Biomedical subjects

T Sakuraba

Publications and source records attributed to T Sakuraba.

16 recordsLinked to original sources

PubMed2001

[Ocular surface changes after dacryocystorhinostomy].

PURPOSE: To observe changes in tear film lipid interference patterns on the ocular surface in patients with nasolacrimal duct (NLD) obstruction before and after dacryocystorhinostomy (DCR). METHODS: The tear film lipid layer on the ocular surface was observed with a specular reflection video recording system in 5 eyes of 4 patients with NLD obstruction before and after DCR. Precorneal tear lipid layer interference patterns at the central cornea, tear meniscus height (TMH), and the Shirmer I test were recorded. Observed patterns were classified into 5 grades. RESULTS: Three of four eyes with TMH values over 0.4 mm before DCR showed decreased TMH postoperatively. One eye with a TMH of 0.2 mm showed no change after DCR. Concerning the tear film lipid layer interference patterns, 4 eyes were classified as grade 1 or 2, and 1 eye was classified as grade 4 before DCR. After DCR, the 5 eyes were classified from grade 3 to grade 4. Epiphora was successfully resolved in all patients after DCR. CONCLUSION: Tear film lipid layers were classified as normal grades before DCR but most cases changed to high grades after DCR. We suggest that the eye after DCR should have a thicker lipid layer than before DCR.

Aged↗

PubMed2001

[A case of suspected drug-induced ocular pemphigoid].

BACKGROUND: Lacrimal obstruction can occur as a complication of ocular cicatricial pemphigoid. We report a patient who was diagnosed as having drug-induced ocular cicatricial pemphigoid associated with acquired lacrimal canalicular obstruction in spite of relatively mild subconjunctival scar formation. CASE: The patient was a 69-year-old woman. She had been treated for glaucoma, blepharoconjunctivitis, dacryocystitis, and lacrimal canalicular obstruction for two years with topical administration including 0.5% timolol maleate, 0.1% dipivefrine hydrocholoride, 0.1% fluorometholone, and 0.3% ofloxacin. The patient had moderate conjunctival hyperemia without shortening of the inferior conjunctival sac, corneal ulceration, neovascularization, and keratinization. Lacrimal canalicular obstruction progressed further as topical ocular medications were continued. Topical anti-glaucoma medications were stopped after dacryocystorhinostomy. Although the blepharoconjunctivitis was improved, left inferior conjunctival symblepharon, and medical canthal keratinization was progressive despite the use of topical corticosteroids. The conjunctival biopsy specimen showed the lacrimal punctum covered with proliferated conjunctival epithelium. There was a moderate stromal infiltration of small lymphocytes and plasma cells. We diagnosed this patient as having drug-induced ocular cicatricial pemphigoid caused by topical anti-glaucoma medications. CONCLUSION: Lacrimal canalicular obstructions may occur with the topical anti-glaucoma medications even when subconjunctival scarring is mild.

Aged↗

PubMed2000

Morphological changes of retinal pigment epithelial and glial cells at the site of experimental retinal holes.

PURPOSE: To investigate morphological changes of retinal pigment epithelial (RPE) cells and glial cells in the immediate and early phases of restoration at the site of experimental retinal holes. METHODS: We made 0.2-disc-diameter retinal holes with a vitreous cutter in albino rabbit eyes. To assess very early changes of RPE cells, the eyes were enucleated at 0,1,3, and 5 h postoperatively and observed by scanning electron microscopy (SEM). At 1,5, and 7 days after surgery, eyes were enucleated and prepared in thin and ultra-thin sections for observation by light and transmission electron microscopy (TEM). RESULTS: SEM showed the surface of the RPE cells lifting a few hours after surgery at the site of the retinal holes. The tissue filling the retinal hole was amorphous and homogeneous, as viewed by light microscopy. TEM revealed that this tissue consisted of glial cell processes containing many organelles. In addition, the cytoplasm of the cells was relatively dark, while the surface of the filling tissue continued smoothly to the internal limiting membrane. These findings suggested that these cell processes were parts of Müller cells. CONCLUSION: RPE cells and glial cells assembling at the site of the retinal hole may play an important role in retinal hole closure in this experimental model. In addition, RPE cells were morphologically changed in an immediate phase of restoration.

