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Artisan iris-claw phakic intraocular lens followed by laser in situ keratomileusis for high hyperopia

Muñoz, Gonzalo MD, PhD; Alió, Jorge L. MD, PhD; Montés-Micó, Robert OD, MPhil; Albarrán-Diego, César OD; Belda, José I. MD, PhD

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Journal of Cataract & Refractive Surgery: February 2005 - Volume 31 - Issue 2 - p 308-317
doi: 10.1016/j.jcrs.2004.05.056
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The surgical treatment of high hyperopia represents a challenge in refractive surgery. Corneal refractive procedures including laser in situ keratomileusis (LASIK), photorefractive keratectomy, and laser thermokeratoplasty are relatively safe and effective for the treatment of low hyperopia but do not achieve optimum results in the case of hyperopia greater than 5.0 diopters (D) because of unpredictability, regression, poor quality of vision, and significant loss of spectacle-corrected visual acuity.1–3 Clear lens extraction (CLE) with intraocular lens (IOL) implantation in patients with high hyperopia provides rapid, predictable, and stable visual rehabilitation, but the loss of accommodation limits its use in the young population.4,5 Phakic IOLs offer advantages such as reversibility, precision, wide range of correction, stability, and preservation of accommodation.6–10 However, limited data about the possible effects of phakic IOLs on the corneal endothelium in the long term are available.10,11 Moreover, complications such as endophthalmitis, cataract, pupillary block, glaucoma, corneal degeneration, IOL dislocation, and retinal detachment have been reported after phakic IOL implantation.12–16

Some authors have proposed the combination of corneal and intraocular surgical techniques to achieve optimum results in the case of high ametropia, creating a different approach called bioptics or adjustable refractive surgery.17,18 In bioptics, IOL implantation is followed by LASIK to obtain the advantages of both procedures. With the phakic IOL, the greatest amount of ametropia is corrected, while the ocular structures remain nearly unchanged. Months later, the residual refraction is corrected using LASIK, with the precision of the lamellar corneal procedure for low ametropia. However, combining intraocular and corneal surgical procedures might compound the complications of both techniques.

This study evaluated the safety, efficacy, predictability, and stability of the combination of iris-fixated phakic IOL implantation followed by LASIK (bioptics) for the correction of high hyperopia, with special attention to the effects on the corneal endothelium. To our knowledge, the combined use of bioptics in the treatment of high hyperopia has not been reported. We are not aware of a study that has investigated the safety of LASIK performed in hyperopic eyes containing an iris-fixated phakic IOL.

Patients and Methods

Patients

This prospective study included patients older than 21 years of age with primary hyperopia or hyperopic astigmatism, a spherical equivalent (SE) greater than +5.0 diopters (D), a stable refractive history for more than 1 year, a normal ophthalmologic examination, and unsatisfactory correction with glasses or contact lenses. Refractive surgical treatment was considered only if alternative nonsurgical methods of correction did not meet the needs of the patient for medical, professional, or personal reasons. Details of phakic IOL implantation and follow-up and potential complications of intraocular surgery with an iris-fixated phakic IOL and LASIK were discussed, together with alternative refractive procedures and their respective benefits and risks. The patients were specifically informed about the lack of studies of the use of LASIK in eyes containing an iris-fixated phakic IOL for high hyperopia. Written informed consent was obtained from all patients before surgery in accordance with the Declaration of Helsinki, and the study was approved by the local ethics committee.

Exclusion criteria were anterior chamber depth less than 2.8 mm, best corrected visual acuity (BCVA) worse than 0.25, pupil diameter larger than 5.0 mm under dim illumination, previous corneal or intraocular surgery, anterior segment pathology, evidence of developing cataract, history of uveitis or posterior synechias, keratoconus, corneal dystrophy, central endothelial cell count less than 2250 cells/mm2, glaucoma or intraocular pressure (IOP) greater than 21 mm Hg, existing retinal or optic disc pathology, pregnancy, diabetes mellitus, steroid or immunosuppressive treatment, and connective tissue diseases.

Methods

Preoperative and postoperative evaluation included uncorrected visual acuity (UCVA), BCVA, manifest and cycloplegic refractions, slitlamp biomicroscopy, gonioscopy, applanation tonometry, fundus examination, ultrasonic pachymetry, B-scan biometry, keratometry, and corneal topography. Cycloplegic refraction was estimated 20 minutes after instillation of cyclopentolate 1% (Cicloplegico). After phakic IOL surgery and after LASIK, all patients completed a follow-up protocol with examinations at 1 day, 1 week, 1 and 3 months, and then every 3 months as necessary. All eyes had a follow-up of at least 12 months after the second surgery (LASIK).

