Effect and compatibility of isovolaemic haemodilution in the treatment of ischaemic and non-ischaemic central retinal vein occlusion

[Retinal vein occlusion management algorithm. Part 1. Classification, diagnosis, and acute-stage treatment]

Considering an upward global trend in cardiovascular disease rates, retinal vein occlusion (RVO) in particular, development of therapeutic guidelines is a pressing issue in ophthalmology. Risk factors for RVO include hypertension, atherosclerosis, diabetes mellitus, blood disorders, inflammatory disorders, and prescription drug use. Three stages of RVO have been identified. By location, the entity can be divided into three big groups: central retinal vein occlusion (CRVO), branch retinal vein occlusion (BRVO), and hemicentral retinal vein occlusion (HCRVO), each being either ischemic or nonischemic. Functional prognosis is better in nonischemic occlusions. Patient management comprises acute-stage treatment (anticoagulants, fibrinolytic agents, and hemodilution) and struggling with ocular complications (intravitreal injections and laser coagulation). It is essential that primary assessment and follow-up of patients at any stage of RVO include optical coherence tomography and fluorescent angiography.

Intravitreal ranibizumab versus isovolemic hemodilution in the treatment of macular edema secondary to central retinal vein occlusion: twelve-month results of a prospective, randomized, multicenter trial

PURPOSE

This is a prospective, randomized, multicenter, investigator-initiated trial to evaluate the 12-month effectiveness of isovolemic hemodilution (IH) with prompt versus deferred intravitreal injections (IVI) of ranibizumab 0.5 mg for the treatment of macular edema secondary to early central retinal vein occlusion (CRVO).

METHODS

Eyes with macular edema due to CRVO having occurred not more than 8 weeks previously received either monthly ranibizumab IVI in combination with IH (group I, n = 28) or IH alone (group II, n = 30). From month 2 to 12, the patients in both groups could be treated with monthly intravitreal ranibizumab. The main outcome variables were gain of visual acuity and the course of central retinal thickness as measured with optical coherence tomography.

RESULTS

At 12 months, eyes in group I on average gained +28.1 (±19.3) letters compared to +25.2 (±20.9) letters in group II (p = 0.326). This result was achieved with significantly fewer injections in group II. Additionally, 30% of the eyes in group II did not need ranibizumab IVI during the 12 months of the trial.

CONCLUSION

Ranibizumab IVI in addition to IH proved to be highly effective in increasing visual acuity and reducing macular edema secondary to CRVO. Initial IH in early CRVO may be a first treatment option in patients anxious about IVI.

Pathogenesis, prevention, diagnosis and management of retinal vein occlusion

Retinal vein occlusion (RVO) is the second vascular retinal cause of visual loss and defined by the occlusion of a retinal vein. It is divided into branch retinal vein occlusion or central retinal vein occlusion, depending on the location of occlusion. RVO has severe medical, financial and social implications on the patients. The diagnosis of the disease is easier nowadays with the use of spectral domain optical coherence tomography and fluorescein angiography. The treatment options for RVO have changed dramatically over the past few years with the introduction of the intravitreal injections of dexamethasone (Ozurdex), bevacizumab (Avastin), ranibizumab (Lucentis) and aflibercept (EYLEA), along with the panretinal laser photocoagulation, abandoning former treatment modalities and surgical solution. This manuscript is a review of current literature about RVO with emphasize on the pathophysiology, risk factors and prevention, diagnosis and sub-group categorization and treatments including medical and surgical. Since no official guidelines are available for the treatment of RVO patients, and considering the latest developments in the treatment options, and the variety of follow-up and treatment modalities, this manuscript aims to provide tools and knowledge to guide the physician in treating RVO patients, based on the latest publications from the literature and on several of the patients characteristics.

Management of retinal vein occlusion--consensus document

Retinal vein occlusion (RVO) can have severe consequences for the people affected by the disease, including visual loss with costly social repercussions. Currently, there is no European consensus with regard to the management of RVO. Following a careful review of the medical literature as well as the data from several clinical trials, a collaborative group of retina specialists put forth practical recommendations based on the best available scientific evidence for the clinical approach to RVO. Taking into consideration the recent advances in diagnostic tools and management options, the present document aims to provide the European ophthalmologists with guidelines for clinical practice to the benefit of their patients.

