A pilot randomized controlled study on the effect of laser photocoagulation of confluent soft macular drusen.

PURPOSE: The authors determined the effect of photocoagulation of drusen on visual acuity and progression to subretinal neovascular membranes (SRNV). METHODS: One of paired eyes was randomized to photocoagulation with other eye to control in 27 patients having symmetrical maculopathy and visual acuities, aged 46 to 81 years (mean, 69.7 years); follow-up 1 to 6 years (mean, 3.2 years). RESULTS: Final visual acuity was improved in treated eye or decreased in control eye in 12 patients, equal in 13 patients, and decreased in treated eye in 2 patients (P < 0.006). Progression to SRNV was less with treatment. CONCLUSION: Laser photocoagulation of confluent soft macular drusen may improve long-term visual prognosis.

Q-switched neodymium: YAG laser surgery of the vitreous.

Fifty-nine eyes underwent vitreous surgery (vitreolysis) with the Q-switched Nd: YAG laser. This was used to cut vitreoretinal bands and membranes in 16 eyes and to clear persistent vitreous opacities in 25 eyes. The use of appropriate specialized contact lenses and modification of the standard slit-lamp delivery system were essential for vitreous YAG laser surgery. Successful results occurred in eyes where the target tissues were located at distances greater than 2 mm from the crystalline lens and the retina. Vision was improved in 18 eyes, unchanged in 40 eyes, and worse in 1. Complications included focal opacities of the crystalline lens in 5 eyes, retinal holes with detachment in 1 eye, and minor retinal hemorrhages in 4. Methods of preventing complications are discussed.

Treatment of proliferative diabetic retinopathy. Long-term results of argon laser photocoagulation.

Panretinal photocoagulation (PRP) is the treatment of choice for proliferative diabetic retinopathy. Indications for treatment are the presence of disc new vessels or the presence of new vessels elsewhere with hemorrhage. Rubeosis iridis and retinal neovascularization undergo involution following panretinal photocoagulation. The long-term visual results are excellent excepting for eyes with diffuse diabetic retinal ischemia. Long-term follow-up and repeat photocoagulation as needed are advised.

Intensive plasmapheresis in the treatment of diabetic retinopathy.

Two insulin-dependent diabetic patients with advanced nonproliferative and early proliferative retinopathy showed regression of diabetic retinopathy after three weeks of intensive plasmapheresis. Because of the sudden unexplained death in one patient, the study was stopped. However, these observations in this pilot study suggest that factors mediated through plasma contribute to the pathogenesis of diabetic microangiopathy.

Mechanisms of proteinuria in diabetic nephropathy. II. A study of the size-selective glomerular filtration barrier.

We evaluated the size-selective properties of the glomerular barrier in 30 patients in whom diabetic nephropathy was associated with urinary IgG losses. Neutral dextrans of graded size were used to characterize glomerular membrane-pore structure. A fractional IgG clearance (relative to freely permeable inulin) smaller or greater than 0.001 was used to distinguish patients with minor (group 1, N = 14) and major (group 2, N = 16) urinary IgG leakage, respectively. Fractional clearances of dextrans (theta D) of smaller size (radii 20-40 A) were similar, but those of larger dextrans (radii 42-60 A) were elevated in group 2 relative to group 1 patients. When plotted on log-normal probability coordinates, the correlation between theta D and radius in healthy subjects is linear, suggesting that glomerular pores form one population with a normal distribution. In diabetic nephropathy with urinary IgG leakage, however, theta D for large molecules was elevated and departed from linearity, suggesting a bimodal pore size distribution within the glomerular membrane. A pore model of solute transport revealed (1) the upper pore mode was highly permeable to large dextrans equivalent in size to IgG and (2) the fraction of glomerular filtrate permeating the large pores was greater in group 2 than in group 1 patients with diabetic nephropathy, 6% versus 3%, respectively. We conclude that urinary IgG leakage in diabetic nephropathy is determined by the development of a subpopulation of enlarged pores. The magnitude of urinary IgG losses appears to be a function of the membrane area-fraction occupied by the enlarged pores.

Alterations in blood elements in the pathogenesis of diabetic retinopathy.

The role of altered blood elements in the pathogenesis of retinal ischemia and diabetic retinopathy and the relationship to abnormal carbohydrate metabolism and to elevated levels of growth hormone are discussed. These changes involve red blood cells, platelets, plasma proteins, fibrinolytic response, and vascular endothelium. The significance of blood elements mediated by plasma is noted with aggregation of normal red cells when cross-matched with diabetic plasma and with intensive plasmapheresis, which caused red cell disaggregation and improvement of retinopathy. The relationship of metabolic control to diabetic retinopathy is reviewed and is evident by improvement of retinopathy occurring eight weeks after continuous subcutaneous infusion of insulin. A hypothesis is presented which integrates the multifactorial processes involved in the pathogenesis of diabetic retinopathy. Only through future research can one prove the implicated mechanisms in the pathogenesis of diabetic retinopathy and the role of strict metabolic control in altering the progression of retinopathy.