Data for analysis were extracted from chart review; each eye of the same patient was analyzed separately. A corneal endothelial study of the central cornea was performed using a Konan SP5500 contact endothelial cell meter. Endothelial cell density (ECD), percentage of hexagonality, and coefficient of variation were documented following a published protocol.10 The endothelial study was done before phakic IOL implantation, immediately before LASIK, and at the end point of the follow-up period 12 months after LASIK. Endothelial cell density before phakic IOL surgery was used in each case as the reference to calculate endothelial cell loss (ECL) according to the following formula: Symbol.

Symbol
Symbol

The same surgeon (G.M.) performed all procedures consecutively at the Instituto Oftalmológico de Alicante between January 2001 and March 2002. The hyperopic model of the Artisan phakic iris-claw IOL (Ophtec BV) consists of a concave−convex optic of poly(methyl methacrylate) with an overall length of 8.5 mm, a diameter of 5.0 mm, and a central thickness of 0.93 mm. The power of the IOL was calculated based on the van der Heijde formula,19 which uses central anterior chamber depth (ACD), keratometric power, and cycloplegic refraction. Since astigmatism (preexisting plus or surgically induced minus) was corrected by LASIK, only the spherical part of the refraction was considered, with a minus sign in front of the cylinder. Anterior chamber depth was measured with an ultrasonic biometer (Ocuscan). Keratometric power was estimated from the tangential map of corneal topography (EyeSys Technologies) measured at the 3.0 mm diameter zone.

The technique for implantation of the Artisan phakic IOL for hyperopia has been described.9 Briefly, the procedure was performed under peribulbar anesthesia; a Honan balloon (Lebanon Corp.) was used for at least 20 minutes before surgery. The Artisan phakic IOL was inserted through a 6.0 mm clear corneal incision, which was then sutured with a 3-bite, running, 10-0 nylon suture. Postoperative care included instillation of cyclopentolate 1% immediately after surgery and then 1 drop per day for 5 days to prevent development of posterior synechias. Tobramycin and dexamethasone eyedrops (TobraDex) 6 times a day for 15 days and diclofenac drops (Voltaren) 3 times a day for 1 month were also used. An oral carbonic anhydrase inhibitor was prescribed for the first 24 hours.

Laser in situ keratomileusis was performed at least 6 months after phakic IOL surgery. All sutures were removed at least 3 months before LASIK, and all eyes showed a stable refraction and corneal topographic pattern for at least 3 months before LASIK. The mean interval between phakic IOL surgery and LASIK was 6.8 months ± 0.8 (SD) (range 6 to 8 months). After phakic IOL implantation, 26 eyes had myopic astigmatism and 13 eyes had mixed astigmatism. In all patients, LASIK was performed with the Chiron Technolas Keracor 117 excimer laser with the PlanoScan program (Bausch & Lomb Surgical) and a 2.0 mm flying spot. Lamellar keratotomy was performed using the Hansatome microkeratome (Bausch & Lomb Surgical) to create a 9.0 mm flap. In the case of myopic astigmatism, the ablation was performed in the steep meridian (negative-cylinder ablation) and in the case of mixed astigmatism, the bitoric ablation technique was followed.20

After ablation, the flap was repositioned and the interface cleaned; perfect apposition was ensured by the preoperative corneal marks. The area was dried with surgical sponges and a jet of air. Postoperatively, all patients used TobraDex eyedrops 4 times daily for 1 week and artificial eyedrops (Acuolens) 3 to 4 times daily for 3 months.

Following the power vector method described by Thibos and Horner,21 the refractions obtained before surgery, immediately before the second procedure, and 12 months after LASIK were assessed. Any spherocylindrical refractive error was expressed by 3 dioptric powers—M, J0, J45—in which M was a spherical lens equal to the SE of the given refractive error and J0 and J45 were 2 Jackson crossed cylinders equivalent to the conventional cylinder. Manifest refractions in conventional script notation [S (sphere), C (cylinder) × φ (axis)] were converted to power vector coordinates and overall blurring strength (B) by the following formulas: Symbol.

