Risk Benefit Analysis of Anterior Chamber Intraocular Lenses for the Correction of Myopia in Phakic Patients

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.

ZB5M Anterior Chamber and Fyodorov's Posterior Chamber Phakic Intraocular Lenses: Long-term Follow-up

PURPOSE

To compare the long-term complications of two outdated phakic intraocular lenses (PIOL) implanted in eyes with high myopia to aid development of better PIOL designs.

METHODS

Sixty-two eyes of 37 patients implanted with the ZB5M anterior chamber PIOL (anterior chamber group) and 22 eyes of 14 patients implanted with Fyodorov's posterior chamber PIOL (posterior chamber group) were examined. Complications were compared after a mean follow-up of 71.15 +/- 32.17 months (range: 24 to 145 months) in the anterior chamber group and 84.14 +/- 26.43 months (range: 24 to 132 months) in the posterior chamber group (P = .07).

RESULTS

At last follow-up, pupil ovalization was present in 32 (51.6%) eyes in the anterior chamber group and 1 (4.5%) eye in the posterior chamber group (P < .001), and cataract in 5 (8.1%) eyes in the anterior chamber group and 7 (31.8%) eyes in the posterior chamber group (P = .007). Phakic intraocular lens decentration, glaucoma, retinal detachment, corneal decomposition, and monocular diplopia were additional complications encountered in both groups, with no statistically significant difference.

CONCLUSIONS

Proper understanding of these outdated PIOLs may be helpful in developing better PIOL designs.

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.

Intraocular Pressure in Myopic Patients After Worst-Fechner Anterior Chamber Phakic Intraocular Lens Implantation

PURPOSE

To assess intraocular pressure measured with a Goldmann tonometer over a period of 1 year after implantation of a Worst-Fechner anterior chamber phakic intraocular lens to correct myopia of -7.00 D or more.

METHODS

We performed a prospective, non-masked study of 100 patients (100 myopic eyes) who had a Worst-Fechner phakic intraocular lens implanted to correct myopia of -7.00 D or greater. Central corneal Goldmann tonometry was performed before surgery and 1, 3, 6, and 12 months after surgery. The influence of different variables was assessed.

RESULTS

IOP showed a significant increase of a mean 2.1 mmHg at 3 months after surgery (P=.001). There was not a statistically significant difference between IOP before surgery and 6 months after PIOL implantation (P=.244) or 1 year after surgery (P=.845). In one eye, the lens was explanted 11 months after surgery because of the presence of ocular hypertension. No variables studied showed a statistically significant difference from before to after surgery.

CONCLUSIONS

Worst-Fechner anterior chamber phakic intraocular lens implantation led to a slight transitory increase of intraocular pressure during the first 3 months after surgery, but returned to preoperative levels by 6 months after implantation.

Implantable contact lens for high myopia

PURPOSE

To evaluate the efficacy, safety, and biocompatibility of a collagen polymer implantable contact lens (ICL) (Staar Collamer) as a posterior chamber phakic intraocular lens (IOL) to correct high myopia.

SETTING

Departments of Ophthalmology, Helsinki University Central Hospital, Helsinki, and Tampere University Hospital, Tampere, Finland.

METHODS

A Staar Collamer posterior chamber phakic IOL was implanted in 38 eyes of 22 patients with a mean age of 39 years (range 24 to 54 years). The mean preoperative myopia was -15.10 diopters (D) (range -7.75 to -29.00 D). Surgical implantation was performed through a 3.0 mm clear corneal sutureless incision using paraocular anesthesia. The patients were followed clinically up to 3 years. The mean follow-up was 13.6 months (range 6 to 24 months) for refractive data and 22.3 months (range 6 to 35 months) for complications. The possible inflammatory response to the ICL was measured using a laser flare meter in 12 eyes.

RESULTS

Postoperatively, all eyes had a significant increase in uncorrected visual acuity, allowing all but 3 patients (5 eyes) to manage most activities without spectacles. The mean spherical equivalent refraction at the last examination was -2.00 D +/- 2.48 (SD) (range +0.13 to -13.00 D), within +/-1.00 D of the targeted refraction in 31 eyes (81.6%) and within +/-0.50 D in 27 eyes (71.1%). In eyes in which the preoperative myopia was less than -18.00 D (n = 28), the achieved refraction was within +/-1.00 D of the intended refraction in 27 eyes (96.4%) and within +/-0.50 D in 24 eyes (85.7%). The refraction remained stable with a statistically insignificant change (P >.05) at each interval during the follow-up. The best corrected visual acuity (BCVA) improved by 1 or more lines in 23 of 32 eyes (71.9%) at 1 year. Two eyes (6.3%) lost 1 line of BCVA. Laser flare photometry showed normal aqueous flare values (11.71 +/- 6.61 photon counts/ms) in the 12 eyes measured at least 6 months after ICL implantation. Pupillary block glaucoma requiring surgical intervention occurred in 3 patients (7.9%). One patient (2.6%) developed cataract 1.5 years after ICL implantation; both ICLs were removed, and the refractive errors were corrected by lensectomy and implantation of low-power posterior chamber IOLs. One patient (2.6%) showed progression of dry macular degeneration at 17 months.

