Sachiko Hommura

Refractive changes in diabetic patients during intensive glycaemic control.

AIMS To evaluate the clinical course and the characteristics of transient refractive error occurring during intensive glycaemic control of severe hyperglycaemia. METHODS 28 eyes of patients with persistent diabetes were included in this prospective study. During the observation period, patients underwent general ophthalmological examination and A-mode scan ultrasonography was performed at each examination—at days 1, 3, and 7, and then once every week or every other week until recovery of hyperopia. RESULTS A transient hyperopic change occurred in all patients receiving improved control after hyperglycaemia. Hyperopic change developed a mean of 3.4 (SD 2.0) days after the onset of treatment, and reached a peak at 10.3 (6.1) days, where the maximum hyperopic change in an eye was 1.47 (0.87) D (range 0.50–3.75 D). Recovery of the previous refraction occurred between 14 and 84 days after the initial assessment. There was a positive correlation between the magnitude of the maximum hyperopic change and (1) the plasma glucose concentration on admission (p<0.01), (2) the HbA1c level on admission (p<0.005), (3) the daily rate of plasma glucose reduction over the first 7 days of treatment (p<0.001), (4) the number of days required for hyperopia to reach its peak (p<0.001), and (5) the number of days required for the development and resolution of hyperopic changes (p<0.0001). There was a negative correlation between the maximum hyperopic change of an eye and baseline value of refraction (p<0.01). During transient hyperopia, no significant changes were observed in the radius of the anterior corneal curvature, axial length, lens thickness, or depth of anterior chamber. CONCLUSIONS The degree of transient hyperopia associated with rapid correction of hyperglycaemia is highly dependent on the rate of reduction of the plasma glucose level. A reduction of refractive index in intraocular tissues, especially in lens, appears to be responsible for this hyperopic change.

Oral Itraconazole and Topical Miconazole With Debridement for Acanthamoeba Keratitis

We treated three patients who had Acanthamoeba keratitis with oral itraconazole, a new antifungal agent, topical miconazole, and surgical débridement of the lesion. In these patients, healing and regression of the keratitis began six or seven days after initiation of oral itraconazole and miconazole 0.1% eyedrops (every hour during the day). The clinical signs of corneal infection disappeared after nine weeks in Patient 1, after five weeks in Patient 2, and after eight weeks in Patient 3. Visual acuities improved markedly from hand motions to 20/30 in Patient 1, from counting fingers to 20/16 in Patient 2, and from hand motions to 20/40 in Patient 3. In these patients, no systemic or topical signs of toxicity or adverse reactions were noted during the course of treatment.

A new model of transient complete obstruction of retinal vessels induced by endothelin-1 injection into the posterior vitreous body in rabbits

Endothelin-1 (ET-1) is a potent vasoconstrictor peptide produced by vascular endothelial cells. In order to investigate the effects of ET-1 on retinal vessels, ET-1 (1 ∼ 1000 pmol) was injected into the posterior vitreous body in rabbits. A high dose of ET-1 induced transient complete obstruction of the retinal vessels. In this experimental model of transient complete obstruction of the retinal vessels, the effects of ET-1 on retinal function were further analyzed by means of electroretinograms. The scotopic a-wave was not affected, but the amplitude of the scotopic b-wave was significantly elevated. The amplitude of oscillatory potentials was significantly reduced. These phenomena suggested that retinal ischemia without choroidal ischemia was brought about due to severe vasoconstriction of the retinal arteries. These findings indicate that intravitreal injection of ET-1 causes a transient cessation of blood supply from retinal vessels and that oscillatory potentials in electroretinograms appear to be sensitive for detecting changes of retinal circulation. This new model of transient complete obstruction of retinal vessels might be useful for studying the pathophysiology of severe retinal ischemia.

Frequency of glutathione-S-transferase 1 gene deletion and its possible correlation with cataract formation.

This experiment was conducted to investigate the possible association between an increased frequency of glutathione-S-transferase (GST)1 gene deletion and the presence of cataracts in elderly patients. Genomic DNA was isolated from blood samples obtained from 138 elderly patients who had undergone cataract surgery, and from 62 random blood donors. All subjects lived in the same geographic area (Ibaraki Prefecture, Japan). The DNA sequences among three different exon ranges (exons 3-5, exons 4-5 and exons 5-6) of the GST1 gene were amplified by the polymerase chain reaction (PCR) technique to determine if GST1 gene deletion occurred. Cataract patients had a significantly higher frequency of GST1 gene deletion than random controls did (P < 0.001, odds ratio = 2.91, 1.56-5.44; 95% of confidence interval). Mean age of cataract patients lacking GST1 gene was significantly younger (n = 101, mean age = 70.4, s.d. = 10.2) than that of patients possessing the GST1 gene (n = 37, mean age = 75.0, s.d. = 8.7) (P < 0.02). These results show that the deletion of the GST1 gene may be one of determinants of genetic susceptibility to cataractgenic agents.