Animals↗

PubMed2000

Epiretinal membranous tissue in retinal detachment due to macular holes in highly myopic eyes

Objective: To determine the frequency of occurrence of epiretinal membranous tissue in retinal detachment due to macular hole and to evaluate the efficacy of vitreous surgery including removal of the membrane.Design: Noncomparative case series.Participants: Eighteen highly myopic eyes with retinal detachment due to macular holes. Results: Epiretinal membranous tissue was removed from 7 eyes (39%) and retinal reattachment was obtained in 14 eyes (78%) after the initial vitreous surgery. Of 4 eyes that required reoperation, 2 eyes achieved reattachment after a long term of internal tamponade. Histological examination of an epiretinal membrane from one case revealed that it was composed of glial cells, connective tissue, and fragments of inner limiting membrane. An intraoperative use of autologous serum as a tissue adhesive for macular holes had no effect on surgical success.Conclusion: The first therapeutic choice for this disease should be vitreous surgery with removal of the epiretinal membrane when practical, though the membrane cannot always be identified in every case.

Journal Article↗

PubMed1999

[Predicted versus actual postoperative refractive error after simultaneous vitrectomy and cataract surgery].

PURPOSE: We compared the spread between predicted and postoperative actual refractive errors after simultaneous vitrectomy, phacoemulsification, aspiration, and acryl lens insertion and after cataract surgery alone. METHODS: Cataract surgery and vitrectomy (combined surgery group) were performed in 185 eyes, and cataract surgery only (cataract surgery group) in 63 eyes. Vitrectomy was needed for diabetic retinopathy in 104 eyes, macular hole in 26 eyes, rhegmatogenous retinal detachment in 25 eyes, and other conditions in 30 eyes. RESULTS: The spread between predicted and actual refractive errors were +0.19 +/- 1.24 D (mean +/- standard deviation) in the combined surgery group and +0.91 +/- 1.40 D in the cataract surgery group. Gas tamponade in the combined surgery group increased the myopic change more than anything else. CONCLUSION: Actual refractive errors in the combined surgery group were found to shift to myopia more than in the cataract surgery group. Gas tamponade was considered to press the intraocular lens forward in the combined surgery group.

Adult↗

PubMed1999

[Epiretinal membranous tissue in retinal detachment due to macular holes in highly myopic eyes].

OBJECTIVE: To determine the frequency of occurrence of epiretinal membranous tissue in retinal detachment due to macular hole and to evaluate the efficacy of vitreous surgery including removal of the membrane. DESIGN: Noncomparative case series. PARTICIPANTS: Eighteen highly myopic eyes with retinal detachment due to macular holes. RESULTS: Epiretinal membranous tissue was removed from 7 eyes (39%) and retinal reattachment was obtained in 14 eyes (78%) after the initial vitreous surgery. Of 4 eyes that required reoperation, 2 eyes achieved reattachment after a long term of internal tamponade. Histological examination of an epiretinal membrane from one case revealed that it was composed of glial cells, connective tissue, and fragments of inner limiting membrane. An intraoperative use of autologous serum as a tissue adhesive for macular holes had no effect on surgical success. CONCLUSION: The first therapeutic choice for this disease should be vitreous surgery with removal of the epiretinal membrane when practical, though the membrane can not always be identified in every case.

Aged↗

PubMed1997

Aspirating specula with sponge covers.

Improved aspirating specula for the removal of irrigating fluid during ocular surgery are now commercially available. Thin sponge covers are used to prevent the conjunctiva from occluding the aspiration ports, thereby ensuring continuous effective suction.

Drainage↗

PubMed1996

[Medical treatment for experimental retinal vein occlusion--thrombolytic effect of nasaruplase].

The anti-thrombolytic effect of urokinase (UK), nasaruplase, and argatroban was studied using an experimental rabbit model of retinal vein occlusion (RVO). Experimental RVO was induced by transadventitial thrombin instillation. Five or fourteen days after thrombin application, the rabbits were injected with gelatin-fluorescein sodium and their eyeballs were enucleated for microscopic observation and flat preparation of the retina. Occlusion of retinal vessels was found to be less in number and distribution in the nasaruplase group than in the control group. On microscopic observation, the retinal arteries and veins of the nasaruplase group showed a vascular subendothelial space formation which suggested a process of thrombogenesis and thrombolysis in the space. The coefficiency of beraprost sodium, aspirin, and ozagrel hydrochloride to UK therapy was studied, but there was no significant difference between these groups and the control group with no after-treatment (the UK group). This result shows the effectiveness of nasaruplase for the thrombolytic therapy of RVO.

