British3'ournal ofOphthalmology 1992; 76: 706-710
706
ORIGINAL ARTICLES
Seasonal variations in the onset of retinal vein occlusion Sohan Singh Hayreh, M Bridget Zimmerman, Patricia Podhajsky
Abstract Seasonal variation in the development of retinal vein occlusion in 1003 consecutive patients with various types of retinal vein occlusion was studied prospectively from 1973 to 1990. No seasonal variation in the onset of any type or combination of types of retinal vein occlusion was found. This refutes previous reports of such seasonal variation, which were based on small retrospective series.
Department of Ophthalmology S S Hayreh P Podhaisky
Department of Preventive Medicine and Environmental Health (Division of
Biostatistics), College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA M B Zimmermann Correspondence to: Dr S S Hayreh, Department of Ophthalmology, University Hospitals and Clinics, Iowa City, Iowa 52242, USA. Accepted for publication 22 July 1992
types of RVO, who have been seen in the ocular vascular clinic of the University Hospitals and Clinics at Iowa City since 1973. We analysed the data of 1003 patients with various types of RVO, seen consecutively in the clinic from 1973 until the end of 1990. CLASSIFICATION OF RETINAL VEIN OCCLUSION
To obtain scientifically valid information, it is essential to classify RVO into its different types. (BrJ Ophthalmol 1992; 76: 706-710) Our long-term studies on RVO have shown that in fact there are the following six distinct groups, Seasonal variation in the incidence of each one of them with very different pathodevelopment of central retinal vein occlusion' genesis, clinical presentation, course, and and 'retinal vein occlusion'2 has been reported management: (A) Central retinal vein occlusion. Our experiduring the past 5 years. Lavin and Dhillon,' in a retrospective study of 105 central retinal vein mental and clinical studies have demonstrated occlusion (RVO) cases, found a significantly that this must be divided into the following two (p
706
ORIGINAL ARTICLES
Seasonal variations in the onset of retinal vein occlusion Sohan Singh Hayreh, M Bridget Zimmerman, Patricia Podhajsky
Abstract Seasonal variation in the development of retinal vein occlusion in 1003 consecutive patients with various types of retinal vein occlusion was studied prospectively from 1973 to 1990. No seasonal variation in the onset of any type or combination of types of retinal vein occlusion was found. This refutes previous reports of such seasonal variation, which were based on small retrospective series.
Department of Ophthalmology S S Hayreh P Podhaisky
Department of Preventive Medicine and Environmental Health (Division of
Biostatistics), College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA M B Zimmermann Correspondence to: Dr S S Hayreh, Department of Ophthalmology, University Hospitals and Clinics, Iowa City, Iowa 52242, USA. Accepted for publication 22 July 1992
types of RVO, who have been seen in the ocular vascular clinic of the University Hospitals and Clinics at Iowa City since 1973. We analysed the data of 1003 patients with various types of RVO, seen consecutively in the clinic from 1973 until the end of 1990. CLASSIFICATION OF RETINAL VEIN OCCLUSION
To obtain scientifically valid information, it is essential to classify RVO into its different types. (BrJ Ophthalmol 1992; 76: 706-710) Our long-term studies on RVO have shown that in fact there are the following six distinct groups, Seasonal variation in the incidence of each one of them with very different pathodevelopment of central retinal vein occlusion' genesis, clinical presentation, course, and and 'retinal vein occlusion'2 has been reported management: (A) Central retinal vein occlusion. Our experiduring the past 5 years. Lavin and Dhillon,' in a retrospective study of 105 central retinal vein mental and clinical studies have demonstrated occlusion (RVO) cases, found a significantly that this must be divided into the following two (p
