Vitreous fluorophotometric evaluation of diabetics.

Vitreous fluorophotometry measurements taken from diabetic patients with different degrees of retinopathy and from normal volunteers were used to evaluate the integrity of the blood-ocular barrier. The contributions of lens and retinal fluorescence to the measured vitreous fluorescence were investigated. Lens autofluorescence was significantly higher for diabetics than for age-matched normals, and in age-matched diabetics the lens autofluorescence increased significantly with the progression of diabetic retinopathy. Natural ocular fluorescence was corrected for by subtracting baseline values from all vitreous measurements. Analysis of the baseline-corrected vitreous fluorescence values showed that both degree of retinopathy and age significantly affected the measured fluorescence. In age-matched groups, vitreous fluorescence values were greater in diabetics than in normals, and these values increased with the progression of retinopathy. Our results suggest that clinical vitreous fluorophotometry may be useful in evaluating the activity and predicting the progression of diabetic retinopathy.

Severe adolescent-onset proliferative diabetic retinopathy: the effect of pituitary ablation.

Proliferative diabetic retinopathy (PDR) is uncommon in patients younger than the age of 20 and has been rarely reported. Since 1969, 14 adolescents with severe PDR have been seen, the youngest of whom was 16 years old and the oldest, 19 years old. The shortest duration of diabetes mellitus prior to diagnosis of PDR was eight years. Ten patients had a positive family history of diabetes. Thirteen patients had suboptimal metabolic control. Ten patients had some degree of azotemia, seven were hypertensive, and six had proteinuria. Ophthalmic findings included advanced neovascular and fibrous proliferation on initial classification, and rapid progression to blindness-which was most frequently secondary to traction retinal detachment. In a small retrospective study, pituitary ablation may have offered greater preservation of vision than that observed in untreated patients.

Electroretinography in the prognosis and classification of central retinal vein occlusion.

Forty-five patients with a central retinal vein occlusion were divided into three groups: those with venous stasis retinopathy (VSR, n = 27), those with hemorrhagic retinopathy (HR, n = 6), and those with undetermined retinopathy (n = 12). The electroretinogram (ERG) was recorded in all cases. The average b/a-wave amplitude ratio of the single white-flash ERG was 1.67 for the VSR group and 0.70 for the HR group. The ERG responses in the group with undetermined retinopathy helped to assess the degree of retinal ischemia and to further categorize the disorder as either VSR or HR. The b/a amplitude ratio reflected the degree of retinal ischemia and had prognostic value in predicting in which cases neovascular glaucoma may develop. The average b/a ratio in the six cases in which neovascular glaucoma developed was 0.84. This complication did not develop in any patient with a b/a ratio greater than 1. Four patients with low b/a ratios (average, 0.73) were treated with panretinal photocoagulation; neovascular glaucoma developed in none.

Visual outcome in moderate and severe proliferative diabetic retinopathy.

Four hundred eyes with moderate or severe proliferative diabetic retinopathy, initial good vision, and an average follow-up of 44.3 months were studied. Final visual acuity was 20/40 or better in 33% of these eyes, 20/50 to 5/200 in 32%, and 5/200 or worse in 35%. A poor visual prognosis was correlated with a traction detachment or relatively poor visual acuity at initial examination. No correlation was found between the length of follow-up and final visual prognosis. General guide-lines are available for the management of these patients' conditions.

Conjunctival capillary fragility: a preliminary study.

Conjunctival capillary fragility (CCF) and skin capillary fragility (SCF) were studied by a negative-pressure suction cup method in 25 normal subjects and 38 diabetic patients with diabetic retinopathy. The CCF was significantly higher (P less than .001) in patients with diabetic retinopathy than in normal subjects; there was no significant difference in the SCF.

Vitreoretinal relationship in diabetic retinopathy. A biomicroscopic evaluation.

