A matched study of primary scleral buckle placement during repair of posterior segment open globe injuries.

AIMS: To compare the visual and anatomical outcomes of patients who underwent primary scleral buckle (SB) placement during posterior segment open globe repair with matched control patients who did not undergo primary SB placement. METHODS: Patients who underwent open globe repair alone or with SB placement at Duke University Eye Center (November 1994-September 1997) and the Massachusetts Eye and Ear Infirmary (July 1993-July 1997) were identified. 19 open globe patients who received primary SB placement were matched with control patients who did not receive a primary SB based on three important prognostic factors: (1) visual grade; (2) zone of injury; and (3) mechanism of injury. The outcomes of interest were: (1) visual outcome; (2) anatomical outcome; (3) subsequent retinal detachment (RD); and (4) number of subsequent surgeries. RESULTS: Baseline characteristics between the groups were similar. Patients who received primary SB placement had a better final visual grade (p = 0.02), logMAR vision (p = 0.007), and anatomical grade (p = 0.01) compared with control patients. Primary SB patients had an average final vision of 20/270, whereas control patients had an average final vision of hand movement. Primary SB placement also resulted in fewer subsequent RDs (26% versus 53%), but this difference did not reach statistical significance (p = 0.10). There were no complications associated with primary SB placement. CONCLUSION: Primary SB placement during posterior segment open globe repair may decrease the risk of subsequent RD and improve final visual and anatomical outcome.

Dispase facilitates posterior vitreous detachment during vitrectomy in young pigs.

PURPOSE: To evaluate the role of intravitreal dispase in conjunction with pars plana vitrectomy to facilitate the creation of a posterior vitreous detachment (PVD) in young pig eyes. METHODS: Twenty-four eyes of 24 animals were randomized to receive an intravitreal injection of dispase (50 microg/0.05 mL) or phosphate buffered saline (PBS) immediately after core vitrectomy and before attempted creation of a posterior cortical vitreous detachment. Following a 15-minute waiting period, surgical creation of a posterior vitreous separation was attempted by aspiration of the posterior vitreous immediately adjacent to the optic disk. Eyes were evaluated postoperatively by clinical examination (1, 4, and 8 weeks) and electroretinography (4 and 8 weeks), after which they were enucleated for light, scanning, and transmission electron microscopy. RESULTS: Based on intraoperative findings and postoperative scanning electron microscopy, eyes receiving intravitreal dispase exhibited a higher incidence of PVD compared to eyes receiving PBS (P = 0.029). Electroretinographic responses recorded at postoperative weeks 4 and 8 were similar in both dispase and PBS eyes compared to the unoperated fellow eyes. Clinical examinations, including indirect ophthalmoscopy, were indistinguishable between the PBS eyes and 11 of 12 eyes in the dispase group. Light and transmission electron microscopy demonstrated no differences in the retina between the dispase eyes and the PBS operated controls. CONCLUSION: Dispase is a useful adjunct in facilitating surgical creation of a PVDin young pig eyes.

Pars plana vitrectomy, subretinal injection of tissue plasminogen activator, and fluid-gas exchange for displacement of thick submacular hemorrhage in age-related macular degeneration.

