Manage ment of Siderosis Bulbi due to a Retained Ironcontaining Intraocular foreign Body SCOTT R. SNEED, MD, THOMAS A. WEINGEIST, MD, PhD Abstract: The authors report their experience in managing 14 cases of siderosis bulbi secondary to a retained iron-containing intraocular foreign body (IOFB). The IOFB was removed in 12 of the 14 eyes. The IOFB was removed with a sclerotomy and external magnet (5 eyes), a pars plana vitrectomy (PPV) and intraocular forceps (5 eyes), a PPV and intraocular magnet (1 eye), and a PPV with aspiration using the suction mode of the vitrectomy instrument (1 eye). A siderotic cataract developed in 11 eyes and cataract extraction resulted in postoperative visual acuity ranging from 20/15 to 20/40. The most recent siderotic cataracts have been managed with cataract extraction and posterior chamber intraocular lens (PC IOL) implantation. No patient in this series experienced visual deterioration after receiving medical attention. The current management of siderosis bulbi is discussed. Ophthalmology 1990; 97:375-379
Siderosis bulbi may develop in an eye with a retained iron-containing intraocular foreign body (IOFB). Classic clinical findings in siderosis bulbi include iris heterochromia, pupillary mydriasis, cataract formation, retinal pigmentary degeneration, and an electroretinographic response which is initially hypernormal, but gradually diminishes with progressive siderotic degeneration. 1 Recent technologic advances have increased the options available for managing these cases. Pars plana vitrectomy facilitates the extraction of posteriorly located foreign bodies and the removal of metallic foreign bodies which have lost their magnetic property. Extracapsular cataract extraction using phacoemulsification or nuclear expression with posterior chamber intraocular lens (PC IOL) implantation may be the techniques of choice for visual rehabilitation of eyes with siderotic cataracts. Based on our experience
in managing 14 cases of siderosis bulbi, we present the indications and techniques for removal of iron-containing IOFBs and cataract extraction in eyes with siderotic cataracts.
MATERIALS AND METHODS The medical records of all patients seen at the University of Iowa Hospitals and Clinics from August 1968 to January 1989 with a history of siderosis bulbi secondary to a retained IOFB were retrospectively analyzed. The clinical course of 13 patients (14 eyes) with the diagnosis of siderosis bulbi secondary to a retained IOFB which had 6 months or more of follow-up was reviewed.
RESULTS Originally received: June 15, 1989. Revision accepted: August 9, 1989. From the Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City. Dr. Sneed is currently affiliated with theW. K. Kellogg Eye Center, University of Michigan, Ann Arbor. Supported in part by the Retina Research Fund, University of Iowa, and an unrestricted grant from the Research to Prevent Blindness, Inc, New York, New York. Reprint requests to Thomas A. Weingeist, MD, PhD, Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City, lA 52242.
All eyes showed clinical manifestations of ocular siderosis including iris heterochromia, pupillary mydriasis, cataract, retinal pigment epithelial degeneration, and/or a decreased electroretinographic response. One patient had bilateral retained IOFBs (patient 3). The demographic features of all cases are listed in Table 1. Nine patients had a history consistent with a metallic foreign body injury; one child was watching his father chop wood (patient 4) when he apparently sustained the foreign body injury; one patient was running a power lawn 375
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mower when he was struck by the foreign body (patient 2); and two patients had no history of a foreign body injury (patients 9 and 13). The length of time that elapsed between the foreign body injury and presentation with siderosis ranged from 3 weeks to 40 months in those cases where a history of an injury could be elicited. Three eyes (patients 6, 10, and 11) demonstrated optic disc hyperemia. Fluorescein angiography in two of these eyes showed disc staining. Flicker fusion in two eyes was lower than in the normal fellow eye; however, Goldmann visual field testing failed to demonstrate an enlarged blind spot. One eye showed gradual resolution of disc swelling 22 months after removal of the IOFB (patient 6). No significant change in disc hyperemia has been noted in the 6 months after removal of the IOFB in patient 10, or after 6 months in patient 11 where the IOFB was not removed. Hypotony, vitreous inflammation, and other causes of optic disc hyperemia were absent in all three cases. Dark adaptation was increased from 0.5 to 3.0 log units in eight of the nine eyes tested, and was normal in the eye with the lenticular foreign body. The electroretinogram (ERG) was depressed in 12 eyes and was normal in the eye with the lenticular foreign body and also in patient l. The IOFB was removed in patient 1 because of the iris heterochromia which suggested early siderosis bulbi. The IOFB was removed in 12 eyes. A sclerotomy with IOFB removal using an external magnet was performed in five eyes and the IOFB was removed with a pars plana vitrectomy (PPV) and intraocular forceps in five eyes. The foreign body was removed with a PPV and an intraocular magnet in one eye and with aspiration using the suction/ cutting vitrectomy instrument in one eye. A siderotic cataract was present at the initial evaluation in seven eyes and developed between 12 and 24 months after the foreign body removal in three eyes. A siderotic cataract developed in the eye harboring the intralenticular foreign body 2 months after the foreign body injury. Thus, a siderotic cataract developed in 11 eyes and was removed in all 11 eyes. A pars plana approach was used in seven eyes. An anterior approach using a suction and cutting instrument was performed in two eyes. More recently, phacoemulsification with PC IOL implantation was performed in one eye and extracapsular cataract extraction with PC IOL implantation was performed in one eye. One intraoperative complication occurred in this series (see Case Report section). In this case, the IOFB was located in the inferior peripheral vitreous. As the foreign body was approached with the vitrectomy instrument, it was inadvertently pulled toward the suction port of the vitrectomy probe. The cutting portion of the vitrectomy instrument closed on an edge of the foreign body and catapulted the foreign body anteriorly away from the vitrectomy instrument. Careful inspection using indirect ophthalmoscopy with scleral indentation failed to show the location of the foreign body.
