articles Posterior polar cataracts: A predisposition to intraoperative posterior capsular rupture Robert H. Osher, M.D., Bernard C.-Y. Yu, M.D., D ouglas D . Koch , M.D.
B TR T We p rform d phaco mul ification or planned extracap ula1' cataract e traction on po terior polar cataract in 31 eye of 22 pati nt and p ri n d ei ht ca e f p trior cap ular rupture (26~). ap ular ruptur occurred durin r mo al f th p t ri r p lar opacity or durin cleaning of the po trior cap ule aft r the opacity had been remo ed. W belie e thatexce i e adherenc ofthe opacity to the po terior cap ule and unu ual thinne f th cap ul pr di po d the e to p trior cap ular rupture.
K yWord:
ong nital catara t , p t ri r cap ular ruptur . po ·t riot' cataract, p trior polar catara t
Posterior polar cataract is one of the more common types of visually symptomatic congenital cataracts. This dense, white opacity is situated on the central posterior capsule and consists of a characteristic circular plaque with concentric whorls.),2 The opacity extends anteriorly into the posterior cortex and is thicker than the standard posterior subcapsular cataract. Over the past four years, we have operated on posterior polar cataracts in 31 eyes of 22 patients and have experienced eight cases of posterior capsular rupture (26%). In this report, we review Our exp erience with these patients, discuss possible etiologies, and suggest means for appropriately managing surgical complications associated with this type of cataract.
MATERIALS AND METHODS We conducted a retrospective review of our surgical records at the Cullen Eye Institute (DDK) and the
Cincinnati Eye Institute (RHO) from 1985 to the present and identified 22 consecutive patients (31 eyes) on whom we operated for congenital posterior polar cataracts. We established the diagnosis with preoperative slitlamp biomicroscopy (Figure 1). Mean patient age was 53 years with a range of 22 to 81 years. Family history was positive for congenital cataracts in 12 of 22 patients (55%); these patients indicated that the re was a history of inherited cataracts or that more than one family member had had cataracts diagnosed at a young age . Additional ocular or systemic disorders associated with the posterior polar cataracts could not be identified. Phacoemulsification was performed in 29 eyes and planned extracapsular cataract extraction in two . Posterior chamber intraocular lenses were implanted in the capsular bag in 25 eyes and in the ciliary sulcus in six eyes. Mean postoperative follow-up was 7.2 months
From the Cincinnati Eye Institute, Cincinnati, Ohio (Osher), and the Cullen Eye Institute, Houston, Texas (Yu and Koch). Reprint requests to Douglas D. Koch, M.D., Cullen Eye Institute, 6501 Fannin, NC-200, Houston, Texas 77030.
J CATARACT REFRACT SURG-VOL 16, MARCH 1990
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Fig. 1.
(Osher) Posterior polar cataracts showing dense, concentric, whorl-like opacities situated axially on the posterior capsule. Areas of peripheral cortical extension are also present in both eyes. Left: Right eye of Patient 2. Right: Right eye of Patient 3.
with a range of one week to 32 months. The patients' histories, ocular findings, surgical courses, and postoperative results are summarized in Table 1. We describe three patients whose courses typify the different responses of the posterior polar cataracts in this series. Patient 1 A 22-year-old white female presented to the Cullen Eye Institute on December 23, 1985, complaining of a bilateral progressive loss of vision. Her visual loss began when she was in third grade, and congenital cataracts were diagnosed one year later. Her brother and a paternal aunt also had congenital cataracts. Best corrected visual acuity was 20/30, J3 in the right eye and 20/25, J2 in the left eye. On slitlamp examination we observed dense circular plaques on the posterior capsules; these measured 3.4 mm and 3.6 mm in diameter, respectively. In addition, there were posterior cortical opacities radiating peripheral to the posterior polar opacities in both eyes, slightly worse in the right eye than in the left. A few anterior cortical vacuoles were also present bilaterally. Examination was otherwise unremarkable. Over the next three months, her symptoms increased and her visual acuity dropped to 20/40 in both eyes. On slitlamp examination, we noted that the peripheral cortical opacities had extended farther peripherally. We performed phacoemulsification and posterior chamber lens implantation in the capsular bag in the left eye on March 21, 1986, and in the right eye on June 18, 1986; there were no complications. In both eyes, the polar opacities were easily aspirated off the posterior capsule, which was vacuumed without difficulty. Postoperatively her acuity was 20/15 bilaterally. She subsequently developed capsular opacification in the left 1.58
eye and had a neodymium: YAG posterior caps ulotomy on July 19, 1988; acuity returned to 20/15 in this eye. Patient 2 A 46-year-old male presented to the Cincinnati Eye Institute on December 12, 1986, complaining of gradual, bilateral loss of vision for over five years; his major complaint was progressive light sensitivity and incapacitating glare. His family history was positive for congenital cataracts. Best corrected visual acuity was 20/50 in each eye, although he could not see the eye chart in bright illumination. Biomicroscopy revealed dense symmetrical axial posterior polar cataracts. The remainder of the examination was unremarkable. Surgery was performed on the left eye on January 8, 1987. Because the surgeon anticipated a possible torn posterior capsule, he modified the phacoemulsification technique by performing low power, low infusion, in situ emulsification. The opacity was removed as the phacoemulsification tip aspirated the posterior portion of the nucleus, leaving only the peripheral posterior cortex; this gave the appearance of a "pseudo-hole." The peripheral cortex was then aspirated, carefully avoiding the central capsule. After all cortex was removed, the peripheral posterior capsule was vacuumed. Finally, the irrigation/aspiration (I1A) tip on minimum setting was gently touched to the central posterior capsule, which instantly tore. The anterior chamber remained deep as the surgeon injected air through the second stab incision just prior to withdrawing the I1A tip. Injected sodium hyaluronate (Healon®) filled the capsular bag as air was removed in aliquots. A single-piece biconvex lens was implanted in the capsular bag without extending the tear, and the surgeon then removed Healon from a deep, closed chamber using a miniature I1A tip between sutures.
