Measurement of intraocular pressure using the NT-4000: a new non-contact tonometer equipped with pulse synchronous measurement function.

PURPOSE: NT-4000 (Nidek Co. Ltd., Gamagori, Japan) is a new non-contact tonometer (NCT) equipped with pulse synchronous measurement function that can measure intraocular pressure (IOP) synchronized with the ocular pulse. The purpose of this study was to evaluate the usefulness of NT-4000 in normal subjects and in patients with glaucoma and ocular hypertension. METHODS: This study included 175 eyes of 175 subjects. Firstly, the IOP was measured using NT-4000 without the pulse synchronous measurement function (NTn). Secondly, the IOP at peak, middle, and trough phases of the pulse signal were measured using NT-4000 with the pulse synchronous measurement function (NTp, NTm, NTt, respectively). Additionally, the IOP was measured with Goldmann applanation tonometer (GT). The coefficient of variation (CV) of three readings in the NCT measurements was used to evaluate the intra-session reproducibility. Statistical comparisons were performed using Wilcoxon signed rank test and one-way analysis of variance with Scheffe's test. Linear regression analysis was used to calculate correlation coefficients. P values less than 0.05 were accepted as statistically significant. RESULTS: The CV of NTn, NTp, NTm, and NTt were 6.4%, 5.5%, 4.9%, and 5.2%, respectively. The CV of NTp, NTm, and NTt were significantly smaller than that of NTn (P = 0.007, P < 0.001, P < 0.001, respectively). NTp was significantly higher than NTt (P = 0.038). GT was significantly correlated with NTn, NTp, NTm, and NTt (r = 0.898, P < 0.001; r = 0.912, P < 0.001; r = 0.908, P < 0.001; r = 0.900, P < 0.001, respectively). CONCLUSION: NT-4000 can detect the fluctuation of IOP associated with the ocular pulse.

Severe hypotony after macular translocation surgery with 360-degree retinotomy.

PURPOSE: To report a case of severe hypotony after macular translocation with 360-degree retinotomy. DESIGN: Interventional case report. METHODS: A 50-year-old woman with myopic neovascular maculopathy underwent macular translocation with 360-degree retinotomy in her left eye. RESULTS: After the second procedure of silicone oil removal, severe hypotony developed. No clear sign of leakage was found. Pure perfluoropropane gas tamponade was then performed, which resulted in temporal resolution of severe hypotony, but the hypotony recurred as the gas bubble was absorbed. Ten weeks after the second surgery, the hypotonous eye was refilled with silicone oil. No apparent cyclitic membrane was observed intraoperatively. After this procedure, the choroidal and retinal folds regressed; intraocular pressure has been between 5 and 7 mm Hg for more than 4 months thereafter. CONCLUSION: Severe hypotony can occur as a complication of otherwise uneventful macular translocation with 360-degree retinotomy.

Surgical management of retinal detachment associated with myopic macular hole: anatomic and functional status of the macula.

PURPOSE: To evaluate the postoperative status of the macula after vitreous surgery with internal limiting membrane removal for macular hole related retinal detachment in patients with severe myopia. DESIGN: Interventional case series. METHODS: We prospectively examined 10 eyes with retinal detachment associated with a myopic macular hole from 10 consecutive patients, and performed pars plana vitrectomy with internal limiting membrane peeling. Macular buckling was performed in one eye during the initial treatment and in three eyes during subsequent operations. The main outcome measures were the anatomic reattachment rate and the postoperative status of the macular hole. We examined the macular area pre- and postoperatively with slit-lamp biomicroscopy and with a scanning laser ophthalmoscope. Cross-sectional imaging of the macular area was conducted with optical coherence tomography. RESULTS: Successful retinal reattachment was achieved in seven eyes (70%) after the initial surgery and in three eyes (30%) after additional procedures. Visual acuity remained unchanged in two eyes (20%), and improved by two or more logarithmic units of minimum angle of resolution (logMAR) measurement in eight eyes (80%). The macular hole was anatomically closed in only one eye (10%). Postoperative enlargement of the macular hole was observed in seven eyes. CONCLUSIONS: In highly myopic eyes with macular hole related retinal detachment, closure of the macular hole is difficult to attain despite the complete relief of tangential traction by internal limiting membrane peeling. Results indicate the presence of a possible imbalance between the retina and the choroid-sclera complex associated with axial elongation and posterior staphyloma in highly myopic eyes.

Relationship between indices of Humphrey perimetry and Frequency Doubling Technology Perimetry in glaucoma.

