Collagen copolymer toric posterior chamber phakic intraocular lens for myopic astigmatism: One-year follow-up

Analysis of surgically induced astigmatism of the anterior, posterior, and total cornea after implantable collamer lens implantation: a comparative study between temporal and superior clear corneal incisions

BACKGROUND

To comparatively analyze the surgically induced astigmatism (SIA) of the anterior, posterior, and total corneas of eyes undertaking implantable collamer lens (ICL) implantation with temporal or superior corneal incisions.

METHODS

One hundred and nine eyes of 109 patients who received ICL implantation were recruited: 40 eyes had temporal incisions and 69 eyes had superior incisions. Total corneal refractive power (TCRP); simulated keratometry of the anterior (Sim-KAnt) and posterior (Sim-KPost) corneal curvature; and astigmatism of the anterior (CAAnt), posterior (CAPost), and total (CATCRP) cornea were recorded through a Pentacam preoperatively and 3 months postoperatively. The SIA of the anterior, posterior, and total cornea were also compared between the two groups.

RESULTS

There were no significant intergroup differences for TCRP, Sim-KAnt, Sim-KPost, CAAnt, CAPost, or CATCRP, preoperatively. However, values of CAAnt, CAPost, and CATCRP with temporal incision were significantly higher than those parameters with superior incision postoperatively. All of the SIA of the anterior, posterior, and total cornea were significantly lower for temporal incision than those with a superior incision (p < 0.001, p = 0.006 and p = 0.001 respectively). Meanwhile, the superior incisions created against-the-rule (ATR) astigmatism, and temporal incisions always induce with-the-rule (WTR) astigmatism in total cornea.

CONCLUSIONS

A superior incision may be suitable for correcting WTR astigmatism, while a temporal incision for correcting ATR astigmatism when using a non-toric ICL. Meanwhile, temporal incision could be a better choice with little preoperative astigmatism or that preoperative astigmatism would be corrected with toric ICLs.

TRIAL REGISTRATION

Registration number: ChiCTR2100051739. Prospectively registered: 01 October 2021.

Efficacy and Safety After Toric Posterior Chamber Implantable Collamer Lens and Toric Iris-Fixated Foldable Phakic Intraocular Lens for Myopic Astigmatism

PURPOSE

To compare visual, refractive, and safety outcomes of toric posterior chamber Implantable Collamer Lens (T-ICL) (STAAR Surgical) and toric iris-fixated foldable phakic intraocular lens (IOL) (T-Artiflex; Ophtec BV) implantation for the correction of myopic astigmatism.

METHODS

This retrospective cohort study included 312 eyes of 312 patients who had phakic IOL implantation for myopic astigmatism. Two groups were defined: 205 eyes that underwent T-ICL implantation and 107 eyes that underwent T-Artiflex implantation. Safety, efficacy, and predictability outcomes were evaluated preoperatively and at 12 months postoperatively. Refractive and corneal astigmatic vector analysis were performed using the Alpins method.

RESULTS

One year postoperatively, uncorrected distance visual acuity was 0.05 ± 0.18 (T-ICL) and 0.10 ± 0.16 (T-Artiflex) logMAR, with efficacy indexes of 1.16 ± 0.27 and 1.05 ± 0.31, respectively (P < .001). Safety indexes were 1.28 ± 0.30 and 1.21 ± 0.31, respectively (P = .04). Spherical equivalent was within ±0.50 diopters (D) of emmetropia in 165 (80.5%) and 88 (82.2%) eyes, respectively. Refractive astigmatic analysis showed an index of success of 0.28 ± 0.33 (T-ICL) and 0.31 ± 0.26 (T-Artiflex) (P = .07). Surgically induced corneal astigmatism was 0.48 ± 0.74 and 0.81 ± 0.61 D, respectively (P < .001). Mean endothelial loss was 1.11% and 2.05%, respectively (P = .42). Six (2.9%) eyes in the T-ICL group and 1 (0.9%) eye in the T-Artiflex group had phakic IOL repositioning due to significant misalignment. No vision-threatening complications occurred.

CONCLUSIONS

Both the T-ICL and T-Artiflex groups showed high visual and refractive efficacy with a good safety profile for the correction of myopic astigmatism. T-ICL implantation demonstrated significantly better efficacy and safety indexes after 12 months. Vector analysis showed similar refractive astigmatic correction in both groups, but T-Artiflex implantation revealed higher surgically induced corneal astigmatism. [J Refract Surg. 2022;38(6):339-347.].

Comparison of magnitude and summated vector mean of surgically induced astigmatism vector according to incision site after phakic intraocular lens implantation

Background

To compare the arithmetic mean (M-SIA) and the summated vector mean of surgically induced astigmatism (SVM-SIA) according to the incision site after phakic intraocular lens (Visian implantable collamer lens (ICL), STAAR Surgical) implantation.

Methods

This study comprised 121 eyes of 121 consecutive patients undergoing ICL surgery through a 3.0-mm temporal or superior clear corneal incision. The magnitude and the axis of corneal astigmatism preoperatively and 3 months postoperatively were measured using an automated keratometer. The M-SIA and the SVM-SIA were determined according to the incision site.

Results

The magnitude of corneal astigmatism significantly increased from 1.23 ± 0.59 D preoperatively to 1.46 ± 0.72 D postoperatively in the temporal incision group (Wilcoxon signed-rank test, P < 0.001), but it significantly decreased from 1.09 ± 0.36 D preoperatively to 0.86 ± 0.41 D postoperatively in the superior incision group (P < 0.001). The M-SIA was 0.48 ± 0.30 D, and the SVM-SIA was 0.23 ± 0.52 D at a meridian of 82° in the temporal incision group. The M-SIA was 0.57 ± 0.30 D, and the SVM-SIA was 0.47 ± 0.45 D at a meridian of 1° in the superior incision group.

