Pars Plana Incisions of Four Patients

486 British Journal of Ophthalmology 1995; 79: 486-493 Pars plana incisions of four patients:

histopathology and electron microscopy Br J Ophthalmol: first published as 10.1136/bjo.79.5.486 on 1 May 1995. Downloaded from

Frank H Koch, Allan E Kreiger, Manfred Spitznas, Ben Glasgow, Robert Y Foos Marc 0 Yoshizumi

Abstract with the diagnosis of extramacular disciform The pathology of pars plana incisions of degeneration. During follow up the intraocular four patients is described: three with light lesion was observed to grow in size and he microscopy and one with light and elec- underwent biopsy to rule out melanoma. tron microscopy. Two eyes were removed A standard three port pars plana vitrectomy because of choroidal melanoma, immedi- was performed with the Microvit. Sclerotomies ately and 8 days after vitrectomy and were made with a myringotomy knife and the transvitreous retinal biopsy. Considerable biopsy was accomplished by passing a 25 disruption oftissues surrounding the pars gauge needle through the superonasal incision plana incisions was observed. Vitreous into the tumour and aspirating forcefully. was incarcerated in the wounds, which Malignant melanoma ofthe choroid was found healed with granulation tissue. One eye on cytopathological examination. The surgical was examined 4 months after vitrectomy incisions were closed with interrupted 7-0 for diabetic retinopathy and a failed pars polypropylene sutures after careful removal of plana filtering operation. It contained vitreous from the wounds with cellulose fibrovascular ingrowth from all the in- sponges and scissors. The eye was then cisions, infiltrating the vitreous base with enucleated immediately (according to the granulation tissue and causing vitreous wishes ofthe patient). The specimen contained haemorrhage and retinal detachment. a moderate sized, flat, malignant melanoma of One eye was removed 1 year after vitrec- the choroid. Following fixation in formalin, the tomy for anterior hyaloidal fibrovascular wounds were serially sectioned and examined proliferation and early phthisis. The with light microscopy. wound had fibrous ingrowth histologically and evidence ofactive fibroplasia. (BrJ Ophthalmol 1995; 79: 486-493) PATIENT 2 The patient, a 26-year-old woman, was first http://bjo.bmj.com/ seen at 5 years of age and found to have a Information regarding the pathology of pars normal eye at examination. At age 7 years she plana incisions is limited. The relation of was found to have a macular lesion in the right wound healing to other clinically disruptive eye which, after extensive consultation, was fibroplastic processes within the eye, such as believed to be a Toxocara granuloma. The fibrous ingrowth, anterior hyaloidal fibro- lesion was unchanged until age 24 years when vascular proliferation, and proliferative vitreo- it was thought to be enlarging. Observation of on September 23, 2021 by guest. Protected copyright. retinopathy, is unclear. the mass over the next year confirmed its Unfortunately, specimens often reach the growth. The vision dropped to bare light per- pathologist late in the clinical course of disease ception because of secondary retinal detach- because of enucleation for severe complica- ment. Because of concern that the lesion might tions of the previous vitrectomy or of the be malignant, a diagnostic fine needle aspira- Department of Ophthalmology, underlying disease. By this stage significant tion was performed. University of Bonn, intraocular scarring and anatomical dis- A standard three port vitrectomy was carried Germany, Alfiied organisation may confound interpretation and out with the Microvit. Sclerotomies were Krupp Laboratory obscure the F H Koch histological relations. Further- made with a myringotomy knife. Biopsy of the M Spitznas more, clinical correlation is often lacking. lesion was accomplished with a 25 gauge This paper reports on the pathological find- needle inserted through the superotemporal Department of ings in four patients: three studied with light in the same manner as in Ophthalmology, UCLA sclerotomy patient 1. School ofMedicine microscopy and one with light and electron The superior incisions were closed with A E Kreiger microscopy. Two eyes were enucleated soon running 8-0 nylon sutures after meticulous M 0 Yoshizumi after the vitreous procedure, another 4 months resection of vitreous in the wound with Department of later, and the last 1 year after vitrectomy. The cellulose sponges and scissors. The infusion Pathology, UCLA findings offer some insights into the spectrum cannula was withdrawn and the inferotemporal School ofMedicine of pathological changes that may occur during incision was closed with a purse string 6-0 B Glasgow R Y Foos the healing of sclerotomies. polypropylene suture. Malignant melanoma of the choroid was Correspondence to: Frank H J Koch, MD, established on cytopathological examination of Universitats-Augenklinik, Material and methods the aspirate. The eye was enucleated 8 days Sigmund-Freud-Strasse 25, 53105 Bonn, Germany. later and fixed in formalin. The specimen con- PATIENT 1 tained a Accepted for publication moderate sized malignant melanoma 10 January 1995 The patient, a 65-year-old man, was referred of the choroid of mixed cell type in the Pars plana incisions offourpatients: histopathology and electron microscopy 487

