The role of inner wall retinectomy in the management of juvenile retinoschisis

PURPOSE: The purpose of this paper is to describe the technique and application of relief of vitreous traction and inner wall retinectomy in the management of juvenile retinoschisis (JRS). In addition, during the course of this study a previously undescribed form of tractional retinal detachment associated with retinal schisis was observed. METHODS: Six eyes of four children with visual field and/or central vision loss underwent vitrectomy (in five of the six eyes the lenses were preserved), inner wall retinectomy and photocoagulation for rhegmatogenous/schisis retinal detachment, tractional retinal detachment and reduced central vision secondary to intraschisis hemorrhage overhanging the macula. RESULTS: The children were followed up for 1 to 4 years. All eyes showed anatomic reattachment. Three of the four eyes that could be tested for vision showed improved visual function postoperatively. One eye showed marked enlargement of visual field and central visual acuity improvement from 20/200 preoperatively to 20/50 postoperatively. CONCLUSION: Inner wall retinectomy can be a useful ajunct in the management of the retinal complication of JRS. Appropriate case selection of eyes with associated central traction retinal detachment can result in improved visual field and central visual acuity. The success of this technique suggests that the mechanical and/or pharmacological relief of vitreous traction may be able to alter the clinical course of JRS.     

In vitro evaluation of the long-body On-X bileaflet heart valve

AIM: To determine the staining pattern of vascular endothelial growth factor (VEGF) at different stages of diabetic retinopathy (including post-laser photocoagulation) and to compare staining in excised fibrovascular and fibrocellular (non-diabetic) preretinal membranes. METHODS: Immunohistochemical localisation of VEGF, using antibodies raised against VEGF165 and VEGF121,165,189, was carried out on specimens of normal human retina (n = 15), diabetic retinas ((a) with no overt retinopathy (n = 19), (b) with intraretinal vascular abnormalities but no proliferative retinopathy (n = 6), (c) with active proliferative retinopathy (n = 6), (d) with no residual proliferative retinopathy after photocoagulation therapy (n = 15)), excised diabetic fibrovascular membranes (n = 19), and non-diabetic fibrocellular membranes (n = 7). The degree and pattern of immunostaining was recorded. RESULTS: In general, VEGF was absent from the majority of normal retinas. VEGF staining was apparent in most diabetic tissues but the staining pattern was dependent on both the specificity of the antibody used and the category of tissue. Staining with the VEGF165 antibody was generally confined to endothelial cells adn perivascular regions while the VEGF121,165,189 antibody was also associated with extravascular components of the inner retina. Intensity of immunostaining of diabetic eyes was dependent on the severity of retinopathy being least in diabetics with no overt retinopathy and greatest in retinas with proliferative retinopathy. Interestingly, the intensity of immunostaining in diabetic retinas which had undergone laser surgery for proliferative retinopathy was reduced to basal levels. Moderate to intense immunostaining was observed in all fibrovascular and fibrocellular membranes examined. CONCLUSIONS: This study supports a circumstantial role for VEGF in the pathogenesis of both the preclinical and proliferative stages of diabetic retinopathy.     