J CATARACT REFRACT SURG-VOL
16, MARCH 1990
Table 1. Patient characteristics. Intraoperative Rupture of Postt'rior Capsule OD* OSt
Agt' at Diagnosis of Cataract
Family History of Cataracts
2, ,56, M
? ?
+ +
Yes
3,22, F
9
+
No
4,26, F
'?
+
5, .31, M
20
6,41, F
10
Patit'nt, Agt', Sex
L 46, M
7,44, F
?
S, 49, M
39
9,50, M
? ?
10,61, F 11, 64, F
29
12,70, M
45
l.3, 76, M
14, SI, F
? ?
15,81, F
Childhood
16,34, M
31
17,44, F
40
IS, SI, M
75
No
Yt's
Postoperative Follow-up (months) OD OS II. 13
No
32
Yes No
No
+ +
20/20
20/20
Nd:YAG for secondary capsular opacification
1
20/20
Lens slightly decentered
20/40
20/20 20/60
10
No
No
12
1
20/20
20/20
No
1
6
20/20
20/20
No
No
Ph
12
20/20
20/20
No
1
No
20/20
2 Yes
5
20/25 I/J
20/20
2
No
+ + +
Iris fixation suture secured loose nasal haptic
20/20
29
9
20/2.5
Yes
IS
20/2.5
No
3
20/20
No
1 No
12
20/20
Ph
20/25
20/25
20/20
20/20
Ph
No
20/20 20/25
Yes
No
19,53, F
41
20,60, F
60
21,57, M
Childhood
No
12
20120
22, 5S, F
40
No
2
20/20
+
No
No
5
Postoperativt' Complications
20/20
No
Yes
+
2012,S
5 II.
Yes
+
9
Final Visual Acuity OD OS
Ph
20/20
*OD = right eye toS = It'ft eye
The patient attained a visual acuity of 20/20, and the intraocular lens appeared well centered throughout the one-year follow-up. Subsequent surgery in the fellow eye was without intraoperative or postoperative complications. Patient .3 A 56-year-old oriental male presented to the Cullen Eye Institute on May 19, 1987, complaining of a bilateral, gradual loss of vision over the previous 20 years; his family history was positive for congenital cataracts. Best corrected visual acuity was 20/60 in the right eye and 20/40 in the left. On slitlamp examination, bilateral posterior polar cataracts were present; these measured 3.,5 mm X 2.5 mm in the right eye and 3.0 mm X 2.5 mm in the left. In addition, there was moderate nuclear sclerosis in the right eye and mild nuclear sclerosis in the left. Phacoemulsification with posterior chamber lens implantation was performed in the right eye on
May 20, 1987. Following hydrodissection, the nucleus was emulsified in the posterior chamber; midway through the emulsification, it became evident that the posterior polar cataract was adherent to the posterior capsule. As the nucleus came forward, the opacity came with it, and the posterior capsule tore vertically into the zonules at 12 o'clock and 6 o'clock. Under Healon, a lens loop was used to extract the nucleus, then an anterior vitrectomy was performed through the rent. A McIntyre IIA system aspirated the remaining cortical material. A posterior chamber lens was inserted horizontally, ostensibly into the ciliary sulcus. The patient did well for the first two months postoperatively, but thereafter began to complain of intermittent diplopia. When the patient returned on February 26, 1988, the temporal lens haptic was well fixated in the capsular bag, but the nasal haptic was mobile. With changes in head position, the lens optic moved freely in and out of the visual axis. In March 1988, an iris-fixation suture was inserted to secure the
J CATARACT REFRACT SURG-vOL 16, MARCH 1990
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nasal haptic, and the patient's symptoms immediately resolved. The lens appeared stable and well centered, and the visual acuity remained correctable to 20/20.
RESULTS Intraoperative posterior capsular rupture occurred in eight of .31 eyes (26%). Seven capsular breaks occurred during phacoemulsification and one during planned extracapsular extraction. In four of these eight eyes, vitreous loss occurred, requiring automated anterior vitrectomy. In two eyes, intraocular lens decentration occurred, and in one of these, surgical repositioning was required. Postoperative visual acuity was 20/40 or better in all but one eye, which had preexisting amblyopia. Posterior capsular rupture took place during either posterior phacoemulsification, nucleus extraction, cortex removal, or vacuuming of the posterior capsule. In each instance, the break occurred as the posterior polar opacity was pulled or vacuumed off the posterior capsule. The posterior capsular break was round and centrally located, corresponding roughly to the region
of the posterior polar opacity, or it was a larger tear that included the central area. There were no significant differences between the capsular rupture group and the intact capsule group in age, sex, and family history.
DISCUSSION Posterior polar cataracts are dense, white opacities axially positioned on the posterior capsule.l,2 The central portion typically is circular and thick and has a characteristic concentric whorl-like appearance (Figure 1); it presumably arises before birth or in early infancy. Posterior polar cataracts can be stationary, consisting of only the well-circumscribed circular opacity, or they can be progressive. l Progression may begin in any decade and typically consists of whitish opacification that extends centrifugally along the posterior capsule. This extension is thinner and does not reach as far anteriorly as the original opacity; it has feathery or scalloped edges (Figure 2). Patients with progressive opacities can become more symptomatic as the peripheral extensions enlarge, as occurred with Patient 1.
Fig. 2.