The vitreoretinal relationships of 312 eyes with diabetic retinopathy were analyzed statistically, based on the results of biomicroscopic observation and photography of the vitreous. Vitreous detachment usually occurs outside the temporal vascular arcades, and the macula subsequently becomes involved in the midstage of the proliferative process. The incidence of no vitreous detachment and complete vitreous detachment are significantly lower in proliferative retinopathy as compared with nonproliferative than in nonproliferative retinopathy. The relatively high incidence of proliferation with no vitreous detachment indicates that vitreous detachment is not the sole triggering factor in the development of proliferative changes. However, partial vitreous detachment was shown, retrospectively, to stimulate a rapid exacerbation of the proliferative process as compared with eyes having no vitreous detachment or complete vitreous detachment.

Unilateral proliferative diabetic retinopathy. I. Initial findings.

The combination of unilateral proliferative diabetic retinopathy (PDR) in one eye and nonproliferative diabetic retinopathy (NPDR) in the fellow eye was observed in 10.1% of patients with PDR. Most patients were between the ages of 50 and 70 years; the majority had adultonset diabetes mellitus. Unilateral aphakia and anisometropia of greater than 1 diopter were both infrequently seen. The incidence of glaucoma was unremarkable. Unilateral elevated-but not necessarily abnormal-intraocular pressure was found in a significantly larger proportion of eyes with NPDR (20%) than with PDR (12%). Most patients had moderate to severe angiopathy or exudation in the eye with NPDR and modest PDR in the fellow eye; however, one third had moderate to severe PDR. In only 2% of the patients was visual acuity less than 20/200 on initial examination.

Unilateral proliferative diabetic retinopathy. II. Clinical course.

One hundred thirty-six patients with proliferative diabetic retinopathy (PDR) in one eye and nonproliferative diabetic retinopathy (NPDR) in the fellow eye on initial examination were followed up for at least three months. Eight percent of the eyes with NPDR were eliminated from further consideration by treatment within the first three months. Proliferative diabetic retinopathy developed in 58% of the remaining eyes with NPDR, usually within two years of the initial examination. Proliferative diabetic retinopathy developed in a significantly greater percentage of diabetics who were younger than 40 years than in diabetics older than 60 years. Poor visual prognosis among eyes that initially had NPDR was associated with advanced angiopathy or exudation on initial examination and also may have been associated with the subsequent development of PDR. Neither the development of PDR nor the final visual acuity in these eyes could be correlated with vascular disease outside the eye, the degree of PDR in the fellow eye, or the presence of higher intraocular pressure in the eye with NPDR on initial examination. Forty-one percent of the eyes with unilateral PDR were eliminated from consideration by prompt treatment. Most remaining eyes with PDR also showed progressive fundus pathologic conditions.

Diabetic traction detachment.

One hundred thirty-six of 124 patients with diabetic traction detachment (TD) were observed for an average of 4.6 years (range, 3.0 to 9.4 years) with no surgical intervention. Visual acuity was maintained or improved in 51 of these eyes; 71 continued to be 20/200 or better. Diabetic TDs remained stable for long periods, those of more severe grade being more stable. At final examination, 60% (81/136) were graded at the same anatomic level (36/136) or an improved level (45/136). Spontaneous reattachment occurred in 20% (27/136); 78% (21/27) of these eyes had small detachments (TD1). The status of the vitreous and the vitreoretinal adhesion determined both the degree of detachment and the incidence of spontaneous reattachment.

Clinical application of the laser Doppler technique for retinal blood flow studies.

The newly developed laser Doppler technique was used to measure retinal blood flow characteristics in patients with forms of central retinal venous occlusive disease. The measurements were consistent with the expected reduced retinal blood flow in these disease processes.

Effect of vitreous detachment on vitreous fluorophotometry.

Twenty eyes of 17 normal subjects with or without posterior vitreous detachment (PVD) were examined to investigate the influence of various types of PVD on vitreous fluorophotometric readings. Biomicroscopic examinations of the vitreous body were performed with an El Bayadi - Kajiura preset lens, and the findings were classified according to the extent of vitreous detachment and the position of the posterior hyaloid membrane when the eye was stationary. Equivalent fluorescein concentration profiles along various directions in the vitreous cavity were obtained with vitreous fluorophotometry. The degree of PVD significantly affected the measurements. Close to the retina, fluorescein concentrations were significantly higher when the subhyaloid space was sampled than when the vitreous gel was sampled. Our findings have implications for vitreous fluorophotometric assessment of the permeability of the blood-retinal barrier.

