Hidetoshi Tsukamoto

Intravitreal levels of vascular endothelial growth factor and interleukin-6 are correlated with macular edema in branch retinal vein occlusion

BackgroundTo investigate whether vascular endothelial growth factor (VEGF) or interleukin-6 (IL-6) contributes to the pathogenesis of macular edema in eyes with branch retinal vein occlusion (BRVO), the correlations between these factors were investigated.MethodsWe studied 25 patients suffering from macular edema with BRVO and 14 patients with nonischemic ocular disease (control group). The degree of retinal ischemia was evaluated in terms of the area of capillary nonperfusion using Scion Images, and the severity of macular edema was examined using optical coherence tomography. Vitreous fluid samples were obtained at the time of vitreoretinal surgery, and VEGF and IL-6 levels in the vitreous fluid and plasma were determined by means of enzyme-linked immunosorbent assays.ResultsVitreous fluid levels of VEGF and IL-6 were significantly elevated in patients with BRVO compared with control patients (P=0.0011 and P<0.0001, respectively). Also, the vitreous level of VEGF was significantly correlated with that of IL-6 (P=0.0012), and vitreous levels of VEGF and IL-6 were correlated with the size of the BRVO nonperfusion area (P<0.0001 and P=0.0033, respectively). Furthermore, vitreous levels of VEGF and IL-6 were correlated with the severity of macular edema (P=0.0008 and P=0.0191, respectively) and the severity of macular edema of BRVO was significantly correlated with the size of the BRVO nonperfusion area (P=0.0044).ConclusionsThe levels of VEGF and IL-6 are increased in patients with macular edema with BRVO and are significantly correlated with the size of the nonperfusion area and the severity of macular edema. Therefore, they may play a role in macular edema with BRVO.

Myopia and advanced-stage open-angle glaucoma

OBJECTIVE To investigate the effect of myopic refraction on the central visual field in patients with advanced open-angle glaucoma (OAG). DESIGN Multicenter cross-sectional study. PARTICIPANTS Three hundred thirteen OAG eyes (176 eyes of 176 primary open-angle glaucoma [POAG] patients and 137 eyes of 137 normal-tension glaucoma [NTG] patients) with clear ocular media and a mean deviation (MD) <-15 dB. Patients with a recorded maximum intraocular pressure (IOP) of 22 mmHg or greater were classified as POAG, and those with an IOP of 21 mmHg or less were classified as NTG. METHODS Multiple regression analysis was used to study the influence of refraction on 12 central test points of the C30-2 Humphrey program, and the differences in visual field defects between POAG and NTG eyes were examined using logistic discriminant analysis. In the multiple regression analysis, total deviation (TD) of the 12 test points was graded and used as the dependent variable, and MD and the spherical equivalent refraction were the explanatory variables. In the logistic discrimination analysis, TD, MD, and refraction were covariants that determined the OAG subtypes. MAIN OUTCOME MEASURES TD values of the 12 central test points (C30-2 program). RESULTS Higher myopic refraction was significantly associated with more damage at a point just temporal and inferior to the fixation point in POAG eyes, whereas it was significantly associated with less damage at test points just temporal and superior to the fixation point in NTG eyes. After correcting for the influence of refraction, POAG eyes had significantly more damage at a test point just temporal and inferior to the fixation point, whereas NTG eyes had significantly more damage at those test points nasal and inferior to the fixation point. CONCLUSIONS High myopia constitutes a threat to the remaining lower cecocentral visual field and is one of the factors that interfere with the quality of vision in advanced OAG with high IOP but not low IOP.

Contact-Based Stiffness Sensing of Human Eye

Goldmann applanation tonometry is commonly used for measuring intraocular pressure (IOP) to diagnose glaucoma. However, the measured IOP by conventional applanation tonometry is valid only under the assumption that all subjects have the same structural eye stiffness. This paper challenges in vivo measurement of eye stiffness with a noninvasive approach and investigates individual differences of eye stiffness. Eye stiffness is defined by the applied force and displacement of the cornea. The displacement is detected based on captured images by a high resolution camera. The experimental results show that the measured stiffness nicely matches the analytical result that is derived from a simple spherical deformation model with an internal pressure. However, some subjects have different eye stiffness even with the same IOP. IOP with abnormal stiffness may be over/underestimated by conventional applanation tonometry. The proposed eye stiffness measurement can help detect the misestimated eye and it contributes to the early detection of glaucoma.

A comparative clinical study of latanoprost and isopropyl unoprostone in Japanese patients with primary open-angle glaucoma and ocular hypertension

PurposeTo compare the efficacy and safety of latanoprost versus isopropyl unoprostone (unoprostone) in Japanese patients with primary open-angle glaucoma (POAG) or ocular hypertension (OH). MethodsAn 8-week, multicenter, randomized, comparative study was performed in 48 Japanese patients with POAG or OH. Four patients (two in each group) withdrew from the study, but their data were included in the safety assessment but not in the intraocular pressure (IOP) evaluation. The patients were randomly treated with latanoprost 0.005% once daily or unoprostone 0.12% twice daily for 8 weeks. IOP was measured at baseline and 2, 4, and 8 weeks after treatment. In addition, ocular and systemic adverse events were recorded. ResultsThe baseline IOPs were similar between the latanoprost (n = 25) and unoprostone (n = 19) groups (24.3 ± 2.4 mm Hg vs 23.3 ± 2.1 mm Hg, respectively, P = 0.18). The IOP reductions from baseline at 2, 4, and 8 weeks after treatment were 5.8 ± 2.4, 6.6 ± 2.5, and 6.7 ± 2.0 mm Hg in the latanoprost group, and 3.8 ± 2.0, 3.5 ± 2.3, and 3.3 ± 3.0 mm Hg in the unoprostone group, respectively. The IOP reduction in the latanoprost group at 8 weeks was larger than that in the unoprostone group (P < 0.001, analysis of covariance). Five adverse events were observed in 4 (15%) of 27 patients in the latanoprost group, and five adverse events were observed in 4 (20%) of 21 patients in the unoprostone group. There was no difference in the incidence of adverse events between groups (P = 0.71). ConclusionLatanoprost produced a statistically greater reduction in IOP than unoprostone in Japanese patients with POAG or OH.