Hemodilution therapy using automated erythrocytapheresis in central retinal vein occlusion: results of a multicenter randomized controlled study

BACKGROUND

Central retinal vein occlusion (CRVO) leads to poor visual outcome in most eyes. Abnormal hemorheology was suspected to play a major role in its pathogenesis. CRVO treatment is still a matter of debate but several studies have pointed out the efficacy of isovolumic hemodilution. The aim of this study was to assess the feasibility and efficacy of hemodilution using automated erythrocytapheresis in recent-onset CRVO.

METHODS

In this prospective randomized controlled multicenter study, 61 consecutive CRVO patients were enrolled when they met the following criteria: CRVO lasting for 3 weeks or less, visual acuity ranging from 20/200 to 20/32, age between 18 and 85 years, no diabetes, no uncontrolled systemic hypertension, no antiplatelet or anticoagulant therapy, hematocrit higher than 38%, and signed informed consent. Patients were randomly assigned to the hemodilution group (n = 31) or to the control group (n = 30). Hemodilution therapy consisted of one session of erythrocytapheresis on outpatient basis, followed by additional session(s) for 6 weeks if needed. Target hematocrit was 35%. Follow-up was 12 months.

RESULTS

No statistical differences in age, associated risk factors, or CRVO characteristics were observed at baseline between both groups. Mean visual acuity was equivalent to 20/80 in the hemodilution group and to 20/63 in the control group (non-significant difference). In the treated group, mean number of hemodilution sessions was 3.3 (range, 1 to 6), and no major side-effects occurred. At the 12-month follow-up visit, 64.5% of the hemodilution group had visual acuity of 20/40 or better compared to 40% of the control group (p = .048). Visual change was a gain of 1.7 ETDRS line in the hemodilution group versus a loss of 2.3 lines in the control group (p = .007). There was less conversion into an ischemic form in the hemodilution group (11%) than in the control group (50%, p = .004). Mean final retinal thickness was 289 μm in the hemodilution group versus 401 μm in the control group (p = .068).

CONCLUSIONS

This multicenter controlled randomized study demonstrated that automated erythrocytapheresis is a safe and effective tool for performing hemodilution and confirmed that hemodilution therapy can improve the final prognosis of CRVO when applied in the early phase of the disease.

Medical treatment of retinal vein occlusions

The medical treatment of retinal vein occlusion (RVO) is comprised of three main stages: identification and therapy of the detectable risk factors, specific treatment aimed at the occlusive form and treatment of RVO complications. Even though the possible medical management of RVO includes several treatments, the most interesting approaches have been: anticoagulant/antiaggregating agents, troxerutin, corticosteroid, fibrinolytic/thrombolytic agents, and hemodilution. Overall, the medical approach to RVO is still awkward and unsatisfactory. Randomized clinical trials are needed to assess the degree of efficacy of the medical treatment of the specific forms of RVO.

[Therapeutic erythrocytapheresis: technical aspects and clinical applications]

PURPOSE

Therapeutic erythrocytapheresis is a selective red cell-depletion aphaeresis technique.

CURRENT KNOWLEDGE AND KEY POINT

Using a discontinuous or continuous flow blood cell separator, the technique safely allows quickly and automatically collecting a large volume of red cells. The main obstacle of implementation is a poor peripheral venous access. The procedure is well-tolerated. Polycythemia vera, hereditary hemochromatosis, complicated sickle-cell-disease and retinal venous occlusion are the main clinical applications.

PROSPECT AND PROJECT

Therapeutic erythrocytapheresis is a more modern and more effective method than the classic patient-bleeding. It has to be preferred in the early treatment of patients with polycythemia vera and hereditary hemochromatosis.

