Ronald G. Michels

The Classification of Retinal Detachment with Proliferative Vitreoretinopathy

The term proliferative vitreoretinopathy (PVR) is proposed as a designation for the clinical condition previously known variously as massive vitreous retraction, massive preretinal retraction, or massive periretinal proliferation. This is an abnormality in which rhegmatogenous retinal detachment is complicated by proliferation of membranes on both surfaces of the detached retina and on the posterior surface of the detached vitreous gel. The new classification subdivides PVR into four stages: A, minimal; B, moderate; C, marked; and D, massive. The extent of the fixed retinal folds is subdivided to indicate the number of involved quadrants. The degree of retinal shrinkage into a funnel-like configuration is subdivided into three grades.

Correlation of fibrosis and transforming growth factor-beta type 2 levels in the eye.

Approximately 1 out of every 10 eyes undergoing surgery for retinal detachment develops excessive intraocular fibrosis that can lead to traction retinal detachment and ultimate blindness. This disease process has been termed proliferative vitreoretinopathy (PVR). The ability to monitor and grade this fibrotic response accurately within the eye as well as the ability to aspirate vitreous cavity fluid bathing the fibrotic tissue makes this an ideal setting in which to investigate the development of fibrosis. Although laboratory studies have recently shown that transforming growth factor-beta (TGF-beta) can enhance fibrosis, little clinical evidence is yet available correlating the level of this or other growth factors with the degree of fibrosis in a clinical setting. We have found that vitreous aspirates from eyes with intraocular fibrosis associated with PVR have more than three times the amount of TGF-beta (1,200 +/- 300 pM [SEM]) found in eyes with uncomplicated retinal detachments without intraocular fibrosis (360 +/- 91 pM [SEM]). Using an in vitro assay, 84-100% of the TGF-beta activity could be blocked with specific antibodies against TGF-beta 2, whereas only 10-21% could be blocked by specific antibodies against TGF-beta 1. TGF-beta 1 was used in an animal model of traction retinal detachment. Since beta 1 and beta 2 have essentially identical biologic effects and only human beta 1 was available in quantities required, beta 1 was chosen for these in vivo studies. The injection of TGF-beta1 plus fibronectin (FN) but not TGF-beta1 alone into the vitreous cavity of rabbits resulted in the increased formation of intraocular fibrosis and traction retinal detachments as compared to control eyes. In previous studies, intravitreal FN levels were also found to be elevated in eyes with intraocular fibrosis.

Penetrating Ocular Injuries: Types of Injuries and Visual Results

The authors studied the hospital records of 453 patients who underwent primary surgical repair of penetrating ocular injuries at the Wilmer Institute from January 1970 through December 1981. The injury was due to blunt force in 22%, a sharp laceration in 37%, and a missile in 41%. The following factors correlated with the final visual outcome: (1) initial visual acuity after the injury, (2) presence of an afferent pupillary defect, (3) type of injury, (4) location and extent of the penetrating wound, (5) type of lens damage, (6) presence and severity of vitreous hemorrhage, and (7) type of intraocular foreign body. This study emphasizes that the prognosis after a penetrating injury is strongly influenced by the nature of the injury and the extent of initial damage.

Clinical Features, Laboratory Investigations, and Survival in Ocular Reticulum Cell Sarcoma

The authors report 32 cases of histologically proven ocular reticulum cell sarcoma (RCS). Follow-up data are available for all patients. Twenty-six patients (81%) have died and the mean survival time was 20 months from the time of diagnosis of RCS. Diagnosis of ocular involvement was made by vitreous biopsy in 56% of cases, enucleation in 13%, and postmortem examination in 31%. The mean age at the time of diagnosis was 60 years. Central nervous system (CNS) involvement was present in 56% of patients, visceral involvement in 16%, and both CNS and visceral involvement in 6%. Isolated ocular disease occurred in 22% of patients. Results of head computed tomography (CT) and cerebrospinal fluid examination more often disclosed evidence of RCS than did body CT or nuclear medicine scans. Responses to treatment were variable, but prognosis for survival is poor.

Idiopathic Epiretinal Membranes: Ultrastructural Characteristics and Clinicopathologic Correlation+

Current theories of idiopathic epiretinal membrane (ERM) pathogenesis, based mainly on clinical and autopsy studies, emphasize a glial tissue origin. The clinical and ultrastructural features of 101 cases of idiopathic ERMs removed from the macular area during vitrectomy were studied. The predominant cell type was retinal pigment epithelium (RPE) in 51 cases, fibrous astrocytes in 29 cases, fibrocytes in 14 cases, and myofibroblasts in 7 cases. Features of myofibroblastic differentiation were present in 64 cases. Myofibrocytes were more common in younger patients with shorter duration of symptoms. Fibrous astrocytes were more common in females. The high incidence of RPE cells in this series raises new questions regarding the pathogenesis of idiopathic ERMs.

