- Email: [email protected]
Phakic IOLs: A photo finish?
Phakic IOLs: A Photo Finish? ROGER F. STEINERT, MD
T
HE OPTICAL CORRECTION OF HIGH MYOPIA PRE-
sents formidable challenges to the ophthalmologist. Spectacle lenses must be thick, causing distortion of peripheral vision, prismatic effects, and spherical aberrations. Contact lenses reduce these problems, but the necessary peripheral thickness of the contact lens can cause discomfort and decentration of the contact lens. Not surprisingly, highly myopic patients are the most motivated group of patients seeking refractive surgery. Highly myopic patients have also been some of the most disappointed patients after corneal refractive surgery. Aggressive radial keratotomy, with very deep incisions and small optical zones, led to early complications of glare, irregular astigmatism, and corneal perforations and late complications of persistent diurnal fluctuation and a high rate of progressive myopia. With the introduction of excimer laser photoablation, surgeons turned to photorefractive keratectomy (PRK). With increasing depth of tissue removal came higher rates of optically disruptive corneal haze and scarring, regression of the initial correction, and substantially less predictability of the final correction compared to lower levels of myopia. Performing the laser ablation underneath a corneal flap created by a microkeratome (laser in-situ keratomileusis, or LASIK) first developed as an answer to these problems, removing most of the vexing problems of the wound healing response to the surface injury of PRK. Initial enthusiasm of refractive surgeons for LASIK as an answer to the challenge of high myopia gradually tempered when some patients with anatomically excellent results were unhappy with the quality of their vision. The most common complaints were glare and haloes, particularly at night. As understanding of sophisticated optics entered into clinical ophthalmology, surgeons came to appreciate that the problem was not the simple issue of pupil size, but instead the optics of the mid-peripheral cornea. Wavefront technology has demonstrated the deleterious impact of imposing a simple spherical correction on the cornea, with increased aberrations as the level of corneal flattening increased. While wavefront-guided aspheric ablation patterns may reduce these negative optical side effects, these patterns inherently consume more corneal tissue than
Accepted for publication September 20, 2004. From the University of California, Irvine, California. Inquiries to Roger F. Steinert, MD, University of California, Irvine, 118 Med Surge I, Irvine, CA 92697-4375; fax: 949-824-7645; email: [email protected] 0002-9394/04/$30.00 doi:10.1016/j.ajopht.2004.09.054
©
2004 BY
simple spherical corrections. Both the high myopic correction itself and attempts to improve the mid-peripheral optics collide with the limit of leaving enough corneal stroma to maintain structural integrity and avoid postoperative corneal ectasia. The alternative surgical site for optical correction is, therefore, intraocular. Refractive lens exchange, or clear lens extraction, uses the highly developed technology of phacoemulsification and intraocular lens implantation. Accuracy of the IOL power selection, while not perfect, is better than the predictability of corneal refractive surgery for high myopia. On the downside, however, is the loss of accommodation unless an accommodating IOL is implanted successfully. At best, the surgery carries the risks of cataract surgery. While the frequency of most complications is low, the loss of vision can be severe and permanent.1 In the setting of high myopia, however, the increased risk of retinal detachment is particularly threatening.2 In high myopia, the detachment may be more difficult to repair and more likely to leave permanent loss of vision. Retinal surgeons generally believe that neither preoperative and postoperative exams, nor “prophylactic” peripheral retinal photocoagulation, can reduce the risk of retinal detachment in high myopia to the rate of emmetropia. These optical, anatomical, and surgical realities are the stimulus, therefore, for the development of a safe and effective intraocular lens that can be implanted in phakic patients. By retaining the natural crystalline lens, accommodation is not affected, and the risk of retinal detachment should be lower than with refractive lens exchange, although not necessarily as low as unoperated highly myopic eyes.3 Other risks of intraocular surgery remain, particularly endophthalmitis. Of particular concern with phakic IOLs is the long term tolerance of the lens. Phakic IOLs must be fixated in an eye with less space compared to pseudophakic IOLs, attributable to the presence of the crystalline lens.4 The crystalline lens itself is particularly sensitive to injury, whether traumatic or inflammatory.5 Corneal endothelial cells are in close proximity, and the iris is both fragile and highly reactive.6 Patients who are candidates for a phakic IOL are considerably younger on the average than cataract surgical patients; phakic IOLs are going to need to be in place for many decades without adverse effects on any of these structures.7
ELSEVIER INC. ALL
RIGHTS RESERVED.