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Figure 1 The superotemporal incision ofpatient 1 showing internal gaping ofthe scieral wound, andfragmented ciliary stroma prolapsing around the cut edge ofciliary epithelium into the vitreous (arrowhead) and displaced into the closed portion of the scleral wound (double arrowhead). S=sclera, U=uvea, http://bjo.bmj.com/ V=vitreous (hdematoxgylin and eosin, x200). Figure 2 The superonasal incision ofpatient 1 showing vitreous incarcerated in the scleral portion of the incision (arrowheads). S=sclera (haematoxylin and eosin, x SSO). Figure 3 The superonasal incision ofpatient 2 showinggap in ciliary epitheliumfilled withfibrocellular tissue (arrowhead). S=sclera, U=uvea, CE=ciliary epithelium, V=vitreous (haematoxylin and eosin, x200). Figure 4 The superonasal incision ofpatient 2 showingfibrocellular tissue extending into scleral incision (arrowheads). S=sclera (haematoxylin and eosin, X350). Figure 5 The superotemporal incision ofpatient 2 showingfibrocellular tissue growing along vitreousfibrils (arrowhead) and into scleral wound (double on September 23, 2021 by guest. Protected copyright. arrows). S=sclera, CE=ciliaty epithelium (haematoxylin and eosin, x350). posterior pole. The incisions were serially sec- pain and requested enucleation 4 months later. tioned and examined with the light micro- The eye was fixed in formalin and prepared for scope. light microscopy.

PATIENT 3 PATIENT 4 The patient, a 36-year-old white woman with The patient is a 63-year-old man with severe diabetes mellitus, developed vitreous haemor- diabetic retinopathy, vitreous haemorrhage, rhage and rubeotic glaucoma bilaterally and rubeosis iridis who underwent pars plana despite panretinal photocoagulation. She vitrectomy with the Microstripper and a three underwent a pars plana vitrectomy, lensec- port system. In the immediate postoperative tomy, and planned pars plana filtering opera- period the patient had recurrent vitreous tion with the Ocutome three port system. The haemorrhages and lost light perception over superonasal and inferotemporal incisions were several weeks. A diagnosis of anterior hyaloidal closed with 8-0 nylon. The superotemporal fibrovascular proliferation (AHFP) was made incision was made under a scleral flap as in a clinically. The eye developed phthisis bulbi trabeculectomy and the opening in the sclera and required enucleation for pain 1 year after was widened at the end ofthe procedure with a the vitrectomy. The eye was bisected immedi- scleral punch. The scleral flap was then closed ately and fixed for electron microscopy by over the inner opening. immersion in 2-5% glutaraldehyde and 2% Postoperatively the intraocular pressure was paraformaldehyde buffered with 0 1 M sodium controlled temporarily; however, the glaucoma cacodylate pH 7-2. Gross examination returned and the patient developed intractable revealed a total retinal detachment with 488 Koch, Kreiger, Spitznas, Glasgow, Foos, Yoshizumi Br J Ophthalmol: first published as 10.1136/bjo.79.5.486 on 1 May 1995. Downloaded from

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Figure 6 The superotemporal, pars planafiltering incision the ciliary epithelium into the vitreous cavity ofpatient 3 showing a largeflat scar spreading along the (Fig 1). pars plana (arrowhead). S=sclera, P=pars plana (X 10). Vitreous was incarcerated in the incision and

