1.5 Summary of Key Points

When lumping is done, most lump HCRVO with CRVO since the pathophysiology is similar.110,111 Other studies however have lumped HCRVO with BRVO.112 For the most part, the pathoanatomy of HCRVO is considered to be identical to that of CRVO with the modiÞcation that one or two of the hemicentral veins can be occluded. When two are occluded, the loci of the occlusions may be at different distances posterior to the lamina cribrosa. Thus, it is possible to have a clinical situation where both HCRVs are occluded, but one is occluded more anteriorly, with greater retinal ischemia, and one is occluded more posteriorly, leading to a nonischemic hemicentral vein occlusion in half of the fundus.80

1.5 Summary of Key Points

¥RVOs have multiple predisposing and precipitating factors, and in any given case, the contributing factors may differ.

¥Eyes with RVOs are on average slightly shorter than eyes without RVO.

¥The layers seen in spectral domain optical coherence tomographic images correlate well

with retinal histologic layers.

¥The inner-segment/outer-segment junction is an important optical coherence tomographic landmark with prognostic importance in RVOs.

¥The inner and outer nuclear layers are bottlenecks for molecular diffusion across the retina.

¥Cotton wool spots represent axoplasmic ßow stasis in ganglion cell axons due to focal ischemia.

¥The bloodÐretina barrier is composed of zonula occludens junctions between retinal pigment epithelial cells and vascular endothelial cells.

¥Among the vitreous functions, the ones most relevant to RVOs are loculation of cytokines that inßuence vasopermeability, slowing of convection currents of oxygenated aqueous from the ciliary body, and provision of a scaffold for angiogenesis.

¥The staircase of retinal vascular luminal diameters is

ÐCentral retinal artery (170 m)

ÐBranch retinal arteries (120 m)

ÐPeripheral arterioles (15 m)

ÐCapillaries (5 m)

ÐTerminal venules (20 m)

ÐBranch retinal veins (180 m)

ÐCentral retinal vein (200 m)

¥Hemicentral retinal veins are found in 20% of eyes.

¥There are normal, hemodynamically unimportant anastomoses between terminal venules of adjacent retinal sectors, but not between arterioles of adjacent sectors. The venular anastomoses dilate in BRVO and HCRVO.

¥There are normal, hemodynamically unimportant anastomoses between terminal venules at the optic disc and the choroid. These dilate with CRVO or HCRVO.

¥The central retinal vein narrows at the lamina cribrosa.

¥The central retinal artery and vein are enclosed by a common, indistensible Þbrous sheath thought to be important in the pathogenesis of CRVO and HCRVO.

¥At the intraretinal crossing of a branch retinal artery and vein, the two are enclosed by a common, indistensible Þbrous sheath thought to be important in the pathogenesis of BRVO.

¥CRVO is thought to arise from thrombosis of the central retinal vein at variable distances posterior to the lamina cribrosa. The thought is that the more anterior the clot, the more ischemic the occlusion due to the relative absence of collaterals for drainage of venous blood to the choroid.

¥BRVO is thought to arise from thrombosis at the branch retinal vein where it is overcrossed by a sclerotic artery.

References

1. Hayreh SS, Zimmerman B, McCarthy MJ, Podhajsky P. Systemic diseases associated with various types of retinal vein occlusion. Am J Ophthalmol. 2001;131:61Ð77.

2. Weger M, Renner W, Steinbrugger I, et al. Role of thrombophilic gene polymorphisms in branch retinal vein occlusion. Ophthalmology. 2005;112:1910Ð5.

3. Ariturk N, Oge Y, Erkan D, et al. Relation between retinal vein occlusions and axial length. Br J Ophthalmol. 1996;80:633Ð6.

4. Timmerman E, Renardel de Lavalette V, Van Den Brom H. Axial length as a risk factor to branch retinal vein occlusion. Retina. 1997;17:196Ð9.

