Iris Claw Phakic Lens—Intermediate and Long-term Corneal Endothelial Changes

Long-term endothelial changes in phakic eyes after Artisan intraocular lens implantation to correct myopia: five-year study

PURPOSE

To evaluate long-term endothelial cell changes in eyes that had implantation of an iris-fixated phakic Artisan intraocular lens (IOL) for moderate to high myopia.

SETTING

Casa di Cura Villa Igea, Ancona, Italy.

METHODS

Forty-nine eyes of 30 patients having implantation of Artisan IOL for moderate to high myopia were prospectively examined. Preoperative specular microscopy and serial postoperative specular microscopy (Noncon Robo SP 8000, Konan Medical) were performed to evaluate endothelial cell changes over 5 years. Endothelial cell images were collected in the central region of the cornea before surgery and 4, 12, 24, 36, 48, and 60 months after surgery. The endothelial cell density (ECD), coefficient of variation, and percentage of hexagonal cells were determined.

RESULTS

Preoperatively, the mean ECD was 2616 cells/mm(2) +/- 347 (SD), the mean coefficient of variation was 39.6% +/- 4.7%, and the mean percentage of hexagonal cells was 49.2% +/- 6.7%. The mean endothelial cell loss from preoperatively was 2.3% at 4 months, 3.5% at 12 months, 4.7% at 24 months, 6.7% at 3 years, 8.3% at 4 years, and 9.0% at 5 years. Five years after surgery, the mean coefficient of variation was 35.9% +/- 6.9% (P = .1946) and the percentage of hexagonal cells was significantly higher (mean 54.7% +/- 10.3%) (P = .087).

CONCLUSIONS

Continuous endothelial cell loss was observed after surgery during a 5-year follow-up, especially during the first 2 years. A decrease in the coefficient of variation and an increase in the percentage of hexagonal cells were observed over time, reflecting the increasing stability and remodeling of the corneal endothelial cells 5 years postoperatively.

Techniques of intraocular lens suspension in the absence of capsular/zonular support

Implantation of intraocular lenses has become the standard of care in the aphakic state. Ideally, the lens is placed in the capsular bag, which affords stable fixation at a position closest to the nodal point of the eye. However, there will always be instances where this will not be possible. Congenital weakness of the lens zonules in various conditions, trauma, and surgical complications of cataract surgery are just some examples. In this article, we review the methods that have been devised to allow intraocular lens implantation in the absence of capsular or zonular support. These include anterior chamber angle and iris-fixated lenses, as well as posterior chamber iris- and scleral-sutured lenses. The various lenses are described, and the techniques involved, advantages and disadvantages, complications, and results of each method are discussed. It is hoped that this article will provide a comprehensive overview of ways to deal with a problem that can still result in a very good visual outcome for the patient. This is particularly relevant given the many recent developments and refinements of methods in implanting intraocular lenses.

Rate of Cataract Formation in 343 Highly Myopic Eyes After Implantation of Three Types of Phakic Intraocular Lenses

PURPOSE

To assess the feasibility of using phakic intraocular lenses (PIOL) to treat high myopia, and evaluate the incidence of cataract, comparing three different lens types.

METHODS

From 1989 to 2002, we implanted three different phakic intraocular lenses (PIOL) in 343 eyes of 232 patients; 231 eyes recieved an Ophtec (Worst-Fechner model, iris-claw), 89 an Adatomed (silicone posterior chamber), and 23 a Staar (posterior chamber, models V2, V3, V4). Average follow-up was 96.2 months for the Ophtec group, 31.5 months for the Adatomed group, and 19.3 months for Staar group. Eyes that subsequently developed cataract were studied for clinical evolution and had PIOL explantation and cataract extraction.

RESULTS

Nuclear cataract developed in 7 of 231 eyes (3.04 %) with an Ophtec lens. Anterior subcapsular cataract developed with the two types of posterior PIOLs (Adatomed group: 38/89 eyes, 42.69%; Staar group: 3/23 eyes, 13.04%). Anterior subcapsular cataract in the Adatomed group developed more rapidly compared to the Staar group. We explanted 7 lenses in the Ophtec group, 16 lenses in the Adatomed group, and 2 lenses in the Staar group (models V2 and V3 only). Patient age older than 40 years at implantation of PIOLs and axial length greater than 30 mm were factors significantly related to nuclear cataract formation and the Ophtec lens. However, these two factors had a weaker correlation with the posterior phakic lenses (Adatomed, Staar) for high myopia than with the Ophtec lens. Postoperative best spectacle-corrected visual acuity remained stable after explantation, phacoemulsification, and posterior chamber lens implantation.

