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| CASE REPORT |
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| Year : 1998 | Volume
: 46
| Issue : 2 | Page : 110-111 |
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Bilateral accessory Iris membrane
SM Bhatti, HK Kapoor
Christian Medical College and Hospital, Ludhiana, India
Correspondence Address:
S M Bhatti
Christian Medical College and Hospital, Ludhiana
India
 Source of Support: None, Conflict of Interest: None  | Check |
PMID: 9847487 
How to cite this article:
Bhatti S M, Kapoor H K. Bilateral accessory Iris membrane. Indian J Ophthalmol 1998;46:110-1 |
Accessory iris membrane is a rare congenital anomaly resulting from hyperlasia of the superficial mesodermal layer of the iris.[1] It presents as an additional layer of iris tissue giving the impression that the iris is duplicated. We present a unique case of bilateral accessory iris membrane associated with microcornea.
| Case Report | |  |
A 24-year-old male presented with history of low vision in the right eye since childhood. There was no family history of any eye problem and his parents were not consanguineous. On examination, unaided visual acuity in the right eye was 1/60 with no improvement on refraction. Visual acuity in the left eye was 6/18, which improved to 6/6 after refraction (+1.0 D, +2.75 D x 130°). Right eye had esotropia (16 prism dioptres) and was amblyopic. The horizontal corneal diameter in both eyes was 9.5 mm. In the right eye, from the anterior aspect of the iris bulged forward a normal coloured additional iris layer with multiple full-thickness irregular defects and a pseudopupil in the centre [Figure:1]. This accessory layer of iris tissue commenced from a prominent collarette at approximately 2 mm from the pupillary margin. Superiorly, the pupillary end of the accessory layer was adherent to the lens which had localised cataractous changes at the site of attachment. The fundus was not clearly visible in this eye; the disc however appeared to be normal. The left eye also had a similar well developed accessory iris layer commencing at the collarette, with a spurious pupillary aperture and multiple defects [Figure:2]. In this eye one strand of the accessory layer adherent to the lens at 5 o'clock position and there were a few pigment deposits on the anterior lens surface. The lens was clear, however, and the fundus was normal. In both eyes the normal pupil was seen through the defects and was reacting to light unlike the spurious pupil. The intraocular pressure was 14 mm Hg in both eyes, and the angle of anterior chamber was open (30°, regular, scleral spur: Spaeth grading system) in both eyes. On general physical examination the patient had no other systemic disorders.
| Discussion | | |
In the embryonic life, the superficial mesodermal layer of the iris which terminates at the lesser circle normally undergoes atrophy and persists only as a thin tissue interspersed with crypts.[1],[2] Rarely this stromal layer of iris may be hypertrophied resulting in an anterior accessory layer of iris tissue giving the appearance that the iris is duplicated. The hyperplasia may present in various forms, it may affect a segment of iris or may occur around the entire circumference of the pupil. In extreme cases it may extend across the pupil with multiple full-thickness defects and a virtual second pupillary aperture which however has no muscular activity. This condition is usually sporadic but occasionally it may have an autosomal dominant mode of inheritance. We examined all members of our patient's family covering three generations, but none of the family members had similar finding or any other ocular anomaly.
Accessory iris membrane is a rare congenital disorder. Few reports of this anomaly were published in the past,[1] but to the best of our knowledge this condition has not been reported in recent literature. Its association with persistent pupillary membrane, coloboma and anterior polar cataract has been previously reported.[1],[3]This case report is of a unique case of bilateral accessory iris membrane associated with microcornea in both eyes, and cataract in one eye. In 1957, Levy reported a case of bilateral accessory iris membrane with persistent pupillary membrane but no other associated ocular anomalies.[3] There are conflicting reports in literature about the overlapping nature of accessory iris membrane and extreme forms of persistent pupillary membrane.[4] Although these two conditions have similar origin, the clinical appearance of the two entities is quite different. Persistent pupillary membrane even in its extreme forms presents as a translucent or opaque membranous structure and extends across the pupil. Whereas in accessory membrane, also called iris duplication, the accessory layer closely resembles the normal iris tissue in colour and thickness. Also, the anterior accessory iris layer may be differentiated to form a virtual second pupillary aperture unlike the former condition. Microscopically, it has been demonstrated in the past that in case of accessory iris membrane the accessory tissue shows an extensive anomalous hyperplasia even when compared with pupillary membrane at the stage in fetal life when it has reached its maximum development.[1] Hence this condition is separate entity and should be classified a hyperplasia of the stromal layer of iris and rightly called accessory iris membrane.
| References | | |
| 1. | Duke-Elder S. System of Ophthalmolgy. London: Henry Kimpton; 1964. Vol 3, part 2. p 587-89.  |
| 2. | Sorsby A. Modern Ophthalmolgy. 2nd ed. London: Butterworths; 1972. Vol 3. p 267. |
| 3. | Levy WJ. Congenital iris lesion. Br j Ophthalmology 1957;41:120-23 [ PUBMED] |
| 4. | Cassady JR, Light A. Familial persistent pupillary membranes. Arch Ophthalmol 1957;58:438-48. [ PUBMED] |
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