Figure 7 The eye ofpatient 3 showing superotemporal, Br J Ophthalmol: first published as 10.1136/bjo.79.5.486 on 1 May 1995. Downloaded from filtering incision (white arrowhead) and the superonasal could be seen in the internal aspect ofthe uveal incision (black arrowhead). Note the posterior traction scleral fissure (Fig 2). causing a peripheral retinal detachment (asterisk) (x3). The surrounding uveal stroma showed mild Figure 8 The superotemporal, filtering incision in patient regional congestion and mild focal haemor- 3 showing the open sclerostomy within the sclera (arrow), thefibrovascular tissue occluding the internal opening ofthe rhage. Profiles of suture material were present sclerostomy (small asterisk), and the massive accumulation in the mid sclera. offibrovascular tissue present in the vitreous (large asterisk) corresponding to the white scar seen grossly. Numerous blood vessels are seen within the scar (small arrowheads). S=sclera, U=uvea (haematoxylin and PATIENT 2 eosin, X 80). The findings in patient 2, whose wounds were Figure 9 The superonasal vitrectomy incision in patient 3 8 days old, varied from those in patient 1, showing thefibrovascular tissue extendingfrom the that the process of repair had begun sclerotomy (small asterisk) into the vitreous to become indicating continuous with afibrovascular ingrowth (large asterisk). in the 8 days since vitrectomy. The retrolental membrane reaches posteriorly as well along Scleral apposition was better than in patient the surface ofthe residual vitreous. Blood vessels 1 and suture profiles were noted in the deep (arrowheads) are present within the ingrowth and vitreous haemorrhage is present (arrow). S=sclera, V=vitreous sclera. Only mild gaping of the internal scleral cavity (haematoxylin and eosin, X 80). margins was noted centrally. As in patient 1, a Figure 10 The superonasal vitrectomy incision in patient moderate sized gap was noted in the ciliary 3 showing blood vessels with the sclera (arrowheads) which epithelium (Fig 3). This region was filled with could be traced to anastomose with the episcleral vessels and the vessels ofthefibrovascular ingrowth. S=sclera, numerous cells embedded in an eosinophilic U=uvea (haematoxylin and eosin, X 80). material with slightly fibrillar appearance Figure 11 The peripheral retinal detachment (Fig 4). superonasally in patient 3. Fibrovascular tissue The cells had prominent nuclei and indis- (arrowhead) extends posteriorly along the vitreous surface tinct cell borders except in the vitreous zone, to the posterior aspect ofthe vitreous base (asterisk) which is pulledforvard to cause a tractional retinal detachment. where they became more spindle shaped and No blood vessels were noted to extendfrom the retina into appeared to conform to vitreous strands the vitreous base. R=retina, P=pars plana (haematoxylin entering the wound area (Fig 5). Cells were and eosin, x 80). noted to stream from the vitreous aspect of the wound into the scleral incision for a short dis- tance (Figs 4 and 5). retrolental scarring and intraocular haemor- Vitreous was adherent to and enmeshed rhage. The findings were felt to be consistent in the scar tissue and cells were growing with the diagnosis of AHFP. One pars plana along fibrils into the vitreous substance (Figs 3 incision could be identified grossly and it was and 5).

removed from the specimen with surrounding http://bjo.bmj.com/ tissue and postfixed in 2% osmium tetroxide veronal in cacodylate buffer. After staining PATIENT 3 with 2% uranyl acetate and dehydration in In the eye ofthe third patient there was profuse acetone, the tissue was embedded in Araldite. fibrovascular scarring in the pars plana region, Sections were cut with a diamond knife for centred around the sclerotomies and extending light microscopy and for electron microscopy into the residual collapsed vitreous body. after treatment with uranyl acetate and lead Grossly, the superotemporal wound, where on September 23, 2021 by guest. Protected copyright. citrate. the pars plana filtering operation had been performed, had a flat, white scar reaching from its centre onto the pars plana (Fig 6). The Results superonasal incision had less severe scarring, Patients 1 and 2 exemplify those findings but there was contiguous vitreous haemor- present early after uncomplicated pars plana rhage and traction posteriorly causing a vitrectomy in eyes that are normal except for peripheral retinal detachment (Fig 7). The intraocular tumour. At the other end of the inferotemporal incision had less scarring as spectrum, patients 3 and 4 demonstrate well. those findings in eyes of patients with end Microscopically the superotemporal scleros- stage diabetes that are removed after vitrectomy was open within the sclera, but fibro- tomy. vascular tissue occluded the opening at the uveal aspect (Fig 8). The other incisions were closed along their entire length. A massive PATENT 1 accumulation of fibrous tissue, containing Significant findings in the first patient were large blood vessels, was present in the vitreous, similar in each of the incisions. Superficial corresponding to the white tissue seen grossly. scleral apposition was sufficient, but mild to In the superonasal incision (Fig 9) a large moderate gaping of the internal aspect of the gap in the ciliary epithelia was present from scleral wound was present in certain portions which fibrovascular tissue extended internally. of the incision. The defect in the ciliary epithe- The ciliary body and uveal stromal architec- lium was fairly large in each case as was the gap ture were disorganised in the central scar. in the uveal stroma. Ciliary muscle and stroma More peripherally, where the uveal structure were fragmented at the wound edge and resumed its normal appearance, blood strands of tissue flowed around the defect in vessels were markedly dilated. Large vascular 490 Koch, Kreiger, Spitznas, Glasgow, Foos, Yoshizumi Br J Ophthalmol: first published as 10.1136/bjo.79.5.486 on 1 May 1995. Downloaded from .e.