Symbol
Symbol

The following scale was used to evaluate patient satisfaction at the last follow-up: 1 (poor), 2 (moderate), 3 (good), 4 (very good), and 5 (excellent). Glare, halos, pain, and foreign-body sensation were rated as 1 (very intense), 2 (intense), 3 (moderate), 4 (few), and 5 (none).

Statistical analysis was performed with the SPSS statistics software package SPSS/Pc +10.1 for Windows. Normality of the data in each group was confirmed by the normal probability plots. Visual acuity outcomes were transformed into logMAR notation for means computation and comparison. A series of paired t tests with the Bonferroni correction for multiple comparisons were performed. Monovariate t test and Hotelling T2 test of multivariate statistics were used for vector analysis.

Results

Thirty-nine eyes of 22 patients were included in the study. The mean age of the 12 men and 10 women was 26.3 ± 3.2 years (range 23 to 31 years). Preoperatively, the mean SE was +7.39 ± 1.30 D (range +5.25 to +9.75 D) and the mean ACD, 3.01 ± 0.16 mm (range 2.8 to 3.3 mm).

A summary of the results is shown in Table 1. Safety, efficacy, predictability, and stability of the combined procedure are shown in Figures 1 to 4.

Table 1
Table 1:
Summary of results.
Figure 1.
Figure 1.:
Safety: Cumulative decimal visual acuity bar chart comparing BCVA before and after bioptics (Artisan phakic IOL implantation followed by LASIK).
Figure 2.
Figure 2.:
Efficacy: Cumulative decimal visual acuity bar chart comparing BCVA before bioptics and UCVA after bioptics (Artisan phakic IOL implantation followed by LASIK).
Figure 3.
Figure 3.:
Predictability: Attempted versus achieved plot for SE (M) and for both astigmatic components (J0 and J45) of the power vector analysis before and after bioptics (Artisan phakic IOL implantation followed by LASIK).
Figure 4.
Figure 4.:
Stability: The mean SE before bioptics (PREOPSE), before LASIK (PRELSKSE), and 1 month (SE1), 3 months (SE3), and 12 months (SE12) after bioptics (Artisan phakic IOL implantation followed by LASIK).

Visual Acuity

Preoperatively, the mean UCVA was 0.57 ± 0.18 (logMar). After phakic IOL implantation, it was 0.46 ± 0.15 (logMar) and after LASIK, it increased to 0.18 ± 0.13 (logMAR). In 35 eyes (89.7%), the UCVA was 0.5 or better and in 16 eyes (41.0%), 0.8 or better. No eye had a UCVA worse than 0.4.

Preoperatively, the mean BCVA was 0.11 ± 0.11 (logMAR). After phakic IOL implantation, it was 0.13 ± 0.11 (logMAR) and 12 months after LASIK, it was 0.11 ± 0.10 (logMAR). There were statistically significant differences between BCVA before and after phakic IOL implantation (P=.008) but not between BCVA before surgery and at the end of the follow-up period (P=.91); ie, there was a significant decrease in BCVA after Artisan phakic IOL implantation but this effect was corrected after LASIK. One year after the bioptics procedure, 9 eyes (23.1%) lost 1 Snellen line of BCVA, 7 eyes (17.9%) gained 1 or more lines, and 1 eye (2.6%) gained 2 lines compared with the preoperative values.

Refraction

Preoperatively, the mean SE refraction was +7.39 ± 1.30 D (range +5.25 to +9.75 D). Postoperatively, it was −1.13 ± 0.80 D (range −2.50 to +0.75 D) before LASIK and +0.38 ± 0.57 D (−1.25 to +1.50 D), +0.18 ± 0.56 D (−1.50 to +0.75 D), and +0.06 ± 0.52 D (−1.50 to +0.75 D) 1, 3, and 12 months after LASIK, respectively. In 1 eye (2.6%), the change in SE was equal to or higher than 1.00 D over the follow-up period after LASIK. Twelve months after LASIK, 37 eyes (94.9%) were within ±1.00 D of emmetropia and 31 eyes (79.5%) were within ±0.50 D.

