Observation seasonal variation of intraocular pressure in young healthy volunteers

AIM:To investigate fluctuation of intraocular pressure(IOP)and seasonal variation of 24-hour IOP during one year in healthy participantsMETHODS:Totally 13 young healthy volunteers participated in this study.IOP was measured with Canon TX-20 at about 8:00-9:00 a.m.from Monday to Friday every week for a whole year.They also underwent 24-hour IOP examination every three months.Blood pressure,heart rate,temperature,humidity,atmosphere pressure,sunshine duration and other environment parameters were recorded.RESULTS:The yearly fluctuation curve showed IOP in the summer months were lower than other seasons.In the multivariable generalized estimating equation analysis,IOP had a negative correlation with both temperature and sunshine duration(P<0.05).There also was a seasonal effect on 24-hour IOP.However,all intraclass correlation coefficients values of minimum,maximum and average of the 24-hour IOP and each individual IOP were less than 0.30.CONCLUSION:IOP is trend to be higher in cold days than warm days.IOP have negative association with both environmental temperature and duration of sunshine.On a season-to-season basis,24-hour IOP is not highly reproducible in healthy volunteers.     

高眼压症患者的随访观察

目的:探讨高眼压症的危险因素、随访指标。方法:对29例高眼压症患者进行3～4(平均3.5)a的随访,随访内容包括眼压、视野、视盘及视神经纤维层等方面的检查。结果:随访过程中25例患者眼压无明显变化,2例眼压呈下降趋势,眼压增高2例。结论:高眼压症与多种致病因素有关,应密切随访观察,出现可疑青光眼改变,积极行抗青光眼的治疗。     

The effect of lateral decubitus position on intraocular pressure in healthy young subjects

Purpose: To investigate the effect of change of body posture from supine to lateral decubitus position (LDP) on intraocular pressure (IOP) in healthy young subjects. Methods: We evaluated 38 eyes of 19 healthy young Korean subjects. IOP was measured using Tonopen XL^® in both eyes in the sitting and supine position, 5 and 30 min after right LDP and 5 min after returning to the supine position. A week later, IOP was measured in the same sequence except that the subjects assumed the left LDP. The eye on the lower side in the LDP was termed as a dependent eye. Results: The mean IOP of the dependent eyes increased significantly at 5 min after changing from supine to right (16.26 ± 2.73 mmHg versus 18.54 ± 2.95 mmHg, p < 0.01) or left LDP (15.53 ± 2.41 mmHg versus 17.53 ± 3.37 mmHg, p < 0.01); this IOP increase in the dependent eyes persisted at 30 min after changing to right (18.47 ± 2.97 mmHg, p < 0.01) or left LDP (17.79 ± 2.20 mmHg, p < 0.01). Upon returning to the supine position, IOP of the dependent eyes decreased significantly (16.83 ± 2.67 mmHg, p < 0.01 for right LDP and 16.47 ± 2.32 mmHg, p < 0.01 for left). However, this effect of the positional change was not found in the non‐dependent eyes (all, p > 0.05). Mean IOP in the dependent eye was significantly higher than that in the non‐dependent eye at 30 min after changing to the right (+0.89 ± 1.52 mmHg) or left LDP (+1.84 ± 2.03 mmHg). Conclusion: The postural change from supine to LDP significantly increased IOP of the dependent eyes.     

Comparison of intraocular pressure measurements with different contact tonometers in young healthy persons