CASE REPORT A 32-year-o1d white man (patient 11) was hammering a steel object without wearing safety glasses in May 1988 when he felt
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a foreign body sensation in his left eye. He irrigated his eye and thought that the foreign body was washed from his eye. He was asymptomatic until August 1988 when he noticed gradually decreasing vision. He presented to The University oflowa Hospitals and Clinics on November 3, 1988, with visual acuity of 20/20 in the right eye and 20/50 in the left eye. Anisocoria was present with the left pupil larger than the right (Fig 1). The direct and consensual response to light in the left pupil was decreased as compared with the right pupil. There was no afferent pupillary defect. Results of external examination showed iris. heterochromia with a darker rust-colored left iris (Fig 1). Results of slit-lamp examination of the right eye were normal. In the left eye, there was a full-thickness inferonasal corneal scar and a hole in the iris (Fig 2). Results of examination of the lens showed a diffuse posterior subcapsular cataract, a wedge-shaped cortical cataract inferonasally, and anterior brownish subcapsular deposits (Fig 2). Gonioscopy was normal. Intraocular pressures were 18/16 mmHg. Results of dilated fundus examination of the right eye were normal. The retina was attached in the left eye and the optic disc was swollen (Fig 3). No vitreous inflammation could be identified. The macula was normal. Retinal pigment epithelial mottling and hypopigmentation were present inferiorly (Fig 4). A small IOFB was visible in the inferonasal peripheral vitreous. Dark adaptation in the right eye was normal but elevated 0.5 to 1 log unit in the left eye. Photopic and scotopic electroretinographic responses were normal in the right eye and were markedly decreased in the left. Echography confirmed the presence of the intravitreal foreign body. The left optic disc stained when examined by fluorescein angiography (Fig 5). On November 15, 1988, an extracapsular cataract extraction, PC IOL implantation, and pars plana vitrectomy were performed on the left eye. As the foreign body was approached with the vitreous instrument, the foreign body was inadvertantly pulled toward the suction port of the vitrectomy probe. The cutting portion of the vitrectomy instrument closed on an edge of the foreign body, and catapulted anteriorly away from the vitrectomy instrument. The foreign body could not be identified with the vitreous instruments or using the indirect ophthalmoscope with scleral indentation. The foreign body is most likely located on the pars plicata or just behind the iris. Results of histopathologic examination of the anterior lens capsule showed lens epithelial staining consistent with iron deposition (Fig 6). The ERG and optic disc hyperemia have remained unchanged 6 months postoperatively. Visual acuity in the left eye was 20/ 50 in the presence of a posterior subcapsular opacification. A Y AG caps ulotomy was performed on April 17, 1989, and visual acuity improved to 20/20 within l week.
DISCUSSION Siderosis bulbi which is characterized by iris heterochromia, pupillary mydriasis, cataract, retinal pigmentary changes, and occasionally optic disc hyperemia may develop in eyes that harbor iron-containing intraocular foreign bodies. Siderosis seems to be more advanced when the foreign body is located in the posterior segment. 1 Foreign bodies tend to be better tolerated when located in the anterior chamber or imbedded in the lens. Siderotic changes have been reported to occur from 18 days2 to 8 years 3 after the injury. The natural course of a retained IOFB varies widely: small IOFBs may be completely resorbed4 ; the foreign body may become encapsulated;
Vol
-...] -...]
