- Email: [email protected]
Spontaneous, bilateral intraocular lens dislocation in a patient with exfoliation syndrome
Optometry (2007) 78, 220-224
Spontaneous, bilateral intraocular lens dislocation in a patient with exfoliation syndrome Daniella Rutner, O.D., M.S., and Richard J. Madonna, O.D., M.A. Department of Clinical Science, SUNY State College of Optometry, New York, New York. KEYWORDS Glaucoma; Psuedoexfoliation; Exfoliation; Lens subluxation; Cataract; Pseudophakia; Phacodonesis; Phacoemulsification surgery
Abstract BACKGROUND: Exfoliation syndrome (XFS) is a relatively common age-related disorder characterized by the production and progressive accumulation of a fibrillar extracellular material in numerous ocular tissues and throughout the body. XFS is a known identifiable cause of open-angle glaucoma. However, because of its widespread distribution, other structures in the eye are affected. Because of weakening of the zonular apparatus and posterior capsule, and subsequent loss of support for the lens or posterior chamber intraocular lenses (IOLs), its presence must be factored into the pre- and postoperative management of persons undergoing cataract surgery. CASE REPORT: An 89-year-old white female presented with the sudden onset of decreased vision in her left eye. She had a history of uncomplicated cataract extraction and posterior chamber IOL implantation in each eye about 10 years previously. She was also known to have XFS. Examination found XFS, a dislocated posterior chamber IOL, anterior uveitis, and markedly elevated intraocular pressure. After stabilizing the eye medically, the patient presented 5 months later with the same condition in the right eye. This eye was also stabilized medically. The patient refused further treatment. CONCLUSIONS: It is imperative that the comanaging optometrist and cataract surgeon be cognizant of the presence of XFS when planning cataract surgery. However, the effects of XFS may not be seen for many years after apparently successful cataract surgery. Optometry 2007;78:220-224
Exfoliation syndrome (pseudoexfoliation syndrome, XFS, PEX, PES, or PXE) is a relatively common age-related ocular disorder that is well known to be a cause of openangle glaucoma. XFS is characterized by the production and progressive accumulation of a fibrillar extracellular material in many ocular tissues and throughout the body. It affects 4% to 6% of patients older than 60 years and as many as 8% to 35% over the age of 70.1 A higher incidence is found in certain ethnic groups as diverse as northern Scandinavians, Saudi Arabians, and Navajo Indians.1 XFS is best known as the most common identifiable cause of open-angle glau-
Corresponding author: Daniella Rutner, O.D., M.S., SUNY State College of Optometry, 33 West 42nd Street, New York, New York 10036. E-mail: [email protected]
coma, but it affects all structures in the eye.2 Additionally, XFS material has been found in skin, heart, lungs, brains, kidney, liver, and gallbladder. The significance of these deposits has not been clearly elucidated (see Table 1).3 The classic diagnostic sign of XFS is a characteristic unilateral or bilateral bull’s-eye appearance of the anterior lens surface, produced by pupillary wiping of a ring of exfoliative material from the lens surface. Occasionally, white flakes on the pupillary border of the iris may be the only subtle sign present.1 Early clinical diagnosis is made by careful slit lamp examination looking for exfoliative material on the anterior lens capsule, pupillary frill, and the zonules. In cases in which exfoliative material is not readily visible, the earliest change may be iris transillumination defects caused by loss of melanin. These transillu-
1529-1839/07/$ -see front matter © 2007 American Optometric Association. All rights reserved. doi:10.1016/j.optm.2006.12.012
Rutner and Madonna Table 1
Clinical Care
221
Ocular and systemic disease associated with XFS
Ocular disease Glaucoma Lens dislocation Blood-aqueous breakdown Pigment dispersion Iris complications Corneal endothelial decompensation Increased incidence of central retinal vein occlusion Systemic disease Densorianeural hearing loss Transient ischemic attacks Stroke Heart disease Aneurysms of the abdominal aorta
mination defects may be found in the sphincter region or throughout the iris. Increased pigment deposition on anterior segment structures such as trabecular meshwork or the existence of circular or segmental posterior synechiae, as well as poor dilation or anterior chamber melanin dispersion after dilation should also increase suspicion of XFS.4 Intraoperative lens dislocation in patients with XFS is a well-recognized condition.3,4 Less is known about the longterm consequences of XFS on the stability of posterior chamber intraocular lenses (IOLs).