The results of vitreous surgery for chronic macular holes

PURPOSE: To evaluate the visual and anatomic results of macular hole surgery in eyes that have had symptoms of a macular hole for 2 years or longer. METHODS: Fifty-one eyes with chronic macular holes (> or = 2 years' duration) were treated in a retrospective analysis of the results of vitrectomy, 16% perfluoropropane gas tamponade, and one of three adjunctive agents (bovine transforming growth factor beta-2, recombinant transforming growth factor beta-2, or autologous platelet extract). Of 51 eyes, 45 (88.2%) were examined 3 months after surgery. Visual acuity of these 45 eyes was measured preoperatively and 3 months postoperatively using the Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity chart. Twenty-eight eyes (62.2%) had no prior vitrectomy and 17 eyes (37.8%) had a prior vitrectomy for the macular hole that failed. RESULTS: The macular holes had a mean duration of 3.7 years and were successfully closed in 32 of 51 total eyes (62.7%) and 32 of 45 eyes (71.1%) that were examined 3 months after surgery. The mean preoperative visual acuity was 20/100 -2 and the mean visual acuity at 3 months was 20/80 for a mean gain of 6.6 ETDRS letters (+ 1.3 lines). Of 45 eyes, 17 (37.8%) were 20/63 or better 3 months after surgery; 21 (46.7%) gained 2 or more ETDRS lines. There was no statistically significant difference in macular hole closure (P = 0.311) or visual acuity change (P = 0.095) in eyes with or without prior vitreous surgery. Eyes with macular holes between 2-2.99 years experienced a somewhat better anatomic and functional result overall than eyes with macular hole from 3-14 years, duration, but the visual acuity change was not statistically significant (P = 0.187). There was substantial variability in visual improvement among eyes with successful closure of the chronic macular hole. CONCLUSIONS: Macular holes of > or = 2 years' duration may be more difficult to close successfully than are more recent macular holes, and the visual improvement appears to be less favorable. Many eyes with chronic macular holes in our study gained substantial visual acuity, so vitreous surgery can be considered in selected eyes with chronic macular holes based on visual needs.     

Ruthenium-106 brachytherapy for peripheral retinal capillary hemangioma

OBJECTIVE: This study aimed to evaluate the efficacy and safety of ruthenium-106 brachytherapy of large peripheral retinal capillary hemangiomas. DESIGN: A retrospective case series. PARTICIPANTS: In 25 eyes of 24 patients, peripheral capillary retinal hemangiomas were treated. INTERVENTION: Brachytherapy using 106-ruthenium/106-rhodium plaques was performed. MAIN OUTCOME MEASURES: Eyes were reviewed for hemangioma regression after brachytherapy, occurrence of retinal detachment, requirement of additional vitreoretinal surgery, final visual outcome, and final retinal status. RESULTS: Preoperative mean visual acuity of all eyes treated was 20/60, mean hemangioma diameter was 3.8 mm, corresponding to approximately 2 disc diameters. In 14 eyes, the retina was attached before surgery, 8 eyes showed an exudative detachment, and 3 eyes showed a traction detachment. Fifteen patients had definite von Hippel-Lindau syndrome. Twenty-three of 25 hemangiomas could be destroyed by single brachytherapy. In 16 eyes, a favorable outcome could be achieved. In nine eyes, outcome was unfavorable, characterized by a severe drop in visual acuity, a persisting exudative retinal detachment, or a recurrent traction detachment. In one eye requiring repeated brachytherapy, irradiation retinopathy occurred. Hemangiomas up to a size of approximately 5.0 mm without preoperative exudative detachment could be treated safely by brachytherapy, whereas a larger hemangioma size or a pre-existing exudative retinal detachment predisposed to an unfavorable outcome. CONCLUSION: Solitary peripheral retinal hemangioma can be ablated effectively by ruthenium-106 brachytherapy. A favorable outcome can be expected if the hemangioma diameter is 5.0 mm or smaller and if there is no preoperative exudative retinal detachment.     

Vitrectomy in Coats' disease

Four eyes of four patients with Coats' disease underwent vitrectomy because of exudative or tractional detachments involving the macula or premacular fibrosis. All cases had gelatinous vitreous and had no complete posterior vitreous detachment. The exudates decreased and the retina reattached after removing vitreous traction and coagulating abnormal vessels with endodiathermy and not removing subretinal fluid in 3 eyes with retinal detachment. In one eye with tractional detachment, retinal breaks were found beneath the proliferative membrane during the initial vitrectomy procedure. This eye needed multiple operations because of recurrent traction by the remaining peripheral vitreous. Exudation into the vitreous and vitreous traction may cause mutual progression in these eyes, and vitrectomy is an effective treatment, although there are difficulties in removing vitreous traction completely.     

