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Biomedical subjects

G Ohmi

Publications and source records attributed to G Ohmi.

16 recordsLinked to original sources
PubMed1999

Rod monochromatism and blue cone monochromatism: pupillary, accommodative and convergence reactions to darkness.

PURPOSE: To elucidate the mechanism of paradoxical pupillary constriction to darkness (PPCD) and the clinical characteristics facilitating this phenomenon. METHODS: Six rod monochromats, three blue cone monochromats, with three obligate BCM carriers, and ten age matched controls were studied. Pupillary responses, refractions and eye positions were measured with an infrared refractometer, with and without background room lighting while being simultaneously recorded on VHS (infrared) video tape from onset of darkness. RESULTS: Only rod monochromats displayed typical paradoxical pupillary responses. Blue cone monochromats and obligate BCM carriers showed reduced pupillary contraction, compared to controls, but no paradoxical pupillary reaction. Changes neither in accommodation nor convergence were found during paradoxical pupillary constriction to darkness in our rod monochromats. CONCLUSIONS: Paradoxical pupillary constrictions to darkness were seen in rod monochromats but were found not to be age or gender related. This constriction was accompanied neither by accommodation nor convergence changes. No significant differences in pupillary responses to darkness were observed in BCMs nor their carriers, although pupillary dilation to darkness seemed slightly impaired as compared to normals.

Accommodation, Ocular↗
PubMed1997

Exotropia secondary to vitreous hemorrhage.

BACKGROUND: Diplopia after cataract surgery has been reported by several authors, but diplopia after recovery from vitreous hemorrhage (VH) has not been described. METHODS: We examined eight patients with manifest exotropia and binocular diplopia after recovery from dense VH by vitreous surgery. VH was bilateral in three patients and unilateral in five, and lasted for an average of 7.7 years. RESULTS: Visual acuity before vitrectomy ranged from 20/200 to light perception; that after vitrectomy ranged from 20/20 to 20/60. Exotropia was present in all patients after vitrectomy. Additionally, seven out of eight patients had vertical strabismus with an average deviation of 6 prism diopters (delta). Fusion was confirmed in four patients with an average amplitude of 13 delta. Four patients underwent horizontal strabismus surgery. Fusion was present in two before strabismus surgery and in all four after surgery; however, unstable diplopia persisted in three of the four after surgery. CONCLUSION: Diplopia after vitrectomy for longstanding VH may occur due to fusion impairment comparable to that occasionally seen after surgery for traumatic cataract.

Adolescent↗
PubMed1997

Horizontal transposition of vertical rectus muscles for treatment of excyclotropia.

BACKGROUND: Horizontal transposition of the vertical rectus muscles has been performed for treatment of excyclotropia associated with congenital absence of the superior oblique, and for residual excyclotropia after the Harada-Ito operation. However, the amount of excyclotropia that can be corrected and whether this technique alters the vertical muscle balance is not well known. We report the surgical results of three patients with pure excyclotropia who underwent unilateral one-half tendon width horizontal transpositions of vertical rectus muscles. METHODS: A one-half muscle width temporal transposition of the superior rectus and nasal transposition of the inferior rectus muscles of one eye was performed in three patients with pure excyclotropia and no associated hypertropia. All three had intermittent torsional diplopia before surgery. RESULTS: Postoperatively, excyclotropia decreased significantly in all fields of gaze, with 8 degrees of reduction by synoptophore and 12.3 degrees of reduction by fundus photography on average. There was no associated vertical or horizontal deviation. All three patients reported improvements of cyclofusion. CONCLUSION: One-half muscle width temporal transposition of the superior rectus and nasal transposition of the inferior rectus muscles was effective in ameliorating excyclotropia and corrected subjective complaints without altering vertical muscle balance.

Adult↗
PubMed1997

Retinal function with lens-induced myopia compared with form-deprivation myopia in chicks.

BACKGROUND: The retina is known to be involved in the development of form-deprivation myopia (FDM); however, it is not clear whether the retinal changes that lead to lens-induced myopia (LIM) are the same as those involved in FDM. To gain insight into the retinal mechanism(s) that cause myopia, we investigated differences in the results of electroretinography (ERG) in eyes with FDM and LIM. METHODS: LIM or FDM was induced in chick eyes by placing various powers of spectacles or an occluder over the left eyes of 6-day-old chicks. After 6 days, the spectacles or occluder was removed, refraction and axial length were measured and ERG was performed. Results for eyes treated with spectacles and those treated with occluders were compared. RESULTS: Refraction and axial length changed concomitant with the power of the lens used, but components of the ERG of eyes with LIM were not related to the power of lens added. Refraction and axial lengths of eyes covered with a -16 D lens did not differ from these values in eyes covered with an occluder. The a- and b-waves were also similar for the two groups. However, oscillatory potentials decreased significantly in the chicks with FDM. CONCLUSIONS: Retinal function differs in LIM and FDM, as indicated by differences in the oscillatory potentials. This difference may stem from the fact that in FDM the retinal image is continuously defocused, whereas images are ultimately focused on the retina in LIM.