Case report An 89-year-old white woman was referred for evaluation of marked decrease in visual acuity in her left eye and an increase in intraocular pressure (IOP). She was known to have moderately reduced visual acuity because of geo-
Figure 1
Retroillumination shows dislocated IOL within capsular bag.
Figure 2
Direct illumination shows dislocated IOL within capsular bag.
graphic atrophy associated with age-related macular degeneration. She had XFS diagnosed in 1988 (before cataract surgery) but had shown no elevation of IOP or sign of glaucoma since that time. She had undergone uncomplicated extracapsular cataract extraction with posterior chamber IOL implantation in both eyes about 10 years before the current visit. Presenting corrected visual acuities were 20/40 in the right eye (O.D.) and counting fingers in the left eye (O.S.). The pupils responded to light sluggishly but equally, and there was no relative afferent pupillary defect. Slit lamp evaluation showed exfoliative material at the pupillary frill in both eyes. There was microcystic edema O.S. A dislocated posterior chamber IOL within the capsular bag was noted O.S. The IOL had fallen inferiorly, but the top portion of the IOL was visible in the inferior portion of the pupil (see Figures 1 through 3). The patient denied any history of trauma or fall. Anterior chamber showed grade 1 cells and flare. IOPs were 17 mmHg in the right eye and 41 mmHg in the left eye. On 4-mirror gonioscopy, the angle was open to ciliary body in both eyes with grade 3 pigment evenly dispersed. Ultrasound B scan was performed in the office, and the retina was found to be flat and intact. In the office, she was treated with 0.5% timolol maleate/0.2% dorzolamide (Cosopt; Merck & Co. Inc., West Point, Pennsylvania) eye drops and oral acetazolamide in an effort to rapidly reduce the IOP in the left eye. With the IOP reduced to 25 mmHg, she was dismissed on topical 0.005% latanoprost (Xalatan; Pfizer Pharmaceuticals, New York, New York) at bedtime O.S. and Cosopt twice daily O.S. and told to return in 1 day.
222
Optometry, Vol 78, No 5, May 2007 and 14 mmHg O.S. The patient was prescribed Cosopt twice daily in both eyes (OU) and Xalatan at bedtime OU. One week later, the visual acuities were a 400 letter at 4 inches O.D. and a 400 letter at 8 inches O.S. Slit lamp examination was unchanged, and IOPs were 17 mmHg O.D. and 17 mmHg O.S. Refraction improved vision to 20/400 O.D. with a ⫹9.00 diopter (D) sphere, whereas an objective refraction of ⫹12.00 D sphere did not improve vision OS. The patient decided she was not interested in surgery because she felt she could accomplish her activities of daily living with the prescribed spectacle correction.
Discussion
Figure 3
Undilated view shows exfoliative material on pupillary margin with free-floating zonules visible through the pupil.
The patient could not return the next day, but instead was seen 3 days later. Visual acuities remained 20/40 O.D. and counting fingers O.S. IOPs were now reduced to 15 mmHg O.D. and 10 mmHg O.S. She was told to continue her current eye drop regimen and asked to return in 1 week. The patient actually returned in 2 weeks with no change in visual acuity, and IOPs were well controlled at 14 mmHg O.D. and 15 mmHg O.S. Xalatan use was discontinued, and the patient was told to continue taking Cosopt twice daily O.S. and return 2 weeks later. At the 2-week visit, visual acuities remained unchanged, and IOPs were 14 mmHg O.D. and 26 mmHg O.S. At this time, the patient was counseled regarding surgery to reposition the IOL. She preferred no surgical intervention. She was instructed to restart taking Xalatan at bedtime O.S. and continue Cosopt twice a day O.S. and was asked to return in 2 weeks. At that visit, visual acuities remained stable, and IOPs were 16 mmHg O.D. and 14 mmHg O.S. Over the course of the next 2 months, there was no change in her clinical condition, and the patient reiterated that she was not interested in surgery. The patient returned urgently 1 month later (about 4 months after the initial visit) complaining of a marked decrease in vision in her right eye. Visual acuities were hand motion O.D. and counting fingers O.S. Slit lamp evaluation now found dislocated IOLs in both eyes. The appearance of the right eye was very similar to the appearance of the left eye at the initial presentation. IOPs were 32 mmHg O.D.