Conclusions

ICL implantation induces the M-SIA by approximately 0.5 D, but the SVM-SIA decreased to 50% and 80% of the M-SIA in magnitude through temporal and superior incisions, respectively. The direction of the SVM-SIA showed a tendency toward corneal flattening to the incisional site. It should be noted that the M-SIA is somewhat different from the SVM-SIA according to the incision site.

Trial registration University Hospital Medical Information Network Clinical Trial Registry (000044269)

Controversy and Consideration of Refractive Surgery in Patients with Heritable Disorders of Connective Tissue

Heritable Disorders of Connective Tissue (HDCTs) are syndromes that disrupt connective tissue integrity. They include Osteogenesis Imperfecta (OI), Ehlers Danlos Syndrome (EDS), Marfan Syndrome (MFS), Loeys-Dietz Syndrome (LDS), Epidermolysis Bullosa (EB), Stickler Syndrome (STL), Wagner Syndrome, and Pseudoxanthoma Elasticum (PXE). Because many patients with HDCTs have ocular symptoms, commonly myopia, they will often present to the clinic seeking refractive surgery. Currently, corrective measures are limited, as the FDA contraindicates laser-assisted in-situ keratomileusis (LASIK) in EDS and discourages the procedure in OI and MFS due to a theoretically increased risk of post-LASIK ectasia, poor wound healing, poor refractive predictability, underlying keratoconus, and globe rupture. While these disorders present with a wide range of ocular manifestations that are associated with an increased risk of post-LASIK complications (e.g., thinned corneas, ocular fragility, keratoconus, glaucoma, ectopia lentis, retinal detachment, angioid streaks, and ocular surface disease), their occurrence and severity are highly variable among patients. Therefore, an HDCT diagnosis should not warrant an immediate disqualification for refractive surgery. Patients with minimal ocular manifestations can consider LASIK. In contrast, those with preoperative signs of corneal thinning and ocular fragility may find the combination of collagen cross-linking (CXL) with either photorefractive keratotomy (PRK), small incision lenticule extraction (SMILE) or a phakic intraocular lens (pIOL) implant to be more suitable options. However, evidence of refractive surgery performed on patients with HDCTs is limited, and surgeons must fully inform patients of the unknown risks and complications before proceeding. This paper serves as a guideline for future studies to evaluate refractive surgery outcomes in patients with HDCTs.

One-year follow-up of a new posterior chamber toric phakic intraocular lens implantation for moderate-to-high myopic astigmatism

PURPOSE

To investigate refractive and visual outcomes as well as rotational stability following implantation of Eyecryl phakic toric intraocular lens (pIOL) for moderate-to-high myopic astigmatism.

METHODS

The efficacy, safety, predictability, stability, and adverse events of Eyecryl toric pIOL were evaluated in patients with spherical refraction from - 4.50 to - 18.50 diopters (D) and cylindrical refraction from - 0.50 to - 5.50 D.

RESULTS

This study included 60 eyes of 31 patients. The mean manifest refraction spherical equivalent (MRSE) dropped from - 10.45 ± 2.74 D preoperatively to - 0.34 ± 0.51 D and - 0.40 ± 0.56 D at 6 and 12 months postoperatively, respectively. There was an 81% decrease in astigmatism after surgery. The safety and efficacy of indices were 1.36 ± 0.43 and 1.20 ± 0 .32. At the final follow-up, the rate of eyes within ± 1.00 D and ± 0.50 D of the desired MRSE were 85% and 68.33%, respectively. Vision-threatening complications were not observed during the follow-up.

CONCLUSIONS

The implantation of pIOL was effective, safe, and predictable in patients with moderate-to-high myopic astigmatism during 1-year follow-up.

Phakic intraocular lens: Getting the right size

Phakic intraocular lenses (IOL) are a boon for patients who want spectacle independence but are unable to get refractive correction through laser platforms due to high refractive error or certain corneal contraindications. Phakic IOL's (PIOL) have their own set of complications and challenges, the most important being getting the sizing right. This paper attempts to solve the problem of accurate sizing of PIOL's. Parameters needed for calculating the ideal size of PIOL's have been studied in a step by step manner using all possible tools depending upon the availability and preference of the surgeon. The pros and cons of using a particular tool for measurements have been highlighted along with illustrative case examples to help surgeons who are starting PIOL implantation surgery.

Vector analysis of small incision lenticule extraction and toric implantable collamer lens implantation for astigmatism correction

OBJECTIVES

To compare the efficacy of small incision lenticule extraction (SMILE) and toric implantable collamer lens (TICL) implantation for myopic astigmatism correction using vector analysis.

METHODS

In this retrospective study, 171 eyes of 171 patients with cylinder ⩾1.0 diopters (D) were recruited, with 97 eyes underwent SMILE and 74 eyes underwent TICL implantation. Preoperative and 3-months postoperative visual and refractive results were examined. The astigmatism correction, graded by the degree of preoperative cylinder was compared between two groups using vector analysis.

RESULTS

At 3-months postoperatively, the residual cylinder was -0.10 ± 0.21 D in the SMILE group and -0.30 ± 0.32 D in the TCL group (p < 0.05). Furthermore, 98% and 85% of eyes had the cylinder within ±0.5 D in the SMILE and TICL group, respectively. The vector analysis revealed similar target induced astigmatism vector in two groups. However, the difference vector, magnitude of error, angle of error, and index of success were significantly higher (0.30 ± 0.32 D, -0.19 ± 0.25, -2° ± 4.35°, and 0.16 ± 0.17 D, respectively) in the TICL group than the values in the SMILE group (0.10 ± 0.21 D, -0.05 ± 0.20, -0.03° ± 2.13°, and 0.05 ± 0.12, respectively), regardless of the degree of preoperative cylinder (all p < 0.05). For preoperative cylinder < 2.0 D, surgically induced astigmatism vector and correction index in the SMILE group were higher than those in the TICL group (p < 0.05).

