Intraocular Pressure In Group Research Articles

Correlation between Systemic Oxidative Stress and Intraocular Pressure Level.

BackgroundThe involvement of local and systemic oxidative stress in intraocular pressure (IOP) elevation and optic nerve damage has been hypothesized in the pathogenesis of glaucoma. We reported previously that the level of systemic antioxidative capacity is lower in patients with open-angle glaucoma than controls without glaucoma. Here, we assessed the correlation between IOP and systemic levels of prooxidants and antioxidants by analyzing the blood biochemistry in patients with glaucoma.MethodsPeripheral blood samples were collected from Japanese patients with primary open-angle glaucoma (n = 206), exfoliation syndrome (n = 199), and controls (n = 126). Serum levels of lipid peroxides, ferric-reducing activity, and thiol antioxidant activity were measured by diacron reactive oxygen metabolite (dROM), biological antioxidant potential (BAP), and sulfhydryl (SH) tests, respectively, using a free radical analyzer. To test the possible effect of oxidative stress on IOP levels, the patients were classified into one of four groups (Q1, Q2, Q3, and Q4, with Q1 having the lowest IOP) based on the quartile value of IOP. For this classification, the known highest IOP value in both the right and left eyes was regarded as each subject’s IOP. For comparisons among the IOP groups, the differences were calculated using one-way analysis of variance followed by post-hoc unpaired t-tests. To adjust for differences in demographic characteristic distributions, the dROM, BAP, and SH test values were compared among the IOP groups using multiple logistic regression analysis; the odds ratio (OR) of each variable was calculated with the Q1 group as the reference.ResultsThe dROM and the SH levels did not differ significantly (p = 0.6704 and p = 0.6376, respectively) among the four IOP groups. The BAP levels differed significantly (p = 0.0115) among the four IOP groups; the value was significantly lower in the Q4 group (1,932 μmol/L) compared with the Q1 (2,023 μmol/L, p = 0.0042) and Q2 (2,003 μmol/L, p = 0.0302) groups and significantly lower in the Q3 group (1,948 μmol/L) than the Q1 (p = 0.0174) group. After adjustment for differences in various demographic characteristics, lower BAP values were significantly associated with the classification into higher IOP groups (Q3 group, p = 0.0261 and OR = 0.06/range; Q4 group, p = 0.0018 and OR = 0.04/range). The dROM and SH values did not reach significance in any comparisons.ConclusionsLower systemic antioxidant capacity measured by ferric-reducing activity is involved in the pathogenesis of open-angle glaucoma via its roles in IOP elevation.

Thermography

To evaluate the filtering bleb function after trabeculectomy using a new ocular surface thermography device. Thirty-five eyes of 35 patients after trabeculectomy were included in this prospective study. The filtering bleb function was tested with a new ocular surface-oriented, infrared radiation thermographic device in a noncontact manner (TG 1000). The eyes were classified into poorly controlled and well-controlled intraocular pressure (IOP) groups according to the patients' postoperative IOP. According to Kawasaki and colleagues, the mean temperature decrease in the filtering bleb (TDB) for evaluating bleb function was used, where TDB=(mean temperature of the temporal and nasal bulbar conjunctiva)-(mean temperature of the filtering bleb). Furthermore, the filtering bleb was evaluated during 10 seconds of eye opening and a new parameter was introduced, the TB10sec. TDB and TB10sec were analyzed statistically. The TDB was 0.911°C (±0.467) and the TB10sec was -1.027°C (±0.312) in the well-controlled IOP group. The TDB was 0.599°C (±0.499), and the TB10sec was -0.623°C (±0.265) in the poorly controlled IOP group, respectively. The difference in TDB (P=0.045), as well as that of TB10sec (P<0.001), between the well-controlled and poorly controlled IOP groups was significant. Temperature decrease in the filtering bleb provides information about its function. Because of the easy handling and reproducible measurements, thermography using Tomey TG 1000 may be a useful tool in the evaluation of filtering bleb function.