PURPOSE: To evaluate a new procedure for displacement of large, thick submacular hemorrhage in patients with age-related macular degeneration. METHODS: Retrospective review of 11 eyes of 11 patients with age-related macular degeneration and thick submacular hemorrhage (defined as causing retinal elevation detectable on stereo fundus photographs) treated with vitrectomy, subretinal injection of tissue plasminogen activator (25 or 50 microg), and fluid-gas exchange with postoperative prone positioning. Outcome measures included displacement of hemorrhage from the fovea, best postoperative visual acuity, and final postoperative visual acuity. RESULTS: In the 11 affected eyes of 11 patients (seven men and four women; mean age, 76 years), preoperative visual acuity ranged from 20/200 to hand motions. With surgery, subretinal hemorrhage was displaced from the fovea in all 11 cases. Mean postoperative follow-up was 6.5 months (range, 1 to 15 months). Best postoperative visual acuity varied from 20/30 to 5/200, with improvement in nine (82%) cases and no change in two cases. Eight eyes (73%) measured 20/200 or better, with four of these eyes (36%) 20/80 or better. Final postoperative visual acuity ranged from 20/70 to light perception, with improvement in eight (73%) cases, no change in one case, and worsening in two cases. A statistically significant difference was found between preoperative and best postoperative visual acuity (P =.004) but not between preoperative and final visual acuity (P =.16). Hemorrhage recurred in three (27%) eyes, causing severe visual loss in one eye. CONCLUSIONS: This technique displaces submacular hemorrhage from the fovea and can improve vision in patients with age-related macular degeneration. However, recurrence of hemorrhage occurred in 27% of eyes and caused severe visual loss in one eye. A randomized, prospective clinical trial is necessary to determine the efficacy of this technique in comparison with other proposed treatments.

Primary scleral buckling in open-globe injury involving the posterior segment.

PURPOSE: To determine whether scleral buckle placement at the time of primary repair of open-globe injury of the posterior segment is beneficial. DESIGN: Retrospective, comparative, nonrandomized interventional study. PARTICIPANTS: One hundred twenty-five open-globe injuries treated at the Duke University Medical Center from June 1980 to May 1997. METHODS: Open-globe injuries were classified with the Open-globe Injury Classification. Eyes that had zone 2 and 3 injuries that had a primary buckle placed were compared with those that did not. MAIN OUTCOME MEASURES: Subsequent retinal detachment, visual outcome, and need for subsequent scleral buckling. RESULTS: The rate of retinal detachment and the visual outcome were similar in the two groups. More than half of those who did not have a primary buckle placed had subsequent scleral buckling surgery. CONCLUSIONS: Many open-globe injuries of the posterior segment require eventual scleral buckle. There may be a role for placement of a scleral buckle at the time of primary repair.

Features of macular hole closure in the early postoperative period using optical coherence tomography.

PURPOSE: Studying the retina in the early postoperative period after macular hole surgery is difficult because of the limitation of imaging of the fundus through a gas tamponade. Silicone oil was shown recently to be an effective alternative to gas for macular hole repair. The authors hypothesized that optical coherence tomography (OCT) could be performed through silicone oil to study early macular hole closure. METHODS: Fourteen patients with idiopathic full-thickness macular holes underwent repair, including vitrectomy and silicone fill of the vitreous cavity. Silicone oil was removed 5 to 18 weeks later in a second operative procedure. Optical coherence tomography images were obtained preoperatively (n = 14), on the first postoperative day (n = 7), after 1 week (n = 4), after 1 month (n = 14), and after silicone oil removal (n = 14). RESULTS: By the first postoperative day, the retina was flat and the hole was open or closed in all patients. By 1 month, 9 of 14 patients had flat retinas and closed holes, whereas the other 5 patients had flat retinas and open holes. All patients who had an open hole after 1 month had a reopening of the hole after silicone oil removal. CONCLUSIONS: Flattening of the retina with resolution of the foveal cysts after macular hole repair occurs by the first postoperative day. Closure of the horizontal retinal separation is variable but occurs by the first postoperative month in cases of successful macular hole repair. Persistent retinal separation after 1 month may be predictive of hole reopening.

Diagnosis of vitreoretinal adhesions in macular disease with optical coherence tomography.

