|Year : 1983 | Volume
| Issue : 2 | Page : 55-56
VN Prasad, A Ghosh
Department of Ophthalmology, B.R.D.Medical College, Gorakhpur, India
V N Prasad
Department of Ophthalmology B. R. D. Medical College. Gorakhpur. (U P.)
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Prasad V N, Ghosh A. Colour perimetry. Indian J Ophthalmol 1983;31:55-6
From clinical point of view there is much confusion as to the nature and extent of the visual field for colour. In addition there is extreme diversity of opinion regarding its use and diagnostic value. Diversity of opinion ranges from rejection of Harrington and the doubt of Matteucci to advocation by Traquair and Walsh.
Little data on the normal isopters of red colour is available in the Indian literature. We, with the help of Aimark projection perimeter. have charted 135 normal eyes to find out the normal field for red colour.
| Materials and methods|| |
A study of normal visual field to 3/330 red in a semidarkened room was done on 135 normal eyes with the Aimark projection perimeter. As a routine the right eve was done first, in few cases only one eye was investigated due to absent or low vision in the other eye. In all the cases colour recognition was taken as the end point. Since there is subjective change of hue of colour to the observer when a red stimulus is brought towards the fixation point, the red appears yellow, then orange, then orange red and finally red, we have taken orange as the colour recognition point.
The meridians investigated for the right and left eve are given in [Table - 1].
| Observations|| |
The fields for right and left eye were recorded and the figures collected were averaged in each meridian. The average value for 3/330 red in each meridian is given in [Table - 2].
| Discussion|| |
The normal isopter to 3/330 red was investigated in 135 normal eyes taking Colour recognition as the end point. It is of inte-rest to compare our data with other workers [Table - 3] which is in conformity with finding of other workers.
The diagnostic value of colour fields is relatively small. It does, however, provide a delicate functional assessment of the transmitting neural apparatus in which there is relative diminution of sensitivity to red and green preceding that for blue. The scotopic fovea is more sensitive to red while the scotopic periphery to blue colour.
The knowledge of normal extent of red field will help in detecting those cases with diminution of sensitivity to red and thus in early diagnosis and treatment.
| Summary|| |
A series of normal visual fields for 3/330 red were analysed in 135 eyes with Aimark. Projection perimeter in a semidarkened room. which revealed the following average measurements in the major meridians i.e. temporal-46. Up-16. nasal-17, and down-16 degrees.
| References|| |
Harrington, D. O.. 1964. The visual fields : A text book and Atlas of clinical Perimetry, St. Lewis. Mosby, p 73, 81-82
Natteucci. P.. 1948. Quantitative and qualitative perimetric studies with monochromatic and white targets. (cited by Leinfelder. P..J.: Ophthalmology in the war years Chicago, Year book, 1948. V 2).
Walsh. 1960,Text book of Neuro ophthalmology. IInd ed.
Traquair. 1957, Clinical Perimetry (G. I. Scott. ed.) St. Louis. Mosly, 1957 ed. 7
Duke-Elder; W. S., 1962, Text book of Ophthalmology, Vol. VIII 'The foundations of Ophthalmology, 'Henry Kimpton, p 419.
[Figure - 1]
[Table - 1], [Table - 2], [Table - 3]