Retinal injury due to industrial laser burns.

Ocular industrial lasers burns in seven patients were analyzed as to cause, severity, and type of injury. Ocular damage ranged from minimal retinal burns to extensive areas of damage with commotio retinae and vitreous hemorrhage. Visual loss ranged from complete recovery without residual defect to a profound decrease in central acuity. The kinds of lasers causing these injuries were neodymium YAG, argon, krypton, and rhodamine dye. Severity of injury was related to several factors. Some degree of carelessness was involved in all injuries.

Infrequency of retinal neovascularization following central retinal vein occlusion.

Forty-eight patients with the clinical diagnosis of central retinal vein occlusion and ten surgically enulceated eyes with central retinal vein occlusion documented by histopathologic examination were studied and reviewed. Retinal neovascularization developed in only one of the ten eyes. Rubeosis iridis occurred in 14% (7) of the clinical cases and in all of the histopathologic cases. Ten eyes with neovascular glaucoma, enucleated following central retinal vein occlusion, showed absence of retinal endothelial cells. The absence of retinal capillary endothelial cells is significant in explaining the rare occurrence of retinal neovascularization following central retinal vein occlusion. However, the small number of cases may reflect a biased result. Further studies of more cases over a longer period are required to reach the final conclusion.

Infrequency of retinal neovascularization following central retinal vein occlusion attributed to endothelial death.

48 patients with central retinal vein occlusion by clinical diagnosis and 10 eyes by histopathological documentation were studied and reviewed. Only 1 eye developed retinal neovascularization. Rubeosis iridis occurs in 14% of clinical cases and all of histopathologic cases. 10 long-standing neovascular glaucoma enucleated eyes following central retinal vein occlusion show absence of retinal endothelial cells. The absence of retinal capillary endothelial cells seems to be significant in explaining the rare occurrence of retinal neovascularization following central retinal vein occlusion. However, the small number sampling may reflect a biased result. Further prospective studies with more cases and time observation are required to draw the final conclusion.

Techniques of argon laser photocoagulation of diabetic disk new vessels.

Four argon laser techniques have been evaluated in the eradication of diabetic disk neovascularization: focal (nonfeeder) photocoagulation, feeder-frond photocoagulation alone, panretinal photocoagulation alone, and feeder-frond treatment combined with panretinal photocoagulation. Focal photocoagulation was dangerous and the least effective technique in preventing recurrence of neovascularization. Feeder-frond photocoagulation was effective initially, but was associated with a high incidence of recurrent neovascularization. Panretinal photocoagulation and panretinal photocoagulation combined with feeder-frond treatment produced results superior to those obtained with the two earlier techniques. The best results were obtained with combined feeder-frond and panretinal photocoagulation done concurrently. Early diagnosis, aggressive photocoagulation therapy, and close follow-up were essential in order to obtain good results.

The effect of pan-retinal photo-coagulation on rubeosis iridis.

Fifteen eyes of 11 patients with rubeosis iridis and angle neovascularization associated with retinal vascular disorders were treated with pan-retinal photocoagulation. In seven of the 15 eyes, the new vessels on the surface of the iris and in the angle regressed after pan-retinal photocoagulation therapy for disk neovascularization; five of the remaining eight eyes that were treated prospectively demonstrated similar involution of the rubeosis iridis. In three of the five preexisting peripheral anterior synechiae regressed and angle structures previously obscured became visible. Three to 36 months after therapy, three eyes developed a few new abnormal iris and angle vessels.

Complications of argon laser retinal photocoagulation: a five-year study.

The operator must become familiar with the dangers involved with argon laser photocoagulation. The hazards in the use of the argon laser slit-lamp photocoagulator derive from the same properties of the instrument that make it advantageous for the treatment of retinal vascular diseases: the wavelengths are highly absorbed by blood, and the beam can be focused to a small diameter. Of course complications can be avoided entirely by using applications so light the virtually no effect is obtained; but such an approach, although safe, cannot be therapeutic.

Subretinal fibrous membrane following argon laser photocoagulation of presumed histoplasmic maculopathy.

Following an initial improvement after argon laser slit-lamp photocoagulation of histoplasmic choroiditis, progressive visual loss occurred. Histopathological examination showed a dense fibrous membrane between Bruch's membrane and the sensory retina. There was no recurrence of hemorrhage or subretinal fluid. This case report provides an explanation for visual loss in the absence of recurrent inflammation or vascular leakage.