Ultrasound biomicroscopy findings in the area of previous surgical intervention in refractory glaucoma patients under topical ocular hypotensive therapy

to evaluate the effectiveness of different classes of topical hypotensive medications in refractory primary open-angle glaucoma (POAG), judging from structural changes in artificial pathways for intraocular fluid (IOF) visualized with ultrasound biomicroscopy (UBM). UBM analysis was performed in 104 eyes of 102 patients, mean age 68.4 ± 0.8 years, including 41 POAG patients with well controlled intraocular pressure (IOP) (group 1) and 41 refractory POAG patients with poorly controlled IOP (group 2), all under topical hypotensive therapy (prostaglandin analogues, beta blockers, carbonic anhydrase inhibitors, or combination drugs). The control group consisted of 20 patients, who maintained normal IOP after a single glaucoma surgery and did not require medical management. The following UBM parameters were evaluated: intrascleral cavity and filtering bleb heights and conjunctival and scleral flap thicknesses. Findings differed depending on the condition of IOF outflow pathways. Unlike the poorly controlled patients, UBM parameters in group 1 were comparable to those in the controls. The optimal control of postoperative IOP was achieved on combination therapy (a beta blocker plus a carbonic anhydrase inhibitor). In contrast to well controlled POAG patients, target values of IOP were not achieved in refractory POAG patients with either of the topical therapeutic measures. Moreover, intrascleral cavity and filtering bleb heights in these patients were reliably low (p ≤ 0.01), as confirmed by UBM analysis of the area of surgical intervention.

Risk Factors and Clinical Manifestations of Ocular Hypertension after Primary Repair of Open Globe Injury

Purpose: To investigate the risk factors and clinical manifestations of ocular hypertension (HTN) after repair of open globe injury (OGI). Methods: In a retrospective study of 284 patients who underwent primary repair of open globe injury at the day of trauma, best corrected visual acuity (BCVA) at the time of trauma and 6 months postoperatively, length of laceration, location of laceration and mean intraocular pressure (IOP) at 1 month after primary repair were analyzed. Presence of iris injury, lens injury, intraocular foreign body (IOFB) and vitreous hemorrhage (VH) were also analyzed. Ocular hypertension was defined as elevation of IOP greater than or equal to 21 mm Hg over 3 measurements. Results: Fourteen (4.93%) of 284 patients had ocular hypertension. BCVA (log MAR) at the time of trauma in the ocular HTN group was significantly worse than in the normal IOP group (2.43 ± 1.04 and 1.76 ± 1.30, respectively, p = 0.033). In the multivariate analysis, ocular HTN increased significantly with IOFB (p = 0.038; odds ratio [OR], 3.584; 95% confidence interval [CI], 1.075-11.941) and VH (p = 0.028; OR, 3.971; 95% CI, 1.157-13.624). BCVA increased significantly after repair in both groups and mean IOP was well controlled after medical therapy (9 eyes) or surgical treatment (5 eyes) in the ocular HTN group (28.1 ± 4.7 and 15.8 ± 3.8, respectively, p < 0.01). Conclusions: Ocular HTN increased significantly with IOFB and VH at the time of trauma after repair of OGI and can be effectively treated by medication or surgical approach. J Korean Ophthalmol Soc 2015;56(8):1242-1247

Risk Factors for Decompression Retinopathy After Glaucoma Surgery

To evaluate the risk factors for decompression retinopathy after glaucoma surgery. We reviewed the medical records of patients who underwent a trabeculectomy or Ahmed valve implantation and divided them into 2 groups by the development of decompression retinopathy. Various factors were compared between the 2 groups, including age, sex, glaucoma type, previous intraocular surgery, preoperative and postoperative intraocular pressure (IOP), refractive error, axial length, anesthesia, and systemic risk factors such as history of diabetes, hypertension, medication, and a laboratory examination including hemoglobin, hematocrit, platelet, prothrombin time (PT), and activated partial thromboplastin time (aPTT). The proportion of eyes with decompression retinopathy was 3.05% (21 of 688 eyes), and 50 control eyes were selected randomly. No significant differences were observed between the 2 groups in age, systemic disease, glaucoma type, anesthesia, or the incidence rate of postoperative hypotony. Preoperative maximum IOP and the change of IOP was higher (P=0.016, 0.019), PT and aPTT was prolonged (P=0.001, 0.006), and hemoglobin and hematocrit level was lower in patients with decompression retinopathy (P=0.005, 0.002). Preoperative maximum IOP and hemoglobin showed a significant association with the development of decompression retinopathy in a multivariate analysis (P=0.031, 0.040). No significant difference was observed between the 2 groups for IOP and visual acuity 6 months postoperatively. Patients with high preoperative IOP and hematologic abnormalities have a higher risk for developing decompression retinopathy. Surgeons should carefully assess the potential risks and pay close attention to sufficiently decrease IOP preoperatively.