Exfoliation syndrome is a relatively common ocular disorder. The exact cause of this condition remains unknown. Speculation is that there is an overproduction of extracellular matrix material by lens, iris, and ciliary epithelial cells alone or in combination with poor resorption of this material. The exfoliative material then accumulates on the surfaces of structures that come in contact with aqueous, including zonular fibers, iris, ciliary body, trabecular meshwork, and the corneal endothelium. Because of its widespread distribution in the eye, it can cause weakening of the zonular apparatus and posterior capsule and subsequent loss of support for the crystalline lens or posterior chamber IOL. Zonular dysfunction, marked by increased friability and decreased tensile strength, may lead to lens or IOL dislocation.3,4 Exfoliative material has been shown to disrupt the zonules at 3 levels: (1) at the origin of the ciliary body where they are anchored, (2) in the pars plicata of the ciliary body where they pass alongside the ciliary processes, and (3) at their attachment to the anterior lens capsule.4 When cataract surgery and IOL implantation is planned in patients with XFS, the status of the zonules must be evaluated carefully. The presence of phacodonesis or iridodonesis indicates reduced zonular integrity and the potential for poor zonular support of the IOL. Thus, caution needs to be exercised during routine dilation because the crystalline lens or the IOL may dislocate into the anterior chamber. If there is any question of loss of zonular integrity on the basis of slit lamp evaluation, the zonules must be evaluated gonioscopically.5 Numerous clinically significant changes in the eye occur as a result. These include major intraoperative and postoperative complications in association with cataract surgery (Table 2).3
Table 2
Ocular surgical complications associated with XFS
Decentration or dislocation of the IOL Decentration of the capsular bag Capsular contraction syndrome Posterior capsular opacification Increase IOP status after cataract extraction secondary to true keratopathy
Rutner and Madonna
Clinical Care
The incidence of IOL dislocation after cataract surgery has been reported to be between 0.2% and 2.8%.4 Although there have been few reports of IOL dislocation in patients with XFS, the incidence would be expected to be much higher. One study examined 25 eyes of 22 patients with IOL dislocation and found that 44% of those patients had XFS.6 Moreover, patients with XFS have increased nuclear opacification compared with their normal peers, thereby necessitating cataract surgery.7,8 Spontaneous late dislocation of posterior chamber IOLs within the capsular bag was reported in 8 eyes of 7 patients with XFS, as with our patient. The “mean interval” from the time of original surgery to IOL dislocation was approximately 85 months.6 Despite the risks of IOL dislocation, modern phacoemulsification surgery remains the preferred method of cataract removal in patients with XFS.8 Additionally, there is some speculation that phacoemulsification may remove a source of the exfoliative material thus significantly improving aqueous outflow and IOP control.9,10 It is recommended that cataract surgery be performed earlier (in the staging of the cataract) in patients with XFS to lessen the increasing zonular instability seen with age and the increasing density of the cataractous nucleus that requires greater phacoemulsification energy.11 Increased tremulousness of the lens or phacodonesis is a clear sign of zonular instability that requires extreme care by the surgeon in placing a posterior chamber IOL in the capsular bag. Capsular tension rings, a recent addition to the surgical care of the patient with zonular instability, may be placed within the capsular bag to facilitate surgery; these rings are thought to function by providing support and circular contour to the capsular bag and by evenly distributing forces on remaining intact zonules.6 If it is felt that the posterior capsule is unable to support the IOL, then alternative fixation sites such as the ciliary sulcus or the anterior chamber or even scleral fixation should be utilized.6 Observation of phacodonesis may require stabilization of the anterior capsule by insertion of iris hooks under the anterior capsulorrhexis rim and the implantation of a polymethylmethacrylate capsular supporting ring.8,10 Capsular contraction syndrome can be circumvented by avoiding the use of flexible silicone IOLs, which can sometimes cause vaulting of the IOL optics.12 Zonular compromise may be exacerbated by post capsular opacification or capsule fibrosis and contraction.4,6 The persistent breakdown of the blood aqueous barrier in eyes with XFS may increase this compromise, further stressing the already vulnerable zonular system. One study found that 45% of patients with XFS had posterior capsular opacification (PCO) or anterior capsular opacification (ACO) within 24 months.14 Capsular tension rings, which have been shown to reduce the incidence of capsular opacification, may be indicated for this reason as well.6 Once dislocation of the IOL occurs, there are several management possibilities: observation, repositioning of the IOL, or removal of the IOL. Some advocate leaving the IOL in place under any of the following conditions:
223 1. 2. 3. 4. 5.