PURPOSE: To compare the relative incidence of vitreoretinal adhesions associated with partial vitreous separation within the macula diagnosed with optical coherence tomography (OCT) with that of those diagnosed with biomicroscopy. METHODS: The authors obtained linear cross-sectional retinal images using OCT in patients with selected macular diseases. Additional studies included biomicroscopy, fundus photography, fluorescein angiography, and B-scan ultrasonography. RESULTS: Optical coherence tomography was performed on 132 eyes of 119 patients. Vitreoretinal adhesions within the macula were identified using OCT in 39 eyes (30%) with the following diagnoses: idiopathic epiretinal membrane (n = 13), diabetic retinopathy (n = 7), idiopathic macular hole (n = 7), cystoid macular edema (n = 7), and vitreomacular traction syndrome (n = 5). Biomicroscopy identified vitreoretinal adhesions in only 11 eyes (8%). Two distinct vitreoretinal adhesion patterns were identified with OCT, each associated with partial separation of the posterior hyaloid face: focal (n = 25) and multifocal (n = 14). CONCLUSIONS: Optical coherence tomography is more sensitive than biomicroscopy in identifying vitreoretinal adhesions associated with macular disease.

Silicone oil tamponade to seal macular holes without position restrictions.

OBJECTIVE: The authors performed a study to determine the effectiveness and safety of silicone oil as a substitute for gas to fill the vitreous cavity to treat macular holes. DESIGN: Multicenter, nonrandomized, interventional trial. PARTICIPANTS: Thirty-seven consecutive patients chose vitrectomy with silicone tamponade instead of gas to treat 40 eyes with stage-2 to stage-4 idiopathic age-related macular holes. Stage-2 holes constituted 40% of the holes, and stage-3 and stage-4 holes made up 60%. INTERVENTION: All eyes were treated with vitrectomy, manual detachment of the posterior vitreous face (not done for stage-4 holes), autologous serum instillation, and silicone fill of the vitreous cavity. After insertion of the oil, the patients resumed normal activity with no restriction of head or eye position except to avoid faceup position. The oil was removed after approximately 6 weeks. MAIN OUTCOME MEASURES: The authors considered the seal of the macular hole and the preoperative and postoperative logarithm of the minimum angle of resolution (logMAR) visions the most significant measures for comparison to other studies. RESULTS: Eighty percent of all holes and 86% of holes not treated previously were sealed with a single silicone tamponade of the vitreous cavity. The logMAR value of visual acuity improved an average of 0.26 (2.6 lines) to 0.61 (20/81) for all eyes and 0.34 (3.4 lines) to 0.52 (20/66) when the macular hole sealed. Completeness of fill of the vitreous cavity with silicone affected seal of the macular hole. Three of eight eyes in which open holes developed after oil removal had less than 90% fill of the vitreous cavity by silicone. Sixty-nine percent of lenses increased opacity one grade or were removed after silicone tamponade. There were no significant adverse effects arising from silicone tamponade. CONCLUSIONS: Silicone oil tamponade of macular holes is effective and safe. Silicone may be optimal for the treatment of macular holes in persons who must travel, who cannot maintain facedown positioning, or who have monocular vision. The most important factor in the successful closure of the macular hole was the completeness of fill of the vitreous cavity with silicone oil.

Peripheral retinal cryotherapy for postvitrectomy diabetic vitreous hemorrhage in phakic eyes.

PURPOSE: To review the anatomic and visual outcomes of a consecutive series of phakic patients with postoperative diabetic vitreous hemorrhage (PDVH) who underwent revision vitrectomy with peripheral retinal cryotherapy. METHODS: We performed a retrospective chart review of consecutive phakic patients who underwent revision vitrectomy for PDVH who also received peripheral retinal cryotherapy. Final corrected visual acuities after revision vitrectomy with peripheral retinal cryotherapy were compared to corrected visual acuities before and at the time of PDVH. Anatomic outcomes such as retinal attachment, vitreous hemorrhage, iris neovascularization, lens opacity, and anterior hyaloidal neovascularization were considered. RESULTS: Nineteen (86%) of 22 eyes (21 patients) that underwent revision of vitrectomy and transscleral peripheral retinal cryotherapy for PDVH also received supplementary endolaser photocoagulation in the posterior pole. In 16 eyes (73%), no further vitreous hemorrhaging occurred after this procedure. In six eyes (27%), vitreous hemorrhage recurred after revision of vitrectomy and peripheral retinal cryotherapy but cleared spontaneously in three of these eyes. Of the three eyes with nonclearing recurrent vitreous hemorrhage after revision of vitrectomy and peripheral retinal cryotherapy, the cause for the vitreous hemorrhage was known for two: severe, progressive anterior hyaloidal neovascularization. With a mean follow-up +/- SD of 6.8 +/- 5.1 months (range, 0.5 to 19.5 months), final corrected visual acuity after revision of vitrectomy and peripheral retinal cryotherapy for PDVH improved over preoperative visual acuity (at which time vitreous hemorrhage was present) in 18 eyes (82%) because of removal of vitreous hemorrhage from the visual axis. However, final visual acuity reached or exceeded pre-PDVH visual acuity in only five of the 15 eyes for which pre-PDVH visual acuity was known. CONCLUSION: For phakic eyes with nonclearing PDVH, peripheral retinal cryotherapy (often augmented, when possible, by additional posterior pole endolaser photocoagulation) may be used to supplement previous retinal ablative therapy during revision of vitrectomy. This procedure leads to anatomic stabilization and visual improvement in the majority of eyes. Transscleral peripheral retinal cryotherapy is often feasible in situations (such as media opacity) that preclude use of peripheral retinal endolaser or indirect laser photocoagulation.