AIM: To analyze the correlation of Goldmann applanation tonometer (GAT), I-Care tonometer and Tono-Pen tonometer results in young healthy persons, and to investigate the influence of central corneal thickness (CCT) on intraocular pressure (IOP) measurements recorded with these tonometers. METHODS: We conducted a pilot clinical study in 78 eyes of 78 subjects aged 22-28 years old (44 women and 34 men; mean age 23.8±1.19y). IOP was measured using GAT, I-Care and Tono-Pen tonometers, followed by measurements of CCT. Statistical analysis was performed using SPSS 20.0. RESULTS: The mean IOPs and standard deviation (±SD) for GAT, I-Care and Tono-Pen were 15.62±2.281 mm Hg, 16.29±2.726 mm Hg and 16.32±2.393 mm Hg, respectively. The mean CCT was 555.15±29.648 μm. Clear positive correlations between GAT and I-Care, GAT and Tono-Pen, and I-Care and Tono-Pen tonometers were found (r=0.867, P<0.001; r=0.861, P<0.001; r=0.915, P<0.001, respectively). In comparison between devices, Bland–Altman analysis showed a significant mean difference (MD) in the measurements by GAT and I-Care of ?0.679 mm Hg and by GAT and Tono-Pen of ?0.705 mm Hg ( P<0.001), but there was no significant difference between I-Care and Tono-Pen ( P>0.05). Both non-gold standard tonometers were affected by CCT; that is, both I-Care and Tono-Pen tonometer values were significantly higher with higher CCT means (>555 μm; MD=?1.282, P<0.001; MD=?0.949, P<0.001, respectively) compared with GAT. CONCLUSION: Both I-Care and Tono-Pen tonometers overestimated IOP compared with the GAT values. Either the I-Care or Tono-Pen tonometer could be used instead of GAT because there was no significant difference between their results. Higher CCT values (>555 μm) were associated with overestimated IOP values.     

Effect of sildenafil citrate on intraocular pressure and blood pressure in human volunteers

Anecdotal reports have suggested that the vasodilator, sildenafil citrate, which evokes its effect via a select inhibition of PDE5, has the potential to increase intraocular pressure (IOP) in some individuals. An ocular hypertensive effect by sildenafil was also recently described in a sheep animal model. In contrast, clinical studies have not found a direct association between sildenafil ingestion (commonly consumed as Viagra) and changes in IOP. However, some such studies also reported no effects of sildenafil on systemic blood pressure (BP) at the time of the IOP determination. Given this surprising result, our purpose was to repeat a study in human volunteers in the city of Corrientes, Argentina to corroborate the effects of sildenafil on human IOP and systemic BP. For the present study, 9 healthy volunteers (male and female, 18–74 years old) were selected as subjects after ophthalmic and cardiovascular evaluation indicated that they exhibited normal parameters for their age. In a masked, placebo-controlled study, the subjects ingested 100 mg sildenafil citrate (provided as Vorst from Laboratorios Bernabo, Argentina) in one session, and a placebo on a second separate occasion. IOP was measured with a Goldman applanation tonometer by an ophthalmologist, and BP by a second physician, neither of whom witnessed the tablet ingestion by the volunteers, nor provided with information on the nature of the test compounds. A third individual administered the tablets. The average baseline IOP of this group of 9 was 13.1 ± 0.6 mm Hg. Subsequent to sildenafil ingestion, IOP increased by 26% to 16.5 ± 0.8 mm Hg 60 min later (P < 0.005, as paired data), and returned to control values within 2 h. Both systolic and diastolic BP were significantly reduced by sildenafil ingestion. At the point of maximal systemic hypotension (90 min), the systolic and diastolic pressures declined by 15% and 13%, respectively. No significant changes in IOP or BP were recorded after ingestion of the placebo. Our results suggest that sildenafil can elicit a transient IOP increase that may be of importance to patients chronically treated with PDE5 inhibitors for various vascular diseases (e.g., pulmonary hypertension). We discuss possible mechanisms by which PDE5 inhibition might lead to a rise in IOP.     