Complications of surgery for epiretinal membranes

PURPOSE: Surgery has been successful in removing epiretinal membranes (ERM) from the macula, allowing some improvement in vision in 80-90% of patients; however, complications are relatively frequent. We conducted a retrospective study to evaluate the rate of peri- and postoperative complications and their influence on functional outcome of eyes having been operated on for ERM. MATERIAL AND METHODS: Preoperative findings, intraoperative and postoperative complications as final results of 70 consecutive cases of idiopathic or secondary ERM operated on by the same retina surgeon were analyzed. RESULTS: In all cases the ERMs were successfully removed from the fovea. The mean visual acuity (VA) increased from 0.34 +/- 0.2 to 0.54 +/- 0.31 (P < 0.05) postoperatively. Idiopathic and secondary ERM both showed significant improvement after surgery. Complications included intraoperative hemorrhage and retinal tears and postoperative progressive nuclear sclerosis, retinal tears causing detachments, macular edema and retinal pigmentary epitheliopathy. Final VA was not significantly different from the mean after complications, apart from when retinal detachments involved the macular area. CONCLUSIONS: Performing surgery for ERM is worthwhile in eyes with major decreased VA and in eyes with metamorphopsia but only moderately reduced vision. Postoperative complications are frequent but can usually be managed successfully. Of them, only retinal detachment has a negative effect on the final functional outcome.     

Diabetic retinopathy

Nonproliferative diabetic retinopathy may cause visual loss when associated with macular edema or macular ischemia (secondary to retinal capillary nonperfusion). Proliferative diabetic retinopathy may cause severe visual loss if complicated by vitreous hemorrhage or traction detachment of the macula. Patients with diabetes benefit from collaboration between the internist and ophthalmologist. Tighter control of blood glucose levels and lower blood pressure reduce the risk of progression of diabetic retinopathy. Regular dilated eye examinations and appropriate intervention with laser or vitrectomy surgery help to preserve vision in patients with established macular edema or proliferative diabetic retinopathy.     

Molecular cloning and regional distribution of a human proton receptor subunit with biphasic functional properties

BACKGROUND: At present no satisfying treatment for subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) is available. Visual results after successful surgical removal of subfoveal CNV are disappointing. This has been explained by a primary dysfunction of the retinal pigment epithelium (RPE) in the macular region and the surgical trauma to the RPE in patients with AMD. Therefore, Machemer and Steinhorst developed a technique for macular translocation after surgical removal of subfoveal CNV. We report our first experiences with this technique in patients with subfoveal CNV secondary to AMD. METHODS: Seven patients aged between 71 and 83 years with subfoveal CNV were included in the study. Visual acuity of the fellow eyes was below 20/400. All patients underwent pars plana vitrectomy. Retinal detachment was produced by subretinal infusion of balanced salt solution and a 360 degrees retinotomy at the base of the vitreous was performed. After removal of the CNV, retinal rotation and reattachment, the retina bordering the retinotomy was coagulated with endolaser photocoagulation. Silicone oil was used as temporary tamponade. RESULTS: In all patients the subfoveal CNV was removed and the macula was translocated by a 15 degrees-45 degrees rotation onto functional RPE. The mean duration of follow-up was 11 +/- 3 months. Initial visual acuity ranged from 20/80 to hand movements. Final visual acuity was 20/100 to 20/400. Initially all patients complained of tilted vision. During follow-up the rotation of the image regressed and was well tolerated by all patients. Complications included the development of retinal detachment in three patients after silicone oil removal, development of a macula pucker, and a significant increase of lens opacity in the phakic eyes. CONCLUSION: In our series rapid improvement of visual function was observed in one patient only, even if the macula appeared ophthalmoscopically and angiographically normal. Vitreoretinal complications occurred frequently during follow-up.     

