Shinobu Awaya

Comparison of Muscle Volume Between Congenital and Acquired Superior Oblique Palsies by Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) studies of superior oblique (SO) muscles have revealed a high incidence of SO muscle atrophy/hypoplasia in congenital SO palsy patients. It has also been reported that long-standing acquired SO palsy patients show atrophic SO muscles in the affected eye. The purpose of this study was to compare the incidence of SO muscle atrophy/hypoplasia in congenital and acquired SO palsy by utilizing MRI. Coronal MRI image planes were taken from 29 cases of unilateral congenital SO palsy and 9 cases of acquired unilateral SO palsy patients. The SO muscle bellies were traced and their sizes were measured from each image plane. The total volume of the affected superior oblique muscle was compared with that of the normal fellow eye. The mean volume of the affected superior oblique muscle to that of the normal muscle was 45.3% (SD = 30.1) in the congenital group and 65.8% (SD = 22.7) in the acquired group. The volume reduction of the SO muscle in congenital SO palsy patients appears to be mainly a congenital abnormality rather than a secondary change, as seen in acquired SO palsy patients.

Treatment of Fungal Corneal Ulcers With Amphotericin B Ointment

PURPOSE To report two patients with severe fungal corneal ulcers who were treated successfully with topical amphotericin B ointment. METHODS Two eyes of two patients developed corneal ulcers and hypopyon after corneal foreign body removal. Aspergillus fumigatus and Fusarium solani were isolated in Patients 1 and 2, respectively. By antifungal susceptibility testing, amphotericin B was shown to have the lowest minimal inhibitory concentration. RESULT Topical administration of amphotericin B ointment resulted in dramatic improvement in fungal corneal ulcers. CONCLUSIONS Antifungal susceptibility tests may aid with selection of antifungal agents. Amphotericin B ointment is one of the promising therapies for keratomycosis caused by antimycotic-resistant fungi.

Type VI collagen bound to collagen fibrils by chondroitin/dermatan sulfate glycosaminoglycan in mouse corneal stroma

We investigated the ultrastructural localization of type VI collagen in mouse corneal stroma and its relationship to striated collagen fibrils and glycosaminoglycans, using chondroitinase ABC digestion and immunoelectron microscopy with colloidal gold particles. After chondroitinase ABC digestion, the arrangement of striated collagen fibrils was disrupted, and large spaces containing widely scattered fibrils appeared. The spaces were filled by filamentous networks that were stained by anti-type VI collagen IgG, which were apparently clumps of beaded filament. Interfibrillar type VI collagen beaded filaments and immunogold particles decreased. Our results indicate that type VI collagen is bound to the striated collagen fibrils by mediation of chrondroitin/dermatan sulfate glycosaminoglycan or proteoglycan. We believe that this interaction is essential to the orderly arrangement of the striated collagen fibrils, which results in corneal transparency.

Fluorescein Angiography of Peripheral Retina and Pars Plana During Vitrectomy for Proliferative Diabetic Retinopathy

PURPOSE To evaluate the extreme peripheral retina and pars plana during vitrectomy in patients with proliferative diabetic retinopathy. METHODS In a prospective study using a modified ophthalmic endoscopic system and an intraocular light source, we performed fluorescein angiography during pars plana vitrectomy in 12 eyes of 10 patients with proliferative diabetic retinopathy. Vitrectomy had been performed previously in two patients, and the subsequent surgery was necessary because of recurrent vitreous hemorrhage in one patient and silicone oil removal in the other. RESULTS All 12 eyes of 10 patients demonstrated a wide avascular area in the peripheral retina anterior to the previous photocoagulation scar. At the ora serrata in two eyes, a fibrovascular ridge of peripheral retinal vessels with fluorescein leakage that resembled the demarcation line in retinopathy of prematurity was noted; one eye had developed neovascular glaucoma 4 weeks after vitrectomy with maximum augmentation of endolaser photocoagulation, and the other eye had neovascular glaucoma that had been treated with photocoagulation 1 year before vitrectomy. In the two eyes that had undergone previous pars plana vitrectomy, fluorescein leakage was apparent at the fibrous scar of the sclerotomy site. CONCLUSION Intraoperative fluorescein angiography using an endoscope disclosed unusual findings in the extreme peripheral retina and pars plana of patients with proliferative diabetic retinopathy. Intraoperative fluorescein angiography may aid intraoperative evaluation and treatment of proliferative diabetic retinopathy.

Form vision deprivation amblyopia: Further observations

Nine cases of esotropia occurring in deprivation amblyopia, where exotropia rather than esotropia is usually found, showed a refractive error of hypermetropia. This fact suggested that an accommodative factor is largely responsible for the development of esotropia. A- or V-pattern strabismus was encountered in a higher incidence in deprivation amblyopia than in ordinary strabismus. Pattern-reversal VEP showed more prominent abnormality than flash VEP did. Studies of the sensitive period of the visual system revealed that the sensitivity is likely to be low for a month or two after birth and increases with a peak around the 18th month of age, decreasing thereafter with a waning slope to the end of the 8th year of life.