A statistical summary of the distribution of manifest refractive errors after vector conversion before and after phakic IOL surgery and 12 months after LASIK is shown in Table 2. A series of 3 monovariate t tests were performed to test the hypothesis that after bioptics, the mean of the 3 components of the power vector analysis was not statistically different than zero; ie, the refractive error was adequately corrected by the bioptics procedure. The results of the t tests revealed no difference from zero in the 3 cases (M, P=.45; J0, P=.41; J45, P=.23). The multivariate Hotelling T2 test confirmed that the mean power vector after surgery was not significantly different than a vector of zero length (P=.26); ie, bioptics achieved the objectives of fully correcting the refractive error.

Table 2
Table 2:
Distribution of manifest refractive errors after vector conversion.

Patient Satisfaction

Twelve months after bioptics, the mean satisfaction response was 4.46 ± 0.75. One patient who had surgery in 1 eye (2.6%) reported moderate global satisfaction (score of 2) because of significant halos at night. In 35 eyes (89.7%), the overall satisfaction of the patients was very good or excellent. The mean glare score was 4.10 ± 0.72. In 8 eyes (20.5%), glare was reported as moderate. In 1 eye (2.6%), the patient reported intense halos at night. Fourteen eyes (35.9%) were evaluated as having moderate halos at night; in 24 eyes (61.5%), the patients reported few or no halos. The overall score for halos was 3.87 ± 0.86. No patient reported significant pain or foreign-body sensation, with mean scores of 4.79 ± 0.41 and 4.41 ± 0.64, respectively.

Corneal Endothelium

A summary of corneal endothelial results is shown in Table 3. Preoperatively, the mean ECD was 3015 ± 252 cells/mm2 (range 2568 to 3546 cells/mm2); it decreased to 2779 ± 218 cells/mm2 (range 2356 to 3212 cells/mm2) after phakic IOL surgery (P<.001). Six to 8 months after phakic IOL implantation, the mean ECL was 7.8%. Twelve months after LASIK, the mean ECD was 2679 ± 157 cells/mm2 (range 2450 to 3000 cells/mm2), which was a 10.9% mean ECL 18 to 20 months after phakic IOL implantation (P<.001). After phakic IOL implantation but before LASIK, the mean ECD was 237 ± 111 cells/mm2 (range 26 to 508 cells/mm2). Twelve months after LASIK, it was 337 ± 155 cells/mm2 (range 68 to 656 cells/mm2). There were statistically significant differences between the mean ECD before and 12 months after LASIK (P<.001).

Table 3
Table 3:
Summary of corneal endothelium results.

The percentage of hexagonality was 67.7 ± 6.0 before phakic IOL surgery, 61.6 ± 4.9 immediately before LASIK (P<.001), and 62.1 ± 4.1 12 months after LASIK (P<.001). The mean baseline coefficient of variation in cell size was 0.294 ± 0.023 before phakic IOL implantation, 0.342 ± 0.027 before LASIK (P<.001), and 0.336 ± 0.030 12 months after LASIK (P<.001). There were no statistically significant differences between the percentages of hexagonality (P=.39) and the coefficients of variation (P=.19) before and 12 months after LASIK.

Complications and Reoperations

No sight-threatening complications occurred during the study. No eye needed explantation or repositioning of the phakic IOL. Various grades of iris atrophy were observed at the site of the Artisan phakic IOL implantation but were not clinically significant. Decentration of the phakic IOL optic of less than 1.0 mm was present in 3 eyes (7.7%), and these patients reported halos and glare under dim light but not during daylight. No eye developed IOP higher than 21 mm Hg in the postoperative period. After phakic IOL implantation, the postoperative inflammation was within normal limits in all but 1 eye (2.6%) in which precipitates on the surface of the phakic IOL were present at the end of the follow-up. There was no case of pupillary block or synechia formation.

The LASIK procedure was uneventful in all eyes with no complications related to the microkeratome lamellar cut. No clinical signs of intraocular inflammation were observed 24 hours after LASIK in eyes containing an Artisan phakic IOL for hyperopia (no flare or cells in the anterior chamber). No corneal edema, IOL displacement, pupillary block, pigment dispersion, or cataract or retinal complications were seen 1 year after bioptics.

Two eyes (5.1%) had a second LASIK procedure for significant residual ametropia. The corneal flap was relifted 12 months after the first LASIK procedure. Only the results of the first corneal surgery were considered in the analysis. In both eyes, the final UCVA was equal to the preoperative BCVA.

