Central Retinal Vein Obstruction Research Articles

Retinal vessel analysis in vascular occlusions of the eye

Aims/Purpose: This cohort study investigates how the static and dynamic vessel parameters differ in patients with vascular occlusions and if there are any variations between the different types of vessel occlusion.Methods: Patients with the diagnosis of branch retinal artery obstruction BRAO, central retinal artery obstruction CRAO, branch retinal vein obstruction BRVO, central retinal vein obstruction CRVO, anterior ischaemic optic neuropathy AION and any combination of these Combo were included in our study. During their inpatient stay for cardiovascular diagnostics all patients were examined via static and dynamic vessel analysis (IMEDOS Health GmbH, Jena) to obtain the arteriovenous ratio (AVR), the central retinal artery equivalent (CRAE), the central retinal vein equivalent (CRVE) and the flicker light induced dilation of the retinal arteries (FLA) and veins (FLV). The vessel density was determined via OCT angiography (Heidelberg Engineering GmbH, Heidelberg).Results: 34 patients (70% male; 30% female; mean age 69.6 ± 11.3 years) with 9 (26.5%) CRVO, 8 (23.5%) AION, 5 (14.7%) BRAO and 4 (11.8%) CRAO, BRVO and Combo each have been included. The best visual acuity (BCVA) of the diseased eye differed significantly between the groups (AION 0.41 ± 0.61, CRAO 2.40 ± 0.20, BRAO 0.16 ± 0.05, CRVO 0.81 ± 0.86, BRVO 0.18 ± 0.10, Combo 1.53 ± 0.68; p < 0.001) whereas the BCVA of the healthy eyes were comparable. The CRVE showed a significant difference between the groups CRAO – CRVO (p = 0.008), CRAO – Combo (p < 0.001) and BRAO–Combo (p = 0.026). The FLV of the diseased eye was significantly higher in patients with AION than in the CRAO group (p = 0.049). The parameters of the static vessel analysis of the healthy eyes were comparable.Conclusions: Preliminary analysis shows significant differences of individual parameters of the retinal vessel analysis between different types of vascular occlusion. The diagnostic and research benefit for the individual patient remains to be further evaluated.

Combined Branch Retinal Artery and Central Retinal Vein Occlusion: A Systematic Review.

We performed a systematic review and analyzed the current available data on branch retinal artery occlusion (BRAO) with simultaneous central retinal vein obstruction (CRVO), a rarely described occurrence. MEDLINE/PubMed and ISI Web of Sciences searches were performed according to MOOSE guidelines. Studies were considered eligible if they (1) described patients with simultaneous BRAO + CRVO and (2) had been published in peer-reviewed journals. We initially identified 239 records from databases. Ultimately, only 19 reports met the selection criteria. Twenty-nine patients (15 men, 14 women; mean age 43 ± 15 years) were analyzed. Seventeen (59%) patients presented vascular risk factors. Mean visual acuity at onset and final visual outcome were 20/83 and 20/45, respectively, an insignificant improvement. Vision improved in 48% of cases. A marked heterogeneity in treatment approach was found. Eight (28%) patients received no therapy, whereas for 21 (72%) a large variety of topical and/or systemic drugs was given. In the treated group, mean visual acuity at onset and final visual outcome were 20/90 and 20/44, respectively, a not statistically significant improvement. Results suggest that combined BRAO + CRVO occurs at a younger age than isolated BRAO or CRVO. At present, there is insufficient evidence to support any specific management to improve vision in simultaneous BRAO + CRVO.

Effect of Intravitreal Triamcinolone (IVT) Injection on Visual Acuity in Patients with Ischemic CRVO

