logMAR and 0.08 ± 0.07 logMAR, respectively.

CONCLUSIONS

Compared with preoperative values, amblyopic eyes with moderate myopia having LASIK or implantation of a pIOL demonstrated a statistically significant improvement in UDVA and CDVA (P < .001). The pIOL group performed significantly better than the LASIK group in terms of safety and efficiency.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Optical quality of hyperopic and myopic phakic intraocular lenses

AIMS

To assess and compare the optical quality of the myopic and hyperopic implantable collamer lens (ICL) from its wavefront aberrations for different powers and pupil diameters.

SETTINGS AND DESIGN

Prospective study.

MATERIAL AND METHODS

The wavefront aberrations of two myopic (-3 and -6 diopters (D)) and two hyperopic V4b ICLs (+3 and +6D) were measured in vitro. To assess and compare the optical quality of different powers of ICLs, we analyzed the root mean square (RMS) of total higher order aberrations (HOAs), trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration at 3- and 4.5-mm pupil. In addition, the point spread functions (PSFs) of each ICL evaluated were calculated from the wavefront aberrations at 3- and 4.5-mm pupil.

STATISTICAL ANALYSIS

A Student's t-test for unpaired data was used for comparison between myopic and hyperopic ICLs.

RESULTS

Myopic ICLs showed negative spherical aberration, in contrast hyperopic ICLs showed positive spherical aberration, which increases when the ICL power increases, due to the innate optical properties of the lens. All ICLs evaluated had negligible amounts of other aberrations. We did not find statistical significant differences in any Zernike coefficient RMS values analyzed between myopic and hyperopic ICLs at 3- and 4.5-mm pupil (P > 0.05).

CONCLUSIONS

Myopic and hyperopic ICLs provide good and comparable optical quality for low to moderate refractive error. The ICLs evaluated showed values of wavefront aberrations clinically negligible to affect the visual quality after implantation.

Intraocular pressure after implantation of the Visian Implantable Collamer Lens With CentraFLOW without iridotomy

PURPOSE

To compare the intraocular pressure (IOP) values during a 3-month period after implantation of the new Visian Implantable Collamer Lens (ICL; STAAR Surgical Company, Nidau, Switzerland) V4c design with CentraFLOW technology without iridotomy using a standard procedure followed by implantation of the conventional ICL V4b model.

DESIGN

Retrospective cohort study.

METHODS

This study included 17 eyes implanted with the ICL V4b model and 18 eyes implanted with the ICL V4c model. The mean preoperative spherical equivalent refractions were -7.48 ± 5.00 diopters and -8.66 ± 4.2 diopters, respectively. We compared the best-corrected distance visual acuity before surgery with the uncorrected distance visual acuity after surgery. The intraocular pressure (IOP) was measured 1 week, 1 month, and 3 months after surgery. The central vault at 3 months was measured using optical coherence tomography.

RESULTS

Three months after surgery, the mean uncorrected distance visual acuities were -0.09 ± 0.12 logarithm of the minimal angle of resolution units with the V4b and -0.07 ± 0.11 logarithm of the minimal angle of resolution units with the V4c. The mean distances between the ICL and the anterior crystalline lens surface were 557 ± 224 μm and 528 ± 268 μm for the V4b and V4c, respectively (P = .73). After 1 week and 1 month, the mean IOPs were 13.7 and 13.3 mm Hg and 14.7 and 15.1 mm Hg, respectively. There were no significant differences in IOP within or between groups during the follow-up period (P > .05, for all comparisons).

CONCLUSIONS

The new ICL with the CentraFLOW design seems to provide similar results as its predecessors for the correction of moderate to high myopia and maintenance of safe IOP levels without iridotomy.

Visian implantable contact lens versus AcrySof Cachet phakic intraocular lenses: comparison of aberrmetric profiles

Purpose

To evaluate the in vivo aberrometric performance of two phakic intraocular lenses (PIOLs); the Visian implantable contact lens (ICL) and the AcrySof Cachet PIOL.

Methods

Thirty eight eyes from 29 patients with an age range of 23–32 years and more than 9 D of myopia were divided into two groups; one group of 20 eyes received a Visian ICL model V4c, another group of 18 eyes received an AcrySof Cachet PIOL. Total higher order aberrations (HOAs) root mean square, total coma, and total spherical aberrations were recorded pre and 6 weeks postoperatively to evaluate and compare the aberrometric performance of the Visian ICL and the AcrySof Cachet PIOL implanted in highly myopic patients.

Results

Preoperatively, there were no significant differences in any studied parameters, except for preoperative spherical equivalent. Postoperatively, there were no statistically significant differences in the induction of HOAs between both PIOLs. The reduction in spherical aberrations was statistically significant in each group as well as in all study patients.

Conclusion

Both AcrySof Cachet PIOL and ICLs are effective phakic implants to correct high refractive errors. They both induce small amounts of negative spherical aberration that do not affect the total HOAs, yet reduce the positive ocular spherical aberration. This result is expected to improve the quality of vision in such patients.

