Objective: In previous decades, glaucoma has been primarily attributed to elevated intraocular pressure (IOP), but this has gradually been replaced by the development of optic neuropathy as the central concept of glaucoma in developed countries. However, there still remain strong controversies in the definition of glaucoma in China. In this current review, we are going to discuss these controversies and elaborate on the historical transitions of the definition of glaucoma both in China and developed countries. Furthermore, we will briefly describe the "ocular-cranial pressure gradient" theory and discuss the relationship between glaucoma and degenerative diseases of the central nervous system (CNS) in order to show the complex pathogenesis of glaucoma and the importance for the modification to the definition of glaucoma. Data Sources: We performed a comprehensive search in both PubMed and SinoMed using the following keywords: (a) "primary glaucoma" and "guideline," (b) "ocular-cranial pressure gradient," and (c) "glaucoma," "Alzheimer's disease," and "Parkinson's disease." The literature search included the related articles with no restrictions on publication date. Study Selection: The primary references were Chinese and English articles including (a) original guidelines and expert consensuses of primary glaucoma, (b) reviews focusing on the differences between various versions of these guidelines and consensuses, and (c) papers about ocular-cranial pressure gradient theory and the relationship between glaucoma and CNS degenerative diseases. Results: The definitions and classifications of both primary open-angle glaucoma and primary angle-closure glaucoma differ between Chinese glaucoma consensuses and international primary glaucoma guidelines. Chinese definitions and classifications put more emphasis on the IOP, while international guidelines put more emphasis on the presence of optic neuropathy. The ocular-cranial pressure gradient theory and the research on the relationship between glaucoma and CNS degenerative diseases have provided new directions for exploring the pathogenesis of glaucoma. Conclusions As regards the definition and classification of primary glaucoma, we find that there are still some discrepancies between Chinese expert consensuses and international guidelines. Glaucoma is a disease with complex etiologies, while its common characteristic is a specific optic neuropathy. The current definition and understanding of glaucoma is an ongoing and evolving process, reflecting our latest available evidence on its pathogenesis. Chinese ophthalmology community may need to update our guidelines, accommodating these latest developments.
China ; Glaucoma ; diagnosis ; physiopathology ; Glaucoma, Angle-Closure ; diagnosis ; physiopathology ; Glaucoma, Open-Angle ; diagnosis ; physiopathology ; Humans ; Intraocular Pressure ; physiology ; Ophthalmology ; methods

BACKGROUNDHigh intraocular pressure (IOP) and low central corneal thickness (CCT) are important validated risk factors for glaucoma, and some studies also have suggested that eyes with more deformable corneas may be in higher risk of the development and worsening of glaucoma. In the present study, we aimed to evaluate the association between corneal biomechanical parameters and asymmetric visual field (VF) damage using a Corvis-ST device in patients with untreated normal tension glaucoma (NTG).

METHODSIn this observational, cross-sectional study, 44 newly diagnosed NTG patients were enrolled. Of these, 31 had asymmetric VF damage, which was defined as a 5-point difference between the eyes according to the Advanced Glaucoma Intervention Study scoring system. Corneal biomechanical parameters were obtained using a Corvis-ST device, such as time from start until the first and second applanation is reached (time A1 and time A2, respectively), cord length of the first and second applanation (length A1 and length A2, respectively), corneal speed during the first and second applanation (velocity A1 and velocity A2, respectively), time from start until highest concavity is reached (time HC), maximum amplitude at the apex of highest concavity (def ampl HC), distance between the two peaks at highest concavity (peak dist HC), and central concave curvature at its highest concavity (radius HC).