Experiment study of anti-scarring effect of butyrylchitosan membrane in filtering surgery for rabbit ocular hypertension model

Objective To study the anti-scarring effect of butyrylchitosan membrane in filtering surgery for rabbit ocular hypertension model.Methods This is an experimental study.The left eyes of 45 rabbits were made into ocular hypertension animal model successfully by intracameral injection of 0.3 ml 0.3％ compound carbomer solution.The intraocular pressure achieved 30 mmHg to 40 mmHg(1 mmHg =0.133 kPa) 3 weeks after the injection.Then 45 eyes were divided into 3 groups randomly.The eyes in group 1 accepted trabeculectomy.The eyes in group 2 received trabeculectomy combined with the application of mitomycin C.The eyes in group 3 were treated by trabeculectomy combined with the implantation of butyrylchitosan membrane beneath the scleral flap.Every 3 rabits were euthanized at 1 week,2 weeks,4 weeks,8 weeks and 12 weeks postoperatively in each group and the eyeballs were examined.Results The pathological results of the eyeballs at 2 weeks postoperatively revealed that collagen fibers deranged with much infiltration of inflammatory cells in group 1,disorganized collagen fibers with shorter and broken collagen and less infiltration of inflammatory cells in group 2,collagen fibers arranged in neat rows with less infiltration of inflammatory cells in group 3.Two weeks postoperatively,the intraocular pressure of group 1 was beyond 21 mmHg,which was higher than that of group 2 and group 3 (F =392.869,P ＜ 0.05).At 12 weeks postoperatively,the intraocular pressure of group 3 was lower than that of group 1 and group 2 (F =259.923,P ＜ 0.05).The percentages of functional blebs in group 1 and group 2 decreased at 4 weeks after the surgeries.Conclusion Trabeculectomy combined with implantation of butyrylchitosan membrane beneath the scleral flap can prevent the proliferation of fibers and maintain the functional filtration,which will reduce the complications and increase the success rate of surgery. Key words: Butyrylchitosan; Mitomycin C; Trabeculectomy; Rabbit; Glaucoma

Heritabilities of Intraocular Pressure in the Population of Korea

Intraocular pressure (IOP) is the principal modifiable risk factor for the progression of primary open-angle glaucoma. Studies that have measured the IOP directly in large numbers of matched parent-offspring pairs are limited in Asian populations. To compare IOPs in parents and their offspring in Korea. Family-based cohort study examining data from the Korean National Health and Nutrition Examination Survey conducted between 2008 and 2009. Data were obtained from 9700 participants from Korea. Familial correlations for IOP were calculated in different types of relative pairs. Variance component methods were used to obtain heritability estimates. The individuals were stratified into 2 groups (those with and those without an IOP of ≥ 19 mm Hg; ie, high IOP group and nonhigh IOP group) based on the mean plus 2 SD IOP value of the entire study population. We evaluated the impact of parents' high IOP on offspring's high IOP. The relationship between parental systemic disease and high IOP in their offspring was also investigated. The mean (SD) IOPs in the right and left eyes were 13.90 (2.74) and 13.89 (2.74) mm Hg, respectively. Correlation coefficient estimates between parent-offspring pairs, sibling pairs, and spouse pairs for IOP were significant as 0.19, 0.31, and 0.29 (P < .001, P = .001, and P < .001, respectively). The total variance of the phenotype under study was explained by 2 sources of variation, additive genetic (36% [95% CI, 32%-40%]) and unique environment (64% [95% CI, 60%-68%]). The risks of high IOP conferred by parents' high IOP were found to be significant for participants whose parents had high IOP (odds ratio, 9.76 [95% CI, 2.16-44.12]). In this study, high IOP was not associated with parental diabetes mellitus, hypertension, obesity, or metabolic syndrome. Intraocular pressure showed a significant heritable tendency from parents to their offspring with a heritability estimate of 0.36 in Asian populations. The risk of high IOP was significantly increased in participants whose parents had high IOP. This has potential implications for the screening of family members of patients with ocular hypertension and glaucoma.