27/M 11/M 31/M/OS OD 8/M
44/M
24/M
30/M
42/M
23/M 39/M
32/M 30/M 21/M
1 2 3
5
6
7
8
9 10
11 12 13
6 mas 10 mas Unknown
Unknown 6 mas
2 mas
40 mas
3 wks
5 mas
5 wks 2 mas 6 wks 6 wks 10 mas
Time Between Injury and Presentation
Cornea Not identified Cornea
Cornea Cornea
Cornea
Cornea
Cornea
Cornea
Not identified Not identified Sclera Cornea Cornea
Entrance Wound
Yes Yes Yes
Yes Yes
Yes
Yes
Yes
Yes
Yes No No No No
Iris Heterochromia
Yes Yes Yes
Yes Yes
Yes
Yes
Yes
Yes
No No No Yes Yes
Cataract
Inferior vitreous On inferior retina Inferior pars plana
Inferior pars plana Inferior vitreous
Inferior vitreous
Inferior vitreous
Inferior vitreous
Ciliary body
Inferior vitreous Posterior vitreous On nasal retina Lens Inferior pars plana
Location of IOFB
CF
-
HM 20/500
20/750
20/4000
20/30
20/30
20/20 20/80 20/25 20/400 20/30
Before IOFB Removal
20/50 HM CF
HM 20/500
20/750
20/4000
CF
HM
20/400 HM
-
Before CE
20/20 20/25 20/20
20/15 20/40
20/40
20/30
20/20
20/25
20/20 20/30 20/25 20/20 20/25
Final
+ + +
+ +
+
+
+
+
+
Normal
+ +
Normal
ERG
Not performed
t 0.5-1.0 LU t 2 LU
Not performed
t3 LU
Not performed
t 1.5 LU
t 1LU
t 1LU
Not performed t 1LU t 0.5 LU Normal Not performed
Dark Adaptation
6 9 15
24 6
11
84
40
72
28 37
33 16
Follow-up (mas)
RIOFB (E. magnet) PPV, RIOFB (Ocutome) PPV, RIOFB (I. magnet) PPV, PPL, RIOFB (forceps) (1) RIOFB (E. magnet), SBP (2) PPV, PPL, (12 mas after RIOFB) (1) RIOFB (E. magnet) (2) PPV, PPL, (16 mas after RIOFB) (1) PPV, RIOFB (E. magnet) (2) Lensectomy (23 mas after RIOFB) (3) SBP (24 mas after lensectomy) (4) PPV, AFX8 (1 mo after SBP) (1) PPV, PPL, RIOFB (forceps) (2) SBP (1 mo after RIOFB) PPV, PPL, SBP, AFX8, RIOFB (forceps) PPV, PPL, RIOFB (forceps) PPV, Phaco, PCIOL, RIOFB (E. magnet) PPV, ECCE, PCIOL Lensectomy (1) PPV, PPL, SBP, RIOFB (forceps) (2) SBP revision (2 mas after no. 1) (3) SBP revision (4 mas after no. 2)
Surgery
IOFB = intraocular foreign body; CE = cataract extraction; CF = count fingers; ERG = electroretinogram; RIOFB = remove intraocular foreign body; E. magnet = external magnet; LU = log units; PPV = pars plana vitrectomy, 1. magnet = intraocular magnet; OS = left eye; OD = right eye; PPL = pars plana lensectomy; HM = hand motions; SBP = scleral buckling procedure; AFX8 = air-ftuid exchange; Phaco = phacoemulsification; PCIOL = posterior chamber intraocular lens; ECCE = extracapsular cataract extraction.
4
Age (yrs)/Sex
Patient No.
Visual Acuity
Table 1. Management of Siderosis Bulbi
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Fig I. Top left, iris heterochromia. Normal right eye. The left iris is darker than the right and there is a full-thickness hole in the iris at the 7o'clock position. Fig 2. Top right, slit lamp photograph of the left eye shows the corneal scar, the hole in the iris, and the brownish rust-colored anterior subcapsular lenticular deposits. Fig 3. Second row left, fundus photograph of the left eye demonstrates the swollen optic disc. The hazy view is due to the posterior subcapsular cataract. Fig 4. Second row right, fundus photograph of the inferior periphery of the left eye shows retinal pigment epithelial mottling and hypopigmentation adjacent to the more anteriorly located intraocular foreign body. Fig 5. Third row, late phase fluorescein angiogram of the left fundus demonstrates fluorescein leakage from the optic disc. Fig 6. Bottom left, histopathologic section of the anterior lens capsule of the left eye removed at the time of cataract extraction shows the intraepithelial brown iron granules and the basement membrane which stains purple (periodic acid-Schiff; original magnification, XIOO). Bottom right, histopathologic specimen of the anterior lens capsule demonstrates the presence of iron within the lens epithelium which stains blue (iron stain; original magnification, X I 00). (Figures used with permission from The University of Iowa: Pathology of the EyeAn Interactive Videodisc Program.)