160
J CATARACT REFRACT SURG- VOL
(Osher) Posterior polar cataracts with various amounts of peripheral cortical extension. AbOt,e Left: Irregular areas of extension with well-demarcated edges in left eve of Patient 22. Abol,e: Patchy, poorly circumscribed e~ten sion in left eye of Patient 6. Left: Diffuse posterior cortical opacification in left eye of Patient 2. Note feathery appearance.
16, MARCH 1990
Patients in this situation were often quite specific in identifying the onset of their symptoms and, as expected , most complained of increasing glare. However, patients with stationary opacities also complained of increasing symptoms that prompted their desire for cataract surgery. The reasons for this are not clear to us, but they may include increased density of th e opacity, age-related pupillary miosis, or increased functional needs or visual expectations. Posterior polar cataracts are usually inherited in an autosomal dominant mode;2-6 12 of our 22 patients (55%) had positive family histories consistent with this pattern. Sporadic cases may represent a new mutation. 7 Most reported pedigrees are associated with other ocular malformations or psychosomatic disorders;·5,7-11 however, none of our patients had any associated disease. The gene for posterior polar cataracts has been linked with the haptoglobin locus on chromosome 16. 12 There has been one report of a pedigree with autosomal recessive inheritance of posterior polar cataracts. 13 However, these patients also had retinitis pigmentosa, and the cataracts may have been posterior subcapsular cataracts associated with the retinitis pigmentosa. The pathogenesis of posterior polar cataracts is unknown. It has been suggested that they are caused by persistence of the hyaloid artery14-19 or invasion of the lens by mesoblastic tissue. 8,20 However, we did not observe hyaloid remnants in any of our patie nts, nor was there evidence of other juxtalenticular tissue except in one case in which we observed minute oildroplet particles just behind the posterior capsule. Posterior polar cataracts and posterior le nticonus 2L22 share several features. Both are posterior axial abnormalities that may be progressive and are predisposed to traumatic lens rupture. 23 However, differences between these two entities exist. 2,21 Posterior polar cataracts are predominantly inherited in an autosomal dominant fashion, whereas posterior lenticonus typically occurs sporadically. Posterior polar opacities are dense and compact, whereas the opacity of posterior lenticonus is usually porous. Posterior polar cataracts are bilateral, whereas posterior lenticonus is usually unilateral. There is no sexual predilection in posterior polar cataracts, whereas female preponderance is reported for posterior lenticonus. Finally, posterior lenticonus is characterized by a thin central posterior capsule that bulges posteriorly. No such posterior protuberance is present with posterior polar cataracts. The striking finding in our series was the 26% incidence of intraoperative rupture of the posterior capsule without apparent undue surgical trauma. This is in sharp contrast to the 1.1% incidence of posterior capsule tears reported in a large series of cataract operations perform ed by one of the authors (RHO).24
Moreover, the capsular opening in these instances was typically circular, corresponding to the rim of the opacity. This configuration differs from the irregular, highly variable configuration of standard surgically induced capsular ruptures. Hiles and Chotiner25 have previously noted that posterior polar cataracts are predisposed to vitreous loss, and Skalka23 reported one instance of traumatic posterior lens rupture with posterior polar cataract. We believe that there are two possible explanations for this phenomenon . First , there might be excessively tight adherence of the plaque to an otherwise normal posterior capsule. As traction is exerted on the plaq ue, it will not separate from the capsule, and the capsule eventually ruptures along the edge of the plaque. In effect, the capsule is torn away with the plaque. Second, it is possible that the posterior capsule underlying the cataract is unusually thin , and this inherent weakness could predispose to posterior capsular rupture with only minimal trauma. Traction on posterior lens fibers and the posterior polar opacity during routine cataract surgery may suffice to break this weakened capsule. Bernheimer26 reported on the histopathology of posterior polar cataract from a stillborn male , noting pronounced thinning of the posterior capsule in the region of the posterior polar cataract. Eshagian, 27 on the other hand, did not note such capsular thinning. However, in our Patient 2, the posterior capsule was unequivocally fragile. In addition, in some eyes with intact capsules, we observed that the central capsule underlying the opacity appeared to be slightly more translucent than the surrounding peripheral capsule. Indeed, we believe that both factors are involved and that their combined impact predisposes to capsular rupture. In some eyes, we were able to peel off the opacity and vacuum the posterior capsule without difficulty (e.g., Patien t 1). In another group of eyes, we could peel off the opacity, but the capsule ruptured with minimal trauma (e .g. , Patient 2). Finally, in ye t a third group, the opacity could not be removed without tearing the posterior capsule, and this sometimes occurred with minimal traction (e.g., Patient 3). In some eyes in this last group, capsular rupture might be prevented by leaving th e plaque in place at surgery. Neodymium:YAG posterior capsulotomy could be performed postoperatively, although the capsular opening would have to exceed the size of the plaque since it is unlikely that the laser could readily cut the plaque itself. However, in some cases the plaque is firmly adherent to the posterior aspect of the nucleus, and capsular rupture might be unavoidable. Most but not all the capsular ruptures occurred early in this series prior to our recognizing this association and modifying our surgical technique. We advocate preoperative oculopressure to soften the globe and
J CATARACT REFRACT SURG- VOL 16, MARCH 1990
161
