Yoshibumi Sekiya

Visual Function Following Congenital Cataract Surgery

To evaluate the results of congenital cataract extraction and postoperative visual function, we retrospectively reviewed the records of 95 patients who underwent pars plana (plicata) lensectomy or aspiration surgery. Forty-nine percent of the patients with bilateral aphakia and 25% with bilateral pseudophakia had a Landolt visual acuity of 0.5 or above at the final visit. The figures were 31% and 66% for patients with unilateral aphakia and pseudophakia, respectively. Eight patients (16.3%) with bilateral and 2 patients (5.8%) with unilateral cataract for whom contact lenses were prescribed after surgery attained fine stereopsis. Five of 8 patients (62.5%) with unilateral cataract who had intraocular lens implantation ended up with gross or fine stereopsis. We stress that very early surgery and optical correction in the sensitive period of binocular visual development should be instituted, especially in the presence of dense opacities. A good postoperative visual outcome can be achieved in patients undergoing late surgery if the opacities are light or partial in nature. We also reemphasize the importance of aggressive and diligent visual rehabilitation and occlusion therapy against amblyopia.

Differential expression of nitric oxide synthase isoforms in form-deprived chick eyes

PURPOSE To clarify whether nitric oxide synthase (NOS) is involved in development of myopia, we examined the influence of form deprivation on the expressions of NOS isoform mRNA. METHODS NOS isoform cDNAs were amplified from total RNA extracted from control and 7-day-form-deprived chick retina-RPE (retinal pigment epithelium)-choroid, using competitive RT-PCR (reverse-transcription polymerase chain reaction). Each NOS isoform protein was also analyzed by Western blotting and immunohistochemistry. RESULT Expression of inducible NOS (iNOS) mRNA was highest in the control chick retina-RPE-choroid, followed by the expression of brain NOS (bNOS) mRNA. Expression of endothelial NOS (eNOS) mRNA was faint. The iNOS protein level, however, was only slightly higher than the levels of the bNOS and eNOS proteins and was found mainly in the outer part of the photoreceptor layer and inner and outer parts of RPE and choroid. bNOS alone was found in the outer nuclear layer. Although form deprivation reduced the iNOS and bNOS mRNA expressions, only the iNOS protein showed significant reduction. CONCLUSION All three NOS isoforms were expressed in chick retina-RPE-choroid. Predominant expression of iNOS, instead of bNOS and eNOS, suggested the existence of ocular tissue-specific regulation of the iNOS gene. In addition to differences in expression level, bNOS displayed regional differential expression. Moreover, only iNOS was reduced in response to form deprivation. It is suggested that NOS isoforms may be differentially involved in the mechanisms regulating the posterior eye tissues, including myopic eye growth.

INTRAORBITAL ARTERIOVENOUS MALFORMATION: CASE REPORT

A case of intraorbital arteriovenous malformation presenting with visual loss, exophthalmos, and chemosis of the right eye is reported. Enhanced computer tomography and magnetic resonance imaging showed extraocular muscle enlargement and vascular abnormality in the right retrobulbar space. Angiography revealed an abnormal intraorbital vascular stain with an extremely dilated right ophthalmic artery. Total removal of the intraorbital contents was performed after unsuccessful endovascular and surgical treatment of arteriovenous malformation (AVM). Histopathological examination disclosed an AVM in the retrobulbar fatty tissue with extension into the extraocular muscles and optic nerve.

Altered Expression of Genes in Experimentally Induced Myopic Chick Eyes

PURPOSE To identify a casual pathway between the alteration in visual experience, due to form deprivation and hyperopic defocus, and the increase in eye growth, we searched for candidate genes having regulatory effects on eye growth under myopic conditions. METHODS The expression of the brain-derived neurotrophic factor, neurotrophin-3, sonic hedgehog, nerve growth factor, Six-3 and the Lh-2 group of genes in the transcriptional level after experimentally induced myopia (form-deprivation by goggles and by hyperopic defocus using negative spectacle lenses) were evaluated by semiquantitative reverse transcriptional polymerase chain reaction and Northern blot analysis. RESULTS Results showed that only the sonic hedgehog gene was differentially expressed in the experimentally induced myopic retinal samples compared with controls. CONCLUSIONS The sonic hedgehog gene may have regulatory functions in the signaling of the cascade of events that leads to axial elongation and vitreous enlargement of the eye under myopic conditions.