Nocturnal blood pressure and intraocular pressure measurement in glaucoma patients and healthy controls

Daytime and nocturnal intraocular pressure (IOP) values and systemic blood pressure (BP) values were compared in 60 non-glaucomatous controls, 54 glaucoma patients with normal visual field, and 46 glaucoma patients with visual field loss. The daytime IOP was measured with a Goldmann applanation tonometer and the nocturnal IOP with a Bio-Rad-Tono-Pen 2 . The BP was measured with either a mercury manometer or with a Meditech ABPM-02 Ambulatory Blood Pressure Monitor, which took BP readings at 60 minute intervals. A tendency towards increasing IOP and decreasing BP was detected in the non-glaucomatous controls, within normal limits, and pathological changes of IOP and BP were observed with a significantly high occurrence (5% > P > 2%; Pearson's ²-test) in the glaucoma group with visual field loss.     

Diurnal and seasonal variations in intraocular pressure in the rabbit

The diurnal variations in intraocular pressure in the rabbit were measured during a period of 12 months in a cross-sectional study. The average intraocular pressure of all the measurements taken during the year was 19.6 +/- 2.0 mmHg (mean +/- S.D.; n = 1957). The daily curve showed a continuous rise during the day from 18.2 +/- 1.7 mmHg (n = 175) at 0800 hr to 20.6 +/- 1.8 mmHg (n = 167) at 1700 hr. During the month of June, when the measurements were extended until midnight, this rise in intraocular pressure continued until 2200 hr, reached a level of 22.5 +/- 1.6 (n = 16), and started to decline. A similar daily pattern was observed throughout the year. The annual curve showed two peaks, during the summer and winter seasons, with a daily average of 20.2 +/- 2.1 (n = 404) and 20.2 +/- 2.0 (n = 638) respectively. The lowest average daily IOP value was obtained during the spring and was 18.8 +/- 2.0 (n = 509). An intermediate level between the summer/winter and the spring values was obtained during the autumn and was 19.4 +/- 1.7 (n = 406).     

非接触眼压计测量高眼压兔模型的准确性

目的:探讨非接触眼压计(NCT)测量高眼压兔模型的准确性。方法:兔全身麻醉后前房、玻璃体腔穿刺,通过平衡盐水柱高低调控眼内压,前房插管显示实际眼压于15.00±0.50,20.00±0.50,25.00±0.50,30.00±0.05,35.00±0.50,40.00±0.50,45.00±0.50mmHg,同时测量相对应的NCT眼压。分析实际眼压与NCT眼压的差异及相关性,以实际眼压作为应变量进行回归分析。结果:兔NCT眼压均低于实际眼压值,有显著性差异(P<0.01)。兔NCT眼压与实际眼压两者具有显著相关性(相关系数r=0.985,P<0.01)。筛选回归方程Y=10.875+1.170X(方差分析F=2691.389,P<0.01),式中Y为实际眼压,X为NCT眼压。结论:NCT能够用于测量高眼压兔模型,实际眼压与NCT眼压之间有直线关系,可借助回归方程通过NCT眼压推断实际眼压,为兔青光眼模型眼压测量提供了实验支持。     

北京与西藏地区青壮年人群眼压分布特点比较

目的探讨不同地区人群眼压分布特征以及海拔高度对眼压的影响,为青光眼防治提供流行病学资料。方法分别选择北京和西藏地区20～50岁青壮年志愿者,我们选取北京地区受试者共56人,其中男35人,女21人,平均年龄为33.1岁;西藏地区受试者共62人,其中男37人,女25人,平均年龄为36.0岁。对所有入选者进行视力、眼压、前房深度及眼底杯盘比检查,采用非接触眼压计测量24h眼压,取右眼眼压测量值,应用统计学方法分析北京和西藏地区受试者昼夜眼压曲线峰值、谷值及均值间是否存在差异。结果所有患者均取右眼眼压值作为观测值,结果显示,北京地区人群眼压峰值为(21.68±4.04)mmHg(1kPa=7.5mmHg),谷值为(16.49±2.81)mmHg,均值为(18.87±3.20)mmHg;西藏地区人群眼压峰值为(14.24±2.84)mmHg,谷值为(11.03±1.38)mmHg,均值为(12.50±2.01)mmHg;北京和西藏两地人群眼压峰值、谷值及均值比较,差异均有统计学意义(均为P<0.01)。结论平原与高原地区人群眼压存在差异,高原地区人眼压值低于平原地区。     

Age variations in intraocular pressure in a cohort of healthy Austrian school children

Purpose

Limited data exist detailing the normal range of intraocular pressure (IOP) for healthy school age children. This study aims to describe the mean and normal range of IOP measurements that may be expected using the Icare rebound tonometer and to examine associations between visual function measures and IOP.