CONCLUSION

Both SMILE and TICL implantation are effective techniques for myopic astigmatism correction. However, the accuracy of correction in the magnitude and axis of astigmatism with SMILE was better than that achieved with TICL implantation.

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.

Implantable collamer lens with central hole: 3-year follow-up

Purpose

To evaluate the long-term predictability, stability, safety, and efficacy of the V4c Visian implantable collamer lens (ICL) with central hole to correct myopia.

Patients and methods

One hundred and eighty-four eyes of 92 patients were evaluated during 3 years after implantation of the V4c ICL. The refraction, uncorrected distance visual acuity, best-corrected distance visual acuity, IOP, endothelial cell count, vault, and adverse effects were evaluated every 12 months during the whole follow-up.

Results

The mean spherical equivalent dropped from -8.30±2.98 D preoperatively to −0.37±0.47 D at 36 months post-surgery, with 91.8% eyes being within ±1.00 D of emmetropia. With respect to the astigmatic components J0 and J45, 98.4% and 99.5% of eyes, respectively, were within ±0.50 D of the desired refraction. At 36 months, 78.8% of eyes had no change in the Snellen lines of best-corrected distance visual acuity, while 8.7% gained one line and 6.5% gained two or more lines; mean safety and efficacy indexes were 1.03 and 0.90, respectively. Mean endothelial cell count was 2,742±340 cells/mm² before and 2,663±366 cells/mm² at 36 months post-surgery. Mean IOP reduced from 13.7±1.9 mmHg preoperatively to 12.8±1.7 mmHg at 36 months post-surgery. Mean vault varied from 409±196 µm at 12 months to 349±165 µm at 36 months.

Conclusion

The visual and refractive outcomes were very good and highly stable throughout the follow-up period, indicating that this ICL model may be predictable, stable, safe, and effective to correct myopia in the long term.

Rotational Stability and Visual Outcomes of V4c Toric Phakic Intraocular Lenses

PURPOSE

To investigate the clinical outcomes and rotational stability following implantation of V4c toric implantable collamer lenses (ICLs) (STAAR Surgical Company, Monrovia, CA) and to analyze the factors that influence rotational stability.

METHODS

In this prospective observational case series, the authors analyzed the visual outcomes and rotational stability in 52 eyes of 52 patients immediately and 3 and 6 months after implantation. Postoperative rotation was defined as the angle between the adjusted axis and alignment axis. Central vaulting of the ICL was measured in a non-accommodative state using Visante optical coherence tomography (Carl Zeiss Meditec, Jena, Germany). Vector analysis of refractive astigmatism was performed. Regression analysis was used to investigate the association between the degree of rotation 6 months postoperatively and the associated variables.

RESULTS

The mean efficacy index and safety index 6 months postoperatively were 1.35 ± 0.19 and 1.38 ± 0.22, respectively. In vector analysis, the magnitude of error was -0.20 diopters (D), indicating slight undercorrection. Absolute degree of rotation was 2.81° ± 1.87° immediately after the operation and 3.75° ± 2.92° and 3.87° ± 3.07° at 3 and 6 months postoperatively, respectively (P = .009). Bonferroni-adjusted post-hoc comparison showed that the absolute degree of rotation immediately after the operation was significantly smaller than that after 3 (P = .043) and 6 (P = .023) months, with barely any change after 3 months. No explanatory variable relevant to the absolute degree of rotation was discovered.

CONCLUSIONS

The V4c toric ICL is predictable, safe, and effective in correcting low and high levels of astigmatism, showing relatively good postoperative rotational stability. [J Refract Surg. 2018;34(7):489-496.].

Continuous intracorneal ring implantation for treatment of myopic astigmatism

We report a case of myopic astigmatism, not eligible for laser vision correction and with an anterior chamber depth below that recommended for application of phakic implantable collamer lens. In this case, the only refractive surgery option that remained for the patient was intracorneal ring implantation. The aim of the current presentation was to document the clinical and refractive outcomes after continuous intracorneal ring implantation in both eyes in this patient with myopic astigmatism. The results presented were collected during a 4-year follow-up period. Surgery was performed at Lasik specialty center, Baghdad, Iraq, in 2013.

Comparison between toric and spherical phakic intraocular lenses combined with astigmatic keratotomy for high myopic astigmatism

BACKGROUND

To compare the outcomes of a toric phakic intraocular lens (PIOL) and a spherical PIOL combined with astigmatic keratotomy (AK) for the correction of high myopic astigmatism.

METHODS

This study enrolled patients with high myopic astigmatism, including 30 eyes (22 patients) that received a toric PIOL implantation (TICL group), and 32 eyes (24 patients) that received combined AK and a spherical PIOL implantation (AK+ ICL group). The outcomes were compared between the two groups before surgery, and at the following time points after surgery: 1 week, 1, 3, 6 months, and 1, 2 years.

RESULTS

Preoperatively, the mean manifest spherical equivalent (SE) was -14.14 ± 2.12 D in the TICL group and -14.83 ± 2.79 D in the AK + ICL group (P = 0.28), and the mean manifest refractive cylinder, -2.87 ± 1.09 D and -2.58 ± 0.85 D, respectively (P = 0.28). Two years postoperatively, the mean safety index was 1.53 ± 0.55 in the TICL group and 1.60 ± 0.70 in the AK + ICL group (P = 1.00), and the mean efficacy index, 1.18 ± 0.45 and 1.38 ± 0.52, respectively (P = 0.86). The mean manifest refractive cylinder correction was 1.94 ± 1.07 D in the TICL group and 1.39 ± 0.71 D in the AK + ICL group (P = 0.02). The mean changes in SE and refractive cylinder from 1 week to 2 years were less than 0.50 D in both groups.