Prognostic value of vitreous findings in diabetic retinopathy.

We examined the vitreous in 163 eyes with diabetic retinopathy using a +58.6-diopter aspherical preset lens and a slitlamp. Sixty-eight eyes had no vitreous detachment, 76 eyes had partial vitreous detachment, and 19 eyes had complete vitreous detachment. This article studies the vitreoretinal relationship to determine its role in the progression of proliferative diabetic retinopathy. We found that partial vitreous detachment with vitreoretinal traction is a major risk factor for progression of proliferative diabetic retinopathy, whether or not photocoagulation is performed. With complete vitreous detachment or with no vitreous detachment, the absence of vitreous traction protects against the progression of proliferative diabetic retinopathy.

Choroidal neovascularization in fellow eyes of patients with advanced senile macular degeneration. Role of laser photocoagulation.

Choroidal neovascularization in fellow eyes of patients with advanced disciform macular scars usually has an unfavorable prognosis. Fifty-two such fellow eyes were treated, using the monochromatic green argon laser. The neovascular membranes were foveal in 24 eyes, juxtafoveal in ten eyes, and perifoveal in 18 eyes. Complete closure of the choroidal new vessels after treatment was seen in 46 eyes. Only one eye in the foveal group and five eyes in the juxtafoveal group had residual new vessels. After an average follow-up period of 16 months, improvement or stabilization of vision was seen in 36 eyes--18 eyes in the foveal group, four in the juxtafoveal group, and 14 in the perifoveal group. In view of the rewarding anatomical and functional results, photocoagulation, using the monochromatic green argon laser, should be considered in these high-risk eyes. Treatment of foveal neovascular membranes seems to be indicated if the visual acuity is 20/70 or worse.

Retinal blood flow alterations during progression of diabetic retinopathy.

Alterations in retinal blood flow during the progression of diabetic retinopathy were studied using the dye-dilution technique. Mean fluorescein circulation times were measured in retinal arteriovenous segments with a two-point fluorophotometer in 48 diabetic patients and 20 normal controls. Monochromatic fundus photographs were used to determine vessel diameters. Segmental blood flow (SBF) increased with the progression of background diabetic retinopathy. In patients with distinct capillary closure, SBF was significantly higher than normal values.

Prolongation of the retinal mean circulation time in diabetes.

Retinal mean circulation time (MCT) and vascular sizes were measured in 21 normal individuals and 32 individuals with diabetes, and segmental blood flow (SBF) was calculated. The MCT was similar in the normal individuals (4.0 +/- 1.1 s) and the individuals with diabetes (4.2 +/- 1.9 s) when seven individuals with diabetes with prolonged but not quantifiable MCT were excluded. Including them by nonparametric statistics revealed that MCT was significantly longer in individuals with diabetes with proliferative retinopathy than in normal individuals or in individuals with diabetes with nonproliferative retinopathy. The prolonged MCT correlated significantly with advanced retinopathy as judged by leakage, neovascularization, and the need for photocoagulation therapy. Reduced SBF may account for the prolonged MCT, since the increase in vascular sizes observed failed to do so. However, pathologic vascular changes may alter the relation between SBF and MCT. Irrespective of implications about SBF, prolonged MCT, which indicates marked circulatory disturbance, represents an important new observation in diabetic retinopathy.

Closed vitreous surgery. XVII. Results and complications of pars plana vitrectomy.