Optical quality comparison of conventional and hole-visian implantable collamer lens at different degrees of decentering

PURPOSE

To compare the optical quality of implantable Collamer lens (ICL) with and without central hole (Hole ICL and conventional ICL) at different degrees of decentering.

DESIGN

Experimental laboratory investigation.

METHODS

Wavefront aberrations of the -3, -6, and -12 diopter (D) V4b and -3, -6, and -12 D V4c ICLs were measured in 3 conditions-centered and decentered 0.3 and 0.6 mm-at 3-mm and 4.5-mm pupils. The root mean square of total higher order aberrations, trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration were evaluated. In addition, point spread function and simulated retinal images of ICLs were calculated from the wavefront aberrations for each ICL and all conditions of decentering at 4.5-mm pupil.

RESULTS

No statistically significant differences in any Zernike coefficient terms evaluated were found between conventional and Hole ICLs for any ICL powers and pupils evaluated (P > .05). We could not appreciate differences in the point spread function images and in simulated retinal images. Regarding the effect of the ICL decentration, coma aberration increased significantly with ICL decentration (P < .05), although these differences were not visible in the point spread function images and simulated retinal images. The ICL decentration was affected in the same manner on the conventional and Hole ICLs.

CONCLUSIONS

The outcomes showed good and comparable optical quality of the conventional and Hole ICLs for all ICL powers evaluated. Despite that coma aberration increased with ICL decentering, these values were clinically negligible and did not have a significant effect on the simulated visual performance.

Optical and visual quality of the visian implantable collamer lens using an adaptive-optics visual simulator

PURPOSE

To evaluate visual and optical quality of the implantable collamer lens for different powers and sizes of incision surgery.

DESIGN

Prospective study in humans.

METHODS

An adaptive optics visual simulator was used to measure 3 powers of implantable collamer lenses and simulate the implantable collamer lens wavefront aberration's pattern for small- and large-incision surgery. Visual acuity (VA) and contrast sensitivity were measured in 11 observers for 3- and 5-mm pupils. Modulation transfer function, point spread function, and Strehl ratio were calculated.

RESULTS

At 3 mm pupil, no statistically significant differences were found between both incision sizes for any implantable collamer lens power, except for -15 diopter (D) implantable collamer lens at 25 cycles/degree (cpd) (P < .05). At 5 mm pupil, statistically significant differences in Strehl ratio, VA, and contrast sensitivity were found between both incision sizes for all implantable collamer lens powers (P < .05). The outcomes were better with small incision. Implantable collamer lens power also affected the optical and visual quality. At 3 mm pupil, no statistically significant differences were found in VA and contrast sensitivity between implantable collamer lens powers, except between -3 and -15 D at low-contrast VA and at 20 and 25 cpd (P < .05). At 5 mm pupil, no statistically significant differences were found in Strehl ratio, VA, and contrast sensitivity between -3 and -6 D implantable collamer lens, but they did become apparent for -15 D implantable collamer lens for both incision sizes, all contrasts and spatial frequencies (P < .05).

CONCLUSIONS

The implantable collamer lens provides good optical and visual quality, although these outcomes decreased with large-incision surgery because of the increase of aberrations.

Myopic astigmatism correction: comparison of a Toric Implantable Collamer Lens and a bioptics technique by an adaptive optics visual simulator

PURPOSE

To compare the optical and visual quality of a simulated Toric Implantable Collamer Lens (TICL) and a bioptics technique to treat high myopic astigmatism.

METHODS

An adaptive optics visual simulator was used to simulate the vision after TICL implantation and a bioptics procedure from the wavefront aberration pattern for moderate and high-myopic astigmatism. Visual acuity (VA) at different contrasts and contrast sensitivity (CS) at 10, 20 and 25 cycles degree(-1) were measured for 3 and 5-mm pupils. Modulation Transfer Function (MTF) and Point Spread Function (PSF) were calculated for a 5-mm pupil.

RESULTS

At a 3-mm pupil we only found statistically significant differences in VA between the two simulated surgeries at low-contrast for moderate- and high-myopic astigmatism (p < 0.05). Statistically significant differences were found in CS at 3-mm pupil between both procedures at the highest spatial frequency for moderate-myopic astigmatism and at all frequencies for high-myopic astigmatism (p < 0.05). At a 5-mm pupil we found statistically significant differences in VA and CS between both simulated surgeries at all contrasts and frequencies evaluated for both groups (p < 0.05). In all cases VA and CS were better with the TICL than with the bioptics technique. MTFs for the bioptics technique were worse than those computed for the TICL. The TICL showed less spread out of the PSF than the bioptics procedure.

CONCLUSIONS

Simulated TICL and bioptics procedures provided good optical and visual quality, although TICL implantation provided slightly better outcomes than the bioptics procedure, especially when the pupil diameter was increased.