CONCLUSIONS

Both TICL implantation and AK + ICL implantation are a good alternative for correction of astigmatism in addition to high myopia. TICL implantation has better predictability in correction of high myopic astigmatism.

TRIAL REGISTRATION

NCT03202485.

Comparison of Visian toric collamer lens and toric acrylic intraocular lens implantation for the treatment of myopia with astigmatism

Purpose

To compare the efficacy and outcome of phakic toric implantable collamer lens (TICL) and refractive clear lens extraction with AcrySof Toric intraocular lens (TIOL) implantation for the treatment of myopic astigmatism.

Patients and methods

This study assessed eyes with myopic astigmatism >−1 D and ≤−4 D with a spherical equivalent >10 D or <10 D if the patients were unsuitable for corneal refractive surgery. These eyes were divided into group A, in which Visian Toric ICL™ Phakic TICL was implanted, and group B, which involved clear lens extraction with implantation of an AcrySof IQ toric SN60T3-9™ IOL. The outcome and complications were evaluated.

Results

This study enrolled 63 eyes of 38 patients with a follow-up period of at least 6 months. The mean postoperative spherical equivalent was −0.19±0.31 D in group A and −0.21±0.28 D in group B (P=0.69). The mean postoperative cylinder value was −0.46±0.53 D in group A and −0.32±0.41 D in group B (P=0.35). Postoperative cylinder was <1 D in 76.47% and 79.31% of eyes in groups A and B, respectively. The mean endothelial cell count was reduced by 4.32% in group A and by 5.32% in group B (P=0.003). The mean postoperative intraocular pressure increased insignificantly in group A (P=0.22) and reduced significantly in group B (P=0.004). The complication rate was 11.76% in group A and 6.90% in group B.

Conclusion

Both procedures showed predictable results and good visual results. However, the loss of accommodation and risk of retinal complications in the TIOL group suggest that the use of TICL for myopic astigmatism is a better choice in younger patients.

Long-Term Comparison of Posterior Chamber Phakic Intraocular Lens With and Without a Central Hole (Hole ICL and Conventional ICL) Implantation for Moderate to High Myopia and Myopic Astigmatism: Consort-Compliant Article

The study shows a promising next-generation surgical option for the correction of moderate to high ametropia. Hole implantable collamer lens (ICL), STAAR Surgical, is a posterior chamber phakic intraocular lens with a central artificial hole. As yet, however, no long-term comparison of the clinical results of the implantation of ICLs with and without such a hole has hitherto been conducted. A prospective, randomized, controlled trial was carried out in order to compare the long-term clinical outcomes of the implantation, in such eyes, of ICLs with and without a central artificial hole.Examinations were conducted of the 64 eyes of 32 consecutive patients with spherical equivalents of -7.53 ± 2.39 diopters (D) (mean ± standard deviation) in whom implantation of a Hole ICL was performed in 1 eye, and that of a conventional ICL was carried out in the other, by randomized assignment. Before 1, 3, and 6 months, and 1, 3, and 5 years after surgery, the safety, efficacy, predictability, stability, intraocular pressure, endothelial cell density, and adverse events of the 2 surgical techniques were assessed and compared over time.The measurements of LogMAR uncorrected and corrected distance visual acuity 5 years postoperatively were -0.17 ± 0.14 and -0.24 ± 0.08 in the Hole ICL group, and -0.16 ± 0.10 and -0.25 ± 0.08 in the conventional ICL group. In these 2 groups, 96% and 100% of eyes, respectively, were within 1.0 D of the targeted correction 5 years postoperatively. Manifest refraction changed by -0.17 ± 0.41 D and -0.10 ± 0.26 D occurred in from 1 month to 5 years in the Hole and conventional ICL groups, respectively. Only 1 eye (3.1%), which was in the conventional ICL group, developed an asymptomatic anterior subcapsular cataract.Both Hole and conventional ICLs corrected of ametropia successfully throughout the 5-year observation period. It appears likely that the presence of the central hole does not significantly affect these visual and refractive outcomes.

TRIAL REGISTRATION

UMIN000018771.

Posterior chamber collagen copolymer phakic intraocular lens with a central hole to correct myopia: One-year follow-up

PURPOSE

To assess the predictability, stability, efficacy, and safety of a newly developed posterior chamber phakic intraocular lens (pIOL) (model V4c Visian Implantable Collamer Lens) to correct moderate to high myopia.

SETTING

Fernández-Vega Ophthalmological Institute, Oviedo, Spain.

DESIGN

Prospective case series.

METHODS

This study evaluated eyes that had implantation of the new pIOL model with a central hole for myopia correction. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, intraocular pressure (IOP), endothelial cell density, pIOL vault, and adverse events were evaluated over 12 months.

RESULTS

The study comprised 147 eyes of 80 patients. Preoperatively, the mean spherical equivalent (SE) was -8.80 diopters (D) ± 2.60 (SD). At 12 months, the mean SE was -0.14 ± 0.26 D, with 93.9% of eyes within ±0.50 D of the target and 100% of eyes within ±1.00 D. The mean UDVA and CDVA were 0.028 ± 0.055 logMAR and 0.003 ± 0.013 logMAR, respectively. The efficacy and safety indices were 1.00 and 1.04, respectively. All eyes had unchanged CDVA or gained 1 or more lines during the follow-up. The IOP remained stable over time; no eye developed anterior subcapsular cataract. Twelve months postoperatively, the mean vault was 405.5 ± 184.7 μm (range 100 to 980 μm), and the mean endothelial cell loss was 1.7%.