Aim: To govern the intravitreal injection effect of triamcinolone (IVT) on visual acuity in patients with ischemic central retinal vein obstruction (CRVO). Study Design: A randomized clinical trial. Methods:The patients with ischemic event of CRVO less than amonth who were referred to the ophthalmology departmentof Hayatabad Medical Complex, Peshawar and Woman Medical and Dental College, Abbottabad. Patents were included for the duration from March 2021 to August 2021.Inclusion criteria were: < one month duration of CRVO, normal intraocular pressure, no symptoms of hypertensive or diabetic retinopathy, history of eye surgery or laser therapy, and no vascular disease. Patients were randomized into 2 groups: control group (no injection) and intervention group (0.1 cc IVT injection). Follow-up is scheduled for 1, 2, 3 and 6 months after injection for all patients. The main outcomes of the study were evaluated and used for statistical analysis were SPSS software version 21.0 ion test-t statistical test. Results:70 patients (36 men and 34 women) participated in the study. 62.1 ± 8.9 was the mean age of patients (range: 30-80). The time of symptoms was 20 ± 4.9 days in the control group and in the IVT group; duration was 19 ± 6 days (p = 0.65). All subjects had symptoms of ischemic CRVO. The IVT group has mean baseline visual acuity of 1.80 ± 0.19 logMAR and in the control group; it was 1.91 ± 0.08 logMAR (p = 0.1). The enhancement in VA in the IVT group was better after one month as compared to the control group (p = 0.018); though, this variance was not significant in other control studies. Also, before and after injection; the alteration in IOP was not significant (p = 0.802). Conclusions: This analysisexhibited that triamcinolone intravitreal injection had no substantial long-term outcome on visual acuity among CRVO patients. Keywords:Triamcinolone, Central Retinal Vein Occlusion

Review of intravitreal VEGF inhibitor toxicity and report of collapsing FSGS with TMA in a patient with age-related macular degeneration.

Intravitreal vascular endothelial growth factor (VEGF) receptor blockade is used for a variety of retinal pathologies. These include age-related macular degeneration (AMD), diabetic macular edema (DME) and central retinal vein obstruction. Reports of absorption of intravitreal agents into systemic circulation have increased in number and confirmation of depletion of VEGF has been confirmed. Increasingly there are studies and case reports showing worsening hypertension, proteinuria, renal dysfunction and glomerular disease. The pathognomonic findings of systemic VEGF blockade, thrombotic microangiopathies (TMAs), are also being increasingly reported. One lesion that occurs in conjunction with TMAs that has been described is collapsing focal segmental glomerulosclerosis (cFSGS). cFSGS has been postulated to occur due to TMA-induced chronic glomerular hypoxia. In this updated review we discuss the mechanistic, pharmacological, epidemiological and clinical evidence of intravitreal VEGF toxicity. We review cases of biopsy-proven toxicity presented by our group and other investigators. We also present the third reported case of cFSGS in the setting of intravitreal VEGF blockade with a chronic TMA component that was crucially found on biopsy. This patient is a 74-year-old nondiabetic male receiving aflibercept for AMD. Of the two prior cases of cFSGS in the setting of VEGF blockade, one had AMD and the other had DME. This case solidifies the finding of cFSGS and its association with chronic TMA as a lesion that may be frequently encountered in patients receiving intravitreal VEGF inhibitors.

Pathogenesis of Central Retinal Vein Obstruction and Macular Edema

Central retinal vein occlusion (CRVO) is a common retinal vascular disorder. However, the exact pathogenesis of CRVO is not known. Various local and systemic factors play a role in the CRVO. CRVO might cause visual morbidity, including macular edema (ME) and neovascularization. ME occurs when fluid and protein deposits accumulate in the macular region. The pathophysiology of ME is complex, with a variety of processes involved in its development. The pathogenesis of CRVO and ME is discussed in the current review.

Efficacy of panretinal laser in ischemic central retinal vein occlusion: A systematic review.

The aim of the present systematic review was to assess the efficacy of laser therapy for ischemic central retinal vein occlusion (CRVO). Relevant studies were retrieved by searching the PubMed, Embase, Chinese Biomedical Literature Database and, Chinese Science and Technology Periodicals databases using a combination of key words, including 'central retinal vein obstruction', 'CRVO', 'laser' and 'panretinal photocoagulation'. The titles, abstracts and full texts were screened by two independent reviewers and studies were selected according to specific inclusion criteria. Data were extracted and the quality of each study was graded using the Grading of Recommendations, Assessment, Development and Evaluation or Methodological Index for Non-Randomized Studies (MINORS) criteria. A total of 1,187 abstracts were retrieved, and finally, 11 clinical studies were selected, including 534 cases of CRVO. Of these, 8 studies compared the efficacy of laser therapy with other treatments for CRVO, two studies compared the efficacy of laser therapy and drug treatment for CRVO and one study compared the efficacy of early laser therapy with standard laser therapy (regular examinations and laser therapy performed as soon as neovascularization was identified) for CRVO. Among them, the results of five studies demonstrated that panretinal photocoagulation (PRP) for the prevention of iris neovascularization and neovascular glaucoma is inefficient regarding the improvement of visual acuity. A total of 10 studies indicated that laser therapy achieved better outcomes in neovascularization of the retina, optic disc neovascularization and iris neovascularization, neovascular glaucoma, vitreous hemorrhage, changes in the visual field, macular edema, macular thickness and intraocular pressure. Of note, it was indicated that laser photocoagulation prevents the severe vascular complications of CRVO. In addition, in the eyes of patients receiving PRP for the treatment of ischemic CRVO, significant reductions in corneal sub-basal nerve plexus parameters and average peripapillary retinal nerve fiber layer thickness were observed. Furthermore, laser photocoagulation was able to increase retinal blood flow in eyes with ischemic CRVO.