CONCLUSION

At 1 year, ICL implantation had good visual and refractive results with excellent biocompatibility. Long-term follow-up is required to confirm that significant complications do not occur in most patients over time.

Safety of posterior chamber phakic intraocular lenses for the correction of high myopia: anterior segment changes after posterior chamber phakic intraocular lens implantation

OBJECTIVE

To assess the safety of posterior chamber phakic intraocular lens (PCPIOL) implantation in patients with high myopia.

DESIGN

Prospective, noncomparative, interventional case series.

PARTICIPANTS

Twenty eyes of 10 patients were included.

INTERVENTION

Staar Collamer Implantable Contact Lens PCPIOLs were implanted for the correction of high myopia.

MAIN OUTCOME MEASURES

Intra- and postoperative complications were recorded. Specular microscopy, lens fluorophotometry, laser flare-meter, and ultrasound biomicroscopy were performed before surgery and at different stages of the follow-up period to evaluate endothelial cell density, crystalline lens transmittance, aqueous flare, and anatomic relations of the implanted lenses with the other structures of the anterior segment.

RESULTS

There were no intraoperative complications. One patient experienced pupillary entrapment by the lens in the immediate postoperative period, which was resolved without incident. Pigmentary dispersion or cataracts did not appear during the postoperative period. All the lenses remained correctly centered, and no patient reported night halos or glare. Anterior chamber depth showed a statistically significant reduction, between 9% and 12%. Central endothelial density was significantly decreased after surgery. The percentages of cell loss after 3, 6, 12, 18, and 24 months were 4.41%, 4.83%, 5.17%, 5.46%, and 6.57%, respectively. Aqueous flare increased by 49.19% in the first postoperative month in relation to preoperative values. Afterward, it decreased and then remained above preoperative values for the entire follow-up period (33.76% at month 3, 27.81% at month 6, 27.65% at month 12, 23.39% at month 18, and 27.27% at month 24). Crystalline lens transmittance decreased by 0.72% at month 3, by 1.44% at month 6, by 1.95% at month 12, by 2.25% at month 18, and by 2.24% at month 24. Finally, by ultrasound biomicroscopy it was observed that the PCPIOL and the crystalline lens were in contact on the peripheral level in 12 patients (60%) and in the center in another three patients (15%) during at least one checkup. In all the patients, contact between the PCPIOL and the posterior iris surface could be observed.

CONCLUSIONS

Posterior chamber phakic IOL implantation for the surgical correction of high myopia is a safe procedure with regard to immediate visual and refractive results. The short-term clinical benefit and lack of immediate surgical complications are impressive. However, the increase in flare, the endothelial cell loss, the decrease in crystalline lens transmittance, and the iris-PCPIOL and crystalline lens-PCPIOL contact are findings that suggest caution regarding the long-term safety of this lens implant.

Phakic anterior chamber lenses for the correction of myopia: a 7-year cumulative analysis of complications in 263 cases

OBJECTIVE

To perform a prospective, clinical trial to determine the potential cumulative complications of patients implanted with angle-supported phakic intraocular lenses (PIOLs) for the correction of myopia.

DESIGN

Nonrandomized, prospective, comparative trial.

PARTICIPANTS

Two hundred sixty-three eyes of 160 consecutive patients were included.

INTERVENTION

Angle-supported anterior chamber intraocular lenses were implanted into phakic eyes.

MAIN OUTCOME MEASURES

Night halos and glare were recorded. Central endothelial cell count, postoperative inflammation, applanation tonometry, cataract development, retinal detachment, and pupil ovalization were recorded by the same physician.