the siderotic changes may stabilize or regress 5•6; the foreign body may lose its magnetic properties or become radiolucent to x-rays6 ; or progressive siderotic degeneration may occur. Patients with a clinical diagnosis of siderosis bulbi may present with iris heterochromia, pupillary mydriasis, chronic uveitis/iritis, or decreased vision secondary to cataract or less often due to retinal degenerative changes. To our knowledge, optic disc hyperemia has not been described previously in patients with siderosis bulbi. The etiology of this finding is unclear although other causes
378
of optic disc edema (hypotony or vitreous inflammation) were not present. One might speculate that this represents a toxic effect on the optic nerve secondary to the iron, because the optic disc hyperemia disappeared after the IOFB was removed in 1 patient (patient 6). Long-term follow-up of the optic disc hyperemia in the other two patients (patients 10 and 11) using serial flicker fusion, visual acuity, and visual field testing is currently being pursued. An occult foreign body in the inferior anterior chamber angle is suggested by the presence of an inferior wedge-
SNEED AND WEINGEIST
shaped area of corneal edema. A full-thickness corneal scar, an iris defect, or the characteristic anterior subcapsular brownish lens opacities are clues that the eye contains an occult IOFB. The presence of an occult IOFB also should be entertained in eyes with unexplained unilateral iritis. The diagnosis of a retained IOFB is often made ophthalmoscopically or by slit-lamp examination. Gonioscopy will detect a foreign body in the anterior chamber angle. Slit-lamp examination after dilation may detect a lenticular foreign body. Results of dilated fundus examination can show a foreign body in the vitreous or on the retina if vitreous hemorrhage or a dense cataract is not present. The foreign body is often located inferiorly and if peripherally located is best visualized with scleral indentation. If the suspected IOFB is not seen clinically, further evaluation may be necessary. Plain film x-rays with the patient looking up and down may show a radio-opaque foreign body which changes position with eye movement. Computed tomographic scanning with thin cuts is often helpful in foreign body localization. Echography is a sensitive method in detecting the presence and location of an IOFB. A metallic foreign body localizer also can be used to determine the presence and location of an IOFB. Numerous management options are available once the diagnosis of siderosis bulbi secondary to a retained IOFB has been made. All patients should have a baseline ERG. Dark adaptation testing may be helpful. Foreign bodies encapsulated in the posterior segment are often difficult to remove, and siderotic changes may remain stable once encapsulation occurs. Serial evaluation with ERG testing every 2 to 3 months may be appropriate during the initial management of these eyes. If the ERG remains stable, the patient can continue to be observed with gradually increasing intervals between follow-up examinations. If deterioration of the ERG is demonstrated, the foreign body should be removed. Small foreign bodies located in the anterior segment also may be observed with serial ERGs. Removal of the IOFB should be strongly entertained in eyes with diminished ERGs and a mobile foreign body in the vitreous or a nonencapsulated foreign body on the retina. An external sclerotomy with removal using an external magnet may be successful in anteriorly located magnetic foreign bodies. The location of the sclerotomy can be marked externally on the sclera using scleral indentation, much like localizing a retinal tear in retinal reattachment surgery. Alternatively, a metallic foreign body localizer may be used when the foreign body cannot be visualized. A pars plana vitrectomy and removal with an intraocular magnet may be preferred for posteriorly located magnetic IOFBs. Iron-containing foreign bodies may lose their magnetic properties over time and a pars plana vitrectomy with removal using intraocular forceps may be necessary. A posteriorly located encapsulated IOFB is often best managed with a pars plana vitrectomy. Vitreous attachments to the capsule are severed and the capsule is then incised using a sharp instrument such as a myringotomy blade or a 20-guage needle. The foreign body is then removed with either an intraocular· magnet
•
SIDEROSIS BULBI
or intraocular forceps. If the IOFB is fragile and fragments easily, removal using the suction mode of the vitrectomy probe or the aspiration needle may facilitate removal after the vitreous has been excised from the foreign body. The visual potential in eyes with siderosis bulbi may be excellent if the siderotic changes stabilize or improve, and if the optic nerve and macula have not been injured. Vision may be very good even in eyes with a half-normal ERG response. Visual acuity ranged from 20/15 to 20/ 40 in our patients over the follow-up period. Schocket et al 7 and Talamo et al 8 described separate cases of stabilized siderosis and visual acuity of 20/30 and 20/20, respectively, after removal of the foreign body and the siderotic cataract. A siderotic cataract may limit the patient's vision and/ or the ophthalmologist's view of the foreign body. These cataracts are not reversible even after the IOFB has been removed and cataract extraction may be required to improve visual acuity. We initially managed these cataracts with a pars plana lensectomy or with an anterior suction/ cutting approach. However, since the visual potential in these eyes is often excellent, we now prefer a combined extracapsular cataract extraction using nuclear expression or phacoemulsifi.cation with PC IOL implantation and simultaneous removal of the IOFB in older patients. Lens aspiration leaving an intact posterior capsule is appropriate in removing siderotic cataracts when they develop in younger patients. Siderosis bulbi is not commonly seen, but may develop in eyes with retained iron-containing IOFBs. The visual potential in eyes with siderosis bulbi is often excellent, and advances in vitreous surgery and cataract extraction have improved the visual rehabilitation in many of these eyes. Intraocular lens implantation has eliminated the need for aphakic contact lens correction in some eyes after cataract extraction. Although the foreign body is most often surgically removed, in some instances it may be left within the eye. In these cases, close follow-up with serial ERG evaluation is recommended.
REFERENCES 1. Duke-Elder S, ed. System of Ophthalmology. VoL XIV: Injuries. Pt. 1: Mechanical Injuries, St. Louis: CV Mosby, 1972; 525-44. 2. Davidson M. Siderosis bulbi. Am J Ophthalmol1933; 16:331-5. 3. Eisenberg 0. Beitrage zur Kenntisrder Siderosis bulbi [lnaug. Diss.]. Giessen, 1901. As cited in: Duke-Elder S, ed. System of Ophthalmology. VoL XIV: Injuries. Pt. 1: Mechanical Injuries. St. Louis: CV Mosby, 1972; 532. 4. Begle HL. Perforating injuries of the eye by small steel fragments. Am J Ophthalmol1929; 12:970-7. 5. Braendstrup P. Two cases of temporary siderosis bulbi with spontaneous resorption and without impairment of function. Acta Ophthalmol 1944; 22:311-6. 6. Casali A. Due casi di siderosi oculare. Ann di Ottal 1910; 39:572607. 7. Schocket SS, Lakhanpal V, Varma SO. Siderosis from a retained intraocular stone. Retina 1981; 1:201-7. 8. Talamo JH, Topping TM, Maumenee AE, Green WR. Ultrastructural studies of cornea, iris and lens in a case of siderosis bulbi. Ophthalmology 1985; 92:1675-80.
