Matched Population Comparison of the Visian Implantable Collamer Lens and Standard LASIK for Myopia of -3.00 to -7.88 Diopters

Dynamic Stimulation Aberrometry: Objectively Measured Accommodation and Pupil Dynamics after Phakic Iris-Fixated Intraocular Lens Implantation

Purpose

Anterior iris-claw phakic intraocular lens (pIOL) implantation is a treatment option for refractive, ametropic patients. However, the postoperative accommodative ability has not been systematically researched. Dynamic stimulation aberrometry allows the objective and dynamical measurement of accommodation by observing ocular aberrations during the accommodation process. We investigated the dynamic accommodative ability after pIOL implantation compared with a healthy age- and gender-matched control group.

Design

Clinical, comparative case-control study.

Subjects

We included patients aged 18-50 years that either underwent pIOL implantation > 1 month ago or served as a healthy, phakic control group.

Methods

The accommodative ability and pupil dynamics of both groups were investigated using dynamic stimulation aberrometry. The method allows the analysis of dynamic parameters during accommodation, such as the accommodation speed. A 1:1 propensity score matching was conducted based on the patients' age and gender.

Main Outcome Measures

Parameters of objective accommodation, such as accommodative amplitude and pupil dynamic during accommodation.

Results

Fifty-eight healthy, phakic eyes < 50 years of age and 21 eyes after pIOL implantation to correct myopia (pIOL, Verisyse, AMO, Inc) were enrolled. Patients that underwent anterior pIOL implantation were examined on average 24 ± 18 months after surgery. After matching, the mean age of both groups was not significantly different (35 ± 8 vs. 34 ± 8 years). No significant difference in dynamic parameters of accommodation or the accommodative amplitude (2.8 ± 1.4 and 2.9 ± 1.4 diopters [D] for pIOL and control group, P = 0.82) were seen. Maximum and minimum pupil sizes were not significantly different. The change in pupil size during deaccommodation was significantly faster in patients after pIOL implantation (P < 0.001).

Conclusions

Dynamic stimulation aberrometry allowed the objective, dynamic, measurement of wavefronts in subjects with accommodative amplitudes up to 7 D. Phakic intraocular lens implantation does not impair the accommodative ability. It alters pupil dynamics during deaccommodation.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Evaluation of phakic intraocular lens power calculation using the new Linz-Homburg-Castrop formula and comparison with four conventional methods

PURPOSE

To evaluate the accuracy of phakic intraocular lens (pIOL) power calculation in a middle European patient cohort.

SETTING

EyeLaser Clinic, Linz, Austria.

DESIGN

Single-center single-surgeon retrospective consecutive case series.

METHODS

Patients were included after uneventful pIOL surgery implanting 91 nontoric and toric Visian implantable collamer lens model V4c. Online Calculation and Ordering System (OCOS) software, JPhakic software, Olsen-Feingold formula, Holladay formula, and Linz-Homburg-Castrop (LHC) formula were compared. When possible, lens constants were optimized for the patient cohort. Data of single eye per patient were included. Outcome measures were mean absolute prediction error, median absolute prediction error, mean prediction error with SD, and median prediction error, as well as the percentage of eyes with an absolute prediction error within limits of 0.25 diopters (D), 0.5 D, 0.75 D, and 1.0 D.

RESULTS

91 eyes of 91 patients were assessed. After application of the Cochran Q test, the Olsen-Feingold formula achieved a significantly lower percentage of eyes within an absolute prediction error of 1.0 D than all other methods.

CONCLUSIONS

In the patient cohort, OCOS software, JPhakic software, and Holladay and LHC formulas showed equal results and can be cross-checked. The LHC formula was not published before. A ready-to-use Excel sheet is available as an addendum.

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.

Posterior chamber toric implantable collamer lenses vs LASIK for myopia and astigmatism: systematic review

This systematic review compares the visual and refractive outcome of laser in situ keratomileusis with (toric) implantable collamer lens (ICL) in the treatment of myopic astigmatism. An electronic literature search led to 19 comparative articles. Refractive outcome, efficacy, safety, predictability, and stability as well as differences in contrast sensitivity and higher-order aberrations (HOAs) were analyzed for moderate (-3 to -6 diopters [D]) and high (≥-6 D) myopia. Results were either significantly in favor of (toric)-ICL or equal. Fewer HOAs and better contrast sensitivity after (toric)-ICL seem to be the largest asset in its refractive and clinical superiority. However, longer follow-up studies are indicated, specifically for systematically comparing long-term adverse effects.

A Nationwide Multicenter Study on 1-Year Outcomes of Posterior Chamber Phakic Intraocular Lens Implantation for Low Myopia

Purpose

To assess the nationwide multicenter outcomes of posterior chamber phakic intraocular lens implantation with a central hole (EVO-ICL, STAAR Surgical) for patients with low myopia.

Methods

This multicenter study comprised 172 eyes of 111 consecutive patients undergoing hole ICL implantation to correct low myopia and myopic astigmatism [manifest spherical equivalent (MSE);-3 diopters (D) or less] at seven nationwide major surgical facilities. We retrospectively determined safety, efficacy, predictability, stability, and adverse events at 1 week, 1, 3, 6, and 12 months postoperatively, and at the final visit.

Results

The mean follow-up period was 1.4 ± 1.0 years. Uncorrected and corrected visual acuities at 1 year postoperatively were -0.17 ± 0.12 and -0.24 ± 0.07 logarithm of the minimal angle of resolution (logMAR), respectively. At 1 year postoperatively, 91% and 100% of eyes were within 0.5 and 1.0 D of the target correction, respectively. No significant manifest refraction changes of -0.07 ± 0.26 D occurred from 1 week to 1 year. No vision-threatening complications occurred at any time in this series.

Conclusions

According to our experience, the EVO-ICL performed well without significant complications throughout the 1-year observation period, even for the correction of low myopia. It is suggested that current ICL implantation is one of the viable surgical options for correcting low myopia.

Comparison of the visual performance of iris-fixated phakic lens and implantable collamer lens to correct high myopia

Background

To compare visual performance between the iris-fixated phakic intraocular len (pIOL) and implantable collamer len (ICL) to correct high myopia.