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Figure 12 The superotemporal vitrectomy incision of carried out (Fig 12). The wound site could be patient 4. Fibrovascular tissue extends as a tract (asterisk) from the episclera into the vitreous cavity through a defect identified easily by the discontinuity in the in the ciliary epithelium. A large vein is seen to transit the regular pattern of the scleral fibrils. A stalk of sclerotomy and connects with episcleral vessels and fibrous tissue extended from the episclera into Br J Ophthalmol: first published as 10.1136/bjo.79.5.486 on 1 May 1995. Downloaded from intravitreous vessels as well (arrow). An artery is also a wide present which anastomoses with vessels in the ciliary body the vitreous cavity through moderately (arrowhead). Proliferating ciliary epithelium is present in opening in the ciliary epithelium. Here it the vitreous at the posterior aspect ofthe incision (double branched anteriorly and posteriorly. Dilated asterisk). S=sclera, U=uvea, CE=ciliary epithelium, blood vessels within the ciliary body could be V=vitreous (methylene blue, X50). traced to enter the fibrous trunk extemally and Figure 13 A fibroblast in loose collagenfrom the episcleral tissue ofpatient 4 (electron microscopy, X 3000). to course with it into the vitreous scar. A large Figure 14 The intrascleral portion ofthe incision consisted artery in the vitreous fibrous tissue was found ofbundles ofcollagen andfibroblasts runningparallel to the to anastomose with vessels in the ciliary body axis ofthe wound (electron microscopy, x3000). (Fig 12). In the centre of the scar a large vein Figure 15 A single myofibroblast was noted in the was followed from the vitreous cavity through subepithelial portion ofthe scar (electron microscopy, the stalk and through the sclerotomy to the X 12 000). episcleral blood vessels. At this point fibrous Figure 16 The intravitreous portion ofthe scar contained fibroblasts andplasma cells (arrowhead) (electron tissue from the episclera could be seen to microscopy, X2200). stream along the walls of the vein, through the Figure 17 The posterior aspect ofthe vitreous scar, lying sclerotomy, and into the substance of the next to the ciliary epithelium contained capillaries (arrows), intraocular fibrous trunk (Fig 12). plasma cells (double arrowhead), andfibrous tissue (electron microscopy, X 700). Electron microscopic examination concen- Figure 18 Myofibroblasts were present in the posterior trated on several areas ofinterest: the episcleral aspect ofthe vitreous scar and contained prominent rough tissue, the intrascleral portion of the incision, endoplasmic reticulum and intracytoplasmicfibrils (arrows) and the tissue within the vitreous cavity. (electron microscopy, X 12 000). The episcleral tissue external to the Figure 19 Desmosomes were noted between adjacent incision consisted of mature collagen and myofibroblasts (arrowhead) (electron microscopy, X20 000). fibroblasts arranged in a less regular, looser Figure 20 J7unctional complexes (arrowhead) and pattern (Fig 13). basement membraneformation (double arrowhead) were The intrascleral portion of the incision con- prominentfeatures ofthe epithelium cells (electron sisted mainly of bundles of collagen, generally microscopy, X30 000). running parallel to the axis of the wound Figure 21 Degenerating myofibroblasts were noted in the had the characteristic vitreous scar anterior to the incision in patient 4 (electron (Fig 14). The collagen microscopy, X8800). 64 nm banding of type I (adult) collagen. Figure 22 Blood vessels located in the centralportion of Embedded in the fibrils were mature appearing the anterior vitreous scar did not show endothelial fibroblasts (Fig 14). A single myofibroblast, fenestrations (arrowhead). L=lumen of vessel (electron generally resembling a fibroblast but with microscopy, X4400). prominent myofibrils and rough endoplasmic

