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To determine the optimal area of retinal photocoagulation required for suppressing active neovascularisation (NVI) associated with diabetic retinopathy. We studied 1 eye each of 4 patients in whom active NVI was ophthalmoscopically shown to have been suppressed by additional photocoagulation. These patients initially underwent pan-retinal photocoagulation for diabetic retinopathy at another hospital, but NVI developed subsequently. We compared the areas of photocoagulation before and after additional photocoagulation and compared the area of retinal photocoagulation. The photocoagulated areas before and after additional photocoagulation in the four eyes were 20.7 and 45.2, 36.6 and 56.3, 30.4 and 67.4, and 11.7 and 53.4 %, respectively. The area of retinal photocoagulation required to suppress active NVI is calculated to be ~50 %.

Effective mechanisms of laser photocoagulation for neovascularization in diabetic retinopathy were investigated in regard to change in oxygen pressure in the retina and vitreous and cytokines related to ischemia. The mechanism of laser photocoagulation is suggested to be as follows. 1. Destruction of the outer retina, especially of photoreceptors that have high oxygen consumption decreases metabolic function of the outer retina and its oxygen consumption. 2. The destruction allows increase of oxygen diffusion from choroidal vessels to inner retina, which improves the metabolic function by equilibrating oxygen demand and supply in the inner retina. (3) Production and secretion of neovascular factors such as vascular endothelial growth factor (VEGF) is decreased by the improvement of hypoxia. 4. The neovascularization is decreased by the synergistic effect between the neovascular factors and suppressors such an VEGF, fibroblast growth factor (FGF), and transforming growth factor-beta (TGF-beta). The improvement of the retinal ischemia and the decrease of cytokines are implicated in the regression of neovascularization by the laser photocoagulation for diabetic retinopathy.

The study enrolled 59 eyes with rubeosis iridis and proliferative diabetic retinopathy. The efficacies of two types of panretinal photocoagulation ('full' and 'mild' scatter) on the course of diabetic rubeosis iridis were compared. The mean posttreatment follow-up period was 22 +/- 4.8 months. After application of full-scatter photocoagulation (1,200-1,600 spots) in 27 eyes, rubeosis iridis regressed in 70.4% cases, remained unchanged in 14.8% and deteriorated in 14.8%. After mild-scatter photo-coagulation (400-650 spots) in 32 treated eyes, rubeosis iridis regressed in 37.5% cases, 34.4% was unchanged, while deterioration was found in 28.1%. A better therapeutic effect of panretinal photocoagulation in regression of diabetic rubeosis iridis was obtained, if the total dose of the applied laser spots was higher.

Subfoveal choroidal neovascularization generally carries a poor visual prognosis. This review traces the evolving vitreoretinal surgical techniques for the treatment of this entity. Extensive retinotomies to expose large submacular scars caused frequent complications and poor visual results. More recently, small retinotomy techniques with manipulation of subfoveal membranes behind neurosensory retina have been described. Removal of subfoveal neovascularization with this latter approach is summarized. Visual results are variable. If foveal retinal pigment epithelium can be preserved, excellent central visual function can be regained. In the majority of subfoveal membranes, surgical removal creates retinal pigment epithelium defects, and acuity is limited. These approaches merit further evaluation.

The author treated experimentally produced choroidal neovascularization (ChNV) with mild dye laser photocoagulation (PHC). We treated these ChNVs with 590 nm wavelength, 200 microns spot size, 0.2 second duration and 50 mW of power. Eleven eyes of nine rhesus monkeys were used. Then these ChNVs were examined clinically and histopathologically at 24 hours, 2 weeks and a month after therapeutic PHC. Small ChNVs, less than 1/3 disc diameter healed successfully and histopathologically most of them were coagulated and disappeared. A few poorly developed ChNVs remained, but were well enveloped by the proliferating retinal pigment epithelial (RPE) cells. On the other hand, ChNVs of more than 1/3 disc diameter did not respond to weak PHC, grew actively over a month, and were not completely surrounded by proliferating RPE cells. These results suggest that by mild PHC, small ChNVs may be treatable, however, in large ChNVs, mild PHC may rather accelerate their activity.

The effect of scatter photocoagulation on the perfusion of iatrogenic choriovitreal neovascularisation (CVN) has been assessed by a randomised trial in 35 CVN lesions in 18 eyes with proliferative sickle retinopathy. No difference in size or vascularity of CVN lesions was apparent between the nine treated and nine control eyes over a median follow-up of 42 months. Scatter photocoagulation by the stated protocol was not effective in the treatment of CVN.

