Yukihiro Matsumoto

Levels of mature cross-links and advanced glycation end product cross-links in human vitreous.

PURPOSE To determine the levels of pyridinoline and deoxypyridinoline, two mature enzymatic cross-links, and pentosidine, an advanced glycation end product (AGE) cross-link, in human vitreous and to investigate the correlations among the cross-links and the effects of aging and diabetes mellitus (DM) on the levels of the cross-links. METHODS Forty-five vitreous samples were collected from 32 eyes undergoing vitrectomy for diabetic retinopathy (DM group) and 13 eyes (control group) from age- and sex-matched patients with idiopathic macular hole or epiretinal membrane with no systemic conditions. The levels of the cross-links were determined using high-performance liquid chromatography after acid hydrolysis and pre-treatment with SP-Sephadex. RESULTS The levels of pentosidine, pyridinoline, and deoxypyridinoline were 27.3 +/- 23.1(mean +/- standrard deviation) pmol/ml (n = 45), 79.0 +/- 40.2 (mean +/- standrard deviation) ng/ml (n = 43), and 54.0 +/- 9.5 ng/ml (n = 32), respectively. When the vitreous samples from DM and the controls were compared, a significant difference (p < 0.05) was found in the level of pentosidine but not in the levels of pyridinoline or deoxypyridinoline. No significant correlations were found between age and the cross-links. Significant correlations (p < 0.01) were found among the cross-links. CONCLUSIONS The results indicate that mature cross-link substances exist in human vitreous. The results also suggest that glycation may occur in the vitreous after mature cross-links form and result in the formation of AGE cross-links. In human vitreous from patients with DM, increased levels of AGE cross-links may stabilize the formation of mature cross-links but did not increase mature cross-links.

A retrospective study of nine cases of Acanthamoeba keratitis.

Purpose To evaluate the clinical features of Acanthamoeba keratitis in nine patients diagnosed at Dokkyo Medical University Koshigaya Hospital, Saitama, Japan. Methods In nine eyes of nine patients, Acanthamoeba keratitis was diagnosed by direct light microscopy of corneal scrapings stained by the Parker ink-potassium hydroxide method between September 2006 and September 2009. Their clinical features and course were studied retrospectively. Antifungal eye drops, systemic antifungal therapy, and surgical debridement of the corneal lesions were performed in all patients. Results At presentation, the clinical stage was initial in six cases, transient in one case, and complete in two cases. The patients were all contact lens wearers who had washed their lens storage cases with tap water. After treatment, final visual acuity was improved in six cases, unchanged in one case, and worse in two cases. The patient with the worst final vision (hand motion) had rheumatoid arthritis and was taking oral prednisolone, which led to corneal perforation and prevented adequate debridement from being done. Conclusion Acanthamoeba keratitis is closely related to wearing contact lenses and washing the lens storage case with tap water. Although final visual acuity improved after treatment in most patients, insufficient surgical debridement resulted in a poor visual prognosis.

Free radicals in the aqueous humor of patients with glaucoma

Purpose: To clarify the presence of oxidative stress in glaucoma and discuss whether free radicals contribute to neovascular glaucoma (NVG) and non-NVG. Methods: Two patient groups were formed: the NVG group (n = 10) and the non-NVG group (n = 17). Free radicals in aqueous humor were detected by measuring the electron spin resonance (ESR). To identify free radical species, either superoxide dismutase (SOD) or catalase was added to the aqueous humor and compared with aqueous humor in which SOD or catalase was not added. Results: In the NVG group, free radical waveforms were detected that differed from ascorbate-free radical (AFR) in all cases. Under SOD was added, the characteristic waveforms disappeared and the AFR of a specific waveform appeared. After catalase was added, the waveforms were unchanged. In the non-NVG group, the AFR of specific waveforms were detected in all cases. In 4 cases, the waveforms detected the presence of a trace of superoxide. Conclusions: In the NVG group, superoxides were detected, suggesting that superoxide scavenging activity was decreased markedly. L-ascorbic acid likely has an antioxidative function in the non-NVG group, suggesting that the aqueous humor in the NVG group was under higher oxidative stress compared with the non-NVG group.