Effect of high pressurization versus normal pressurization on changes in intraocular pressure immediately after clear corneal cataract surgery

To compare changes in intraocular pressure (IOP) immediately after clear corneal incision (CCI) cataract surgery between eyes in which IOP was adjusted to a high or normal range at the conclusion of surgery. Hayashi Eye Hospital, Fukuoka, Japan. Comparative case series. Either eye of patients scheduled for phacoemulsification was randomized to 1 of 2 groups as follows: eyes that were to be adjusted to (1) high IOP (22 to 40 mm Hg) or (2) normal IOP (10 to 21 mm Hg). The IOP was measured using a rebound tonometer preoperatively; at the conclusion of surgery; and 15, 30, 60, 120, and 180 minutes and 24 hours postoperatively. The Seidel test and anterior segment optical coherence tomography (AS-OCT) were performed. The mean IOP at the conclusion of surgery was 31.3 mm Hg in the high IOP group and 17.1 mm Hg in the normal IOP group. The IOP decreased to approximately 15 mm Hg by 15 minutes and did not change until 60 minutes in either group. The mean IOP did not differ significantly between groups throughout the observation period (P ≥.0634). Hypotony of 5 mm Hg or less was not detected in any eye. The Seidel test was negative and based on AS-OCT, the wound was closed at 60 minutes in all eyes. After adjusting IOP to a high or normal range, the IOP normalized within 15 minutes postoperatively and was stable for 24 hours. The wound was closed within 60 minutes postoperatively.

Comparison of IOPen rebound tonometer with Goldmann applanation tonometer at different IOP levels.

To compare the accuracy of IOPen rebound tonometer with Goldmann applanation tonometer (GAT) in individuals with low, normal and high intraocular pressure (IOP) and to evaluate the effect of central corneal thickness (CCT) on IOP measurements. This cross-sectional study consisted of 159 participants. IOP of one eye of each subject was measured consecutively with IOPen and GAT. Then CCT was measured using an ultrasonic pachymeter. Based on GAT IOP readings, participants were divided into low, normal and high IOP groups. Correlation between tonometers and CCT was calculated by spearman's correlation coefficient. Agreement between tonometers was evaluated using Bland-Altman method. Non-significant underestimation of IOP by IOPen was observed in low IOP group (Mean difference: 0.20mmHg; P=0.454) and also in normal IOP group (Mean difference: 0.56mmHg; P=0.065). However, IOPen significantly overestimated IOP in high IOP group (Mean difference: 1.06mmHg; P=0.038). The 95% limits of agreement (LoA) width between IOPen and GAT IOPs were 7.84, 8.57 and 14.27mmHg in low, normal and high IOP groups, respectively. Low IOP group had thinner corneas compared to high IOP group (P=0.034). IOP measurements taken by IOPen were not influenced by CCT (P=0.099) while poor correlation between CCT and GAT was found (R=0.17, P=0.032). Using receiver operating characteristic (ROC) curve, cutoff value of 18.75mmHg was determined for IOPen with sensitivity of 98.1 and specificity of 97.2%. Accuracy of IOPen is comparable to GAT in patients with low or normal IOP but IOPen overestimates IOP at high IOP levels. CCT does not affect IOP readings with IOPen.

Increased Central Corneal Thickness in Patients with Turner Syndrome

To evaluate central corneal thickness (CCT) values in patients with Turner syndrome (TS) and compare these values with healthy subjects. A total of 31 subjects with TS and 67 age- and sex-matched healthy subjects made up the study and control group, respectively. The CCT values were measured by an ultrasound pachymeter in this cross-sectional prospective study. The ocular findings were recorded. We also evaluated to effect of karyotype analysis, recombinant growth hormone therapy (GHT), and mean duration of treatment on the CCT parameter in patients with TS. The mean CCT values were 582.0 ± 40.8 µm (490-648) in the TS and 549.1 ± 34.6 µm (494-601) in the healthy group. The mean intraocular pressure (IOP) by Goldmann applanation tonometry was 16.3 ± 3.1 mm Hg (9-22) in the TS and 15.2 ± 2.5 mm Hg (10-21) in the healthy group. The mean CCT value was significantly higher in the TS group (p<0.05) but there was no statistically significant difference between the 2 groups for IOP (p>0.05). There was also no significant difference for CCT regarding the karyotype, GHT use, and mean duration of treatment in patients with TS (p>0.05). Central corneal thickness values should be considered during measurement of IOP in individuals with TS as these values may be higher than in healthy subjects.