Chirurgische Therapie retinaler Venenverschlüsse

The range of therapeutic options for the treatment of retinal vein occlusions has been decisively extended by three new surgical methods: radial optic neurotomy (RON) and retinal endovascular lysis (REVL) for central retinal vein occlusion, and arteriovenous dissection (AVD/sheathotomy) for branch retinal vein occlusion. None of those methods has been tested in randomised studies meeting the requirements of evidence-based medicine. It is therefore difficult to assess the relative values of the individual procedures and determine in what precise circumstances each is indicated. The difficulties are compounded further by the use of these techniques in association with new and promising intravitreally injected drugs (e.g. steroids and angioinhibitors), which makes it even more difficult to assess the real efficacy of the surgical methods. In this paper we discuss the three different surgical methods and try to evaluate their clinical benefit.

Bevacizumab in retinal vein occlusion-results of a prospective case series

BACKGROUND

Macular edema is the main reason for decreased visual acuity (VA) in early retinal vein occlusion (RVO). Bevacizumab (Avastin, Genentech) is an anti-VEGF substance to treat macular edema triggered by hypoxia-induced expression of vascular endothelial growth factor (VEGF). Initial reports showed a significant reduction of central retinal thickness and improved visual acuity (VA) after bevacizumab injection. To date, only retrospective studies and case reports have been published on bevacizumab treatment of RVO.

METHODS

In this prospective interventional case series, we evaluated the response to a single bevacizumab treatment in 21 RVO patients (14 CRVO, 7 BRVO). Study endpoints were visual acuity (VA) using ETDRS charts and central macular edema (CME) over 9 weeks.

RESULTS

Mean VA from all 21 patients increased by more than 2 lines (2.4+/-0.4 lines; p<0.01 compared to baseline). The improvement of VA after bevacizumab injection was concordant with a decrease in central retinal thickness. Peak VA was reached between 3 and 6 weeks after injection. Between week 6 and 9 a decrease in VA was observed. This VA decrease was precipitated by an increase in CME between week 3 and 6. In subgroup analyses, patients receiving bevacizumab injection within the first 3 months after RVO showed an average VA gain of 4 lines (range 2-7 lines) compared to an average gain of 1.8 (range 1-3) and 2.5 (range 1-7) in patients receiving bevacizumab between 4-6 months and after more than 6 months, respectively.

CONCLUSIONS

Bevacizumab injection is able to improve CME and VA in RVO patients within the first 3 to 9 weeks. We did not observe any short-term adverse effects during our study. As the decrease in VA was anticipated by an increase in central retinal thickness, regular OCT examinations between week 3 and 6 may be helpful for judging the appropriate timing for re-injection in order to maintain patients within the initially reached range of VA until a new balance between inflow and outflow in the retinal circulation is reached.

Retinal endovascular lysis in ischemic central retinal vein occlusion: one-year results of a pilot study

PURPOSE

Retinal endovascular lysis is a new therapeutic option for patients with central retinal vein occlusion (CRVO). In this procedure, a fibrinolytic agent is injected directly into a cannulated retinal vein after pars plana vitrectomy.

DESIGN

Prospective interventional case series.

PARTICIPANTS

Thirteen strictly defined patients with ischemic CRVO.

METHODS

Patients with a decimal visual acuity (VA) of 0.2 or worse were scheduled for surgery within the first 5 months after onset of CRVO. A full ocular examination, determination of VA (Early Treatment Diabetic Retinopathy Study charts), and fluorescein angiography were done preoperatively and 6, 12, 26, and 52 weeks postoperatively.

MAIN OUTCOME MEASURE

Visual acuity 1 year after retinal endovascular lysis. Secondary study end points were (1) correlation of VA and successful recombinant tissue plasminogen activator injection into a retinal vein, (2) complication rate, and (3) number of additional surgical procedures within the first year after retinal endovascular lysis.