Discussion

This prospective study of 39 eyes evaluated a new approach for eyes with high hyperopia: combination of Artisan iris-fixated phakic IOL implantation and LASIK (bioptics). To our knowledge, there are no studies of the combined use of the Artisan phakic IOL and LASIK in eyes with high hyperopia. Yet corneal ECL is a well-known complication of iris-fixated phakic IOLs.11,22 Another objective of this study was to investigate whether LASIK performed in eyes containing an iris-fixated phakic IOL could produce damage to the corneal endothelium in addition to that caused by phakic IOL implantation.

In this 12-month follow-up study of the Artisan phakic IOL and LASIK, high levels of safety, efficacy, predictability, and stability were achieved. Twelve months after bioptics, nearly 95% of eyes were within ±1.00 D of the predicted correction and nearly 80% were within ±0.50 D. Astigmatism was reduced from a mean −2.00 ± 1.23 D to −0.49 ± 0.63 D at the end of follow-up. The refractive effect was stable, with only 2.6% of eyes changing refraction by 1.00 D or more between 3 months and 1 year of follow-up. The results of the present study indicate that the combination of the Artisan iris-claw phakic IOL and LASIK can be used successfully in eyes with high hyperopia.

Among the types of phakic IOLs currently available for the surgical correction of high hyperopia, the iris-fixated models seem to be better for eyes with a narrow angle since they are placed in the central anterior chamber.14 This is especially important in eyes with hyperopia greater than +6.00 D in which a shallow anterior chamber is a common finding, a factor that becomes more evident with increasing age.23 As the Artisan phakic IOL has no angular support, the possibility of peripheral contact with the corneal endothelium is decreased. Angle-supported phakic IOLs should be avoided in eyes with a shallow anterior chamber and a narrow angle because of the possibility of increased IOP and damage to the peripheral corneal endothelium.10 Unlike posterior chamber phakic IOLs, the Artisan IOL is situated far from the crystalline lens, thus decreasing the possibility of cataract complication.24 To our knowledge, there is only 1 case series study of the use of iris-fixated phakic IOLs in eyes with hyperopia. In this study, Alió and coauthors9 implanted the Artisan phakic IOL in a group of 29 eyes with primary hyperopia. At 1 year of follow-up, 79.3% of eyes were within ±0.50 D of the intended spherical correction and 96.6% were within ±1.00 D, but the astigmatic component of the refraction was not considered in the assessment of efficacy. When astigmatism was considered, only 50% of eyes were within ±0.50 D of emmetropia, suggesting that the Artisan phakic IOL procedure frequently must be enhanced by another refractive technique. In contrast to these data, 79.5% of the eyes in our study using the bioptics approach were within ±0.50 D of emmetropia.

Recently, toric phakic IOLs were introduced as a surgical option in eyes with high hyperopia with astigmatism. In a multicenter study, Dick et al.25 report the use of the Artisan toric phakic IOL for high myopia and high hyperopia. In the hyperopic group, 50% of the eyes that received the toric Artisan phakic IOL were within ±0.50 D of emmetropia and 100% were within ±1.00 D at 6 months. The results of the present study with 79.5% of eyes within ± 0.50 D of emmetropia are better than those of Dick et al.,25 although the eyes in our study had 2 surgical procedures. Implantation of the Artisan phakic IOL usually induces some astigmatism because the average incision for an IOL with an optic diameter of 5.0 mm ranges from 5.3 to 6.0 mm.25 Alió and coauthors9 report 1.48 ± 0.89 D of mean surgically induced astigmatism (SIA) after Artisan phakic IOL implantation, with as much as 4.31 D of astigmatism induced after surgery in 1 eye. The present study showed higher predictability with the bioptic approach than with the use of toric phakic IOLs. Research on a foldable iris-fixated phakic IOL that could be implanted through a small incision to decrease SIA is underway.

To calculate the power of the phakic IOL to be implanted, we considered only the spherical part of the refraction with the cylinder in negative sign, as astigmatism (preexisting plus or minus surgically induced) was corrected by LASIK in a second step. This is the reason that most eyes in the present study presented with myopic or mixed astigmatism after phakic IOL implantation. Myopic LASIK is superior to hyperopic LASIK in efficacy and predictability, and perfect centration is also more critical in hyperopic LASIK.26 Complications such as epithelial ingrowth and peripheral melting are more common after hyperopic LASIK because some of the ablation is performed beyond the flap margin. For these reasons, we preferred to perform LASIK for residual myopic or mixed astigmatism refractions. The lamellar cut in these eyes was performed cautiously because eyes with high hyperopia usually present steep corneas that may predispose to complications. Corneas with central keratometry steeper than 46.0 D are prone to buckling, and typically a flap with central thinning or buttonhole may develop. To decrease the incidence of these complications, the suction ring should be held firmly against the globe and adequate IOP increase should be confirmed before the keratome pass is made. Following these rules, we did not have complications during the lamellar cut.