RESULTS

Night halos and glare were reported as significant by 20.2% at 1 year and 10% at year 7 of follow-up. This complication was significantly lower in the larger optical zone PIOL (ZSAL-4) than in the ZB5M/ZB5MF group (P < 0.05). Acute postoperative iritis was observed in 4.56% of cases. High intraocular pressure that required antiglaucoma medications appeared in 7.2% of cases. Central corneal endothelial cell density was significantly decreased at postoperative month 3 (P < 0.0001). The percentages of cell loss were 3.76% at month 3 and 1.83% at year 1, and then the percentages decreased by 1.37% more at year 2, 0.72% at year 3, 0.3% at year 4, 0.6% at year 5, 0.4% at year 6, and 0.56% at year 7. The total cumulative loss of central endothelial cells after 7 years was 8.37%. Pupil ovalization was present in 5.9% of cases, although smaller degrees of this complication were observed in another 10.3%. Retinal detachment appeared in 3% of cases. The PIOL explantation was decided in 11 cases (4.18%) because of cataract development (9 cases) and extreme pupil ovalization associated with severe glare (2 cases). The Kaplan-Meier cumulative survival analysis study showed an expected period free from complication of 86.5% for IOP elevation, 98.75% for endothelial cell count inferior to 1500 cells/mm2, 86.97% for pupil ovalization, 95.43% for retinal detachment, and 89.02% for explantation.

CONCLUSIONS

Angle-supported PIOL appeared to be well tolerated by the corneal endothelium with a low rate of other complications. Pupil ovalization seemed to be a specific problem for this type of PIOL.

Posterior Chamber Phakic Intraocular Lens for Myopia of -8 to -19 Diopters

PURPOSE

To examine the efficacy, predictability, stability, and safety of posterior chamber phakic intraocular lens (IOL) implantation in patients with extreme myopia.

METHODS

We analyzed the results of 124 eyes that received a posterior chamber hydrogel collagen plate phakic IOL (Staar Collamer Implantable Contact Lens, ICL) for the correction of their myopia. The target postoperative spherical equivalent refraction was emmetropia. Mean follow-up was 11 months (range 1 to 36 mo).

RESULTS

The mean preoperative spherical equivalent refraction was -13.38 +/- 2.23 D (range, -8.50 to -18.63 D). Mean postoperative spherical equivalent refraction at last examination was -0.78 +/- 0.87 D (range, +1.63 to -3.50 D), with 69% (86 eyes) within +/-1.00 D and 44% (55 eyes) within +/-0.50 D of emmetropia. The refraction remained stable with a statistically insignificant change (p > 0.05 at each interval) during follow-up. A gain of two or more lines of spectacle-corrected visual acuity was seen in 36% (45 eyes) at last examination. One eye (0.8%) lost two or more lines of spectacle-corrected visual acuity from a retinal detachment.

CONCLUSION

Posterior chamber phakic IOL implantation with the Staar Collamer plate lens is an effective and safe method for reducing or correcting myopia between -8 and -19 D. Gains in spectacle-corrected visual acuity were common, and results suggested good refractive stability. Improvements in phakic IOL power calculation formulas are needed to improve the predictability of refractive outcome.

Results and Complications of Laser in situ Keratomileusis by Experienced Surgeons

PURPOSE

To identify intraoperative and early postoperative adverse events and complications that may be encountered after the laser in-situ keratomileusis (LASIK) learning process.

METHODS

One hundred sixty-nine consecutive eyes of 108 patients who had LASIK by a surgeon experienced in LASIK were studied. All intraoperative and early postoperative adverse events and complications were noted. Patients were examined at 1 day and 1 to 3 months after surgery. Six baseline refractive groups were studied: high myopia with astigmatism (-10.25 to -17.50 D; 18 eyes), moderate myopia with astigmatism (-6.00 to -9.50 D; 31 eyes), low myopia with astigmatism (-0.75 to -5.87 D; 81 eyes), mixed astigmatism (-0.25 to +0.50 D; 6 eyes), low to moderate hyperopia with astigmatism (+1.00 to +3.75 D; 19 eyes), and high hyperopia with astigmatism (+4.25 to +7.37 D; 12 eyes). Seventy-eight percent (132 eyes) had a primary LASIK procedure; 22% (37 eyes) had LASIK after previous refractive surgery. Primary and secondary LASIK procedures were analyzed together. The Nidek EC-5000 or the Chiron PlanoScan excimer lasers were used.

