Atavistic ocular ossicle.

Abstract

Metaplastic ossification frequently follows ocular scarring. Anterior scleral ossicles are normal in most common fish, e.g. dogfish, and in reptiles, and are said to have accommodative and protective functions. Birds (2I9 out of 532 species: Tiemeier, I950) have an os opticus of highly cancellous texture lying in the posterior sclera and surrounding the optic nerve head in one or several places. Duke-Elder (1958) wrote that "no satisfactory theory for its presence has been put forward". He also mentioned the occurrence of "fatty tissue, cartilage, and even bone" in coloboma of the vitreous in microphthalmic eyes I964). This description may refer to cases now being recognized as examples of the I3-I5 trisomy syndrome. Saraux and Dhermy (I968) found a nodule of well-developed bone in the line of a uveal coloboma but located episclerally near the optic nerve. This was present in a case of D-trisomy with translocation.This paper reports a case of congenital isolated posterior intrascleral ossification, which appears to be a unique finding. Clinical historyA married woman aged 23 years was delivered at full term of her first baby on May 25, I969. She had had "tablets" for hyperemesis gravidarum in the first trimester and apart from an E. coli pyelitis, the antenatal history was uneventful. She was blood group 0 RH+. The Wassermann reaction and Venereal Disease Reference Laboratory tests were negative. There was no family history of ocular disorder. The baby girl, delivered by vacuum extraction and weighing 3 3 kg., was admitted to the Special Care Unit where she was found to have a left facial palsy and bilateral colobomata. She died 48 hours later after repeated convulsions. Skull and lateral spinal x rays, urinary chromatography, and karyotyping gave normal results. Laboratory tests showed evidence of urinary infection and the serum had low calcium, raised phosphorus, and normal electrolyte levels. Pathology AUTOPSY FINDINGSThe baby weighed 3 kg. The cranium and face appeared to be normally formed except for atypical dysplasia of the left auricle, which had a large flat helix with a single layer pointing upwards and an absent lobe. The right ear was large but had a tiny lobe. The eyes appeared to lie within normal orbital fossae. No congenital defects were found in the other systems. The cause of death was bilateral bronchopneumonia. Macroscopical examinationThe left eye measures 20 X I9 x I8 mm. with an indefinite cornea of approximately Io mm. diameter and an inferior nasal iris coloboma. The opened specimen shows a

Scleral calcification and photoreceptor cell death during aging and exposure to chronic stress

“…2Note significant (P4.01) increase in involved control eyes and rats after 4 months aging as compared with earlier periods and with experimental groups with extraocular muscle insertions in the aged human (Manschot, 1978), as well as with pseudohypoparathyroidism (Wong et al, 1979). Mullaney et al (1971) described a n "atavistic ocular ossicle" in a full-term infant as containing osteoblasts, osteoclasts, and Haversian systems and as occurring about 3 mm from the optic disc. In summary, the results of this study demonstrate a scleral site of chondro-and osteogenesis near the optic disc and nerve in the superior hemisphere of the albino rat eye.…”

“…The incidence in mammals, however, is apparently low and usually related to developmental abnormalities, genetic mutations, or disease processes (Mullaney et al, 1971;Patrinely et al, 1982). The formation of scleral plaques and scleromalacia have been described as associated "Scleral cartilage/bone formation occurred as a function of age but was unrelated to chronic stress exposure during the 6-month test period.…”

Scleral Ossification in Phthisical Eyes

“…The lens is not ossified until the capsule ruptures, and bone can be observed in areas of massive intraocular gliosis, but not in the retina itself (Monselise et al, 1985). Conversely, scleral ossification is exceedingly rare and appears to be associated with chromosomal abnormalities, such as trisomy 13-15, with the sebaceous nevus of Jadassohn (Traboulsi et al, 1999) or colobomatous eyes (Mullaney et al, 1971). Congenital episcleral osteomas are very unusual lesions, which affect the upper temporal quadrant of the globe and may be regarded as an atavistic phenomenon because bone and cartilage normally occur in the sclera of birds and reptiles (Mullaney et al, 1971).…”

“…Conversely, scleral ossification is exceedingly rare and appears to be associated with chromosomal abnormalities, such as trisomy 13-15, with the sebaceous nevus of Jadassohn (Traboulsi et al, 1999) or colobomatous eyes (Mullaney et al, 1971). Congenital episcleral osteomas are very unusual lesions, which affect the upper temporal quadrant of the globe and may be regarded as an atavistic phenomenon because bone and cartilage normally occur in the sclera of birds and reptiles (Mullaney et al, 1971). In our cases, congenital episcleral osteomas cannot be excluded with certainty; however, given the clinical history and the localization in the inferior quadrants, we consider this a secondary involvement.…”

Complex sporadic colobomata.

“…The lacrimal gland does not appear embryologically until the 25-mm stage, and the fetal cleft closes at the 15-mm stage, so possible explanations for this abnormality may be (a) a defect in the sclera into which aberrant tissue grows; this requires evidence of a colobomatous defect as in the case described by Christensen and Anderson; (b) epithelial islands developing in the aberrant tissue are carried into the mesoderm with the lens plate; or (c) the aberrant tissue develops in situ from lacrimal anlage cells sited in the primitive mesoderm. Mullaney et al (1971) reported a healthy baby (weight 3-3 kg) who died 48 hours after birth from bronchopneumonia with bilateral typical uveal colobomata extending to the optic disc. A focus of cartilage proceeding to ossification and encased by scleral mesoderm at all levels, approximately 3 mm from the left optic disc, lay immediately beneath the uveal coloboma and along the line of the embryonic fissure.…”