Yutaka Tazawa

Multicenter Clinical Trial for Evaluating Methylprednisolone Pulse Treatment of Idiopathic Optic Neuritis in Japan

BACKGROUND A randomized, controlled clinical trial was conducted in 1991 to compare an intravenous megadose of methylprednisolone with a control drug (mecobalamin) for treating acute idiopathic optic neuritis. CASES Sixty-six cases from 22 clinical centers throughout Japan were examined to evaluate the treatment on visual function parameters, such as visual acuity, visual field, color vision, contrast sensitivity, and critical flicker frequency. OBSERVATIONS The methylprednisolone pulse treatment group showed faster recovery of visual function, particularly the visual acuity at 1 week (P<.05), Humphrey field analyzer mean deviation at 3 weeks (P<.05), and color vision at 1 week (P<.05). Recovery of contrast sensitivity at several different spatial frequencies was significant in the pulse treatment group at 1 (P<.01), 2 (P<.05), and 4 weeks (P<.05) after the start of treatment. Visual function test results at 12 weeks and 1 year were essentially the same in the two treatment groups. Side effects appeared more frequently in the pulse treatment group than in the control (P<.05). CONCLUSIONS Pulse treatment does not appear effective for idiopathic optic neuritis even though visual function in the pulse treatment group of this trial recovered more quickly during the initial phase compared to the controls. More effective and specific treatment should be established for optic neuritis.

Refractive results of post penetrating keratoplasty photorefractive keratectomy.

BACKGROUND AND OBJECTIVE The aim of this study was to evaluate the safety, effectiveness, and predictability of photorefractive keratectomy (PRK) for severe myopia and astigmatism following penetrating keratoplasty. PATIENTS AND METHODS PRK was performed on 42 eyes, and 33 eyes were followed up for at least 6 months. RESULTS Mean preoperative spherical equivalent was -8.29 +/- 4.01 diopters (D), which decreased to -2.96 +/- 3.26 D in manifest refraction at 6 months. Keratometric power reduced from 48.06 +/- 3.32 D preoperatively to 43.97 +/- 3.40 D. Refractive and keratometric astigmatism attained the reduction of 31.0% and 13.56% in average respectively. Twenty three eyes had improved uncorrected visual acuity. CONCLUSION PRK was effective in reducing post-keratoplasty myopia and astigmatism, but the predictability was not as good as in the non-grafted eye.

Correlation of retinal function with retinal histopathology following ischemia-reperfusion in rat eyes

Purpose. To investigate the relationship between retinal function and histopathology following retinal ischemia-reperfusion in rats. Methods. Retinal ischemia was induced in 27 Sprague-Dawley rats by raising the intraocular pressure for 60- or 90-minutes. Two weeks after the retinal ischemia-reperfusion, ganzfeld stimuli of different luminances (maximum 0.51 log cd-s/m2) were used to elicit full-field ERGs from the right (experimental) and left (control) eyes. The amplitudes of the scotopic b-waves were measured, and intensity-response curves were plotted. The b-wave amplitudes at the initial peak (VbIP), the dip (Vbdip), and the maximum stimulus intensity (Vbmax) were measured. The animals were sacrificed after the ERG recordings to determine the surviving retinal cells in the inner nuclear layer (INL). Results. The log values of the VbIP, Vbdip and Vbmax were linearly correlated with the number of surviving cells in the INL (r = 0.928, 0.905, and 0.913 for VbIP, Vbdip and Vbmax, respectively; p < 0.0001 for each). The slope of the regression line for the Vbdip was significantly steeper than that for the VbIP and Vbmax (p < 0.005). The regression line for the Vbdip reached undetectable level of the b-wave (<1 µV) even though approximately 25% of the cells still remained in the INL. Conclusions. The amplitude of the scotopic b-wave is a sensitive index of the surviving INL cells. However, if one selects the stimulus intensity at the dip, the functional loss would be exaggerated in spite of the presence of cells in the INL.

Observation of the ocular fundus by an infrared-sensitive video camera after vitreoretinal surgery assisted by indocyanine green.