Surgical results of persistent hyperplastic primary vitreous

PURPOSE: To evaluate the surgical success of patients with persistent hyperplastic primary vitreous (PHPV) and to identify preoperative indicators of visual outcome. DESIGN: Noncomparative case series. METHODS: The diagnosis of PHPV was made in 35 eyes of 27 patients from 1982 to 1994. In each case, anterior and/or posterior PHPV findings, preoperative testing, surgical procedures, and visual outcomes were documented. Twenty-nine of 35 eyes were managed surgically. Follow-up ranged from 2 months to 12 years. RESULTS: Of the 35 eyes, 2 (5.7%) had strictly anterior PHPV, 8 (22.9%) had strictly posterior PHPV, and 25 (71.4%) had components of both anterior and posterior disease. Initial lensectomy and vitrectomy was performed in 24 eyes (68.6%). Surgery was withheld in four eyes secondary to severity of disease with an unrecordable visual-evoked potential (VEP). Reoperation rate was 32.3% for membrane reproliferation, glaucoma, vitreous hemorrhage, retinal detachment, or strabismus. Best-corrected final visual acuity ranged from 20/60 to no light perception. Six eyes (17%) maintained Snellen visual acuity despite posterior PHPV with some degree of retinal dysplasia. CONCLUSIONS: Surgical treatment of PHPV can result in functional visual outcome despite posterior segment involvement. The degree of ocular malformation, however, will ultimately limit the amount of visual improvement. Preoperative testing, including VEP, may aid in determining surgical candidates.     

Intraretinal foreign bodies

PURPOSE: To present our experience with the removal of intraretinal foreign bodies. MATERIAL AND METHODS: 9 intraretinal foreign bodies were removed by pars plana vitrectomy. Laser photocoagulation of the retina surrounding the foreign body was performed either before surgery or intraoperatively (endolaser). Pars plana vitrectomy with foreign body removal through the sclerotomy site with endomagnet and/or forceps was performed. In some cases fluid-gas exchange was done. RESULTS: The average follow-up period was 6.2 months. Seven of nine foreign bodies were magnetic and two were nonmagnetic. Five of seven magnetic foreign bodies had negative magnetic traction as the first surgical procedure. In these 9 eyes, final visual acuity was below 1/50 in 2 eyes and over 5/50 in 7 eyes. CONCLUSION: Pars plana vitrectomy should be the method of choice in removal of intraretinal foreign bodies.     

A case of acute pulmonary edema and bulbar paralysis after local epinephrine infiltration

A cataract developed in a 23-year-old man 4 months after a vitrectomy to repair a traumatic retinal detachment. An uneventful phacoemulsification was performed, using antibiotic-fortified infusion solution. Afterward, a large area of atrophic retina, consistent with gentamicin toxicity, was observed in the macula. The patient remains stable with 20/200 best-corrected acuity. The authors suggest that because the vitreous had been removed, gentamicin was able to settle over the macula during the entire cataract procedure. Therefore, gentamicin should be used intracamerally with caution, especially in eyes in which vitrectomy has been performed.     

Ultrasound biomicroscopic findings of anterior hyaloidal fibrovascular proliferation

We performed ultrasound biomicroscopy (UBM) on 5 eyes with anterior hyaloidal fibrovascular proliferation (AHFVP), which had developed after vitrectomy for proliferative diabetic retinopathy. AHFVP was observed as a thick membrane or a mass image which extended from the vitreous base to the pars plicata, and was apparently differentiated from the anterior vitreous membrane and cilliary body. UBM showed proliferative stalks extending from sclerotomy sites toward the anterior vitreous membrane. These UBM images indicated that AHFVP originated from sclerotomy sites. UBM also enabled us to detect traction detachment of the peripheral retina associated with AHFVP, which could not be observed by conventional B-mode echography. Thus UBM is useful in establishing a diagnosis of AHFVP, and this technique is valuable to determine the indication and the timing of surgical treatment for AHFVP.     