RESULTSTime A1 (7.19 ± 0.28 vs. 7.37 ± 0.41 ms, P = 0.010), length A1 (1.73 [1.70-1.76] vs. 1.78 [1.76-1.79] mm, P = 0.007), length A2 (1.58 [1.46-1.70] vs. 1.84 [1.76-1.92] mm, P< 0.001), peak dist HC (3.53 [3.08-4.00] vs. 4.33 [3.92-4.74] mm, P = 0.010), and radius HC (6.20 ± 0.69 vs. 6.59 ± 1.18 mm, P = 0.032) were significantly lower in the worse eyes than in the better eyes, whereas velocity A1 and def ampl HC were significantly higher (0.156 [0.149-0.163] vs. 0.145 [0.138-0.152] m/s, P = 0.002 and 1.19 ± 0.13 vs. 1.15 ± 0.13 mm, P = 0.005, respectively). There was no significant difference in time A2, velocity A2, and time HC between the two groups. In addition, no difference was observed in IOP, CCT, and axial length. In the univariate and multivariate analyses, some of the Corvis-ST parameters, including time A1 and def ampl HC, were correlated with known risk factors for glaucoma, and there was also a significant positive correlation between def ampl HC and age.

CONCLUSIONSThere were differences in dynamic corneal response parameters but not IOP or CCT between the paired eyes of NTG patients with asymmetric VF damage. We suggest that the shape of the cornea is more easily altered in the worse eyes of asymmetric NTG patients.

Aged ; Biomechanical Phenomena ; physiology ; Cornea ; metabolism ; physiology ; Cross-Sectional Studies ; Female ; Glaucoma ; metabolism ; physiopathology ; Humans ; Intraocular Pressure ; physiology ; Low Tension Glaucoma ; metabolism ; physiopathology ; Male ; Middle Aged ; Multivariate Analysis ; Prospective Studies ; Visual Fields ; physiology

PURPOSE: To evaluate the effects of posterior subtenon triamcinolone acetonide injection on refractory diabetic macular edema (DME) after intravitreal bevacizumab (IVB) injection failure. METHODS: Patients with DME and central subfield thickness (CST) >300 microm who did not respond to IVB injections were retrospectively included. Specifically, we enrolled patients who were diagnosed with refractory DME and who experienced an increase in CST after 1 to 2 IVB injections or no decrease after > or =3 consecutive IVB injections. One clinician injected 20 mg of triamcinolone acetonide into the posterior subtenon space. All patients received ophthalmic examinations at baseline and at 2, 4, and 6 months post-baseline. Examinations included Snellen visual acuity, intraocular pressure, and spectral-domain optical coherence tomography. RESULTS: Forty eyes of 34 patients were included. The average baseline CST was 476 microm. The average CST decreased to 368 microm at 2 months, 374 microm at 4 months, and 427 microm at 6 months (p < 0.001 for all results, Wilcoxon signed-rank test). The average intraocular pressure increased from 15.50 to 16.92 mmHg at 2 months but decreased to 16.30 mmHg at 4 months and 15.65 mmHg at 6 months. Logarithm of the minimum angle of resolution visual acuity improved from 0.56 to 0.50 at 2 months (p = 0.023), 0.50 at 4 months (p = 0.083), and 0.48 at 6 months (p = 0.133, Wilcoxon signed-rank test). No complications were detected. CONCLUSIONS: Posterior subtenon triamcinolone acetonide is an effective and safe treatment for reducing CST in DME refractory to IVB.
Aged ; Angiogenesis Inhibitors/*therapeutic use ; Bevacizumab/*therapeutic use ; Diabetic Retinopathy/diagnostic imaging/*drug therapy/physiopathology ; Female ; Glucocorticoids/*administration & dosage ; Humans ; Injections, Intraocular ; Intraocular Pressure/physiology ; Intravitreal Injections ; Macular Edema/diagnostic imaging/*drug therapy/physiopathology ; Male ; Middle Aged ; Retrospective Studies ; Tenon Capsule/*drug effects ; Tomography, Optical Coherence ; Treatment Failure ; Triamcinolone Acetonide/*administration & dosage ; Vascular Endothelial Growth Factor A/antagonists & inhibitors ; Visual Acuity/physiology