Vitrectomy with silicone oil or long-acting gas in eyes with severe proliferative vitreoretinopathy: results of additional and long-term follow-up. Silicone Study report 11.

BACKGROUND: The Silicone Study evaluated the outcomes of vitreoretinal surgery for retinal detachment with proliferative vitreoretinopathy (PVR). OBJECTIVE: To evaluate short-term (up to 36 months) outcomes in eyes randomized to silicone oil or perfluoropropane gas and long-term (up to 72 months) outcomes in eyes with attached maculas at 36 months. DESIGN: Prospective, randomized, multicentered surgical trial. SETTING: Community- and university-based vitreoretinal practices. PATIENTS: Two-hundred sixty-five eyes with PVR randomized to perfluoropropane gas and silicone oil with follow-up through 3 years (cohort 1) and 249 eyes with attached maculas at 36 months (121 eyes randomized to long-acting gas [either sulfur hexafluoride or perfluoropropane] and 128 eyes randomized to silicone oil) with follow-up up to 6 years (cohort 2). Both cohorts consisted of eyes that had and had not undergone vitrectomy for PVR (groups 1 and 2, respectively) before randomization. Of the 265 eyes in cohort 1, 24-month follow-up data were available for 218 eyes (82%) and 36-month follow-up data were available for 196 eyes (74%). Of 208 eyes in cohort 2, 48-month follow-up data were available for 146 eyes (70%), 60-month follow-up data for 119 eyes (57%), and 72-month follow-up data for 73 eyes (35%). INTERVENTIONS: Vitrectomy surgery for PVR with a long-acting gas or silicone oil as the intraocular tamponade. MAIN OUTCOME MEASURES: Changes in visual acuity, recurrent retinal detachment, and incidence of complications. RESULTS: In group 1 of cohort 1, compared with oil-treated eyes, gas-treated eyes had a higher rate of complete retinal reattachment from 18 to 36 months (P < .05). No other differences were found. In group 2 of cohort 1, no notable differences were found between treatment arms. In cohort 2, during 6 years of follow-up, attachment of the macula was maintained for all eyes. No notable differences in the rates of complete retinal attachment, visual acuity of 5/200 or better, or glaucoma were found between treatment groups. In contrast, gas-treated eyes had more hypotony (P < .001). Silicone oil-treated eyes that underwent subsequent surgery were more likely to have the oil retained (P = .02). Compared with oil-retained eyes, oil-removed eyes had higher rates of complete posterior attachment (P = .01) and of a visual acuity of 5/200 or better (P < .001) and less keratopathy (P < .05). Compared with oil-removed eyes, gas-treated eyes had a worse visual acuity outcome (P < .05) and more hypotony (P < .01). CONCLUSION: The Silicone Study showed that silicone oil and perfluoropropane gas were equal in most respects for the management of retinal detachments with PVR. Success in the first surgery for PVR is paramount for obtaining better visual results. Overall, surgery for PVR had a high likelihood of retinal reattachment, and if anatomically and visually successful at 3 years, there is an excellent chance that the results will be maintained over the long-term.

