Comparison of intracapsular and Extracapsular Cataract Surgery

Comparison of Intracapsular and Extracapsular Cataract Surgery Histopathologic Study of Eyes Obtained Postmortem PETER J. McDONNELL, MD, ARUN PATEL, MD, W. RICHARD GREEN, MD

Abstract: We examined 201 consecutive aphakic and pseudophakic eyes postmortem. Of these, 146 eyes had undergone intracapsular cataract extraction (lCCE) and 55 eyes had undergone extracapsular cataract extraction (ECCE), either with the posterior capsule preserved intact (ECCE-CI, 30 eyes) or having had a surgical discission performed (ECCE-D, 25 eyes). Wound-related complications were most numerous in the ICCE group, and this probably reflects the relatively recent development of microsurgical techniques. Posterior vitreous detachment was present in 84% of eyes following ICCE, in 76% of eyes following ECCE-D, and in 40% of eyes following ECCE-CI (P < 0.001). Peripheral retinal holes were found in 8.2% of ICCE eyes, 8.0% after ECCE-D, and 3.3% of eyes after ECCE-CI. Five (3.4%) of ICCE eyes had associated retinal detachments, while no ECCE eyes had detachments. Macular edema, macular holes, and epiretinal membranes occurred in 2.1%,1.4%, and 12.3% of ICCE eyes; 4.0%, 0.0%, and 8.0% of ECCE-D eyes; and 0.0%,6.7%, and 6.7% of ECCE-CI eyes, respectively. [Key words: aphakia, cystoid macular edema, extracapsular cataract extraction, intracapsular cataract extraction, posterior vitreous detachment, pseudophakia, retinal breaks, retinal detachment.] Ophthalmology 92: 1208-1225, 1985

The extracapsular method of cataract extraction is gaining increasing favor over intracapsular surgery. In addition to preserving an intact capsule separating the posterior chamber from the vitreous cavity, the extracapFrom the Eye Pathology Laboratory, Wilmer Ophthalmological Institute and Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, Maryland. Presented at the Eighty-ninth Annual Meeting of the American Academy of Ophthalmology, Atlanta, Georgia, November 11-15, 1984. Reprint requests to W. Richard Green, MD, Eye Pathology Laboratory, Johns Hopkins Hospital, 600 N. Wole Street, Baltimore, MD 21205.

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sular technique allows insertion of a posterior chamber intraocular lens_ By leaving a barrier to anterior displacement of the vitreous body, extracapsular surgery might be expected to have a lower frequency of vitreoretinal complications such as retinal pits, breaks and retinal detachment- The ideal study, a large series of patients randomized to intracapsular or extracapsular surgery and followed long-term with comparison of complication rates, does not exist- Several clinical studies, however, have provided evidence that cystoid macular edema! ,2 and retinal detachment!,3 may occur with a lower frequency following extracapsular when compared to intracapsular surgery. Experimental studies suggest that an intact pos-

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terior capsule decreases the likelihood of extension of infection from the anterior chamber to the vitreous cavity.4 This report describes the pathologic findings in a large consecutive series of aphakic and pseudophakic eyes examined postmortem with the goal of providing additional information regarding possible differences between the two types of cataract surgery.

MATERIALS AND METHODS A total of 20 1 consecutive aphakic and pseudophakic eyes obtained between 1979 and 1983 were included in this study. Eyes were classified according to the type of operation performed: intracapsular (ICCE), extracapsular with surgical discission (ECCE-D), or extracapsular surgery with preservation of the intact posterior capsule (ECCE-CI). The patients in the three different groups did not differ significantly in age (ICCE, mean age 75.5 ± 10.3; ECCE-D, 72.2 ± 20; and ECCE-CI, 75.4 ± 9.4 years). The interval between surgery and death was unknown in most cases. The eyes were fixed in 4% buffered formaldehyde for 48 hours or longer, washed in tap water overnight, and transferred to 60% alcohol. The eyes were opened vertically with removal of the temporal callotte. Gross examination was performed with a dissecting microscope and a movable fiberoptic source of illumination. The gross examination of all eyes was conducted by or supervised by one of the authors (WRG). The globe was suspended from the optic nerve and the status of the vitreous assessed. The nasal callotte was then removed. Stepped sections in the plane of the cataract wound, center of the pupil and optic nerve head were stained with hematoxylin and eosin, periodic acid-Schiff, and other stains as appropriate. Pseudophakic eyes were processed with the lenses in situ. Sections were obtained through the temporal callotte to include the macula. In addition, if any focal lesions were noted on gross examination, appropriate specimens were Fig I. Complications involving cataract wounds. Top, malapposition (arrow) of single plane cataract incision (E.P. 51645, hematoxylin-eosin, X45). Bottom, iris passes through break in Descemet's membrane and is incarcerated in posterior half of cataract wound (E.P. 51562, periodic acid-Schiff, X 115).