En Face Optical Coherence Tomography Analysis to Assess the Spectrum of Perivenular Ischemia and Paracentral Acute Middle Maculopathy in Retinal Vein Occlusion

To assess the spectrum of perivenular ischemia in eyes with retinal vascular obstruction (typically central or hemicentral retinal vein obstruction) using en face optical coherence tomography (OCT). Retrospective observational case series. Eyes with recent retinal vascular occlusion illustrating paracentral acute middle maculopathy (PAMM) in a perivenular fern-like pattern with en face OCT were evaluated in this study. Multimodal retinal imaging including en face OCT segmentation of the inner nuclear layer was performed in all patients. Color fundus photography and fluorescein angiography (FA) images were used to create a vascular overlay of the retinal veins vs the retinal arteries to map the distribution of PAMM with en face OCT analysis. Multimodal retinal imaging was performed in 11 eyes with acute retinal vascular obstruction. While 7 eyes demonstrated obvious findings of retinal vein obstruction (5 with central and 2 with hemicentral retinalvein occlusion), 4 eyes were unremarkable at presentation. En face OCT analysis demonstrated a spectrum of perivenular PAMM illustrating a fern-like pattern with sparing of the periarteriolar area in all cases. En face OCT may illustrate a remarkable perivenular pattern of PAMM in eyes with retinal vascular obstruction even in the absence of significant funduscopic findings. Perivenular PAMM with en face OCT demonstrates a wide spectrum of variation with narrow fern-like perivenular lesions at the mildest end and more diffuse lesions with only periarterial sparing at the most severe end of the spectrum. Arterial hypoperfusion secondary to outflow obstruction from a central retinal vein obstruction appears to be the most common cause of this presentation, although primary arterial hypoperfusion may also be an etiology.

A Case of Anterior Migration of Fragmented Dexamethasone Intravitreal Implant

Purpose: To report a case of fragmentation and anterior migration occurred after dexamethasone intravitreal implant (Ozurdex, Allergan, Irvine, CA, USA) injection in a branch retinal vein occlusion patient. Case summary: A 66-year-old male was referred for blurred vision. He received cataract surgery in 1986 and was diagnosed with central retinal vein obstruction in 2011 in the right eye. For treatment of macular edema, dexamethasone intravitreal implant was performed in the right eye. One week after implantation, a fragment of the dexamethasone implant migrated to the anterior chamber with corneal edema and surgical removal was performed immediately. One day after removal, the remaining fragmented implant migrated to the anterior chamber and corneal edema still existed. The fragmented implant was removed with anterior chamber irrigation. After removal, corneal edema improved and visual acuity was recovered. Conclusions: Anterior migrated dexamethasone implant could induce corneal complications, such as corneal edema and corneal decompensation and might lower the corneal endothelial cell even if immediately removed. We report a case of corneal edema, which was induced by anterior migration of a fragmented dexamethasone implant and recovered with immediate surgical removal. J Korean Ophthalmol Soc 2016;57(4):667-671

Genetic polymorphisms and their association with central retinal vein occlusion combined with cilioretinal artery occlusion

Combined cilioretinal artery and retinal vein occlusions are infrequently documented retinal vascular disorders. The role of genetic polymorphisms has been investigated. A 45-year-old woman presented with decreased visual acuity in her right eye. Fluorescein angiography demonstrated a cilioretinal artery occlusion associated with central retinal vein obstruction. Results of testing for the factor V Leiden were negative. However, the patient was heterozygous for the prothrombin G20210A mutation and the two polymorphisms (C667T and A1298C) of the methylenetetrahydrofolate reductase (MTHFR) gene. Specific genetic factors can be associated with retinal vascular occlusions.

