Indian Journal of Ophthalmology

ARTICLES
Year
: 1976  |  Volume : 24  |  Issue : 4  |  Page : 23--26

The central retinal artery in the albino rats (A histological study)


KK Bisaria1, Shanno Devi Sud2,  
1 K.G.'s Medical College, Lucknow, India
2 Dept. of Ophthalmology, Vivekananda Polyclinic, Lucknow, India

Correspondence Address:
K K Bisaria
Dept. of Anatomy, K.G.«SQ»s Medical College, Lucknow
India




How to cite this article:
Bisaria K K, Sud S. The central retinal artery in the albino rats (A histological study).Indian J Ophthalmol 1976;24:23-26


How to cite this URL:
Bisaria K K, Sud S. The central retinal artery in the albino rats (A histological study). Indian J Ophthalmol [serial online] 1976 [cited 2023 Jan 30 ];24:23-26
Available from: https://www.ijo.in/text.asp?1976/24/4/23/31278


Full Text

Bruns[1] and Janes and Bounds[3] have descri­bed about the blood vessels of the retina of the rats but the work done on histological grounds in the past in this animal is almost nil. Ann Donovan[2] has even commented that histological study of the optic nerves of vertebrates are few and not always in agreement. In view of much scanty description it seemed useful to work on this study.

 Material and Methods



In all 48 eyes of the adult albino rats were used in this study. The thoracic cavity was exposed under deep ether anaesthesia and the heart was punctured to allow the animal bleed to death.

The heads of the rats were then placed in a fresh solution of 10% formaldehyde for 24 hours. T he optic nerves and eyeballs were then exposed from the top of the head region. Thus dissected specimens were put in another jar of 10% fresh solution of formaldehyde after puncturing the eyeball just behind the limbus for better fixation of the optic disc and retina for another 24 hours.

The third day eyes were enucleated with optic nerves and superior rectus which was splitted as a guide for superior pole and medial rectus kept intact to know about the inner quadrants of the eyeballs in sections.

The right and left enucleated eyes were placed in differ­ent right and left levelled glass jars. Such specimens were then washed in running distilled water for an hour and were subjected in sequence to the process of dehyd­ration in graded alcohols and embeded in paraffin. The sections of half the number of total blocks were serially cut by spencer microtome at five micron transversly and other half longitudinally. The strip of paraffin sec­tions ranging from 2-7 were mounted on the serially ar­ranged labelled slides. All the sections thus mounted were stained with haematoxylin and eosin on the next day.

 Results



The ophthalmic artery in the extraocular course ran along the region of inferonasal quadrant of the nerve [Figure 1][Figure 2]. Then it pierced the sclera in the thickness of which it indented the optic nerve [Figure 3]. In the sclera it gave off the central retinal artery as its first branch in 40 eyes [Figure 4] whereas in the rest eight eyes it divided into two branches, long posterior ciliary artery and central retinal [Figure 5]. The central retinal artery then ran obliquely anterolaterally to enter the optic disc any where between the centre and the nasal part of the optic papilla. The artery was observed running obliquely in the angular region of the disc and sclera with the accom­panying vein lying deep to it. The position of the central retinal artery was found in all cases lying anterior to the vein [Figure 4][Figure 8]. It pierced the optic disc to come in the centre [Figure 6] and then divided into its number of terminal branches [Figure 7][Figure 8].

The branches of the central retinal artery which were 4 in 4 eyes, 6 in 36 eyes and 7 in 4 eyes were all seen at the optic disc in trans­verse sections.

 Discussion



Nicholls and Tansley[4] examined the sections through the optic nerve of 214 eyes and com­mented on abnormalities on optic nerve and nothing about its blood vessels.

The central retinal artery in rats come off as first branch of the ophthalmic artery as soon as the later vessel entered the sclera but it may be one of the terminal branches of the ophthalmic artery, the other being posterior ciliary artery which turned laterally in the sclera. The central retinal artery with its vein was in all cases observed to reach the optic disc by pierc­ing the thickness of the sclera rather than to pierce the intra-orbital portion of the optic nerve as happens in the higher mammals It then ran obliquely through the optic nerve fibres of the retina to the optic disc to reach its centre. The central retinal artery at the optic disc divided into 4-7 branches.

 Summary



1. The central retinal artery in the albino rats could be the first branch or one of the ter­minal branches of the ophthalmic artery in the sclera.

2. The central retinal artery in all cases was observed to lie anterior to its accompany­ing vein at the disc.

3. The central retinal artery gave 4 to 7 terminal branches at the disc.

4. This histological study of central retinal artery is a rare work as such work is not described in detail in the past literature.

 Acknowledgement



I am greately indebted to my father Mr. R.S. Bisa­ria and to late Prof. D. Narayan, M.S., F.A.M.S,, who had been a constant source of encouragement in the pre­paration of this manuscript.

References

1Bruns, L., 1882, Ztschr. f. vergleich. Angenh., 1 , 77.
2Donovan, A. 1967, J. Anat., 101, 1.
3Janes, R.G. and Bounds. G.W., 1955, .Jour, Anat., 76, 357.
4Nicholls, J.V.V., and Tansley, K., 1938, Brit..J. Ophthal, 22,165.