Table 1. Complications of Limbal Wound Operation Performed Wound Feature

ICCE

ECCE-D

Total 146 25 7 (4.8%) Malapposition of wound edges 18 (12%) 5 (20%) Iris incarceration 10 (6.8%) 1 (4.0%) Vitreous incarceration 3 (2.1%) 3 (12%) Stripping of Descemet's membrane 2 (1.4%) 2 (8.0%) Fibrous tissue ingrowth Epithelial ingrowth o o 1 (0.7%) o Posterior incision with cyclodialysis

o

ECCE-CI

30

o o o o o o o

ICCE = intracapsular cataract extraction; ECCE-D = extracapsular cataract extraction with surgical discission; ECCE-CI = extracapsular cataract extraction with posterior capsule preserved intact.

submitted for microscopic correlation. On gross and histologic examination, retinovitreal attachments were noted and eyes were categorized as having: (1) no posterior vitreous detachment when a layer of vitreous was attached to the entire retina and optic disc; (2) partial posterior vitreous detachment when a portion of the vitreous was detached from the optic disc or the retina posterior to the equator of the eye; or (3) complete posterior vitreous detachment when the vitreous was detached from the optic disc and the vitreoretinal separation extended to or anterior to the equator of the eye.

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Fig 2. Vitreous incarceration in cataract wound with endothelialization and descemetization (E.P. 56790). Top lefl . gross appearance of vitreous with adherence to pupillary margin of iris (arrow) and extension into anterior chamber (arrowhead) to limbal incision. Top right. area shows vitreous (asterisk) adherent to surgical scar, and pupillary margin of superior iris leaflet and extension posteriorly (arrow) (periodic acid-Schiff, X30). Bottom lefl. higher power of vitreous (asterisk) adherent to posterior aspect of cataract wound. Vitreous strand is covered by an attenuated layer of endothelium and a basement membrane (arrows) (endothelialization and descemetization) (periodic acid-Schiff, X I90). Bottom right. iridovitreal synechiae, with entropion uvea and minimal extension of iris pigment epithelium onto vitreous posteriorly (arrow) (periodic acid-Schiff, X 190).

Among the 146 eyes of the ICCE group, 69 (47%) were female, 77 (52%) were male. Nine (6%) were black, 137 (94%) were white. Among the 25 ECCE-D cases, 15 (60%) were female, 10 (40%) were male, and aU patients were white. Of the 30 ECCE-CI cases, 15 (50%) were female, 15 (50%) were male, and 28 (93%) were white and 2 (7%) were black. Two eyes had diabetic retinopathy and one eye had a branch retinal vein occlusion.

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RESULTS COMPLICAnONS RELATED TO WOUND HEALING

The complications noted at the limbal surgical wounds are presented in Table I . In general, faulty wound closure

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Fig 3. Vitreous incarceration in cataract wound. Top left. vitreous strand (arrowheads) extends from margin of pupil to cataract wound (E.P. 50794). Top righi, pigmented vitreous strand (arrowheads) incarcerated in limbal wound (E.P. 54098, left eye). Middle left, gross appearance of posterior vitreous detachment (arrows) following intracapsular cataract extraction (E.P. 54527). Middle right, closer view of same eye reveals vitreous extension through peripheral iridectomy (asterisk) in limbal wound. Bottom left, vitreous adherent to pupillary margin of iris (arrowhead) and extension to surgical wound (arrow) (E.P. 51445, periodic acid-Schiff, X30). Bottom center, higher power of same eye shows incarcerated vitreous with extension of corneal endothelial cells (arrowheads) onto vitreous (periodic acidSchiff, X260). Bottom right, different areas of same eye show prolapse of vitreous into the anterior chamber past the inferior iris leaflet (hematoxylin-eosin, X 110).

was responsible for the lesions seen, including malapposition of the wound edges alone (Fig 1, top) or with incarceration of the vitreous (Figs 2-4) or iris (Figs 1 bottom, 4, 5). Stripping of Descemet's membrane (Fig 6) seen in six eyes, was minimal in degree. Vitreous incarceration was typically accompanied by migration of endothelial cells onto the vitreous strand with production of basement membrane. Fibrous downgrowth, seen in four eyes, was minimal in three eyes and massive in one eye (Fig 5). There were no eyes with epithelial downgrowth. A posteriorly placed limbal incision had produced a cyclodialysis in one eye (Fig 7) and in one eye superior iridodialysis occurred at the time ofICCE (Fig 8). Complications were most numerous in eyes following ICCE, and no wound complications were seen in ECCE-CI eyes.

ANTERIOR SEGMENT FINDINGS

Features ofthe anterior segment other than the surgical wound are noted in Table 2. Intraocular lenses were present in some eyes of all three groups. Iris plane lenses predominated in ICCE eyes, while posterior chamber lenses were the most common in ECCE-CI eyes. Peripheral anterior synechiae were present in about 10% of all eyes, and were extensive in two ICCE eyes which showed extensive glaucomatous damage (Fig 9). Pigment dispersion, with extensive pigment deposition within the trabecular meshwork, within clump cells of the iris, and within corneal endothelial cells (Fig 10) was seen in about 6% of eyes overall. Iridovitreal synechiae were common following ICCE (Figs 3, 11, 12) and ECCE-D (Fig 13).

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Fig 4. Iris and vitreous to cataract wound. Top left . area shows vitreous strand (arrowhead) and iris incarceration in cataract wound (asterisk) (E.P. 55670, periodic acid-Schiff, X30). Top right. higher power of same eye demonstrates deposition ofa periodic acid-Schiff-positive basement membrane (arrowhead) on anterior surface of vitreous strand (periodic acid-Schiff, X 180). BOllom left. higher power of vitreous strand reveals endothelial cells (arrowheads) and a basement membrane (arrow) that have grown onto surface of vitreous. Additional vitreous strands (asterisk) are adherent to pupillary margin of iris (periodic acid-Schiff, X425). Bottom right. vitreous strand (arrowhead) with endothelium on its anterior surface is adherent to anterior surface of inferior iris leaflet at pupillary margin. Vitreous (arrow) is also adherent to the remainder of pupillary margin. Corneal endothelium is markedly attenuated (hematoxylin-eosin, X 185).