partial dislocation without phacodonesis advanced patient age with limited life expectancy associated serious medical condition immobile, dislocated IOL small IOL made of soft and inert material without sharp edges.15 If observation is the management choice, it is important that the patient sleep with an elevated head position to avoid contact of the IOL with the macula or optic nerve. The patient should be monitored regularly for complications such as intraocular hemorrhage, infection, uveitis, or iris or chorioretinal contusion. An IOL-induced uveitis may induce uveitic glaucoma or cystoid macular edema. In addition, retinal breaks or detachment may develop.15 Patients with IOL dislocation need to be monitored for increased IOP. Several etiologies for this increase in IOP are possible. As in the case above, a severe inflammatory reaction can be caused by the IOL coming in contact with the ciliary body producing cells and flare. Increased IOP may develop in the absence of an inflammatory response and is usually secondary to IOL-induced aqueous misdirection. Spikes in IOP have been reported to be as high as 60 mmHg6 and may not be present at initial visits. Thus, routine follow-up every 3 to 4 months is crucial to the preservation of vision.
Conclusion When cataract surgery and IOL placement are planned for a patient with XFS, it is important to assess the status of the zonules. Zonular integrity should be evaluated preoperatively via slit lamp biomicroscopy and gonioscopy looking for the presence of phacodonesis or iridodonesis. Patients who do not have adequate zonular support may experience intraoperative, early postoperative, or later postoperative IOL decentration or dislocation. Even in the absence of obvious inadequate zonular support, all patients with XFS are at risk for the development of IOL dislocation. Optometrists need to be aware that XFS is not only a precursor to glaucoma but can also increase the risk for complications during and after cataract surgery, even well past the immediate postoperative period.
References 1. Eagle RCJ Jr, Spencer WH. Lens. In: Spencer WH (ed). Ophthalmic pathology: an atlas and textbook, 4th ed. Philadelphia: WB Saunders, 1996; 394. 2. Ritch R. Exfoliation syndrome: the most common identifiable cause of open-angle glaucoma. J Glaucoma 1994;3:176-8. 3. Naumann GOH, Schlotzer-Schrehardt U, Kuchle M. Pseudoexfoliation syndrome for the comprehensive ophthalmologist. Ophthalmology 1998;105:951-68. 4. Gross JG, Kokame GT, Weinberg DV. In the bag intraocular lens dislocation. Am J Ophthalmol 2004;137:630-5.
224 5. Yanoff M, Duker JS. Ophthalmology ed 2. St. Louis, MO: Mosby, 2004 (chapt 53). 6. Jehan FS, Mamalis N, Crandall AS. Spontaneous late dislocation of intraocular lens within the capsular bag in pseudoexfoliation patients. Ophthalmology 2001;108;10:1727-31. 7. Seland JH, Chylack LT. Cataracts in the exfoliation syndrome (fibrillopathia epitheliocapsularis). Trans Ophthalmol Soc UK 1982;102:375-9. 8. Heitanen J, Kivela T, Vesti E, et al. Exfoliation syndrome in patients scheduled for cataract surgery. Acta Ophthalmol (Copenh) 1992;70:440-6. 9. Nagashima RJ. Decreased incidence of capsule complications and vitreous loss during phacoemulsification in eyes with pseudoexfoliation syndrome. J Cataract Refract Surg 2004;30:127-31. 10. Merkur A, Damji KF, Mintsioulis G, et al. Intraocular pressure decreased after phacoemulsification in patients with pseudoexfoliation syndrome. J Cataract Refract Surg 2001;27:528-32.