diminish intraoperative posterior pressure. Gentle, in situ, low power, low infusion phacoemulsification may be preferable, since there is less stress on the posterior capsule than occurs with nuclear expression. Cortical aspiration is initially performed in the periphery, always stripping toward the central posterior capsule. As a rule, the central posterior capsule is quite clear since the opacity will lift off, leaving a clear "pseudohole" surrounded by cortex. If vacuuming or polishing the posterior capsule is undertaken, it should be performed first in the periphery. If there is a residual plaque following cortical removal, this should be left for later Nd:YAG capsulotomy. Alternatively, gentle vacuuming could be attempted using the IIA tip on the lowest possible aspiration setting. One of us (RHO) uses a technique termed "minimal residual aspiration" in which the foot pedal is depressed and released just as the IIA tip contacts the posterior capsule. The vacuum created by the elasticity of the tubing is enough to clean the capsule without risking a central tear. Should a capsular opening develop, chamber depth is maintained within a closed system with either air or a viscoelastic substance. Cortical removal is completed using low infusion to minimize the risk of vitreous herniation through the capsular defect. If the capsular opening remains small and central, lens implantation in the capsular bag can be safely performed. If marked extension of the rent occurs, the posterior chamber lens may be implanted in the ciliary sulcus. If capsulozonular integrity has been severely compromised, the surgeon might prefer to implant an anterior chamber lens, suture a posterior chamber lens, or avoid an intraocular lens in favor of an aphakic contact lens. Every patient who has a posterior polar cataract is advised of these alternatives during the preoperative counseling. Although the visual results in this series were excellent, our follow-up interval for many patients was too short to permit conclusions as to final visual outcome. Certainly, the patients who sustain capsular rupture, especially with vitreous loss, are at an increased risk for developing retinal complications. We believe these patients present a special challenge to the cataract surgeon. Careful preoperative and intraoperative planning are required to minimize the consequences of this predisposition to posterior capsular rupture and to increase the likelihood of a successful visual outcome. REFERENCES 1. Duke-Elder S: Posterior polar cataract. In: Duke-Elder S. ed, System of Ophthalmoloy, Vol III: Normal and Abnormal Development, Congenital Deformities. St Louis, CV Mosby, 1964, pp 723-726 2. Franc;:ois J: COllgenital Cataracts. Springfield, IL. Charles C Thomas, 1963, pp 111-118
162
J CATARACT REFRACT
3. Tulloh CG: Hereditary posterior polar cataract with report ofa pedigree. BrJ Ophthalmol 39:374-379, 1955 4. Nettleship E, Ogilvie FM: A peculiar form of hereditary congenital cataract. TrailS Ophthalmol Soc UK 26:191-207, 1906 5. Harman NB: New pedigrees of cataract-posterior polar. anterior polar and microphthalmia. and lamellar. Trans Ophtlwlmol Soc UK 29:296-306, 1909 6. Nettleship E: A pedigree of presenile or juvenile cataract. TrailS Ophthalmol Soc UK 32:337-352, 1912 7. Primrose DA: A slowly progressive degenerative condition characterized by mental deficiency, wasting of limb musculature and bone abnormalities, including ossification of the pinnae. ] Ment Defic Res 26:101-106, 1982 8. Greeves RA: Two cases of microphthalmia. TrailS Ophtlwlmol Soc UK 34:289-300, 1914 9. Ziegler SL, Griscom JM: Hereditary posterior polar cataract. with report of a pedigree. TrailS Am Ophtlwlmol Soc 14: 356-364, 1915 10. Franc;:ois J, Lambrechts J: Cataracte polaire posterieure congenitale et evolutive a heredite dominante. Bull Soc Beige Ophtalmol96:684-694, 1950 11. Bateman JB, Philippart M: Ocular features of the HagbergSantavuori syndrome. Am] Ophthalmol 102:262-271. 1986 12. Maumenee IH: Classification of hereditary cataracts in children by linkage analysis. Ophthalmology 86: 1554-1558, 1979 13. Saeb J: An investigation into the mode of heredity of congenital and juvenile cataracts. BrJ Ophthalmol33:601-629, 1949 14. Vogt A: Weitere Ergebnisse der Spaltlampenmikroskopie des vorderen Bulbusabschnittes. III. Abschnitt. Angeborene und friih erworbene Linsenveranderungen. Albrecht WIl Graefes Arch Ophthalmol 107:196-240, 1922 15. Vogt A: Weitere Ergebnisse der Spaltlampenmikroskopie des vorderen Bulbusabschnittes. III. Abschnitt(Fortsetzung). Angeborene und friih aufgetretene Linsenveranderungen. Albrecht von Graefes Arch Ophthalmol 108:182-191. 1922. 16. Volmer W: Angeborene Katarakt im Bereiche einer atypischen Ansatzstelle der Hyaloidea. Arch Altgenheilkd 97:31-35, 1926 17. Cordes FC: Types of congenital and juvenile cataracts. In: Haik GM, ed: Symposium 011 Diseases and Surgery 01 the Lens. St Louis, CV Mosby, 1957. pp 43-50 18. Gifford SR: Congenital anomalies of the lens as seen with the slit lamp. Am] Ophthalmol 7:678-68.5, 1924 19. Straub W: Seltenes Zusammentreffen verschiedener Missbildungen an einem Auge. Klin Monatsbl Allgenheilkd 114: 281, 1949 20. Szilv AV: The Dovne memorial lecture: The contribution of pathological exami'nations to the elucidation of the problems of cataract. Trans Ophthalmol Soc UK 58(II):595-660, 1938 21. Crouch ERJr, Parks MM: Management of posterior lenticonus complicated by unilateral cataract. Am ] Ophthalmol 85:503508, 1978 22. Khalil M, Saheb N: Posterior lenticonus. Ophthalmology 91: 1429-1430, 1984 23. Skalka HW: Ultrasonic diagnosis of posterior lens rupture. Ophthalmic Surg 8(6):72-76, 1977 24. Osher RH: The torn posterior capsule: Its intraoperative behavior, surgical management, and long-term consequences. In press, ] Cataract Refract Surg 25. Hiles DA, Chotiner B: Vitreous loss follOWing infantile cataract surgery. ] Pediatr Ophthalmol 14:193-199, 1977 26. Bernheimer S: Zur Kenntnis des angeborenen hinteren Polstares des Menschen. Arch Augellheilkd 74:8-12, 1913 27. Eshagian J: Human posterior subcapsular cataracts. TrailS Ophthalmol Soc UK 102:364-368, 1982
SURC- VOL 16, MARCH 1990
B TR T We p rform d phaco mul ification or planned extracap ula1' cataract e traction on po terior polar cataract in 31 eye of 22 pati nt and p ri n d ei ht ca e f p trior cap ular rupture (26~). ap ular ruptur occurred durin r mo al f th p t ri r p lar opacity or durin cleaning of the po trior cap ule aft r the opacity had been remo ed. W belie e thatexce i e adherenc ofthe opacity to the po terior cap ule and unu ual thinne f th cap ul pr di po d the e to p trior cap ular rupture.