CONCLUSION

The good refractive and visual acuity outcomes and the highly stable IOP values obtained over 12 months support the use of the new pIOL model with a central hole for the correction of moderate to high myopia.

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.

Prevalence of cataract after collagen copolymer phakic intraocular lens implantation for myopia, hyperopia, and astigmatism

PURPOSE

To evaluate the prevalence of cataract after Implantable Collamer Lens phakic intraocular lens (pIOL) implantation with different models at different ages and for different refractive powers.

SETTING

Fernández-Vega Ophthalmological Institute, Oviedo, Spain.

DESIGN

Retrospective nonrandomized clinical study.

METHODS

The pIOL (models V4, V4b, or V4c) was implanted in all cases.

RESULTS

The study included 3420 eyes (1898 patients). The mean patient age at surgery was 31.2 years ± 6.4 (SD) (range 18 to 50 years) and the mean spherical refractive error, -7.27 ± 5.24 diopters (D) (range -26.5 to 12.5 D). Twenty-one eyes (0.61%) of 15 patients had pIOL explantation (all model V4) because cataract developed. The mean age of the patients who had explantation was 39.43 ± 4.57 years; 7 were younger than 40 years, and 8 were 40 years or older. The mean spherical equivalent was -10.1 ± 5.41 D; 3 eyes had a pIOL power less than -10.50 D, 4 eyes between -10.50 D and -13.50 D, and 14 higher than -13.50 D. The mean time between pIOL implantation and cataract surgery was 4.2 ± 1.8 years. No eye with implantation of the latest models (V4b and V4c) developed cataract. The mean vault distance in eyes that developed cataracts was 103 ± 69 μm.

CONCLUSIONS

The incidence of cataract was low after pIOL implantation at the 6-year follow-up. The rate of cataract was higher in older patients and in those with high refractive errors.

FINANCIAL DISCLOSURE

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

Prevention and management of collagen copolymer phakic intraocular lens exchange: causes and surgical techniques

PURPOSE

To analyze causes leading to explantation and exchange of Implantable Collamer Lens phakic intraocular lenses (pIOLs) and examine the surgical techniques of pIOL exchange.

SETTING

Wuhan Aier Eye Hospital, Wuhan, China.

DESIGN

Retrospective analysis of prospectively collected data.

METHODS

Different techniques were used to explant the pIOLs based on the amount of vaulting. Preoperative and postoperative data were collected to evaluate possible causes leading to pIOL exchange and the safety of pIOL exchange.

RESULTS

Of 616 myopic eyes with previous pIOL implantation, 16 eyes of 15 patients having pIOL exchange were reviewed. Eight surgeries (50%) were performed because of low vaulting (≤100 μm) and another 8 (50%) because of too high vaulting (≥1000 μm). The causes leading to low vaulting included increased crystalline lens thickness (≥4.0 mm), low anterior chamber depth (ACD) (<3.1 mm), and a too-small pIOL (<12.0 mm). The high vaulting was primarily the result of oversized white-to-white (WTW) measurements with Scheimpflug pachymetry (Pentacam) or the use of a digital caliper by an unskilled examiner and of ciliary body cysts. Six months after pIOL exchange, the vaulting ranged from 162 to 715 μm. No anterior subcapsular cataracts or other complications occurred during the observation period.

CONCLUSIONS

The main causes of abnormal vaulting and subsequent pIOL exchange included a thick crystalline lens, low ACD, too-small pIOL, WTW measurement error, and ciliary body cysts. Phakic IOL explantations were individually designed based on the vaulting to achieve proper safety and efficacy.

FINANCIAL DISCLOSURE

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

Evaluation of the toric implantable collamer lens for simultaneous treatment of myopia and astigmatism

Myopic astigmatism is a prevalent condition that can be treated with spectacles, contact lenses, or laser refractive surgery. However, these treatment options have functional limitations at higher levels of refractive error. The toric implantable collamer lens is designed to treat a broad range of refractive error, generally up to -18 diopters with +1 to +6 diopters of astigmatism. Approval for a more limited treatment range of up to 15 diopters of myopia with +1 to +4 diopters of astigmatism is being sought in the US, where this device has not yet received marketing approval. Surgical correction of high-myopic astigmatism can be life-altering and allow people to participate in activities that were not previously feasible because of visual limitations. The toric implantable collamer lens is implanted behind the iris and in front of the natural crystalline lens. With earlier lens designs, it was necessary to create an iridectomy or iridotomy to prevent pupillary block. The newest toric implantable collamer lens model has a small central hole that is not visually noticeable. This eliminates the need to create a hole in the iris, thereby enhancing the safety of the procedure.

Visual quality comparison of conventional and Hole-Visian implantable collamer lens at different degrees of decentering

PURPOSE

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

METHODS

An adaptive optics visual simulator (crx1, Imagine Eyes, Orsay, France) was used to simulate the -3, -6 and -12 dioptres (D) conventional and Hole ICLs in three conditions: centred and decentred 0.3 and 0.6 mm. Visual acuity (VA) at high-contrast, medium-contrast and low-contrast and contrast sensitivity (CS) were measured in 15 observers for 3 and 4.5 mm pupils.

RESULTS

No statistically significant differences in VA and CS were found between conventional and Hole ICLs for any ICL powers and pupil sizes evaluated (p>0.05). Regarding the effect of the ICL decentration on visual performance, we did not find statistically significant differences in VA and CS between centred, 0.3 and 0.6 mm decentred (p>0.05). Moreover, the ICL decentration affected the same manner on the conventional and Hole ICLs.