379
Siderosis bulbi may develop in an eye with a retained iron-containing intraocular foreign body (IOFB). Classic clinical findings in siderosis bulbi include iris heterochromia, pupillary mydriasis, cataract formation, retinal pigmentary degeneration, and an electroretinographic response which is initially hypernormal, but gradually diminishes with progressive siderotic degeneration. 1 Recent technologic advances have increased the options available for managing these cases. Pars plana vitrectomy facilitates the extraction of posteriorly located foreign bodies and the removal of metallic foreign bodies which have lost their magnetic property. Extracapsular cataract extraction using phacoemulsification or nuclear expression with posterior chamber intraocular lens (PC IOL) implantation may be the techniques of choice for visual rehabilitation of eyes with siderotic cataracts. Based on our experience
in managing 14 cases of siderosis bulbi, we present the indications and techniques for removal of iron-containing IOFBs and cataract extraction in eyes with siderotic cataracts.
MATERIALS AND METHODS The medical records of all patients seen at the University of Iowa Hospitals and Clinics from August 1968 to January 1989 with a history of siderosis bulbi secondary to a retained IOFB were retrospectively analyzed. The clinical course of 13 patients (14 eyes) with the diagnosis of siderosis bulbi secondary to a retained IOFB which had 6 months or more of follow-up was reviewed.
RESULTS Originally received: June 15, 1989. Revision accepted: August 9, 1989. From the Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City. Dr. Sneed is currently affiliated with theW. K. Kellogg Eye Center, University of Michigan, Ann Arbor. Supported in part by the Retina Research Fund, University of Iowa, and an unrestricted grant from the Research to Prevent Blindness, Inc, New York, New York. Reprint requests to Thomas A. Weingeist, MD, PhD, Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City, lA 52242.
All eyes showed clinical manifestations of ocular siderosis including iris heterochromia, pupillary mydriasis, cataract, retinal pigment epithelial degeneration, and/or a decreased electroretinographic response. One patient had bilateral retained IOFBs (patient 3). The demographic features of all cases are listed in Table 1. Nine patients had a history consistent with a metallic foreign body injury; one child was watching his father chop wood (patient 4) when he apparently sustained the foreign body injury; one patient was running a power lawn 375
OPHTHALMOLOGY
•
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mower when he was struck by the foreign body (patient 2); and two patients had no history of a foreign body injury (patients 9 and 13). The length of time that elapsed between the foreign body injury and presentation with siderosis ranged from 3 weeks to 40 months in those cases where a history of an injury could be elicited. Three eyes (patients 6, 10, and 11) demonstrated optic disc hyperemia. Fluorescein angiography in two of these eyes showed disc staining. Flicker fusion in two eyes was lower than in the normal fellow eye; however, Goldmann visual field testing failed to demonstrate an enlarged blind spot. One eye showed gradual resolution of disc swelling 22 months after removal of the IOFB (patient 6). No significant change in disc hyperemia has been noted in the 6 months after removal of the IOFB in patient 10, or after 6 months in patient 11 where the IOFB was not removed. Hypotony, vitreous inflammation, and other causes of optic disc hyperemia were absent in all three cases. Dark adaptation was increased from 0.5 to 3.0 log units in eight of the nine eyes tested, and was normal in the eye with the lenticular foreign body. The electroretinogram (ERG) was depressed in 12 eyes and was normal in the eye with the lenticular foreign body and also in patient l. The IOFB was removed in patient 1 because of the iris heterochromia which suggested early siderosis bulbi. The IOFB was removed in 12 eyes. A sclerotomy with IOFB removal using an external magnet was performed in five eyes and the IOFB was removed with a pars plana vitrectomy (PPV) and intraocular forceps in five eyes. The foreign body was removed with a PPV and an intraocular magnet in one eye and with aspiration using the suction/ cutting vitrectomy instrument in one eye. A siderotic cataract was present at the initial evaluation in seven eyes and developed between 12 and 24 months after the foreign body removal in three eyes. A siderotic cataract developed in the eye harboring the intralenticular foreign body 2 months after the foreign body injury. Thus, a siderotic cataract developed in 11 eyes and was removed in all 11 eyes. A pars plana approach was used in seven eyes. An anterior approach using a suction and cutting instrument was performed in two eyes. More recently, phacoemulsification with PC IOL implantation was performed in one eye and extracapsular cataract extraction with PC IOL implantation was performed in one eye. One intraoperative complication occurred in this series (see Case Report section). In this case, the IOFB was located in the inferior peripheral vitreous. As the foreign body was approached with the vitrectomy instrument, it was inadvertently pulled toward the suction port of the vitrectomy probe. The cutting portion of the vitrectomy instrument closed on an edge of the foreign body and catapulted the foreign body anteriorly away from the vitrectomy instrument. Careful inspection using indirect ophthalmoscopy with scleral indentation failed to show the location of the foreign body.