No abstract available.
Aged ; Diagnosis, Differential ; Female ; Fluorescein Angiography ; Fundus Oculi ; Humans ; *Intraocular Pressure ; Regional Blood Flow/*physiology ; Retina/*diagnostic imaging ; Retinal Hemorrhage/*diagnosis/physiopathology ; Retinal Vein Occlusion/*diagnosis

PURPOSE: To evaluate the influence of biometric variables on refractive outcomes after cataract surgery in angle-closure glaucoma (ACG) patients. METHODS: In this case-control study, 42 ACG patients, 40 open-angle glaucoma (OAG) patients, and 35 controls without glaucoma who had undergone conventional cataract surgery were enrolled consecutively. Electronic medical records, including preoperative biometric variables (keratometric diopter, axial length, anterior chamber depth, and lens thickness), the refractive change (RC), and the absolute value of refractive change (ARC) were reviewed. RESULTS: In the control and OAG patients, the anterior chamber depth was negatively correlated with the ARC (r = -0.344, p = 0.043 and r = -0.431, p = 0.006, respectively), whereas there was no correlation in the ACG patients. Lens thickness was positively correlated with the RC, but not with the ARC, in the control and OAG groups (r = 0.391, p = 0.020 and r = 0.501, p = 0.001, respectively). In contrast, lens thickness in the ACG group was not correlated with the RC but was positively correlated with the ARC (r = 0.331, p = 0.032). CONCLUSIONS: In contrast with the anterior chamber depth, preoperatively measured lens thickness may be a useful predictor of the direction of the RC after cataract surgery in control and OAG patients. However, in ACG patients, a thicker lens was correlated with a larger RC, regardless of the direction of the shift (hyperopic or myopic).
Aged ; Anterior Chamber/*diagnostic imaging ; Biometry/*methods ; Female ; Follow-Up Studies ; Glaucoma, Angle-Closure/*complications/diagnosis/surgery ; Glaucoma, Open-Angle/*complications/diagnosis/surgery ; Humans ; *Intraocular Pressure ; Male ; Middle Aged ; *Phacoemulsification ; Refraction, Ocular/*physiology ; Retrospective Studies ; Tomography, Optical Coherence

PURPOSE: We explored the performance of and pressure elevation caused by small-diameter microtubes used to reduce overfiltration. METHODS: Using a syringe pump-driven constant-flow setting (2 µL/min), pressures were measured for polytetrafluoroethylene (PTFE) microtubes 5 mm in length with inner diameters of 51, 64, and 76 µm and for polyether block amide (PEBAX) microtubes with an inner diameter of 76 µm. Experiments (using microtubes only) were initially performed in air, water, and enucleated pig eyes and were repeated under the same conditions using intraluminal 9/0 nylon stents. RESULTS: The pressures measured in air in 51-, 64-, and 76-µm-diameter PTFE microtubes differed significantly (22.1, 16.9, and 12.2 mmHg, respectively; p < 0.001), and that of the 76-µm-diameter PEBAX microtube was 15.8 mmHg (p < 0.001 compared to the 12.2 mmHg of the 76-µm-diameter PTFE microtube). The pressures measured in water also differed significantly among the three microtubes at 3.9, 3.0, and 1.4 mmHg, respectively, while that in the PEBAX microtube was 2.6 mmHg (all p < 0.001). Using the intraluminal stent, the pressure in water of the three different PTFE microtubes increased to 22.6, 18.0, and 4.1 mmHg, respectively, and that in the PEBAX microtube increased to 10.5 mmHg (all p < 0.001). Similar trends were evident when measurements were performed in pig eyes. CONCLUSIONS: Although microtubes of smaller diameter experienced higher pressure in air, reduction of the inner diameter to 51 µm did not adequately increase the pressure attained in water or pig eyes. Insertion of an intraluminal stent effectively elevated the latter pressures. PEBAX microtubes created higher pressures than did PTFE microtubes.
Animals ; Disease Models, Animal ; Glaucoma/physiopathology/*surgery ; *Glaucoma Drainage Implants ; Intraocular Pressure/*physiology ; Ophthalmologic Surgical Procedures/*instrumentation ; *Polytetrafluoroethylene ; Prosthesis Design ; Swine