849
In sum, the bar is high. While current capsular bag fixated IOLs have an excellent track record with cataract surgery, even these lenses are not perfect. Sporadic problems arise. None of the current pseudophakic IOLs is proven to be problem free in eyes expected to have a life span that may exceed a half century. Additionally, current pseudophakic posterior chamber IOLs were the end result of many other designs that failed, leaving many damaged eyes along the path of progress. We must avoid repeating these mistakes and, we can hope, avoid making new mistakes in attempting to correct an optical anomaly in these relatively fragile highly myopic eyes. In this month’s JOURNAL, Baumeister, Buhren, and Kohnen report their assessment of the anatomical stability of phakic IOLs, as determined by Scheimplug photography. They compared three models of IOLs, one model representative of each of the three potential locations for a pseudophakic IOL: anterior chamber angle fixated, anterior chamber mid-peripheral iris fixated, and posterior chamber, between iris and crystalline lens. The results for two of the three models are worrisome. In cataract surgery, two clinical truisms have developed for angle fixated anterior chamber IOLs (AC IOLs). The first is that AC IOLs are easy to insert, but difficult to insert properly. The second truism is that an AC IOL can be too long or too short, but almost never is perfect. Manufacturers of pseudophakic AC IOLs have learned over the years to make haptics that are flexible, with minimal angle and iris contact, and stable in position. Yet these lenses are still sometimes malpositioned or the source of chronic inflammation. The challenge for phakic myopes is greater, with less anterior chamber depth and less angle space than pseudophakic eyes. In phakic AC IOLs, endothelial cell loss and progressive pupil ovalization because of iris tissue reaction to the AC IOL have been two of the special problems that have driven the evolution in the design of these IOLs.8,9 In the current study, four of 10 AC IOLs rotated months after implantation. Perhaps the fault is not the lens design but instead the surgeon’s choice of IOL length, but the imprecision of using measurement of corneal diameter as a substitute for direct measurement of angle diameter,10 coupled with the surgeon’s desire to avoid pupil ovalling because of an overly large AC IOL, will tend to cause persistence of sporadic errors of undersizing the AC IOL. Rotation of phakic AC IOLs was not unique to this study.11 In the 16 eyes with the sulcus fixated posterior chamber plate IOL (PC IOL), no rotation occurred. However, the distance between the anterior lens capsule and the PC IOL progressively declined over the 12 months of follow-up. The authors’ methodology does not distinguish between a thickening of the crystalline lens vs a posterior movement—a reduction in vaulting— of the PC IOL. Neither explanation is without concern. Accelerated thickening of the crystalline lens suggests that the lens is undergoing changes that will later lead to lens opacity and the need for 850
AMERICAN JOURNAL
cataract surgery. Reduction in vaulting means that either the PC IOL itself is structurally unstable or that the haptics are progressively eroding into the supporting tissue. The precise location of fixation of these lenses cannot be determined in each case.12 The ciliary sulcus is a variable structure, sometimes small or absent. The PC IOL may, therefore, rest in the sulcus, or on the ciliary processes, or even be supported by zonular fibers.13 Erosion into the ciliary sulcus might be acceptable as long as it is limited in extent and bleeding from the anterior ciliary artery does not occur. Erosion into or progressive posterior movement along the ciliary processes is less likely to be acceptable, as is equally true for pressure on zonular fibers. Anecdotal reports of phakic PC IOLs slipping into the vitreous cavity have recently occurred (Film Festival, Annual Meeting of the American Society of Cataract and Refractive Surgery, San Diego, May 2004). In addition to these concerns, advocates of these phakic PC IOLs have postulated that an aqueous filled space between the posterior surface of the IOL and the anterior crystalline lens capsule is the reason that cataracts will not develop. The Scheimplug photos included in this report show complete disappearance of the space in at least one case; the contact of the phakic PC IOL with the lens has been observed in other studies as well, along with cataract formation and endothelial cell loss.14 Whether cataract formation in relation to phakic PC IOLs is largely attributable to traumatic insertion,15 