An alternative surgical option to phakic IOL implantation in eyes with high hyperopia is CLE, but the loss of accommodation together with potential complications such as posterior capsule opacity, cystoid macular edema, and increased risk for retinal detachment make this option less than favorable in young patients. The use of phakic IOLs is still limited by serious potential complications such as uveitis, endophthalmitis, glaucoma, corneal endothelium damage, cataract, retinal detachment, and pupillary block.9–16 The present study showed that after Artisan phakic IOL implantation, 38.4% of eyes lost at least 1 line of BCVA and 5.1% lost 2 lines. This effect was partially corrected after LASIK; at the end of the bioptics procedure, 23.1% of eyes lost 1 line of BCVA but no eye lost 2 or more lines.

The loss of BCVA after Artisan phakic IOL implantation observed in more than one third of eyes in the present study could be explained by the decrease in the size of the retinal image that is produced in eyes with high hyperopia corrected by IOLs, contrary to the magnification obtained in myopic eyes. This effect was also found in hyperopic eyes by Alió and coauthors9 but only in 3.4% of the eyes that received the Artisan phakic IOL for hyperopia. Loss of BCVA after CLE for high hyperopia has been reported by Fink and coauthors,4 who found that nearly 30% of the eyes lost 1 line of BCVA. Whereas BCVA significantly decreased after Artisan phakic IOL surgery, it returned to the preoperative levels after LASIK enhancement. When LASIK is performed for the correction of astigmatism, it is common to observe an increase in BCVA after surgery.20 A cornea with high astigmatism causes greater distortion of the retinal image than a cornea with low astigmatism, and thus a reduction in the amount of astigmatism such as that obtained in our study could have improved visual acuity, reducing the retinal image distortion.

Alió and coauthors9 report postoperative acute uveitis with synechia formation in 15.8% of eyes in which the Artisan phakic IOL was used, a complication that was not found in the present study. We followed an aggressive regimen of topical steroids in the first 2 weeks after phakic IOL implantation. Potential causes of the postoperative inflammation include acute iritis due to excessive intraoperative manipulation and chronic iritis due to excessive tension of the iris from the claw mechanism. Too much posterior pressure on the pupillary margin should be avoided by not engaging too much tissue in the claw mechanism, and the claw should not be placed too close to the iris root to prevent interference with iris movement. Displacement, ovalization, and pupil deformation should be prevented by meticulously positioning the iris claw with an adequate amount of iris tissue to guarantee pupil movement. The central ACD was at least 2.8 mm to prevent complications such as corneal endothelial cell damage, cataract, and chronic uveitis. No chronic elevated postoperative IOP was found in the patient population, and in our experience, the risk for retinal detachment after phakic IOL implantation in eyes with high hyperopia is low.

The present study showed a mean ECL of 7.8% 6 to 8 months after phakic IOL surgery and 10.9% 12 months later (after LASIK). Alió and coauthors9 report cell loss of 6.8% at 6 months and 9.4% 1 year after implantation of the Artisan phakic IOL for hyperopia, percentages that are similar to the findings in the present study. In this study, the percentage of hexagonality and coefficient of variation showed statistically significant differences before and after phakic IOL surgery but not before and 12 months after LASIK, suggesting no additional damage caused by LASIK over that caused by Artisan phakic IOL implantation. Previous reports of the Artisan IOL in myopic eyes show larger ECLs and a trend toward chronic ECL.11,22 This may reflect differences in the surgical technique as our data do not appear to indicate the presence of high ECL as a trend, even though eyes with high hyperopia normally present a narrower anterior chamber than eyes with high myopia. Greater ECL has been reported with shallower anterior chambers and thicker phakic IOLs.11 Werblin27 compared ECL after phakic IOL implantation with that after phacoemulsification cataract surgery. He found that routine uneventful phacoemulsification produced a mean ECL of 8.8% 1 year postoperatively and 11.5% at 3 years, similar to the results obtained in the present study (7.8% at 7 months and 10.9% at 19 months). The main cause of ECL appears to be surgical trauma at the time of phakic IOL implantation, and the loss appears to stabilize over time. Longer follow-up is needed to ascertain the corneal endothelial effects of the Artisan phakic IOL in eyes with high hyperopia, and endothelial specular microscopy before surgery and at regular intervals in the follow-up period is mandatory when using this kind of phakic IOL.