CONCLUSIONS

Delayed cataract development and cataract type (nuclear) in patients with an Ophtec lens and the variables of patient age (>40 yr) and axial length (>30 mm) may considered prognostic factors. Other factors such as lens design, material, and placement probably influenced cataract formation in patients with the Adatomed and Staar PIOLs. The lens styles used in this study are no longer manufactured.

Implantation of a toric phakic intraocular lens to correct high corneal astigmatism in a patient with bilateral marginal corneal degeneration

We present a patient with marginal corneal degeneration and corneal astigmatism of more than 10.0 diopters (D). A toric phakic intraocular lens (IOL) of 7.0 D cylindrical power was implanted in both eyes to correct the high astigmatism. An uncorrected visual acuity of 20/40 was achieved in both eyes, and the best corrected visual acuity improved by 4 Snellen lines to 20/20 in both eyes. Refraction and visual acuity remained stable at 1.5 years postoperatively. Implantation of a toric phakic IOL can be an option to correct high corneal astigmatism even when the full corneal astigmatism cannot be treated.

Phakic intraocular lenses to correct high myopia

PURPOSE

To evaluate the feasibility and safety of using phakic intraocular lenses (IOLs) to correct high myopia by comparing 3 IOL models: Adatomed, Staar, and Artisan.

SETTING

La Fe University Hospital, Department of Ophthalmology, and the Fundación Oftalmológica del Mediterráneo, Valencia, Spain.

METHODS

In this prospective comparative study, a phakic IOL was implanted in 217 highly myopic eyes (118 patients). Fifty-nine eyes received an Adatomed IOL, 21 eyes a Staar IOL, and 137 eyes an Artisan IOL. The mean preoperative spherical equivalent was -15.39 diopters (D) +/- 2.83 (SD), -16.00 +/- 5.05 D, and -16.17 +/- 2.75 D in the Adatomed, Staar, and Artisan groups, respectively. The mean follow-up was 32.4 months (range 19 to 46 months) in the Adatomed group, 18.3 months (range 11 to 21 months) in the Staar group, and 121.4 months (range 38.4 to 154.3 months) in the Artisan group. At the follow-up examinations, intraocular pressure (IOP), IOL pigment deposits, cataract formation, and visual acuity were evaluated.

RESULTS

The best corrected and uncorrected visual acuities improved in all eyes. No significant differences in visual acuity improvement were observed with the 3 materials, although the improvement was somewhat greater in eyes with the Artisan and Staar IOLs. The difference in mean IOP between preoperatively and the last follow-up examination was 1.5 mm Hg in the Staar group, 1.3 mm Hg in the Adatomed group, and 1.7 mm Hg in the Artisan group (P =.36, P =.26, and P =.32, respectively). The incidence of pigment deposits was similar in the Adatomed and Staar groups, with deposits in 32 eyes (54.23%) and 8 eyes (38.1%), respectively. Anterior cataract formation was higher in the Adatomed group (44.06%) than in the Staar group (9.52%); nuclear cataract developed in 2 Adatomed eyes (1.46%) only.

CONCLUSIONS

There was a higher incidence of anterior subcapsular cataract formation in the Adatomed group than in the Staar group. Delayed cataract development and the cataract type in patients with Artisan IOLs indicate that age and axial length may be prognostic factors. Factors such as IOL design, material, and placement probably affect cataract formation in eyes with posterior chamber IOLs for high myopia, particularly the Adatomed IOL.

Adjustable refractive surgery: 6-mm Artisan lens plus laser in situ keratomileusis for the correction of high myopia

PURPOSE

To evaluate efficacy, predictability, stability and safety of adjustable refractive surgery (ARS) by combining a phakic intraocular lens (IOL) (Artisan lens 6-mm optical zone [OZ]) and laser in situ keratomileusis (LASIK) (6.5 mm OZ) for the correction of myopia greater than -15.00 diopters (D).

DESIGN

Noncomparative interventional case series.

PARTICIPANTS

Twenty-six eyes of 18 patients with a preoperative spherical equivalent between -16.00 and -23.00 D.

METHODS

First surgery: An 8.5/9.5-mm flap was created and a 6-mm optic iris claw phakic IOL of -15.00 D was inserted in the anterior chamber through a posterior corneal incision. The second surgery was performed once refraction and topography were stable, between 3 and 5 months later. Second surgery: LASIK enhancement (6.5-9.2 OZ); the flap was relifted, and the residual refractive error was corrected.

MAIN OUTCOME MEASURES

The main parameters in this study were uncorrected visual acuity, best-corrected visual acuity (BCVA), refraction, contrast sensitivity, endothelial cell count (ECC), and subjective response.