CASE REPORT A 32-year-o1d white man (patient 11) was hammering a steel object without wearing safety glasses in May 1988 when he felt
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a foreign body sensation in his left eye. He irrigated his eye and thought that the foreign body was washed from his eye. He was asymptomatic until August 1988 when he noticed gradually decreasing vision. He presented to The University oflowa Hospitals and Clinics on November 3, 1988, with visual acuity of 20/20 in the right eye and 20/50 in the left eye. Anisocoria was present with the left pupil larger than the right (Fig 1). The direct and consensual response to light in the left pupil was decreased as compared with the right pupil. There was no afferent pupillary defect. Results of external examination showed iris. heterochromia with a darker rust-colored left iris (Fig 1). Results of slit-lamp examination of the right eye were normal. In the left eye, there was a full-thickness inferonasal corneal scar and a hole in the iris (Fig 2). Results of examination of the lens showed a diffuse posterior subcapsular cataract, a wedge-shaped cortical cataract inferonasally, and anterior brownish subcapsular deposits (Fig 2). Gonioscopy was normal. Intraocular pressures were 18/16 mmHg. Results of dilated fundus examination of the right eye were normal. The retina was attached in the left eye and the optic disc was swollen (Fig 3). No vitreous inflammation could be identified. The macula was normal. Retinal pigment epithelial mottling and hypopigmentation were present inferiorly (Fig 4). A small IOFB was visible in the inferonasal peripheral vitreous. Dark adaptation in the right eye was normal but elevated 0.5 to 1 log unit in the left eye. Photopic and scotopic electroretinographic responses were normal in the right eye and were markedly decreased in the left. Echography confirmed the presence of the intravitreal foreign body. The left optic disc stained when examined by fluorescein angiography (Fig 5). On November 15, 1988, an extracapsular cataract extraction, PC IOL implantation, and pars plana vitrectomy were performed on the left eye. As the foreign body was approached with the vitreous instrument, the foreign body was inadvertantly pulled toward the suction port of the vitrectomy probe. The cutting portion of the vitrectomy instrument closed on an edge of the foreign body, and catapulted anteriorly away from the vitrectomy instrument. The foreign body could not be identified with the vitreous instruments or using the indirect ophthalmoscope with scleral indentation. The foreign body is most likely located on the pars plicata or just behind the iris. Results of histopathologic examination of the anterior lens capsule showed lens epithelial staining consistent with iron deposition (Fig 6). The ERG and optic disc hyperemia have remained unchanged 6 months postoperatively. Visual acuity in the left eye was 20/ 50 in the presence of a posterior subcapsular opacification. A Y AG caps ulotomy was performed on April 17, 1989, and visual acuity improved to 20/20 within l week.
DISCUSSION Siderosis bulbi which is characterized by iris heterochromia, pupillary mydriasis, cataract, retinal pigmentary changes, and occasionally optic disc hyperemia may develop in eyes that harbor iron-containing intraocular foreign bodies. Siderosis seems to be more advanced when the foreign body is located in the posterior segment. 1 Foreign bodies tend to be better tolerated when located in the anterior chamber or imbedded in the lens. Siderotic changes have been reported to occur from 18 days2 to 8 years 3 after the injury. The natural course of a retained IOFB varies widely: small IOFBs may be completely resorbed4 ; the foreign body may become encapsulated;
Vol
-...] -...]
27/M 11/M 31/M/OS OD 8/M
44/M
24/M
30/M
42/M
23/M 39/M
32/M 30/M 21/M
1 2 3
5
6
7
8
9 10
11 12 13
6 mas 10 mas Unknown
Unknown 6 mas
2 mas
40 mas
3 wks
5 mas
5 wks 2 mas 6 wks 6 wks 10 mas
Time Between Injury and Presentation
Cornea Not identified Cornea
Cornea Cornea
Cornea
Cornea
Cornea
Cornea
Not identified Not identified Sclera Cornea Cornea
Entrance Wound
Yes Yes Yes
Yes Yes
Yes
Yes
Yes
Yes
Yes No No No No
Iris Heterochromia
Yes Yes Yes
Yes Yes
Yes
Yes
Yes
Yes
No No No Yes Yes
Cataract
Inferior vitreous On inferior retina Inferior pars plana
Inferior pars plana Inferior vitreous
Inferior vitreous
Inferior vitreous
Inferior vitreous
Ciliary body
Inferior vitreous Posterior vitreous On nasal retina Lens Inferior pars plana
Location of IOFB
CF
-
HM 20/500
20/750
20/4000
20/30
20/30
20/20 20/80 20/25 20/400 20/30
Before IOFB Removal
20/50 HM CF
HM 20/500
20/750
20/4000
CF
HM
20/400 HM
-
Before CE
20/20 20/25 20/20
20/15 20/40
20/40
20/30
20/20
20/25
20/20 20/30 20/25 20/20 20/25
Final
+ + +
+ +
+
+
+
+
+
Normal
+ +
Normal
ERG
Not performed
t 0.5-1.0 LU t 2 LU
Not performed
t3 LU
Not performed
t 1.5 LU
t 1LU
t 1LU
Not performed t 1LU t 0.5 LU Normal Not performed
Dark Adaptation
6 9 15
24 6
11
84
40
72
28 37
33 16
Follow-up (mas)
