The STAAR posterior chamber phakic intraocular lens

Outcome of posterior chamber phakic intraocular lens procedure to correct myopia

PURPOSE

To assess the safety and efficacy of the implantable contact lens (ICL™) to treat myopia.

DESIGN

Clinical, retrospective, single center, non-randomized case series.

PARTICIPANTS

Sixty-nine eyes of 46 patients with myopia ranging from -3.00 to 25.00 D were included in this study.

INTERVENTION

Implantation of the ICL™.

MAIN OUTCOME MEASURES

Uncorrected Visual Acuity (UCVA), refraction, best spectacle corrected visual acuity (BSCVA), adverse events, operative and postoperative complications, subjective assessment and symptoms.

RESULTS

The mean follow-up was 12.35 ± 6.13 (SD) months (range, 6 months-32 months). At the last visit, 49.20% of eyes had 20/20 or better UCVA compared to preoperative 20/20 or better BSCVA of 31.9% of eyes; 69.23% of eyes had postoperative UCVA better than or equal to preoperative BSCVA. The mean manifest refractive cylinder was 1.93 ± 1.21 D at baseline and 1.00 ± 0.92 D postoperatively. The mean manifest refraction spherical equivalent (MRSE) was -11.70 ± 4.24 D preoperatively and -0.69 ± 1.13 D postoperatively. A total of 69.8% of eyes were within ±0.5 D of the predicted MRSE; 84.1% were within ±1.0 D, and 88.90% were within ±2.0 D. BSCVA of 20/20 or better was achieved in 64.6% of eyes postoperatively, compared to 31.9% preoperatively. Mean improvement in BSCVA was 1line. One eye (1.5%) lost ⩾2 lines of BSCVA at the last visit, whereas 20% of eyes improved by ⩾2 lines. A total of 56.92% of cases gained ⩾1 line of BSCVA and 4.62% of cases lost ⩾1 line. Four ICL lenses were removed without significant loss of BSCVA, and 2 eyes with clinically significant lens opacities were observed. Four eyes (5.8%) developed a pupillary block the first day postoperatively. One eye (1.4%) developed a hypotony and AC shallowing.

CONCLUSION

Implantation of ICL for the correction of myopia was a safe procedure with good visual and refractive results from the early postoperative period to 1 year. Long-term follow-up is required to confirm the long-term safety of this implant.

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.

Vaulting of myopic and toric Implantable Collamer Lenses during accommodation measured with Visante optical coherence tomography

PURPOSE

To study changes in vaulting of myopic and toric Implantable Collamer Lenses (ICLs) version 4 during accommodation with Visante optical coherence tomography (OCT), and analyze the relationship between vaulting and anterior subcapsular opacification.

DESIGN

Cross-sectional study.

PARTICIPANTS

Seventy-seven eyes of 77 myopic patients were examined after implantation with an ICL (48 myopic, 29 toric). The median follow-up time was 63 months (range, 10-84).

METHODS

The distance between the posterior ICL surface and the anterior surface of the crystalline lens was measured in the nonaccommodative state and during accommodation with Visante OCT. The lenses were examined for opacification using slit-lamp microscopy.

MAIN OUTCOME MEASURES

The distance between the ICL and the anterior surface of the crystalline lens.

RESULTS

At baseline, the mean distance between the ICL and the crystalline lens was 0.31+/-0.19 mm and during accommodation 0.31+/-0.26 mm; the difference did not reach significance (P = 0.77). The distance at baseline was significantly (P = 0.01) less in older patients and significantly (P = 0.04) greater in patients with a toric ICL. Contact was observed at baseline or during accommodation in 12 eyes; there was a significantly lower incidence of contact in eyes implanted with a toric ICL (P = 0.03). Anterior subcapsular opacification developed in 10 eyes, in 5 of these the ICL touched the crystalline lens.

CONCLUSIONS

Anterior subcapsular opacification developed in 13.0% of eyes. We found no difference in vaulting of the ICL at baseline and during accommodation. There was contact between the ICL and the crystalline lens in 15.6% of the eyes. The association between anterior subcapsular opacification and contact was significant (P = 0.004).

Outcome of simultaneous phakic implantable contact lens removal with cataract extraction and pseudophakic intraocular lens implantation

PURPOSE

To assess the outcome of simultaneous implantable contact lens (ICL) removal and cataract extraction with pseudophakic intraocular lens (IOL) implantation.

SETTING

CODET Aris Vision Institute, Tijuana, Mexico.

METHODS

This retrospective noncomparative interventional case series evaluated 14 eyes of 12 patients with ICL implantations who developed a cataract and simultaneously had ICL removal and cataract extraction with IOL implantation. The follow-up time was at least 6 months (range 6 to 24 months). Visual acuity (logMAR), manifest refraction, intraocular pressure, and adverse events were recorded.

RESULTS

Of the 12 patients (14 eyes), 10 patients (12 eyes) had ICL surgery to correct high myopia and 2 patients (2 eyes), to correct hyperopia. The mean uncorrected visual acuity after ICL implantation (before cataract development), before cataract surgery, and after cataract surgery were 0.48 +/- 0.32, 0.83 +/- 0.34, and 0.40 +/- 0.27, respectively. The mean best corrected visual acuity (BCVA) before ICL implantation, after ICL implantation, and after cataract surgery were 0.31 +/- 0.21, 0.28 +/- 0.19, and 0.27 +/- 0.21, respectively. The mean final manifest spherical equivalent was 0.30 diopters (D) +/- 1.07 (SD) (range +2.38 to 2.0 D). Ten eyes (71.4%) were within +/-1.0 D of the calculated target. One eye had a tear in the posterior capsule with vitreous loss during cataract surgery. No other intraoperative, perioperative, or postoperative complications were observed. No loss of BCVA was recorded at the last postoperative visit.