RESULTS

Twenty-eight months after both surgeries, 80.70% of the eyes were within 0.50 D of emmetropia and 100% within 1.0 D. Twenty-six percent of the eyes gained 3 or more lines from their preoperative BCVA, and 42% gained 2 or more lines. There was no visual loss in any eye from 6 weeks to 24 months after LASIK enhancement (second surgery) and refraction, and visual acuities remained stable. Two subjects (11%) had some subjective disturbances at night. There was a 0.61% mean loss of ECC during the first 12 months and a 0.60% loss during the next 16 months. No serious complications were observed.

CONCLUSIONS

ARS with the combination of a 6-mm optic, 15 D Artisan lens, and LASIK appears to be a safe and highly predictable method for the correction of myopia greater than -15.00 D. It is the best approach with the technology currently available.

Posterior Chamber Phakic Intraocular Lenses to Correct High Myopia: A Comparative Study Between Staar and Adatomed Models

PURPOSE

To determine the feasibility of using posterior chamber phakic intraocular lenses (PIOLs) to treat high myopia, comparing two different models, Staar and Adatomed.

METHODS

Twenty-four eyes from 12 patients were studied prospectively. A phakic Staar IOL was implanted in one eye of each patient, and the other eye received a phakic Adatomed IOL. Patients with uveitis or ocular trauma prior to ocular surgery, diabetic retinopathy, or capsular pseudoexfoliation were excluded. The mean preoperative spherical equivalent refraction was -16.00 +/- 5.05 D for the Staar group and -15.39 +/- 2.83 D for the Adatomed group. Average follow-up was 32.4 months (range, 19 to 46 mo) for the Adatomed group and 18.3 months (range, 11 to 21 mo) for the Staar group and included evaluation of intraocular pressure, intraocular lens pigment deposits, lens decentration, anterior subcapsular cataract, and visual acuity.

RESULTS

Spectacle-corrected and uncorrected visual acuity improved in all eyes in both groups. No statistically significant differences in visual acuity gain were observed with the two materials (Student t-test, P = .08 for the Staar group and P = .6 for the Adatomed group), although the gain in visual acuity was somewhat greater with the Staar PIOLs. The difference in mean intraocular pressure before surgery and at last follow-up was 1.5 mmHg for the Staar group and 2.3 mmHg for the Adatomed group (P = .36). The incidence of lens pigment deposits was the same in both groups (41.66%), with deposits in 5 of the 12 eyes in both groups. The incidence of lens decentration was higher in the Adatomed group (5/12; 41.66%) than in the Staar group (2/12; 16.7%). Anterior subcapsular cataract was higher in the Adatomed group (4/12; 33.3%) than in the Staar group (3/12; 25%).

CONCLUSIONS

There was a higher incidence of lens decentration and anterior subcapsular cataract in the Adatomed group than in the Staar group.

Multicenter study of the Artisan phakic intraocular lens

PURPOSE

To assess the Artisan intraocular lens to correct myopia in phakic eyes.

SETTING

European multicenter study sponsored by Ophtec BV, Groningen, The Netherlands.

METHODS

In this prospective multicenter clinical study, the Artisan lens was implanted in 518 eyes between September 1991 and October 1999. The power of the lenses ranged from -5.0 to -20.0 diopters (D). Follow-up examinations were performed at 6 months and 1, 2, and 3 years. Follow-up ranged from 6 months (n = 454) to 3 years (n = 249). The preoperative uncorrected visual acuity (UCVA) was not recorded but was estimated to be worse than 0.1. The preoperative mean best spectacle-corrected visual acuity (BSCVA) was 0.67 +/- 0.26 (SD). Endothelial cell counts were done at 6 months and 1, 2, and 3 years in a subgroup of 129 eyes.

RESULTS

A UCVA of 20/40 or better was observed in 76.8% of eyes regardless of the postoperative goal. A BSCVA of 20/40 or better was observed in 93.9% of eyes and remained stable throughout the follow-up. Of the eyes with extremely high myopia (>-15.0 D), 63.3% gained 2 or more lines of BSCVA; of those with moderate myopia (-5.0 to -10.0 D), 23.5% gained 2 or more lines. The mean endothelial cell density change was 4.8% at 6 months, 2.4% at 1 year, 1.7% at 2 years, and 0.7% at 3 years. The incidence of persistent adverse events at 3 years was relatively low. Secondary surgical interventions included repositioning of the lens because of poor initial placement and lens exchange because of preoperative power calculation errors. Glare and halo effects during night driving were noted and were related to large pupils in young patients.

CONCLUSION

The Artisan lens is a safe, stable, efficacious, and predictable method to correct -5.0 to -20.0 D of myopia. This study suggests that the corneal endothelial cell loss is stabilized to the physiologically normal level after 3 years.