A case of radial keratoneuritis in non-Acanthamoeba keratitis

A case of non-Acanthamoeba keratitis with radial keratoneuritis, which is thought to be pathognomonic for Acanthamoeba keratitis, is reported. A healthy 32-year-old woman with a history of frequent replacement of her contact lenses due to wear was examined at Dokkyo Medical University Koshigaya Hospital (Saitama, Japan) and found to have a slight corneal opacity that was accompanied by radial keratoneuritis. Based on both the patient’s clinical findings and past history, the presence of Acanthamoeba keratitis was highly suspected. However, direct light microscopy of corneal scrapings stained by the Parker ink–potassium hydroxide method only found Acanthamoeba-type material in the specimen collected at her initial visit. In all other specimens collected from the patient, no Acanthamoeba was found either when using the same method or when performing cultures of the surgical debridement of the corneal lesion. In addition, topical antifungal eye drops, systemic antifungal drugs, and surgical debridement were also not effective in this case. Since a precise diagnosis could not be made, the patient was treated with topical 0.1% betamethasone sodium, which ultimately resulted in a dramatic improvement of her corneal inflammation. At 23 days after initiation of topical administration of 0.1% betamethasone sodium, visual acuity was 20/250, with a slight corneal opacity noted at the original site of infection. The outcome of the current case suggests that radial keratoneuritis is not always pathognomonic for Acanthamoeba keratitis.

Scleral fixation of foldable acrylic intraocular lenses in aphakic post-vitrectomy eyes

Purpose To evaluate the outcome for scleral fixation of a foldable acrylic intraocular lens (IOL) in aphakic post-pars plana vitrectomy eyes for vitreoretinal disease. Methods The medical records of 15 patients were reviewed. We evaluated such factors as the underlying vitreoretinal disease, preoperative expected refraction and postoperative actual refraction, best corrected visual acuity (BCVA), corneal endothelial cell density, and intraoperative and postoperative complications. Results The most common cause of underlying vitreoretinal disease was retinal detachment, which was found in 8 cases. The mean refractive error was −0.10 diopters (D). The mean minimum angle of resolution (logMAR) values of BCVA were 0.27 preoperatively and 0.14 postoperatively. The mean corneal endothelial cell density was 2400 cells/mm2 preoperatively and 2187 cells/mm2 postoperatively. No significant differences were observed in either the logMAR values of BCVA or the corneal endothelial cell density before and after surgery. No intraoperative complications occurred in any of the patients. Postoperative complications occurred in a total of 7 eyes, and the most severe complications comprised 4 cases of transient ocular hypertension. Conclusion The results for the scleral fixation of foldable acrylic IOLs were good in aphakic post-vitrectomy eyes.

Correlation between the matrix metalloproteinase-9 activity and chondroitin sulfate concentrations in tear fluid after laser in situ keratomileusis.

Aims: The aim of the present study was to evaluate the correlation between matrix metalloproteinase-9 (MMP-9) and chondroitin sulfate (CS) concentrations in human tear fluid following laser in situ keratomileusis (LASIK). Methods: Twelve eyes from six patients who had no ocular complaints except for refractive errors, and who had undergone LASIK, were enrolled in this study. We measured the concentrations of chondroitin 4 sulfate (C4S), chondroitin 6 sulfate (C6S), and MMP-9 activity with an enzyme-linked immunosorbent assay and an enzyme immunocapture activity assay preoperatively and postoperatively on days 1 and 4, week 1, and at 1 and 3 months. Results: Although the preoperative MMP-9 activity and the C4S concentration were highly correlated (r = 0.900; P < 0.001), they were not postoperatively correlated at month 1. Although the preoperative MMP-9 activity and the C6S concentration were highly correlated (r = 0.885; P < 0.001), they were not postoperatively correlated at either week 1 or months 1 and 3. Conclusions: The correlation appeared to be collapsed by LASIK, and it did not recover to the preoperative score at 3 months post-surgery. Our study indicates that the corneal wound healing was not terminated at 3 months following LASIK.

Four cases of traumatic hypotony maculopathy treated by various methods.