Direct Examination vs Culture of Biopsy Specimens for the Diagnosis of Keratomycosis

In two patients with fungal keratitis, direct examination of corneal biopsy specimens showed positive fungal elements, but cultures of biopsy specimens failed to disclose fungal growth. We compared the value of direct examination and culture of biopsy specimens in the diagnosis of keratomycosis in rabbits with experimental fungal keratitis caused by Fusarium solani, Aspergillus fumigatus, and Candida albicans. Cultures disclosed seven specimens (70%) positive for Candida and eight (80%) for Fusarium and Aspergillus keratitis, whereas direct examination showed positive fungal elements of Fusarium, Aspergillus, and Candida in all specimens.

Up-regulation of Hrk, a regulator of cell death, in retinal ganglion cells of axotomized rat retina.

Hrk, a regulator of cell death, belongs to the family of pro-apoptotic BH3-only proteins and is known to induce apoptosis in nerve tissue. We examined Hrk gene expression to clarify the role of BH3-only proteins in apoptosis of retinal ganglion cells (RGCs) after optic nerve transection in the adult rat. Reverse transcription-polymerase chain reaction showed that Hrk was up-regulated in retina from 12 h after axotomy, and continued to be elevated for 1 week. In situ hybridization histochemistry revealed that Hrk was expressed in a sub-population of axotomized RGCs. These results suggest that Hrk is involved in the induction of apoptosis in RGCs after optic nerve transection.

Mirror Image Myopic Anisometropia in Two Pairs of Monozygotic Twins

Two sets of monozygotic twins with mirror image myopic anisometropia are reported. The first set were two boys aged 1 year 8 months. There was a right eye myopic anisometropia in one twin, and a left eye myopic anisometropia in the other. The differences in refractive power between both eyes were 11.6 and 7.6 dpt, respectively (spherical equivalent). The second set were two 6-year-old boys. The right eye had myopic anisometropia in one twin, while the left eye was affected in the other. The differences in refractive power between both eyes were 6.5 and 3.7 dpt, respectively (spherical equivalent). Exotropia was recognized in 3 cases. Previously only two sets of monozygotic twins with mirror image myopic anisometropia have been reported. Monozygotic twins with mirror image myopic anisometropia are extremely rare.

Measurement of axial length of eyes with incomplete filling of silicone oil in the vitreous cavity using x ray computed tomography

Aims: To establish a reliable method for measuring the axial length of the eye with incomplete filling of silicone oil in the vitreous cavity in order to determine the IOL power before executing combined cataract surgery and silicone oil removal. Methods: 12 eyes of 12 patients undergoing combined cataract extraction and silicone oil removal between October 1998 and June 2000 were entered prospectively into this study. All eyes were examined using an x ray computed tomography (CT) scanner. Each axial length of a silicone oil injected eye was measured on the best CT slice among eyeball cuts, which showed both the insertions of the medial and lateral rectus muscle, the thickest slice of the lens, and the optic nerve. The IOL power for the eyes was determined using the SRK/T formula based on the CT data. The deviation of postoperative refraction from the goal refraction was evaluated for each eye. Results: The CT slices demonstrated that the vitreous cavity was not completely filled with the oil in all of the silicone oil injected eyes. The deviation of postoperative refraction from the goal refraction was less than 1 dioptre (D) error in six of 12 eyes (50%), and was less than 2 D error in nine eyes (75%). In the other three eyes having more than 2 D error, the axial length was 27 mm or more. Conclusion: The CT measurement of axial eye length for determining IOL might be a useful method for evaluating silicone oil injected eyes before combined cataract surgery and silicone oil removal.

Corneal Endothelial Changes and Aqueous Flare Intensity in Pseudoexfoliation Syndrome

Purpose: To determine the changes of corneal endothelium in pseudoexfoliation (PEX) syndrome and the relations between their changes and aqueous flare intensity. Methods: 26 eyes with PEX syndrome, 17 clinically unaffected fellow eyes and 27 normal age-matched eyes were studied. The corneal endothelium of the eyes was examined using a specular microscope, and the aqueous flare intensity of the eyes was measured using a laser flare cell meter. Results: The corneal endothelial density significantly decreased both in the eyes with PEX and in the clinically unaffected fellow eyes compared to the normal control eyes (p < 0.001, p < 0.01). The acqueous flare intensity significantly increased in PEX syndrome (p < 0.01). There was a significantly inverse correlation between the corneal endothelial cell density and the aqueous flare intensity in PEX. Conclusion: A decrease in corneal endothelial cells was quantitatively identified in PEX syndrome. This change might have a relationship with a disorder of the blood-aqueous barrier in this syndrome.

Successful Treatment of a Senile Diabetic Woman with Cataract with Goshajinkigan

A 65-year-old woman with diabetes mellitus (DM) and suffering a cataract in the left eye, that was resistant to Western medical treatment, was treated with goshajinkigan (GJ), a herbal medicinal drug, in combination with eye drops. This treatment remarkably improved the visual disturbance due to the senile cataract. Ten days after commencement of the GJ treatment, her visual acuity did not deteriorate any further. There was also no further deterioration of DM condition. These results suggest that GJ may be valuable in the treatment of diabetic women with cataracts.