In general, the discissions that had been performed were large and constituted a defect of between 25 to 40% of the surface area of the posterior capsule (Figs 13-15). VITREORETINAL FINDINGS

Features of the posterior segment are noted in Table 3. Posterior vitreous detachment (PVD) was a common finding (Figs 3, 16) and was seen in most eyes with ICCE and ECCE-D, but in the minority of eyes with ECCE-CI. There was no statistically significant difference between

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the frequency of PVD for ICCE and ECCE-D. Among ECCE-CI eyes, however, the frequency of PVD was significantly less than for ICCE (P < 0.0001) and for ECCED (P < 0.01). Partial detachments comprised an increasingly large percentage of all PVDs in a progression from ICCE to ECCE-D to ECCE-CI. There was a general tendency for the percentage of eyes with PVD to increase with increasing age (Table 4). The rates of PVD were slightly higher in females than males (Table 5). The anterior vitreous was examined for the presence of pigmented macrophages (Fig 10). These were seen in

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Fig 5. Iris and vitreous incarceration in cataract wound with fibrous tissue ingrowth and traction retinal detachment (E.P. 56220). Top, gross appearance showing cataract wound (arrowhead), fibrous ingrowth (asterisks), and retinal detachment following intracapsular cataract extraction. Bottom, region of cataract wound (arrowhead) with iris and vitreous incarceration and marked fibrous tissue ingrowth (asterisk). Vitreous (arrow) is continuous with fibrous tissue (periodic acid-Schiff, X30).

Fig 6. Examples of stripping of Descemet's membrane with cataract surgery. Top left, healed scar of cataract incision (arrow) with 1.5 mm area of stripped Descemet's membrane (between arrowheads) (E.P. 39667, periodic acid-Schiff, X45). Top right, higher power of same eye shows anterior margin of area of stripped Descemet's membrane (arrowhead). Endothelial cells have extended onto stripped area and created a new, but thin periodic acid-Schiff-positive basement membrane (periodic acid-Schiff, X450). Bottom left, stripped and detached Descemet's membrane is adherent to anterior surface of iris, Endothelial cells (arrowheads) cover both surfaces of Descemet's membrane (arrowheads) (E.P. 47467, hematoxylin-eosin, X45). Bottom right, higher power of Fig C shows endothelial cells (arrowheads) on both aspects of stripped, folded, and thickened Descemet's membrane (hematoxylin-eosin, X375).

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Fig 8. External (top left), transillumination (top right), and internal gross (bottom) appearance of iridodialysis (asterisk) complicating intracapsular

cataract extraction (E.P. 56017).

Fig 7. Top, cyclodialysis (asterisk) associated with cataract incision (arrowhead) that is located posterior to scleral spur (arrow) (E.P. 51175. hematoxylin-eosin, X30). Bottom, higher power shows scleral spur (arrow) and anterior portion of longitudinal ciliary muscle fibers (arrowhead) as transected by posteriorly located cataract incision (asterisk) (hematoxylineosin, X 130).

most eyes following ICCE (92%) and following ECCE-D (64%), but in only 13% of eyes after ECCE-C!. The differences among the three groups were statistically significant. Peripheral retinal holes (Figs 17, 18) occurred with an overall frequency of7.5%, and the frequency did not vary significantly among the three groups. Retinal pits (Figs 16, 17) and retinal detachments were both found only in eyes following ICCE. Vitreoretinal traction without hole formation (Fig 19) was seen in two eyes. Macular lesions included edema (Fig 20, top), hole formation (full-thickness, 2) (Fig 20, bottom), and lamellar (2) (Fig 21), and preretinal membrane formation (Figs 21, 22). The frequency of these lesions did not differ significantly among the three groups of operated eyes. Of the

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two ICCE eyes with macular holes, both had PVD and one had a horseshoe tear in the retinal periphery. Both of these patients were female. Of the two ECCE-CI eyes with holes, one had PVD and the other did not. One patient was male, the other female. No patients had a known history of trauma (other than surgical) or diabetes, and none had pathologic evidence of diabetic retinopathy or other traumatic lesions such as angle recession. Table 2. Anterior Segment Findings Operation Performed Feature of Anterior Segment

ICCE

ECCE-D

ECCE-CI

Total Intraocular lens Anterior chamber Iris plane Posterior chamber Peripheral anterior synechiae Pigment dispersion Iridovitreal synechiae Iridocapsular synechiae

146 11 (7.5%)

25 12 (48%)

30 16 (53%) 1

2 9

o

16 (11%) 7 (4.8%) 36 (25%)

o

3

3

6

3 (12%) 4 (16%) 3 (12%) 5 (20%)

1

14 3 (10%) 1 (3.3%)

o

1 (3.3%)

ICCE = intracapsular cataract extraction: ECCE-D = extracapsular cataract extraction with surgical discission; ECCE-CI = extracapsular cataract extraction with posterior capsules preserved intact.

