Indian Journal of Ophthalmology

: 1969  |  Volume : 17  |  Issue : 3  |  Page : 115--116

Posterior embryotoxon

S.R.K Malik, Gurbax Singh, AK Gupta 
 Department of Ophthalmology, Maulana Azad Medical College and Associated Irwin and G. B. Pant Hospitals, New Delhi, India

Correspondence Address:
S.R.K Malik
Department of Ophthalmology, Maulana Azad Medical College and Associated Irwin and G. B. Pant Hospitals, New Delhi

How to cite this article:
Malik S, Singh G, Gupta A K. Posterior embryotoxon.Indian J Ophthalmol 1969;17:115-116

How to cite this URL:
Malik S, Singh G, Gupta A K. Posterior embryotoxon. Indian J Ophthalmol [serial online] 1969 [cited 2023 Mar 22 ];17:115-116
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Full Text

Prominence of the anterior border ring of Schwalbe was termed as pos­terior embryotoxon by Axenfeld [2] , the peripheral refractile posterior corneal ring by Graves and posterior marginal dysplasia of the cornea by Streiff [7] .

The present case is reported due to the rarity and sporadic character of the condition

 Case Report

An 18 year male attended the Eye Out Patient Department of Irwin Hos­pital for ophthalmic check up. On examination the unaided visual acuity was 6/6 in both eyes. The cornea in the left eye showed a glassy white annular membrane 1.5 mm all around the cornea [Figure 1]. It was refractile. Slit Lamp examination revealed it situated on the posterior surface of the cornea. Gonioscopy revealed the prominence of Schwalbe's ring with insertion of the pectinate strands which were running from the anterior sur­face of the iris to this ring. The left eye was found normal. Fundus exa­mination did not reveal any abnor­mality. The ocular muscles were nor­mal.

He was investigated for glaucoma. Diurnal variation, water drinking test, mydriatic test, priscol test and tono­graphy did not reveal any change sug­gestive of the defect.


Posterior embryotoxon is a congeni­tal anomaly characterised by the; pro­minence of the Schwalbe's ring. The incidence of minor anomaly detectible only by gonioscopy has been found to be quite common in population (Burian, Barley and Allen [3] ----15 per cent and Streiff, [7] 20 to 30 per cent). This case is of interest as it presented as a naked eye detectible lesion char­acterised by a glassy white ring 2 mm broad all around the periphery of the cornea. Such advanced manifesta­tion of the condition is very rare, an observation supported by the work of Ascher, [1] who also noted it as a rarity.

Posterior embryotoxon usually occurs as an isolated anomaly in an otherwise normal eye and is frequently associated with pectinate strands run­ning from anterior surface of the iris across the angle of the anterior cham­ber to find insertion at the prominent ridge (Duke Elder [5] ) The same obser­vation has been noted in this case.

Definite cause of the condition is un­known. However, an autosomal here­ditary tendency has been noted with familial occurrence in 2 to 3 Genera­tions (Waardenberg [8] ; Biozzi and Lugli [4] Ascher [1] and others). However, occurrence in this case was sporadic without any other member of the family being affected.


A rare case of posterior embryoto­xon with sporadic occurrence has been reported.


1Ascher, K, W. (1941) Amer. J. Opth. 24, 615.
2Axenfeld, T. (1920) Ber. (Itsch. Ophaim. Ges. 42, 301.
3Burian, 11. M. Barley, A. E. and Allen, L. (1955) Trans. Anger. Ophthal. Soc. 52, 389-428.
4Biozzi, G. & Lu,gli, L., (1935). Grades Arch. Ophth, 124, 287.
5Duke Elder, W. S System of Ophthal. Vol. III Rent. Congenital del. PP, 519­521: 1964.
6Francois, J. 1lcrcdity in ophthalmelo­logy. (1961) St. Louis. The C. V. Mos­by Company 1961, pp. 298-300.
7Streiff, J. (1949) Ophthalmologica, 105, 228 (1943); 118, 81.5.
8Waardenberg, P. J. (1932) The hu­man Eye (in German) U. Serne, Er­banlagen Haag.