Methods

Six measurements of IOP from each eye were obtained from 211 normal children aged 6–15 years (79 females and 132 males) using the Icare tonometer. Other measures of visual function obtained included: visual acuity, non-cycloplegic retinoscopy, amplitude of accommodation, accommodative facility, and accommodative response.

Results

Statistical analysis (Mann–Whitney U test) demonstrated that the male subjects were more likely to have higher IOP measurements than the female subjects (mean IOP males 15.02 mm Hg (SD 2.19), mean IOP females 14.44 (SD 2.01) P=0.041). Analysis (Spearman''s rho) showed a statistically significant association between age and IOP (right eye) in males (P<0.001) but no association for females (P=0.459). Using Spearman''s rank analysis, statistically significant associations were found between IOP and amplitude of accommodation in males, for the whole data set (P=0.09) and for data up to age 11 (P<0.001). For females no statistically significant association was found for the whole data set (P=0.253) or for data up to age 11 (P=0.08). IOP was not significantly associated with visual acuity, refractive error, accommodative facility, or accommodative response.

Conclusion

This study provides useful normative IOP data using the Icare tonometer for a European cohort of school age children.     

高眼压状态下青光眼小梁切除术的临床分析

目的：探讨青光眼高眼压状态下小梁切除术的安全性和有效性。

方法：对25例26眼充分降眼压后眼压仍不正常的青光眼患者, 前房穿刺放出房水后行复合小梁切除术,观察疗效及术后并发症。

结果：所有手术均顺利完成, 未出现暴发性脉络膜出血、玻璃体脱出等严重并发症,术后眼压控制≤21mmHg,术后视力提高25眼,总有效率96.2%。

结论：小梁切除术治疗青光眼安全、简便、可靠。对药物不能控制的持续性高眼压状态下的青光眼,放出房水后再行复合小梁切除术仍是最有效的理想术式。     

Intravenous hypertonic saline to reduce intraocular pressure

Purpose: To quantitate the effect of intravenous hypertonic saline (IVHTS) injection on elevated intraocular pressure (IOP). Methods: Nineteen patients (median age, 65 years; range, 41–84 years) with glaucoma and an IOP 30 mmHg or higher were recruited. A bolus of IVHTS (sodium chloride concentration 23.4%) was injected in an antecubital vein over 10–20 seconds. The IOP and systolic and diastolic blood pressure (BP) were measured frequently for 2 hr. The dosage was 0.5 mmol/kg sodium in 11 patients (Group 1) and 1.0 mmol/kg in eight patients (Group 2). Results: In both groups, a median absolute IOP reduction of 7 mmHg was achieved in 5 min. The maximum median reduction was 7 mmHg (range, 4–16) and 9 mmHg (range, 3–14) at 5 and 16 min after IVHTS in Group 1 and 2, respectively, at which point the median IOP had reduced from 38 and 35 mmHg to 31 and 27 mmHg (p < 0.001), respectively. In both groups, the IOP remained 7 mmHg reduced 2 hr after IVHTS. Systolic BP increased a median of 14.5 mmHg at 3 min and was comparable with baseline after 6 min. Conclusion: Intravenous hypertonic saline solution reduces IOP moderately within minutes for up to 2 hr.     