Purpose To investigate how long indocyanine green (ICG) dye remains in the ocular fundus and how the remaining dye interferes with ICG angiographic findings after vitreoretinal surgery assisted by ICG. Methods Eight eyes with macular hole, three with epiretinal membrane, and one with an intraocular foreign body were included. Those patients underwent vitrectomy facilitated by an intraocular administration of ICG. An infrared sensitive video camera was used to take fundus pictures pre- and postoperatively. In 2 of 12 cases, the authors performed ICG angiography at 2 weeks and at 3 months after the surgery. Results At 1 month after surgery, diffuse hyperfluorescence was observed throughout the posterior pole of the ocular fundus in all cases. The area where macular hole existed before the surgeries revealed hyperfluorescence in 6 of 8 eyes with macular hole (75%). These hyperfluorescent findings became less prominent with time postoperatively, while optic disk hyperfluorescence persisted for 12 months in all cases. In the early phase of ICG angiography at 2 weeks postoperatively, the retinal and choroidal circulation could be depicted. However, in the middle phase the choroidal veins were hardly visible. The angiographic pictures of the late phase mimicked those seen without intravascular administration of ICG. Even at 3 months after surgery, the optic nerve head revealed hyperfluorescence in the middle and late phases. Conclusions The residual ICG in the ocular fundus produced prolonged hyperfluorescence after surgery. This abnormal condition affected ICG angiographic findings in the middle and late phases.

Effects of Aging on the First and Second-order Kernels of Multifocal Electroretinogram

PURPOSE To determine the effects of aging on the first and second-order kernels of the multifocal electroretinogram (ERG). METHODS Multifocal ERGs were recorded from 52 healthy subjects (52 eyes) (0 >or= refractive error >or= -3.0 diopter). The ages of the subjects ranged from 12-76 years with a mean (+/-SD) of 44.0 +/- 20.2 years. The Visual Evoked Response Imaging System was used. The effects of aging on the response densities and on the implicit times of the first positive wave (P1) of the first-order kernel, and of the second and third positive waves (P2 and P3) of the second-order kernel were analyzed for the different age groups. RESULTS The response densities of the first-order kernel P1 and second-order kernel P2 waves decreased significantly, and the implicit times of the second-order kernel P2, and P3 were significantly prolonged (P <.05) in subjects over 50 years of age. CONCLUSION The results suggest that the age of the subject should be considered when evaluating retinal function using multifocal ERGs in basic and clinical studies.

Changes in the shape of the anterior and posterior corneal surfaces caused by mydriasis and miosis: detailed analysis.

Purpose: To evaluate changes in the anterior and posterior corneal shape, corneal thickness, and anterior chamber depth (ACD) caused by mydriasis or miosis using scanning‐slit corneal topography. Setting: Department of Ophthalmology, Iwate Medical University School of Medicine, Iwate, Morioka, Japan. Methods: Twenty‐eight eyes of 28 healthy volunteers with refractive errors of −6.00 to +0.25 diopters were studied. One eye of each subject had instillation of tropicamide–phenylephrine hydrochloride (Mydrin P®) to obtain mydriasis and of pilocarpine hydrochloride 2% (Sanpilo®) to obtain miosis. To assess the corneal shape, the best‐fit sphere (BFS), axial power, and tangential power were measured for the anterior and posterior corneal surfaces before and after mydriasis and before and after miosis using scanning‐slit corneal topography (Orbscan version 3.0, Orbtek, Inc.). The pupil size, corneal thickness, and ACD were also examined before and after mydriasis and before and after miosis. Results: The mean age of the patients was 31.1 years ± 5.6 (SD) (range 20 to 46 years). The anterior BFS changed from a mean of 8.04 ± 0.3 mm at the time of mydriasis to a mean of 8.00 ± 0.3 mm at the time of miosis. The posterior BFS changed from 6.53 ± 0.3 mm to 6.46 ± 0.3 mm, respectively. Thus, the anterior and posterior cornea became significantly steeper after miosis (P<.01). The ACD was significantly more shallow after miosis than after mydriasis. However, there was no significant difference in corneal thickness after mydriasis or miosis. Conclusions: The anterior and posterior corneal shapes changed as a result of mydriasis and miosis, and the refractive power of the cornea significantly increased after miosis. To date, changes in refractive power from changes in pupil size have been attributed to a change in the refractive power of the crystalline lens; however, it is now thought that changes in corneal refractive power also occur.

Projections of extraocular muscle primary afferent neurons to the trigeminal sensory complex in the cat as studied with the transganglionic transport of horseradish peroxidase

The central projections of extraocular muscle primary afferent neurons were examined in the cat by means of transganglionic axonal transport of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP). Injections of the extraocular muscle with WGA-HRP resulted in transganglionic terminal labeling within the ipsilateral trigeminal sensory complex. Although the density of trigeminal projections varied among cases, labeled axons and terminals were heavily and consistently found within the rostroventral portion of the pars oralis of the spinal trigeminal nucleus. The caudal part of the trigeminal principal sensory nucleus occasionally contained moderate labeling but very few deposits of HRP reaction product were noted in the pars interporalis and pars caudalis of the spinal trigeminal nucleus.