BACKGROUNDGlaucoma is a progressive optic neuropathy characterized by degeneration of neurons due to loss of retinal ganglion cells (RGCs). High intraocular pressure (HIOP), the main risk factor, causes the optic nerve damage. However, the precise mechanism of HIOP-induced RGC death is not yet completely understood. This study was conducted to determine apoptosis of RGC-5 cells induced by elevated hydrostatic pressures, explore whether laminin is associated with apoptosis under pressure, whether laminin can protect RGCs from apoptosis and affirm the mechanism that regulates the process of RGCs survival.

METHODSRGC-5 cells were exposed to 0, 20, 40, and 60 mmHg in a pressurized incubator for 6, 12, and 24 h, respectively. The effect of elevated hydrostatic pressure on RGC-5 cells was measured by Annexin V-fluorescein isothiocyanate/propidium iodide staining, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and Western blotting of cleaved caspase-3 protein. Location and expression of laminin were detected by immunofluorescence. The expression of β1-integrin, phosphorylation of focal adhesion kinase (FAK) and protein kinase B (PKB, or AKT) were investigated with real-time polymerase chain reaction and Western blotting analysis.

RESULTSElevated hydrostatic pressure induced apoptosis in cultured RGC-5 cells. Pressure with 40 mmHg for 24 h induced a maximum apoptosis. Laminin was declined in RGC-5 cells after exposing to 40 mmHg for 24 h. After pretreating with laminin, RGC-5 cells survived from elevated pressure. Furthermore, β1-integrin and phosphorylation of FAK and AKT were increased compared to 40 mmHg group.

CONCLUSIONSThe data show apoptosis tendency of RGC-5 cells with elevated hydrostatic pressure. Laminin can protect RGC-5 cells against high pressure via β1-integrin/FAK/AKT signaling pathway. These results suggest that the decreased laminin of RGC-5 cells might be responsible for apoptosis induced by elevated hydrostatic pressure, and laminin or activating β1-integrin/FAK/AKT pathway might be potential treatments to prevent RGC loss in glaucomatous optic neuropathy.

Apoptosis ; Cells, Cultured ; Focal Adhesion Protein-Tyrosine Kinases ; physiology ; Humans ; Hydrostatic Pressure ; Integrin beta1 ; physiology ; Intraocular Pressure ; Laminin ; physiology ; Proto-Oncogene Proteins c-akt ; physiology ; Retinal Ganglion Cells ; physiology ; Up-Regulation

PURPOSE: To compare the surgical results of trabeculectomy and Ahmed glaucoma valve implantation after a previous failed trabeculectomy. METHODS: A retrospective comparative case series review was performed on 31 eye surgeries in 20 patients with primary congenital glaucoma who underwent trabeculectomy or Ahmed glaucoma valve implantation after a previous failed trabeculectomy with mitomycin C. RESULTS: The preoperative mean intraocular pressure was 25.5 mmHg in the trabeculectomy group and 26.9 mmHg in the Ahmed glaucoma valve implantation group (p = 0.73). The 48-month postoperative mean intraocular pressure was 19.6 mmHg in the trabeculectomy group and 20.2 mmHg in the Ahmed glaucoma valve implantation group (p = 0.95). The 12-month trabeculectomy success rate was 69%, compared with 64% for Ahmed glaucoma valve implantation, and the 48-month success rates were 42% and 36% for trabeculectomy and valve implantation, respectively. The success rates following the entire follow-up period were not significantly different between the two groups (p > 0.05 by log rank test). Postoperative complications occurred in 25% of the trabeculectomy-operated eyes and 9% of the Ahmed-implanted eyes (p = 0.38). CONCLUSIONS: There was no significant difference in surgical outcome between the trabeculectomy and Ahmed glaucoma valve implantation groups, neither of which had favorable results. However, the trabeculectomy group demonstrated a higher prevalence of adverse complications such as post-operative endophthalmitis.
Child, Preschool ; Female ; Follow-Up Studies ; Glaucoma/congenital/physiopathology/*surgery ; *Glaucoma Drainage Implants ; Humans ; Infant ; Intraocular Pressure/*physiology ; Male ; Mitomycin/*adverse effects ; Nucleic Acid Synthesis Inhibitors/adverse effects ; Reoperation ; Retrospective Studies ; Time Factors ; Trabeculectomy/*adverse effects/*methods ; Treatment Failure ; Treatment Outcome ; *Visual Acuity