RIOFB (E. magnet) PPV, RIOFB (Ocutome) PPV, RIOFB (I. magnet) PPV, PPL, RIOFB (forceps) (1) RIOFB (E. magnet), SBP (2) PPV, PPL, (12 mas after RIOFB) (1) RIOFB (E. magnet) (2) PPV, PPL, (16 mas after RIOFB) (1) PPV, RIOFB (E. magnet) (2) Lensectomy (23 mas after RIOFB) (3) SBP (24 mas after lensectomy) (4) PPV, AFX8 (1 mo after SBP) (1) PPV, PPL, RIOFB (forceps) (2) SBP (1 mo after RIOFB) PPV, PPL, SBP, AFX8, RIOFB (forceps) PPV, PPL, RIOFB (forceps) PPV, Phaco, PCIOL, RIOFB (E. magnet) PPV, ECCE, PCIOL Lensectomy (1) PPV, PPL, SBP, RIOFB (forceps) (2) SBP revision (2 mas after no. 1) (3) SBP revision (4 mas after no. 2)
Surgery
IOFB = intraocular foreign body; CE = cataract extraction; CF = count fingers; ERG = electroretinogram; RIOFB = remove intraocular foreign body; E. magnet = external magnet; LU = log units; PPV = pars plana vitrectomy, 1. magnet = intraocular magnet; OS = left eye; OD = right eye; PPL = pars plana lensectomy; HM = hand motions; SBP = scleral buckling procedure; AFX8 = air-ftuid exchange; Phaco = phacoemulsification; PCIOL = posterior chamber intraocular lens; ECCE = extracapsular cataract extraction.
4
Age (yrs)/Sex
Patient No.
Visual Acuity
Table 1. Management of Siderosis Bulbi
OPHTHALMOLOGY
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MARCH 1990
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VOLUME 97
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NUMBER 3
Fig I. Top left, iris heterochromia. Normal right eye. The left iris is darker than the right and there is a full-thickness hole in the iris at the 7o'clock position. Fig 2. Top right, slit lamp photograph of the left eye shows the corneal scar, the hole in the iris, and the brownish rust-colored anterior subcapsular lenticular deposits. Fig 3. Second row left, fundus photograph of the left eye demonstrates the swollen optic disc. The hazy view is due to the posterior subcapsular cataract. Fig 4. Second row right, fundus photograph of the inferior periphery of the left eye shows retinal pigment epithelial mottling and hypopigmentation adjacent to the more anteriorly located intraocular foreign body. Fig 5. Third row, late phase fluorescein angiogram of the left fundus demonstrates fluorescein leakage from the optic disc. Fig 6. Bottom left, histopathologic section of the anterior lens capsule of the left eye removed at the time of cataract extraction shows the intraepithelial brown iron granules and the basement membrane which stains purple (periodic acid-Schiff; original magnification, XIOO). Bottom right, histopathologic specimen of the anterior lens capsule demonstrates the presence of iron within the lens epithelium which stains blue (iron stain; original magnification, X I 00). (Figures used with permission from The University of Iowa: Pathology of the EyeAn Interactive Videodisc Program.)
the siderotic changes may stabilize or regress 5•6; the foreign body may lose its magnetic properties or become radiolucent to x-rays6 ; or progressive siderotic degeneration may occur. Patients with a clinical diagnosis of siderosis bulbi may present with iris heterochromia, pupillary mydriasis, chronic uveitis/iritis, or decreased vision secondary to cataract or less often due to retinal degenerative changes. To our knowledge, optic disc hyperemia has not been described previously in patients with siderosis bulbi. The etiology of this finding is unclear although other causes
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of optic disc edema (hypotony or vitreous inflammation) were not present. One might speculate that this represents a toxic effect on the optic nerve secondary to the iron, because the optic disc hyperemia disappeared after the IOFB was removed in 1 patient (patient 6). Long-term follow-up of the optic disc hyperemia in the other two patients (patients 10 and 11) using serial flicker fusion, visual acuity, and visual field testing is currently being pursued. An occult foreign body in the inferior anterior chamber angle is suggested by the presence of an inferior wedge-
SNEED AND WEINGEIST
shaped area of corneal edema. A full-thickness corneal scar, an iris defect, or the characteristic anterior subcapsular brownish lens opacities are clues that the eye contains an occult IOFB. The presence of an occult IOFB also should be entertained in eyes with unexplained unilateral iritis. The diagnosis of a retained IOFB is often made ophthalmoscopically or by slit-lamp examination. Gonioscopy will detect a foreign body in the anterior chamber angle. Slit-lamp examination after dilation may detect a lenticular foreign body. Results of dilated fundus examination can show a foreign body in the vitreous or on the retina if vitreous hemorrhage or a dense cataract is not present. The foreign body is often located inferiorly and if peripherally located is best visualized with scleral indentation. If the suspected IOFB is not seen clinically, further evaluation may be necessary. Plain film x-rays with the patient looking up and down may show a radio-opaque foreign body which changes position with eye movement. Computed tomographic scanning with thin cuts is often helpful in foreign body localization. Echography is a sensitive method in detecting the presence and location of an IOFB. A metallic foreign body localizer also can be used to determine the presence and location of