Optometry, Vol 78, No 5, May 2007 11. Puska P, Ahti Tarkkanen A. Exfoliation syndrome as a risk factor for cataract development. J Cataract Refract Surg 2001;27: 1992-8. 12. Bayraktar S, Altan T, Kucuksumer Y, et al. Capsular tension ring implantation after capsulorhexis in phacoemulsification of cataracts associated with pseudoexfoliation syndrome. J Cataract Refract Surg 2001;27:1620-8. 13. Werner L, Pandey SK, Apple DJ. Anterior capsule opacification; correlation of pathologic findings with clinical sequelae. Ophthalmology 2001;108:1675-81. 14. Kuchle A, Amberg A, Martus P, et al. Pseudoexfoliation syndrome and secondary cataract. Br J Ophthalmol 1997;81:862-6. 15. Chan CK, Agarwal A, Agarwal S, Agarwal A. Management of dislocated intraocular implants. Ophthalmol Clinic of North America 2001;14:681-93.
Spontaneous, bilateral intraocular lens dislocation in a patient with exfoliation syndrome Daniella Rutner, O.D., M.S., and Richard J. Madonna, O.D., M.A. Department of Clinical Science, SUNY State College of Optometry, New York, New York. KEYWORDS Glaucoma; Psuedoexfoliation; Exfoliation; Lens subluxation; Cataract; Pseudophakia; Phacodonesis; Phacoemulsification surgery
Abstract BACKGROUND: Exfoliation syndrome (XFS) is a relatively common age-related disorder characterized by the production and progressive accumulation of a fibrillar extracellular material in numerous ocular tissues and throughout the body. XFS is a known identifiable cause of open-angle glaucoma. However, because of its widespread distribution, other structures in the eye are affected. Because of weakening of the zonular apparatus and posterior capsule, and subsequent loss of support for the lens or posterior chamber intraocular lenses (IOLs), its presence must be factored into the pre- and postoperative management of persons undergoing cataract surgery. CASE REPORT: An 89-year-old white female presented with the sudden onset of decreased vision in her left eye. She had a history of uncomplicated cataract extraction and posterior chamber IOL implantation in each eye about 10 years previously. She was also known to have XFS. Examination found XFS, a dislocated posterior chamber IOL, anterior uveitis, and markedly elevated intraocular pressure. After stabilizing the eye medically, the patient presented 5 months later with the same condition in the right eye. This eye was also stabilized medically. The patient refused further treatment. CONCLUSIONS: It is imperative that the comanaging optometrist and cataract surgeon be cognizant of the presence of XFS when planning cataract surgery. However, the effects of XFS may not be seen for many years after apparently successful cataract surgery. Optometry 2007;78:220-224
Exfoliation syndrome (pseudoexfoliation syndrome, XFS, PEX, PES, or PXE) is a relatively common age-related ocular disorder that is well known to be a cause of openangle glaucoma. XFS is characterized by the production and progressive accumulation of a fibrillar extracellular material in many ocular tissues and throughout the body. It affects 4% to 6% of patients older than 60 years and as many as 8% to 35% over the age of 70.1 A higher incidence is found in certain ethnic groups as diverse as northern Scandinavians, Saudi Arabians, and Navajo Indians.1 XFS is best known as the most common identifiable cause of open-angle glau-
Corresponding author: Daniella Rutner, O.D., M.S., SUNY State College of Optometry, 33 West 42nd Street, New York, New York 10036. E-mail: [email protected]
coma, but it affects all structures in the eye.2 Additionally, XFS material has been found in skin, heart, lungs, brains, kidney, liver, and gallbladder. The significance of these deposits has not been clearly elucidated (see Table 1).3 The classic diagnostic sign of XFS is a characteristic unilateral or bilateral bull’s-eye appearance of the anterior lens surface, produced by pupillary wiping of a ring of exfoliative material from the lens surface. Occasionally, white flakes on the pupillary border of the iris may be the only subtle sign present.1 Early clinical diagnosis is made by careful slit lamp examination looking for exfoliative material on the anterior lens capsule, pupillary frill, and the zonules. In cases in which exfoliative material is not readily visible, the earliest change may be iris transillumination defects caused by loss of melanin. These transillu-