We prospectively studied the safety and efficacy of subfoveolar laser treatment of choroidal neovascular membranes (CNVM) in 29 eyes. With one to four treatments, all CNVMs were successfully eradicated. Central visual acuity improved in 31% and stabilized in 69%. Vision did not deteriorate in any of the eyes. In appropriately selected eyes, subfoveolar treatment appears safe and effective in halting the exudative response and minimizing scotoma size, thus facilitating the use of low-vision aids.

A clinical trial has been conducted to evaluate the effect on vision of laser treatment (argon green or krypton red lasers, assigned randomly) compared with no treatment of eyes with subfoveal choroidal neovascularization associated with age-related macular degeneration. Three months after enrollment, the visual acuity of 37 (20%) of 184 laser-treated eyes had decreased 6 or more lines from the baseline level, while only 19 (11%) of 178 untreated eyes had suffered such large decreases (P = .01, chi 2 test). However, 24 months after enrollment, the visual acuity of only 23 (20%) of 114 laser-treated eyes had decreased by 6 or more lines from baseline compared with 41 (37%) of 112 untreated eyes (P less than .01, chi 2 test). On average, after 24 months, visual acuity of laser-treated eyes had decreased 3 lines from baseline, and visual acuity of untreated eyes had decreased 4 lines (P = .003, t test). Laser-treated eyes retained contrast threshold for large letters at or near baseline levels through 36 months of follow-up examinations, while the contrast threshold of untreated eyes worsened. Persistent or recurrent neovascularization was observed in 51% of the laser-treated eyes by 24 months after initial treatment but was not associated with decreased visual acuity. None of the findings suggested a reason to favor either the argon green or krypton red wavelength. Laser treatment of subfoveal neovascular lesions that meet the eligibility criteria for this study is recommended if both the patient and the ophthalmologist are prepared for a large decrease in visual acuity immediately after treatment.

In a controlled clinical trial, 160 eyes underwent "perifoveal" laser photocoagulation. All patients had age-related macular degeneration and subfoveal neovascularization (0.5 to 2.5 disc diameters), without detectable fibrous tissue, and visual acuity from 20/100 to 20/1000. At least 1 year of follow-up has been completed in 127 eyes. Visual acuity was maintained or improved in 12 (20.3%) of 59 untreated eyes vs 28 (41.1%) of 68 treated eyes (P = .04). Reading visual acuity (J4) with the use of low-vision aids was retained in 28 untreated eyes (47.4%) vs 50 treated eyes (73.5%) (P less than .01). Automated static perimetry showed an increased scotomatous area and/or depth with eccentric fixation in all but four patients. A flat atrophic scar was achieved in 53 of 68 treated eyes. Statistical analysis indicated that perifoveal photocoagulation has been effective in the short-term preservation of visual acuity.

In a randomized clinical trial, the effects of laser treatment of subfoveal recurrent neovascularization have been compared with no additional laser treatment. Among eyes with age-related macular degeneration assigned to laser treatment of recurrent neovascularization (n = 97) and those assigned to no additional laser treatment (n = 109), average visual acuity was 20/125 (Snellen equivalent) at entry. Both at 3 and 24 months after enrollment, the average visual acuity of laser-treated eyes was 20/250, indicating a decrease in visual acuity of 3 lines immediately after treatment, but little further decrease in acuity thereafter. In contrast, the average visual acuity of eyes assigned to no additional treatment decreased by 2 lines to 20/200 by 3 months after entry. After 24 months, acuity had decreased an additional 2 lines to 20/320. By 24 months after enrollment, only three (9%) of 35 laser-treated eyes, but 13 (28%) of 46 untreated eyes, had decreased visual acuity of 6 or more lines from baseline (P = .03, chi 2 test). On average, treated eyes maintained the initial contrast threshold for large letters, while the contrast threshold of untreated eyes worsened steadily throughout 24 months of follow-up. This study was halted before the target number of patients had been enrolled because of the similarity of these findings to findings from a related Macular Photocoagulation Study clinical trial of laser treatment of subfoveal neovascularization secondary to age-related macular degeneration in eyes without previous laser treatment. Laser treatment is recommended for subfoveal recurrent neovascularization in eyes with age-related macular degeneration that meet the eligibility criteria for this study.