Animals↗
PubMed1997

The effect of nitric oxide synthase inhibitor on form-deprivation myopia.

PURPOSE: Form-deprivation myopia (FDM) is believed to result principally from actions of substances that modulate information processing in the retina. We used a chick model to investigate what role nitric oxide (NO), a gaseous neuromodulator, might play in the development of FDM. METHODS: We injected different concentrations of the NO synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) (30 ml) into the left eyes and the same volume of saline into the right eyes of 6-day-old chicks. Both eyes of most chicks were occluded for 6 days with translucent goggles. After removal of the goggles, the refraction was measured by retinoscopy and the axial lengths with an A-mode ultrasound. In some chicks we measured the concentration of NOx (nitrite and nitrate) in the retina. A few chicks, not wearing occluders after injection of L-NAME and saline, ERG and refraction, were examined 6 days after the treatment. RESULTS: In chicks that wore occluders, refractive error and axial length were significantly less affected in eyes injected with L-NAME (180, 360, or 540 mM) compared to control (right) eyes. ERG changes were reversible, except in eyes injected with the highest concentration (540 mM) of L-NAME. The eyes of chicks, injected with L-NAME and reared without occlusion, had normal refractive values. After 6 days of form deprivation, the concentration of NOx in the retina of eyes injected with L-NAME (180 mM) was significantly less than the concentration in eyes injected with saline. CONCLUSIONS: The injection of L-NAME before occlusion of developing chick eyes leads to reversible modifications in retinal function and inhibits the development of form-deprivation myopia.

Animals↗
PubMed1997

Value of thyroid stimulating antibody in the diagnosis of thyroid associated ophthalmopathy of euthyroid patients.

AIMS/BACKGROUND: Thyroid associated ophthalmopathy (TAO) of euthyroid patients is difficult to diagnose because clinical findings overlap with other conditions, and no confirmatory diagnostic tests are available. Recently, it was reported that TSH binding inhibitor immunoglobulin (TBII) and thyroid stimulating antibody (TSAb) are sensitive markers of TAO. The sensitivity of these antibodies in the detection of TAO were therefore studied to determine if they could be a useful criterion in the diagnosis of TAO of euthyroid patients. METHODS: Serum values of TBII and TSAb of 35 patients with euthyroid TAO (group A) were compared with those of 27 patients with Graves' disease and TAO (group B). The relation between the serum value of TSAb and the eye symptoms of patients with euthyroid TAO were also examined by multiple linear regression analysis. RESULTS: In group A, TBII was positive in 10 cases (28.6%) and TSAb was positive in 29 cases (82.9%). In group B, both TBII and TSAb were positive in all cases (100%). The titre of serum TBII in group A (15.6% (SD 18.0%)) was significantly lower (p < 0.0001) than in group B (57.9% (21.5%)). The titre of serum TSAb in group A (1400.9% (2163.9%)) was significantly lower (p = 0.0026) than in group B (2243.9% (1472.8%)). Among the eye findings of patients with euthyroid TAO, keratopathy was significantly (p = 0.034) related to the value of TSAb. CONCLUSION: These results suggest that the activity of TSAb is a more sensitive marker of euthyroid TAO than is TBII, and could be a useful criterion in the diagnosis of TAO of euthyroid patients.

Adolescent↗
PubMed1996

A clinical evaluation of stereopsis required to see 3-D images.