Micro-scale Stiffness Change of Cornea Tissues Suffered from Elevated Intraocular Pressure Investigated by Nanoindentation

Elevated intraocular pressure (IOP) is the main risk factor of glaucoma. In this study, an elevated IOP was introduced into the right eye balls of Sprague-Dawley rats, while their left eye balls were kept at a normal state. Nanoindentation showed that the elastic modulus of normal corneas was 2.75-3.33 MPa, whereas that of elevated IOP group was higher at 4.89-5.58 MPa. Scanning electron microscopy imaging suggested that the collagen fibrils subjected to the elevated IOP became thinner and with random directionality. It is believed the observed increase in elastic modulus should due to the strain-stiffening effects of collagen fibrils.

The effects of desflurane and sevoflurane on the intraocular pressure associated with endotracheal intubation in pediatric ophthalmic surgery

BackgroundFor ophthalmic surgery anesthesia, it is vital that intraocular pressure (IOP) is controlled. Most anesthetic drugs affect IOP dose-dependently, and inhalational anesthetics dose-dependently decrease IOP. In this study, we compared the effects of desflurane and sevoflurane on IOP and hemodynamics in pediatric ophthalmic surgery.MethodsThirty eight pediatric patients from the age of 6 to 15 years, who were scheduled for strabismus surgery and entropion surgery, were randomized to be administered desflurane (group D, n = 19) or sevoflurane (group S, n = 19). IOPs and hemodynamic parameters were measured before induction of anesthesia (B), after induction but immediately before intubation (AI), 1 min after intubation (T1), 3 min after intubation (T3), and 5 min after intubation (T5).ResultsThe mean arterial pressure (MAP) at T1 and heart rates (HRs) at T1 and T3 were significantly higher in group D than those in group S. There was no significant difference between the groups in IOP, cardiac index (CI) and stroke index (SI). There was a significant difference within the group in IOP, SI, MAP and HR. There was no significant difference within the group in CI.ConclusionsThere was no significant difference between the groups in IOP and hemodynamic parameters. The two anesthetic agents maintained IOP and hemodynamic parameters in the normal range during anesthetic induction.

Correlation between ocular perfusion pressure and ocular pulse amplitude in glaucoma, ocular hypertension, and normal eyes

BackgroundThe purpose of this study was to investigate the correlation between ocular perfusion pressure and ocular pulse amplitude in glaucoma, ocular hypertension, and normal eyes.MethodsNinety eyes from 90 patients were included. Thirty patients had been recently diagnosed with glaucoma and had no previous history of treatment for ocular hypotension, 30 had elevated intraocular pressure (IOP) without evidence of glaucoma, and 30 had normal IOP (<21 mmHg) with no detectable glaucomatous damage. Goldmann applanation tonometry (GAT), dynamic contour tonometry (DCT), blood pressure measurement, pachymetry, Humphrey visual field, and routine ophthalmic examination was performed in each patient. Ocular perfusion pressure was calculated as the difference between mean arterial pressure and IOP. The ocular pulse amplitude was given by DCT. The Pearson correlation coefficient was used to compare the glaucomatous and ocular hypertensive groups, and comparisons with the normal IOP group were done using the Spearman’s rank correlation coefficient.ResultsMean IOP by DCT was 22.7 ± 4.3 mmHg in the glaucoma group, 22.3 ± 2.8 mmHg in the ocular hypertension group, and 14.3 ± 1.6 mmHg in the control group. Mean IOP by GAT was 19.0 ± 5.1 mmHg for glaucoma, 22.4 ± 2.1 mmHg for ocular hypertension, and 12.9 ± 2.2 mmHg for controls. Mean ocular pulse amplitude was 3.4 ± 1.2 mmHg in the glaucoma group, 3.5 ± 1.2 mmHg in the ocular hypertension group, and 2.6 ± 0.9 mmHg in the control group. Mean ocular perfusion pressure was 46.3 ± 7.9 mmHg in the glaucoma group, 46.3 ± 7.9 mmHg in the ocular hypertension group, and 50.2 ± 7.0 mmHg in controls. No significant correlation between ocular perfusion pressure and ocular pulse amplitude was found in any of the groups (P = 0.865 and r = −0.032, P = 0.403 and r = −0.156, P = 0.082 and ρ = −0.307 for glaucoma, ocular hypertension, and normal eyes, respectively).ConclusionThere is no significant correlation between ocular perfusion pressure and ocular pulse amplitude values in glaucoma, ocular hypertension, or normal eyes. IOP values measured by GAT correlate with those measured by DCT.