Two hundred consecutive closed vitrectomies through the pars plana were observed for at least five years after operation to determine the results and analyze the complications. Vitrectomy was performed to remove vitreous opacities in 56.5% of the eyes (group 1), as a preliminary procedure in the course of retinal reattachment in 42% (group 2), and to reconstruct the anterior segment in 1.5% (group 3). Of the group 1 eyes for which adequate follow-up data were available, visual acuity improved notably in 64.2% showed no change in 11.3%, and deteriorated in 24.5%. The respective percentages for the other groups were as follows: 23.3%, 19.2%, and 57.5% for group 2; and 0%, +66.7%, and +33.3% for group 3. The most common complication during operation was bleeding in the vitreous, especially in diabetic patients; retinal break, lens injury, and vitreous-base avulsion followed in frequency. Postoperative bleeding occurred in 23% of eyes but usually resolved spontaneously and required no further surgery. There was postoperative glaucoma in 20% of the eyes. Corneal decompensation (15% of all cases) and rubeosis iridis (also 15%) had a propensity to occur in diabetic patients. Multiple procedures seemed to predispose eyes undergoing vitrectomy to rubeosis. Fibrous ingrowth into the vitreous through the sclerotomy was seen in five eyes and was associated with retinal detachment in one.

Diabetic retinopathy. Pathogenesis and the role of retina-derived growth factor in angiogenesis.

Diabetic retinopathy results from a combination of systemic and ocular abnormalities. Vasodilation, basement membrane pathology, microaneurysms, abnormal blood flow and tissue oxygenation, connective tissue abnormalities, and retinal ischemia are all components of early diabetic retinopathy. The pathogenesis of neovascularization is discussed with respect to the effects of vasodilation, vascular leakage, vitreous changes, and retinal ischemia. The evidence supporting Michaelson's hypothesis that a chemical messenger from the retina provides the stimulus for neovascularization is cited. The sequence of events involved in angiogenesis are cellular and basement membrane changes, endothelial cell migration, endothelial cell proliferation, and vessel formation. The experimental evidence in support of a role for retina-derived growth factor as a mediator of these cellular events is reviewed.

Treatment of rhegmatogenous retinal detachment secondary to proliferative diabetic retinopathy.

Fifty eyes with rhegmatogenous retinal detachment associated with proliferative diabetic retinopathy were treated surgically. Follow-up examination was from six months to 14 years with an average of 33 months. Successful reattachment of the retina was achieved in 74% of the cases, and visual acuity was preserved or improved in 60%.

Subretinal hemorrhage in atrophic age-related macular degeneration.

In eight eyes of eight patients we retrospectively studied the outcome of subretinal hemorrhage occurring in areas of atrophy of retinal pigment epithelium and choriocapillaris secondary to age-related macular degeneration. These patients were followed up for one to 20 months after the initial appearance of the hemorrhage. No subretinal new vessels were associated with these hemorrhages, which resolved over one to 15 months. Our findings indicated that hemorrhages occurring within areas of atrophy are not necessarily associated with subretinal new vessels, and that this type of hemorrhage has a good prognosis for resolution.

Glaucoma occurring after closed vitrectomy.

Six of 20 eyes developed postoperative glaucoma within two to ten days after closed vitrectomy for vitreous hemorrhage. Intraocular pressure was greater than 40mm Hg in all six eyes, and three developed pressure greater than 60 mm Hg. Intraocular pressure in four eyes was controlled with medical antiglaucoma therapy and two eyes required anterior chamber irrigation. Six months postoperatively three of the eyes had normal pressures, one was hypotonous, and two developed increased intraocular pressure secondary to angle neovascularization. Three of the 14 eyes that did not develop glaucoma developed a cellular accumulation in the anterior chamber. The glaucoma was caused mainly by obstruction of the trabecular meshwork by degenerated red blood cells known as ghost cells. The cells may be identified by phase-contrast examination of anterior chamber aspirates. Glaucoma can be prevented through irrigation of the vitreous cavity at the time of vitrectomy ensuring that no cells and debris are left behind to migrate into the anterior chamber and obstruct the trabecular meshwork. This type of glaucoma is caused mainly by ghost cells, whereas hemolytic glaucoma is caused mainly by macrophages and red blood cell debris.