5. Simons B, Brucker A. Branch retinal vein occlusion: axial length and other risk factors. Retina. 1997;17:191Ð5.

6. Goldstein M, Leibovitch I, Varssano D, et al. Axial length, refractive error, and keratometry in patients

with branch retinal vein occlusion. Eur J Ophthalmol. 2004;14:37Ð9.

7.Mehdizadeh M, Ghassemifar V, Ashraf H, Mehryar M. Relationship between retinal vein occlusion and axial length of the eye. Asian J Ophthalmol. 2005;7:

146Ð8.

8. Talu S, Stefanut C. Axial length and branch retinal vein occlusion. Oftalmologia. 2004;48:81Ð4.

9. Tsai SC, Chen HY, Chen CY. Relationship between retinal vein occlusion and axial length. Kaohsiung J Med Sci. 2003;19:453Ð7.

10.Menke MN, Feke GT, McMeel JW, et al. Hyperviscosity-related retinopathy in waldenstrom macroglobulinemia. Arch Ophthalmol. 2006;124: 1601Ð6.

11.Hogan MJ, Alvarado JA, Weddell JE. Retina. In: Histology of the human eye: an atlas and textbook. Philadelphia: Saunders; 1971; Chap. 9.

12.Gass JDM. Stereoscopic atlas of macular diseases diagnosis and treatment, vol. 1. 4th ed. St. Louis: Mosby-Year Book, Inc; 1997. p. 1Ð599.

13.Jonas JB, Nguyen NX, Naumann GO. The retinal nerve Þber layer in normal eyes. Ophthalmology. 1989;96:627Ð32.

14. Kaufman PL, Alm A. AdlerÕs physiology of the eye. 10th ed. St. Louis: Mosby; 2003. p. 309Ð10.

15. Penfold PL, Wen L, Madigan MC, et al. Triamcinolone acetonide modulates permeability and intercellular adhesion molecule-1 (ICAM-1) expression of the ECV304 cell line: implications for macular degeneration. Clin Exp Immunol. 2000;121:458Ð65.

16.Hageman GS, Kuehn MH. Biology of the interphotoreceptor matrix-retinal pigment epithelium-retina interface. In: The retinal pigment epithelium. Oxford:

Oxford University Press; 1998; chap. 18.

17. Tao Y, Li XX, Jiang YR, et al. Diffusion of macromolecule through retina after experimental branch retinal vein occlusion and estimate of intraretinal barrier. Curr Drug Metab. 2007;8:151Ð6.

18.Gomez ML, Mojana F, Bartsch DU, Freeman WR. Imaging of long-term retinal damage after resolved cotton wool spots. Ophthalmology. 2009;116:2407Ð14.

19. Mcleod D. Why cotton wool spots should not be regarded as retinal nerve Þber layer infarcts. Br J Ophthalmol. 2005;89:229Ð37.

20. Lasansky A, Wald F. The extracellular space in the toad retina as deÞned by the distribution of ferrocyanide: A light and electron microscope study. J Cell Biol. 1962;15:463Ð79.

21.Peyman GA, Spitznas M, Straatsma BR. Peroxide diffusion in the normal and photocoagulated retina. Invest Ophthalmol Vis Sci. 1971;10:181Ð9.

22.Dowling JE. The retina: an approachable part of the brain. Cambridge: Belknap and Harvard; 1987. p. 1Ð282.

23.Danis RP, Wallow IH. HRP/trypsin technique for

studies of the retinal vasculature. Invest Ophthalmol Vis Sci. 1986;27:434Ð7.

24. Hirano A, Becker NH, Zimmerman HM. The use of peroxidase as a tracer in studies of alterations in the blood-brain barrier. J Neurol Sci. 1970;10:205Ð13.

25.Nguyen NX, Knchle M. Aqueous ßare and cells in eyes with retinal vein occlusion Ð correlation with retinal ßuorescein angiographic Þndings. Br J Ophthalmol. 1993;77:280Ð3.

26.Miyake K, Miyake T, Kayazawa F. Blood-aqueous barrier in eyes with retinal vein occlusion. Ophthalmology. 1992;99:906Ð10.