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Fig 9. Secondary closed-angle glaucoma after intracapsular cataract extraction. Top. area shows closure of anterior chamber angle by peripheral anterior synechia (E.P. 57165, hematoxylin-eosin, X 125). Middle. gross appearance of massive glaucomatous cupping of optic nerve head. Bottom, section through optic nerve head shows loss of all prelaminar tissue and marked outward bowing of the lamina cribrosa (periodic acid-Schiff, X30).

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Fig 10. Pigment dispersion following intracapsular cataract extraction. Top. numerous pigment-laden macrophages present in the angle. Some pigmented macrophages and free pigment along with pigment within endothelium are present in the trabecular meshwork (E.P. 56547, hematoxylin-eosin, X 130). Middle. extensive melanin pigment is present within endothelial cells of trabecular meshwork and within Schlemm's c.anal (E.P. 55337, hematoxylin-eosin, X350). Bottom. pigmented macrophages in anterior vitreous (arrowheads) (E.P. 51445, hematoxylineosin, X 135).

DISCUSSION LIMBAL WOUND

Complications related to the surgical wound, in general, were minor. Complications were most numerous in ICCE eyes, and no complications were seen in the 30 ECCE-CI eyes. The most reasonable interpretation of these data is that they reflect improved wound closure as better suture material and improved microsurgical techniques have been utilized coincident with increasing use of extracap-

sular surgical techniques. It is unlikely, in our opinion, that preservation of the posterior capsule accounts for fewer limbal wound complications. It is possible, however, that if the anterior vitreous is engaged at the time of posterior capsulotomy, the vitreous could follow the instrument to the wound, resulting in vitreous incarceration. This might explain the one instance of vitreous incarceration among the ECCE-D eyes. It was of interest to note the growth of endothelial cells

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Fig 11. E.P. 56803. lridovitreal synechia and prolapse of vitreous into anterior chamber after intracapsular cataract extraction. Top leji, gross appearance of iridovitreal synechia (arrowheads). Top right, higher power view shows iridovitreal synechia (arrowhead) and vitreous along anterior surface of inferior iris leaflet (arrow). Middle leji, inferior iris leaflet with vitreous adherent at pupillary margin (arrowhead) and at points along anterior surface of iris (arrow) (hematoxylineosin, X30). Middle right, higher power shows vitreous with free pigment and a few round cells adherent to anterior surface of iris (hematoxylin-eosin, X 180). Bottom leji, superior iris leaflet has an entropion configuration with vitreous adherent at pupillary margin (arrowhead) and along the posterior surface of the iris where iris pigment epithelium is absent (arrow). Vitreous extends into anterior chamber and along anterior surface of iris (asterisk) (hematoxylin-eosin, X 100).

onto the vitreous in the setting of vitreous incarceration.

It seems likely that this mechanism may contribute to

reduction in the number of endothelial cells and subsequent corneal decompensation. ANTERIOR SEGMENT

Peripheral anterior synechiae occurred with about equal frequency following the three types of surgery. In only

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two instances were these accompanied by glaucoma. Iridovitreal synechiae were common in ICCE eyes and ECCE-D eyes. The synechiae were often associated with mild localized chronic inflammation of the iris. The surgical discissions were typically large and thus the vitreolenticular relationships in these eyes probably simulated more closely the ICCE situation than the situation of an intact posterior capsule.

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Fig 12. lridovitreal synechia after intracapsular cataract extraction. Top, synechiae between pupillary margin of iris and vitreous (arrowhead) (E.P. 56017, periodic acid-Schiff, X225). Middle, iridovitreal synechia (arrowhead) at anterior margin of iridectomy (hematoxylin-eosin, X I(0). Botlorn, iridovitreal synechia (arrowhead) at posterior margin of iridectomy (hematoxylin-eosin, X I00).

VITREORETINAL FINDINGS AFTER CATARACT SURGERY

The validity of determining the presence or absence of posterior vitreous detachment in autopsy eyes by gross and/or histopathologic examination may be questioned. Postmortem enucleation, fixation, and sectioning and manipulation during gross examination may be sufficient to disrupt weak vitreoretinal attachments, leading to the over diagnosis of vitreous detachment. The frequency of clinically diagnosed posterior vitreous detachment in aphakic eyes has been reported to range from 66%5 to 100%.6.7 Foos and co-workers8,9 have shown from the examination of autopsy eyes that: (1) posterior vitreous detachment is over diagnosed clinically (probably at least in part as a result of erroneous diagnosis in eyes with large central syneresis; and (2) aphakia is clearly associated with an increased incidence of posterior vitreous detachment. In interpreting the results of our study, we made the assumption that whatever artifacts are introduced in the postmortem diagnosis of posterior vitreous detachment, they are produced about equally in eyes having undergone each of the three types of cataract surgery. . We found that posterior vitreous detachment was pres-

Fig 13. Extracapsular cataract extraction with capsulotomy. Top. margins of posterior capsulotomy (arrowheads). Residual cortical material is more abundant superiorly (asterisk). The anterior hyaloid membrane is discontinuous in the area of capsulotomy (E.P. 49334, hematoxylin-eosin, X20). Middle, vitreous strand (arrowhead) is adherent to superior margin of capsulotomy (arrow) and to pupillary margin of superior iris leaflet (periodic acid-Schiff, X45). BOllom, pupillary margin of inferior iris leaflet is adherent to inferior margin of capsulotomy (arrowheads). Only anterior capsule (arrow) and hyperplastic lens epithelium (asterisk) are present (periodic acid-Schiff, X 125).