To investigate the potentially harmful effects of laser photocoagulation in the papillomacular bundle (PMB), the records of patients treated for idiopathic neovascular membranes or membranes secondary to histoplasmosis extending into the PMB were reviewed. Twenty-eight eyes of 27 patients were identified. Most eyes (75%) were treated with the krypton red laser, while the remainder (25%) were treated with either argon green (18%) or a combination of the two (7%). After treatment 21 eyes (75%) had stable or improved visual acuity and three eyes (11%) lost more than three lines. Four eyes (14%) had changes in the optic disc and one eye developed a permanent arcuate scotoma. These data suggest that severe visual loss and extensive visual field defects occur rarely after photocoagulation of peripapillary choroidal neovascular membranes.

The authors report the occurrence of occlusive retinal arterial disease and retinal neovascularisation in a 44-year-old woman with systemic lupus erythematosus (SLE). Two days after uncomplicated panretinal photocoagulation the patient developed an acute anterior segment ischaemic syndrome. To our knowledge this complication has not been reported in any other patient following laser photocoagulation or in association with SLE.

Eales' disease is an extremely uncommon vasoproliferative retinal disease predominantly affecting otherwise healthy young men. The etiology of this condition is unknown, but its progression and clinical appearance are similar to other vasoproliferative diseases of the retina such as diabetic and sickle cell retinopathies. These similarities make Eales' disease a good prospect for inclusion in a model pattern of retinal ischemic disease and suggest that treatment by panretinal photocoagulation should be effective in this condition. We had good results in treating eight eyes diagnosed as having Eales' disease with scattered laser photocoagulation.

Untreated subfoveal choroidal neovascularization (SFCN) often progresses to destroy much central visual function. In this study, laser photocoagulation which included the entire foveal avascular zone was applied to SFCN in the second eye of 13 consecutive patients. Each patient had untreated SFCN in their first eye with visual acuity less than or equal to 20/400. Each second eye had SFCN of recent onset which was less than or equal to 1 disc diameter (DD) in size and visual acuity less than or equal to 20/200. In 10 of 13 (76.9%) treated eyes, SFCN was eliminated for 3 to 30 months. These eyes all retained strikingly better visual fields (Amsler or automated) than their fellow untreated eyes, markedly better subjective vision, and Snellen visual acuities of 20/70 to 20/400. Foveal photocoagulation may be useful in selected cases of SFCN with small neovascular nets and poor visual acuity.

A patient who developed intravitreal ciliary body neovascularization following cyclocryotherapy for neovascular glaucoma is presented. Presenting vitreous hemorrhage limited her visual acuity to 20/200. After panretinal photocoagulation, the intravitreal ciliary body neovascularization regressed, the vitreous hemorrhage cleared, and the patient's visual acuity was 20/30. The possible pathogenesis of intravitreal ciliary body neovascularization is reviewed, and the reason for regression of the neovascular tissue is hypothesized.

Clinical research utilizing the yellow, orange, and red wavelengths of the dye laser (Rhodamine 6G and MD-631) appears to have considerable promise and may demonstrate that the liquid organic dye laser is the laser of choice for photocoagulation of many types of ocular defects. The effectiveness of the dye laser as a photocoagulation source is due to the trans-spectral availability of relatively high output power wavelengths. Therefore, a target tissue can be selectively coagulated with minimal laser energy transmitted through the refractive media and minimal damage to nearby normal tissues. The dye laser, as a photocoagulation system, should prove valuable in the therapy of many ocular diseases.

The visual outcome of 20 eyes of 20 patients with peripapillary subretinal neovascular membranes (SRNVM) treated with krypton red laser photocoagulation (KRLP) was studied. Complete obliteration of the SRNVM was achieved in all eyes in the study. In 18 of 20 patients, the visual acuity improved or remained the same during an average follow-up of 9.9 months. There were no treatment-related complications. The efficacy of KRLP in the management of patients with peripapillary SRNVM is discussed.

The authors present a randomized study of 27 eyes affected by pathological myopia with macular subretinal neovascularization which were treated with a tunable dye laser. The effectiveness of three different wavelengths (577, 590 and 620 nm) in the direct treatment of subretinal neovascularizations was evaluated in 3 groups of 9 patients each. Statistical analysis of both visual and anatomical results did not show significant differences among the three wavelengths used.

The histology of macular photocoagulation is reviewed. This information may be helpful in selecting the best available laser for retinal vascular and choroidal disorders in the macular region, as providing an experimental method to better understand the effects of photocoagulation on retinal disease processes.