27. Kamei M, Misono K, Lewis H. A study of the ability of tissue plasminogen activator to diffuse into the subretinal space after intravitreal injection in rabbits. Am J Ophthalmol. 1999;128:739Ð46.

28.Ghazi NG, Noureddine BN, Haddad RS, et al. Intravitreal tissue plasminogen activator in the management of central retinal vein occlusion. Retina.

2003;23:780Ð4.

29. Kado M, Trempe CL. Role of the vitreous in branch retinal vein occlusion. Am J Ophthalmol. 1988;105: 20Ð4.

30. Hikichi T, Konno S, Trempe CL. Role of the vitreous in central retinal vein occlusion. Retina. 1995;15: 29Ð33.

31. Sakuma T, Mizota A, Inoue J, Tanaka M. Intravitreal injection of autologous plasmin enzyme for macular edema associated with branch retinal vein occlusion. Am J Ophthalmol. 2010;150:876Ð82.

32.Udaondo P, Diaz-Lopis M, Garcia-Delpech S, et al. Intravitreal plasmin without vitrectomy for macular edema secondary to branch retinal vein occlusion. Arch Ophthalmol. 2011;129:283Ð7.

33.Johnson TM, Vaughn CW, Glaser BM. Branch retinal vein occlusion associated with vitreoretinal traction. Can J Ophthalmol. 2006;41:600Ð2.

34.Gariano RF, Kalina RE, Hendrickson AE. Normal and pathological mechanisms in retinal vascular development. Surv Ophthalmol. 1996;40:481Ð90.

35.Singh S, Dass R. The central artery of the retina I. Origin and course. Br J Ophthalmol. 1960;44:193Ð212.

36.Rene C. Update on orbital anatomy. Eye. 2006;20: 1119Ð29.

37. Ettl A, Zwrtek K, Daxer A, Salomonowitz E. Anatomy of the optical apex and cavernous sinus on high-reso- lution magnetic resonance images. Surv Ophthalmol. 2000;44:303Ð23.

38.Williamson TH, Lowe GD, Baxter GM. Inßuence of age, systemic blood pressure, smoking, and blood viscosity on orbital blood velocities. Br J Ophthalmol.

1995;79:17Ð22.

39. Schatz H, Fong ACO, McDonald HR, et al. Cilioretinal artery occlusion in young adults with central retinal vein occlusion. Ophthalmology. 1991;98:594Ð601.

40.McLeod D. Central retinal vein occlusion with cilioretinal infarction from branch ßow exclusion and choroidal arterial steal. Retina. 2009;29:1381Ð95.

41.Hayreh SS. Posterior ciliary artery circulation in health and disease: the Weisenfeld lecture. Invest Ophthalmol Vis Sci. 2004;45:749Ð57.

42.Harris A, Jonescu-Cuypers CP, Kagemann L, et al. Atlas of ocular blood ßow: vascular anatomy, pathophysiology, and metabolism. Philadelphia: Butterworth Heinemann; 2003. p. 1Ð128.

43. Sigelman J, Ozanics V. Retina. In: Duane TD, Jaeger EA, editors. Biomedical foundations of ophthalmology. Philadelphia: Harper & Row Publishers; 1983; chap. 19.

44. Hayreh SS. Occlusion of the central retinal vessels. Br J Ophthalmol. 1965;49:626Ð45.

45. Hayreh SS. Blood supply of the optic nerve head and its role in the optic atrophy, glaucoma, and oedema of the optic disc. Br J Ophthalmol. 1969;53:721Ð48.

46. Ko MY, Kim DS, Ahn YK. Peripapillary circle of Zinn-Haller revealed by fundus ßuorescein angiography. Br J Ophthalmol. 1997;81:663Ð7.

47.Hayreh SS. Radial optic neurotomy for nonischemic central retinal vein occlusion. Arch Ophthalmol. 2004;122:1572Ð3.