or whether contact of the PC IOL and the crystalline lens will be problematic remains to be determined. Does this study definitively prove that these two lens designs are unacceptable? The answer is not unequivocally “Yes,” but this study clearly documents the basis for concerns that must be addressed by other studies before these IOLs can be considered non-investigational. Other angle fixated AC IOLs and phakic PC IOL designs may satisfactorily solve these problems if acceptable results are demonstrated by further studies. And, while the iris-fixated IOL showed no problems in this study, other concerns such as the potential for inflammation,16 progressive endothelial cell loss, cataract formation, and the challenge of surgical implantation are issues to be addressed by studies with other methodologies.17,18 Despite pressures on refractive surgeons from eager patients to implant pseudophakic IOLs to solve the optical problems of high myopia, the study by Baumeister and coworkers reported this month shines a bright yellow caution light. Patients are entitled to the wisdom of the surgeon, over and beyond regulatory approval. The surgeon does not have an infallible “crystal ball” to foresee the future, unfortunately. The surgeon must assess and balance often contradictory information. The first obligation is, as much as humanly possible, to do no harm. At this time, proceeding slowly with the adoption of any of the phakic IOLs seems the most prudent course. OF
OPHTHALMOLOGY
NOVEMBER 2004
REFERENCES 1. Steinert RF. High myopia. In: Steinert RF, editor. Cataract surgery: technique, complications, and management. 2nd ed. Philadelphia: WB Saunders, 2004:353–355. 2. Ripandelli G, Scassa Parisi V, et al. Cataract surgery as a risk factor for retinal detachment in very myopic eyes. Ophthalmology 2003;110:2355–2361. 3. Foss AJ, Rosen PH, Cooling RJ. Retinal detachment following anterior chamber lens implantation for the correction of ultra-high myopia in phakic eyes. Br J Ophthalmol 1993;77: 212–213. 4. Trindade F, Pereira F. Cataract formation after posterior chamber phakic intraocular lens implantation. J Cataract Refract Surg 1998;24:1661–1663. 5. Menezo JL, Peris-Martinez C, Cisneros AL, Martinez-Costa R. Phakic intraocular lenses to correct high myopia: Adatomed, staar, and artisan. J Cataract Refract Surg 2004;30:33– 44. 6. Allemann N, Chamon W, Tanaka HM, et al. Myopic angle-supported intraocular lenses: two year follow-up. Ophthalmology 2000;107:1549 –1554. 7. Perez-Santonja JJ, Iradier MT, Benitez del Castillo JM, et al. Chronic subclinical inflammation in phakic eyes with intraocular lenses. J Cataract Refract Surg 1996;22:183–187. 8. Baikoff G, Arne JL, Bokobza Y, et al. Angle-fixated anterior chamber phakic intraocular lens for myopia of ⫺7 to ⫺19 diopters. J Refract Surg 1998;14:282–293. 9. Allemann N, Chamon W, Tanaka HM. Myopic anglesupported intraocular lenses: Two-year follow-up. Ophthalmology 2000;107:1549 –1554. 10. Pop M, Payette Y, Mansour M. Predicting sulcus size using
VOL. 138, NO. 5
11.
12.
13.
14.
15.
16.
17.
18.
EDITORIAL
ocular measurements. J Cataract Refract Surg 2001;27:1033– 1038. Perez-Santonja JJ, Alio JL, Jimenez-Alfaro I, Zato MA. Surgical correction of severe myopia with an angle-supported phakic intraocular lens. J Cataract Refract Surg 2000;26: 1288 –1302. Garcia-Feijoo J, Alfaro IJ, Cuina-Sardina R et al. Ultrasound biomicroscopy examination of posterior chamber phakic IOL position. Ophthalmology 2003;110:163–172. Hansen SO, Tetz MR, Solomon KD, et al. Decentration of flexible loop posterior chamber intraocular lenses in a series of 222 postmortem eyes. Ophthalmology 1988;95:344 –399. Jimenez-Alfaro I, Benitez del Castillo JM, Garcia-Feijoo J, et al. Safety of posterior chamber phakic intraocular lenses for the correction of high myopia: anterior segment changes after posterior chamber phakic intraocular lens implantation. Ophthalmology 2001;108:90 –99. Sanchez-Galeana CA, Smith RJ, Sanders DR, et al. Lens opacities after posterior chamber phakic intraocular lens implantation. Ophthalmology 2003;110:781–785. Perez-Santonja JJ, Iradier MT, Benitez del Castillo, et al. Chronic subclinical inflammation in phakic eyes with intraocular lenses to correct myopia. J Cataract Refract Surg. 1997;23:815– 817. Pop M, Payette Y. Initial results of endothelial cell counts after Artisan lens for phakic eyes: An evaluation of the United States Food and Drug Administration Ophtec Study. Ophthalmology 2004;111:309 –317. Menezo JL, Peris-Martinez C, Cisneros AL, Martinez-Costa R. Phakic intraocular lenses to correct high myopia: Adatomed, Staar, and Artisan. J Cataract Refract Surg 2004;30:33– 44.