Vitrectomy for retained lens fragments after phacoemulsification

PURPOSE: Posterior lens fragments after phacoemulsification can be a serious complication of cataract surgery. This study is designed to evaluate the clinical features of eyes after pars plana vitrectomy has been performed to remove posteriorly dislocated lens fragments after phacoemulsification. METHODS: The authors performed a retrospective chart review of 126 consecutive eyes of 126 patients with dislocated lens fragments after phacoemulsification, managed with pars plana vitrectomy at Associated Retinal Consultants of Michigan. These eyes were operated on from January 1986 through January 1996. RESULTS: The relation of the intervals between cataract surgery and vitrectomy to various postoperative clinical parameters was studied. Clinical features at presentation included elevated intraocular pressure (IOP over 25 mmHg) in 52.4% of the eyes, uveitis in 69.6%, and corneal edema in 50.8%. Initial visual acuity was 20/400 or worse in 73.8% of the eyes. The mean preoperative visual acuity was 20/278 (median, 20/400), whereas the mean final visual acuity was 20/40 (median, 20/50) after a mean follow-up of 18.9 months. Retinal detachments were found in 20 eyes: 7 before vitrectomy and 13 during or after it. After surgery, 44% of eyes achieved a final visual acuity of 20/40 or better and 90% were 20/400 or better. The distribution of best-corrected final visual acuities among the eyes showed statistically significant differences based on the type of intraocular lens (IOL) used, with posterior chamber IOL greater than anterior chamber IOL, and anterior chamber IOL greater than aphakia. Reasons for a poor visual outcome included persistent corneal edema (four eyes), retinal detachment (two eyes), central retinal vein occlusion (two eyes), age-related macular degeneration (two eyes) glaucoma (one year), and endophthalmitis (one eye). CONCLUSIONS: There were no statistically significant differences between early (< 7 days) and delayed (8 days or more) vitrectomy when increased IOP, corneal edema, choroidal effusions, cystoid macular edema, and visual acuity were analyzed. The use of vitrectomy to remove posteriorly dislocated lens fragments has been shown to be an effective treatment method that significantly reduces the inflammatory response and hastens visual recovery.     

Results of surgery of vitreomacular traction syndromes

PURPOSE: The vitreomacular traction syndrome is a rare entity in which partial posterior vitreous detachment is combined with persistent macular adherence, thus causing macular traction. In most cases, an epimacular membrane is associated with this vitreomacular traction. We evaluate here the results of vitreous surgery for this syndrome. METHODS: We reviewed 18 consecutive eyes that had undergone vitrectomy and posterior epiretinal membrane stripping, to define the visual results and complications of surgery for the vitreomacular traction syndrome. Minimum follow-up was 3 months. RESULTS: Patients' average age was 63.5 years. All had evidence of cystic macular changes on biomicroscopic examination. Sixteen patients had an epiretinal membrane, and two, a full-thickness macular hole. Cystoid macular edema was present in 7 eyes on fluorescein angiography. The release of vitreomacular traction improved vision in 72% of eyes, with six patients obtaining 20/40 visual acuity or better. Complications of surgery included progression of nuclear sclerosis, and epiretinal membrane formation. CONCLUSION: Vitrectomy for vitreomacular traction syndrome may improve visual acuity, but the visual prognosis remains poor.     