RESULTS

All patients had an ischemic CRVO and completed the 1-year follow-up visit. Preoperative decimal VA was 0.063 +0.025/-0.018 (VA range, light perception [LP]-0.2); 6-week postoperative VA, 0.049 +0.024/-0.016 (LP-0.4); 3-month postoperative VA, 0.043 +0.019/-0.014 (LP-0.3); 6-month postoperative VA, 0.035 +0.022/-0.013 (blindness-0.4); and 12-month postoperative VA, 0.04 +0.026/-0.016 (blindness-0.4). Visual acuity changed 1 year after retinal endovascular lysis by -1.923+/-1.619 lines (+6 to -16 lines; P = 0.258). We considered the retinal endovascular lysis procedure to have been technically successful in 10 eyes. Visual changes did not depend on successful lysis. Six eyes developed neovascular glaucoma, of which 2 globes ended up with painful phthisis and had to be removed. Retinal detachment was found in 3 eyes and cataract in 4. Together, the 13 eyes needed 22 additional surgical procedures. Preoperative and postoperative angiographic examinations showed no significant changes.

CONCLUSION

Ischemic CRVO patients did not profit from retinal endovascular lysis in this pilot study. Visual results and the risk of developing iris neovascularization and neovascular glaucoma took the natural course. Although these results may be due to the overall bad prognosis of these particular ischemic eyes, the number of postoperative complications is unacceptably high.

Follow up by colour Doppler imaging of 102 patients with retinal vein occlusion over 1 year

BACKGROUND/AIM

Retinal vein occlusion (RVO) is one of the most frequent ocular vascular diseases and leads to severe vision impairment. Colour Doppler imaging (CDI) is the first method which allows distinct evaluation of arterial and venous velocities in RVO. CDI is valuable for diagnosis of RVO and shows the effects of isovolaemic haemodilution. Patients with RVO were monitored by CDI for 1 year in order to clarify venous and arterial involvement in the pathogenesis of this disease.

METHODS

Patients with RVO were monitored prospectively for 1 year with clinical examinations, fluorescein angiography, and CDI every 3 months. 102 adults referred for RVO for less than 2 months were enrolled. Unaffected eyes were used as control. The maximum systolic and diastolic flow velocities and the resistance index (RI) were measured in the central retinal artery (CRA) and the maximum and minimum blood flow velocities in the central retinal vein (CRV).

RESULTS

During the year of observation, branch retinal vein occlusion (BRVO), ischaemic central retinal vein occlusion (CRVO), and non-ischaemic CRVO had a distinct pattern of venous velocity changes. BRVO had a similar profile to that observed in controls. Venous velocities were continuously lower in central forms, with the lowest values in ischaemic occlusion. In contrast, a brief decrease in arterial diastolic velocity was observed in ischaemic CRVO at presentation, correlated with arteriovenous passage time on fluorescein angiography, but with rapid normalisation.

CONCLUSIONS

CDI findings were correlated with the type of RVO at all times during follow up. CDI showed persistent impairment of central venous velocity in CRVO whereas there was a fast initial values recovery of the arterial velocity. These results using CDI show strong evidence of a primary venous mechanism in RVO.

Superselective ophthalmic arterial fibrinolysis with urokinase for recent severe central retinal venous occlusion: initial experience

PURPOSE

To investigate the effects of local ophthalmic arterial fibrinolysis on central retinal venous occlusion (CRVO).

MATERIALS AND METHODS

Thirteen patients had recent severe nonischemic CRVO for which no alternative therapy was available. A flow-guide microcatheter was introduced coaxially via the femoral artery into the ophthalmic arterial ostium, and urokinase was perfused for 40 minutes. Vision, funduscopic findings, and retinal perfusion were assessed during 1 year of follow-up.

RESULTS

Five of the 13 patients treated experienced visual improvement (P =.05) and retinal perfusion within 24-48 hours. Vision returned to normal within 24-48 hours in three patients, within 1 week in one patient, and within 1 month in one patient. These five patients exhibited progressive lesion regression within 2-4 weeks at funduscopy. Their clinical course prior to treatment resembled that of combined central retinal arterial occlusion (CRAO) and CRVO, which typically has a poor visual outcome. One patient relapsed 1 month after fibrinolysis. Of the remaining eight patients, one had normal vision at 12 months, and seven had no improvement. No technical complications were observed.

CONCLUSION

Although there was no control group, the short period between fibrinolysis and substantial visual improvement, combined with marked retinal perfusion improvement, suggests that fibrinolysis is beneficial for CRVO, especially for recent CRAO and CRVO.

