Akio Majima

Local hypothermia protects the retina from ischaemic injury in vitrectomy

AIMS Hypothermic irrigating solutions were used during vitrectomy in pressure induced ischaemic eyes so that their effects on retinal function and histological changes could be investigated. METHODS After anaesthetised albino rabbits underwent closed vitrectomy, their vitreous cavities were continuously irrigated for 30 minutes at a perfusion pressure of 140 mm Hg. The rabbits were divided into three groups according to their intraocular perfusion temperatures—8°C, 22°C, and 38°C. Electroretinograms were taken before and after irrigation. Glutamate levels in the vitreous were examined after irrigation. Eyes were enucleated on the seventh postoperative day and examined histologically. RESULTS On the seventh postoperative day, the recovery rate of a-wave amplitudes was significantly lower in the 38°C group than in the 8°C group, and that of b-wave amplitudes was significantly lower in the 38°C group than in either the 8°C or 22°C group. Retinal damage in the 38°C group revealed more severe histological impairment than in either the 8°C or 22°C group. Oedema of the inner retinal layer was significant in both the 22°C and 38°C groups. Glutamates reached peak values 30 minutes after the end of ischaemia in the 38°C group. However, no significant glutamate increases were detected 15 to 60 minutes after ischaemia in either the 8°C or 22°C group. CONCLUSION Local hypothermia during vitrectomy in acute ischaemic eyes appears to decrease retinal damage.

Clinical Evaluation of Posterior Embryotoxon in One Institution

To elucidate the pathogenesis of posterior embryotoxon, we estimated its incidence in our clinic and evaluated its associated ocular and systemic anomalies. Slit-lamp and gonioscopic examinations were performed on 440 randomly selected patients at Nagoya City University Hospital over a 10-month period. Posterior embryotoxon was detected in 107, 50 bilateral and 57 unilateral, cases (24.3%). Twelve (11.2%) of the 107 cases had open-angle glaucoma. Accompanying ocular anomalies included six cases of sclerocornea, two each of persistent pupillary membrane and familial exudative vitreoretinopathy, and 1 each of melanocytoma of the optic nervehead, choroidal nevus and subconjunctival dermoid cyst. Associated systemic anomalies included three cases of Alagille syndrome, two of congenital biliary atresia, and one each of congenital facial palsy with microtia, congenital adrenal hyperplasia, empty sella syndrome, Hirschsprung disease and Wilson disease. Many of these ocular and systemic anomalies were caused by the maldevelopment of neural crest cells. Patients with posterior embryotoxon should be examined for the possible presence of open-angle glucoma and for ocular and systemic anomalies related to maldevelopment of neural crest cells.

Histochemical studies on the separation of the lens vesicle

We studied histologically the changes and distribution patterns of glycosaminoglycan molecular species during the separation of the lens vesicle in the mouse. Embryos were obtained by sacrificing pregnant mice of the Jcl: ICR strain on day 10.5 and 11 of pregnancy. Serial frontal sections were stained with hematoxylin-eosin and a sensitized high iron diamine method. To identify glycosaminoglycan molecular species in tissues, enzyme digestion (double digestions with chondroitinase B and testicular hyaluronidase) and chemical modification (nitrous acid treatment) were performed in combination with the sensitized high iron diamine method. Before separation of the lens vesicle, the glycosaminoglycan molecular species, identified in the basement membrane of the presumed corneal epithelium and intercellular matrices between the presumed corneal epithelium and lens vesicle, were chondroitin sulfate A/C and B, and those in the lens capsule were chondroitin sulfate A/C. After separation of the lens vesicle, heparan sulfate emerged in the basement membrane of the presumed corneal epithelium and intercellular matrices between the presumed corneal epithelium and lens vesicle. These results are thus taken to indicate that the changes and distribution patterns of glycosaminoglycan molecular species play an important role during separation of the lens vesicle.

Histochemical studies of glycosaminoglycans in the developing eyelids of experimental microphthalmic (Cts) mice

PURPOSE The Cts mouse is a mutant strain which induces congenital cataract and small eyes in homozygotes. The process of eyelid development in Cts mice was examined histochemically. MATERIALS AND METHODS Prenatal (from day 14 of gestation) and postnatal (to day 14) animals of unaffected and homozygous mice were examined. Sensitized high iron diamine staining was done after chondroitinase B/testicular hyaluronidase double digestion, and sensitized low iron diamine staining was done after Streptomyces hyaluronidase digestion. RESULTS The main chondroitin sulfate isomer in the dermis of the eyelid changed from chondroitin sulfate A/C to chondroitin sulfate B at birth in the unaffected mice. In the homozygotes, the same change took place 4 days after birth. In the dermis of the eyelid, hyaluronic acid was first detected on day 14 of gestation and gradually increased until birth in both unaffected and homozygous mice. There was slightly more hyaluronic acid in homozygous mice until 4 days after birth. CONCLUSION The present study showed that the maturation of glycosaminoglycan molecular species in the eyelid was retarded in Cts homozygotes.

A Case Report of Deuteranopia with Ocular Albinism: A Variant of Forsius-Eriksson Syndrome

The Forsius-Eriksson syndrome is known as an X-linked ocular anomaly with albinism of the fundus, hypoplasia of the fovea, impairment of vision, nystagmus, astigmatism, progressive myopia and protanomaly. The author encountered a 33-year-old male referred to our clinic because of a severe corneal ulcer. By ocular examinations including a color vision test with the Nagel anomaloscope, almost the same symptoms as deuteranopia instead of protanomaly were detected. His brother had similar symptoms and his mother did not have the mosaic pigment patterns in the fundus. Therefore, this case was diagnosed as a variant of the Forsius-Eriksson syndrome.