48.Williamson TH, Barr DB, Baxter GM. Understanding of the retinal circulation provided by an anomalous retinal vein. Br J Ophthalmol. 1994;78:798Ð9.

49.Singh S, Dass R. The central artery of the retina II. A

study of its distribution and anastomoses. Br J Ophthalmol. 1960;44:280Ð99.

50. Feist RM, Ticho BH, Shapiro MJ, Farber M. Branch retinal vein occlusion and quadratic variation in arteriovenous crossings. Am J Ophthalmol. 1992;113: 664Ð8.

51. Mansour AM, Walsh JB, Henkind P. Optic disc size in central retinal vein occlusion. Ophthalmology. 1990;97:165Ð6.

52. Dorner GT, Polska E, Garhofer G, et al. Calculation of the diameter of the central retinal artery from noninvasive measurements in humans. Curr Eye Res. 2002;25:341Ð5.

53.Baleanu D, Ritt M, Harazny J, et al. Wall-to-lumen ratio of retinal arterioles and arteriole-to-venule ratio of retinal vessels in patients with cerebrovascular damage. Invest Ophthalmol Vis Sci. 2009;50:4351Ð9.

54.Jonas JB, Nguyen XN, Naumann GOH. Parapapillary retinal vessel diameter in normal and glaucoma eyes I. Morphometric data. Invest Ophthalmol Vis Sci. 1989;30:1599Ð603.

55. Larsen M, Colmorn LB, Bonnelycke M, et al. Retinal artery and vein diameters during pregnancy in diabetic women. Invest Ophthalmol Vis Sci. 2005;46: 709Ð13.

56.Wybar KC. Anastomoses between the retinal and ciliary arterial circulations. Br J Ophthalmol. 1956;40: 65Ð81.

57.Hayreh SS. The cilio-retinal arteries. Br J Ophthalmol. 1963;47:71Ð89.

58. Hayreh SS, Jonas JB. Optic disc and retinal nerve Þber layer damage after transient central retinal artery occlusion: an experimental study in rhesus monkeys. Am J Ophthalmol. 2000;129:786Ð95.

59. Stone J, Itin A, Alon T, et al. Development of retinal vasculature is mediated by hypoxia-induced vascular endothelial growth factor (VEGF) expression by neuroglia. J Neurosci. 1995;15:4738Ð47.

60.Henkind P. Radial peripapillary capillaries of the retina. I. Anatomy: human and comparative. Br J Ophthalmol. 1967;51:115Ð23.

61.Iwasaki M, Inomata H. Relation between superÞcial capillaries and foveal structures in the human retina. Invest Ophthalmol Vis Sci. 1986;27:1698Ð705.

62. Mansour AM, Jampol LM, Logani S, et al. Cottonwool spots in acquired immunodeÞciency syndrome compared with diabetes mellitus, systemic hypertension, and central retinal vein occlusion. Arch Ophthalmol. 1988;106:1074Ð7.

63.Gariano RF, Iruela-Arispe ML, Hendrickson AE. Vascular development in primate retina: comparison of laminar plexus formation in monkey and human. Invest Ophthalmol Vis Sci. 1994;35:3442Ð55.

64.Bloodworth JMB, Molitor DL. Crystallike bodies in dog retinal capillary endothelial cells. Invest Ophthalmol Vis Sci. 1965;4:285Ð9.

65.Dosso AA, Leuenberger PM, Rungger-Brandle E. Remodeling of retinal capillaries in the diabetic hypertensive rat. Invest Ophthalmol Vis Sci. 1999;40:2405Ð10.

66.Linsenmeier RA, Padnick-Silver L. Metabolic dependence of photoreceptors on the choroid in the normal and detached retina. Invest Ophthalmol Vis Sci. 2000;41:3117Ð23.

67.Wang Y. Pilot study of optical coherence tomography

measurement of retinal blood ßow in retinal and optic nerve diseases. Invest Ophthalmol Vis Sci. 2011;52: 840Ð5.