851
T
HE OPTICAL CORRECTION OF HIGH MYOPIA PRE-
sents formidable challenges to the ophthalmologist. Spectacle lenses must be thick, causing distortion of peripheral vision, prismatic effects, and spherical aberrations. Contact lenses reduce these problems, but the necessary peripheral thickness of the contact lens can cause discomfort and decentration of the contact lens. Not surprisingly, highly myopic patients are the most motivated group of patients seeking refractive surgery. Highly myopic patients have also been some of the most disappointed patients after corneal refractive surgery. Aggressive radial keratotomy, with very deep incisions and small optical zones, led to early complications of glare, irregular astigmatism, and corneal perforations and late complications of persistent diurnal fluctuation and a high rate of progressive myopia. With the introduction of excimer laser photoablation, surgeons turned to photorefractive keratectomy (PRK). With increasing depth of tissue removal came higher rates of optically disruptive corneal haze and scarring, regression of the initial correction, and substantially less predictability of the final correction compared to lower levels of myopia. Performing the laser ablation underneath a corneal flap created by a microkeratome (laser in-situ keratomileusis, or LASIK) first developed as an answer to these problems, removing most of the vexing problems of the wound healing response to the surface injury of PRK. Initial enthusiasm of refractive surgeons for LASIK as an answer to the challenge of high myopia gradually tempered when some patients with anatomically excellent results were unhappy with the quality of their vision. The most common complaints were glare and haloes, particularly at night. As understanding of sophisticated optics entered into clinical ophthalmology, surgeons came to appreciate that the problem was not the simple issue of pupil size, but instead the optics of the mid-peripheral cornea. Wavefront technology has demonstrated the deleterious impact of imposing a simple spherical correction on the cornea, with increased aberrations as the level of corneal flattening increased. While wavefront-guided aspheric ablation patterns may reduce these negative optical side effects, these patterns inherently consume more corneal tissue than
Accepted for publication September 20, 2004. From the University of California, Irvine, California. Inquiries to Roger F. Steinert, MD, University of California, Irvine, 118 Med Surge I, Irvine, CA 92697-4375; fax: 949-824-7645; email: [email protected] 0002-9394/04/$30.00 doi:10.1016/j.ajopht.2004.09.054
©
2004 BY
simple spherical corrections. Both the high myopic correction itself and attempts to improve the mid-peripheral optics collide with the limit of leaving enough corneal stroma to maintain structural integrity and avoid postoperative corneal ectasia. The alternative surgical site for optical correction is, therefore, intraocular. Refractive lens exchange, or clear lens extraction, uses the highly developed technology of phacoemulsification and intraocular lens implantation. Accuracy of the IOL power selection, while not perfect, is better than the predictability of corneal refractive surgery for high myopia. On the downside, however, is the loss of accommodation unless an accommodating IOL is implanted successfully. At best, the surgery carries the risks of cataract surgery. While the frequency of most complications is low, the loss of vision can be severe and permanent.1 In the setting of high myopia, however, the increased risk of retinal detachment is particularly threatening.2 In high myopia, the detachment may be more difficult to repair and more likely to leave permanent loss of vision. Retinal surgeons generally believe that neither preoperative and postoperative exams, nor “prophylactic” peripheral retinal photocoagulation, can reduce the risk of retinal detachment in high myopia to the rate of emmetropia. These optical, anatomical, and surgical realities are the stimulus, therefore, for the development of a safe and effective intraocular lens that can be implanted in phakic patients. By retaining the natural crystalline lens, accommodation is not affected, and the risk of retinal detachment should be lower than with refractive lens exchange, although not necessarily as low as unoperated highly myopic eyes.3 Other risks of intraocular surgery remain, particularly endophthalmitis. Of particular concern with phakic IOLs is the long term tolerance of the lens. Phakic IOLs must be fixated in an eye with less space compared to pseudophakic IOLs, attributable to the presence of the crystalline lens.4 The crystalline lens itself is particularly sensitive to injury, whether traumatic or inflammatory.5 Corneal endothelial cells are in close proximity, and the iris is both fragile and highly reactive.6 Patients who are candidates for a phakic IOL are considerably younger on the average than cataract surgical patients; phakic IOLs are going to need to be in place for many decades without adverse effects on any of these structures.7
ELSEVIER INC. ALL
RIGHTS RESERVED.