K yWord:
ong nital catara t , p t ri r cap ular ruptur . po ·t riot' cataract, p trior polar catara t
Posterior polar cataract is one of the more common types of visually symptomatic congenital cataracts. This dense, white opacity is situated on the central posterior capsule and consists of a characteristic circular plaque with concentric whorls.),2 The opacity extends anteriorly into the posterior cortex and is thicker than the standard posterior subcapsular cataract. Over the past four years, we have operated on posterior polar cataracts in 31 eyes of 22 patients and have experienced eight cases of posterior capsular rupture (26%). In this report, we review Our exp erience with these patients, discuss possible etiologies, and suggest means for appropriately managing surgical complications associated with this type of cataract.
MATERIALS AND METHODS We conducted a retrospective review of our surgical records at the Cullen Eye Institute (DDK) and the
Cincinnati Eye Institute (RHO) from 1985 to the present and identified 22 consecutive patients (31 eyes) on whom we operated for congenital posterior polar cataracts. We established the diagnosis with preoperative slitlamp biomicroscopy (Figure 1). Mean patient age was 53 years with a range of 22 to 81 years. Family history was positive for congenital cataracts in 12 of 22 patients (55%); these patients indicated that the re was a history of inherited cataracts or that more than one family member had had cataracts diagnosed at a young age . Additional ocular or systemic disorders associated with the posterior polar cataracts could not be identified. Phacoemulsification was performed in 29 eyes and planned extracapsular cataract extraction in two . Posterior chamber intraocular lenses were implanted in the capsular bag in 25 eyes and in the ciliary sulcus in six eyes. Mean postoperative follow-up was 7.2 months
From the Cincinnati Eye Institute, Cincinnati, Ohio (Osher), and the Cullen Eye Institute, Houston, Texas (Yu and Koch). Reprint requests to Douglas D. Koch, M.D., Cullen Eye Institute, 6501 Fannin, NC-200, Houston, Texas 77030.
J CATARACT REFRACT SURG-VOL 16, MARCH 1990
157
Fig. 1.
(Osher) Posterior polar cataracts showing dense, concentric, whorl-like opacities situated axially on the posterior capsule. Areas of peripheral cortical extension are also present in both eyes. Left: Right eye of Patient 2. Right: Right eye of Patient 3.
with a range of one week to 32 months. The patients' histories, ocular findings, surgical courses, and postoperative results are summarized in Table 1. We describe three patients whose courses typify the different responses of the posterior polar cataracts in this series. Patient 1 A 22-year-old white female presented to the Cullen Eye Institute on December 23, 1985, complaining of a bilateral progressive loss of vision. Her visual loss began when she was in third grade, and congenital cataracts were diagnosed one year later. Her brother and a paternal aunt also had congenital cataracts. Best corrected visual acuity was 20/30, J3 in the right eye and 20/25, J2 in the left eye. On slitlamp examination we observed dense circular plaques on the posterior capsules; these measured 3.4 mm and 3.6 mm in diameter, respectively. In addition, there were posterior cortical opacities radiating peripheral to the posterior polar opacities in both eyes, slightly worse in the right eye than in the left. A few anterior cortical vacuoles were also present bilaterally. Examination was otherwise unremarkable. Over the next three months, her symptoms increased and her visual acuity dropped to 20/40 in both eyes. On slitlamp examination, we noted that the peripheral cortical opacities had extended farther peripherally. We performed phacoemulsification and posterior chamber lens implantation in the capsular bag in the left eye on March 21, 1986, and in the right eye on June 18, 1986; there were no complications. In both eyes, the polar opacities were easily aspirated off the posterior capsule, which was vacuumed without difficulty. Postoperatively her acuity was 20/15 bilaterally. She subsequently developed capsular opacification in the left 1.58
eye and had a neodymium: YAG posterior caps ulotomy on July 19, 1988; acuity returned to 20/15 in this eye. Patient 2 A 46-year-old male presented to the Cincinnati Eye Institute on December 12, 1986, complaining of gradual, bilateral loss of vision for over five years; his major complaint was progressive light sensitivity and incapacitating glare. His family history was positive for congenital cataracts. Best corrected visual acuity was 20/50 in each eye, although he could not see the eye chart in bright illumination. Biomicroscopy revealed dense symmetrical axial posterior polar cataracts. The remainder of the examination was unremarkable. Surgery was performed on the left eye on January 8, 1987. Because the surgeon anticipated a possible torn posterior capsule, he modified the phacoemulsification technique by performing low power, low infusion, in situ emulsification. The opacity was removed as the phacoemulsification tip aspirated the posterior portion of the nucleus, leaving only the peripheral posterior cortex; this gave the appearance of a "pseudo-hole." The peripheral cortex was then aspirated, carefully avoiding the central capsule. After all cortex was removed, the peripheral posterior capsule was vacuumed. Finally, the irrigation/aspiration (I1A) tip on minimum setting was gently touched to the central posterior capsule, which instantly tore. The anterior chamber remained deep as the surgeon injected air through the second stab incision just prior to withdrawing the I1A tip. Injected sodium hyaluronate (Healon®) filled the capsular bag as air was removed in aliquots. A single-piece biconvex lens was implanted in the capsular bag without extending the tear, and the surgeon then removed Healon from a deep, closed chamber using a miniature I1A tip between sutures.