Ultrasound enhanced thrombolysis in experimental retinal vein occlusion in the rabbit

AIMS

To investigate if it was possible to lower the dose of streptokinase and maintain an effective thrombolysis by adding pulsed low energy ultrasound.

METHODS

53 retinal veins in 27 rabbits were occluded by rose bengal enhanced laser treatment. Six rabbits were treated with streptokinase (50,000 IU/kg), 10 rabbits were treated with a low dose of streptokinase (25,000 IU/kg), and 11 rabbits were treated with a low dose of streptokinase (25,000 IU/kg) and pulsed ultrasound during 1 hour. Fluorescein angiography was performed immediately before the thrombolytic treatment and after 12 hours.

RESULTS

In the group treated with streptokinase (50,000 IU/kg) all vessels were open. In the group that was given streptokinase (25,000 IU/kg), 21% of the vessels were open. In the group that was treated with streptokinase (25,000 IU/kg) and ultrasound, 64% of the vessels were open. The difference between groups 2 and 3 is statistically significant (p = 0.011)

CONCLUSION

Adding pulsed low energy ultrasound makes it possible to lower the dose of streptokinase while maintaining a good thrombolytic effect.

Doppler assessment of hemodynamic changes after hemodilution in retinal vein occlusion

PURPOSE

We assessed the usefulness of color Doppler imaging and spectral analysis in monitoring the effect of isovolemic hemodilution on retinal vein occlusion.

METHODS

Color Doppler imaging was used to measure the systolic and diastolic blood flow velocities and the resistance index (RI) in the central retinal artery and the maximum and minimum blood flow velocities in the central retinal vein of affected eyes and contralateral unaffected eyes before and 1 day after isovolemic hemodilution in 70 adults (40 men and 30 women; mean age, 62.4 +/- 13.7 years) who presented with retinal vein occlusion.

RESULTS

With hemodilution, the hematocrit value was decreased from 41.8 +/- 3.0 to 33.0 +/- 3.0. In central retinal vein occlusion, the pretreatment arterial and venous flow velocities of affected eyes were significantly lower than those of unaffected eyes. After hemodilution in eyes affected by ischemic occlusion, a significant improvement in the RI in the central retinal artery was observed without changes in venous flow velocity. After hemodilution in eyes affected by non-ischemic occlusion, a significant increase in maximal venous flow velocity only was noted. In branch retinal vein occlusion, no significant difference was observed in the RI between affected and unaffected eyes. After hemodilution, an improvement in RI was noted only for affected eyes.

CONCLUSIONS

The present results confirm the potential value of Doppler analysis in monitoring the impact of hemodilution on arterial and venous velocity in patients with central retinal vein occlusion.

Effect of isovolaemic haemodilution on visual outcome in branch retinal vein occlusion

AIMS

To assess the efficacy of isovolaemic haemodilution therapy (IHT) in the treatment of patients with branch retinal vein occlusion (BRVO).

METHODS

Patients presenting with BRVO between 1 July 1991 and 31 August 1993 were eligible for inclusion and randomised into treatment and control groups. Patients randomised to receive IHT were treated for 6 weeks with venesection and volume replacement using hydroxyethylstarch, a plasma expander. The target haematocrit was 35%. Follow up was for 1 year.

RESULTS

The baseline visual acuity of the two groups was similar at 0.74 and 0.75 logMAR units (Snellen 6/36), for the IHT and control groups, respectively. At 6 weeks, visual acuity in the IHT group had improved by 0.20 logMAR units (2 lines on the Bailey-Lovie chart) (p = 0.0001). Vision was unchanged in the control group. At 1 year, the IHT group exhibited an improvement of 0.43 logMAR units. By comparison, the improvement in the control group at 1 year was significantly less at 0.17 logMAR units (p = 0.03). The final visual acuity in the IHT and control groups was 0.30 (Snellen 6/12) and 0.60 (Snellen 6/24) logMAR units, respectively.

CONCLUSIONS

The results support the theory that IHT has a positive effect on the visual outcome in patients with BRVO.