Responce to intravitreal Bevacizumab for macular edema following central retinal vein occlusion in patients with pseudoexfoliation syndrome

AbstractPurpose To evaluate efficacy of intravitreal 1.25mg Bevacizumab in patients with pseudoexfoliation sindrome (PEX) and macular edema (ME) secondary to central or branch retinal vein occlusion.Methods A retrospective study was performed on 168 patients with central retinal vein occlusion (CRVO) and branch retinal vein obstruction (BRVO) with significant decreased visual acuity (VA) due to ME. To evaluate the role of 1.25mg bevacizumab in patients with PEX, were created two groups: the first group – 21 patients with CRVO or BRVO and clinical diagnosis of PEX (mean age 74.5 [range 63 ‐ 87]) and the second group – 21 patients with CRVO or BRVO with no clinical signs of PEX (mean age 72.7 [range 60 ‐85]). All patients were analyzed for the best corected VA and optical coherence tomography changes of the central macular thickness.Results A clinical diagnosis of PEX was present in 21 of 168 patients (12.5%), 17 (81.0%) of them had a CRVO and 4 (19.1%) – BRVO. The average of initial VA in the first group was 0.16 (SD±0.19), in the second group – 0.18 (SD±0.19). In the second group the VA after intravitreal injection of bevacizumab was significantly better (0.49 (SD±0.33)) compared to the first group (0.29 (SD±0.26)) (Mann‐Whitney test, p=0.043). Mean central retinal thickness decreased from 696.9µm (SD±261.9) to 261.0µm (SD±154.2) in the first group and 636.5µm (SD±236.9) to 254.5µm (SD±167.2) in the second group.Conclusion Pseudoexfoliation syndrome is significantly more common in eyes with central retinal vein occlusion compared to branch retinal vein occlusion. Pseudoexfoliation syndrome could be counted as one of the factors damaging functioning of the neurosensory retina.

Clinical Course after Intravitreal Bevacizumab Injection in Ischemic Central Retinal Vein Obstruction

Clinical Course after Intravitreal Bevacizumab Injection in Ischemic Central Retinal Vein Obstruction

Massive Exophthalmos after Traumatic Carotid-Cavernous Fistula Embolization

An 18-year-old man without previous clinical problems developed a left traumatic carotid-cavernous fistula after a traffic accident. An endovascular embolization with coils was performed without success. The drainage was derived to the superior ophthalmic vein solely and clinical worsening occurred. Left eye proptosis, chemosis and intraocular pressure increased. Complete ophthalmoplegia developed and visual acuity decreased due to a central retinal vein obstruction. After a second embolization attempt the fistula was closed successfully but proptosis, chemosis and intraocular pressure remained uncontrolled despite medical treatment. Therefore an orbital decompression surgery was performed. Ophthalmoplegia, proptosis and chemosis improved and intraocular pressure was controlled.Although retinal hemorrhages persist, no neovascularization has developed. Central retinal vein occlusion in young patients seems to have a different etiology than in the elderly. In young patients, local factors are more frequently identified than systemic vascular diseases. Early detection of central retinal vein obstruction may prevent deterioration of visual acuity.