Methods

Twenty-four eyes underwent iris-fixated pIOL implantation and 24 eyes underwent ICL implantation. At the 6-month follow-up, the best-corrected visual acuity (BCVA) and uncorrected distance visual acuity (UDVA) were compared between the iris-fixated pIOL and ICL groups. The objective scatter index (OSI), modulation transfer function (MTF) cutoff, and ocular aberrations were performed to evaluate postoperative visual quality between the two groups.

Results

No significant difference was found in UDVA, BCVA, and spherical equivalent between the iris-fixated pIOL and ICL groups (P > 0.05). Six months after surgery, the following values were significantly higher in the ICL group than in the iris-fixated pIOL group: MTF cutoff, strehl ratio and optical quality analysis system values at contrasts of 9 %, 20 %, and 100 % (P < 0.01). The OSI in the iris-fixated pIOL group was higher than in the ICL group 6 months after surgery (P < 0.01). All high-order aberrations were slightly more severe in the iris-fixated pIOL group than in the ICL group 6 months after surgery, although only trefoil (P = 0.023) differed significantly in this regard.

Conclusions

Both iris-fixated lenses and ICLs can provide good visual acuity. ICLs confer better visual performance in MTF-associated parameters and induce less intraocular light scattering than iris-fixated pIOLs.

Posterior chamber collamer phakic intraocular lens implantation: Comparison of efficacy and safety for low and moderate-to-high myopia

PURPOSE

To compare visual, refractive and safety outcomes of central-hole posterior chamber collamer phakic intraocular lens implantation for low and moderate-to-high myopia.

SUBJECTS/METHODS

This retrospective cohort study included 338 eyes submitted to posterior chamber collamer phakic intraocular lens implantation that completed a 12-month postoperative follow-up. Two groups were defined depending on preoperative spherical equivalent: group 1 comprised 106 eyes with manifest spherical equivalent of -6.00 D or less; group 2 comprised 232 eyes with manifest spherical equivalent higher than -6.00 D. Effectiveness, predictability, stability and safety outcomes were compared preoperatively and at 1, 6 and 12 months postoperatively.

RESULTS

At 1-year postoperative, uncorrected and corrected visual acuities were 0.02 ± 0.17 and -0.01 ± 0.12 logMAR (group 1) and 0.04 ± 0.20 and 0.01 ± 0.16 logMAR (group 2), with an efficacy index of 1.05 ± 0.17 and 1.17 ± 0.28. Respectively, 92 (86.8%) and 199 (85.8%) eyes were within ±0.50 D of targeted refraction, and postoperative manifest refraction changes were -0.07 ± 0.25 D and -0.07 ± 0.35 D. Intraocular pressure did not change significantly. The mean rate of endothelial cell loss was 1.12% and 1.10%, respectively. One case of anterior subcapsular cataract (group 2) was observed. ICL exchange occurred in one case (group 1) and three cases (group 2). No vision-threatening complications were reported.

CONCLUSION

The posterior chamber collamer phakic intraocular lens implantation demonstrated high visual and refractive efficacy with an excellent safety profile for the correction of both low and moderate-to-high myopia, revealing equivalent 1-year outcomes regardless of the degree of preoperative myopia.

Phakic intraocular lens implantation for the correction of hyperopia

The prevalence of myopia is much higher than hyperopia. Hence, there are relatively few studies investigating phakic intraocular lens (pIOL) implantation for the correction of hyperopia. This review aimed to summarize the available relevant literature on the efficacy and safety of pIOL implantation for the correction of hyperopia and hyperopic astigmatism. At present, two types of pIOLs are used to correct hyperopia and hyperopic astigmatism: anterior chamber iris-fixated pIOLs and posterior chamber implantable collamer lenses. Both have been found to be safe and effective. No serious events (eg, retinal or choroidal detachment, endophthalmitis) were reported in the reviewed articles. Implantation of pIOLs might be the optimal refractive surgery for the correction of high hyperopia.

One-year natural course of corneal densitometry in high myopic patients after implantation of an implantable collamer lens (model V4c)

BACKGROUND

Corneal densitometry, which is also known as corneal backscattering, is a surrogate measure of corneal clarity. The purpose of the study was to investigate the changes in corneal densitometry (CD) after implanting an implantable collamer lens (ICL-V4c).

METHOD

Twenty-six high myopic patients (aged 29.3 ± 6.6 years, 6 males and 20 females) who underwent ICL-V4c implantation were enrolled. Intraocular pressure (IOP), corneal topography, corneal densitometry, uncorrected distance visual acuity (UCDVA), manifest refraction, and best corrected distance visual acuity (BCDVA) were evaluated pre-operatively and at 1 day, 1 week, and 1, 3, 6, and 12 months post-operatively. Endothelial cell density (ECD) was measured pre-operatively and at 3, 6, and 12 months post-operatively. The efficacy index (mean post-operative UCDVA / mean pre-operative BCDVA) and the safety index (mean post-operative BCDVA / mean pre-operative BCDVA) were evaluated at 1 month, 3 months, 6 months and 12 months post-operatively.

RESULTS

Over the annular diameters of 0-2 mm, the pre-operative densitometry values of the anterior layer, central layer, posterior layer, and total layer were 20.1 ± 2.8, 11.8 ± 1.1, 10.5 ± 0.9 and 14.1 ± 1.5, respectively. From pre-operatively to post-operative Month 12, the values changed insignificantly (P = 0.177, P = 0.153, P = 0.543 and P = 0.207, respectively). Over the annular diameters of 2-6 mm, the pre-operative mean densitometry values were 17.9 ± 2.2, 10.5 ± 0.9, and 12.6 ± 1.2, respectively. From pre-operatively to post-operative Month 12, the values decreased to 16.5 ± 2.1, 10.0 ± 0.9, and 11.9 ± 1.2, respectively, which were similar to the pre-operative values (all P > 0.05) but significantly lower than the values obtained at post-operative Day 1 (P = 0.013, P = 0.002 and P = 0.010, respectively). The densitometry value of the posterior layer over the annular diameters of 2 to 6 mm remained unchanged (from 9.4 ± 0.7 to 9.1 ± 0.7) over time (P = 0.372). The efficacy and safety indices assessed at 12 months post-operatively were 1.04 ± 0.27 and 1.19 ± 0.23, respectively. The changes in IOP and ECD values were statistically insignificant (P = 0.896 and P = 0.968, respectively).