Some children with esotropia who have been diagnosed as 'stereoblind' on the basis of conventional stereotests (which principally use static images with small disparity) may nevertheless enjoy stereopsis for three-dimensional (3-D) animations that use dynamic images with large disparity. The purpose of this study was to develop a new stereotest equipped with dynamic random-dot stereogram (DRDS) which has larger disparity with movement and use it with esotropic children to see if they can attain stereopsis for such images. Subjects were 17 esotropic children between 5 and 10 years old (mean age 6.8 years) who had failed to demonstrate stereopsis with the Titmus fly test. Seven children had infantile esotropia and 10 had partially accommodative esotropia. The test images were DRDS that were presented on a fluorescent screen (12 x 9 cm) viewed through a lenticular lens. The dots were displayed in circle and triangle patterns that have counterphase front-rear movement with maximum disparity of 800 s. Patients were placed with eyes at a distance of 60 cm from the screen and were instructed to point out the pattern (circle or triangle) that was produced. The average angle of strabismus was 7.7 delta by alternating prism cover test (5 m). Seven patients passed and 10 failed the DRDS test. There was no significant difference in the mean angle of strabismus or the age of examination between the two groups; however, the age at onset of strabismus was significantly higher in those who passed the DRDS test. These results suggest that the DRDS test is useful in evaluating the potential stereopsis in children with esotropia who do not pass conventional stereotests.

Accommodation, Ocular↗
PubMed1993

Transient hyperopia with lens swelling at initial therapy in diabetes.

The clinical courses of 10 eyes of five diabetic patients who exhibited bilateral transient hyperopia (maximum: 1:1-4.9 dioptres, spherical equivalent) after initiation of strict control of diabetes with or without insulin are reported. The hyperopia occurred within a few days after abrupt decrease in plasma glucose, progressed to maximum at days 7-14, and regressed gradually over 1 month thereafter. Transient cycloplegia had no effect on refractive error. During hyperopia, there were no significant changes in axial length or corneal curvature. However, thickened lens, decreased anterior chamber depth, and transient cataract were observed to significant degrees. It is suggested that the transient hyperopia, with lens swelling and opacity, was caused by decreased lens refractive index following water influx.

Adult↗
PubMed1991

[The effects on accommodative and pupillary responses by topical application of cyclopentolate hydrochloride].

Accommodative and pupillary responses, refractive change, and visual acuity after 30 microliters instillation of cyclopentolate hydrochloride of various concentrations (0.00625-0.1%) in 6 young normal males (27.0 +/- 0.6 yrs) were investigated. Both accommodative and pupillary responses were measured by an infrared optometer, at pre-instillation and 1, 3, 6, 9 and 24 hours post-instillation. No significant effects were induced by concentrations of cyclopentolate hydrochloride 0.0125% or less. Reduced amplitude of accommodation and enlarged pupil were, however, observed by 0.025% and 0.05% of cyclopentolate hydrochloride from 1 through 9 hours post-instillation. Miotic response in accommodation was also reduced from 1-6 hours at the same concentrations. A concentration of 0.1% cyclopentolate hydrochloride showed both reduction of accommodation amplitude and enlarged pupil for 24 hours after instillation. However, neither refraction nor visual acuity was affected by any concentration of cyclopentolate hydrochloride. The results suggest that cyclopentolate hydrochloride at concentrations up to 0.05% applied before sleep would not be accompanied by inhibitory effects on accommodation during the day.

Accommodation, Ocular↗
PubMed1991

[The aging of accommodative function and its pupillary response in VDT workers without subjective complaints].

Using a computer-assisted infrared optometer with a pupillometer, we measured the accommodative function and its pupillary response in 81 female subjects (age: 31-55 yrs) without visual complaints who worked via visual-display-terminal (VDT). From these measurements we analyzed the following 6 parameters regarding accommodation, and investigated whether a correlation exists between age and each parameter. The six parameters were, (1) the amplitude of objective accommodation, (2) the refractive fluctuation at the resting state of accommodation, (3) the refractive fluctuation after receiving myopic stimuli, (4) the pupil area prior to myopic stimuli, (5) the maximum rate of constriction by accommodation, and (6) the rate of pupil area recovery after accommodation. Among these parameters, the amplitude of objective accommodation, the refractive fluctuation at the resting state of accommodation, the refractive fluctuation after receiving myopic stimuli, and the pupil area prior to myopic stimuli were significantly correlated with age (all parameters: p less than 0.001). The correlation coefficients (r) were -0.810, -0.591, -0.612 and -0.320 respectively. There was also some relationship between age and the rate of pupil area recovery after accommodation (r = 0.188, p = 0.018), but no statistically significant correlation between age and the rate of constriction by accommodation (r = 0.100). These findings suggest that the overall functional capability of accommodation decreases constantly with age, though the pupillary reaction induced by accommodation is not correlated well with age.

Accommodation, Ocular↗
PubMed1990

[Insufficient accommodation in patient with keratoconus].