Fixed-combination brimonidine–timolol versus latanoprost in glaucoma and ocular hypertension: a 12-week, randomized, comparison study

Objective:To evaluate the intraocular pressure (IOP)-lowering efficacy and safety of fixed-combination brimonidine 0.2%–timolol 0.5% compared with latanoprost 0.005% in patients with glaucoma or ocular hypertension.Research design and methods:This was a prospective, randomized, multicenter, investigator-masked clinical trial. After washout of any previous IOP-lowering medications, patients with IOP of 24 mmHg or higher were randomized to twice-daily fixed-combination brimonidine 0.2%–timolol 0.5% (n = 73) or once-daily latanoprost 0.005% (n = 75, dosed in the evening, with vehicle control in the morning to maintain masking) for 12 weeks. IOP was measured at 8 a.m. (before dosing), 10 a.m., and 3 p.m. at baseline, week 6, and week 12.Clinical trial registration:The trial is registered with the identifier 00811564 at http://www.clinicaltrials.gov.Main outcome measures:The primary efficacy endpoint was diurnal IOP (averaged over 8 a.m., 10 a.m., and 3 p.m.) at week 12. Safety measures included biomicroscopy.Results:There was no statistically significant difference between the treatment groups in mean diurnal IOP at baseline (p = 0.118). At week 12, the mean (SD) diurnal IOP was 17.8 (2.9) mmHg with brimonidine–timolol and 17.9 (3.9) mmHg with latanoprost (p = 0.794). The percentage of patients achieving at least a 20% decrease from baseline diurnal IOP at week 12 was 87.7% in the brimonidine–timolol group and 77.3% in the latanoprost group (p = 0.131). Measured biomicroscopic changes from baseline to week 12 were infrequent in both groups.Conclusions:Fixed-combination brimonidine–timolol was as effective as latanoprost in reducing IOP in patients with glaucoma or ocular hypertension. Both treatments demonstrated favorable ocular tolerability. The duration of the study was 12 weeks, and additional studies will be needed to compare the efficacy and safety of fixed-combination brimonidine–timolol and latanoprost during long-term treatment.

Distribution of Central Corneal Thickness and Intraocular Pressure in a Large Population of Turkish School Children

Purpose: To determine the distribution of central corneal thickness (CCT) and intraocular pressure (IOP) in a population of Turkish school children and to evaluate the relationships between these values and both age and gender.Methods: A total of 30,320 eyes from 15,160 healthy school children aged 5–18 years were examined. CCT and IOP were measured using an ultrasonic pachymeter and a non-contact tonometer, respectively. Measurements were compared with age, gender, and parental consanguinity of subjects.Results: The mean age of the school children was 10.43 ± 2.54 years. For right eyes, mean CCT was 557.91 ± 34.26 µm and mean IOP was 14.15 ± 2.87 mmHg. Mean CCT was significantly thicker in males compared to females (P < 0.0001). Mean IOP was significantly higher in females compared to males (P < 0.0001). CCT in children aged 14 years and older was significantly thinner than that in the younger age groups (P < 0.0001). There was a significant difference among the age groups for IOP (P < 0.05). No significant differences were observed in CCT or IOP related to parental consanguinity (P = 0.538, P = 0.319, respectively).Conclusion: Mean CCT in Turkish school children is of comparable thickness to that in Western school children. CCT reached adult values around 14 years of age in our children. Furthermore, males had thicker CCT than females. IOP was lower in males than females, and increased with age.