CONCLUSION

ICL-V4c implantation may be safe and efficient for high ametropia correction. The corneal densitometry values obtained over the annulus of 0-6 mm increased slightly from before the operation to post-operative Day 1 and then decreased gradually, which indicates that ICL-V4c implantation may not compromise corneal clarity.

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.

Contralateral eye comparison of the long-term visual quality and stability between implantable collamer lens and laser refractive surgery for myopia

Purpose

To investigate the long‐term visual quality and stability of implantable collamer lens (ICL) and laser refractive surgery (LRS) for myopia.

Methods

This study comprised 52 eyes of 26 high‐myopia anisometropia patients who were suitable for surgical treatment. In each patient, the higher‐myopia eye was implanted with ICL and the lower‐myopia eye was treated with LRS. The patients were followed for 3 years. During that time period, uncorrected (UDVA) and corrected distance visual acuity (CDVA), refraction, wavefront aberration and visual quality were evaluated.

Results

The spherical equivalent refractive error changed from −14.11 ± 3.39 D preoperatively to −1.27 ± 1.05 D 3 years after ICL implantation and from −8.75 ± 2.76 D to −1.12 ± 1.30 D after LRS. The changes in refractive error from 1 month to 3 years were −0.52 and −0.77 D for the ICL and LRS groups, respectively. The safety indices (postoperative CDVA/preoperative CDVA) were 1.84 ± 1.00 and 1.32 ± 0.40, and the efficacy indices (postoperative UDVA/preoperative CDVA) were 1.40 ± 1.10 and 1.11 ± 0.44, respectively. The postoperative coma, spherical and total higher‐order aberrations in the ICL group were lower than those in the LRS group.

Conclusion

Both ICL implantation and LRS are safe and effective procedures for myopia with suitable indications, but ICL implantation is more stable. Fewer induced aberrations are gained after ICL implantation.

Prospective Randomized Multicenter Comparison of the Clinical Outcomes of V4c and V5 Implantable Collamer Lenses: A Contralateral Eye Study

Purpose

To compare the visual and refractive outcomes and night vision performance questionnaire results between V4c and V5 implantable Collamer lenses in a prospective, randomized, multicenter study.

Settings

Four refractive surgery centers.

Design

Prospective randomized multicenter single-masked comparative study.

Methods

Twenty-three patients were enrolled in this study. A conventional V4c model (EVO Visian ICL) was implanted in one eye, and a V5 model (EVO+ Visian ICL), which has a larger optic diameter than the V4c model, was implanted in the contralateral eye. The uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were evaluated before and 6 months after surgery. At 6 months after surgery, a questionnaire on night vision disturbances was administered. The efficacy, safety, and predictability of the two implanted ICL models were compared.

Results

There were no significant differences in the postoperative UDVA and CDVA between the two ICL models. The mean efficacy indexes for the V4c and V5 lenses were 1.16 ± 0.22 and 1.03 ± 0.23, respectively. The mean safety indexes of the V4c and V5 lenses were 1.21 ± 0.20 and 1.19 ± 0.20, respectively. The night vision performance questionnaire revealed that 7 patients (37%) noticed a difference in visual performance between the eyes, and all of them reported that they could see better at night with the V5-implanted eye compared with the V4c-implanted eye.

Conclusion

The V4c and V5 ICL models achieved similar visual and refractive outcomes, whereas the V5 model showed a possible advantage in reducing night vision disturbances.

Refractive outcomes and optical quality after implantation of posterior chamber phakic implantable collamer lens with a central hole (ICL V4c)

Background

To investigate refractive outcomes and optical quality after implantation of posterior chamber phakic implantable collamer lens with a central hole (ICL V4c) to correct high myopia.

Methods

Sixty seven eyes of 38 patients who underwent ICL V4c implantation were enrolled. The mean preoperative spherical equivalent (SE) was − 12.44 ± 3.15 D (range: − 6.63 to − 20.50 D). The refractive outcomes and optical quality of the eyes at postoperative 1 and 3 months were evaluated and compared.

Results

At 3 months postoperatively, the mean safety and efficacy indexes were 1.33 ± 0.22 and 1.14 ± 0.23, respectively. The mean SE was − 0.32 ± 0.52 D; no patient lost 1 or more lines of corrected distance visual acuity (CDVA), 13% remained unchanged, 45% gained 1 line and 42% gained 2 or more lines. The mean modulation transfer function cutoff frequency (MTF_cutoff), Strehl in two dimensions ratio, and objective scatter index (OSI) were 38.20 ± 9.96 cycles per degree, 0.21 ± 0.06, and 1.00 ± 0.73, respectively. No significant difference was found in any of the above parameters (P > 0.05) between 1 and 3 months. The postoperative intraocular pressure (IOP) did not change when compared with preoperative values (P > 0.05).

Conclusions

ICL V4c implantation is a safe, effective, and stable solution for high myopia. Patients will acquire high and stable postoperative optical quality. ICL V4c implantation has little influence on IOP.

Buffering zone of implantable Collamer lens sizing in V4c

Background

The purpose of this study was to identify factors related to the unexpected vault in V4c implantable collamer lens (ICL; STAAR Surgical) implantation.

Methods

V4c ICLs were implanted in 43 eyes of 43 patients for the correction of myopia. The implanted V4c ICL sizes were determined individually with our previous V4 ICL sizing nomogram based on the sulcus-to-sulcus diameter (STS), and the V4 ICL sizes were then converted to V4c ICL sizes with a size-converting table. We defined the “normal-sizing group” as having a pre-converted ICL size larger than the STS, and the “under-sizing group” as having a pre-converted ICL size smaller than the STS. Refractive outcomes, safety and parameters related to postoperative vault were compared between the two groups.

Results

The value of “actual ICL size – STS” differed significantly between the normal-sizing and under-sizing groups (p < 0.001), but postoperative vault did not differ significantly (p = 0.442). The demographics, implanted ICL characteristics, effectiveness indexes, safety indexes, and parameters related to postoperative vault did not differ significantly between the two groups (p > 0.05). Two patients in the normal-sizing group exhibited over-vaulting; these patients had shallow anterior chambers and were implanted with high-dioptric-power ICLs.