Optical quality of the Visian Implantable Collamer Lens for different refractive powers

PURPOSE

To evaluate the optical quality of the Visian Implantable Collamer Lens (ICL) for different powers and pupil diameters.

METHODS

Wavefront aberrations of the -3, -6, -9, -12 and -15 diopters (D) V4b ICLs were measured at 3- and 4.5-mm pupils. The root mean square (RMS) of total higher order aberrations (HOAs), trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration were evaluated. In addition, modulation transfer function (MTF) of the five ICL powers was measured for a 3-mm pupil. The point spread functions (PSFs) of each ICL evaluated was calculated from the wavefront aberrations at 4.5-mm pupil.

RESULTS

The ICLs evaluated had negative spherical aberration and negligible amounts of other aberrations. The negative spherical aberration increases when the ICL power increases being related with its innate optical properties. At 3-mm pupil, no statistically significant differences between ICLs were found for all the Zernike coefficient RMS values analyzed (p > 0.05). At 4.5-mm pupil, significant RMS values for the spherical aberration and total HOAs were found between medium-low and high powers (p < 0.05). Similar MTFs were obtained for all ICLs, although they slightly worsened when increased the ICL power.

CONCLUSIONS

ICLs evaluated provide good optical quality in terms of wavefront aberrations, MTF, and PSF. Although spherical aberration increases with ICL power, these values are clinically negligible to affect the visual quality after its implantation.

Optical and visual quality comparison of implantable Collamer lens and laser in situ keratomileusis for myopia using an adaptive optics visual simulator

Purpose. To compare optical and visual quality of the implantable Collamer lens (ICL) and laser in situ keratomileusis (LASIK) for myopia. Methods. An adaptive optics visual simulator (CRX1, Imagine Eyes, France) was used to simulate the vision after ICL implantation and LASIK procedure from the wavefront aberration pattern for -3 and -6 D. Monocular visual acuity (VA) at different contrasts and contrast sensitivity (CS) at 10, 20, and 25 cycles/degree (cpd) were measured for 3- and 5-mm pupils. Modulation transfer function (MTF) and point spread function (PSF) were calculated for a 5-mm pupil. Results. The ICL showed a MTF near of diffraction-limited MTF, but the post-LASIK of MTF worsened moving away from both curves. Statistically significant differences were found in VA between both procedures for all conditions (p<0.05). For -3 D ICL and LASIK, we did not find statistically significant differences in CS between the procedures for both pupils and any spatial frequencies (p>0.05). But for -6 D ICL and LASIK, the effect of aberrations became apparent, finding statistically significant differences in CS between both procedures for 2 pupils and all spatial frequencies evaluated (p<0.05). In all cases optical and visual quality was better with the ICL procedure. Conclusions. Both ICL and LASIK procedures provide good optical and visual quality, although the ICL provides better outcomes, especially for large refractive errors and pupil sizes. These outcomes are due to the LASIK procedure inducing higher higher-order aberrations than ICL implantation.

Preliminary in vivo positional analysis of a posterior chamber phakic intraocular lens by optical coherence tomography and its correlation with clinical outcomes

Purpose

To analyze by spectral-domain optical coherence tomography the anatomical relationship of a specific type of posterior chamber phakic intraocular lens (pIOL) implanted in cases of high to moderate myopia with the adjacent intraocular structures and to correlate it with clinical outcomes.

Methods

Prospective observational case series including 18 eyes with high to moderate myopia (spherical equivalent between −5.88 and −15.75 D) of 9 patients (age range, 29–49 years) undergoing bilateral Phakic Refractive Lens (PRL, Zeiss) implantation. Postoperative visual acuity, refraction, contrast sensitivity (CS), and ocular higher order aberrations (HOA) were evaluated. Furthermore, the in vivo position of the PRL was analyzed by means of spectral domain optical coherence tomography (3D OCT-1000, Topcon). Central (CENV), temporal (TEMV) and nasal vault (NASV) were measured. Correlation of these anatomical parameters with clinical data was also investigated. Mean follow-up was 47 ± 25 months.

Results

A statistically significant visual and refractive improvement (p < 0.01) was found postoperatively. Mean postoperative CENV, NASV, and TEMV were 157.88 ± 69.93 μm, 168.29 ± 65.02 μm, and 188.59 ± 55.99 μm, respectively. Significant difference was found between NASV and TEMV (p = 0.01). No significant correlations were found between ocular aberrometric and anatomical parameters (p ≥ 0.12). CENV, NASV and TEMV correlated significantly with 6-cycles per degree (cpd) photopic CS as well as with 18-cpd low mesopic CS (r ≥ 0.57, p ≤ 0.04). Furthermore, NASV also correlated significantly with preoperative anterior chamber depth (r = −0.65, p = 0.01).

Conclusions

This posterior chamber pIOL shows a trend to nasal position, with potential impact on refractive and visual outcomes, particularly in eyes with deep anterior chambers.