Figure 23 The ciliary epithelia in the anterior region were http://bjo.bmj.com/ separated into two layers by a zone ofloose connective reticulum, was seen in the subepithelial tissue. CE=ciliary epithelium vessel (arrow) (electron portion of the scar (Fig 15). The electron microscopy, X300). microscopic features of the large artery and Figure 24 The vessels in the loose connective tissue vein which accompanied the intrascleral scar exhibited pores in the endothelium (arrowhead). L=lumen in resembled the ofvessel (electron microscopy, X20 000). were unremarkable that they structure of similar sized vessels. Figure 25 Sheets ofepithelial cells (asterisk) extended normal, centrally into the inflammatory cells in the retrolental In the intravitreous portion of the lesion gap portion ofthe vitreous (electron microscopy, X250). of ciliary epithelia, the fibrous tissue became on September 23, 2021 by guest. Protected copyright. Figure 26 The epithelial cells had basement membrane more cellular as it fanned out onto the surface material on theirfree surface (arrowhead) along with an ofthe ciliary body. Fibroblasts and plasma cells abundance offibrils (asterisk) (electron microscopy, X 12 000). were present (Fig 16). Posteriorly, in the layer of scar lying next to the ciliary epithelium (Fig 17), myofibroblasts were present with axially channels in the sclera were noted which could oriented intracytoplasmic fibrils and prominent be traced to the vessels in the sclerotomy scar rough endoplasmic reticulum (Fig 18). In and to vessels in the episclera (Fig 10). places discontinuous basement membrane The remaining vitreous was collapsed material was present and desmosomes were markedly and was drawn anteriorly to become seen (Fig 19). A few capillaries with non-fenes- continuous with a retrolental membrane. The trated endothelium were present (Fig 17). posterior aspect ofthe vitreous base was pulled Collagen structure was similar to that noted forward, causing the peripheral retina to deeper in the wound, and scattered plasma cells detach (Fig 11). The subjacent peripheral were present (Fig 17). Nearer to the vitreous choroid was also detached. No blood vessels cavity there was a collection of epithelial cells in were identified to arise from the peripheral the fibrous scar. These cells had prominent retina nor were vessels seen to enter the resid- nuclei, abundant cytoplasm, basement ual lens capsule. Fibrovascular tissue from the membranes, organelles, and cellular junctions sclerotomy extended into the vitreous to typical of epithelial cells (Fig 20). become a part of the retrolental scar. Anterior to the wound the vitreous cavity was more infiltrated with fibrocellular tissue and the ciliary epithelia were more distorted PATIENT 4 and displaced vitread. The density of fibro- Light microscopy of serial sections through cellular material was greatest just behind the the superotemporal vitrectomy incision was lens, and small pockets of inflammatory cells 492 Koch, Kreiger, Spitznas, Glasgow, Foos, Yoshizumi