Activation of non-selective cation conductance by carbachol in freshly isolated bovine ciliary muscle cells

Abstract In smooth muscle cells freshly isolated from the bovine ciliary body, effects of carbachol (CCh) on the membrane potential and current were examined by the whole-cell clamp method. The resting membrane potential of the muscle cells used was –60 ± 1 mV (n=111). Extracellular application of CCh (2 μM) depolarized the cells to –15 ± 5 mV (n=50) with an apparent increase in membrane conductance. Under voltage-clamp conditions, CCh (2 μM) evoked an inward current which exhibited inward-going rectification and reversed the polarity at about 0 mV. Removal of Na+ from the external solution caused a reduction of the amplitude of the current and a shift of the reversal potential to the negative direction. CCh was able to elicit an inward current even under a condition where Ca2+ was the only cation producing an inwardly directed electrochemical gradient. The current was not affected by verapamil or by tetrodotoxin. The CCh-induced current was inhibited by antimuscarinic agents with the affinity sequence: atropine ≈4–DAMP >> pirenzepine > AF-DX116, indicating that the response is mediated by a muscarinic cholinoceptor that belongs to the M3-subtype. Unlike the non-selective cation channel current in intestinal smooth muscles, which is activated by elevation of the intracellular Ca2+ concentration ([Ca2+]i), the current of the ciliary muscle was inactivated when the [Ca2+]i was increased. The conductance, which admits Ca2+, may serve as a pathway for Ca2+ entry required for contraction.

aniseikonia in patients with a unilateral artificial lens, measured with Aulhorn's phase difference haploscope

Aniseikonia was measured in unilaterally pseudophakic patients using Aulhorns phase difference haploscope. Mean values of aniseikonia were 1.5% horizontally and 2.0% vertically without correction, and 2.1% horizontally and 2.3% vertically with correction. With spectacle correction, the greater the dioptric difference between two eyes, the greater the amount of aniseikonia. In either case, patients tolerated these amounts of aniseikonia according to our criteria of aniseikonia tolerance.

Early retinal involvement in mitochondrial myopathy with mitochondrial DNA deletion.

Background: Mitochondrial DNA (mtDNA) deletions have been reported in types of mitochondrial myopathy, including Kearns-Sayre syndrome (KSS). We examined mtDNA, skeletal muscle findings, and retinal electrophysiologic function in a patient believed to have incomplete KSS with ptosis and characteristic (so called salt and pepper) retinopathy, but without limitation of ocular motility and without other involvement of the central or peripheral nervous system. Methods: Muscle biopsy specimens were examined by Gomori trichrome stain and electron microscopy. DNA extracted from muscle was examined by Southern blot analysis. Deleted mtDNA was sequenced by direct sequencing with polymerase chain reaction (PCR). Electroretinograms (ERG) and electrooculograms (EOG) were performed for electrophysiologic examination of the retina. Results: There were no ragged red fibers in skeletal muscle specimens, although abnormal aggregation of mitochondria was observed on electron microscopic examination. An mtDNA deletion was detected. It spanned 5266-bp between the tRNASer gene and the ND5 gene. Electroretinographic and electrooculographic findings were normal, although extensive involvement of retinal pigment epithelium was observed on ophthalmoscopic examination. Conclusion: Detecting mtDNA deletion is more critical in diagnosing an incomplete phenotype of mitochondrial myopathy than is morphologic examination. We found that ophthalmoscopic fundus abnormalities preceded abnormalities on ERG and EOG.

Identification of anterior uveal tumor border by transscleral transillumination and an ophthalmic endoscope.

PURPOSE To report a method for identifying the borders of anterior uveal tumors in deeply pigmented eyes. METHOD The borders of the anterior uveal tumors were marked by transscleral transillumination with a fiberoptic light and observed from the vitreous cavity using an ophthalmic endoscope. RESULTS The ophthalmic endoscope disclosed a bright orange spot by transscleral transillumination of a normal uvea in deeply pigmented eyes. Two anterior uveal melanomas and one adenocarcinoma of the nonpigmented ciliary epithelium did not transmit light through the tumors. CONCLUSION With an ophthalmic endoscope and transscleral transillumination, the borders of ciliary body tumors can be identified and clearly demarcated, even in deeply pigmented eyes.

Extrafoveal photostress recovery testing with a scanning laser ophthalmoscope

We used a modified photostress recovery test (PSRT) with microperimetry in a scanning laser ophthalmoscope (SLO) to evaluate the extrafoveal region. After the red-target threshold was determined, the retina was bleached with argon green laser illumination. Test spots were presented every 3 seconds at the testing point and subjects indicated when they saw the spot. We determined the recovery time in 17 normal subjects under the following conditions: bleaching times of 10, 20, and 30 seconds; spot intensities of 0, 2, and 4 dB greater than threshold; Goldmann I, II, and III spots; and spot locations 7.5 degrees temporal to, nasal to, above and below the fovea, and at the fovea. We also measured recovery times inside and outside the detachment in 11 patients with central serous chorioretinopathy. Recovery time was correlated with bleaching time and spot intensity, but not with the location of spot size in normal subjects. In patients with chorioretinopathy, the recovery time was longer inside than outside the detachment. This technique is useful for measurement of photostress recovery time at extrafoveal points, and for comparison of times at various testing points. Results in patients with chorioretinopathy suggest that this technique may be useful for studying the pathophysiology in ocular diseases.