Corneal argon laser photocoagulation (CALP) was used in 13 patients to treat deep stromal vascular ingrowth. Eight patients had undergone successful penetrating keratoplasty but had developed deep stromal vessels into the graft associated with signs of graft rejection, which did not improve with steroid treatment alone (group 1). After CALP, there was marked regression of the neovascularization with reversal of graft rejection in all eyes. Three additional patients with vascularized corneas, referred for penetrating keratoplasty, underwent CALP preoperatively with obliteration of the vessels (group 2). Two of these patients have since undergone keratoplasty and, in both, the grafts have remained avascular and clear over a 21-month follow-up. Two other patients with corneal injury and progressive corneal opacification and vascularization have also been treated with CALP (group 3). CALP may be a useful adjunct in the treatment of corneal neovascularization. Further clinical studies are needed to define its exact role.

Laser treatment of a subretinal neovascular membrane associated with a unilateral choroidal osteoma in a 28-year-old woman is described. To our knowledge, this is the first reported use of krypton red laser photocoagulation for the initial treatment of a subfoveal neovascular membrane in this setting. Early recognition of the membrane allowed treatment prior to involvement of the central fovea. Follow-up has shown obliteration of the membrane without recurrence and 20/20 vision. We emphasize recognition of this unusual tumor, self-monitoring with an Amsler grid, and early treatment of subretinal neovascularization in this high risk group of young patients.

We studied 124 consecutive eyes that had laser photocoagulation for choroidal new vessel membranes (NVM) associated with pigment epithelial detachment (PED). In many cases, the extent of the NVM was uncertain. We thought it was not subfoveal in all cases but it possibly may have been subfoveal in one subgroup of cases. With a mean follow-up of 16 months, vision was stable or improved in 53% of the treated eyes. There was no difference in outcome between argon-treated and krypton-treated eyes. On the basis of fluorescein angiograms, we classified 86 of the eyes into four nonexclusive groups. Vision was stable or improved in 68% of eyes with juxtafoveal or extrafoveal PED, 48% with subfoveal PED, 76% with juxtafoveal or extrafoveal NVM, and 50% of eyes with possibly subfoveal NVM. A randomized clinical trial of laser photocoagulation for NVM in PED is both indicated and warranted. A pilot study under the auspices of the Macular Photocoagulation Study is now under way to determine the feasibility of and develop a protocol for such a trial.

A retrospective study was performed on 75 eyes with presumed ocular histoplasmosis syndrome and 59 eyes with aging macular degeneration to determine risk factors for visual loss in the early postoperative period after successful laser photocoagulation of primary and recurrent choroidal neovascular membranes (CNVMs). Despite successful obliteration of neovascularization, visual loss of two lines or greater occurred in 18.8% of eyes with presumed ocular histoplasmosis syndrome and 40.4% of eyes with aging macular degeneration (mean follow-up, 33.6 weeks). Factors which predicted visual loss after treatment included a short distance of CNVMs from the foveal center (P = 0.002), good preoperative visual acuity (P = 0.003), increased area of CNVM (P = 0.025), and postoperative internal limiting membrane wrinkling (P = 0.017). Eyes with CNVMs greater than 0.8 mm2 in area or less than 0.6 mm from the foveal center had at least twice the frequencies of visual loss of eyes without these characteristics.

A group of 20 patients (28 eyes) with proliferative retinopathy who required extensive argon laser photocoagulation to induce regression of new vessels is presented. The mean number of burns applied to each eye was 7225, with a maximum of 11,513. These were delivered in a mean of nine sessions over a mean period of 22.9 months. Twenty-five eyes (89%) had a final visual acuity of 6/18 or better. The remaining three eyes (11%) had severely reduced vision attributable to complications of proliferative diabetic retinopathy (traction retinal detachment involving the macula in two eyes and ischaemic maculopathy and a persistent vitreous haemorrhage in the third). Large amounts of confluent argon laser photocoagulation may be necessary for the elimination of new vessels in some patients, and it is our view that laser photocoagulation should be continued until regression of new vessels occurs. This is compatible with the retention of functional vision and good visual acuity.

Retinal revascularization developed within the treatment scar in 7% of patients who had laser photocoagulation treatment for a choroidal neovascular membrane. This revascularization could be mistaken for recurrent choroidal neovascularization because it initially proliferated into a glomerularlike structure and showed dye leakage on angiography. Unlike choroidal neovascularization, these vessels, however, filled entirely from the retinal circulation and stereoscopic angiograms showed them to be located in the inner retina. In the 20 patients who were followed up, the retinal revascularization first appeared approximately four weeks after treatment and persisted for an average of ten weeks. It was associated with dense laser scarring, retinal capillary obliteration, and internal limiting membrane wrinkling, suggesting that heavy initial laser treatment was a predisposing factor for its development. It is important to differentiate retinal revascularization, which has an excellent prognosis and does not require re-treatment, from recurrent choroidal neovascularization, which usually must be treated promptly to avoid loss in visual acuity.