Conclusions

The achievement of acceptable vault in both normal-sizing and under-sizing groups indicates the existence of a buffering zone in V4c ICL sizing. The smaller size of V4c ICLs should be considered in patients susceptible to over-vaulting, such as those with shallow anterior chambers and high-dioptric-power ICLs.

Impacts of Implantable Collamer Lens V4c Placement on Angle Measurements Made by Optical Coherence Tomography: Two-Year Follow-up

PURPOSE

To determine iridocorneal angle changes produced after 2 years of implantable collamer lens (ICL) V4c (STAAR Surgical AG, Nidau, Switzerland) placement by Fourier-domain optical coherence tomography (FD-OCT).

DESIGN

Prospective interventional case series.

METHODS

In 54 eyes of 27 myopic subjects FD-OCT iridocorneal angle measurements were made before and 1 month, 3 months, 1 year, and 2 years after ICL implant. Trabecular-iris angle (TIA), angle opening distance 500 μm from the scleral spur (AOD₅₀₀), and iridotrabecular contact length (TICL) were compared among these time points and the nasal, temporal, and inferior quadrants.

RESULTS

Preoperative TIAs were 49.5 ± 8.7, 48.3 ± 9.6, and 49.1 ±8.6 degrees for the nasal, temporal and inferior quadrants (P < .001). Corresponding values were 29.9 ± 10.4, 28.4 ± 10.8, and 28.8 ± 9.7 degrees at 1 month and 27.3 ± 8.8, 26.8 ± 8.1, and 28.9 ± 7 degrees at 2 years of follow-up, indicating angle narrowing of 39%-45% and no further narrowing beyond 1 month in the nasal (P = .133), temporal (P = .376), and inferior (P = 1.000) quadrants. Trabecular-iris contact (TIC) was observed in 8 eyes of 8 subjects, mostly only in the temporal quadrant. Mean TICL failed to vary during follow-up (307 ± 288 μm at 3 months and 225 ± 142 μm at 2 years, P = .159).

CONCLUSIONS

In response to ICL V4c implant, considerable angle narrowing was detected at 1 month but this narrowing remained stable at 2 years. In the 8 cases of TIC, no progression of contact was observed beyond 3 months postimplant.

Posterior chamber phakic intraocular lens implantation: comparative, multicentre study in 351 eyes with low-to-moderate or high myopia

AIM

To compare the clinical outcomes of posterior chamber phakic intraocular lens implantation with a central hole (Hole Implantable Collamer Lens (ICL), STAAR Surgical) for low-to-moderate myopia and for high myopia.

METHODS

This multicentre retrospective case series comprised 351 eyes of 351 consecutive patients undergoing ICL implantation. Eyes were divided into groups based on preoperative degree of myopia: group 1; 57 eyes, manifest spherical equivalent less than -6 dioptres (D), and group 2; 294 eyes, -6 D or more. Safety, efficacy, predictability, stability and adverse events were compared preoperatively; and at 1 day, 1 week and 1, 3, 6 and 12 months postoperatively, RESULTS: Uncorrected and corrected visual acuities were -0.17±0.14 and -0.21±0.10 logMAR in group 1, and -0.16±0.09 and -0.21±0.08 logMAR in group 2, 1 year postoperatively. In groups 1 and 2, 98% and 99% of eyes were within 1.0 D of the targeted correction. Manifest refraction changes of -0.12±0.34 D (group 1) and -0.18±0.43 D (group 2) occurred from 1 day to 1 year. ICL exchanges were necessary in two eyes (0.7%) in group 2. No vision-threatening complications occurred at any time.

CONCLUSIONS

The ICL performed well for the correction of both low-to-moderate myopia and high myopia throughout the 1-year observation period. The clinical outcomes of ICL implantation for low-to-moderate myopia are essentially equivalent to those for high myopia.

Pseudophakic ametropia management with toric implantable collamer lens with a central hole (case report)

BACKGROUND

To report the clinical outcomes of correcting pseudophakic ametropia using toric implantable collamer lens with a 360 um central hole (TICL V4c).

CASE PRESENTATION

The right eye of a 22-year-old male patient developed high myopia after unilateral phacoemulsification and intraocular lens (IOL) implantation following traumatic cataract 16 years ago. The manifest refraction was -11.50 DS/-2.50 DC × 175 with an uncorrected distance visual acuity (UDVA) of 20/2000 and a corrected distance visual acuity (CDVA) of 20/20. The manifest refraction of left eye was -6.25 DS/-3.75 DC × 180 with UDVA 20/200 and CDVA 20/20. Both eyes were implanted posterior chamber TICL V4c lens. Postoperatively, the refractive errors were +1.00 DS/-0.50 DC × 50 with UDVA 20/16 and CDVA 20/16 in the right eye and +0.75 DS/-0.75 DC × 45 with UDVA 20/16 and CDVA 20/13 in the left eye, respectively. No complications were observed.

CONCLUSIONS

TICL V4c is safe, effective and predictable in managing pseudophakic ametropia.

Effects of Implantable Collamer Lens V4c Placement on Iridocorneal Angle Measurements by Fourier-Domain Optical Coherence Tomography

PURPOSE

To assess by Fourier-domain optical coherence tomography (FDOCT) changes produced in iridocorneal angle measurements in patients undergoing Visian Implantable Collamer Lens (ICL) V4c (STAAR Surgical AG) placement.

DESIGN

Prospective interventional case series.

METHODS

In 50 eyes of 25 myopic subjects consecutively scheduled for ICL implant, FDOCT (RTVue; Optovue Inc) iridocorneal angle measurements were made before and 1 and 3 months after surgery. Trabecular-iris angle (TIA) and angle opening distance 500 μm anterior to the scleral spur (AOD500) were compared among the quadrants nasal, temporal, and inferior, and correlations with ocular variables including lens vault were examined.

RESULTS

Preoperative TIA was 48.7 ± 8.7, 48.2 ± 8.7, and 48.7 ± 9.3 degrees for the nasal, temporal, and inferior quadrants, with no differences (P = 1.000). Following ICL implant, corresponding values fell to 31.2 ± 11.5, 30.0 ± 10.7, and 29.7 ± 8.1 degrees at 1 month postsurgery, indicating angle narrowing of 34%-42%, and to 30.6 ± 12.3, 30.1 ± 11.9, and 29.8 ± 12.3 degrees, respectively, at 3 months postsurgery. Angle measurements failed to vary between 1 month and 3 months postsurgery (P = .481). In 8 eyes, iridotrabecular contact attributable to surgery was observed. One month after surgery, vault measurements correlated with TIA (R = -.309; P = .048). Six variables were identified as predictors of TIA at 1 month postsurgery (R(2) = .907).