IOP Measured by Dynamic Contour Tonometry Correlates With IOP Measured by Goldmann Applanation Tonometry and Non-contact Tonometry in Japanese Individuals

The purpose of this study was threefold. We sought to compare the intraocular pressure (IOP) measured by dynamic contour tonometry (DCT) with that measured by Goldmann applanation tonometry (GAT) and noncontact tonometry (NCT). We also examined the influence of central corneal thickness (CCT) and corneal curvature radius (CCR) on the IOP measurements. Last, we investigated the factors that could affect the ocular pulse amplitude (OPA) measurements. Seventy-four patients with no history of intraocular surgery were enrolled in this study. We measured IOP by DCT, GAT, and NCT, and the CCT, CCR, and axial length (AL) in the right eye of each patient. We also measured OPA by DCT. We subsequently analyzed the correlation of IOP measurements between GAT and DCT and between NCT and DCT. We also examined the influence of CCT, CCR, and AL on IOP readings by the 3 tonometers. In addition, we investigated the factors that could affect the OPA measurements. The mean IOP measured by DCT was 2.8 mm Hg higher than that by GAT and 3.2 mm Hg higher than that by NCT. This difference was greater with thinner CCT in the lower IOP group than in the higher IOP group. IOP measurements by both GAT and NCT significantly correlated with CCT; however, IOP measurement by DCT did not correlate with CCT. No significant correlations were shown between the IOP measured by each of the 3 tonometers and either CCR or AL. OPA measurements positively correlated with age, IOP measurement by DCT, and pulse pressure. IOP measured by DCT correlates with IOP measured by GAT or NCT with a roughly 3.0 mm Hg higher value, and these differences were greater in the patients with a thinner CCT. IOP measurements by both GAT and NCT significantly correlated with CCT; however, IOP measurement by DCT did not correlate with CCT. Our findings also indicate that OPA measured using DCT shows a positive correlation with patient age, IOP measurement by DCT, and pulse pressure.

A comparative study about axial length measurement between IOLMaster and adjusted A-scan ultrasound methods in silicone-filled eyes

Background Combination of cataractopiesis with intraocular lens (IOL) is believed to improve the patient' s quality of life. However, 1OL power and axial length measured by traditional method in silicone-filled eye is normally bias to the actual levels. The optical coherence biometry technology has been widely used in the measurement of IOL, but little studies have been conducted to demonstrate the IOL power difference between those methods. Objective This study was to evaluate the predictability of IOL power calculations using the IOLMaster and adjusting contact ultrasound A-scan method in silicone oil-filled eyes. Methods Forty-four silicone-filled eyes of 42 patients were divided into 2 groups according to the intraocular pressure (IOP) ( group A: ≥ 10 mmHg group,29 eyes;group B:＜10 mmHg group, 15 eyes). IOLMaster and ocular ultrasonic measurement were used to measure the axis length before and after silicone oil was removed. The preoperatively measured eye axis and cornea curve were used to calculate the theoretical IOL. Results In normal IOP group ( T≥ 10 mmHg,29 eyes), the precision and stability of IOLMaster for axial length ( AL ) measurements and IOL power calculations were better than adjusted ultrasound A-scan( ZIOLMasterdependent = -2. 236, P = 0. 025 ), although in low IOP group ( T＜ 10 mmHg, 15 eyes),there were too much differences in axial length mesurement and IOL power calculation between the IOLMaster and adjusted ultrasound A-scan, so the post-operative imformation was not predicted accurately. Conclusion For anticipatory normal postoperative IOP eyes, the refractive outcome in cataract surgery in silicone oil-filled eyes can be predicted reliably and accurately with IOLMaster. But for complicated or anticipatory unstable postoperative IOP eyes,secondary implantation of IOL would be better. Key words: IOLMaster; Silicone oil tamponade; IOL power calculation; Axial length

Elevated Intraocular Pressure is a Common Complication During Active Microbial Keratitis