Animals↗

PubMed1993

[Histological study on idiopathic epimacular membrane in three cases of different age].

Histological features of idiopathic premacular membrane were studied in 3 cases of different ages. All cases were female and complained of blurred vision without any causative moment. The age was 7 year in Case 1, 29 year in Case 2 and 68 year in Case 3. The cases underwent vitreous surgery with easy removal of the membranes. On light and electron microscopical observation, the membranes composed of retinal glial cells, connective tissue and the inner limiting membrane in Case 1, fibroblastic cells and connective tissues in Case 2, and connective tissues and the inner limiting membrane lacking any cellular component in Case 3. These findings strongly suggest the possibility of existence of various pathogeneity and developmental stages and types in idiopathic epimacular membrane.

Adult↗

PubMed1991

Intercapsular cataract surgery with lens epithelial cell removal. Part IV: Capsular fibrosis induced by poly(methyl methacrylate).

Characteristic lens epithelial cell behavior in the pseudophakic eye was examined by comparing 30 eyes that had extracapsular cataract surgery by the intercapsular technique and posterior chamber intraocular lens (IOL) implantation with lens epithelial cell removal but without anterior capsule capsulectomy and nine aphakic eyes that had the same procedure but without posterior chamber lens implantation over a mean follow-up period of 30 and 23 months, respectively. Fibrous anterior capsule opacification was observed in 83% of the pseudophakic eyes in the area of contact with the IOL, while the region beyond the margin of the IOL remained transparent. Fibrous anterior capsular opacification was not noted in the aphakic eyes. This suggests that the IOL material, poly(methyl methacrylate), stimulates lens epithelial cells to undergo fibrous metaplasia and to produce collagen fibers. Various cytokines such as IL-1 and TGF-beta synthesized by lens epithelial cells may play a crucial role as mediators in the process. We recommend that this effect be considered as a parameter of biocompatibility in developing and evaluating new biomaterials.

Adult↗

PubMed1991

[A case of presumed radiation optic neuropathy].

A case of a 37-year-old woman with radiation optic neuropathy was reported. She had undergone subtotal removal of the right orbital tumor (adenoid cystic carcinoma) by frontal craniotomy, followed by radiation therapy (64Gy). She had been quite well until she noticed a gradual loss of vision in her right eye 18 months later. Her visual acuity was 0.2 in the right eye and 1.5 in the left eye with right relative afferent pupillary defect and dense central scotoma. Funduscopy revealed optic disc swelling with surrounding retinal edema and small hemorrhage in the right eye. Fluorescein angiography revealed a hypoperfusion area and obstruction of the small retinal vessels in the posterior pole, but this was not large enough to explain the dense central scotoma. Although prednisolone therapy gave temporary improvement, the visual function gradually deteriorated.

Adult↗

PubMed1989

[Experimental retinal vein obstruction induced by transadventitial administration of thrombin in the rabbit].

Retinal venous obstruction with typical flame-shaped hemorrhage was experimentally produced in the rabbit by transadventitial dropping of thrombin on target vessels by vitreous surgery techniques. The changes were studied ophthalmoscopically, light and electron microscopically. Flame-shaped retinal hemorrhage appeared within 24hr after the maneuver of thrombin dropping, following the initial appearance of small hemorrhage during the first 8 to 12hr of the experiment. Microscopic study revealed the process of subendothelial fibrin-thrombus formation in the target venules. Thrombus formation began 6hr after dropping of thrombin and vascular lumina were markedly narrowed by 24hr. No endothelial defect was found in the target venule between 6 and 12hrs after thrombin dropping, though fibrin-platelet thrombi were often found in the lumina of the venules. In the arteriole, on the other hand, intramural thrombus was seen only in the earlier stage, not later than 6hr after dropping of thrombin, in the area peripheral to the site of dropping. These findings suggested the possibility of transmural effects of thrombin as well as participation of arterioles in thrombogenesis, and supports the usefulness of this experimental model for the study of retinal venous obstruction.

Animals↗

PubMedDate not supplied

Tear lipid layer interference changes after dacryocystorhinostomy.