68. Chakravarthy U, Gardiner TA, Anderson P, et al. The effect of endothelin 1 on the retinal microvascular pericyte. Microvasc Res. 1992;43:241Ð54.

69.Dodge AB, Hechtman HB, Shepro D. Microvascular endothelial-derived autacoids regulate pericyte contractility. Cell Motil Cyoskeleton. 1991;18:180Ð8.

70.Matsugi T, Chen Q, Anderson DR. Contractile responses of cultured bovine retinal pericytes to angiotensin II. Arch Ophthalmol. 1997;115:1281Ð5.

71.Schulman J, Jampol LM, Goldberg MF. Large capillary aneurysms secondary to retinal venous obstruction. Br J Ophthalmol. 1981;65:36Ð41.

72.Roberts WG, Palade GE. Increased microvascular permeability and endothelial fenestration induced by vascular endothelial growth factor. J Cell Sci. 1995;108:2369Ð79.

73.McAllister IL, Vijayasekaran S, Chen SD, Yu DY. Effect of triamcinolone acetonide on vascular endothelial growth factor and occludin levels in branch retinal vein occlusion. Am J Ophthalmol. 2009;147:838Ð46.

74.Burns MS, Hartz MJ. The retinal pigment epithelium induces fenestration of endothelial cells in vivo. Curr Eye Res. 1992;11:863Ð73.

75.Korte GE, Reppucci V, Henkind P. RPE destruction causes choriocapillary atrophy. Invest Ophthalmol Vis Sci. 1984;25:1135Ð45.

76.Riva C, Petrig B. Blue Þeld entoptic phenomenon and blood velocity in the retinal capillaries. J Opt Soc Am. 1980;70:1234Ð8.

77.Hamilton AM, Kohner EM, Rosen D, et al. Experimental retinal branch vein occlusion in rhesus monkeys. I. Clinical appearances. Br J Ophthalmol. 1979;63:377Ð87.

78.Beaumont PE, Kang HK. Clinical characteristics of retinal venous occlusions occurring at different sites. Br J Ophthalmol. 2002;86:572Ð80.

79.Hayreh SS, Hayreh MS. Hemi-central retinal vein occlusion. Pathogenesis, clinical features, and natural history. Arch Ophthalmol. 1980;98:1600Ð9.

80.Hayreh SS. Retinal vein occlusion. Indian J Ophthalmol. 1994;42:109Ð32.

81. Pollack A, Dottan S, Oliver M. The fellow eye in retinal vein occlusive disease. Ophthalmology. 1989;96: 842Ð5.

82.Chopdar A. Hemi-central retinal vein occlusion. Pathogenesis, clinical features, natural history, and incidence of dual trunk central retinal vein. Trans Ophthalmol Soc UK. 1982;102:241Ð8.

83. Shah VA, Chalam KV. Intraocular segment of the central retinal vein. Ophthalmic Surg Lasers. 2005; 36:174Ð5.

84. Ruskell G. The retinopial vein: a vein passing directly from the retina to the pia mater at the optic nerve head. Br J Ophthalmol. 1998;82:495Ð7.

85. Barcsay G, Seres A, Nemeth J. The diameters of the human retinal branch vessels do not change in darkness. Invest Ophthalmol Vis Sci. 2003;44:3115Ð8.

86. Strahlman ER, Quinlan PM, Enger C, Elman MJ. The cup-to-disc ratio and central retinal vein occlusion. Arch Ophthalmol. 1989;107:524Ð5.

87.Williamson TH. A ÒthrottleÓ mechanism in the central retinal vein in the region of the lamina cribrosa. Br J Ophthalmol. 2007;91:1190Ð3.

88.Taylor AW, Sehu W, Williamson TH, Lee WR. Morphometric assessment of the central retinal artery and vein in the optic nerve head. Can J Ophthalmol. 1993;28:320Ð4.

89.Jonas JB. Ophthalmodynamometric assessment of the central retinal vein collapse pressure in eyes with retinal vein stasis or occlusion. Graefes Arch Clin Exp Ophthalmol. 2003;241(5):367Ð70.