To determine the incidence, risk factor, and outcomes of elevated intraocular pressure (IOP) during active microbial keratitis. Retrospective cohort study. One hundred eighty-four patients with culture-proven microbial keratitis examined from January 2003 through December 2007 were included. High IOP was defined as IOP of 22 mm Hg or higher measured during the episode of active keratitis. The control group consisted of eyes with microbial keratitis whose IOP remained less than 22 mm Hg. Twelve factors were evaluated by univariate and multivariate analyses to determine whether any were associated with increased IOP. The incidence, risk factors, microbial profile, the necessity of therapeutic surgery, time to resolution, and final visual acuity were compared between the high IOP group and the control group. High IOP (mean, 29.1 mm Hg; range, 22 to 51 mm Hg) occurred in 52 (28%) of 184 patients with active corneal infection. Prior ocular surgery, diabetes mellitus, and ulcer size of 4.0 mm or larger were associated with IOP elevation (P ≤ .013). Surgical interventions were necessary in 19 (39%) of 49 patients in the high IOP group and in 14 (11%) of 129 patients in the control group (P < .0001). Time to ulcer resolution was longer in the high IOP group (mean, 50.1 ± 53.2 days) than in the control (mean, 31.6 ± 42.0 days; P = .005). Final visual acuity of 20/40 or better was achieved by more patients in the control group (47%) than in the high IOP group (20%; P < .001). Elevated IOP was detected in a significant proportion of patients with active microbial keratitis and was associated with poorer outcomes. Routine IOP check should be performed to avoid possible optic nerve damage.

Target intraocular pressure for stability of visual field loss progression in normal-tension glaucoma

To determine the target intraocular pressure (IOP) level in normal-tension glaucoma (NTG) for visual field (VF) stability following trabeculectomy. Forty eyes of 40 patients who underwent trabeculectomy were enrolled in this study. Progression was determined by a decrease in the Advanced Glaucoma Intervention Study VF defect score of four or more points. The Kaplan-Meier life table method was employed to compare the postoperative VF stability with predetermined IOP levels. The mean postoperative follow-up period was 12 years. At the final visit, the IOP was reduced from 15.2 to 9.4 mmHg on average (P < 0.0001). Reductions in IOP of 20% from baseline were achieved in 70.0% of eyes. The cumulative probability of VF stability was 92.7% in patients having an IOP reduction of >20%, whereas all patients in the poorly controlled IOP group showed progression (P < 0.0001). When IOP values of 9, 10, 11, and 12 mmHg were employed as the cutoff, the best VF prognosis was attained in eyes with a postoperative IOP of 10 mmHg. An IOP reduction of at least 20% from baseline or IOP <or=10 mmHg is recommended as the target postoperative IOP in progressive NTG.

Association between corneal hysteresis and central corneal thickness in glaucomatous and non‐glaucomatous eyes

We aimed to determine corneal hysteresis values (CH) using the ocular response analyser (ORA) in non-glaucomatous and glaucomatous eyes and their relationship with central corneal thickness (CCT). Corneal hysteresis, intraocular pressure (IOP) as measured by Goldmann applanation tonometry (GAT) and CCT were prospectively evaluated in 74 non-glaucoma subjects with IOP < 21 mmHg and in 108 patients with treated primary open-angle glaucoma (POAG). One eye in each subject was randomly selected for inclusion in the analysis. Mean (+/- standard deviation [SD]) age was 59.2 +/- 14.2 years in the non-glaucoma group and 62.4 +/- 9.8 years in the glaucoma group. Mean (+/- SD) GAT IOP was 15.7 +/- 2.65 mmHg and 16.38 +/- 2.73 mmHg in the non-glaucoma and glaucoma groups, respectively. There was no statistically significant difference between the two groups in mean age (p = 0.396) or mean GAT IOP (p = 0.098). Mean (+/- SD) CH was 10.97 +/- 1.59 mmHg in the non-glaucoma and 8.95 +/- 1.27 mmHg in the glaucoma groups, respectively. The difference in mean CH between the two groups was statistically significant (p < 0.0001). There was a strong positive correlation between CH and CCT in the non-glaucoma group (r = 0.743) and a significantly (p = 0.001) weaker correlation (r = 0.426) in the glaucoma group. Corneal hysteresis was significantly lower in eyes with treated POAG than in non-glaucomatous eyes. The corneal biomechanical response was strongly associated with CCT in non-glaucoma subjects, but only moderately so in glaucoma patients. It can be assumed that diverse structural factors, in addition to thickness, determine the differences in the corneal biomechanical profile between non-glaucomatous and glaucomatous eyes. Corneal hysteresis could be a useful tool in the diagnosis of glaucoma.