CONCLUSIONS

The outcomes showed that conventional and Hole ICLs provided good and comparable visual performance for all powers and pupil sizes evaluated. Besides, ICL decentering affects the same manner both ICL models evaluated. The ICL decentering did not have any effect on the visual performance.

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.

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.

Comparison of optical quality and intraocular scattering after posterior chamber phakic intraocular lens with and without a central hole (Hole ICL and Conventional ICL) implantation using the double-pass instrument

Purpose

To objectively compare the optical quality and the intraocular scattering after implantation of the posterior chamber phakic implantable collamer lens (Visian ICL™, STAAR Surgical) with and without a central artificial hole for moderate to high ametropia.

Methods

This retrospective study comprised 28 eyes of 28 consecutive patients undergoing Hole ICL implantation (mean age ± standard deviation, 30.3±5.8 years), and 24 age-matched eyes of 24 patients undergoing conventional ICL implantation (age, 30.4±6.1 years). We quantitatively assessed the postoperative values of MTF cutoff frequency, Strehl ratio, objective scattering index (OSI), and OQAS values (OVs), using an Optical Quality Analysis System™. We compared these postoperative variables between the two groups.

Results

The mean MTF cutoff frequency, Strehl ratio, OSI, OV100%, OV 20%, and OV9%, were 26.21±8.32 cycles/degree, 0.16±0.04, 1.16±0.57, 0.87±0.28, 0.80±0.35, and 0.80±0.33, respectively, 3 months after Hole ICL implantation. We found no significant differences in the MTF cutoff frequency (Mann Whitney U test, p = 0.59), the Strehl ratio (p = 0.82), the OSI (p = 0.63), or the OVs at contrasts of 100% (p = 0.58), 20% (p = 0.40), and 9% (p = 0.87), between the two groups.

Conclusions

Both Hole ICL and conventional ICL implantation provides an excellent optical performance including intraocular scattering. Newly developed Hole ICL implantation appears to be essentially equivalent in the optical quality variables to conventional ICL implantation, suggesting that the presence of the central artificial hole does not significantly affect the optical quality and the intraocular scattering after surgery.

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.

Three-year follow-up of posterior chamber toric phakic intraocular lens implantation for moderate to high myopic astigmatism

PURPOSE

To assess the 3-year clinical outcomes of toric phakic intraocular lens (Visian ICL™; STAAR Surgical) implantation for moderate to high myopic astigmatism.

METHODS

This retrospective study evaluated fifty eyes of 28 patients who underwent toric ICL implantation for the correction of moderate to high myopic astigmatism and who regularly returned for postoperative examination. Before, and 1, 3, and 6 months after, and 1, 2, and 3 years after surgery, we assessed the safety, efficacy, predictability, stability, and adverse events of the surgery in eyes undergoing toric ICL implantation.

RESULTS

The logarithm of the minimal angle of resolution (LogMAR) uncorrected visual acuity and LogMAR best spectacle-corrected visual acuity were -0.10 (corresponding to Snellen equivalents 20/16) ± 0.16 and -0.20 (corresponding to 20/12.5) ± 0.07, 3 years postoperatively, respectively. The safety and efficacy indices were 1.16 ± 0.20 and 0.94 ± 0.28. At 3 year, 82% and 98% of the eyes were within 0.5 and 1.0 D, respectively, of the targeted correction. Manifest refraction changes of -0.15 ± 0.31 D occurred from 1 month to 3 year. No vision-threatening complications occurred during the observation period.

CONCLUSIONS

On the basis of the clinical results of this study, toric ICL implantation was good in all measures of safety, efficacy, predictability, and stability for the correction of moderate to high myopic astigmatism throughout a 3-year observation period.

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.

Toric implantable collamer lens for moderate to high myopic astigmatism: 3-year follow-up

BACKGROUND

To evaluate the 3-year clinical outcomes after toric implantable collamer lens (ICL) implantation for the management of moderate to high myopic astigmatism.

METHODS

Thirty-four eyes of 20 patients who underwent toric ICL implantation were reviewed. All eyes completed 3-year follow-up. Uncorrected (UDVA) and corrected (CDVA) distance LogMAR visual acuities, refraction, endothelial cell density (ECD), and surgical complications were evaluated. Vectorial analysis of astigmatic correction was also done.

RESULTS

A significant improvement in UDVA, CDVA, manifest spherical and cylindrical refraction was observed at 1 week and remained stable after 3 years. Twenty-six eyes (76.5%) gained lines of CDVA, and two eyes (5.9%) showed a loss of 1 line of CDVA. The spherical equivalent (SE) was within ±0.50 D of emmetropia in 18 eyes (52.9%) and within ±1.00 D in 28 eyes (82.4%). Differences between target-induced astigmatism (TIA) and surgically-induced astigmatism (SIA) were statistically significant (p < 0.01), and a trend to undercorrection of the refractive astigmatism was present after 3 years. The magnitude of flattening effect (FE) was found to be significantly lower than the magnitude of TIA (p < 0.01). The magnitude of the torque vector was always positive, with a value below 0.50 D in all cases. No vision-threatening complications were observed during the follow-up.

CONCLUSION

Toric ICL implantation is an effective and safe surgical option that provides a relatively predictable and stable refractive correction of myopic astigmatism. Further improvements are needed to minimize the degree of undercorrection.

Comparison of visual and refractive results of Toric Implantable Collamer Lens with bioptics for myopic astigmatism

PURPOSE

To compare visual and refractive results of Toric Implantable Collamer Lens (TICL) and bioptics (ICL plus excimer corneal surgery) to treat myopic astigmatism.