Autologous platelet concentrate as an adjunct in macular hole healing: a pilot study

PURPOSE: A pilot study was undertaken to assess the efficacy of autologous platelets in macular hole healing. PATIENTS AND METHODS: Eight eyes of eight patients with stage 3 or 4 macular holes, two of which had failed to heal after previous vitrectomy and gas tamponade, were included. The procedure consisted of pars plana vitrectomy with removal of posterior cortical vitreous, stripping of associated epimacular membranes, 15% perfluoroethane-air tamponade, and instillation of autologous platelet concentrate onto the posterior pole. Strict postoperative facedown positioning was observed for 12 days. Postoperative evaluation included visual acuity measurement, biomicroscopic macular appearance and scanning laser ophthalmoscope examination. The follow-up period ranged from 3 to 13 months (mean, 7 months). RESULTS: Of eight eyes, flattening of the surrounding retina and closure of the hole were achieved in seven (87.5%). Visual acuity improved two lines or more in four eyes (50%) Four eyes (50%) reached a postoperative visual acuity of 20/50 or more. Increased nuclear sclerosis was observed in six eyes (75%), and retinal detachment occurred in two eyes (25%). CONCLUSIONS: Autologous platelet concentrate administered peroperatively in full-thickness macular holes seems to be a safe and effective adjunct to vitrectomy with removal of posterior hyaloid and gas tamponade. A larger multicenter randomized prospective study is underway to verify these encouraging results before advocating the use of autologous platelets in macular hole surgery.     

Timing of lymphocyte activation in neonates infected with human immunodeficiency virus

PURPOSE: To report the results of vitreoretinal surgery for the management of complications associated with congenital retinoschisis in children. METHODS: We conducted a review of consecutive children with complications of congenital retinoschisis treated with advanced vitreoretinal techniques. Nine eyes of seven patients with congenital retinoschisis had vitreoretinal surgery for one of the following complications of congenital retinoschisis: hemorrhage within a large schisis cavity with a dense vitreous hemorrhage; rapid progression of schisis threatening the macula; obscuration of the macula by the overhanging inner wall of a schisis cavity; a combined schisistraction retinal detachment; or a combined schisis-rhegmatogenous retinal detachment. Vitreoretinal surgery consisted of vitrectomy, inner schisis wall retinectomy, fluid-gas exchange, endolaser treatment, and perfluoropropane gas injection. After vitreoretinal surgery, patients were followed up for a mean of 26 months (range, 9 to 67 months). Retinal reattachment, visual acuity, and visual fields were used as outcome measures. RESULTS: Eight of nine eyes had successful retinal reattachment. Six eyes postoperatively had improved visual acuity or visual field, or both. One eye had stabilization of visual acuity, and two eyes had a decrease in visual acuity. CONCLUSION: In children with complications of congenital retinoschisis, vitreoretinal surgery with excision of the inner wall of the peripheral schisis cavity may be effective in achieving retinal reattachment, thereby improving visual acuity or visual field size.     

Longer-term visual outcome of eyes with retinopathy of prematurity treated with cryotherapy or diode laser

AIMS: Visual outcome of 66 eyes in 37 patients who had undergone treatment with either cryotherapy or diode laser for threshold retinopathy of prematurity was assessed. METHODS: 17 patients, representing 30 eyes treated with cryotherapy, were examined at between 56 and 98 months corrected age (median 68 months). 20 patients representing 36 eyes treated with diode laser, were examined at between 30 and 66 months corrected age (median 51 months). Structural outcome was categorised as: optimal--flat posterior pole; suboptimal--macular ectopia, optic nerve hypoplasia, retinal fold involving the macula, and retinal detachment involving the macula. RESULTS: Optimal structural outcome was, in the absence of amblyopia, associated with optimal visual acuity (of 6/12 or better) in all cases, with most eyes achieving a visual acuity of 6/9 or 6/6. Suboptimal structural outcome was invariably associated with suboptimal visual acuity. Amblyopia was present in eight out of 20 cryotherapy treated eyes and in five out of 26 laser treated eyes with an optimal structural outcome. Refractive errors were significantly less in laser treated eyes as was the incidence of anisometropic amblyopia. CONCLUSION: Eyes treated with either cryotherapy or diode laser for threshold retinopathy of prematurity with optimal structural outcome are associated with development of optimal visual acuity--that is, 6/12 or better. Treatment with either cryotherapy or laser does not in itself reduce the visual potential of these eyes.     