Vitroctomy for Macular Pucker

Abstract Vitreous surgery was used to treat 130 consecutive cases with epiretinal membranes causing macular pucker. The membrane: (1) occurred after otherwise successful retinal reattachment surgery in 78 eyes (60%), (2) was idiopathic in 28 eyes (22%), (3) was associated with other ocular disorders in 20 eyes (15%), and (4) in four eyes may have been developmental. The abnormal tissue was successfully removed in 128 of 130 eyes, and vision improved at least two lines on the Snellen chart in 108 eyes (83%). Postoperative visual acuity was 20/20 in five eyes (4%), 20/25 to 20/40 in 41 eyes (31.5%), 20/50 to 20/100 in 64 eyes (49%), 20/200 in 15 eyes (11.5%), and 20/400 in five eyes (4%). Complications included one case of sterile endophthalmitis and one case of infective endophthalmitis (Staphylococcus epidermidis). Peripheral retinal tears occurred in six eyes (5%). No posterior retinal breaks occurred in this series. Later retinal detachment occurred in eight eyes (6%) requiring further retinal surgery. Progressive postoperative nuclear sclerotic lens changes occurred in 31 (34%) of 90 phakic eyes. Sizable amounts of epiretinal tissue recurred postoperatively in four eyes (3%).

Nuclear sclerosis after vitrectomy for idiopathic epiretinal membranes.

We performed a retrospective analysis of lens changes occurring after vitrectomy for idiopathic epiretinal membranes causing macular pucker on 75 consecutive phakic eyes. Thirty-five eyes (47%) had appearance or progression of nuclear sclerosis. There were no changes in anterior subcapsular cataracts and three eyes (4%) had minimal changes in posterior subcapsular cataracts. Based on univariate analysis, presence of preoperative nuclear sclerosis, length of follow-up period, and surgeon were found to be associated with the occurrence or progression of nuclear sclerosis. Differences between surgeons were largely accounted for by the difference in proportions with preoperative nuclear sclerosis, and differing lengths of follow-up. Kaplan-Meier life table analysis performed on 53 eyes with examination of fellow eyes and longer follow-up showed significantly more nuclear sclerosis in the operated on eye when compared to the fellow eye (log-rank test, P less than .0001).

Vitrectomy for idiopathic epiretinal membranes causing macular pucker.

We used vitreous surgery to remove idiopathic epiretinal membranes from the macular area in 70 consecutive cases. The abnormal tissue was successfully removed in each case. Vision improved postoperatively in 61 eyes (87%), remained unchanged in six eyes (9%), and worsened in three eyes (4%). However, at the time of final examination vision was improved in only 47 eyes (67%), primarily because of the occurrence or progression of nuclear sclerosis, which occurred in 38 of 60 phakic eyes (63%). Four preoperative factors were associated with final visual acuity of 20/60 or better: (1) initial vision of 20/100 or better, (2) shorter preoperative duration of blurred vision, (3) thin epiretinal membrane, and (4) absence of traction retinal detachment.

Complications of Vitreous Surgery for Diabetic Retinopathy: I. Intraoperative Complications

One hundred seventy-nine eyes were analyzed to determine the incidence of intraoperative complications during vitrectomy for proliferative diabetic retinopathy. Inadvertent corneal epithelial defects occurred in 51 eyes (28%). The lens was removed in 42 (25%) of 170 phakic eyes. This was done through a pars plana approach. Accidental mechanical lens damage occurred in one eye, and mild pharmacologic lens damage occurred in two eyes. Some bleeding from fibrovascular tissue occurred in nearly every case, but this was controlled with diathermy except in seven eyes (4%) in which severe bleeding required premature termination of the operation. Latrogenic retinal tears occurred in 36 (20%) of the 179 eyes. Fifteen (34%) of the total of 44 retinal tears were anterior to the equator, and 11 (73%) of the 15 anterior tears were located posterior to the sclerotomy through which the vitrectomy probe was introduced. Twenty-nine (66%) of the 44 retinal tears were posterior to the equator, and 19 of the 29 occurred within 15 degrees radius of the fovea.

Ultrastructural features of progressive idiopathic epiretinal membrane removed by vitreous surgery.

Clinical and electron microscopic studies of an idiopathic epiretinal membrane that was nonvascularized and progressive showed three types of cells: (1) predominant, fibrocyte-like cells; (2) macrophage-like cells; and (3) glial cells. Most of the abundant collagen showed characteristics of normal vitreous fibrils, although thicker collagen fibrils were also present. These ultrastructural findings, when compared with previously reported features of simple and secondary epiretinal membranes, suggest that clinically complicated epiretinal membranes are composed of more than one cell type, whereas simple epiretinal membranes consist only of glial cells. The fibrocyte-like and macrophage-like cells seen in our case were interpreted as being hyalocytes, rather than being derived from glial or retinal pigment epithelial cells. We support this interpretation by the ultrastructural features of the cells, the presence of abundant normal vitreous collagen, the biologic characteristics of hyalocytes as described by other investigators, and the absence of the ultrastructural features of glial or retinal pigment epithelial cells.