Several reports have been published on methods for treating hypotony maculopathy. Currently, the preferred choice of treatment depends on the severity of the illness. We experienced four cases of traumatic hypotony maculopathy and treated them by various methods. Cases 1–3 were treated by various surgical treatments. Case 1 was treated by combined cataract surgery and pars plana vitrectomy. The vitreous cavity was replaced with 20% sulfur hexafluoride (SF6). Case 2 did not improve with laser trabeculoplasty, so further encircling was performed. Case 3 did not improve with photocoagulation of the ciliary body and injection of 20% SF6 into the vitreous cavity. Consequently, this case required suturing of the ciliary body to the sclera, cryopexy for the ciliary body, and injection of 100% SF6. Case 4 was treated only with eye drops. Intraocular pressure (IOP) increased in all cases as a result of treatment. Treatment improved hypotony maculopathy in all cases. Pre-treatment visual acuities ranged from 0.03 to 0.4, with IOP ranging from 2 to 10 mmHg. Post-treatment visual acuity ranged from 0.09 to 1.2, with IOP ranging from 14 to 16 mmHg. Only case 2 resulted in poor visual prognosis because of choroidal rupture near the foveola. The difficulty in choosing treatment methods lies in the need for multiple surgical treatments for some cases. Effective and noninvasive treatment methods are expected to be established in the future.

A case of iridoschisis associated with lens displacement into the vitreous cavity

We report the case of a 67-year-old woman with a lens that was displaced into the vitreous cavity in one eye and ipsilateral iridoschisis. She was free from a history of ocular trauma or of heritable ocular disease. Her best-corrected visual acuity was 1.2 bilaterally and right eye showed signs of iridoschisis. The corneal endothelial cell density decreased to 1,263 cells/mm2 in the right eye preoperatively. We speculated that iris tissue flowing in the anterior chamber might have intermittently touched the corneal endothelium. 25-gauge pars plana vitrectomy and lens removal were performed immediately. Free-floating iris tissue was cut during surgery with care not to injure the corneal endothelial cells. The postoperative progress was satisfactory and scleral fixation of an intraocular lens is planned. Iridoschisis is an uncommon cause of lens displacement into the vitreous cavity.

Photorefractive keratectomy: measuring the matrix metalloproteinase activity and chondroitin sulfate concentration in tear fluid

We herein report the case of a 20-year-old man who underwent a photorefractive keratectomy (PRK). We measured matrix metalloproteinase-9 (MMP-9) activity and chondroitin 4 sulfate and chondroitin 6 sulfate concentrations in tear fluid. Tear fluid was collected pre-operatively via microcapillary tube, and was collected postoperatively on the first and fourth days, and after one week, one month, three months, and six months. Samples were formulated by dilution with 200 μL of saline. MMP-9 activity was analyzed by an enzyme immunocapture activity assay, and the concentrations of chondroitin sulfate were analyzed by enzyme-linked immunosorbent assay. No complications were observed after surgery, except for a minimal subepithelial haze. Although MMP-9 activity changed on the fourth postoperative day, the activity changed only minimally at this time. Chondroitin 4 sulfate concentrations in tear fluid increased dramatically from one week to one month, decreased transiently at three months, and increased by six months. The chondroitin 6 sulfate concentration did not normalize within one week, and decreased from one week to three months compared with the preoperative score, and was close to the preoperative score at six months. We conclude that corneal wound healing was still incomplete six months after PRK, and chondroitin 4 sulfate appears to be critical in this process.

Lens dislocation has a possible relationship with laser iridotomy

We report our recent experience of four eyes with spontaneous lens dislocation in four patients with no history of trauma or any systemic disease associated with zonular dialysis. Lens dislocation developed with 0.5 to 6 months following laser iridotomy. All patients were male and two eyes were complicated with acute primary angle closure glaucoma preoperatively. Case 1 showed bilateral lens dislocation, while cases 2 and 3 involved unilateral lens dislocation. Cases 2 and 3 showed lenses completely dislocated into the vitreous cavity. All cases needed lens removal and scleral fixation of intraocular lenses. Final visual acuity was 1.2 in all cases. We suspect that laser iridotomy may induce localized zonular dialysis that results in progressive zonular weakness, leading to lens dislocation.