an IOFB. Numerous management options are available once the diagnosis of siderosis bulbi secondary to a retained IOFB has been made. All patients should have a baseline ERG. Dark adaptation testing may be helpful. Foreign bodies encapsulated in the posterior segment are often difficult to remove, and siderotic changes may remain stable once encapsulation occurs. Serial evaluation with ERG testing every 2 to 3 months may be appropriate during the initial management of these eyes. If the ERG remains stable, the patient can continue to be observed with gradually increasing intervals between follow-up examinations. If deterioration of the ERG is demonstrated, the foreign body should be removed. Small foreign bodies located in the anterior segment also may be observed with serial ERGs. Removal of the IOFB should be strongly entertained in eyes with diminished ERGs and a mobile foreign body in the vitreous or a nonencapsulated foreign body on the retina. An external sclerotomy with removal using an external magnet may be successful in anteriorly located magnetic foreign bodies. The location of the sclerotomy can be marked externally on the sclera using scleral indentation, much like localizing a retinal tear in retinal reattachment surgery. Alternatively, a metallic foreign body localizer may be used when the foreign body cannot be visualized. A pars plana vitrectomy and removal with an intraocular magnet may be preferred for posteriorly located magnetic IOFBs. Iron-containing foreign bodies may lose their magnetic properties over time and a pars plana vitrectomy with removal using intraocular forceps may be necessary. A posteriorly located encapsulated IOFB is often best managed with a pars plana vitrectomy. Vitreous attachments to the capsule are severed and the capsule is then incised using a sharp instrument such as a myringotomy blade or a 20-guage needle. The foreign body is then removed with either an intraocular· magnet
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SIDEROSIS BULBI
or intraocular forceps. If the IOFB is fragile and fragments easily, removal using the suction mode of the vitrectomy probe or the aspiration needle may facilitate removal after the vitreous has been excised from the foreign body. The visual potential in eyes with siderosis bulbi may be excellent if the siderotic changes stabilize or improve, and if the optic nerve and macula have not been injured. Vision may be very good even in eyes with a half-normal ERG response. Visual acuity ranged from 20/15 to 20/ 40 in our patients over the follow-up period. Schocket et al 7 and Talamo et al 8 described separate cases of stabilized siderosis and visual acuity of 20/30 and 20/20, respectively, after removal of the foreign body and the siderotic cataract. A siderotic cataract may limit the patient's vision and/ or the ophthalmologist's view of the foreign body. These cataracts are not reversible even after the IOFB has been removed and cataract extraction may be required to improve visual acuity. We initially managed these cataracts with a pars plana lensectomy or with an anterior suction/ cutting approach. However, since the visual potential in these eyes is often excellent, we now prefer a combined extracapsular cataract extraction using nuclear expression or phacoemulsifi.cation with PC IOL implantation and simultaneous removal of the IOFB in older patients. Lens aspiration leaving an intact posterior capsule is appropriate in removing siderotic cataracts when they develop in younger patients. Siderosis bulbi is not commonly seen, but may develop in eyes with retained iron-containing IOFBs. The visual potential in eyes with siderosis bulbi is often excellent, and advances in vitreous surgery and cataract extraction have improved the visual rehabilitation in many of these eyes. Intraocular lens implantation has eliminated the need for aphakic contact lens correction in some eyes after cataract extraction. Although the foreign body is most often surgically removed, in some instances it may be left within the eye. In these cases, close follow-up with serial ERG evaluation is recommended.
REFERENCES 1. Duke-Elder S, ed. System of Ophthalmology. VoL XIV: Injuries. Pt. 1: Mechanical Injuries, St. Louis: CV Mosby, 1972; 525-44. 2. Davidson M. Siderosis bulbi. Am J Ophthalmol1933; 16:331-5. 3. Eisenberg 0. Beitrage zur Kenntisrder Siderosis bulbi [lnaug. Diss.]. Giessen, 1901. As cited in: Duke-Elder S, ed. System of Ophthalmology. VoL XIV: Injuries. Pt. 1: Mechanical Injuries. St. Louis: CV Mosby, 1972; 532. 4. Begle HL. Perforating injuries of the eye by small steel fragments. Am J Ophthalmol1929; 12:970-7. 5. Braendstrup P. Two cases of temporary siderosis bulbi with spontaneous resorption and without impairment of function. Acta Ophthalmol 1944; 22:311-6. 6. Casali A. Due casi di siderosi oculare. Ann di Ottal 1910; 39:572607. 7. Schocket SS, Lakhanpal V, Varma SO. Siderosis from a retained intraocular stone. Retina 1981; 1:201-7. 8. Talamo JH, Topping TM, Maumenee AE, Green WR. Ultrastructural studies of cornea, iris and lens in a case of siderosis bulbi. Ophthalmology 1985; 92:1675-80.
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