Subretinal hemorrhages in proliferative diabetic retinopathy.

PURPOSE: To describe the clinical features of patients with advanced proliferative diabetic retinopathy who underwent vitrectomy and were found to have subretinal hemorrhages. METHODS: The authors conducted a retrospective study of 49 patients with complications of proliferative diabetic retinopathy requiring pars plana vitrectomy and demonstrating the presence of subretinal hemorrhage. Preoperative, intraoperative, and postoperative clinical characteristics were evaluated. Patients were observed for a minimum of 6 months. RESULTS: The location, size, and clearance of subretinal hemorrhages revealed wide variation. Forty-two patients had focal subretinal hemorrhages, and 14 patients within this group had submacular hemorrhages. A retinal break was observed in 15 patients (31%). Only one patient required drainage of the subretinal hemorrhage to achieve retinal reattachment. Vitreous surgery resulted in 59% of patients achieving a visual acuity > or = 5/200. Seventy-nine percent had stable or improved vision, whereas 20% had worse vision after surgery. CONCLUSION: Subretinal hemorrhages appear to be an uncommon feature associated with long-term, advanced proliferative diabetic retinopathy and portend a guarded visual prognosis. These hemorrhages may occur spontaneously in previously untreated eyes and are often unsuspected until observed at the time of vitreous surgery. In general, removal of subretinal hemorrhages was not necessary to achieve macular anatomic attachment, and most patients experienced improved visual function after surgery. Diabetic subretinal hemorrhages may indicate a retinal break, and, therefore, careful ophthalmic inspection should be performed in these patients.

Surgical removal of subfoveal neovascularization in idiopathic juxtafoveolar retinal telangiectasis.

PURPOSE: To investigate the efficacy of the surgical removal of subfoveal choroidal neovascularization in patients with type 2A idiopathic juxtafoveolar retinal telangiectasis. METHODS: Two patients with bilateral acquired idiopathic juxtafoveolar retinal telangiectasis and a subfoveal choroidal neovascular membrane underwent surgical excision of the membrane using standard subretinal surgical techniques. RESULTS: In both cases, surgical removal of the neovascular membrane was complicated by an intimate adherence of the membrane with the overlying neurosensory retina in an area of retinochoroidal anastomosis. A retinal dehiscence occurred in both instances at the time of surgery. Postoperative visual outcome was poor. CONCLUSION: The retinochoroidal anastomoses often visualized in cases of subretinal neovascularization complicating bilateral acquired IJFRT could indicate that there is a fairly marked adherence of the neovascular membrane to the neurosensory retina. Attempts at surgical removal of subretinal membranes in this disease entity with current techniques may be contraindicated.

Visual field loss after macular hole surgery.

BACKGROUND: Vitrectomy has been successfully used for treating idiopathic macular holes. Although macular hole surgery has been successful and is generally regarded as a safe procedure, various complications have been reported. The authors report eight patients with symptomatic peripheral visual field loss occurring after vitrectomy for macular holes. METHODS: Over a 3-year period, vitrectomy with removal of the posterior cortical vitreous and fluid-gas exchange was performed on 50 eyes of 47 patients with idiopathic macular holes. Eight patients reported visual field loss postoperatively, and Goldmann visual fields were obtained. The clinical characteristics and outcomes of the group of patients with visual field loss were compared with the group of patients without visual field loss. RESULTS: Postoperatively, significant peripheral visual field loss was documented in eight patients. The macular holes were anatomically closed in seven eyes (87.5%) of these patients compared with 37 (88.1%) of 42 eyes in the group of patients with no symptomatic visual field loss. The visual field loss was not associated with age, sex, macular hole stage, postoperative intraocular pressure, or history of hypertension or coronary artery disease. The etiology of visual field loss was unclear in six patients. CONCLUSION: Vitrectomy for idiopathic macular holes can result in significant peripheral visual field loss. The etiology of this complication usually is unknown.

