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Background: The objective of this study was two-fold: (1) to investigate hematologic abnormalities associated with various types of retinal vein occlusion (RVO) and comparison of their prevalence among those various types of RVO; (2) to review the conflicting literature on the subject, to place the information in perspective. Methods: In patients with various types of RVO seen in our clinic since 1973, we conducted planned prospective studies on the prevalence of: (1) routine hematologic tests (535 patients) and (2) certain special hematologic parameters (platelet aggregation, antithrombin III, and ∝2 globulin in 110, 81 and 91 patients, respectively). Patients were categorized into six types of RVO, based on defined criteria: non-ischemic and ischemic central RVO (CRVO), non-ischemic and ischemic hemi-CRVO (HCRVO), and major and macular branch RVO (BRVO). The patients had a detailed ophthalmic, systemic and hematologic evaluation. The data were abstracted and analyzed retrospectively from the detailed information originally collected prospectively in the patients' records. For data analysis, patients were divided into young, middle-aged and elderly. Observed prevalence rates of hematologic abnormalities were estimated. Logistic regression, adjusting for age and gender, was used to compare the observed prevalence of hematologic abnormalities among the various types of RVO. Results: No generalizations about the prevalence of hematologic disorders in all six types of RVO are possible. Ischemic CRVO showed a significantly higher prevalence of abnormal hematocrit ( P=0.044), hemoglobin ( P=0.018), and blood urea nitrogen ( P=0.025) than non-ischemic CRVO, while a significantly higher prevalence of abnormal antinuclear antibody (ANA; P=0.049) was seen in non-ischemic CRVO than in ischemic CRVO. There was a significant ( P=0.011) difference in the prevalence of abnormal uric acid among the three main RVO groups (CRVO, HCRVO, BRVO), highest in BRVO and lowest in HCRVO. There was a higher prevalence of abnormal glucose ( P=0.069) and ANA ( P=0.071) in CRVO+HCRVO than in BRVO. Results of special hematologic studies are given. Conclusions: Our study showed that a variety of hematologic abnormalities may be seen in association with different types of RVO, and any generalization about these disorders applied to all RVO patients may be misleading. The evidence of our study and in the literature indicates that there is no good reason why all patients with RVO should be subjected to extensive, expensive, special hematologic and hypercoagulability investigations, unless, of course, there is some clear indication; the routine, inexpensive hematologic evaluation is usually sufficient for RVO patients. Treatment with anticoagulants or platelet anti-aggregating agents may adversely influence the visual outcome, without any evidence of protective or beneficial effect. [ABSTRACT FROM AUTHOR]

We conducted a prospective, planned study of argon laser panretinal photocoagulation (PRP) in ischemic central retinal vein occlusion (CRVO) over a 10-year period in 123 eyes. On comparing the lasered eyes versus the nonlasered eyes, there was no statistically significant difference between the two groups in the incidence of development of angle neovascularization (NV), neovascular glaucoma (NVG), retinal and/or optic disc NV, or vitreous hemorrhage, or in visual acuity. Our study, however, did show a statistically significant ( P= 0.04) difference in the incidence of iris NV between the two groups, with iris NV less prevalent in the laser group than in the nonlaser group, but only when the PRP was performed within 90 days after the onset of CRVO. The other parameter which showed a statistically significant difference between the two groups was the peripheral visual fields - the laser group suffered a significantly ( P≤0.03) greater loss than the non-laser group. We discuss the implications of these findings in light of the natural history of ischemic CRVO and of ocular NV. Since the original rationale for advocating PRP in ischemic CRVO was the proven beneficial effect of PRP on ocular NV in proliferative diabetic retinopathy, we also discuss the disparities in the disease process between ischemic CRVO and proliferative diabetic retinopathy and in their responses to PRP. [ABSTRACT FROM AUTHOR]

We investigated prospectively in 128 patients (140 eyes) the role of six routine clinical tests in the differentiation of ischemic central retinal vein occlusion (CRVO) from non-ischemic CRVO during its early acute phase. There were four functional tests [visual acuity, visual fields, relative afferent pupillary defect (RAPID), electroretinography (ERG)] and two morphologic tests (ophthalmoscopy and fluorescein fundus angiography). We found that none of the six tests had 100% sensitivity and specificity in such a differentiation during the early, acute phase, so that no one test can be considered a 'gold standard'; however, combined information from all six is almost always reliable. Overall, the four functional tests proved far superior to the two morphologic tests in differentiating ischemic from non-ischemic CRVO: RAPID was most reliable in uniocular CRVO (with a normal fellow eye), followed closely by ERG in all cases; combined information from RAPID and ERG differentiated 97% of cases; perimetry was the next most reliable, followed by visual acuity. The two morphologic tests performed worst; fluorescein angiography provided either no information at all on retinal capillary nonperfusion (in at least one-third of the eyes during the early, acute phase) because of multiple limitations, or sometimes provided misleading information. Ophthalmoscopic appearance is the least reliable, most misleading parameter. [ABSTRACT FROM AUTHOR]

In 149 eyes with central retinal vein occlusion (CRVO), we prospectively investigated the role of routine, clinical electroretinography (ERG) in differentiating ischemic (60 eyes) from nonischemic CRVO (89 eyes). Single-flash photopic and scotopic ERGs were recorded. Data for the amplitudes and implicit times of a- and b-waves and for the b-/a-wave amplitude ratio were analyzed in detail. The study revealed that the best ERG parameter (for both photopic and scotopic ERG) for differentiating ischemic from nonischemic CRVO was a subnormal b-wave amplitude (reduced to ≤ 60% or by ≥ 1 SD from the normal mean value, or ≤ 64%-69% of that in the fellow normal eye), with a sensitivity of 80%-90% and a specificity of 70%-80%. ERG findings were correlated with the relative afferent pupillary defect (RAPD). An RAPD of ≥ 0.7 log units showed a sensitivity of 88% and a specificity of 90% in differentiating ischemic from nonischemic CRVO. ERG and RAPD findings showed a good correlation. The combined ERG and RAPD tests could differentiate 97%-100% of ischemic from nonischemic CRVO cases, with a specificity of about 70%. [ABSTRACT FROM AUTHOR]