ent in 76% of aphakic and pseudophakic eyes overall, but with a statistically significant lower frequepcy (40%) in eyes with an intact posterior capsule (P < 0.0001 compared to ICCE eyes). The frequency of posterior vitreous detachment in eyes following extracapsular surgery with large surgical discissions did not differ from the frequency after intracapsular surgery. Foos, 8 in his large series, included 62 surgically aphakic eyes. Eight had extracapsular surgery (status of posterior capsule not specified), and the remainder had intracap-

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Fig 14. Extracapsular cataract extraction with capsulotomy. Top, wide surgical posterior capsulotomy (between arrowheads). There is slight overlap of the cataract wound (asterisk) and iris pigment epithelium is absent from much of the superior iris leaflet (arrow) (E.P. 57410, hematoxylin-eosin, X 12). Middle, superior margin of capsulotomy (arrow) and intact anterior vitreous face posterior to plane of capsule (arrowhead) (hematoxylin-eosin, X60). Bot/om. area showing inferior margin of capsulotomy (arrowheads), hyperplastic lens epithelial cells (asterisk) and anterior hyaloid (arrow) (hematoxylin-eosin, X50).

sular surgery. He reported there was no difference in the frequency of posterior vitreous detachment between the two groups (ie. ICCE vs. ECCE). It may be that a large series, such as the present study, was required to demonstrate the difference in rates of posterior vitreous detachment between ICCE and ECCE-CI eyes. In addition, our study suggests that a large posterior capsulotomy allows posterior vitreous detachment to occur with the same frequency as in ICCE eyes. FOOS8 did not examine thi~ variable. We interpreted these data as being consistent with the thesis that preservation of an intact posterior capsule somehow stabilizes the vitreous and delays the onset of posterior vitreous detachment. A large posterior capsulotomy appears to negate this advantage, but this

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Fig 15. Extracapsular cataract extraction with secondary capsulotomy. Top. margins of posterior capsulotomy (arrowheads). Hyaloid membrane is discontinuous in area of capsulotomy (E.P. 48438, periodic acid-Schiff, X 12). Middle. superior margin of capsulotomy with multilayered membranous hyperplastic lens epithelium (arrowhead). A fragment of anterior lens capsule (arrow) is entrapped in the hyperplastic lens epithelium (periodic acid-Schiff, X 110). Bottom. higher power of inferior margin of capsulotomy shows a thin, aceliular membrane (arrow) on the anterior surface of the posterior capsule. Apparent contraction of this membrane has produced wrinkling of the posterior capsule (arrowheads). More peripherally, there is a thick membrane of hyperplastic lens epithelium (asterisk) (periodic acid-Schiff, X 110).

finding does not necessarily apply to small discissions or those made postoperatively with the Y AG laser. There are two possible explanations for the lower frequency of posterior vitreous detachment in eyes with intact posterior capsules. One theory emphasizes the mechanical changes induceQ by aphakia. Removal of the intact lens allows forward movement dfthe vitreous body which in turn results in detachment of the posterior vitreous. Preservation of the intact capsule would restrict, but not eliminate this forward displacement. It is possible that creation of a small anterior capsulotomy would not sacrifice the mechanical advantage of the anterior hyaloid face were it to remain intact. A second theory proposes that hyaluronic acid, a chief constituent of the vitreous, is instrumental i'n maintaining the volume of the vitreous, and may diffuse into the anterior chamber following lens extraction. Osterlin 10 demonstrated consistently lower concentrations of hyaluronic acid in aphakic eyes when compared to the fellow, phakic

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Table 3. Vitreoretinal Findings

Table 4. Frequency of Posterior Vitreous Detachment (PVD) According to Age

Operation Performed Vitreoretinal Feature

ICCE

ECCE-D

ECCE-CI

Total Posterior vitreous detachment Partial Complete Pigment anterior vitreous Peripheral retinal hole Retinal detachment Retinal pits Traction on retina without hole Macular edema Macular hole Preretinal membrane

146 122 (84%) 8 114 134 (92%) 12 (8.2%) 5 (3.4%) 3 (2.1%) 0 3 (3.1%) 2 (1.4%) 18 (12.3%)

25 19 (76%) 4 15 16 (64%)t 2 (8.0%) 0 0 1 (4.0%) 1 (4.0%) 0 2 (8.0%)

30 12 (40%)*t 5 7 4 (13%)*t 1 (3.3%) 0 0 1 (3.3%) 0 2 (0.7%) 2 (6.7%)

ICCE = intracapsular cataract extraction: ECCE-D = extracapsular cataract extraction with surgical discission; ECCE-CI = extracapsular cataract extraction with posterior capsules preserved intact. * P< 0.0001 compared to ICCE. tP< 0.01 compared to ECCE-D. tP < 0.01 compared to ICCE.