RESULTS

The most commonly observed adverse intraoperative events were minor corneal bleeding (3%) and thin flap (1%). The most commonly observed postoperative events were punctate epithelial keratopathy (6%) and small epithelial defect 1 day after surgery (5%). The most serious complication occurred in three eyes with preoperative high hyperopia (spherical equivalent refraction greater than +4.00 D) in which corneal topographic abnormalities resulted. At last examination, mean postoperative spherical equivalent refraction was less than +1.00 D in all groups. Spectacle-corrected visual acuity was 20/20 in 70 eyes (41%) and 20/25 or better in 119 eyes (70%). Loss of spectacle-corrected visual acuity of two or more lines occurred in five eyes (3%), three of which had preoperative high hyperopia with abnormal postoperative corneal topography.

CONCLUSION

Our prospective study should help LASIK surgeons gauge their expectations of intraoperative and early postoperative complications. Surgeons should proceed cautiously when treating patients with high hyperopia, because a higher incidence of loss of spectacle-corrected visual acuity may be encountered postoperatively.

Laser in situ Keratomileusis for Myopia from -5.50 to -11.50 Diopters with Astigmatism

PURPOSE

To determine the efficacy, predictability, safety, and short-term stability of laser in situ keratomileusis (LASIK) in treating patients with high myopia and astigmatism.

METHODS

We retrospectively studied the results of our initial 119 eyes with myopia ranging from -5.50 to -11.50 D and astigmatism less than 4.00 D that underwent LASIK with the Nidek EC-5000 excimer laser. Follow-up was at 1 day, 1 month, and 3 to 6 months; follow-up was 71% (84 eyes) at the 3 to 6 month visit (average 4.5 months).

RESULTS

Of the 84 eyes with 3 to 6 months of follow-up, mean baseline spherical equivalent refraction was -8.62 +/- 1.27 D and mean cylinder was -1.84 +/- 1.02 D. Mean postoperative spherical equivalent refraction at the last examination was -0.61 +/- 0.84 D and mean cylinder was -0.39 +/- 0.38 D, with 83% (70 eyes) achieving a spherical equivalent refraction within +/-1.00 D of emmetropia, and 56% (47 eyes) within +/-0.50 D. Mean regression of spherical equivalent from 1 day to 1 month was less than -0.50 D and refractions were stable between 1 month and 3 to 6 months. An uncorrected visual acuity of 20/40 or better was noted in 84% (71 eyes) of these eyes on day 1 after surgery, in 75% (63 eyes) at 1 month, and in 77% (65 eyes) at 3 to 6 months. Twenty-two percent (18 eyes) of these eyes achieved 20/20 or better uncorrected visual acuity at 3 to 6 months; only 17% (14 eyes) had 20/20 or better spectacle-corrected visual acuity before surgery. One patient lost two or more lines of spectacle-corrected visual acuity at the last examination due to epidemic keratoconjunctivitis.

CONCLUSION

LASIK with the Nidek EC-5000 excimer laser appears to be an effective and safe means for treating patients with high myopia and astigmatism. Studies with longer follow-up will help evaluate the long-term stability of the procedure and the possibility of late complications.

Closed-System Technique for Implantation of Iris-Supported Negative-Power Intraocular Lens

BACKGROUND

The iris-supported claw lens can reversibly correct a wide range of ametropia and aniseikonia with excellent predictability and stability. However, concerns regarding its potential harm to the corneal endothelium have prevented its widespread use. Our experience with the closed-system surgical technique and the spreader device used in 180 cases between 1987 and 1993 has led us to conclude that potential complications are more likely due to the technique of implantation rather than to the properties of the lens itself.

METHOD

We conducted a prospective study of 35 eyes of 20 consecutive patients (mean age, 38 years; range, 21 to 55 years) operated on between August 1993 and August 1994. Preoperative spherical equivalent refractions ranged from -6.00 to -21.25 diopters (D) (mean, -12.50 D). Follow up was 6 months (86% of eyes) to 1 year (57% of eyes). Spectacle-corrected visual acuity and endothelial cell density were measured prior to, and 1, 6, and 12 months following lens implantation. All data were analyzed using the paired t-test.

RESULTS

Mean endothelial cell density dropped insignificantly (p > .10):by 1.22% at 1 month (n = 34), by 2.25% at 6 months (n = 27), and by 1.21% at 12 months (n = 18). Spectacle-corrected visual acuity increased significantly (p < .001): from a mean of 0.61 preoperatively to 0.77 at 1 month, 0.84 at 6 months, and 0.93 at 12 months postoperatively. At 12 months, 15 eyes (75%) had a refraction within +/-0.50 D, 19 eyes (95%) within +/-1.00 D, and 20 eyes (100%) within +/-2.00 D of emmetropia.

CONCLUSIONS

Our results suggest that the closed-system approach using the spreader device allows safe implantation of the Worst iris-supported claw lens.