The accommodation response in 10 unoperated patients with keratoconus (mean, 28.3 years) and 10 age-matched normal individuals (mean, 25.8 years) was examined. Using infrared high-speed optometer and iriscorder, quasistatic accommodation and concomitant pupillary response were simultaneously measured by controlling a fixation target for accommodation with a microcomputer. The amplitude of the accommodation response was markedly lower in patients with keratoconus (2.8 +/- 1.4 Diopter) than in controls (4.7 +/- 1.3 Diopter: p less than 0.005). The maximum pupillary responses during far to near accommodation was also significantly decreased in the keratoconus group (0.25 +/- 0.24) when compared with controls (0.56 +/- 0.15; p less than 0.001), despite no statistical difference in pupillary size in the far point between the two groups. The above two pathologic parameters were not found to correlate with the severity of keratoconus. These results suggest that some predisposing abnormalities may exist in the iris and ciliary body of patients with keratoconus, which may be responsible for a paretic pupil that occasionally occurs after corneal transplantation in these patients.

Accommodation, Ocular↗
PubMed1987

Goblet cell density in thermal and chemical injuries.

Abnormality of the conjunctival epithelium was evaluated in ten patients with severe thermal and chemical injuries at the scarred stage, eight patients with Stevens-Johnson syndrome, five with cicatricial ocular pemphigoid, and 13 normal subjects, based on goblet cell densities obtained using impression cytologic examination. The average and SDs of goblet cell densities were 197.4 +/- 264.4/mm2 in thermal and chemical injuries, 3.0 +/- 5.6/mm2 in Stevens-Johnson syndrome, 0.6 +/- 0.8/mm2 in cicatricial ocular pemphigoid, and 38.7 +/- 25.8/mm2 in normal subjects. There were statistically significant differences in goblet cell densities between thermal and chemical injuries and both Stevens-Johnson syndrome and cicatricial ocular pemphigoid. Moreover, conjunctival specimens from both eyes in six unilateral cases of thermal and chemical injuries revealed higher goblet cell densities in the injured than in the normal fellow eyes in all cases. These findings imply that ocular surface diseases with similar clinical manifestations may have different cell-biologic abnormalities in the conjunctival epithelium.

Burns, Chemical↗
PubMedDate not supplied

Use of dynamic and colored stereogram to measure stereopsis in strabismic patients.

The effectiveness of movement or color has not been well studied in assessing stereopsis in patients with strabismus. We developed a new stereotest equipped with both a monochromatic dynamic random dot stereogram (DRDS) and a static-colored stereogram (SCS) and examined the stereopsis of patients with strabismus. Three-dimensional (3D) images were displayed on a liquid crystal display equipped with a parallax barrier system, allowing 3D images to be seen independently by each eye without glasses. A DRDS with maximum disparity of 3200 seconds of arc was displayed having front-rear movement. An SCS displaying cartoon characters with disparities of 400 seconds of arc was also tested and compared with the Titmus stereotest. A total of 52 strabismic patients were tested. The DRDS showed a significantly higher (P = 0.02) detection rate of stereopsis (39/52, 75%) as compared with the Titmus fly test (28/52, 54%). The SCS did not show any difference in the stereopsis detection rate (24/521, 46%) when compared with the Titmus animal test (20/52, 38%). Thus, the DRDS was useful in detecting stereopsis in patients without stereopsis on the conventional Titmus fly test, while the SCS did not show any difference when compared with the Titmus animal test. The DRDS may examine a different aspect of stereopsis from the static stereopsis measured by the Titmus stereotest or SCS.

Adolescent↗
PubMedDate not supplied

Strabismus surgery using the intraoperative adjustable suture method under anesthesia with propofol.

PURPOSE: To evaluate the feasibility and efficacy of using the intraoperative adjustable suture method with anesthesia induced by intravenously administered propofol for strabismus surgery. METHODS: Seven adult patients (mean age, 29.7 +/- 18.5 years) with different types of strabismus were enrolled in this study. All patients underwent full ophthalmological and general medical examinations before surgery. Surgery was performed after induction of anesthesia using intravenously administered propofol that was titrated to control consciousness. RESULTS: Arousal of consciousness was observed at approximately 2 minutes after discontinuation of the propofol infusion in each case, and the consciousness level was sufficient to allow accurate cover-uncover testing and intraoperative adjustment of sutures. Minor complications of nausea in three patients and vomiting in one patient were noted after surgery. CONCLUSIONS: Strabismus surgery using the adjustable suture method with propofol intravenous anesthesia appears to be safe and useful for the treatment of adult strabismus.

Adult↗