METHODS

Eighty-one eyes underwent TICL implantation and 83 eyes were treated with bioptics (corneal ablation was performed between 1.5 and 6 months after ICL implantation). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, adverse events, safety, and efficacy were evaluated 12 months postoperatively.

RESULTS

At 12 months postoperatively, the mean spherical equivalent was -0.15 ± 0.36 diopters (D) in the TICL group and -0.08 ± 0.26 D in the bioptics group (p = 0.099). Sixty-six (81.5 %) and 78 (94.0 %) eyes were within ±0.50 D for TICL and bioptics groups, respectively. The mean Snellen UDVA was not statistically different between both procedures (p = 0.909); 53 (65.4 %) and 54 (65.1 %) eyes achieved at least 20/25 or better in TICL and bioptics groups, respectively. No eye had lost more than two lines of CDVA, and 32.1 % of eyes (26/81) in the TICL group and 57.8 % of eyes (48/83) in the bioptics group had better postoperative UDVA than preoperative CDVA (p < 0.001). Safety was not statistically different between groups (p = 0.464) while efficacy was significantly higher in the bioptics group (p = 0.000). Two eyes with a TICL were treated to correct TICL decentration.

CONCLUSIONS

Bioptics showed slightly better outcomes in some clinical measures such as uncorrected visual acuity, efficacy, and refractive predictability. TICL implantation shows reliable results similar to bioptics. A single procedure with TICL implantation might be preferred, eliminating the inherent risks of laser treatments and the risks of a second surgical procedure.

Toric implantable collamer lens for high myopic astigmatism in keratoconic patients after six months

BACKGROUND

The aim was to evaluate the safety, efficacy, stability and predictability of posterior chamber collagen copolymer phakic intraocular lens (pIOL) implantation to correct myopia and myopic astigmatism associated with keratoconus.

METHODS

The unaided vision and visual acuity, refraction and adverse events were measured in 22 keratoconic eyes of 14 patients after using an implantable collamer lens (ICL) (STAAR Surgical Inc.) to correct refractive error. The outcome was evaluated over six months.

RESULTS

The mean pre-operative spherical equivalent (SE) and cylinder changed from -4.98 ± 2.63 DS and -2.77 ± 0.99 DC to -0.33 ± 0.51 DS and -1.23 ± 0.65 DC, respectively at the end of six months. Before the surgery the mean Snellen decimal visual acuity was 0.63 ± 0.20. The mean unaided vision and visual acuity changed to 0.76 ± 0.23 and 0.85 ± 0.21, respectively at the end of six months. The mean safety and efficacy indices were 1.40 ± 0.32 and 1.24 ± 0.34, respectively. No eye lost a line of visual acuity and 17 eyes (77.3 per cent) gained one or more lines. Fifteen eyes (68.2 per cent) were within 0.50 D and 20 (90.9 per cent) were within 1.00 D of the desired spherical equivalent refraction. There was a change in manifest refraction of 0.09 ± 0.21 (ranging from -0.25 to +0.75) from one week to six months after the surgery.

CONCLUSION

The clinical outcomes of the current study demonstrate the safety, efficacy and predictability of toric implantable collamer lens in the correction of myopia and myopic astigmatism associated with keratoconus. The patients' refractions achieved early stability and remained stable during the course of the study.

Long-term evaluation of the central vault after phakic Collamer® lens (ICL) implantation using OCT

PURPOSE

The aim of this work is to evaluate the changes in the central vault after using implantable Collamer® lenses (ICL) to correct myopia.

METHODS

This cohort study included 133 eyes; mean spherical equivalent -9.47 ± 3.71 diopters (D) (range: -2.75 to -22.25 D) who underwent ICL V4 implantation. Besides a complete ophthalmologic examination, the central vaulting was measured with Visante OCT and evaluated between different periods of follow-up (1 week, 1, 3, and 6 months, and yearly postoperatively). Post-operative time ranged from 6 to 73 months.

RESULTS

Within the first 6 months, the mean central vaulting dropped from 510 ± 238 μm (range 100 to 940 μm) to 439 ± 231 μm (range 90 to 910) a significant decrease by 71 ± 58 μm (range -170 to 30 μm) (p = 0.028) with a trend to a lower reduction after this period. After 36 month from ICL implantation, this variation tends to be smaller with the majority of the eyes having a mean decrease smaller than 2 μm per month. Initial vault (Spearman Rho = -0.237, p = 0.006) was the factor more significantly associated with decrease in vault; eyes presenting a reduction in vault >100 μm had an average initial vault that was 141 μm and 184 μm higher than eyes with no change or with increase in vault over time, respectively.

CONCLUSIONS

This study shows a continuous reduction of central vault over time. The reduction is highest during the first 6 months and tends to be lower and slow down over time. The decrease of vaulting was more pronounced in eyes with larger initial vaulting.

Central vault after phakic intraocular lens implantation: correlation with anterior chamber depth, white-to-white distance, spherical equivalent, and patient age

PURPOSE

To compare the central postoperative vault of a phakic intraocular lens (pIOL) to correct myopia, myopic astigmatism, and hyperopia and identify ocular and lens parameters that might predict the vault amount.

SETTING

Fernández-Vega Ophthalmological Institute, Oviedo, Spain.

DESIGN

Cohort study.

METHODS

Three months after implantation of Implantable Collamer Lens pIOLs to correct myopia, hyperopia, and myopic astigmatism, central vault was measured using optical coherence tomography. Patients were divided into groups according to the preoperative anterior chamber depth (ACD) to compare the effects of ACD, white-to-white (WTW) distance, and lens diameter on postoperative pIOL vault.