PURPOSE: To study whether the correlation between indices of Humphrey perimetry and Frequency Doubling Technology (FDT) perimetry differs in the early and later stages of glaucoma. METHODS: This study included 200 eyes of 200 patients with primary open-angle glaucoma or normal-tension glaucoma. The eyes were classified into the early and later stages by the median value (-4.51 dB) (Classification 1; n = 100 and 100, respectively) or the average value of the maximum and minimum values (-11.90 dB) (Classification 2; n = 165 and 35, respectively) of mean deviation (MD) obtained from a set of measurements with the Humphrey Full-Threshold 30-2 program in all eyes. The correlation between MD (H-MD) or pattern standard deviation (PSD) (H-PSD), as obtained from another set of measurements with the Humphrey Full-Threshold 30-2 program, and MD (F-MD) or PSD (F-PSD), as calculated by the Full-Threshold N-30 program of FDT perimetry, were evaluated using linear regression analysis. RESULTS: Overall, H-MD and H-PSD significantly correlated with F-MD (r = 0.713; P < 0.001) and F-PSD (r = 0.731; P < 0.001), respectively. In each of Classifications 1 and 2, H-MD and H-PSD significantly correlated with F-MD and F-PSD, respectively, both in the early and later stages. However, in each classification, the correlation between H-MD and F-MD differed significantly between the two stages (Classification 1; P < 0.001; Classification 2, P = 0.003), while the correlation between H-PSD and F-PSD did not differ significantly between the two stages. CONCLUSION: The degree of correlation between H-MD and F-MD differed between the early and later stages of glaucoma.

Optic disc topography as measured by confocal scanning laser ophthalmoscopy and visual field loss in Japanese patients with primary open-angle or normal-tension glaucoma.

PURPOSE: To determine whether differences in the optic disc topography and those in the relation between the optic disc topography and visual field indices exist between Japanese patients with primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG). METHODS: The study included consecutive Japanese patients with POAG (n = 60) or NTG (n = 60). Using the Heidelberg Retina Tomograph (HRT), we measured disc area, cup area, cup-to-disc area ratio, rim area, cup volume, rim volume, cup shape measure, and height variation contour. Each HRT parameter was measured in the total optic disc and in its four 90 degree quadrants (superior, temporal, inferior, and nasal). The mean deviation for the entire field and the sum of the total deviation values corresponding to each optic disc quadrant were calculated using the Humphrey full-threshold 30-2 program. RESULTS: No significant differences were found between the POAG and NTG groups for any HRT parameter either globally or regionally. There were no significant differences between the two groups in the correlation coefficients between any HRT parameter and the corresponding visual field indices either globally or regionally. CONCLUSION: No significant differences were apparent between Japanese patients with POAG and NTG both in the optic disc parameters as measured by HRT and in the degree of correlation between HRT parameter and the corresponding visual field indices.

Relationship between optic nerve head microcirculation and visual field loss in glaucoma.

PURPOSE: To study the relationship between optic nerve head blood flow velocity and visual field loss in patients with primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG). METHODS: This study included 44 eyes of 44 patients with POAG and 44 eyes of 44 patients with NTG. To evaluate optic nerve head blood flow velocity, the square blur rate (SBR) was measured by means of laser speckle flowgraphy. The correlation between SBR and Humphrey visual field indices was evaluated with linear regression analysis. RESULTS: In the NTG group, the average SBR at the superior and inferior temporal neuroretinal rim was positively correlated with mean deviation (MD) (r = 0.349, p = 0.020). The SBR at the superior or inferior temporal neuroretinal rim was positively correlated with the sum of the total deviations in the corresponding hemifields (r = 0.299, p = 0.049; r = 0.354, p = 0.019, respectively). The correlations between SBR and MD did not differ statistically between the NTG and POAG groups; however, no significant correlation between SBR and visual field indices was observed in the POAG group. CONCLUSION: These results suggested that the change in the circulation of the optic nerve head may be related to visual field damage in the NTG group but may be less involved in visual field damage in the POAG group.

Chondromodulin-I expression in rat articular cartilage.

The localization and expression of chondromodulin-I (ChM-I), an angiogenesis inhibitor, in the rat articular cartilage during maturation from 2 to 10 weeks of age were examined by immunohistochemistry, Western blot analysis and ribonuclease protection assay, and the results were compared with those in the epiphyseal cartilage. ChM-I was found to be diffusely immunostained in the inter-territorial space of the cartilage matrix from the intermediate to the deep layers at the immature stage. As the articular cartilage matured, the immunoreactivity was localized around the hypertrophic chondrocytes in the deep layer and the immunoreactivity became weak after maturation. In contrast, the ChM-I immunoreactivity was intense in the epiphyseal cartilage at all ages examined. ChM-I was detected by Western blotting as a broad band or occasionally as a cluster of multiple bands (approximately 25 kDa) in both the articular and the epiphyseal cartilage. The intensity of the bands decreased gradually with age in the articular cartilage, but was unchanged in the epiphyseal cartilage at all ages. Ribonuclease protection assay revealed that ChM-I mRNA also decreased gradually with age in the articular cartilage in parallel with the maturation of the articular cartilage, while no decrease in ChM-I mRNA was found in the epiphyseal cartilage. The expression of ChM-I mRNA in the articular cartilage was less than that in the epiphyseal cartilage at all ages. The decrease in amount of ChM-I in the mature articular cartilage suggests that ChM-I plays a more important role in the maintenance of avascularity in the immature articular cartilage than in the mature one. The avascular condition may be preserved by angiogenic inhibitors or mechanisms other than ChM-I in the mature articular cartilage.