1529-1839/07/$ -see front matter © 2007 American Optometric Association. All rights reserved. doi:10.1016/j.optm.2006.12.012
Rutner and Madonna Table 1
Clinical Care
221
Ocular and systemic disease associated with XFS
Ocular disease Glaucoma Lens dislocation Blood-aqueous breakdown Pigment dispersion Iris complications Corneal endothelial decompensation Increased incidence of central retinal vein occlusion Systemic disease Densorianeural hearing loss Transient ischemic attacks Stroke Heart disease Aneurysms of the abdominal aorta
mination defects may be found in the sphincter region or throughout the iris. Increased pigment deposition on anterior segment structures such as trabecular meshwork or the existence of circular or segmental posterior synechiae, as well as poor dilation or anterior chamber melanin dispersion after dilation should also increase suspicion of XFS.4 Intraoperative lens dislocation in patients with XFS is a well-recognized condition.3,4 Less is known about the longterm consequences of XFS on the stability of posterior chamber intraocular lenses (IOLs).
Case report An 89-year-old white woman was referred for evaluation of marked decrease in visual acuity in her left eye and an increase in intraocular pressure (IOP). She was known to have moderately reduced visual acuity because of geo-
Figure 1
Retroillumination shows dislocated IOL within capsular bag.
Figure 2
Direct illumination shows dislocated IOL within capsular bag.
graphic atrophy associated with age-related macular degeneration. She had XFS diagnosed in 1988 (before cataract surgery) but had shown no elevation of IOP or sign of glaucoma since that time. She had undergone uncomplicated extracapsular cataract extraction with posterior chamber IOL implantation in both eyes about 10 years before the current visit. Presenting corrected visual acuities were 20/40 in the right eye (O.D.) and counting fingers in the left eye (O.S.). The pupils responded to light sluggishly but equally, and there was no relative afferent pupillary defect. Slit lamp evaluation showed exfoliative material at the pupillary frill in both eyes. There was microcystic edema O.S. A dislocated posterior chamber IOL within the capsular bag was noted O.S. The IOL had fallen inferiorly, but the top portion of the IOL was visible in the inferior portion of the pupil (see Figures 1 through 3). The patient denied any history of trauma or fall. Anterior chamber showed grade 1 cells and flare. IOPs were 17 mmHg in the right eye and 41 mmHg in the left eye. On 4-mirror gonioscopy, the angle was open to ciliary body in both eyes with grade 3 pigment evenly dispersed. Ultrasound B scan was performed in the office, and the retina was found to be flat and intact. In the office, she was treated with 0.5% timolol maleate/0.2% dorzolamide (Cosopt; Merck & Co. Inc., West Point, Pennsylvania) eye drops and oral acetazolamide in an effort to rapidly reduce the IOP in the left eye. With the IOP reduced to 25 mmHg, she was dismissed on topical 0.005% latanoprost (Xalatan; Pfizer Pharmaceuticals, New York, New York) at bedtime O.S. and Cosopt twice daily O.S. and told to return in 1 day.
222
Optometry, Vol 78, No 5, May 2007 and 14 mmHg O.S. The patient was prescribed Cosopt twice daily in both eyes (OU) and Xalatan at bedtime OU. One week later, the visual acuities were a 400 letter at 4 inches O.D. and a 400 letter at 8 inches O.S. Slit lamp examination was unchanged, and IOPs were 17 mmHg O.D. and 17 mmHg O.S. Refraction improved vision to 20/400 O.D. with a ⫹9.00 diopter (D) sphere, whereas an objective refraction of ⫹12.00 D sphere did not improve vision OS. The patient decided she was not interested in surgery because she felt she could accomplish her activities of daily living with the prescribed spectacle correction.