J CATARACT REFRACT SURG-VOL
16, MARCH 1990
Table 1. Patient characteristics. Intraoperative Rupture of Postt'rior Capsule OD* OSt
Agt' at Diagnosis of Cataract
Family History of Cataracts
2, ,56, M
? ?
+ +
Yes
3,22, F
9
+
No
4,26, F
'?
+
5, .31, M
20
6,41, F
10
Patit'nt, Agt', Sex
L 46, M
7,44, F
?
S, 49, M
39
9,50, M
? ?
10,61, F 11, 64, F
29
12,70, M
45
l.3, 76, M
14, SI, F
? ?
15,81, F
Childhood
16,34, M
31
17,44, F
40
IS, SI, M
75
No
Yt's
Postoperative Follow-up (months) OD OS II. 13
No
32
Yes No
No
+ +
20/20
20/20
Nd:YAG for secondary capsular opacification
1
20/20
Lens slightly decentered
20/40
20/20 20/60
10
No
No
12
1
20/20
20/20
No
1
6
20/20
20/20
No
No
Ph
12
20/20
20/20
No
1
No
20/20
2 Yes
5
20/25 I/J
20/20
2
No
+ + +
Iris fixation suture secured loose nasal haptic
20/20
29
9
20/2.5
Yes
IS
20/2.5
No
3
20/20
No
1 No
12
20/20
Ph
20/25
20/25
20/20
20/20
Ph
No
20/20 20/25
Yes
No
19,53, F
41
20,60, F
60
21,57, M
Childhood
No
12
20120
22, 5S, F
40
No
2
20/20
+
No
No
5
Postoperativt' Complications
20/20
No
Yes
+
2012,S
5 II.
Yes
+
9
Final Visual Acuity OD OS
Ph
20/20
*OD = right eye toS = It'ft eye
The patient attained a visual acuity of 20/20, and the intraocular lens appeared well centered throughout the one-year follow-up. Subsequent surgery in the fellow eye was without intraoperative or postoperative complications. Patient .3 A 56-year-old oriental male presented to the Cullen Eye Institute on May 19, 1987, complaining of a bilateral, gradual loss of vision over the previous 20 years; his family history was positive for congenital cataracts. Best corrected visual acuity was 20/60 in the right eye and 20/40 in the left. On slitlamp examination, bilateral posterior polar cataracts were present; these measured 3.,5 mm X 2.5 mm in the right eye and 3.0 mm X 2.5 mm in the left. In addition, there was moderate nuclear sclerosis in the right eye and mild nuclear sclerosis in the left. Phacoemulsification with posterior chamber lens implantation was performed in the right eye on
May 20, 1987. Following hydrodissection, the nucleus was emulsified in the posterior chamber; midway through the emulsification, it became evident that the posterior polar cataract was adherent to the posterior capsule. As the nucleus came forward, the opacity came with it, and the posterior capsule tore vertically into the zonules at 12 o'clock and 6 o'clock. Under Healon, a lens loop was used to extract the nucleus, then an anterior vitrectomy was performed through the rent. A McIntyre IIA system aspirated the remaining cortical material. A posterior chamber lens was inserted horizontally, ostensibly into the ciliary sulcus. The patient did well for the first two months postoperatively, but thereafter began to complain of intermittent diplopia. When the patient returned on February 26, 1988, the temporal lens haptic was well fixated in the capsular bag, but the nasal haptic was mobile. With changes in head position, the lens optic moved freely in and out of the visual axis. In March 1988, an iris-fixation suture was inserted to secure the
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nasal haptic, and the patient's symptoms immediately resolved. The lens appeared stable and well centered, and the visual acuity remained correctable to 20/20.
RESULTS Intraoperative posterior capsular rupture occurred in eight of .31 eyes (26%). Seven capsular breaks occurred during phacoemulsification and one during planned extracapsular extraction. In four of these eight eyes, vitreous loss occurred, requiring automated anterior vitrectomy. In two eyes, intraocular lens decentration occurred, and in one of these, surgical repositioning was required. Postoperative visual acuity was 20/40 or better in all but one eye, which had preexisting amblyopia. Posterior capsular rupture took place during either posterior phacoemulsification, nucleus extraction, cortex removal, or vacuuming of the posterior capsule. In each instance, the break occurred as the posterior polar opacity was pulled or vacuumed off the posterior capsule. The posterior capsular break was round and centrally located, corresponding roughly to the region
of the posterior polar opacity, or it was a larger tear that included the central area. There were no significant differences between the capsular rupture group and the intact capsule group in age, sex, and family history.
DISCUSSION Posterior polar cataracts are dense, white opacities axially positioned on the posterior capsule.l,2 The central portion typically is circular and thick and has a characteristic concentric whorl-like appearance (Figure 1); it presumably arises before birth or in early infancy. Posterior polar cataracts can be stationary, consisting of only the well-circumscribed circular opacity, or they can be progressive. l Progression may begin in any decade and typically consists of whitish opacification that extends centrifugally along the posterior capsule. This extension is thinner and does not reach as far anteriorly as the original opacity; it has feathery or scalloped edges (Figure 2). Patients with progressive opacities can become more symptomatic as the peripheral extensions enlarge, as occurred with Patient 1.
Fig. 2.
