|Year : 1982 | Volume
| Issue : 2 | Page : 95-97
Peripheral scotomas in glaucoma
BM Khamar, RB Khandekar, BK Ghodadra, SK Narang
M & J Institute of Ophthalmology, Ahmedadad, India
B M Khamar
M & J Institute of Ophthalmology, Ahmedabad
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Khamar B M, Khandekar R B, Ghodadra B K, Narang S K. Peripheral scotomas in glaucoma. Indian J Ophthalmol 1982;30:95-7
|How to cite this URL:|
Khamar B M, Khandekar R B, Ghodadra B K, Narang S K. Peripheral scotomas in glaucoma. Indian J Ophthalmol [serial online] 1982 [cited 2020 Nov 26];30:95-7. Available from: https://www.ijo.in/text.asp?1982/30/2/95/28086
Chronic simple glaucoma is characterised by increase intraoccular pressure, disc changes .and field changes. Of these, field changes represent the functional loss caused by the disease process. Field changes occur in central as well as peripheral fields. Field changes in the central field are paracentral scotoma, enlargement of blind spot, arcuate scotoma and ring scotoma. In the peripheral fields there is gradual constriction of field. Nasal step and sector shaped defect can take place in central as well as peripheral field. So far scotomas in the peripheral fields are not described. In this paper we present the scotomas found in peripheral fields in patients of chronic simple glaucoma.
| Materials and methods|| |
Data presented here is from 200 fields (Kinetic perimetry) plotted with Goldmann's perimeter of persons suffering from chronic simple glaucoma.
| Observations|| |
21 peripheral scotomas were seen in 17 (8.5 %) fields.
These scotomas were associated with classical field changes as described for glaucoma [Table - 1].
These scotomas vary widely in their radial site and radial extent but were mainly situated beyond 20° (outside Bjerrum's area) [Table - 2].
The scotomas situated central to 25° circle has larger radial extent. There was no correlation between radial and meridional extent which varies from 10° to 360° [Table - 3]. All scotomas demonstrated concentric configuration and had meridional extent more than radial extent except in one small circular scotoma measuring 10° X 10°. When peripheral scotomas were large and extending the central field, they were seen to be coming from blind spot.
In few cases static perimetry was also performed and it confirmed the findings of kinetic perimetry. Refractive error was not found to be associated in any way.
| Discussion|| |
Scotomas in the peripheral fields are not described so far probably because much of attention regarding scotometry has been given to central fields only. Peripheral fields are plotted to outline only the peripheral extent and keep a check on its progress. This might also be because prior to development of advanced hemispherical projection perimeter like Goldmann's, it was not possible to plot accurately peripheral and central fields with a single instrument.
In this study it was done with Goldmann's perimeter and attempt was made to find out scotomas from central as well as peripheral fields.
Such, scotomas can be because of high refractive error and prismatic effect of glasses. But this was not seen in cases with scotomas in peripheral fields. To have a 100% proof fields were plotted without glasses or change in glasses and with static perimetry in few selected cases but results were not changed in these cases and so refractive change cannot be accounted for these changes.
In all teases here was no visible fundus pathology as seen with direct ophthalmoscope and so pathology other than glaucoma cannot be the cause.
All cases had classical field defects of chronic simple glaucoma and so glaucoma should be considered responsible for the field defects found.
Peripheral scotomas were found in all types of field defects-early like paracentral scotoma [Figure - 1] intermediate like areuate scotoma [Figure - 2] and advanced like central field with temporal island [Figure - 3] They also varied in their presentation from isolated small scotomas to concentric ring scotomas, mimicking field defects normally occurring in central fields. This again reflects same pathology for causing the identical defects.
This can also be appreciated from the fact that all throughout retina nerve fibers are arranged in concentric pattern arising from blind spots. In peripheral scotomas also a association with blind spot can be demonstrated as in case in central fields [Figure - 2]
| Summary|| |
Scotomas in peripheral fields are described. They are found in 8.5°,0 of fields and are associated with classical field defects of glaucoma.
[Figure - 1], [Figure - 2], [Figure - 3]
[Table - 1], [Table - 2], [Table - 3]