PURPOSE: Specular images of the tear film in the central cornea were examined in patients with nasolacrimal duct obstruction to observe changes before and after dacryocystorhinostomy (DCR). METHODS: We observed the specular images in 4 patients (5 eyes) by a noncontact observation device and recording system. Observed patterns were classified into five grades. The specular images and tear meniscus height (TMH) were recorded. RESULTS: Three of the 4 eyes with TMH values over 0.4 mm before DCR showed decreased TMH postoperatively. The 1 eye with a TMH value of 0.2 mm showed no change after DCR. Using specular images, 4 eyes were classified grade 1 or 2, and 1 eye was classified grade 4 before DCR. After DCR, the 5 eyes were classified as grade 3 or grade 4. CONCLUSION: The results indicated that the eye after DCR has a thicker lipid layer than the eye before DCR.

Aged↗

PubMedDate not supplied

Postoperative refractive error after simultaneous vitrectomy and cataract surgery.

PURPOSE: To evaluate the effect of vitrectomy on postoperative refraction after simultaneous vitrectomy and cataract surgery. METHODS: We compared the spread between predicted and actual refractions in 206 eyes after a simultaneous vitrectomy, phacoemulsification, aspiration and acrylic lens insertion (combined surgery group), and in 67 eyes after cataract surgery only (cataract surgery group) as control. A vitrectomy was performed for diabetic retinopathy in 127 eyes, macular hole in 32 eyes, rhegmatogenous retinal detachment in 16 eyes, branch retinal vein occlusion in 15 eyes, and other conditions in 26 eyes. In the combined surgery group, 79 eyes had a gas tamponade after insertion of the intraocular lens. RESULTS: The spread between predicted and actual refractions was - 0.05 +/- 1.18 diopters (average +/- SD) in the combined surgery group and +0.55 +/- 1.32 D in the cataract surgery group. The actual refractive errors in the combined surgery group were found to shift toward myopia when compared with the controls. Among the combined surgery group, 127 eyes without a gas tamponade showed a postoperative refractive error of +0.14 +/- 1.11 D, while 79 eyes with a gas tamponade demonstrated an error of -0.36 +/- 1.22 D. CONCLUSIONS: Use of a gas tamponade in the combined surgery group increased the myopic change and was thought to have pressed the intraocular lens forward.

Adult↗

PubMedDate not supplied

Visual improvement after removal of submacular exudates in patients with diabetic maculopathy.

OBJECTIVE: To improve the central visual function of eyes affected by massive hard exudates in cases of diabetic maculopathy. PATIENTS AND METHODS: Six eyes of 4 patients with diabetic maculopathy were treated by pars plana vitrectomy for massive retinal exudates persisting for more than 3 months. The massive hard exudates were removed from the subretinal space with subretinal forceps. We evaluated the visual acuity of these eyes 6 months after surgery. RESULTS: Following the removal of the hard exudates, visual acuity improved in all eyes. Massive hard exudates were mainly located in the subretinal space and were removable using subretinal forceps. No serious postoperative complications occurred. The removed tissues consisted of macrophages laden with many cholestrin crystals and lipid droplets, as well as fibrous tissues. CONCLUSION: We concluded that central visual function can be improved by removing subretinal exudates surgically.

Aged↗

PubMedDate not supplied

Postoperative complications after simultaneous vitrectomy and cataract surgery.

OBJECTIVE: We reviewed postoperative complications after simultaneous vitrectomy, phacoemulsification, aspiration, and acryl lens insertion. PATIENTS AND METHODS: Combined surgery was performed in 316 eyes of 279 patients between 1995 and 1997. Postoperative observation was continued in all of them for more than 6 months. The diagnoses that led to vitrectomy included diabetic retinopathy in 155 eyes, rhegmatogenous retinal detachment in 64 eyes, macular hole in 43 eyes, and other diseases in 93 eyes. The rate of postoperative complications that needed any reoperation was investigated. RESULTS: Reoperations were needed for intravitreal hemorrhage in 23 eyes (7.3%), retinal detachment in 15 eyes (4.7%), rubeotic glaucoma in 6 eyes (1.9%), and other conditions in 4 eyes (1.3%). Among them, reoperations were performed on 13 eyes (4.1%) twice and more. A removal of an intraocular lens was needed in 16 eyes (5.1%) for treatment of vitreoretinal disease. In patients with diabetic retinopathy, reoperations were needed for intravitreal hemorrhage in 21 eyes (13.5%), rubeotic glaucoma in 6 eyes (3.9%), other diseases in 4 eyes (2.6%), and a removal of an intraocular lens was needed in 10 eyes (6.5%) at a higher rate than the other disease. CONCLUSION: This combined surgery is considered advantageous for removing peripheral vitreous, while preventing these complications is important for preserving visual function.

Acrylic Resins↗