CONCLUSIONS

Although considerable angle narrowing was detected 1 month after ICL V4c implant, this narrowing remained stable at 3 months postsurgery. Factors predictive of TIA could serve to identify suitable candidates for ICL placement.

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.

Effect of Myopic Defocus on Visual Acuity after Phakic Intraocular Lens Implantation and Wavefront-guided Laser in Situ Keratomileusis

This study aimed to investigate the effect of myopic defocus on visual acuity after phakic intraocular lens (IOL) implantation and wavefront-guided laser in situ keratomileusis (wfg-LASIK). Our prospective study comprised thirty eyes undergoing posterior chamber phakic IOL implantation and 30 eyes undergoing wfg-LASIK. We randomly measured visual acuity under myopic defocus after cycloplegic and non-cycloplegic correction. We also calculated the modulation transfer function by optical simulation and estimated visual acuity from Campbell &Green's retinal threshold curve. Visual acuity in the phakic IOL group was significantly better than that in the wfg-LASIK group at myopic defocus levels of 0, -1, and -2 D (p < 0.001, p < 0.001, and p = 0.02, Mann-Whitney U-test), but not at a defocus of -3 D (p = 0.30). Similar results were also obtained in a cycloplegic condition. Decimal visual acuity values at a myopic defocus of 0, -1, -2, and -3 D by optical simulation were estimated to be 1.95, 1.21, 0.97, and 0.75 in the phakic IOL group, and 1.39, 1.11, 0.94, and 0.71 in the wfg-LASIK group, respectively. From clinical and optical viewpoints, phakic IOL implantation was superior to wfg-LASIK in terms of the postoperative visual performance, even in the presence of low to moderate myopic regression.

Clinical results of posterior chamber phakic intraocular lens implantation in eyes with low anterior chamber depth

PURPOSE

To investigate visual outcomes of Visian implantable Collamer lens (ICL) implantation in eyes with a shallow anterior chamber depth (ACD).

DESIGN

Retrospective, noncomparative, interventional case series.

METHODS

Medical charts of the patients with a low ACD of 2.8 mm or less who underwent implantable Collamer lens implantation were reviewed. To evaluate efficacy and safety, preoperative and postoperative uncorrected visual acuity, manifest refractive spherical equivalent (MRSE), endothelial cell count, intraocular pressure, angle opening distance at 500 μm from the scleral spur, trabecular-iris angle, and postoperative central vault were analyzed.

RESULTS

The mean follow-up period for 18 eyes of 10 patients was 24.67 ± 15.09 months (range, 10 to 51 months). The preoperative ACD was 2.71 ± 0.08 mm (range, 2.42 to 2.79 mm). There was no postoperative endothelial cell count reduction to less than 2000 cells/mm(2) or intraocular pressure elevation to more than 21 mm Hg. The differences between preoperative and postoperative angle opening distance at 500 μm from the scleral spur and trabecular-iris angle were statistically significant (P = .000, both). The mean postoperative central vault was 331.83 ± 181.28 μm (range, 174 to 811 μm), which was significantly less than expected (P = .000). Anterior subcapsular cataract was observed in 2 eyes (11.1%).

CONCLUSIONS

Implantable Collamer lens implantation in shallow ACD eyes exhibited good visual outcomes. Severe complications did not develop over relatively long periods. Two cases of anterior subcapsular cataract developed in older aged patients, suggesting the need for thorough preoperative warning about the risk of cataract. In addition, a postoperative vault less than expected should be taken into account when determining implantable Collamer lens size in lower ACD eyes.

Implantable collamer lens versus iris-fixed phakic intraocular lens implantation to correct myopia: a meta-analysis

This study is a meta-analysis comparing the efficacy, predictability, and safety of correcting myopia via implantation of two types of phakic intraocular lens (PIOLs): the implantable collamer lens (ICL) and iris-fixed PIOL. The Cochrane library, Pubmed, and EMBASE were searched. Study selection, data exclusion, and quality assessment were performed by two independent observers. The pooled relative risk (RR), pooled standardized mean difference (SMD), and their 95% confidence intervals (CIs) were used to compare lenses. Seven studies, involving 511 eyes, were included. The pooled SMD in postoperative uncorrected distance visual acuity (UDVA) comparing ICLs to iris-fixed PIOLs was −0.22 (95% CI, −0.58 to 0.13; P = .22). The pooled RR values of UDVA of 20/20 or better and of 20/40 or better comparing ICLs to iris-fixed PIOLs were 1.15 (95% CI, 0.89 to 1.47; P = .29) and 1.01 (95% CI, 0.95 to 1.08; P = .75), respectively. The pooled RR of loss of best spectacle-corrected visual acuity (BSCVA) and gain in BSCVA comparing ICLs to iris-fixed PIOLs were 1.20 (95% CI, 0.24 to 6.00; P = .82) and 1.14 (95% CI, 0.89 to 1.48; P = .31), respectively. The pooled RR comparing ICLs to iris-fixed PIOLs was 0.78 (95% CI, 0.29 to 2.12; P = .63) for all reported complications and 2.80 (95% CI, 1.04 to 7.52; P = .04) for severe complications. The pooled RR of achieving a result within ±0.5 D (diopter) of the intended target comparing ICLs to iris-fixed PIOLs was 1.35 (95% CI, 1.04 to 1.77; P = .03). Overall, there is no significant difference in efficacy between the two types of PIOLs or in safety, except that the ICL is associated with a greater incidence of severe complications, especially anterior subcapsular cataract, primarily in the Version 2 and Version 3 groups. However, ICL has better predictability.

Risk factors associated with night vision disturbances after phakic intraocular lens implantation

PURPOSE

To investigate the incidence and severity of night vision disturbances after implantable collamer lens surgery and to analyze the risk factors.

DESIGN

Retrospective, noncomparative study.