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(Osher) Posterior polar cataracts with various amounts of peripheral cortical extension. AbOt,e Left: Irregular areas of extension with well-demarcated edges in left eve of Patient 22. Abol,e: Patchy, poorly circumscribed e~ten sion in left eye of Patient 6. Left: Diffuse posterior cortical opacification in left eye of Patient 2. Note feathery appearance.
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Patients in this situation were often quite specific in identifying the onset of their symptoms and, as expected , most complained of increasing glare. However, patients with stationary opacities also complained of increasing symptoms that prompted their desire for cataract surgery. The reasons for this are not clear to us, but they may include increased density of th e opacity, age-related pupillary miosis, or increased functional needs or visual expectations. Posterior polar cataracts are usually inherited in an autosomal dominant mode;2-6 12 of our 22 patients (55%) had positive family histories consistent with this pattern. Sporadic cases may represent a new mutation. 7 Most reported pedigrees are associated with other ocular malformations or psychosomatic disorders;·5,7-11 however, none of our patients had any associated disease. The gene for posterior polar cataracts has been linked with the haptoglobin locus on chromosome 16. 12 There has been one report of a pedigree with autosomal recessive inheritance of posterior polar cataracts. 13 However, these patients also had retinitis pigmentosa, and the cataracts may have been posterior subcapsular cataracts associated with the retinitis pigmentosa. The pathogenesis of posterior polar cataracts is unknown. It has been suggested that they are caused by persistence of the hyaloid artery14-19 or invasion of the lens by mesoblastic tissue. 8,20 However, we did not observe hyaloid remnants in any of our patie nts, nor was there evidence of other juxtalenticular tissue except in one case in which we observed minute oildroplet particles just behind the posterior capsule. Posterior polar cataracts and posterior le nticonus 2L22 share several features. Both are posterior axial abnormalities that may be progressive and are predisposed to traumatic lens rupture. 23 However, differences between these two entities exist. 2,21 Posterior polar cataracts are predominantly inherited in an autosomal dominant fashion, whereas posterior lenticonus typically occurs sporadically. Posterior polar opacities are dense and compact, whereas the opacity of posterior lenticonus is usually porous. Posterior polar cataracts are bilateral, whereas posterior lenticonus is usually unilateral. There is no sexual predilection in posterior polar cataracts, whereas female preponderance is reported for posterior lenticonus. Finally, posterior lenticonus is characterized by a thin central posterior capsule that bulges posteriorly. No such posterior protuberance is present with posterior polar cataracts. The striking finding in our series was the 26% incidence of intraoperative rupture of the posterior capsule without apparent undue surgical trauma. This is in sharp contrast to the 1.1% incidence of posterior capsule tears reported in a large series of cataract operations perform ed by one of the authors (RHO).24
Moreover, the capsular opening in these instances was typically circular, corresponding to the rim of the opacity. This configuration differs from the irregular, highly variable configuration of standard surgically induced capsular ruptures. Hiles and Chotiner25 have previously noted that posterior polar cataracts are predisposed to vitreous loss, and Skalka23 reported one instance of traumatic posterior lens rupture with posterior polar cataract. We believe that there are two possible explanations for this phenomenon . First , there might be excessively tight adherence of the plaque to an otherwise normal posterior capsule. As traction is exerted on the plaq ue, it will not separate from the capsule, and the capsule eventually ruptures along the edge of the plaque. In effect, the capsule is torn away with the plaque. Second, it is possible that the posterior capsule underlying the cataract is unusually thin , and this inherent weakness could predispose to posterior capsular rupture with only minimal trauma. Traction on posterior lens fibers and the posterior polar opacity during routine cataract surgery may suffice to break this weakened capsule. Bernheimer26 reported on the histopathology of posterior polar cataract from a stillborn male , noting pronounced thinning of the posterior capsule in the region of the posterior polar cataract. Eshagian, 27 on the other hand, did not note such capsular thinning. However, in our Patient 2, the posterior capsule was unequivocally fragile. In addition, in some eyes with intact capsules, we observed that the central capsule underlying the opacity appeared to be slightly more translucent than the surrounding peripheral capsule. Indeed, we believe that both factors are involved and that their combined impact predisposes to capsular rupture. In some eyes, we were able to peel off the opacity and vacuum the posterior capsule without difficulty (e.g., Patien t 1). In another group of eyes, we could peel off the opacity, but the capsule ruptured with minimal trauma (e .g. , Patient 2). Finally, in ye t a third group, the opacity could not be removed without tearing the posterior capsule, and this sometimes occurred with minimal traction (e.g., Patient 3). In some eyes in this last group, capsular rupture might be prevented by leaving th e plaque in place at surgery. Neodymium:YAG posterior capsulotomy could be performed postoperatively, although the capsular opening would have to exceed the size of the plaque since it is unlikely that the laser could readily cut the plaque itself. However, in some cases the plaque is firmly adherent to the posterior aspect of the nucleus, and capsular rupture might be unavoidable. Most but not all the capsular ruptures occurred early in this series prior to our recognizing this association and modifying our surgical technique. We advocate preoperative oculopressure to soften the globe and