Operation Performed ICCE Age (Years)

Total

PVD:No. (%)

",;59 60-69 70-79 80-89 290

7 27 50 48 8

5 (71%) 20 (74%) 42 (84%) 42 (87%) 7 (88%)

ECCE-D Total 4

7

10 4 0

ECCE-CI

PVD:No. (%)

Total

PVD:No. (%)

2 (50%) 5 (71%) 8 (80%) 4 (100%) 0

1 7 10 9 2

1 (100%) 3 (430/0) 1 (10%) 6 (67%) 1 (50%)

ICCE = intracapsular cataract extraction: ECCE-D = extracapsular cataract extraction with surgical disCission; ECCE-CI = extracapsular cataract extraction with posterior capsules preserved intact.

eye in humans. In addition, Osterlin 10 found a striking difference between intra- and extracapsular surgery in terms of hyaluronic acid concentration changes in experimental animals. When ICCEs were performed in owl

Fig 16. Top left, posterior vitreous detachment (arrow) in eye following ICCE surgery. Top center and right, gross appearance of retinal pits (arrowheads) in a mid peripheral, perivascular location. Bottom left, retinal pits (arrowheads) adjacent to retinal vessels (E.P. 54130, periodic acid-Schiff, x 100).

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Fig 18. Retinal tear in eye after intracapsular cataract extraction. Top. equatorial horseshoe retinal tear showing posterior (arrowhead) and anterior (arrow) margins. Vitreous (asterisk) remains attached to anterior margins of tear (E.P. 58096, hematoxylin-eosin, X30). Bottom. higher power demonstrates vitreous (arrow) that has detached posteriorly but remains attached to anterior margin of horseshoe tear (periodic acidSchiff, X55).

Fig 17. Top. retinal holes (large arrowheads) and retinal pits (small arrowheads) in equatorial retina following intracapsular cataract extraction (E.? 53366). Middle lefl. horseshoe retinal tear (arrowhead) (E.? 54134). Middle right. section through tear in same eye demonstrates posterior (arrowhead) and anterior (arrow) margins of horseshoe tear (hematoxylineosin, X 110). Bottom. higher power of tear in same eye shows anterior margin of tear with vitreous (arrowheads) attached (hematoxylin-eosin, X200).

monkeys, there was a rapid 90% reduction in hyaluronic acid concentration in the vitreous. This contrasted sharply with the findings after ECCE surgery (with the posterior capsule left intact) in which hyaluronic acid concentration remained virtually unchanged. Analysis of vitreous from human aphakic eyes has revealed a 63% reduction in hy-

aluronic acid concentration after ICCE surgery and only a 16% reduction after ECCE surgery (Osterlins, Kangro M, written communication, May 1984). These data support the theory that presentation of an intact posterior capsule reduces loss of hyaluronic acid from the vitreous with attendant vitreous degeneration and posterior vitreous detachment. In our study, we found no difference in frequency of posterior vitreous detachment between ICCE and ECCED eyes. We concluded that our findings point to the importance of an intact posterior capsule in reducing the frequency of posterior vitreous detachment and that loss of hyaluronic acid, rather than mechanical displacement of the vitreous body, is more important in accounting for the lower frequency of posterior vitreous detachment of ECCE-CI eyes. )

Fig 20. Cystoid macular edema and macular hole in eyes after ICCE. Top tefl. cystic spaces located in the inner nuclear and outer plexiform layers (E.? 52838, hematoxylin-eosin, X50). Top right. higher power of Fig A shows cystic spaces with only traces of proteinaceous material (hematoxylineosin. X21 0). Bottom lefi. macular hole. The margins are rounded and there is a 0.5 mm zone of partial degeneration of the photoreceptor cell layer on either side (E.? 51638, hematoxylin-eosin, X50). Bottom middle. higher power of temporal rounded margin of macular hole (E.? 51638, hematoxylin-eosin, X200). Bottom right. higher power of nasal rounded margin of macular hole (E.P. 51638, hematoxylin-eosin, X200).

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Fig 19. Posterior vitreous detachment with traction on retina in eye after intracapsular cataract extraction. Top. posteriorly detached vitreous (asterisk) exerts traction on equatorial retina at site of attachment (arrowhead) (E.P. 48367, periodic acid-Schiff, X 110). Bottom. higher power shows retina in a tented-up configuration by vitreous traction (periodic acid-Schiff, X260).

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Fig 21. Lamellar macular hole in eye after intracapsular cataract extraction. Top. inner lamellar defect of foveal area. A preretinal membrane (arrowheads) extends to either side (E.P. 58096, periodic acid-Schiff, X35). Middle, temporal margin oflamellar hole shows a pigmented preretinal membrane (arrowhead) with slight wrinkling of the internal limiting membrane (arrow) (periodic acid-Schiff, X400). Bottom, nasal margin shows hypocellular preretinal membrane (arrowheads) that has apparently contracted and caused wrinkling of the internal limiting membrane of the retina (arrow) (periodic acid-Schiff, X400).

It might be anticipated, as a consequence of a lower frequency of posterior vitreous detachment, that ECCECI eyes should have lower rates of those complications

Table 5. Eyes With Posterior Vitreous Detachment Operation Performed

Male Female White Black

ICCE

ECCE-D

ECCE-CI

61 (80%) 59 (87%) 114(84%) 6 (67%)

7 (70%) 12 (80%) 19 (76%)

5 (36%) 7 (47%) 11 (39%) 1 (50%)

o

IGGE = intracapsular cataract extraction: ECCE-D = extracapsular cataract extraction with surgical discission; ECCE-CI = extracapsular cataract extraction with posterior capsules preserved intact.