METHODS

Medical charts from 50 eyes of 25 patients who underwent implantable collamer lens implantation were retrospectively reviewed. The incidence and severity of night vision disturbances were evaluated using questionnaires administered 6 months after surgery. Univariate simple and multiple logistic regression analyses were used to detect risk factors associated with postoperative night vision disturbances. Potential risk factors included in the analysis were keratometric value, anterior chamber depth, postoperative residual refractive error, higher-order aberrations, preoperative and postoperative mesopic pupil size, the difference between preoperative and postoperative mesopic pupil size, the difference between mesopic pupil size and implantable collamer lens optic zone diameter, white-to-white diameter, sulcus-to-sulcus diameter, and postoperative implantable collamer lens vaulting. The power, size, optic zone diameter, and toricity of the implantable collamer lens were also included as variables.

RESULTS

The incidence of night vision disturbances was 34.0% for halos and 26.0% for glare. Halos were found to be significantly related to the difference between mesopic pupil size and implantable collamer lens optic zone diameter (P = .013), white-to-white diameter of the cornea (P = .028), and implantable collamer lens optic zone diameter (P = .030). For glare, toricity of the implantable collamer lens was revealed as a significant risk factor (P = .047).

CONCLUSIONS

Although not severe, the incidence of night vision disturbances after implantable collamer lens implantation was not negligible. Possible risk factors for night vision disturbances include implantable collamer lens optic zone diameter, the difference between mesopic pupil size and implantable collamer lens optic zone diameter, and white-to-white diameter of the cornea for causing halos, and the toricity of the implantable collamer lens for causing glare.

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.

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.

Changes in vaulting of myopic and toric implantable collamer lenses in different lighting conditions

PURPOSE

To evaluate the changes in vaulting of myopic and toric Implantable Collamer Lenses (ICLs) in different lighting conditions.

METHODS

Thirty-seven eyes of 37 patients implanted with a myopic ICL and 26 eyes of 26 patients implanted with a toric ICL were examined using Visante optical coherence tomography (OCT) in photopic (257 lux) and mesopic (2 lux) conditions. Pupil diameter and distance changes between the ICL and adjacent intraocular structures were measured.

RESULTS

The mean horizontal pupillary diameters in mesopic conditions were 5.3 ± 0.9 (SD) mm. In photopic conditions, a mean decrease of -1.8 ± 0.6 mm [95% confidence interval (95% CI) -2.0 to -1.7; p < 0.0001] was observed. The mean distances between the ICL and the crystalline lens in mesopic conditions were 0.33 ± 0.17 mm. In photopic conditions, a mean decrease of -0.04 ± 0.06 mm (95% CI -0.05 to -0.02; p < 0.0001) in the ICL-crystalline lens distance was found. There was a -0.02 ± 0.04 mm (95% CI -0.03 to -0.01; p = 0.0022) decrease in the anterior chamber depth and a 0.02 ± 0.06 mm (95% CI 0.002 to 0.032; p = 0.0275) increase in the distance between the cornea and the ICL. We found no difference in the change in vaulting between the two ICLs in different lighting conditions.

CONCLUSION

There is a decrease in the central vaulting of myopic and toric ICLs in photopic conditions. This is due to both posterior movement of the ICL and anterior protrusion of the crystalline lens.

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.

Visual and aberrometric outcomes in eyes with an angle-supported phakic intraocular lens

PURPOSE

To evaluate the postoperative changes in spherical aberration and the point-spread function (PSF) induced by the implantation of a new angle-supported phakic intraocular lens (pIOL).

SETTING

Department of Ophthalmology, St. Bassiano Hospital, Bassano del Grappa, Italy.

DESIGN

Prospective nonrandomized cohort study.

METHODS

Eyes with high myopia had implantation of an Acrysof Cachet angle-supported pIOL. Preoperative and postoperative total spherical aberration and PSF were measured using a Luneau 80 Wave+ wavefront aberrometer (high-resolution Hartmann-Shack technology) at a fixed entrance pupil scan size of 5.0 mm under pharmacologic mydriasis. Preoperative and postoperative data were analyzed and compared using the Student t test.

RESULTS

Thirty-five eyes of 18 patients were included in the statistical analysis. The Student t test for paired data (95% confidence interval) showed a statistically significant difference between preoperative data and postoperative data. The mean preoperative total spherical aberration Z(4,0) was -0.001 μm ± 0.076 (SD) preoperatively and -0.13 ± 0.11 μm postoperatively (P≤.05). The mean PSF was 0.28 ± 0.15 preoperatively and 0.34 ± 0.16 postoperatively (P<.05).

CONCLUSION

Implantation of the angle-supported pIOL in eyes with high myopia improved the quality of vision, inducing negative spherical aberration and increasing the PSF under mesopic conditions.

Visual performance after posterior chamber phakic intraocular lens implantation and wavefront-guided laser in situ keratomileusis for low to moderate myopia

PURPOSE

To compare postoperative visual function after implantable collamer lens (ICL) implantation and after wavefront-guided laser in situ keratomileusis (LASIK) in eyes with low to moderate myopia.

DESIGN

Retrospective observational case study.

PATIENTS AND METHODS

We investigated 30 eyes of 20 patients undergoing ICL implantation and 64 eyes of 38 patients undergoing wavefront-guided LASIK for the correction of low to moderate myopia (manifest spherical equivalent: -3.00 to -5.88 diopters [D]). Ocular higher-order aberrations (HOAs) and contrast sensitivity (CS) function were measured by Hartmann-Shack aberrometry and a contrast sensitivity unit before and 3 months after surgery, respectively. From the contrast sensitivity, the area under the log contrast sensitivity function was calculated.

RESULTS

For 4-mm and 6-mm pupils, the changes in ocular third-order aberrations, fourth-order aberrations, and total HOAs after ICL implantation were significantly less than those after wavefront-guided LASIK (P < .05, Mann-Whitney U test). The postoperative area under the log contrast sensitivity function was significantly increased after ICL implantation (P < .001), whereas, after wavefront-guided LASIK, it was not significantly changed (P = .11).

CONCLUSIONS

ICL implantation induces significantly fewer ocular HOAs than wavefront-guided LASIK. Moreover, CS was significantly improved after ICL implantation but unchanged after wavefront-guided LASIK in eyes with low to moderate myopia. Thus, even in the correction of low to moderate myopia, ICL implantation appears to be superior in visual performance to wavefront-guided LASIK, suggesting that it may be a viable surgical option for the treatment of such eyes.

