Experimental ocular siderosis after extrabulbar administration of iron.

The authors studied the penetration of iron administered extrabulbarly into the ocular tissues of rabbits. It was found that iron passes from the orbit into the eyeball and accumulates in considerable quantities in the sclera, choroid, retina, ciliary body, and even in the vitreous and corneal epithelium. However, light microscopy failed to show any damage to the ocular tissues. The mechanism by which iron penetrates into the eyeball is discussed, and comparison is made between changes in the tissues, which characterise siderosis produced by an intrabulbar iron foreign body, and those in which an extrabulbar foreign body is involved.     

铁锈症眼玻璃体视网膜手术疗效分析

目的观察铁锈症眼玻璃体视网膜手术治疗的疗效。方法回顾分析玻璃体视网膜手术治疗眼后段磁性异物诱发眼铁锈症22例22只眼的临床资料。男性21例,女性1例;年龄6～54岁,平均年龄40岁。异物存留于眼内1个月～20年。手术前最佳矫正视力（BCVA）＜0.01者15只眼,0.01～0.15者5只眼,0.1～0.2者2只眼。玻璃体腔异物18只眼,眼球壁异物4只眼。并发白内障18只眼。合并视网膜脱离3只眼。12只眼联合环扎、硅油填充,7只眼联合环扎、C3F8填充。18只眼联合白内障摘除术。2只眼联合小梁切除术。结果 22只眼内异物均手术一次成功摘除。手术后视力增加20只眼,占90.9%,不变2只眼,占9.1%。BCVA＜0.1者7只眼,0.1～0.4者8只眼,0.5～1.0者7只眼。手术中并发症,视网膜裂孔并发局限性视网膜脱离2只眼;扩大巩膜切口,玻璃体腔积血2只眼。手术后并发症,并发白内障4只眼;黄斑下异物取出手术后3个月,硅油取出时再次发生视网膜脱离1只眼,再次硅油填充视网膜复位;C3F8填充后7 d继发视网膜脱离1只眼,再次硅油填充,手术后视网膜复位。随访结束时22只眼视网膜均在位。结论铁锈症眼玻璃体视网膜手术治疗安全、有效,可避免铁离子进一步释放,改善患者视功能。     

Study of experimental cataract produced by sugar alcohols in the organ-cultured mammalian ocular lens

Freshly isolated rabbit lenses were cultured in isosmolar TC-199 medium or hyperosmolar medium containing 180 mM sorbitol or mannitol. These experiments were performed to investigate the probable effects of hyperosmolar media on lens clarity and the ability of lens fiber cells to synthesize membrane intrinsic protein, MP-26. The data from these experiments show that incubation in hyperosmolar medium causes depressed MP-26 synthesis, whereas the presence of sugar alcohols in the culture medium induced anterior and posterior subcapsular opacities. The cation levels of lenses incubated in iso- and hyperosmolar medium were also measured. Data from these experiments revealed that although the experimental lenses display prominent opacities, their cation levels are generally similar to those of control lenses. It is proposed that the observed lens opacities are due to the presence of sugar alcohols in the culture medium and not to hyperosmolar shock.     

Electroretinographic assessment of early changes in ocular siderosis

We examined a patient with an iron intraocular foreign body and recorded electroretinograms (ERGs) before and after the removal of the foreign body by vitrectomy. The amplitudes of the rod and cone ERGs and the oscillatory potentials (OPs) in the injured eye were reduced before the operation. In addition, the photopic on-responses (b wave) were more reduced than off-responses (d wave). One year after surgery, the amplitudes of the rod, cone and photopic on- and off-responses were markedly improved to within the low normal limit. However, the OP amplitudes remained unchanged with lower values. These findings suggest that iron retinotoxicity leads to a dysfunction of all layers but the changes may be reversible in the early period of the disease. The late period iron toxicity produces more severe damage to the inner retina than the outer retina.     

Application of Prussian blue staining in the diagnosis of ocular siderosis

AIM:To explore the value of Prussian blue staining in the diagnosis of ocular siderosis.METHODS: Between January 2012 and January 2013, the Prussian blue stain used in anterior lens capsule and vitreous liquid after centrifugation from patients with definitive diagnosis and suspicious diagnosed of ocular siderosis. At the same time, give a negative control.RESULTS: Anterior lens capsule membrane and liquid of vitreous cavity from patients with definitive diagnosis and suspicious diagnosed of ocular siderosis revealed ferric ions that stained positively with Prussian blue. In the control group, there is no positive reaction.CONCLUSION: Prussian blue staining in the diagnosis of ocular siderosis has a very significant worth, suspected cases can be definitive diagnosed.     

Transformation and cytotoxicity of iron in siderosis bulbi

Ocular tissues from two enucleated and one trabeculectomized human eyes with siderosis bulbi were studied by electron microscopy. Ferritin particles were demonstrated in various cell types of the three eyes. Other types of iron were not identifiable. The ferritin particles were scattered throughout the cytoplasm, with a few particles in the nucleus and extracellular space. More ferritin particles were seen in tissues near the iron foreign body. The cells which contained numerous ferritin particles also had siderosomes, most of which were thought to be conglomerates of the ferritin particles in the secondary lysosomes. Cells with numerous ferritin particles, particularly in the siderosomes, showed vacuolar degeneration. The present study indicated that in siderosis bulbi, iron released from the iron foreign body is deposited as ferritin scattered throughout the cytoplasm and is sometimes accumulated as siderosomes, in the affinitive cells. In siderosis bulbi, the cells become damaged by the deposition of ferritin in the cytoplasm, especially in the form of siderosomes.