Third-order neuronal responses contribute to shaping the negative electroretinogram in sodium iodate-treated rats.

Purpose: To determine possible mechanisms that shape the negative electroretinograms (ERGs) in rats with photoreceptor degeneration induced by destruction of the retinal pigment epithelium. Methods: Sprague-Dawley rats (n = 48) were injected intravenously with 60 mg/kg of sodium iodate (NaIO3). Full-field ERGs were elicited by different stimulus intensities with a maximum luminance of 1.23 log cd-s/m2 and recorded at 6 hr and on days 7, 14, and 28 after the NaIO3 injections. DL-2-amino-4-phosphonobutyric acid (APB, 1 mM) or N-methyl-L-aspartic acid (NMDA, 5 mM) was injected into the vitreous cavity to isolate photoreceptor (PIII), second-order, and third-order neuronal responses. After recording the ERGs, animals were sacrificed for histological analysis. Results: Negative ERGs were recorded under scotopic conditions on day 7 after the NaIO3 injection. An intravitreal injection of NMDA eliminated most of the a-wave, resulting in the abolition of the negative ERG. On days 14 and 28, the a-wave amplitudes were reduced compared to those on day 7 with the loss of the negative ERGs. The mean amplitudes of the PIII and second-order neuronal responses were progressively reduced until day 7. In contrast, the mean amplitude of the third-order neuronal responses were relatively well-preserved until day 7 and then were decreased between days 7 and 14. As a result, the amplitude of the third-order neuronal response dominated over the second-order neuronal response on day 7. There was no significant difference in the middle and inner retinal morphology at each time point. Conclusions: NaIO3 produced negative ERGs transiently, and the third-order neuronal responses were the main contributors to the negative ERG. The relative preservation of the third-order neuronal response plays a role in shaping the negative ERGs in this model.

Adult T-cell leukemia with leukemic cell infiltration in the conjunctiva

A 77-year-old Japanese woman who had suffered from skin eruptions since 1986 was admitted in January, 1990. A diagnosis of adult T-cell leukemia/lymphoma (ATL) was made on the basis of clinical and laboratory data. On admission, erythematous lesions were present in both eyelids. Yellowish-white elevated lesions were found along the limbal conjunctiva, and extended segmentally into the cornea of both eyes. Microscopically, leukemic infiltration into the subepithelial layer of the conjunctiva was observed. Ophthalmic manifestations in ATL have not been well described, because of a little attention paid to them.

Choroidal Circulatory Disturbance in Ocular Sarcoidosis Without the Appearance of Retinal Lesions or Loss of Visual Function

BackgroundBirdshot chorioretinopathy, acute posterior multifocal placoid pigment epitheliopathy, and retinal pigment epithelial detachment have been reported as rare manifestations associated with sarcoidosis, suggesting that ocular sarcoidosis may affect the choroidal circulation. We report a case of ocular sarcoidosis representing a choroidal circulatory disturbance without the appearance of retinal lesions or loss of retinal function.CaseA 20-year-old woman was referred with blurred vision in the left eye. Inflammatory change in the anterior segment of the eye was noted with multiple nodules on the iris.ObservationsHematological examination revealed elevated lysozyme levels. Bilateral hilar lymphadenopathy was noted on chest X-ray. Specimens obtained by transbronchial lung biopsy revealed granuloma with Langhans giant cells, which led to the diagnosis of sarcoidosis. The eye was treated with topical steroid. The symptoms and the inflammatory change in the anterior segment disappeared within 10 days. However, despite the normal appearance of the ocular fundus, fluorescein angiography revealed multiple puncta of hyperfluorescence. In indocyanine green angiography, a filling delay was noted in the area corresponding to the punctate lesions. Static visual field testing and multifocal electroretinography showed no significant changes. At the last visit, 15 months after the left eye became asymptomatic, the choroidal lesions had disappeared with no residual alteration of the funduscopic appearance or visual function.ConclusionsThis case indicates that choroidal circulatory disturbance can underlie ocular sarcoidosis even in the absence of funduscopically detectable lesions and loss of visual function.