Astigmatism correction: Laser in situ keratomileusis versus posterior chamber collagen copolymer toric phakic intraocular lens implantation

PURPOSE

To compare the stability and predictability of astigmatism correction between toric phakic intraocular lens (pIOL) implantation and laser in situ keratomileusis (LASIK).

SETTING

Nagoya Eye Clinic, Nagoya, Japan.

DESIGN

Comparative case series.

METHODS

Consecutive patients who had Implantable Collamer Lens pIOL implantation or LASIK were divided into 3 subgroups according to the amount of refractive cylinder correction (low, 0.00 to 1.25 diopters [D]; moderate, 1.50 to 2.75 D; high, ≥ 3.00 D). Manifest refraction was measured preoperatively and 1, 3, 6, and 12 months postoperatively. Based on these data, the predictability and stability of the refractive cylinder correction, error of the refractive cylinder correction, and error of the refractive cylinder correction axis were evaluated.

RESULTS

The study comprised 338 eyes (196 patients) in the toric pIOL group and 351 eyes (202 patients) in the LASIK group. In the moderate cylinder subgroup, more eyes were corrected within ± 0.50 D of the postoperative refractive cylinder in the LASIK group (132 eyes [91%]) than in the toric pIOL group (111 eyes [79%]). In the high refractive cylinder subgroup, the error of the refractive cylinder correction in the LASIK group was significantly higher than in the toric pIOL group (P=.032). The postoperative manifest refractive cylinder did not change in either group during the follow-up period.

CONCLUSIONS

The stability of the refractive cylinder after toric pIOL implantation was as high as after LASIK. Although predictability in the LASIK group was higher than in the toric pIOL group in eyes with moderate refractive cylinder, the toric pIOL group had higher predictability than the LASIK group in eyes with high refractive cylinder.

Refractive lens exchange versus phakic intraocular lenses

PURPOSE OF REVIEW

To review the evidential basis of current practice in refractive lens exchange (RLE) vs. phakic intraocular lens (pIOL).

RECENT FINDINGS

Visual outcomes after pIOLs are better than RLE. With RLE, there still remain risks of retinal detachment, cystoid macular oedema, glare, halos and posterior capsule opacification. With pIOLs, risks include pigment dispersion, cataract formation, glaucoma and inflammation. The decision to choose between either is broadly based on age and type of refractive error, and the choice follows thorough evaluation and counselling taking into consideration patient's needs and expectations.

SUMMARY

With advancing technology, newer IOL models for RLE and phakic correction are becoming available. pIOLs provide better visual outcomes for distance correction and currently do not provide near-vision correction possible with RLE.

Phakic intraocular lenses outcomes and complications: Artisan vs Visian ICL

PURPOSE

To evaluate the safety and visual outcomes of two phakic intraocular lenses (IOLs) for correction of high myopia: Artisan and Visian ICL (ICL).

PATIENTS AND METHODS

In this retrospective study, a phakic IOL was implanted in 68 highly myopic eyes of 34 patients; 42 eyes received an Artisan IOL, and 26 eyes received ICL IOL.

RESULTS

All patients completed a 1-year follow-up. The mean preoperative spherical equivalent (SEQ) was -12.89 ± 3.78, and -12.44 ± 4.15 diopters (D) for Artisan and ICL (P=0.078), respectively. The mean postoperative (1-year) uncorrected distance visual acuity was 0.39 ± 0.13 and 0.41 ± 0.15 logMAR for Artisan and ICL, respectively (P=0.268). The mean postoperative (1-year) corrected distance visual acuity was 0.36 ± 0.12 and 0.31 ± 0.12 logMAR for Artisan and ICL, respectively (P=0.128). The mean postoperative SEQ was -0.86 ± 0.5 and -0.63 ± 0.38 D for Artisan and ICL, respectively (P=0.67). Intraocular pressure change at 1 year was 0.64 ± 2.7 and 1.88 ± 0.6 mm Hg for Artisan and ICL, respectively (P=0.77).

CONCLUSION

Artisan and ICL showed equal and comparable safety, predictability, and efficacy.

Reasons for not performing keratorefractive surgery in patients seeking refractive surgery in a hospital-based cohort in "yemen"

BACKGROUND

To determine and analyze the reasons why keratorefractive surgery, laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) were not performed in patients who presented for refractive surgery consultation.

MATERIALS AND METHODS

A retrospective observational study was performed between January 2006 and December 2007 in the Yemen Magrabi Hospital. The case records of 2,091 consecutive new patients who presented for refractive surgery were reviewed. Information from the pre-operative ophthalmic examination, such as refractive error, corneal topography and visual acuity, were analyzed. The reasons for not performing LASIK and PRK in the cases that were rejected were recorded and analyzed.

RESULTS

In this cohort, 1,660 (79.4%) patients were advised to have LASIK or PRK from the 2,091 patients examined. LASIK and PRK were not advised in 431 (21%) patients. The most common reasons for not performing the surgery were high myopia >-11.00 Diopters (19%), keratoconus (18%), suboptimal central corneal thickness (15%), cataract (12%) and keratoconus suspect (forme fruste keratoconus) (10%).

CONCLUSION

Patients who requested keratorefractive surgery have a variety of problems and warrant comprehensive attention to selection criteria on the part of the surgeon. Corneal topographies and pachymetry of refractive surgery candidates need to be read cautiously. High-refractive error, keratoconus and insufficient corneal thickness were found to be the leading reasons for not performing keratorefractive surgery in this study.

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

PURPOSE

To investigate the changes in higher-order aberrations (HOAs) induced by implantation of Implantable Collamer Lenses (STAAR Surgical) and to explain them in relation to the surgical incision and optical properties.

DESIGN

Prospective, observational case study.

METHODS

This study included 56 eyes undergoing Implantable Collamer Lens insertion for myopic correction. The corneal incision size was determined according to the amount of astigmatism. HOAs were measured before surgery and 3 months after surgery in 25 eyes having small superior incision (<3.2 mm) surgery and in 31 eyes with large superior incision (3.2 to 4.5 mm) surgery. Changes in spherical aberration, coma, trefoil, and total HOAs (third to sixth order) were analyzed. Laboratory measurements of aberration profiles of Implantable Collamer Lenses with different optical powers were performed to validate clinical measurements.

