Home About us Editorial board Ahead of print Current issue Search Archives Submit article Instructions Subscribe Contacts Login 
  • Users Online: 15992
  • Home
  • Print this page
  • Email this page

   Table of Contents      
ARTICLES
Year : 1977  |  Volume : 25  |  Issue : 3  |  Page : 17-19

Course of the nerve fibres in the temporal half of the retina


Postgraduate Institute of Medical Education and Research, Chandigarh, India

Correspondence Address:
D N Gangwar
Postgraduate Institute of Medical Education and Research, Chandigarh
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


PMID: 614267

Rights and PermissionsRights and Permissions

How to cite this article:
Gangwar D N, Jain I S, Dhir S P. Course of the nerve fibres in the temporal half of the retina. Indian J Ophthalmol 1977;25:17-9

How to cite this URL:
Gangwar D N, Jain I S, Dhir S P. Course of the nerve fibres in the temporal half of the retina. Indian J Ophthalmol [serial online] 1977 [cited 2020 Aug 4];25:17-9. Available from: http://www.ijo.in/text.asp?1977/25/3/17/31263

Examination of opaque nerve fibres provides a unique opportunity to study the topography of nerve fibres in the retina.

The nerve fibre layer consists of the axons of the ganglion cells which pass through the lamina cribrosa to form the optic nerve. The nerve fibres are arranged in bundles which run parallel to the surface of the retina. They are not normally visible by ophthalmoscope, how­ever, when the myelin sheath is continued beyond the optic disc, they can be seen as opaque nerve fibres. The direction of fraying of these opaque nerve fibres shows their course and reveals the pattern in their distribution.

The basic pattern of arrangement of the nerve fibres in the retina has been well studied by field defect patterns, histological examina­tion as well as by study of opaque nerve fibres. This basic pattern is demonstrated in [Figure - 1]. by Harrington[2] Much emphasis has been devoted to the study of arrangement of fibres in the macular area, only little information is available of their arrangement in the peripheral part of retina. We present two cases of opaque nerve fibres which are of special interest as they show opa­que nerve fibres in the central and peripheral regions of the retina.

Case No. 1:

On routine examination of the fundus of young adult male opaque nerve fibres were found in the right eye. The distribution of the opaque nerve fibres as seen in funds is shown [Figure - 2]. The arrangement of fibres at the horizontal raphe is of special interest [Figure - 3]. It is seen that the temporal axons take a curved course. This curve become increasingly greater in the macular region. In the region of the horizontal raphe the courses of axons are of three types. Immediately, adjacent to fovea the fibres are vertical. Further temporal they become oblique. This obliquity is further accentuated into a curve. Thus the fibres arising from the temporal part of raphe describe a double S shaped curve in their course towards the optic disc viz. first curve with a concavity towards the periphery (C-I) and second curve with concavity towards the macula (C-2). This is shown diagramatically in [Figure - 4].

Case No. 2:

This adult male patient seen with unrelated com­plaints showed opaque nerve fibres in the infero­temporal quadrant to the right eye [Figure - 5] in the region of equator and beyond. The direction of fraying of these opaque nerve fibres in this lower part described an unusal curve with concavity towards six O'clock position [Figure - 6]. The conjoint effect of the two cases is shown diagramatically in [Figure - 4].


  Comments Top


All the fibres in the nerve fibre layer con­verge towards the optic disc. Those from the nasal side reach it without interruption. Those from temporal side do not pass through the macula but have to go around it. The fibres above the horizontal meridian pass above the macula and those below it pass under it. Thus, we find to the lateral side of the macula a sort of raphe from which the nerve fibres arise in a pennate manner.[1] The course of the temporal axons is curved, and becomes increasingly grea­ter in the macular region. In the region of the raphe the courses of the axons are of three types-vertical, oblique and triangular. The vertical axons are more numerous[3]. Posner and Schlossman[4] have suggested existence of nasal arcuate fibres in temporal juxta papillary region. Although this arrangement explains some of the field defects corresponding to this area, the existence of these fibres has been ques­tioned on histological basis[5].

Case No. 1 demonstrates that the fibres arising from the temporal part of the raphe' describe a double S shaped curve. First the concavity is towards the periphery (C-1) and the second concavity is towards the macula (C-2) [Figure - 4]. Further, as demostrated by case No. 2 the first curve present in the central fibres is continued to the peripheral fibres in the temporal half of the retina. It appears that fibres arising even at the equator and beyond do not have a straight course to the optic disc but rather have an initial curved course with concavity towards the periphery and later a reverse curve with concavity towards the macula. It appears that all the temporal fibres arising from the raphe and beyond describe an S shaped course and not a single curve with concavity towards the macula.


  Summary Top


Two cases of opaque nerve fibres of the retina showing the direction of fraying in the central and peripheral part of the retina have been presented. The temporal fibres arising from the raphe and beyond described an unu­sual S shaped course and not a single curve with concavity towards the macula has been reported in the literature.

 
  References Top

1.
Greef, 1900 Quoted from Wolff, E. The Anatomy of the Eye and orbit. Fourth Ed. 107 H.K. Lewis and Co. Ltd. London.  Back to cited text no. 1
    
2.
Harrington, D.O., 1976. A text Book and Atlas of Clinical Perimetery, The C.V. Mosby Com­pany, Saint Louis 68.  Back to cited text no. 2
    
3.
Hogan, M.J., Alvarado, J.A., Weddell, J.E. 1971. Histology of the human eye, 536. W.B. Saunders Co., London.  Back to cited text no. 3
    
4.
Posner, A.. and Schlossman, A., 1948. Arch. Ophth. 39,623.  Back to cited text no. 4
    
5.
Vrabec: 1960., Amar. J. Ophth. 62. 926  Back to cited text no. 5
    


    Figures

  [Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6]



 

Top
 
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
Comments
Summary
References
Article Figures

 Article Access Statistics
    Viewed3373    
    Printed48    
    Emailed0    
    PDF Downloaded0    
    Comments [Add]    

Recommend this journal