849
In sum, the bar is high. While current capsular bag fixated IOLs have an excellent track record with cataract surgery, even these lenses are not perfect. Sporadic problems arise. None of the current pseudophakic IOLs is proven to be problem free in eyes expected to have a life span that may exceed a half century. Additionally, current pseudophakic posterior chamber IOLs were the end result of many other designs that failed, leaving many damaged eyes along the path of progress. We must avoid repeating these mistakes and, we can hope, avoid making new mistakes in attempting to correct an optical anomaly in these relatively fragile highly myopic eyes. In this month’s JOURNAL, Baumeister, Buhren, and Kohnen report their assessment of the anatomical stability of phakic IOLs, as determined by Scheimplug photography. They compared three models of IOLs, one model representative of each of the three potential locations for a pseudophakic IOL: anterior chamber angle fixated, anterior chamber mid-peripheral iris fixated, and posterior chamber, between iris and crystalline lens. The results for two of the three models are worrisome. In cataract surgery, two clinical truisms have developed for angle fixated anterior chamber IOLs (AC IOLs). The first is that AC IOLs are easy to insert, but difficult to insert properly. The second truism is that an AC IOL can be too long or too short, but almost never is perfect. Manufacturers of pseudophakic AC IOLs have learned over the years to make haptics that are flexible, with minimal angle and iris contact, and stable in position. Yet these lenses are still sometimes malpositioned or the source of chronic inflammation. The challenge for phakic myopes is greater, with less anterior chamber depth and less angle space than pseudophakic eyes. In phakic AC IOLs, endothelial cell loss and progressive pupil ovalization because of iris tissue reaction to the AC IOL have been two of the special problems that have driven the evolution in the design of these IOLs.8,9 In the current study, four of 10 AC IOLs rotated months after implantation. Perhaps the fault is not the lens design but instead the surgeon’s choice of IOL length, but the imprecision of using measurement of corneal diameter as a substitute for direct measurement of angle diameter,10 coupled with the surgeon’s desire to avoid pupil ovalling because of an overly large AC IOL, will tend to cause persistence of sporadic errors of undersizing the AC IOL. Rotation of phakic AC IOLs was not unique to this study.11 In the 16 eyes with the sulcus fixated posterior chamber plate IOL (PC IOL), no rotation occurred. However, the distance between the anterior lens capsule and the PC IOL progressively declined over the 12 months of follow-up. The authors’ methodology does not distinguish between a thickening of the crystalline lens vs a posterior movement—a reduction in vaulting— of the PC IOL. Neither explanation is without concern. Accelerated thickening of the crystalline lens suggests that the lens is undergoing changes that will later lead to lens opacity and the need for 850
AMERICAN JOURNAL
cataract surgery. Reduction in vaulting means that either the PC IOL itself is structurally unstable or that the haptics are progressively eroding into the supporting tissue. The precise location of fixation of these lenses cannot be determined in each case.12 The ciliary sulcus is a variable structure, sometimes small or absent. The PC IOL may, therefore, rest in the sulcus, or on the ciliary processes, or even be supported by zonular fibers.13 Erosion into the ciliary sulcus might be acceptable as long as it is limited in extent and bleeding from the anterior ciliary artery does not occur. Erosion into or progressive posterior movement along the ciliary processes is less likely to be acceptable, as is equally true for pressure on zonular fibers. Anecdotal reports of phakic PC IOLs slipping into the vitreous cavity have recently occurred (Film Festival, Annual Meeting of the American Society of Cataract and Refractive Surgery, San Diego, May 2004). In addition to these concerns, advocates of these phakic PC IOLs have postulated that an aqueous filled space between the posterior surface of the IOL and the anterior crystalline lens capsule is the reason that cataracts will not develop. The Scheimplug photos included in this report show complete disappearance of the space in at least one case; the contact of the phakic PC IOL with the lens has been observed in other studies as well, along with cataract formation and endothelial cell loss.14 Whether cataract formation in relation to phakic PC IOLs is largely attributable to traumatic insertion,15 