CONCLUSIONS

Lens opacities and cataract formation are a potential complication of ICL surgery. The removal of the ICL and the cataract with IOL implantation was found to be safe, with predictable refractive results.

Phakic Intraocular Lenses

An analytical review of the data available in the field of phakic intraocular lens implantation was conducted. Particular attention was paid to the more critical issues of intraocular lens sizing and safety guidelines. A comprehensive, competitive analysis of different implantation sites, intraocular lens model designs, and safety guidelines has been included. Specialized biometry techniques, such as very high frequency ultrasound and Scheimpflug imaging, have been reviewed, and a critical review of commercial claims regarding intraocular lens technologies has been included. Clinical studies of phakic intraocular lenses demonstrate increasing promise for the correction of refractive errors not amenable to mainstream excimer laser refractive surgery. The main issues currently revolve around adequate lens design (VHF ultrasound study suggests that custom-design and sizing may be the most effective and safest approach for every phakic IOL model), because these devices will be required to remain physiologically inert and anatomically compatible with internal ocular structures and relations for several decades. The possibility of safe removing or exchanging the IOL should remain a feasible option over time. It is of utmost importance that we continue to critically evaluate current encouraging short-term outcomes, which are being extrapolated to the longer term by ongoing high resolution imaging and monitoring of the anatomical and functional relations of implanted phakic IOLs.

Long-term results of implantation of phakic posterior chamber intraocular lenses

PURPOSE

To study the incidence and progression of lens opacification after implantation of phakic posterior chamber intraocular lenses for myopia and its correlation with vaulting and endothelial cell density (ECD).

SETTING

Department of Ophthalmology, University of Vienna Medical School, Vienna, Austria.

METHODS

An implantable contact lens (ICL V4, Staar Surgical Inc.) was inserted in 76 myopic eyes. Patients were prospectively followed preoperatively and at 1, 3, 6, 12, 24, and 36 months. The uncorrected visual acuity and best corrected visual acuity (BCVA) were determined. Vaulting was measured optically with a Jaeger II pachymeter, and the crystalline lens was examined at the slitlamp for the presence and characteristics of opacification. Endothelial cell morphometry was performed by specular microscopy, and the ECD was calculated. Eyes in which lens opacification developed were followed for at least 12 months to determine the degree and course of visual impairment.

RESULTS

Lens opacification occurred in 11 eyes (14.5%). Opacification was correlated with intraoperative trauma to the crystalline lens, age older than 50 years, and decreased ECD values throughout the observation period. Vaulting of the ICL did not correlate with the risk for lens opacification. After onset of lens opacification, 6 eyes (55%) had a stable BCVA within +/-0.5 lines and 5 eyes had progressive opacification, losing between 3.5 lines and 0.5 lines (mean 1.8 lines +/- 1.1 [SD]). Three eyes (3.9%) in the progressive group had a 1- to 2-line loss of BCVA over preoperative values and subsequently had cataract surgery.

CONCLUSIONS

Risk factors for lens opacification after implantation of the model V4 ICL included intraoperative trauma to the crystalline lens and older age. Decreased ECD in eyes with opacification suggests ongoing inflammation as a cause. Patients younger than 45 years may have a significantly lower incidence of opacification.

Implantable contact lens for moderate to high myopia: relationship of vaulting to cataract formation

PURPOSE

To study cataract formation in eyes with an implantable contact lens (ICL) used for moderate to high myopia.

SETTING

University Eye Hospital, Lausanne, Switzerland.

METHODS

An ICL (model V3 or V4, Staar Surgical AG) was implanted in 75 eyes. Three months after surgery and again at the last follow-up examination, the transparency of the crystalline lens was assessed on transilluminated photographs and the vaulting of the ICL over the crystalline lens was evaluated. Central vaulting was measured precisely on digitized photographs taken with a 75 SL Zeiss slitlamp camera, while peripheral vaulting was estimated on photographs obtained with a Scheimpflug camera. The minimum follow-up was 12 months; the mean was 21.8 months.

RESULTS

At the last follow-up, 20 of the 75 eyes (27%) had an ICL-induced anterior subcapsular cataract (ASCC). The number of cataracts increased with the duration of the follow-up. Cataracts developed more commonly in older patients than in younger patients. All 20 cataracts occurred when the central vaulting was equal to or less than 0.09 mm. In 26 eyes with the same range of vaulting (among which 11 had no vaulting), the lenses were clear at the last visit. The 20 patients with cataract and the 26 patients with clear lenses matched in age and duration of follow-up but not in myopia. No touch between the ICL and the crystalline lens was encountered when the central vaulting was equal to or greater than 0.15 mm. Vaulting showed a slight decrease over time. No statistically significant difference in vaulting was found between models V3 and V4.

CONCLUSION

Central and/or peripheral contact between the ICL and the crystalline lens may be responsible for the high incidence of ASCC formation in this study. Central vaulting greater than 0.09 mm appears to protect the crystalline lens from cataract formation. However, we recommend aiming for higher central vaulting (0.15 mm) to avoid contact between the ICL and the crystalline lens. This should be attainable by implanting longer ICLs.

Phakic intraocular lenses

Since Zaldivar's review of phakic intraocular lenses in these pages in 2000 [1**], further reports of experience with this technology have emerged. Their relative advantages and disadvantages over competing technologies are becoming clearer. Clinical trials, including Food & Drug Administration (FDA) trials, have shown predictability, stability, and efficacy. Safety of these implants over the long term remains a concern, but in some situations, at least, phakic intraocular lenses are becoming the refractive correction of choice. This brief review looks at the most recent data to emerge regarding phakic intraocular lenses.