were present. Fixation in this region was Concern over the possibility of this occurring poorer than in the rest of the specimen, sug- regularly from pars plana incisions was voiced gesting that degeneration or necrosis of tissue in the early days of vitreous surgery.23 24 had occurred. At higher magnification, areas of Fortunately, fibrous ingrowth causing signifi- Br J Ophthalmol: first published as 10.1136/bjo.79.5.486 on 1 May 1995. Downloaded from fine fibrils, most probably collagen, were seen cant intraocular problems after vitrectomy has to intermingle with elongated structures con- been rare.1 2 25-27 taining microfilaments inserting into dense The term fibrous ingrowth, however, is plaques (Fig 21). More centrally, varying poorly defined and can causel 2 25-27 con- amounts of clear matrix and fine fibrils were fusion. All perforations of the pars plana heal present containing vascular structures. These with some degree of fibroplasia or ingrowth of vessels did not show fenestrations (Fig 22). fibrous tissue into the vitreous.15 22 Therefore, The ciliary epithelia in this anterior region the term fibrous ingrowth should be reserved were displaced vitread and separated into two for those cases in which the scarring causes layers. Between these was a zone of loose con- untoward clinical effects. In addition, although nective tissue in which vessels were present the name seems to imply the growth of fibrous (Fig 23). The vessels in this space exhibited tissue into the eye from the episcleral tissues, pores (Fig 24). The origin of these vessels the clinically important aspect of fibrous could not be determined. The non-pigmented ingrowth is that tissue grows from the eye wall ciliary epithelium was contiguous with sheets at the site of an injury into the substance of the of cells extending into the inflammatory tissue vitreous and onto its natural surfaces. Because within the vitreous cavity (Fig 25). These were of the normal connections of the vitreous to arranged in multiple layers in some places, the retina and ciliary body, especially at the and where they had a free surface, basement vitreous base, later contraction of this tissue membrane material was present along with an can result in retinal detachment, ciliary body abundance of fibrils (Fig 26). detachment, and phthisis bulbi. Whether or not the scar arises from the episclera or the wound itself is unimportant in this regard; Discussion however, there is a tendency for clinicians to A number of reports on the pathology of eyes think that poor wound healing or evidence of enucleated after vitrectomy have appeared in tissue entering the eye from without is neces- the literature. 1-11 Some authors have indicated sary to establish the diagnosis of fibrous that their specimens showed limited changes at ingrowth. On the contrary, the scleral portion the site of the pars plana incision and were of a sclerotomy may be well healed and closed not associated with excessive ingrowth of perfectly in the presence ofprofuse ingrowth or tissue into the vitreous cavity.3 4-6 9 10 Others, outgrowth from AHFP of fibrovascular tissue however, have noted early or moderate from the inner portion of the wound into the evidence of fibroplasia from the incision surrounding tissues. causing significant, or potential, ocular compli- Clearly there was excessive fibrous ingrowth http://bjo.bmj.com/ cations.' 2 7 8 11 One brief report describes the of tissue from the routine incision sites as well pathology of the wound in a patient who died as from the sclerostomy in patient 3 (Figs 6 3 weeks postoperatively.10 It is probable that and 7). As expected, there was vitreous most eyes enucleated for complications of haemorrhage and traction retinal detachment. vitrectomy, or of the underlying disease, have The communication of blood vessels from the extensive intraocular disorganisation or episclera into the intraocular fibrous tissue was phthisis bulbi that make them useless in the obvious. Despite the confounding changes on September 23, 2021 by guest. Protected copyright. analysis of the wound sites. wrought by the cyclitic membrane and phthisis The findings in patients 1 and 2 in this series bulbi, the eye of patient 4 also had excessive demonstrate the acute traumatic changes fibrous ingrowth (Fig 12). Again the transit of that may occur in creating, using, and closing blood vessels through the incision was readily surgical pars plana incisions. While it is to be apparent. expected that some tissue damage might occur, Communication of blood vessels through the amount of disruption of the uveal architec- defects in the sclera was observed in monkey ture noted here after simple, straightforward experiments even in simple 25 gauge needle vitrectomy is surprising. incisions; therefore it is not surprising to see Similar findings were demonstrated by blood vessels transiting the incision site in Riffenburgh and Roth in their patient who died these two eyes.12 Such observations alone are 3 weeks after vitrectomy for asteroid hyalosis. not evidence that episcleral tissue has invaded In their case presence ofvitreous in the wound the eye. Nevertheless, the present two cases was highlighted by the asteroid bodies, which (cases 3 and 4) show that the scleral defect could easily be seen grossly and histo- created at the time of surgery can be a pathway logically. 10 for vascular channels to communicate with an The findings in patients 3 and 4 in this series intraocular process. Certainly, if the process is bring up the issues of fibrous ingrowth and active, the vessels might be dilated and visible anterior hyaloidal fibrovascular proliferation clinically. This clinical finding has been (AHFP).79 14 Whereas fibrovascular ingrowth reported previously.' usually is a localised process, AHFP describes No pathological signs of AHFP - namely, a more diffuse process. Fibrous ingrowth and neovascularisation of the anterior retina, were its sequela of retinal detachment and phthisis present in patient 3; however, fibrous ingrowth bulbi have been observed to occur from was present. In patient 4, AHFP was present, perforating ocular injuries for many years.1622 and there was also evidence of ingrowth of Pars plana incisions offour patients: histopathology and electron microscopy 493

site and the 3 Foos RY, Kreiger AE, Nofsinger KD. Pathological study tissue from the sclerotomy following vitrectomy for proliferative diabetic retinopathy. presence of blood vessels in the scleral portion Retina 1985; 5: 102-6. of the otherwise well healed incision. 4 Buettner H, Machemer R. Histopathologic findings in