Discussion
Figure 3
Undilated view shows exfoliative material on pupillary margin with free-floating zonules visible through the pupil.
The patient could not return the next day, but instead was seen 3 days later. Visual acuities remained 20/40 O.D. and counting fingers O.S. IOPs were now reduced to 15 mmHg O.D. and 10 mmHg O.S. She was told to continue her current eye drop regimen and asked to return in 1 week. The patient actually returned in 2 weeks with no change in visual acuity, and IOPs were well controlled at 14 mmHg O.D. and 15 mmHg O.S. Xalatan use was discontinued, and the patient was told to continue taking Cosopt twice daily O.S. and return 2 weeks later. At the 2-week visit, visual acuities remained unchanged, and IOPs were 14 mmHg O.D. and 26 mmHg O.S. At this time, the patient was counseled regarding surgery to reposition the IOL. She preferred no surgical intervention. She was instructed to restart taking Xalatan at bedtime O.S. and continue Cosopt twice a day O.S. and was asked to return in 2 weeks. At that visit, visual acuities remained stable, and IOPs were 16 mmHg O.D. and 14 mmHg O.S. Over the course of the next 2 months, there was no change in her clinical condition, and the patient reiterated that she was not interested in surgery. The patient returned urgently 1 month later (about 4 months after the initial visit) complaining of a marked decrease in vision in her right eye. Visual acuities were hand motion O.D. and counting fingers O.S. Slit lamp evaluation now found dislocated IOLs in both eyes. The appearance of the right eye was very similar to the appearance of the left eye at the initial presentation. IOPs were 32 mmHg O.D.
Exfoliation syndrome is a relatively common ocular disorder. The exact cause of this condition remains unknown. Speculation is that there is an overproduction of extracellular matrix material by lens, iris, and ciliary epithelial cells alone or in combination with poor resorption of this material. The exfoliative material then accumulates on the surfaces of structures that come in contact with aqueous, including zonular fibers, iris, ciliary body, trabecular meshwork, and the corneal endothelium. Because of its widespread distribution in the eye, it can cause weakening of the zonular apparatus and posterior capsule and subsequent loss of support for the crystalline lens or posterior chamber IOL. Zonular dysfunction, marked by increased friability and decreased tensile strength, may lead to lens or IOL dislocation.3,4 Exfoliative material has been shown to disrupt the zonules at 3 levels: (1) at the origin of the ciliary body where they are anchored, (2) in the pars plicata of the ciliary body where they pass alongside the ciliary processes, and (3) at their attachment to the anterior lens capsule.4 When cataract surgery and IOL implantation is planned in patients with XFS, the status of the zonules must be evaluated carefully. The presence of phacodonesis or iridodonesis indicates reduced zonular integrity and the potential for poor zonular support of the IOL. Thus, caution needs to be exercised during routine dilation because the crystalline lens or the IOL may dislocate into the anterior chamber. If there is any question of loss of zonular integrity on the basis of slit lamp evaluation, the zonules must be evaluated gonioscopically.5 Numerous clinically significant changes in the eye occur as a result. These include major intraoperative and postoperative complications in association with cataract surgery (Table 2).3
Table 2
Ocular surgical complications associated with XFS
Decentration or dislocation of the IOL Decentration of the capsular bag Capsular contraction syndrome Posterior capsular opacification Increase IOP status after cataract extraction secondary to true keratopathy
Rutner and Madonna
Clinical Care
The incidence of IOL dislocation after cataract surgery has been reported to be between 0.2% and 2.8%.4 Although there have been few reports of IOL dislocation in patients with XFS, the incidence would be expected to be much higher. One study examined 25 eyes of 22 patients with IOL dislocation and found that 44% of those patients had XFS.6 Moreover, patients with XFS have increased nuclear opacification compared with their normal peers, thereby necessitating cataract surgery.7,8 Spontaneous late dislocation of posterior chamber IOLs within the capsular bag was reported in 8 eyes of 7 patients with XFS, as with our patient. The “mean interval” from the time of original surgery to IOL dislocation was approximately 85 months.6 Despite the risks