90.Behrman S. Retinal vein obstruction. Br J Ophthalmol. 1962;46:336Ð42.

91. Yao Y, Ma Z, Zhao J. Luminal characteristics of the central retinal vessels in the anterior optic nerve of the young human. Retina. 2002;22:449Ð54.

92.Dobree JH. Venous obstruction and neovascularization at the disc in chronic glaucoma. Trans Ophthalmol Soc UK. 1957;77:229Ð37.

93.Papamatheakis DG, Devaux A, Cordahi G, Harasymowycz PJ. Chronic angle-closure glaucoma

secondary to a suprachoroidal effusion induced by central retinal vein occlusion. Ophthalmic Surg Lasers. 2007;38:248Ð9.

94. Seitz R. The retinal vessels. St. Louis: C.V. Mosby Company; 1964. p. 1Ð186.

95. Jefferies P, Clemett R, Day T. An anatomical study of retinal arteriovenous crossings and their role in the pathogenesis of retinal branch vein occlusion. Aust N Z J Ophthalmol. 1993;21:213Ð7.

96. Tang WM, Han DP. A study of surgical approaches to retinal vascular occlusions. Arch Ophthalmol. 2000;118:138Ð43.

97. Weinberg D, Dodwell DG, Fern SA. Anatomy of arteriovenous crossings in branch retinal vein occlusion. Am J Ophthalmol. 1990;109:298Ð302.

98. Duker JS, Brown GC. Anterior location of the crossing artery in branch retinal vein obstruction. Arch Ophthalmol. 1989;107:998Ð1000.

99. Zhao J, Sastry S, Sperduto R, et al. Arteriovenous crossing patterns in branch retinal vein occlusion. Ophthalmology. 1993;100:423Ð8.

100.Mitchell P, Smith W, Chang A. Prevalence and associations of retinal vein occlusion in Australia: the Blue Mountains Eye Study. Arch Ophthalmol. 1996;114:1243Ð7.

101.Kumar B, Yu DY, Morgan WH, et al. The distribution of angioarchitectural changes within the vicinity of the arteriovenous crossing in branch retinal vein occlusion. Ophthalmology. 1998;105:424Ð7.

102.Cugati S, Wang JJ, Rochtchina E, Mitchell P. Tenyear incidence of retinal vein occlusion in an older population: the Blue Mountains Eye Study. Arch Ophthalmol. 2006;124:726Ð32.

103.Staurenghi G, Lonati C, Aschero M, Orzalesi N. Arteriovenous crossing as a risk factor in branch retinal vein occlusion. Am J Ophthalmol. 1994;117:211Ð3.

104.Klein R, Klein BEK, Moss SE, Meuer SM. The epidemiology of retinal vein occlusion: the Beaver Dam Eye Study. Trans Am Ophthalmol Soc. 2000;98: 133Ð43.

105.Christoffersen NLB, Larson M. Pathophysiology and hemodynamics of BRVO. Ophthalmology. 1999;106:2054Ð62.

106.Khan J, Chong V. Two retinal vein occlusions in a patient with venous tortuosity at the optic disc. Graefes Arch Clin Exp Ophthalmol. 2007;245:313Ð4.

107.Ohara K, Okubo A, Sasaki H, Kamata K. Branch retinal vein occlusion in a child with ocular sarcoidosis. Am J Ophthalmol. 1995;119:801Ð2.

108.Lahey JM, Tunc M, Kearney J, et al. Laboratory evaluation of hypercoagulable states in patients with

central retinal vein occlusion who are less than 56 years of age. Ophthalmology. 2002;109:126Ð31.

109.Vine AK, Samama MM. The role of abnormalities in the anticoagulant and Þbrinolytic systems in retinal vascular occlusions. Surv Ophthalmol. 1993;37: 283Ð92.