Tissue plasminogen activator for preserving inferior peripheral iridectomy patency in eyes with silicone oil.

PURPOSE: An inferior peripheral iridectomy (IPI) was used to prevent forward migration of silicone oil in vitrectomized eyes; however, in approximately one third of eyes, the IPI closed spontaneously. Occlusion of the IPI by fibrin is believed to be an early event in permanent IPI closure by scar tissue. The authors determined whether intraocular tissue plasminogen activator (tPA) would restore and maintain IPI patency in eyes that had early occlusion of the IPI by fibrin. METHODS: Between November 1993 and January 1995, 12 patients who underwent vitrectomy with silicone tamponade and IPI for complicated retinal detachment received an anterior chamber injection of tPA (6.25 or 12.5 microgram) for occlusion of the IPI by fibrin. RESULTS: All 12 patients had lysis of fibrin and maintained a patent IPI at the last follow-up (124+/-95 days). One patient required multiple tPA injections for recurrent fibrin formation. In another patient, a small hyphema developed after the tPA injection, which did not occlude the IPI. When compared with the natural course in a very similar group of patients previously reported, tPA had a statistically significant beneficial effect in the maintenance of IPI patency (P = 0.040). CONCLUSIONS: Intraocular tPA can be safely used to lyse postoperative fibrin occluding the IPI in eyes with silicone oil tamponade. Early lysis of this fibrin maintains IPI patency.

Treatment of migraine headache after ocular surgery with intravenous metoclopramide hydrochloride.

PURPOSE: To alert ophthalmologists that prolonged or severe postoperative periocular pain and nausea may be caused by migraine. METHODS: We examined two patients who had a history of migraine and had severe episodes of prolonged periocular pain and nausea after ocular procedures. Both patients experienced symptoms similar to their previous migraine attacks. In neither was pain alleviated by routine analgesics. RESULTS: Each patient had relief of symptoms within two minutes after intravenous delivery of metoclopramide hydrochloride. CONCLUSIONS: Ophthalmologists should consider the diagnosis of postoperative migraine in similar patients and provide specific therapy such as intravenous metoclopramide hydrochloride.

Clinicopathologic correlation of surgically removed macular hole opercula.

PURPOSE: To determine the ultrastructural characteristic of the operculum associated with macular holes. METHODS: We developed instrumentation and a technique to capture the operculum observed with macular holes. Two opercula were studied by transmission electron microscopy. RESULTS: The two specimens were attached to a layer of native collagen identified as cortical vitreous and were composed primarily of Mueller cells and fibrous astrocytes without adjacent inner limiting membrane. No distinct retinal neuronal tissue was present. CONCLUSIONS: Our findings indicate that proliferation of fibrous astrocytes and Mueller cells occurs with the formation of a macular hole, that this reparative tissue may be dislodged, and it is the reparative tissue that previously has been interpreted as an operculum.

Condensation on the posterior surface of silicone intraocular lenses during fluid-air exchange.

PURPOSE: Posterior chamber foldable silicone intraocular lenses (IOLs) are becoming increasingly prevalent in patients undergoing a pars plana vitrectomy with fluid-air exchange. The authors report an important limitation of foldable silicone IOLs during fluid-air exchanges in pars plana vitrectomies. METHODS: The charts of 18 pseudophakic patients with foldable silicone IOLs who underwent vitrectomy with fluid-air exchange by the authors were reviewed. RESULTS: There was a statistically significant difference in the occurrence of condensation during fluid-air exchange between the group of patients with a capsulotomy versus those that did not have a capsulotomy (P = 0.003). Condensation limiting the view of the retina occurred during fluid-air exchange in 11 of 11 of the patients with foldable silicone lenses and a capsulotomy. Attempts to remove the condensation with a soft-tipped aspiration cannula resulted in limited view of the retina for 1 to 2 minutes in 6 of 11 patients. Use of a thin film of silicone oil restored the view in one patient. In the presence of an intact posterior capsule, condensation did not occur on identical foldable silicone IOLs in seven of seven patients. CONCLUSION: Recognition of the presence of a foldable silicone lens is important when an air-fluid exchange is anticipated. If a capsulotomy is present, the surgeon must be aware that condensation may limit the view of the retina severely during and after surgery. Intraoperatively, the view of the retina usually can be restored in short surgeries by wiping the posterior lens surface with a soft-tipped cannula, and in more complex surgeries by applying a thin film of silicone oil on the posterior surface of the lens.