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diminish intraoperative posterior pressure. Gentle, in situ, low power, low infusion phacoemulsification may be preferable, since there is less stress on the posterior capsule than occurs with nuclear expression. Cortical aspiration is initially performed in the periphery, always stripping toward the central posterior capsule. As a rule, the central posterior capsule is quite clear since the opacity will lift off, leaving a clear "pseudohole" surrounded by cortex. If vacuuming or polishing the posterior capsule is undertaken, it should be performed first in the periphery. If there is a residual plaque following cortical removal, this should be left for later Nd:YAG capsulotomy. Alternatively, gentle vacuuming could be attempted using the IIA tip on the lowest possible aspiration setting. One of us (RHO) uses a technique termed "minimal residual aspiration" in which the foot pedal is depressed and released just as the IIA tip contacts the posterior capsule. The vacuum created by the elasticity of the tubing is enough to clean the capsule without risking a central tear. Should a capsular opening develop, chamber depth is maintained within a closed system with either air or a viscoelastic substance. Cortical removal is completed using low infusion to minimize the risk of vitreous herniation through the capsular defect. If the capsular opening remains small and central, lens implantation in the capsular bag can be safely performed. If marked extension of the rent occurs, the posterior chamber lens may be implanted in the ciliary sulcus. If capsulozonular integrity has been severely compromised, the surgeon might prefer to implant an anterior chamber lens, suture a posterior chamber lens, or avoid an intraocular lens in favor of an aphakic contact lens. Every patient who has a posterior polar cataract is advised of these alternatives during the preoperative counseling. Although the visual results in this series were excellent, our follow-up interval for many patients was too short to permit conclusions as to final visual outcome. Certainly, the patients who sustain capsular rupture, especially with vitreous loss, are at an increased risk for developing retinal complications. We believe these patients present a special challenge to the cataract surgeon. Careful preoperative and intraoperative planning are required to minimize the consequences of this predisposition to posterior capsular rupture and to increase the likelihood of a successful visual outcome. REFERENCES 1. Duke-Elder S: Posterior polar cataract. In: Duke-Elder S. ed, System of Ophthalmoloy, Vol III: Normal and Abnormal Development, Congenital Deformities. St Louis, CV Mosby, 1964, pp 723-726 2. Franc;:ois J: COllgenital Cataracts. Springfield, IL. Charles C Thomas, 1963, pp 111-118
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3. Tulloh CG: Hereditary posterior polar cataract with report ofa pedigree. BrJ Ophthalmol 39:374-379, 1955 4. Nettleship E, Ogilvie FM: A peculiar form of hereditary congenital cataract. TrailS Ophthalmol Soc UK 26:191-207, 1906 5. Harman NB: New pedigrees of cataract-posterior polar. anterior polar and microphthalmia. and lamellar. Trans Ophtlwlmol Soc UK 29:296-306, 1909 6. Nettleship E: A pedigree of presenile or juvenile cataract. TrailS Ophthalmol Soc UK 32:337-352, 1912 7. Primrose DA: A slowly progressive degenerative condition characterized by mental deficiency, wasting of limb musculature and bone abnormalities, including ossification of the pinnae. ] Ment Defic Res 26:101-106, 1982 8. Greeves RA: Two cases of microphthalmia. TrailS Ophtlwlmol Soc UK 34:289-300, 1914 9. Ziegler SL, Griscom JM: Hereditary posterior polar cataract. with report of a pedigree. TrailS Am Ophtlwlmol Soc 14: 356-364, 1915 10. Franc;:ois J, Lambrechts J: Cataracte polaire posterieure congenitale et evolutive a heredite dominante. Bull Soc Beige Ophtalmol96:684-694, 1950 11. Bateman JB, Philippart M: Ocular features of the HagbergSantavuori syndrome. Am] Ophthalmol 102:262-271. 1986 12. Maumenee IH: Classification of hereditary cataracts in children by linkage analysis. Ophthalmology 86: 1554-1558, 1979 13. Saeb J: An investigation into the mode of heredity of congenital and juvenile cataracts. BrJ Ophthalmol33:601-629, 1949 14. Vogt A: Weitere Ergebnisse der Spaltlampenmikroskopie des vorderen Bulbusabschnittes. III. Abschnitt. Angeborene und friih erworbene Linsenveranderungen. Albrecht WIl Graefes Arch Ophthalmol 107:196-240, 1922 15. Vogt A: Weitere Ergebnisse der Spaltlampenmikroskopie des vorderen Bulbusabschnittes. III. Abschnitt(Fortsetzung). Angeborene und friih aufgetretene Linsenveranderungen. Albrecht von Graefes Arch Ophthalmol 108:182-191. 1922. 16. Volmer W: Angeborene Katarakt im Bereiche einer atypischen Ansatzstelle der Hyaloidea. Arch Altgenheilkd 97:31-35, 1926 17. Cordes FC: Types of congenital and juvenile cataracts. In: Haik GM, ed: Symposium 011 Diseases and Surgery 01 the Lens. St Louis, CV Mosby, 1957. pp 43-50 18. Gifford SR: Congenital anomalies of the lens as seen with the slit lamp. Am] Ophthalmol 7:678-68.5, 1924 19. Straub W: Seltenes Zusammentreffen verschiedener Missbildungen an einem Auge. Klin Monatsbl Allgenheilkd 114: 281, 1949 20. Szilv AV: The Dovne memorial lecture: The contribution of pathological exami'nations to the elucidation of the problems of cataract. Trans Ophthalmol Soc UK 58(II):595-660, 1938 21. Crouch ERJr, Parks MM: Management of posterior lenticonus complicated by unilateral cataract. Am ] Ophthalmol 85:503508, 1978 22. Khalil M, Saheb N: Posterior lenticonus. Ophthalmology 91: 1429-1430, 1984 23. Skalka HW: Ultrasonic diagnosis of posterior lens rupture. Ophthalmic Surg 8(6):72-76, 1977 24. Osher RH: The torn posterior capsule: Its intraoperative behavior, surgical management, and long-term consequences. In press, ] Cataract Refract Surg 25. Hiles DA, Chotiner B: Vitreous loss follOWing infantile cataract surgery. ] Pediatr Ophthalmol 14:193-199, 1977 26. Bernheimer S: Zur Kenntnis des angeborenen hinteren Polstares des Menschen. Arch Augellheilkd 74:8-12, 1913 27. Eshagian J: Human posterior subcapsular cataracts. TrailS Ophthalmol Soc UK 102:364-368, 1982
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