Mathematical and optimal clustering of test points of the central 30-degree visual field of glaucoma.

PurposeTo determine a mathematically optimal sector pattern of the central 30° visual field for the follow-up of glaucomatous visual field change based on a large number of actual visual field test data of patients with glaucoma. MethodsVisual field test data obtained from 1,039 eyes of 1,039 patients with open-angle glaucoma (OAG) using the 30-2 program of the Humphrey Field Analyzer were used for sectorization of the central 30° visual field. Of the 1,039 visual field data, 698 (modeling data) were used for determining the sector pattern and 341 (testing data) for checking the sector pattern. The modeling data were further divided into three groups according to the mean deviation (MD) (MD ≥ −10 dB, −20 ≤ MD < −10 dB, and MD < −20 dB), and the sector pattern was constructed from visual field data of each group using a clustering procedure called VARCLUS. The testing data were used for determining the optimal sector pattern. In a separate set of repeated visual field data of 303 patients with OAG, the fluctuation of MD, sector values of each sector determined, and total deviation of each test point were calculated and compared. ResultsThe sector pattern constructed from visual field data of MD ≥ −10 dB summarized the visual field performance most effectively. The fluctuation of the sector value of each sector was roughly 1.5 times smaller than the total deviation of each test point. ConclusionThe sector pattern determined may be useful in analyses of the visual field data of patients with glaucoma.

Understanding eye deformation in non-contact tonometry

Non-contact tonometers are widely used to measure the internal eye pressure, i.e. the IntraOcular Pressure (IOP), which is an important parameter for the diagnosis and treatment of glaucoma. During the measurement, the eye is deformed by a short air pulse. Commonly the pressure dependent deformation is estimated from the time when the eye becomes flat, which is derived from the monitored reflection of an incident infrared light. We used a high speed camera to capture the complete motion of the eye directly and obtain more data during the pressure measurement. Assuming a simple eye model with non-linear material properties of the cornea, we extend our previous analysis of the motion of the eye, and obtain a similar principle shape of the eye deformation as observed in the experiments

Dynamic sensing of human eye using a high speed camera

The eye pressure is an important index for judging whether an eye suffers from glaucoma or not. Conventional eye pressure measurements provide us with meaningful data only under the assumption that all the subjects have the same eye stiffness. Our former work, however, says that the assumption is not valid. This work is an extended version. By combining both a high speed camera with 5000[fps] and an air puff supply system, the eye surface can be precisely tracked with respect to time. We introduce a new parameter, which is the displacement at a predetermined applied force. We found that the parameter can strongly emphasize the characteristic of the individual eye stiffness and keeps a high correlation with the measured external eye pressure, so called IOP (intraocular pressure).

Measurement and Analysis of Human Eye Excited by an Air Pulse

For the diagnosis and treatment of glaucoma, a reliable and non-invasive measurement method of the internal eye pressure, i.e. the intraocular pressure (IOP), is desired. The IOP resists a deformation of the eye and thus non-contact tonometers, which deform the eye by a short air pulse, are suitable to estimate the IOP. By monitoring the reflection of an incident infrared light, the tonometer measures the time an applied air jet flattens part of the eye. The relationship between flattening time and IOP are provided by calibration. In our work, we used an additional high speed camera to capture the eye deformation directly and obtain more data during the pressure measurement. We show that the principle shape of the deformation can be understood by assuming simple non-linear material properties of the cornea in an eye model. Furthermore, we discuss which sources of error are still needed to be overcome to give a medical meaningful diagnosis for the examined eye by the data from the high speed camera

Prevalence of glaucoma in adults with Down's syndrome.

PurposeTo compare the prevalence of glaucoma in adults with Downs syndrome (DS) to that in non-DS control adults.MethodsTwenty-six patients (14 men and 12 women) with DS and 188 control subjects (105 men and 83 women) were studied. The mean age was 35.1 ± 6.9 (± SD) years in the DS group and 36.9 ± 5.2 years in the control group. There were no significant differences in age or sex distribution between the two groups. Glaucoma was diagnosed by two glaucoma specialists based on the optic disc findings obtained through dilated pupils.ResultsThe prevalence of patients with glaucoma in the DS group was 11.5%, significantly higher (P = 0.014) than that in the control group, 1.1%. There was no significant difference in intraocular pressure between glaucomatous eyes (12.2 ± 3.2 mmHg) and nonglaucomatous eyes (11.1 ± 4.1 mmHg) in the DS group (P = 0.465).ConclusionsThe prevalence of glaucoma in adult patients with DS was significantly higher than that in age-matched control subjects. Jpn J Ophthalmol 2006;50:274–276

Dynamic Properties of Human Eyes

This paper presents novel details on the dynamic behavior of human eyes. A high speed camera is used to capture the movement of the eye surface, which is excited by an air jet. For one group of subjects the dynamic response of the eyes ends shortly after the air jet stops. For another group of subjects a distinct offset in the displacement remains, which takes a significantly longer time to vanish. The two distinct phases in the eye movement are the result of the dynamic response of the cornea and the total eye, respectively. A deeper understanding of the eye dynamics is important for obtaining a higher reliability of diagnostic tools for glaucoma