Intraocular lens power calculation and refractive change in pediatric cases

PURPOSE To evaluate the intraocular power calculation formula for children and the change of the refraction. SUBJECT AND METHODS We reviewed the medical records of 66 pediatric cases with intraocular lens (IOL) implantation after cataract extraction and results of questionnaire of the Japanese Association of Pediatric Ophthalmology and Japanese Society of Cataract and Refractive Surgery. We employed four IOL power calculation formulae(SRK, SRK II, SRK/T, Holladay) to evaluate the accuracy of preoperative prediction of refraction. RESULTS The best preoperative prediction was obtained by the SRK formula; the predictive refraction error within +/- 1 D was shown in 65% of patients. SRK/T and Holladay formulas were less accurate in patients aged 5 years old or younger. All formulae were less accurate in patients with axial length of 22 mm or shorter. There was no significant difference in the mean change in refraction over four years among three different age group (group 1: < = 5, group 2: 6 << = 10, group 3: 11 << = 15(years old(YO)). However, several patients aged 10(YO) or younger showed severe myopic changes during this period. CONCLUSION The IOL power calculation fomulae show less accuracy on pediatric cases. It is also difficult to predict the change of refraction on pediatric cases.

Evaluation of bilateral undefined optic neuropathy based on mitochondrial genetics

To assess exogenous environmental factors affecting the phenotypic expression of Lebers hereditary optic neuropathy (LHON), the authors divided 18 cases of bilateral optic neuropathy into two groups with or without mitochondrial (mt) DNA mutations specific for LHON and compared the ocular and other clinical findings and serum concentrations of B group vitamins between the two groups. Ten cases of defined unilateral optic atrophy were also enrolled as control. Of the 18 cases of bilateral optic neuropathy, nine had a G-to-A point mutation at nucleotide position (np) 11778 and one had the mutation at np 3460 of mtDNA. The levels of various B group vitamins were reduced in four of the 10 cases with the mtDNA mutations, three of whom were tobacco and alcohol abusers, indicating not a few numbers of the occult existence of LHON patients in so-called tobacco-alcohol amblyopia patients. Flavin mononucleotide (FMN), one of the activated forms of vitamin B2 and a co-factor of NADH dehydrogenase, was reduced in ei...

Isolation of mRNA Species Enriched in the Ocular Tissues of Form-Deprived Chick Eyes Using Differential Display

We conducted studies with mRNA differential display technology using mRNA from control and form-deprived ocular tissues of chicks. That is, each mRNA was reverse-transcribed with oligo-dT primers anchored to the beginning of the poly(A) tail and amplified by polymerase chain reaction using 10-mer oligonucleotides arbitrary in sequence as second primers. When amplified products were electrophoresed on a denaturing polyacrylamide gel, approximately 10–15 bands enriched in form-deprived ocular tissues were obtained for each second primer. The products eluted from the gel were subjected to secondary amplification and used as probes in the Northern blot analysis. When Northern blot analysis confirmed that the intense bands reflected mRNA species enriched in form-deprived ocular tissues, the products were force-cloned into pGem T vector (Promega) and subjected to sequence analysis. Until now, 21 different clones were isolated, although their sequences did not always display high homology to previously reported sequences in the DNA databases. It is not yet known whether form-deprivation induces mRNA transcription or decreases mRNA turnover. However, alteration in mRNAs by form deprivation might include signals related to the progression of experimental myopia.

Plasminogen Activator: Influence on Axial Length in Chick Eye

Transforming growth factor β (TGF-β) is thought to be a regulator of the development of form-deprivation myopia (FDM) in the chick. We investigated the change in axial length when TGF-β was activated by plasminogen activator, which is a major biologic activator of TGF-β. White leghorn chicks were treated with or without lid suture of the right eye for 10 days. Daily retrobulbal injection of (1) urokinase-plasminogen activator (uPA), (2) plasminogen activator inhibitor-1 (PAI-1), a specific inhibitor of PA, or (3) saline was performed in the right eyes of lid-sutured and nonsutured chicks. The same volume of saline was injected in the left eyes of chicks for a control. At the end of each drug trial the anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), and axial length (AL) were measured with ultrasonography. No significant change was detected in ACD or LT in the control and uPA-treated eyes or between the control and PAI-1-treated eyes with or without lid suture. In the eyes of non-lid-sutured chicks, the uPA inhibited VCD and AL, whereas PAI-1 enlarged them. In lid-sutured eyes, uPA inhibited VCD and AL, but PAI-1 showed no effect. These results suggest that activation of TGF-β influences the control of axial length in form-deprived and even nondeprived eyes.