RESULTS

In the small-incision group, trefoil (Z(3)(-3)) and spherical aberration changed significantly (P=.004). In the large-incision group, in addition to trefoil and spherical aberration, total HOA changed significantly (mean change, 0.13 ± 0.17; P=.001). Significant correlations were observed among the incision size, the astigmatism induced, and the trefoil induced. Induced trefoil showed a predominant pattern at the orientation of the incision meridian. Optical measurement of aberrations of the Implantable Collamer Lenses confirmed the postoperative negative spherical aberration.

CONCLUSIONS

HOA changes after Implantable Collamer Lens insertion were increased trefoil and induced negative spherical aberration. These changes may be explained by the effect of the corneal incision and the negative spherical aberration in the Implantable Collamer Lens, respectively.

Reasons for not performing LASIK in refractive surgery candidates in Yemen

PURPOSE

To determine and analyze the reasons that laser in situ keratomileusis (LASIK) was not performed in patients who requested refractive surgical correction of their refractive errors.

METHODS

A retrospective observational study was performed in Yemen Magrabi Hospital between June 2005 and October 2006; the case records of 1596 new consecutive patients who presented for refractive surgery at our refractive surgery unit were reviewed. Data on the ocular status, refractive problems, and investigations performed were analyzed. The reasons for not performing LASIK in the cases that were rejected were recorded and analyzed.

RESULTS

A total of 1191 patients (74.6%) were advised to have LASIK of the 1596 patients examined. LASIK was not advised in 405 patients (25.4%). The most common reasons for rejecting LASIK were suboptimal central corneal thickness (25.9%), high myopia >-11.00 D (17.0%), keratoconus (15.5%), cataract (11.4%), and suspicious corneal topography (forme fruste keratoconus) (9.4%).

CONCLUSIONS

Patients who request refractive surgery have a variety of problems and attention must be given to these patients. Suboptimal corneal thickness, high amount of refractive error, and keratoconus were found to be the leading causes of not performing LASIK in Yemeni patients.

Long-term changes in posterior chamber phakic intraocular collamer lens vaulting in myopic patients

OBJECTIVE

Evaluation of central and midperipheral vaulting of the posterior chamber phakic intraocular Collamer lens (ICL; Staar Surgical Inc., Monrovia, CA) in eyes with moderate to high myopia.

DESIGN

Retrospective analysis of prospectively collected data.

PARTICIPANTS

Eighty-four eyes treated with the latest ICL (V4 model) and 27 eyes treated with early ICL models were examined.

METHODS

After standardized ICL implantation, patients underwent complete ophthalmologic examinations before surgery and at 1 week, 1 month, 3 months, 6 months, and at yearly intervals thereafter. Central vaulting was measured using the Jaeger device (Haag-Streit, Bern, Switzerland). From 2006 onward, vaulting was measured additionally by optical coherence tomography (Visante OCT; Carl Zeiss Meditec, Jena, Germany). Using the Visante OCT, the crystalline lens rise and the midperipheral vaulting of the ICL were assessed.

MAIN OUTCOME MEASURES

Central vaulting after ICL implantation.

RESULTS

The mean duration of follow-up was 74.1+/-23.1 months and 96.3+/-50.2 months in eyes treated with V4 and early models, respectively. Postoperative central vaulting was 466+/-218 microm (range, 30-900 microm) in eyes treated with the V4 models and 321+/-200 microm (range, 150-900 microm) in those treated with early ICL models. From the 6-month follow-up onward, a continuous and nearly linear reduction of central vaulting was observed. At the 10-year follow-up, the mean central vaulting was reduced to 184+/-159 microm (range, 6-500 microm) and 138+/-218 microm (range, 0-820 microm) in eyes treated with V4 or early models, respectively. Eyes with total vaulting had a mean central vaulting of 407+/-202 microm (range, 180-730 microm), whereas those with midperipheral contact had a significantly lower central vaulting of 105+/-87 microm (range, 0-200 microm).

CONCLUSIONS

This study revealed consistent reduction of central vaulting over a 10-year period and provides further evidence that insufficient vaulting of the ICL is responsible for the development of anterior subcapsular cataract. A minimum central vaulting of 230 microm seems to be necessary to ensure total vaulting of the ICL. If an ICL is chosen for the correction of myopia, targeting for the greatest possible postoperative central vaulting is advised to achieve safe and complete vaulting for several years.

Toric implantable collamer lens for patients with moderate to severe myopic astigmatism: 12-month follow-up

PURPOSE

To report on the 12-month follow-up of 77 eyes with moderate to high myopic astigmatism implanted with toric implantable collamer lenses (ICLs).

METHODS

Retrospective case-note review of 77 eyes from 42 patients undergoing toric ICL placement by one surgeon. Preoperative mean spherical equivalent -2.50 dioptres (D) to -15.00 D myopia and 1.00 D to 7.00 D astigmatism.

RESULTS

At 12 months, mean manifest refractive cylinder (MRC) decreased 81% from 2.38 D to 0.44 D. MRC within 1.00 D occurred in 99% (76/77) of eyes, whereas 86% (66/77) had MRC within 0.75 D. 99% (76/77) had postoperative best-corrected visual acuity (BCVA) better than or equal to preoperative values, whereas 78% (60/77) gained up to one line BCVA and 1% (1/77) lost one line BCVA. Uncorrected binocular vision of 6/6 or better occurred in 90% (38/42) of patients compared with binocular BCVA of 6/6 or better in 67% (28/42) preoperatively. One ICL was replaced due to low vaulting. Two eyes with astigmatism of 3.25 D and 3.50 D received subsequent laser in situ keratomileusis (LASIK) to reduce residual small refractive errors. Indications for ICL were: myopia too high for LASIK (73%), cornea too thin for LASIK (44%) and contact lens intolerance (33%). Night halos were reported in 10% (8/77) of eyes at 12 months. One ICL was removed due to unrecognized preoperative glaucoma. There were no cases of cataract formation, or endophthalmitis.

CONCLUSION

This study is the largest reported series of toric ICL implantation in New Zealand. It supports the safety, efficacy and predictability of toric ICLs to treat myopic astigmatism.