Localization and expression of chondromodulin-I in the rat cornea.

The localization and expression in the rat cornea of chondromodulin-I (ChM-I), an inhibitory angiogenesis factor, were examined by immunohistochemistry, Western blot analysis, ribonuclease protection assay, and real-time PCR assay. We found immunoreactivity for ChM-I in the epithelial layer but not the stromal layer or endothelial layer in the cornea, in addition to the positive ChM-I immunoreactivity in other sites in the eye such as the sclera, retina, and ciliary body. The ChM-I immunoreactivity was most intense at the outside of the basal cells and in their cytoplasm while the intensity of the immunoreactivity decreased gradually from the wing cells to the superficial cells in the corneal epithelial layer. No reactivity however, was detected in the Bowman's membrane or conjunctival epithelial cells which had continuity with the corneal epithelial cells. The expression of ChM-I mRNA was demonstrated in the cornea at one-third less intensity than that in the sclera with choroids and retinal pigment epithelium by ribonuclease protection assay and real-time PCR. ChM-I in the corneal epithelial layer may prevent neovascularization and maintain avascularity in the cornea.

Expression of the cartilage derived anti-angiogenic factor chondromodulin-I decreases in the early stage of experimental osteoarthritis.

OBJECTIVE: Chondromodulin-I (ChM-I), a cartilage derived anti-angiogenic factor, has been shown to regulate the vascular invasion during endochondral bone formation. We evaluated the expression and localization of ChM-I in articular cartilage during the progression of osteoarthritis (OA) in the rat, and correlated ChM-I expression with the increase in vascular invasion into OA articular cartilage. METHODS: Expression of ChM-I, type II collagen, basic fibroblast growth factor, vascular endothelial growth factor (VEGF), and matrix metalloproteinases MMP-9 and MMP-13 were examined in articular cartilage of intact growing and adult rats and in the surgically induced OA model using in situ hybridization, Western blot analysis, and immunohistochemistry. Co-immunostaining for ChM-I and CD-31 was performed to localize ChM-I and neovascularization in articular cartilage at advanced stage of OA. RESULTS: Abundant expression of ChM-I protein was detected in avascular regions of the developing and adult healthy articular cartilage. In early OA, ChM-I expression decreased in the superficial zone of articular cartilage, while levels of proteoglycan and type II collagen were comparable to control. In advanced OA, ChM-I expression was reduced in all zones of articular cartilage, and the number of VEGF-expressing cells was increased. Immunohistochemical studies showed that vascular invasion occurred in proximity to chondrocytes with high expression of pro-angiogenic markers, and decreased expression of ChM-I. CONCLUSION: High expression of ChM-I was detected in articular cartilage of growing and normal adult joints, implicating its role in the maintenance of avascularity of intact articular cartilage. Expression of ChM-I decreased, while expression of VEGF and other pro-angiogenic factors increased, in OA cartilage. These findings suggest the loss of ChM-I from articular cartilage might be responsible in part for promoting blood vessel invasion into the cartilage during progression of OA.

Localization of olfactomedin-related glycoprotein isoform (BMZ) in the golgi apparatus of glomerular podocytes in rat kidneys.

Agene encoding olfactomedin-related glycoprotein was isolated from rat glomerulus despite its prior identification as a neuron-specific gene. The mRNA expression was remarkably intense in renal glomerulus and brain and faint in the lung and eye among rat systemic organs. Although the brain contained four mRNA variants (AMY, AMZ, BMY, and BMZ) transcribed from a single gene, the glomerulus, lung, and eye expressed only two variants (BMZ and BMY). The glycoprotein was intensely immunolocalized in glomerular podocytes and neurons by using an antibody against synthetic peptide of the M region, but weak in endothelial cells of the kidney and lung. Bronchiolar epithelial cells in the lung, and ciliary, corneal, and iris epithelial cells in the eye were also stained. Immunogold electron microscopy revealed selective localization of olfactomedin-related glycoprotein at the Golgi apparatus in podocytes. In glomerular culture, the staining was also intense at a juxtanuclear region in synaptopodin-positive epithelial cells of irregular shape (phenotypic feature of podocytes), whereas it was weak in synaptopodin-negative ones of cobblestone-like appearance (phenotypic feature of parietal epithelial cells of Bowman's capsule). Interestingly, Western blot analysis identified an intense band corresponding to BMZ isoform and another faint band corresponding to BMY isoform in the glomerulus, whereas the intensity of these two bands were nearly equal in the lung and eye. In the brain, four bands corresponding to four isoforms were observed apparently. Computer sequence analysis predicted coiled-coil structures in the secondary structure of the glycoprotein similar to those in Golgi autoantigens, suggesting significant roles in the unique functions of the Golgi apparatus in rat podocytes and neurons.