or whether contact of the PC IOL and the crystalline lens will be problematic remains to be determined. Does this study definitively prove that these two lens designs are unacceptable? The answer is not unequivocally “Yes,” but this study clearly documents the basis for concerns that must be addressed by other studies before these IOLs can be considered non-investigational. Other angle fixated AC IOLs and phakic PC IOL designs may satisfactorily solve these problems if acceptable results are demonstrated by further studies. And, while the iris-fixated IOL showed no problems in this study, other concerns such as the potential for inflammation,16 progressive endothelial cell loss, cataract formation, and the challenge of surgical implantation are issues to be addressed by studies with other methodologies.17,18 Despite pressures on refractive surgeons from eager patients to implant pseudophakic IOLs to solve the optical problems of high myopia, the study by Baumeister and coworkers reported this month shines a bright yellow caution light. Patients are entitled to the wisdom of the surgeon, over and beyond regulatory approval. The surgeon does not have an infallible “crystal ball” to foresee the future, unfortunately. The surgeon must assess and balance often contradictory information. The first obligation is, as much as humanly possible, to do no harm. At this time, proceeding slowly with the adoption of any of the phakic IOLs seems the most prudent course. OF
OPHTHALMOLOGY
NOVEMBER 2004
REFERENCES 1. Steinert RF. High myopia. In: Steinert RF, editor. Cataract surgery: technique, complications, and management. 2nd ed. Philadelphia: WB Saunders, 2004:353–355. 2. Ripandelli G, Scassa Parisi V, et al. Cataract surgery as a risk factor for retinal detachment in very myopic eyes. Ophthalmology 2003;110:2355–2361. 3. Foss AJ, Rosen PH, Cooling RJ. Retinal detachment following anterior chamber lens implantation for the correction of ultra-high myopia in phakic eyes. Br J Ophthalmol 1993;77: 212–213. 4. Trindade F, Pereira F. Cataract formation after posterior chamber phakic intraocular lens implantation. J Cataract Refract Surg 1998;24:1661–1663. 5. Menezo JL, Peris-Martinez C, Cisneros AL, Martinez-Costa R. Phakic intraocular lenses to correct high myopia: Adatomed, staar, and artisan. J Cataract Refract Surg 2004;30:33– 44. 6. Allemann N, Chamon W, Tanaka HM, et al. Myopic angle-supported intraocular lenses: two year follow-up. Ophthalmology 2000;107:1549 –1554. 7. Perez-Santonja JJ, Iradier MT, Benitez del Castillo JM, et al. Chronic subclinical inflammation in phakic eyes with intraocular lenses. J Cataract Refract Surg 1996;22:183–187. 8. Baikoff G, Arne JL, Bokobza Y, et al. Angle-fixated anterior chamber phakic intraocular lens for myopia of ⫺7 to ⫺19 diopters. J Refract Surg 1998;14:282–293. 9. Allemann N, Chamon W, Tanaka HM. Myopic anglesupported intraocular lenses: Two-year follow-up. Ophthalmology 2000;107:1549 –1554. 10. Pop M, Payette Y, Mansour M. Predicting sulcus size using
VOL. 138, NO. 5
11.
12.
13.
14.
15.
16.
17.
18.
EDITORIAL
ocular measurements. J Cataract Refract Surg 2001;27:1033– 1038. Perez-Santonja JJ, Alio JL, Jimenez-Alfaro I, Zato MA. Surgical correction of severe myopia with an angle-supported phakic intraocular lens. J Cataract Refract Surg 2000;26: 1288 –1302. Garcia-Feijoo J, Alfaro IJ, Cuina-Sardina R et al. Ultrasound biomicroscopy examination of posterior chamber phakic IOL position. Ophthalmology 2003;110:163–172. Hansen SO, Tetz MR, Solomon KD, et al. Decentration of flexible loop posterior chamber intraocular lenses in a series of 222 postmortem eyes. Ophthalmology 1988;95:344 –399. Jimenez-Alfaro I, Benitez del Castillo JM, Garcia-Feijoo J, et al. Safety of posterior chamber phakic intraocular lenses for the correction of high myopia: anterior segment changes after posterior chamber phakic intraocular lens implantation. Ophthalmology 2001;108:90 –99. Sanchez-Galeana CA, Smith RJ, Sanders DR, et al. Lens opacities after posterior chamber phakic intraocular lens implantation. Ophthalmology 2003;110:781–785. Perez-Santonja JJ, Iradier MT, Benitez del Castillo, et al. Chronic subclinical inflammation in phakic eyes with intraocular lenses to correct myopia. J Cataract Refract Surg. 1997;23:815– 817. Pop M, Payette Y. Initial results of endothelial cell counts after Artisan lens for phakic eyes: An evaluation of the United States Food and Drug Administration Ophtec Study. Ophthalmology 2004;111:309 –317. Menezo JL, Peris-Martinez C, Cisneros AL, Martinez-Costa R. Phakic intraocular lenses to correct high myopia: Adatomed, Staar, and Artisan. J Cataract Refract Surg 2004;30:33– 44.
851