Primary intraocular lens implantation in the setting of penetrating ocular trauma.

PURPOSE: To evaluate the clinical outcome of patients who underwent lensectomy and intraocular lens (IOL) implantation at the time of primary repair of a penetrating ocular injury. METHODS: A review of 14 patients who sustained cataracts and lens rupture in the setting of a corneal laceration to determine anatomic and visual outcome, in addition to complications related to the primary IOL. RESULTS: The IOL remained anatomically stable in all 14 patients with no complications encountered at implantation or after surgery. Final visual acuity in 9 of the 14 patients was 20/40 or better. Six patients underwent pars plana vitrectomy for removal of an intraocular foreign body. CONCLUSION: Intraocular lens implantation at the time of lensectomy and primary repair of a corneal laceration allows good visual rehabilitation with restoration of binocular function and serves as an alternative to contact lens correction in select patients.

Removal of optic disc stalks during diabetic vitrectomy.

BACKGROUND: The morphologic features and clinical consequences of removing residual optic disc stalks during vitrectomy for complications of diabetic retinopathy have not been described. METHODS: Twenty-four residual optic disc stalks that were surgically removed from eyes with proliferative diabetic retinopathy and dense nonclearing vitreous hemorrhage and/or traction retinal detachment were studied histologically using conventional hematoxylin and eosin staining as well as a modified Glees staining technique. RESULTS: Histologic examination demonstrated that 79% of the specimens consisted of vascularized glial tissue with an infiltrate of mononuclear cells and 21% consisted of glial membranes devoid of vasculature. Axons were identified in 33% of all tissues studied. Intra-operative hemorrhage occurred in three eyes with strongly adherent optic disc stalks and was controlled with transient elevation of the intraocular pressure. The presence of axons in the removed optic disc stalks was not correlated with a decreased final postoperative visual acuity (median time to follow-up 21 months). CONCLUSIONS: Residual optic disc stalks removed during vitrectomy for proliferative diabetic retinopathy frequently contained axons. The presence of axons does not portend an unfavorable postoperative visual outcome.

Inferior peripheral iridectomy in patients receiving silicone oil. Rates of postoperative closure and effect on oil position.

BACKGROUND: Silicone oil tamponade is used in treating retinal detachments, but silicone-associated complications remain frequent. Keratopathy and acute pupillary block glaucoma are related to migration of silicone oil into the anterior chamber. Since 1985, many surgeons have created an inferior peripheral iridectomy (PI) at the time of surgery to prevent forward migration of the oil, but the rate of postoperative closure of the PI and the effect on oil position have not been well defined. METHODS: The charts of 292 patients undergoing silicone oil surgery were reviewed. The status of the PI and the oil position were determined throughout the postoperative period. RESULTS: Postoperative closure of the PI occurred in 40 (33%) of 121 aphakic eyes in the early postoperative period. Forward migration of the oil was highly associated with closure of the PI (32/40, 80%). Conversely, forward oil migration occurred in only 11% (9/81) of eyes with patent PIs. The rate of PI closure was significantly greater for patients with proliferative diabetic retinopathy (21/40, 52%) than for patients with proliferative vitreoretinopathy (11/58, 19%). CONCLUSION: Postoperative closure of the PI occurred in a significant fraction of eyes undergoing silicone oil surgery, was highly correlated with forward oil migration, and occurred most frequently in eyes with proliferative diabetic retinopathy.