PURPOSE: To investigate the risk factors for initial central scotoma (ICS) compared with initial peripheral scotoma (IPS) in normal-tension glaucoma (NTG). METHODS: Fifty-six NTG patients (56 eyes) with an ICS and 103 NTG patients (103 eyes) with an IPS were included. Retrospectively, the differences were assessed between the two groups for baseline characteristics, ocular factors, systemic factors, and lifestyle factors. Also, the mean deviation of visual field was compared between the two groups. RESULTS: Patients from both ICS and IPS groups were of similar age, gender, family history of glaucoma, and follow-up periods. Frequency of disc hemorrhage was significantly higher among patients with ICS than in patients with IPS. Moreover, systemic risk factors such as hypotension, migraine, Raynaud's phenomenon, and snoring were more prevalent in the ICS group than in the IPS group. There were no statistical differences in lifestyle risk factors such as smoking or body mass index. Pattern standard deviation was significantly greater in the ICS group than in the IPS group, but the mean deviation was similar between the two groups. CONCLUSIONS: NTG Patients with ICS and IPS have different profiles of risk factors and clinical characteristics. This suggests that the pattern of initial visual field loss may be useful to identify patients at higher risk of central field loss.
Female ; Humans ; Incidence ; *Intraocular Pressure ; Low Tension Glaucoma/*complications/diagnosis/physiopathology ; Male ; Middle Aged ; Optic Disk/*pathology ; Republic of Korea/epidemiology ; Retrospective Studies ; Risk Assessment/*methods ; Risk Factors ; Scotoma/diagnosis/*epidemiology/etiology ; Visual Fields/*physiology

PURPOSE: To investigate anterior segment parameters in obese patients in comparison to healthy individuals. METHODS: Thirty-four obese subjects and 34 age-sex-matched healthy subjects were enrolled in this prospective cross-sectional study. Ophthalmological examinations including intraocular pressure (IOP), central corneal thickness (CCT), anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), and axial length (AL) measurements were performed on each subject. Height and weight of all subjects were recorded and body mass index (BMI) was calculated. RESULTS: IOP was significantly higher in the obese group (p = 0.003). The mean ACD in obese subjects was significantly lower than that in control subjects (p = 0.036). AL, ACV, ACA and CCT were not significantly different between the groups. There was a positive correlation between BMI and IOP (r = 0.404, p < 0.001). ACD and ACA were negatively correlated with BMI. CONCLUSIONS: IOP was significantly higher and ACD was significantly lower in obese subjects. AL, ACV, ACA and CCT were not significantly different between the groups. The impact of obesity on anterior chamber parameters should be further investigated.
Adult ; Aged ; Anterior Chamber/*pathology/physiopathology ; Cross-Sectional Studies ; Female ; Humans ; Intraocular Pressure/*physiology ; Male ; Middle Aged ; Obesity/*diagnostic imaging ; Prospective Studies ; Tomography, Optical Coherence/*methods ; Tonometry, Ocular