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Fig 22. Preretinal membranes with associated wrinkling of internal limiting membrane in eyes after intracapsular cataract extraction. Top, preretinal membrane (arrowhead) continuous with optic nerve head has contracted and produced wrinkling of the internal limiting membrane (arrow) (E.P. 54130, periodic acid-Schiff, X 100). Top middle, higher power of same eye shows hypocellular preretinal membrane (arrowheads) with wrinkling of the subjacent internal limiting membrane (arrow) (periodic acid-Schiff, X250). Below middle, preretinal membrane (arrowheads) near parafoveal area is continuous with retina at point where internal limiting membrane is absent (right of arrow) (E.P. 54134, periodic acid-Schiff, XII 0). Bottom, higher power of same eye shows preretinal membrane (arrowheads) with two or three layers of cells in some areas and marked wrinkling of the internal limiting membrane (arrows) (periodic acid-Schiff, X220).

thought to relate to vitreoretinal traction, such as peripheral retinal breaks, cystoid macular edema, and preretinal membranes. Sanders et aI, II in a randomized masked prospective study of288 patients who underwent uncomplicated ECCE and posterior chamber lens implantation, found that primary surgical capsulotomy was associated with a significantly higher incidence of angiographically confirmed cystoid macular edema. No statistically significant differences in the frequency of peripheral retinal or macular lesions were demonstrated, however, between ICCE, ECCE-D, and ECCE-CI eyes in our study. This negative finding does not necessarily minimize the importance of a lower frequency of posterior vitreous detachment in ECCE-CI eyes. Probably our series is much

McDONNELL, et al • CATARACT SURGERY COMPARISON

too small to allow detection of statistically significant differences in rates which are as low as the frequency of cystoid macular edema and retinal hole formation. Only properly designed large clinical studies will be able to establish whether such differences do exist.

ACKNOWLEDGMENT Cheryl L. Auer, MS, of the Wilmer Institute Biostatistical Center assisted with the statistical analysis.

REFERENCES 1. Moses L. Cystoid macular edema and retinal detachment following cataract surgery. Am Intraocullmplant Soc J 1979; 5:326-9. 2. The Miami Study Group. Cystoid macular edema in aphakic and pseudophakic eyes. Am J Ophthalmol1979; 88:45-8. 3. Jaffe NS, Clayman HM , Jaffe MS. Retinal detachment in myopic eyes after intracapsular and extracapsular cataract extraction. Am J Ophthalmol1984; 97:48-52.

4. Beyer TL, Vogler G, Sharma D, O'Donnell FE Jr. Protective barrier effect of the posterior lens capsule in exogenous bacterial endophthalmitis-an experimental primate study. Invest Ophthalmol Vis Sci 1984; 25:108-12. 5. Friedman Z, Neumann E, Hyams S. Vitreous and peripheral retina in aphakia; a study of 200 non-myopic aphakic eyes. Br J Ophthalmol 1973; 57:52-7. 6. Hauer y, Barkay S. Vitreous detachment in aphakic eyes. Br J Ophthalmol1964; 48:341-3. 7. Jaffe NS, Light DS. Vitreous changes produced by cataract surgery; a study of 1,058 aphakic eyes. Arch Ophthalmol 1966; 76:541-53. 8. Foos RY. Posterior vitreous detachment. Trans Am Acad Ophthalmol Otolaryngol1972; 76:480-97. 9. Heller MD, Straatsma BR, Foos RY. Detachment of the posterior vitreous in phakic and aphakic eyes. Mod Probl Ophthalmol 1972; 10: 23-36. 10. Osterlin S. Vitreous changes after cataract extraction. In: Freeman HM, Hirose T, Schepens CL, eds. Vitreous Surgery and Advances in Fundus Diagnosis and Treatment. New York: Appleton-Century-Crofts, 1977; 15-21. 11. Sanders D, Kraff M, Jampol L, Lieberman H. Effect of posterior capsule status on the incidence of pseudophakic cystoid macular edema following posterior chamber lens implantation. ARVO Abstracts. Invest Ophthalmol Vis Sci 1984; 25 (Suppl): 2.

Discussion by Robert Y. Foos, MD The subject of this report is both timely and important and the results, if confirmed, will have direct clinical application. The authors are to be commended for the comprehensiveness with which they documented the postoperative complications found with the limbal wounds and in the anterior segment. This information will be appreciated by anterior segment surgeons. Regarding the vitreoretinal findings, however, I have some questions and comments. The authors indicate that the interval between surgery and death was unknown in most cases of their series. However, did they statistically analyze those cases in which the duration of surgical aphakia was known? Most of the existing information about the temporal aspects of posterior vitreous detachment (PVD) following cataract extraction is anecdotal or speculative. Accordingly, even their small numbers may offer an opportunity to statistically derive meaningful information on this important subject. The authors do not mention fellow eyes in either the "material" or "results" sections of the manuscript. Unilateral surgical aphakic cases are especially valuable as study material, since the phakic eye serves as an "internal control" for many important parameters. Accordingly, this information could be an 'important adjunct to the report. While it has become a practice in most laboratories to process pseudophakic eyes with intraocular lenses in situ (by adding chloroform to the processing solutions to soften the plastic), processing information is not included in the report. The alternative technique, removal of the lenses prior to processing, could be a source of misleading alterations, especially if "surgical discission" of the posterior capsule is interpreted on the basis of microscopic findings. From the Department of Pathology, Jules Stein Eye Institute, UCLA School of Medicine, Los Angeles.