The eye of a patient with age-related macular degeneration was treated with krypton laser photocoagulation and later studied histopathologically. Five months after treatment the original membrane was completely obliterated, but a separate new membrane was found, which was fed by the retinal circulation and not by the choroid. The frequency of such recurrences is not known, but they may be related to krypton laser treatment.

One day before enucleation for choroidal melanoma, four patients consented to experimental laser photocoagulation for the purpose of comparing the histopathologic appearance of acute chorioretinal lesions produced by various dye laser wavelengths with krypton red and argon green laser controls. Three patients had simulated "light" and "heavy" treatment of an extrafoveal choroidal neovascular membrane (CNVM) with wavelengths 577 nm (yellow), 595 nm (orange), and 600 nm (orange). One patient had simulated panretinal photocoagulation (PRP) with four different dye laser wavelengths. Extrafoveal "light" treatment with the three dye wavelengths and both controls spared the inner retina and produced similar effects in the outer retina, pigment epithelium, and choriocapillaris. Choroidal penetration was deepest with the longer wavelengths (590-647 nm) in both "light" and "heavy" treatment groups. "Heavy" treatment gave varying degrees of full-thickness retinal uptake for all dye and both control wavelengths. Both ends of the orange spectrum (590-600 nm) produced the most severe inner retinal uptake. Panretinal photocoagulation produced similar full-thickness retinal uptake for all four dye wavelengths tested. These results indicate that caution should be used when treating "heavily" with 590 and 600 nm in the extrafoveal area.

Disc neovascularization developed in one eye of a 40-year-old white woman with the acute retinal necrosis syndrome. Krypton laser scatter photocoagulation was placed in areas of nonnecrotic and segmentally nonperfused retina that were demonstrated by fluorescein angiography. Marked reduction in disc neovascularization was noted clinically 16 days after laser treatment and was confirmed angiographically 4 weeks after treatment. Neovascularization was completely regressed at 9 weeks after treatment. The authors postulate that the retinal vasculitis and nonperfusion produced retinal ischemia which stimulated neovascular proliferation, and that photocoagulation caused regression of the neovascularization.

Panretinal photocoagulation (PRP) is widely used for a variety of ischemic ocular conditions. In diseases that produce neovascularization of the iris (NVI), such as diabetes mellitus and central retinal vein obstruction, a judiciously timed PRP can reduce the incidence of neovascular glaucoma. Neovascularization of the iris can occur after central retinal artery obstruction (CRAO) as well. In this article, the authors report the outcome of 17 patients who received PRP to treat rubeosis iridis secondary to CRAO. Eleven of the 17 patients (65%) showed regression of NVI after PRP. Although the uncontrolled and retrospective nature of this study precludes drawing definitive conclusions from these data, PRP appears to be effective in reducing the incidence of neovascular glaucoma, if it is delivered before the development of elevated intraocular pressure (IOP). Once neovascular glaucoma occurs, additional modalities appear to be necessary in order to adequately control the elevated IOP.

Thirty-seven eyes initially treated with argon blue-green, argon green, or krypton red laser photocoagulation demonstrated a recurrent subretinal neovascular membrane (SRNVM) at the edge of the treatment scar extending into the foveal avascular zone and were retreated with krypton red laser photocoagulation. The subretinal neovascular membrane was due to the presumed ocular histoplasmosis syndrome (POHS) in 10 eyes, aging macular choroidal degeneration (AMCD) in 22 eyes, and miscellaneous causes in five eyes. Anatomic success, defined as complete obliteration of the recurrent SRNVM, was achieved in 26 eyes (70%). When compared to pretreatment visual acuities, 23 of 37 eyes (62.2%) had stable or improved postoperative visual acuities during the follow-up period. Twenty-six eyes were retreated one time; nine eyes required two retreatments; and two eyes required three retreatments. Final visual results showed visual acuity greater than or equal to 20/40 in 7 eyes (18.9%); visual acuity greater than or equal to 20/80 in 16 eyes (43.8%); visual acuity greater than or equal to 20/100 in 19 eyes (51.4%); visual acuity greater than or equal to 20/200 in 27 eyes (73%); and visual acuity greater than or equal to 20/400 in 34 eyes (91.9%).