A randomised prospective study of outpatient haemodilution for central retinal vein obstruction

PURPOSE

Central retinal vein obstruction (CRVO) has significant visual morbidity. We prospectively evaluated an outpatient haemodilution (HD) regimen for CRVO.

METHODS

We recruited 59 patients with CRVO of less than three months' duration and visual acuity (VA) worse than or equal to 6/9.5. Thirty patients underwent HD (packed cell volume of <0.35, 12 weeks); there were 29 controls and follow-up was for six months.

RESULTS

Incidence rates for VA improvement (P = 0.708) and rubeosis iridis (P = 0.619) between the two groups were not different. The incidence rate of VA deterioration was 5.315 times higher with HD (P = 0.035, Cox Proportional analysis).

CONCLUSION

This data does not support the previous studies on haemodilution.

Prognostic factors for retinal vein occlusion: prospective study of 175 cases

BACKGROUND

The prognosis of retinal vein occlusion is highly unpredictable because nonischemic types may convert into ischemic types within the first months. This study was designed to identify epidemiologic characteristics of the different types of retinal vein occlusion, their visual outcome, and their prognostic factors.

METHODS

The authors analyzed prospectively the data from patients who have had retinal vein occlusion with complete medical and biologic examination, including fluorescein angiography, and a 1-year follow-up.

RESULTS

One hundred seventy-five retinal vein occlusion eyes consisted of 120 central retinal vein occlusions (CRVO), 7 hemicentral occlusions, and 48 branch occlusions. In initially nonischemic CRVO eyes, retinal ischemia developed in 54%. The study of prognostic factors in the CRVO group showed that older age, male sex, and the number of risk factors (systemic vascular risk factors and glaucoma) were correlated with a poor visual outcome and with the development of retinal ischemia, as well as baseline visual acuity, initial extent of retinal ischemia, and rheologic findings (hematocrit, fibrinogen, and erythrocyte aggregation levels). Logistic regression underlined the prognostic role of sex, the number of risk factors, erythrocyte aggregation, and initial clinical features. Persistent macular edema was shown to be associated with hyperlipidemia and cardiovascular history, and inversely correlated to glaucoma.

CONCLUSION

Because clinical characteristics of CRVO may worsen, the authors' results provide a basis to predict visual outcome by taking into account epidemiologic and rheologic findings. A careful follow-up of these patients is recommended.

Elevated erythrocyte aggregation in patients with central retinal vein occlusion and without conventional risk factors

BACKGROUND

Retinal venous circulation is characterized by the combination of a low flow state and a high vascular resistance, which would make it particularly dependent on blood viscosity. Erythrocyte aggregation is the chief determinant of blood viscosity at low shear rates. Recent studies have demonstrated increased erythrocyte aggregation in many systemic vascular disorders and also in retinal vein occlusion.

METHODS

To assess the possible role of abnormal hemorheologic findings in the pathogenesis of central retinal vein occlusion (CRVO), the authors retrospectively studied erythrocyte aggregation and hematocrit and fibrinogen levels in 33 patients with CRVO and without any known risk factors (diabetes, hypertension, smoking, hyperlipidemia, cardiovascular disease, glaucoma). Erythrocyte aggregation was assessed with a light back-scattering method. Results were compared with those of a group of 33 age- and sex-matched controls.

RESULTS

Eleven (33%) of the 33 patients with CRVO had abnormal hemorheologic findings. Erythrocyte aggregation was highly significantly increased in the CRVO group when compared with the control group (P < 0.0001), as was the hematocrit level (P < 0.05). In addition, the proportion of patients with abnormal blood rheologic tests was greater (50%) in the subgroup of patients who initially had nonischemic CRVO that worsened into an ischemic CRVO during the follow-up.

CONCLUSION

These data suggest that abnormal hemorheologic findings could affect the pathogenesis of CRVO, and perhaps be predictive of an aggravation. The latter hypothesis needs to be confirmed in a larger, prospective study.