of IOL dislocation, modern phacoemulsification surgery remains the preferred method of cataract removal in patients with XFS.8 Additionally, there is some speculation that phacoemulsification may remove a source of the exfoliative material thus significantly improving aqueous outflow and IOP control.9,10 It is recommended that cataract surgery be performed earlier (in the staging of the cataract) in patients with XFS to lessen the increasing zonular instability seen with age and the increasing density of the cataractous nucleus that requires greater phacoemulsification energy.11 Increased tremulousness of the lens or phacodonesis is a clear sign of zonular instability that requires extreme care by the surgeon in placing a posterior chamber IOL in the capsular bag. Capsular tension rings, a recent addition to the surgical care of the patient with zonular instability, may be placed within the capsular bag to facilitate surgery; these rings are thought to function by providing support and circular contour to the capsular bag and by evenly distributing forces on remaining intact zonules.6 If it is felt that the posterior capsule is unable to support the IOL, then alternative fixation sites such as the ciliary sulcus or the anterior chamber or even scleral fixation should be utilized.6 Observation of phacodonesis may require stabilization of the anterior capsule by insertion of iris hooks under the anterior capsulorrhexis rim and the implantation of a polymethylmethacrylate capsular supporting ring.8,10 Capsular contraction syndrome can be circumvented by avoiding the use of flexible silicone IOLs, which can sometimes cause vaulting of the IOL optics.12 Zonular compromise may be exacerbated by post capsular opacification or capsule fibrosis and contraction.4,6 The persistent breakdown of the blood aqueous barrier in eyes with XFS may increase this compromise, further stressing the already vulnerable zonular system. One study found that 45% of patients with XFS had posterior capsular opacification (PCO) or anterior capsular opacification (ACO) within 24 months.14 Capsular tension rings, which have been shown to reduce the incidence of capsular opacification, may be indicated for this reason as well.6 Once dislocation of the IOL occurs, there are several management possibilities: observation, repositioning of the IOL, or removal of the IOL. Some advocate leaving the IOL in place under any of the following conditions:
223 1. 2. 3. 4. 5.
partial dislocation without phacodonesis advanced patient age with limited life expectancy associated serious medical condition immobile, dislocated IOL small IOL made of soft and inert material without sharp edges.15 If observation is the management choice, it is important that the patient sleep with an elevated head position to avoid contact of the IOL with the macula or optic nerve. The patient should be monitored regularly for complications such as intraocular hemorrhage, infection, uveitis, or iris or chorioretinal contusion. An IOL-induced uveitis may induce uveitic glaucoma or cystoid macular edema. In addition, retinal breaks or detachment may develop.15 Patients with IOL dislocation need to be monitored for increased IOP. Several etiologies for this increase in IOP are possible. As in the case above, a severe inflammatory reaction can be caused by the IOL coming in contact with the ciliary body producing cells and flare. Increased IOP may develop in the absence of an inflammatory response and is usually secondary to IOL-induced aqueous misdirection. Spikes in IOP have been reported to be as high as 60 mmHg6 and may not be present at initial visits. Thus, routine follow-up every 3 to 4 months is crucial to the preservation of vision.
Conclusion When cataract surgery and IOL placement are planned for a patient with XFS, it is important to assess the status of the zonules. Zonular integrity should be evaluated preoperatively via slit lamp biomicroscopy and gonioscopy looking for the presence of phacodonesis or iridodonesis. Patients who do not have adequate zonular support may experience intraoperative, early postoperative, or later postoperative IOL decentration or dislocation. Even in the absence of obvious inadequate zonular support, all patients with XFS are at risk for the development of IOL dislocation. Optometrists need to be aware that XFS is not only a precursor to glaucoma but can also increase the risk for complications during and after cataract surgery, even well past the immediate postoperative period.
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