Because of its causal relationship to rhegmatogenous retinal detachment, PVD is a critical piece of data in this study. At UCLA we have emphasized the value of suspension-in-air technique to evaluate the vitreous in enucleated eyes, since assessment microscopically can be difficult, even with special stains. I Accordingly, I wonder how PVD was determined by the authors. For example, the two gross photographs (Figs. 3, 16) used to illustrate PVD by the authors clearly show vitreous on the surface of the post-equatorial retina. Also, in how many cases were the gross specimens studied by the authors personally? Misinterpretations of the attachments of the vitreous in the posterior fundus on gross examination are commonly made by inexperienced observers in my laboratory. For example, postmortem detachment of the inner limiting lamina in the posterior fundus is often confused with PVD (Fig I). This artefact relates to the lack of attachment plaques between the inner limiting lamina and the underlying Muller cells in the postequatorial retina in man. 2 Additionally, PVD may be misdiagnosed if the anterior wall of a large synchytic cavity is mistaken for the detached posterior hyaloid (Fig 2). The authors seem to be aware of these problems, since they allude to them in their essay, but it would be helpful if they provided more specific information in the "methods" section of their report. It would be helpful also in interpreting the authors statistical data on PVD if they would provide more information concerning their cases. How many were female, since PVD is known to occur more commonly in women. I What was the ethnological representation in their series, since certain racial and cultural groups are known to be predisposed to ocular trauma, which also is a known cause of PVD. Finally, did any of the patients have a history or stigmata of diabetes mellitus, ocular trauma, or ocular inflammation, since all are associated with PVD. How was "surgical discission" determined by the authors? Since they indicate that the interval between surgery and death

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Fig 1. Pseudo-posterior vitreous detachment; large calotte, horizontally sectioned right eye of a 59-year-old man, autopsied ten hours after death. Left, specimen posteriorly suspended-in-air. Arrowheads mark cut edge of inner limiting lamina,2 which is detached throughout the posterior fundus and simulates a detached posterior hyaloid and partial PYD (X5). RighI, specimen submerged in alcohol with oblique lighting. Arrow indicates detached thick "glass" membrane (inner limiting lamina2) in posterior fundus (X4.6).

Fig 2. Pseudo-posterior vitreous detachment (PVD); large calotte, vertically sectioned right eye of a 64-year-old woman, autopsied 18 hours after death. Arrows mark anterior wall ofiarge synchytic cavity simulating detached posterior hyaloid and complete PVD. Arrowhead indicates glassy highlights from thin residual layer of vitreous on retina in posterior fundus (X4.6).

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CATARACT SURGERY COMPARISON

was unknown in most cases, we must assume that operative records were not generally available and that "surgical discission" of the lens capsule must have been determined on pathologic examination. In this regard it is to be noted that the authors use the double-cal otting method of gross dissection, which can be very traumatic, especially in inexperienced hands. Also I wonder how many of the specimens were prosected by the authors and how many by trainees? In my own laboratory all surgically aphakic eyes are cut either by me personally or by an experienced fellow. We routinely open eyes with a single calotte technique to minimize trauma. Notwithstanding, my concern about artefactual changes is such that in studying surgically aphakic eyes, I now use an equatorial incision in the coronal plane. This procedure is essentially atraumatic and permits direct in situ examination of the postiridal region, which is very helpful when intraocular lenses are present. Additionally, we now use a slit lamp to examine the posterior capsule for defects. Processing of paraffin-embedded specimens, especially those containing intraocular lenses, can also lead to artefactual changes that may be difficult to interpret microscopically. Finding four macular holes in a series of 20 1 eyes is surprising. In over 400 surgically aphakic eyes we are currently studying, we have found only two eyes with macular holes, and predisposing conditions were present in both cases; one had proliferative diabetic retinopathy with significant tractional changes in the macular region, and the other had sustained blunt ocular trauma in the past. One wonders whether the cases in the present

series had predisposing circumstances other than the surgical aphakia; again, it may be illuminating if the authors would provide ethnological information. It would also be useful to know the distribution of these eyes in the three study groups, since trauma is an important cause of both macular holes and PVD and this could have biased the PVD statistical analysis. Finally, for one who has had a long-term special interest in degenerative lesions of the peripheral fundus in man, I am troubled by the inconsistent terminology used by the authors in the classification of retinal breaks in this essay. Tears are tractional lesions of major significance in the pathogenesis of rhegmatogenous retinal detachment, while holes are of trophic origin and much less commonly a cause of detachment. 3,4 If the results of this study are confirmed, notably the beneficial effects of an extracapsular cataract extraction (with intact posterior capsule) in preventing PVD and macular edema, this information will be gratefully received by cataract surgeons. References 1. Foos RY, Wheeler NC. Vitreoretinal juncture; synchysis senilis and posterior vitreous detachment. Ophthalmology 1982; 89: 1502-12. 2. Foos RY. Vitreoretinal juncture; topographical variations. Invest Ophthalmol1972; 11 :801-8. 3. Foos RY. Postoral peripheral retinal tears. Ann Ophthalmol 1974; 6: 679-87. 4. Foos RY. Retinal holes. Am J Ophthalmol1978; 86:354-8.

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