INTRAVITREAL TRIAMCINOLONE ACETONIDE FOR ACUTE RADIATION PAPILLOPATHY

To evaluate intravitreal triamcinolone acetonide for patients with visually symptomatic acute radiation-induced papillopathy. In a prospective, nonrandomized, single-center case series, intravitreal triamcinolone acetonide (4 mg/0.1 mL) was injected through the pars plana using sterile technique in 9 patients with radiation papillopathy after plaque radiotherapy for choroidal melanoma. Status of radiation papillopathy and final visual acuity were the main outcome measures. At the time of diagnosis of the choroidal melanoma, visual acuity was 20/20 to 20/40 (n = 6), 20/60 (n = 2), and 20/100 (n = 1). The mean radiation dose to the optic disk was 6,175 cGy (median, 5,994 cGy; range, 3,571-12,760 cGy). Radiation papillopathy developed a mean of 18 months (median, 17 months; range, 6-33 months) after plaque radiotherapy. In all cases, the choroidal melanoma was regressed, and there was no retinal detachment or neovascularization of the retina, optic disk, or iris. Concomitant radiation maculopathy was found in 8 eyes manifesting as macular edema (n = 8), intraretinal dot hemorrhages (n = 6), intraretinal exudation (n = 6), or nerve fiber layer infarction (n = 3). The radiation papillopathy findings included optic disk hyperemia (n = 9), edema (n = 9), and circumpapillary hemorrhage (n = 8). At the time of diagnosis of radiation papillopathy, visual acuity was 20/70 (n = 1), 20/100 (n = 4), 20/200 (n = 1), and counting fingers (n = 3). At 1 week after injection of triamcinolone acetonide, visual acuity improvement was found in seven patients, and resolution of optic disk hyperemia and edema was noted for four and three patients, respectively. At a mean follow-up of 11 months (median, 9 months; range, 6-19 months), visual acuity was stable or improved in 7 patients, and resolution of optic disk hyperemia and edema was found in all 9 patients. The mean time to improvement in visual acuity by > or =2 lines was 3 weeks (median, 1 week; range, 1-12 weeks). The mean time to complete resolution of radiation papillopathy was 4 months. The two patients with worse final visual acuity also had macular hole and central retinal vein obstruction. The only complication of this therapy was possibly related cataract in three patients. During short-term follow-up, acute radiation-induced papillopathy appears to respond rapidly to intravitreal triamcinolone acetonide injection with resolution of optic disk hyperemia and edema and modest return of visual acuity. The long-term effects remain unknown.

Clinical Case Notes

Three cases are reported where life-threatening haematological disorders requiring urgent medical intervention presented initially to the ophthalmologist. Case one, chronic myeloid leukaemia, presented with bilateral leukaemic retinopathy and central retinal vein obstruction due to hyperviscosity. Case two, acute myeloid leukaemia, presented with bilateral haemorrhagic retinopathy. Case three, aplastic anaemia, presented with bilateral retinopathy due to anaemia and thrombocytopaenia resembling bilateral central retinal vein occlusion. In all three cases the presence of simultaneous bilateral retinal vascular involvement and white-centred haemorrhages suggested an underlying haematological disorder and differentiated them from typical retinal venous obstruction. Prompt identification of the underlying haematological disorder allows timely referral for potentially life-saving treatment.

Laser therapy for central retinal vein obstruction.

The Collaborative Central Retinal Vein Occlusion Study has recently reported information on the early natural history of central vein occlusion that includes a 16% conversion of perfusion to nonperfusion within the first 4 months. The Collaborative Central Vein Occlusion Study randomized trial of laser photocoagulation for macular edema and for the management of iris neovascularization suggested that grid laser photocoagulation is not useful for the improvement of visual acuity that is decreased because of perfused macular edema and that iris neovascularization is best managed by applying panretinal photocoagulation after the first appearance of iris neovascularization. A recent report has suggested that chorioretinal venous anastomosis can be achieved in some patients with vein occlusion to permit venous outflow through the choroid, lessen the likelihood of progression to ischemia, and improve visual acuity by lessening macular edema.

Correlation of electroretinographic and fluorescein angiographic findings in unilateral central retinal vein obstruction

In central retinal vein obstruction (CRVO), electroretinogram (ERG) abnormalities and extensive retinal capillary dropout (CD) in the fluorescein angiogram (FA) are good indicators of retinal ischemia. We retrospectively studied patients with unilateral CRVO and compared the ERG and FA results. Single white flash ERG, photopic ERG, scotopic ERG and flicker ERG were recorded in 30 cases of unilateral CRVO. We analyzed the correlation between the ERG results and the presence/absence of extensive CD. The ERG b/a-wave amplitude ratios, photopic and scotopic b-wave amplitudes, and flicker amplitudes were significantly smaller (P < 0.05) in eyes with extensive CD (n = 12, 40%), than in eyes without (n = 18, 60%). When the photopic or scotopic b-wave amplitudes were normal or supernormal, extensive CD on FA was absent in all eyes. When the b/a-wave ratios were > or = 1.0 or when the b-wave amplitudes with white flash or flicker amplitudes were normal or supernormal, extensive CD was present in less than 32% of eyes. These results suggest that the ERG results, especially the b/a-wave amplitude ratio, are significantly correlated with the presence/absence of CD on FA in CRVO.