RESULTS

Hyperopic pIOLs had statistically significantly lower vault followed by myopic pIOLs and toric pIOLs, which had a higher mean value and narrower range (260 to 860 μm). Measured vaults had a positive correlation with preoperative ACD (r = .32, P<.001) and WTW (r = .29, P<.001) and a negative correlation with preoperative spherical equivalent (SE) (r = -0.21, P<.001) and patient age (r = -0.12, P=.025). Eyes with a vault of 250 μm or less had a shallower ACD than eyes with a vault between 250 μm and 750 μm (mean difference -0.11 mm; P=.012) and those with a vault greater than 750 μm (mean difference -0.25 mm; P<.001).

CONCLUSIONS

Central vaulting was lower in hyperopic eyes. Current nomograms for pIOL diameter selection based on ACD and WTW might yield ideal vault and may have to be adjusted for older patients, shallower ACD, lower WTW, and lower SE.

Implantable collamer posterior chamber intraocular lenses: a review of potential complications

PURPOSE

To review the peer-reviewed literature reporting postoperative complications of the most recent models of Visian Implantable Collamer posterior chamber intraocular lenses (ICL, STAAR Surgical Co).

METHODS

A literature search of the PubMed database was performed to identify all articles related to ICL complications. Articles were obtained and reviewed to identify those that reported complications using the latest ICL designs.

RESULTS

Cataract was the major postoperative complication reported: 136 (5.2%) in 2592 eyes. Of those, 43.4% (n=59) were reported within 1 year, 15.4% (n=21) between 1 and 3 years, and 35.3% (n=48) ≥ 3 years after ICL implantation. Twenty-one (15.4%) cataracts were reported as surgically induced, 46 (33.8%) eyes had poor vault (<200 μm), and cataract surgery was carried out in 27.9% (n=38) of eyes. Early acute intraocular pressure increase was also reported to be relatively frequent, whereas acute pupillary block was less frequent and mostly resolved with additional iridotomies. A total of 42 ICLs were explanted due to cataract and IOP. Reported endothelial cell loss varied from 9.9% at 2 years to 3.7% 4 years postoperatively. This loss was reported to be more pronounced within the first 1 to 2 years, with stability or lower progression after that time.

CONCLUSIONS

The majority of reported complications after ICL implantation are cataract formation. The improvements in lens geometry and more accurate nomograms applied to the selection of the lens to be implanted, in addition to the surgeon's learning curve, might be factors in the decreased occurrence of postoperative complications reported currently.

Toric phakic implantable collamer lens for correction of astigmatism: 1-year outcomes

Purpose:

The purpose of this study was to assess predictability, efficacy, safety and stability in patients who received a toric implantable collamer lens to correct moderate to high myopic astigmatism.

Methods:

Forty-three eyes of 23 patients underwent implantation of a toric implantable collamer lens (STAAR Surgical Inc) for astigmatism correction. Mean spherical refraction was −4. 98 ± 3.49 diopters (D) (range: 0 to −13 D), and mean cylinder was −2.62 ± 0.97 D (range: −1.00 to −5.00 D). Main outcomes measures evaluated during a 12-month follow-up included uncorrected visual acuity (UCVA), refraction, best-corrected visual acuity (BCVA), vault, and adverse events.

Results:

At 12 months the mean Snellen decimal UCVA was 0.87 ± 0.27 and mean BCVA was 0.94 ± 0.21, with an efficacy index of 1.05. More than 60% of the eyes gained ≥1 line of BCVA (17 eyes, safety index of 1.14). The treatment was highly predictable for spherical equivalent (r² = 0.99) and astigmatic components: J₀ (r² = 0.99) and J₄₅ (r² = 0.90). The mean spherical equivalent dropped from −7.29 ± 3.4 D to −0.17 ± 0.40 D at 12 months. Of the attempted spherical equivalent, 76.7% of the eyes were within ±0.50 D and 97.7% eyes were within ±1.00 D, respectively. For J₀ and J₄₅, 97.7% and 83.7% were within ±0.50 D, respectively.

Conclusion:

The results of the present study support the safety, efficacy, and predictability of toric implantable collamer lens implantation to treat moderate to high myopic astigmatism.

Collagen copolymer toric posterior chamber phakic intraocular lens in eyes with keratoconus

PURPOSE

To assess the safety, efficacy, stability, and predictability of collagen copolymer toric phakic intraocular lens (pIOL) implantation to correct myopia and astigmatism in eyes with keratoconus.

SETTING

Fernández-Vega Ophthalmological Institute, Oviedo, Spain.

METHODS

This prospective study comprised keratoconic eyes that had implantation of a toric Intraocular Collamer Lens. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, and postoperative complications were evaluated 1, 3, 6, and 12 months postoperatively.

RESULTS

Preoperatively, the mean spherical equivalent in the 30 eyes (21 patients) was -5.38 diopters (D) +/- 3.26 (SD) (range -13.50 to -0.63 D) and the mean cylinder, -3.48 +/- 1.24 D (range -1.75 to -6.00 D). At 12 months, 86.7% of the eyes were within +/-0.50 D of the attempted refraction and all eyes were within +/-1.00 D. For the astigmatic components J0 and J45, 83.3% of eyes and 86.7% of eyes, respectively, were within +/-0.50 D. The mean Snellen UDVA was 0.81 +/- 0.20 and the mean CDVA, 0.83 +/- 0.18; CDVA was 20/40 or better in 29 eyes 96.7% of eyes and 20/25 or better in 22 eyes (73.3%). No eyes lost more than 2 lines of CDVA; 29 eyes (96.7%) maintained or gained 1 or more lines. The efficacy index was 1.07 and the safety index, 1.16. There were no complications or adverse events.

CONCLUSIONS

The results confirm that toric ICL implantation is a predictable, effective procedure to correct ametropia in eyes with keratoconus. Predictability and stability were achieved early and remained fairly stable up to 12 months.