There have been concerns about the safety of LASIK in eyes containing a phakic IOL.28,29 Güell et al.28 propose 2-step LASIK in which the corneal flap is created at the time of phakic IOL implantation and laser ablation is performed after the flap is lifted several months later to avoid possible contact between the phakic IOL and the corneal endothelium at the time of the keratome pass. However, to our knowledge, endothelial cell damage has not been reported after LASIK in eyes containing phakic IOLs. Güell et al.28 report no change in ECD before and after LASIK in a series of 8 eyes containing iris-fixated phakic IOLs for the correction of high myopia. Muñoz and coauthors29 report that the mean ECD before and after LASIK remained unchanged in 24 eyes containing an angle-supported phakic IOL for high myopia. However, specific LASIK complications such as epithelial ingrowth and peripheral flap melting are more common after LASIK retreatments than after primary LASIK.30 The theoretical protective effect of performing the corneal flap before phakic IOL implantation should be balanced against the possibility of a higher incidence of peripheral flap melting and epithelial ingrowth with the 2-step approach.

In the present study, patients were asked to rate their satisfaction and the mean score was approximately 4.5 (very good to excellent). In nearly 90% of eyes, the overall patient satisfaction was very good or excellent. One patient who had surgery in 1 eye (2.6%) reported moderate global satisfaction (score of 2) due to significant halos at night. It is noteworthy that in more than one third of the eyes evaluated (35.9%), the patient reported moderate halos at night. Glare and halos with iris-fixated phakic IOLs are related to decentration of the IOL, the presence of a large iridectomy, or a scotopic pupil larger than the IOL optic diameter. The eyes in this study had an intraoperative iridotomy using specially designed forceps and scissors,9 but a preoperative neodymium:YAG laser iridotomy is another option to avoid an excessively large intraoperative iridectomy. In our series, decentration of the phakic IOL optic of less than 1.0 mm was present in 3 eyes (7.7%). As pointed out by Pérez-Torregrosa et al.,31 the combination of slight decentration and large pupils could cause halos and glare under scotopic conditions. This appears to be the cause in our series. Menezo et al.32 found a glare rate of 3.2% with the iris-fixated phakic IOL in a myopic population, whereas Dick et al.25 found a rate of 5.7% using the toric model of the Artisan phakic IOL in myopic and hyperopic eyes. We found a 20.5% incidence of moderate glare, but no phakic IOL had to be explanted for this reason. The fundamentals of night glare after refractive surgery are not completely understood, as recently pointed out by Probst,33 and factors other than the relationship between pupil size and effective optical zone could play a role in the incidence of this significant problem.

Bioptics using the hyperopic Artisan phakic IOL followed by LASIK offers a safe and effective method for correcting high hyperopia with or without astigmatism. Bioptics reduced preoperative spherical and astigmatic errors with high predictability and stability. Good visual outcomes and high levels of patient satisfaction were achieved. Laser in situ keratomileusis did not add corneal endothelial cell damage to that produced by the Artisan phakic IOL surgery, suggesting that making the corneal flap in an eye containing an iris-fixated phakic IOL is a safe procedure. We recommend the bioptics approach in patients younger than 45 years of age with hyperopia higher than +5.00 D, especially in the presence of significant astigmatism. Bioptics may also be indicated for moderate hyperopia in eyes with steep corneas in which central corneal steepening induced by corneal surgery alone might be higher than 50.0 D. Preservation of accommodation, high efficacy, and predictability are factors that encourage the use of bioptics when considering the surgical options for patients with high hyperopia.

Further studies with larger numbers of patients and longer follow-up periods are needed to determine the long-term effects of Artisan phakic IOLs on the corneal endothelium, and potential risks must be evaluated before using any type of phakic IOL in eyes with high hyperopia. Loss of 1 line of BCVA should be expected in about one third of eyes implanted with the Artisan phakic IOL for high hyperopia. Halos and glare at night remain a potential problem in a significant percentage of patients who receive this type of IOL.

References

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