Electroretinogram b/a wave ratio improvement in central retinal vein obstruction.

The electroretinogram (ERG), especially the b/a wave ratio, is considered a good indicator of retinal ischaemia in central retinal vein obstruction (CRVO). Seven CRVO patients who showed b/a wave ratio improvement from < 1.0 [negative type (-) ERG] to > or = 1.0 and one from 1.07 to 1.53 were studied. Three mechanisms of change were observed: firstly, the b-wave amplitude increased without an a-wave amplitude decrease (group A, n = 2); secondly, the b-wave amplitude increased with an a-wave amplitude decrease (group B, n = 4); and, thirdly, both decreased, but the a-wave amplitude decreased more markedly (group C, n = 2). In group A, the visual acuities improved markedly. In group B, the visual acuities improved in two cases in which the b-wave amplitude reached the normal range; the visual acuities did not improve in two cases in which the b-wave amplitude did not reach the normal range. In group C, the visual acuities remained poor. The negative (-) ERG or significantly reduced b/a wave ratio is associated with ischaemic CRVO and did not occur because of the filtering effect of the haemorrhage, which may reduce the stimulus light for the ERG. Improvement of the reduced b/a wave ratio with an increased b-wave amplitude was accompanied by improvements in fundus appearance and visual acuity in CRVO. The results suggest that the retinal ischaemia in CRVO, as revealed by the ERG and fluorescein angiogram, may be reversible in some cases.

Prognostic value of initial electroretinogram in central retinal vein obstruction

We retrospectively studied the correlation between the initial electroretinogram (ERG) recordings and the final visual acuities (VA) of 47 patients with central retinal vein obstruction (CRVO) after follow-up of more than 1 year. The a- and b-wave amplitudes and the b/a ratio with white flash were significantly larger in patients with good vision (VA > 20/200) than in those with poor vision (VA < or = 20/200). The b/a ratio and b-wave amplitude with white flash showed sensitivity and specificity of more than 78% for visual prognosis. The latest VA was < or = 20/200 in all 20 patients with a subnormal b-wave amplitude and in all 15 with b/a ratio < 1.05. These results suggest that the ERG recorded soon after (CRVO) onset correlates strongly with visual prognosis.

BLOOD LEVELS IN MACULAR CYSTOID SPACES AND THEIR RELATIONSHIP TO RETINAL VEIN OBSTRUCTION

Blood levels in macular cystoid spaces are commonly seen in patients with branch or central retinal vein obstruction, but have not been previously reported. To determine blood levels in cystoid spaces, a retrospective study was conducted of 102 eyes with branch retinal vein obstruction, 54 eyes with central retinal vein obstruction, 207 eyes with clinically significant diabetic macular edema, and 109 eyes with aphakic or pseudophakic cystoid macular edema seen over a 5-year period. Definite blood levels in cystoid spaces were found in 26 eyes (25%) with branch vein obstruction and in 4 eyes (8%) with central vein obstruction. In contrast, this clinical change was detected in only 1 of 207 eyes (1%) with diabetic cystoid macular edema, and in only 2 of 109 eyes (2%) with aphakic or pseudophakic cystoid macular edema (P < 0.001). When blood levels in cystoid spaces were detected in patients with branch vein obstruction, the site of obstruction tended to be superotemporal (P < 0.05). Blood levels in cystoid spaces are an important sign of retinal vein obstruction, and may help establish the diagnosis in certain cases.

Combined central retinal artery-central vein obstruction

The cases of 23 patients with unilateral combined central retinal artery-central retinal vein obstruction are described. Criteria for the abnormality included: a history of relatively sudden visual loss; superficial retinal whitening in the posterior pole in combination with a cherry spot; and intraretinal blood, generally associated with dilated and/or tortuous retinal veins. In five instances (22%) the obstructions developed after retrobulbar injection. Among the 21 patients with followup for at least 6 months, or until the onset of neovascularization of the iris, 17 (81%) developed rubeosis iridis. Late histopathology was obtained in two eyes. Hemorrhagic necrosis of the retina was observed in some areas of the posterior pole and attenuation of the inner retinal layers, similar to that seen with late central retinal artery obstruction, was noted elsewhere. Periphlebitis of the central retinal vein within the optic nerve was found in each case.