Abstract
Accurate determination of retinal vessel width measurement is important in the study of the haemodynamic changes that accompany various physiological and pathological states. Currently the width at the half height of the transmittance and densitometry profiles are used as a measure of retinal vessel width. A consistent phenomenon of two 'kick points' on the slopes of the transmittance and densitometry profiles near the base, has been observed. In this study, mathematical models have been formulated to describe the characteristic curves of the transmittance and the densitometry profiles. They demonstrate the kick points being coincident with the edges of the blood column. The horizontal distance across the kick points would therefore indicate the actual blood column width. To evaluate this hypothesis, blood was infused through two lengths of plastic tubing of known diameters, and photographed. In comparison with the known diameters, the half height underestimated the blood column width by 7.33% and 6.46%, while the kick point method slightly overestimated it by 1.40% and 0.34%. These techniques were applied to monochromatic fundus photographs. In comparison with the kick point method, the half height underestimated the blood column width in veins by 16.67% and in arteries by 15.86%. The characteristics of the kick points and their practicality have been discussed. The kick point method may provide the most accurate measurement of vessel width possible from these profiles.
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- Bengtsson B., Krakau C. E. Some essential optical features of the Zeiss fundus camera. Acta Ophthalmol (Copenh) 1977 Feb;55(1):123–131. doi: 10.1111/j.1755-3768.1977.tb06101.x. [DOI] [PubMed] [Google Scholar]
- Bertram B., Wolf S., Fiehöfer S., Schulte K., Arend O., Reim M. Retinal circulation times in diabetes mellitus type 1. Br J Ophthalmol. 1991 Aug;75(8):462–465. doi: 10.1136/bjo.75.8.462. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bland J. M., Altman D. G. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986 Feb 8;1(8476):307–310. [PubMed] [Google Scholar]
- Brinchmann-Hansen O., Myhre K., Sandvik L. The light reflex in retinal vessels and its relation to age and systemic blood pressure. Acta Ophthalmol (Copenh) 1987 Apr;65(2):206–212. doi: 10.1111/j.1755-3768.1987.tb07002.x. [DOI] [PubMed] [Google Scholar]
- Bulpitt C. J., Dollery C. T., Kohner E. M. The marginal plasma zone in the retinal microcirculation. Cardiovasc Res. 1970 Apr;4(2):207–212. doi: 10.1093/cvr/4.2.207. [DOI] [PubMed] [Google Scholar]
- Delori F. C., Fitch K. A., Feke G. T., Deupree D. M., Weiter J. J. Evaluation of micrometric and microdensitometric methods for measuring the width of retinal vessel images on fundus photographs. Graefes Arch Clin Exp Ophthalmol. 1988;226(4):393–399. doi: 10.1007/BF02172974. [DOI] [PubMed] [Google Scholar]
- Delori F. C., Gragoudas E. S., Francisco R., Pruett R. C. Monochromatic ophthalmoscopy and fundus photography. The normal fundus. Arch Ophthalmol. 1977 May;95(5):861–868. doi: 10.1001/archopht.1977.04450050139018. [DOI] [PubMed] [Google Scholar]
- Eaton A. M., Hatchell D. L. Measurement of retinal blood vessel width using computerized image analysis. Invest Ophthalmol Vis Sci. 1988 Aug;29(8):1258–1264. [PubMed] [Google Scholar]
- Flower R. W., McLeod D. S., Pitts S. M. The effect of blood on ocular fundus reflectance and determination of some optical properties of retinal blood vessels. Invest Ophthalmol Vis Sci. 1978 Jun;17(6):562–565. [PubMed] [Google Scholar]
- Grunwald J. E., Riva C. E., Brucker A. J., Sinclair S. H., Petrig B. L. Altered retinal vascular response to 100% oxygen breathing in diabetes mellitus. Ophthalmology. 1984 Dec;91(12):1447–1452. doi: 10.1016/s0161-6420(84)34124-0. [DOI] [PubMed] [Google Scholar]
- Heier H., Brinchmann-Hansen O. Reliable measurements from fundus photographs in the presence of focusing errors. Invest Ophthalmol Vis Sci. 1989 Apr;30(4):674–677. [PubMed] [Google Scholar]
- Lanigan L. P., Clark C. V., Allawi J., Hill D. W., Keen H. Responses of the retinal circulation to systemic autonomic stimulation in diabetes mellitus. Eye (Lond) 1989;3(Pt 1):39–47. doi: 10.1038/eye.1989.6. [DOI] [PubMed] [Google Scholar]
- Newsom R. S., Sullivan P. M., Rassam S. M., Jagoe R., Kohner E. M. Retinal vessel measurement: comparison between observer and computer driven methods. Graefes Arch Clin Exp Ophthalmol. 1992;230(3):221–225. doi: 10.1007/BF00176292. [DOI] [PubMed] [Google Scholar]