human eyes after pars plana vitrectomy and lensectomy. Br J Ophthalmol: first published as 10.1136/bjo.79.5.486 on 1 May 1995. Downloaded from This leaves the question of how fibrous Arch Ophthalmol 1977; 95: 2029-33. In 5 Michels RG. Vitreous surgery. St Louis: Mosby, 1981: 399. ingrowth and AHFP relate to one another. 6 Weinberg RS, Peyman GA, Apple D. Histopathology after their article on the pathology of AHFP, Lewis vitrectomy with the vitreophage. Graefes Arch Clin Exp Ophthalmol 1975; 196: 133-42. et a19 stress that the two entities are different 7 Elner SG, Elner VM, Diaz-Rohena R, MacKenzie Freeman clinically and pathologically. In the two eyes H, Tolentino Fl, Albert DM. Anterior proliferative vitreoretinopathy. Clinicopathologic, light microscopic, and that they studied, they found that 'the surgical ultrastructural findings. Ophthalmology 1988; 95: sclerotomy wounds were well healed without 1349-59. thereby excluding 8 Elner SG, Elner VM, Freeman HM. The pathology of excess proliferative tissue, anterior (peripheral) proliferative vitreopathy. Trans Am fibrovascular ingrowth as a cause for fibro- Ophthalmol Soc 1988; 86: 330-53. vascular As noted above, how- 9 Lewis H, Abrams GW, Foos RY. Clinicopathologic proliferation'.9 features in anterior hyaloidal fibrovascular proliferation ever, the presence of well healed sclerotomy after diabetic vitrectomy. Am J Ophthalmol 1987; 194: 614-8. wounds does not exclude fibrovascular 10 Riffenbaugh RS, Roth AM. Incarceration of asteroid bodies ingrowth. They also found extraretinal neo- in sclerotomy wound following pars plana vitrectomy. Ophthalmic Surg 1984; 15: 31-3. vascularisation in meridians other than those 11 Kreiger AE, Foos RY, Yoshizumi M. Intravitreous granula- of the sclerotomy sites. tion tissue and retinal detachment following pars plana It appears from their findings, and the injection for cytomegalovirus retinopathy. Graefes Arch Kin Exp Ophthalmol 1992; 230: 197-8. observations in patients 3 and 4, that clinically 12 Kreiger AE. The pars plana incision: experimental studies, significant fibrovascular proliferation in the pathologic observations, and clinical experience. Trans Am Ophthalmol Soc 1991; 89: 549-621. vitreous base can occur and result in complica- 13 Cleary PE, Ryan SJ. Histology of wound, vitreous, and tions such as retinal detachment and phthisis retina in experimental posterior penetrating eye injury in the rhesus monkey. Am J Ophthalmol 1979; 88: 221-3 1. bulbi. Wound healing, evidently contributes 14 Lewis H, Aaberg TM. Anterior proliferative vitreoretinopathy. Am J Ophthalmol 1988; 105: 277-84. variably to the process. There may be instances 15 Kreiger AE. The pars plana incision: experimental studies, where excess fibroplasia from healing of the pathologic observations, and clinical experience. Trans Am Ophthalmol Soc 1991; 89: 549-621. wounds alone is the instigating factor and 16 Barry DR. Pathological changes after trauma. Trans other times when the wounds are related Ophthalmol Soc UK 1975; 95: 340-8. minimally or only passively. Undoubtedly 17 Eagling EM. Perforating injuries involving the posterior segment. Trans Ophthalmol Soc UK 1975; 95: 355-9. there is a spectrum between these two 18 Faulborn J, Topping TM. Proliferation in the vitreous extremes cavity after perforating injury. A histopathologic study. where elements of the two processes Graefes Arch Clin Exp Ophthalmol 1978; 205: 157-66. interact and affect one another. Certainly the 19 Levkoieva ET. The regeneration of wounds of extemal that create the florid membranes of the eye in the light of new pathologico- pathological phenomena anatomic. BrJ Ophthalmol 1947; 31: 336-61. anterior proliferation of tissue from the retina 20 Parsons JH. The healing of wounds of the retina, in AHFP must have some effect on the healing choroid, and sclera with some remarks on the pathology of 'retinitis proliferans'. Roy Lond Ophthalmol Hosp Rep of sclerotomy incisions, which are located in 1903; 15: 215-53. same of the the 21 Winthrop SR, Cleary PE, Minckler DS, Ryan SJ. the region eye. Similarly injury Penetrating eye injuries. A histopathological review. of tissues located in the immediate proximity BrJ Ophthalmol 1980; 64: 809-17. http://bjo.bmj.com/ the involved 22 Spencer WH. Ophthalmic pathology. An atlas and textbook. of the vitreous base and processes Philadelphia: W B Saunders, 1985: 579-81. in the healing of these tissues must have some 23 Kreiger AE, Straatsma BR, Griffin JR, Storm FK, Smiley in the EH. A vitrectomy instrument in stereotaxic intraocular effect on other fibroplastic processes surgery. AmJ Ophthalmol 1973; 76: 527-32. vicinity such as AHFP. Numerous studies 24 Gartner J. In discussion of vitrectomie: instrumentarium the cells and blood derived und operationstechnik by Buettner H, Machemer R, Parel demonstrate that JM. BerDtsch Ophthalmol Ges 1971; 71: 432. substances involved in the repair process are 25 Brockhurst RJ. Complications of closed vitrectomy. In:

