|Year : 1969 | Volume
| Issue : 3 | Page : 115-116
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
|Date of Web Publication||10-Jan-2008|
Department of Ophthalmology, Maulana Azad Medical College and Associated Irwin and G. B. Pant Hospitals, New Delhi
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Malik S, Singh G, Gupta A K. Posterior embryotoxon. Indian J Ophthalmol 1969;17:115-6
Prominence of the anterior border ring of Schwalbe was termed as posterior embryotoxon by Axenfeld  , the peripheral refractile posterior corneal ring by Graves and posterior marginal dysplasia of the cornea by Streiff  .
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.
| Discussion|| |
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  ----15 per cent and Streiff,  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,  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  ) 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  ; Biozzi and Lugli  Ascher  and others). However, occurrence in this case was sporadic without any other member of the family being affected.
| Summary|| |
A rare case of posterior embryotoxon with sporadic occurrence has been reported.
| References|| |
Ascher, K, W. (1941) Amer. J. Opth. 24, 615.
Axenfeld, T. (1920) Ber. (Itsch. Ophaim. Ges. 42, 301.
Burian, 11. M. Barley, A. E. and Allen, L. (1955) Trans. Anger. Ophthal. Soc. 52, 389-428.
Biozzi, G. & Lu,gli, L., (1935). Grades Arch. Ophth, 124, 287.
Duke Elder, W. S System of Ophthal. Vol. III Rent. Congenital del. PP, 519521: 1964.
Francois, J. 1lcrcdity in ophthalmelology. (1961) St. Louis. The C. V. Mosby Company 1961, pp. 298-300.
Streiff, J. (1949) Ophthalmologica, 105, 228 (1943); 118, 81.5.
Waardenberg, P. J. (1932) The human Eye (in German) U. Serne, Erbanlagen Haag.
[Figure - 1]