Hemodilution therapy in central retinal vein occlusion. One-year results of a prospective randomized study

Systemic hemorheologic abnormalities may play a part in the pathogenesis of central retinal vein occlusions. A statistically significant elevation of plasma viscosity was found in patients with acute central retinal vein occlusion compared with control patients. Local retinal blood flow parameters including arteriovenous passage time and mean arterial dye bolus velocity were significantly altered in the central retinal vein occlusion patients compared with age-matched controls at baseline examination. We performed a randomized, prospective, single-blind clinical investigation to determine the effect of hemorheological manipulation on the clinical course and retinal blood flow of eyes with central vein occlusion. Hemodilution included plasma expansion with hydroxyethyl-starch, withdrawal of whole blood if the hematocrit was above 42%, and rheologic manipulation with parenteral pentoxifylline. We found a statistically significant improvement in visual acuity at 1 year post-treatment for the treated group compared with the control group (increase of visual acuity of 1.5 lines vs decrease of 1.5 lines). The retinal blood flow parameters were markedly improved soon after the institution of therapy, and this may have contributed to the improvement in visual acuity in the treated group. There was no statistically significant difference between the two groups in the progression to ischemic central vein occlusion.

Central retinal vein occlusion in young adults

Central retinal vein occlusion (CRVO) is usually seen in older adults and is often associated with systemic vascular disease. CRVO can be seen in young adults, and although it is occasionally associated with a systemic disease, in the majority of cases it occurs in an otherwise healthy patient with no known systemic disease or ocular problem. Inflammation of the central retinal vein has been proposed as a cause of the occlusion in young adults and for that reason it has been called papillophlebitis. The appearance of unilateral optic disc edema, dilatation, and tortuosity of the major retinal veins with a variable amount of retinal hemorrhage in young, healthy adults with complaints of blurred vision or photopsias has been called, in addition to papillophlebitis, benign retinal vasculitis, optic disc vasculitis, nonischemic CRVO, big blind spot syndrome, and presumed phlebitis of the optic disc. An approach to the diagnostic evaluation of the young adult with CRVO is presented. Although most eyes recover vision to better than 20/40, about one-fifth have significant visual loss, and many suffer ocular sequelae. Many treatment modalities have been tried for this entity, but no conclusive evidence exists that any treatment alters its natural history.

Haemorheological parameters in patients with retinal artery occlusion and anterior ischaemic optic neuropathy

The haemorheological parameters haematocrit (Hct), plasma viscosity (PV), red cell aggregation (RCA), red cell filterability (RCF), apparent whole blood viscosity (WBV), and fibrinogen were measured in 31 patients with retinal artery occlusion (RAO), 25 patients with anterior ischaemic optic neuropathy (AION), and 19 patients with giant cell arteritis (GCA). The patient groups were compared with controls of same age and similar prevalence of cardiovascular risk factors. Patients with RAO and AION have a significantly decreased RCF in comparison with controls. All other parameters showed no differences. Patients with GCA had significantly decreased Hct and RCF and increased PV and fibrinogen. After 2 weeks of systemic treatment with high dose steroids in patients with GCA the plasma viscosity had returned to normal and was even lower than in controls, and the Hct and fibrinogen had reached normal levels.

Haemorheological changes in patients with retinal vein occlusion after isovolaemic haemodilution

In 83 patients with central retinal vein occlusion and branch vein occlusion we measured the haematocrit (HCT), plasma viscosity (PV), red cell aggregation (RCA), red cell filterability (RCF) and apparent whole blood viscosity (WBV). A control group (n = 41) was matched for sex, age, and cardiovascular risk factors. Measurements were performed before and after treatment with isovolaemic haemodilution (IHD). We found no significant differences between patients with retinal vein occlusion (RVO) and control subjects in haematocrit, plasma viscosity, red cell aggregation, and red cell filterability and no increased whole blood viscosity in the patient group. Patients with ischaemic retinal vein occlusion and non-ischaemic retinal vein occlusion did not show different haemorheological parameters either. After treatment with haemodilution, only the haematocrit and whole blood viscosity were significantly decreased, and there were no changes in plasma viscosity, red cell aggregation or red cell filterability.