Freeman H, Hirose T, Schepens CL, eds. Vitreous surgery on September 23, 2021 by guest. Protected copyright. the major regulators offibroplasia and vascular and advances in fundus diagnosis and treatment. New York: proliferation.'3 28-36 These substances and Appelton Century Crofts, 1977: 377-85. cells are in abundance in fibrocellular 26 Tardif YM, Schepens DL, Tolentino FI. Vitreous surgery. present XIV. Complications from sclerotomy in 89 consecutive tissue which is in direct contact with the cases. Arch Ophthalmol 1977; 95: 229-34. vitreous such as that seen in the normal 27 Kreiger AE. Wound complications in pars plana vitrectomy. base, Retina 1993; 13: 335-44. wounds of patient 2. Furthermore, variations 28 Forrester JV, Lee WR. Cellular composition of posthemor- in anatomical closure of the incision and rhagic opacities in the human vitreous. Graefes Arch Clin Exp Ophthalmol 1981; 215: 279-95. various amounts ofvitreous haemorrhage from 29 Campochiaro PA, Bryan JA, Conway BP, Jaccoma EH. the wound as seen in patient 1 may have an Intravitreal chemotactic and mitogenic activity: implica- tion of blood-retinal barrier breakdown. Arch Ophthalmol influence on the extent and duration of the 1986; 104: 1684-7. repair process. Finally, underlying ocular 30 Campochiaro PA, Gaskin HG, Vinores SA. Retinal cryopexy stimulates traction retinal detachment formation disease (diabetes, vascular occlusion) and the in the presence of an ocular wound. Arch Ophthalmol other injuries sustained at the time of vitreo- 1987; 105: 1567-70. 31 Chen CH, Chen SC. Angiogenic activity of vitreous and retinal surgery (cryotherapy, diathermy, retinal extract. Invest Ophthalmol Vis Sci 1980; 19: photocoagulation, etc) may also influence the 596-602. 32 Forrester JV, Docherty R, Kerr C, Lackie JM. Cellular details of healing of the wounds and inflate proliferation in the vitreous: The use of vitreous explants their importance beyond the usual well con- as a model system. Invest Ophthalmol Vis Sci 1986; 27: 1085-94. tained process that is usually observed.2829 34 33 Johnson RN, Olsen K, Hernandez E. Tissue plasminogen activator treatment of postoperative intraocular fibrin. This work was supported by an award from the Alexander von Ophthalmology 1988; 95: 592-6. Humboldt Foundation to AK and was published in part in 34 Raymond L, Jacobson B. Isolation and identification of fulfilment of requirements for membership in the American stimulatory and inhibatory cell growth factors in bovine Ophthalmological Society. vitreous. Exp Eye Res 1982; 34: 267-86. 35 Sen HA, Robertson TJ, Conway BP. The role ofbreakdown 1 Kreiger AE, Straatsma BR, Foos RY. Incisional complica- of the blood-retinal barrier in cell-injection models of tions in pars plana vitrectomy. Mod Prob Ophthalmol 1977; proliferative vitreoretinopathy. Arch Ophthalmol 1988; 18: 210-23. 106: 1291-4. 2 Puelhorn G, Teichmann KD, Teichmann I. Intraocular 36 Vidaurri-Leal JS, Glaser BM. Effect of fibrin on morpho- fibrous proliferation as an incisional complication in pars logical characteristics of retinal pigment epithelial cells. plana vitrectomy. Am J Ophthalmol 1977; 83: 810-4. Arch Ophthalmol 1984; 102: 1376-9.