Topography of diabetic macular edema with optical coherence tomography

OBJECTIVE: This study aimed to develop a protocol to screen and monitor patients with diabetic macular thickening using optical coherence tomography (OCT), a technique for high-resolution cross-sectional imaging of the retina. DESIGN: A cross-sectional pilot study was conducted. PARTICIPANTS: A total of 182 eyes of 107 patients with diabetic retinopathy, 55 eyes from 31 patients with diabetes but no ophthalmoscopic evidence of retinopathy, and 73 eyes from 41 healthy volunteers were studied. INTERVENTION: Six optical coherence tomograms were obtained in a radial spoke pattern centered on the fovea. Retinal thickness was computed automatically from each tomogram at a total of 600 locations throughout the macula. Macular thickness was displayed geographically as a false-color topographic map and was reported numerically as averages in each of nine regions. MAIN OUTCOME MEASURES: Correlation of OCT with slit-lamp biomicroscopy, fluorescein angiography, and visual acuity was measured. RESULTS: Optical coherence tomography was able to quantify the development and resolution of both foveal and extrafoveal macular thickening. The mean +/- standard deviation foveal thickness was 174 +/- 18 microns in normal eyes, 179 +/- 17 microns in diabetic eyes without retinopathy, and 256 +/- 114 microns in eyes with nonproliferative diabetic retinopathy. Foveal thickness was highly correlated among left and right eyes of normal eyes (mean +/- standard deviation difference of 6 +/- 9 microns). Foveal thickness measured by OCT correlated with visual acuity (r2 = 0.79). A single diabetic eye with no slit-lamp evidence of retinopathy showed abnormal foveal thickening on OCT. CONCLUSIONS: Optical coherence tomography was a useful technique for quantifying macular thickness in patients with diabetic macular edema. The topographic mapping protocol provided geographic information on macular thickness that was intuitive and objective.     

The role of vitrectomy for diabetic retinopathy

BACKGROUND: Diabetic retinopathy is an important cause of severe vision loss. The risk of vision loss from diabetic retinopathy is substantially reduced by intensive control of diabetes and appropriate laser surgery for proliferative diabetic retinopathy and diabetic macular edema. METHODS: The Diabetic Retinopathy Vitrectomy Study (DRVS) helped identify the indications and most propitious time for performing diabetic vitrectomy for nonresolving vitreous hemorrhage. The DRVS also highlighted the risks and potential complications of vitrectomy surgery. RESULTS: Diabetic persons with severe vision loss from severe proliferative diabetic retinopathy are candidates for vitrectomy after vitreous hemorrhage and severe fibrous changes in the retina. CONCLUSION: In cases in which vision loss occurs, pars plana vitrectomy frequently can restore useful vision, and reduce the risk of vision loss from traction retinal detachment.     

Macular edema caused by contraction of the posterior hyaloid in diabetic retinopathy. Surgical treatment of a series of 22 cases

We have observed some patients with diabetic macular edema who did not respond to grid laser treatment and who improved with spontaneous posterior vitreous detachment or vitrectomy. These cases have a taut and glistening vitreo-macular interface. Three such cases are presented in detail. Pars plana vitrectomy with separation of the posterior hyaloid was performed in 22 cases. All of them had proliferative diabetic retinopathy, previously treated by panretinal photocoagulation. Fourteen cases had an ineffective macular grid laser treatment. Postoperative visual acuity was improved in 19 eyes and was unchanged in three eyes. The macular edema disappeared in 12 eyes and decreased in 10. Complications included a vitreous hemorrhage in 6 eyes, a paramacular tear in 1 eye, a reghmatogenous retinal detachment in 1 eye and cataract formation in 2 eyes. Vitreous surgery can improve the visual prognosis in cases of diabetic macular edema associated with a pathological vitreo-macular interface.