Iris Claw Phakic Intraocular Lens for High Myopia

BACKGROUND

The implantation of a Worst-Fechner iris claw intraocular lens (IOL) is one of the surgical procedures used for the correction of high myopia. This technique reduces myopia with stable refractive results; however, its potential long-term risks have not been evaluated. We report results in 94 eyes with a minimum follow-up of 3 years.

METHODS

We studied 94 eyes of 62 patients with myopia > or = -7.00 diopters (D) who underwent Worst-Fechner IOL implantation. Lens decentration, permeability of the blood-aqueous barrier by iris angiography, and changes in corneal endothelial density were analyzed.

RESULTS

Mean follow-up time was 48.9 months (range 36 to 72 mo). Three years after surgery, 58 eyes (61%) had an uncorrected visual acuity > or = 20/40, and 77 eyes (82%) gained two or more lines of spectacle-corrected visual acuity with respect to the preoperative value; 75 eyes (79%) were within +/- 1.00 D of emmetropia and 46 eyes (48%) were within +/- 0.50 D of emmetropia. The mean endothelial cell loss was 17.9% at 5 years after surgery, while the percentage of hexagonality and the coefficient of cell variation tended toward preoperative levels. No vision threatening complications were seen.

CONCLUSIONS

The implantation of a Worst-Fechner iris claw phakic IOL reduced high myopia with a stable refractive outcome. Endothelial cell damage was within acceptable limits. The absence of major complications makes this procedure an acceptable method for correcting high myopia.

Bilateral Cataract after Phakic Posterior Chamber Top Hat-style Silicone Intraocular Lens

BACKGROUND

New strategies have been developed for surgical treatment of high myopia. Recently, implantation of minus power posterior chamber intraocular lenses (IOL) into phakic eyes has been introduced.

METHODS

We report a 37 year-old female patient who developed bilateral anterior subcapsular cataract 7 years after minus-power, top hat-style silicone posterior chamber IOL implantation in Russia. The corrected visual acuity was right eye 20/200 and left eye 20/63. Because of the high myopia and the posterior chamber IOL in her phakic eyes, biometry for IOL calculation gave contradictory results. Both posterior chamber IOLs were found to be adherent to the crystalline lenses. After posterior chamber IOL explantation and phacoemulsification, intraoperative retinoscopy was performed. With this aphakic refraction, the IOL power was calculated and implanted. The explanted posterior chamber IOLs were examined by scanning electron microscopy.

RESULTS

After bilateral operation the corrected visual acuity increased to right eye 20/32 and left eye 20/40, respectively. On scanning electron microscopy, a membranous structure of unknown origin was noted on the entire surface of the explanted posterior chamber IOLS.

CONCLUSION

There is a potential risk of cataract formation after implantation of this top hat-style silicone posterior chamber IOL. If cataract extraction in this specific situation is needed, a different approach for calculating the aphakic IOL power is necessary, such as intraoperative retinoscopy.

Iris-fixated Worst claw versus sulcus-fixated posterior chamber lenses in the absence of capsular support

PURPOSE

To evaluate visual outcomes and complications of iris-fixated intraocular lenses (IOLs) (lobster-claw) and sutured sulcus-fixated posterior chamber (PC) IOLs in primary and secondary implantation.

SETTING

Eye Department, University Hospital "La Fe", Valencia, Spain.

METHODS

This retrospective study reviewed 47 patients who had primary implantation of an iris-fixated (n = 34) or sulcus-fixated (n = 13) IOL and 54 patients who had secondary implantation of an iris-fixated (n = 41) or sulcus-fixated (n = 13) IOL.

RESULTS

Visual acuity in the primary implantation group was similar with both lens types. Overall, 54.0% had a postoperative acuity of 20/40 or better. In eyes without pre-existing pathology, 60.0% with an iris-fixated IOL and 54.6% with a sutured PC IOL had this level of postoperative acuity (P = .768). In the secondary implantation group, the percentage of patients with a postoperative visual acuity of 20/40 or better was significantly higher in iris-fixated IOL eyes (78.0%) than in sulcus-fixated PC IOL eyes (46.2%) (P < .05). In eyes without pre-existing pathology, the difference was maintained. No intraoperative complications directly associated with iris-fixated lens implantation occurred. The incidence of postoperative complications common to either IOL type in primary and secondary implantation did not differ significantly. The incidence of retinal complications was higher in eyes that had primary implantation of either lens type, although the differences between both lenses in either primary or secondary implantation were not significant.

CONCLUSION

The good visual outcomes and low incidence of intraoperative and postoperative complications in eyes with iris-fixated IOLs indicate that these lenses should be considered an alternative to sutured PC IOLs in eyes in which capsular support is inadequate or absent.