110.Incorvaia C, Parmeggiani F, Costagliola C, et al. The heterozygous 20210 G/A genotype prevalence in patients affected by central and branch retinal vein occlusion: a pilot study. Graefes Arch Clin Exp Ophthalmol. 2001;239:251Ð6.

111.Hayreh SS, Zimmerman MB, Podhajsky P. Hematologic abnormalities associated with various types of retinal vein occlusion. Graefes Arch Clin Exp Ophthalmol. 2002;240:180Ð96.

112.The SCORE Study Research Group. A randomized trial comparing the efÞcacy and safety of intravitreal triamcinolone with standard care to treat vision loss associated with macular edema secondary to branch retinal vein occlusion: the standard care vs corticos-

teroid for retinal vein occlusion (SCORE) Study Report 6. Arch Ophthalmol. 2009;127:1115Ð28.

113.Rabinowicz IM, Litman S, Michaelson IC. Branch venous thrombosis a pathological report. Trans Ophthalmol Soc UK. 1969;88:191Ð210.

114.Bowers D, Finkelstein D, Wolff S, Green W. Branch retinal vein occlusion: a clinicopathologic case report. Retina. 1987;7:252Ð9.

115.Stewart RMK, Clearkin LG. Insulin resistance and autoregulatory dysfunction in glaucoma and retinal vein occlusion. Am J Ophthalmol. 2008;145:394Ð6.

116.Kaderli AA, Kaderli B, Gullulu S, Avci R. Impaired aortic stiffness and pulse wave velocity in patients with branch retinal vein occlusion. Graefes Arch Clin Exp Ophthalmol. 2010;248:369Ð74.

117.Gopinath B, Wang JJ, Flood VM, et al. The associations between blood levels of homocysteine, folate, vitamin B12, and retinal vascular caliber. Am J Ophthalmol. 2009;148:902Ð9.

118.Hockley DJ, Tripathi RC, Ashton N. Experimental retinal branch vein occlusion in rhesus monkeys. III. Histopathological and electron microscopical studies. Br J Ophthalmol. 1979;63:393Ð411.

119.Wallow I. Cystoid macular degeneration. Ophthalmology. 1988;95:1373Ð8.

120.The Eye Disease Case-Control Study Group. Risk factors for branch retinal vein occlusion. Am J Ophthalmol. 1993;116:286Ð96.

121.Frangieh GT, Green WR, Barraquer-Somers E, Finkelstein D. Histopathologic study of nine branch retinal vein occlusions. Arch Ophthalmol. 1982;100:1132Ð40.

122.DePaola N, Gimbrone MA, Davies PF, Dewey CF. Vascular endothelium responds to ßuid shear stress gradients. Arterioscler Thromb. 1992;12:1254Ð7.

123.Chan CC, Green WR, Rice TA. Experimental occlusion of the retinal vein. Graefes Arch Clin Exp Ophthalmol. 1986;224:507Ð12.

124.Green WR, Chan CC, Hutchins GM, Terry JM. Central retinal vein occlusion: a prospective histopathologic study of 29 eyes in 28 cases. Retina. 1981;1:27Ð55.

125.Hayreh SS, Podhajsky PA, Zimmerman MB. Natural history of visual outcome in central retinal vein occlusion. Ophthalmology. 2011;118:119Ð33.

126.Hayreh SS, van Heuyen WAJ, Hayreh MS. ExperimentalretinalvascularocclusionI.Pathogenesis of central retinal vein occlusion. Arch Ophthalmol. 1978;96:311Ð23.

127.Minturn J, Brown GC. Progression of nonischemic central retinal vein obstruction to the ischemic variant. Ophthalmology. 1986;93:1158Ð62.

128.Koizumi H, Ferrara DC, Brue C, Spaide RF. Central retinal vein occlusion case-control study. Am J Ophthalmol. 2007;144:858Ð63.

129.Opremcak EM, Bruce RA, Lomeo MD, et al. Radial optic neurotomy for central retinal vein occlusion: a retrospective pilot study of 11 consecutive cases. Retina. 2001;21:408Ð15.