New perspectives on target intraocular pressure

The evidence in support of intraocular pressure (IOP) lowering to reduce risk of glaucoma onset or progression is strong, although the amount and quality of IOP reduction is less well defined. The concept of a target IOP includes a percentage reduction, calculated IOP, or a predetermined IOP figure or range. Yet none of these strategies have been validated. In addition, our understanding of the way IOP influences glaucoma risk is continuously evolving. Examples of this include the data on IOP fluctuation and lamina cribrosa and cerebrospinal fluid pressure differentials. That these variables are not included in target IOP calculation potentially undermines its accuracy and usefulness. We summarize the evidence for target IOP, new developments in our understanding of IOP and glaucoma pathogenesis, as well as emerging strategies for setting targets and assessing response to treatment.     

角膜中央厚度与眼压读数

目的　探讨角膜中央厚度与眼压读数的关系。方法　对44例88眼屈光角膜手术前的患者,分别用压平眼压计和超声角膜测厚仪进行角膜中央厚度和眼压的测量,并对二者之间的关系进行统计分析。结果　Ⅰ组角膜中央厚度≥580μm,眼压为21.50～27.00mmHg(23.70mmHg±1.36mmHg)(1kPa=7.5mmHg),屈光度-2.00～-12.00D。Ⅱ组角膜中央厚度＜520μm,眼压为11.00～20.00mmHg(15.66mmHg±1.71mmHg),屈光度-1.25～-11.25D。Ⅰ组眼压高于Ⅱ组（P＜0.001）。结论　角膜厚度与眼压有明显的相关性,即角膜厚度增加眼压相应增高,当眼压读数高于正常时,应考虑到是角膜中央厚度的改变。     

传导性角膜成形术后眼内压的变化

目的:探讨传导性角膜成形术(CK)对眼压测量可能影响。方法:在术前和术后第1wk,第4wk,分别用非接触式眼压计(NCT)、Goldmann眼压计(GAT)和Schiotz眼压计测量接受CK治疗的20例36眼的眼压,所得结果采用SPSS11.5软件进行统计分析。结果:和术前比较,CK术后NCT、GAT以及Schiotz眼压计测量值显著降低。眼压变化和年龄、性别、角膜曲率以及拟矫正屈光度无关。结论:CK术后压平式眼压计测量眼压值偏低。     

Damping of intraocular pressure fluctuations

Background: There is increasing evidence that relatively rapid spikes in intraocular pressure may contribute to axonal damage in glaucoma. The present study seeks to quantify the ability of a compressible damping element (a simple air bubble) to reduce intraocular pressure fluctuations induced by a known change in intraocular fluid volume. Methods: A mathematical model describing the damping of intraocular pressure increases for a given infusion volume was developed and compared with experimental data obtained from isolated pig eyes. A damping element (100 µL to 2 mL of air) was added to the system, and the effect on the induced intraocular pressure change for a given infusion volume was assessed. Results: The introduction of the damping element reduced the intraocular pressure change in a volume‐dependent manner consistent with the mathematical modelling. The maximum bubble size tested (2 mL) dampened the intraocular pressure change by an average of 63.5 ± 8.7% at a baseline pressure close to 20 mmHg. Close agreement was seen between the mathematical model and the experimental data. Conclusion: Mathematical modelling and experiments in isolated pig eyes demonstrated that the addition of a damping element in the form of a compressible air bubble is capable of significantly reducing induced intraocular pressure spikes.     

粘弹剂对人工晶状体植入术后的眼压影响

目的 探讨粘弹剂对人工晶状体植入术后的眼压影响。方法 总结分析５３７例使用２％ＨＰＭＣ的人工晶状体植入术后的眼压变化情况。结果 术后眼压升高的２３．６５％,与性别、年龄无关。结论 粘弹剂对人工晶状体术后眼压有一定的短期影响。     

血液透析后眼压与颅内压的变化

血液透析是救治急、慢性肾衰竭及其他一些严重疾病的重要方法。研究显示,血液透析会引起眼压、颅内压的变化。对透析过程中眼压和颅内压变化的研究,可能为建立青光眼发病模型提供新的思路,有助于青光眼视神经损害的研究。本文就血液透析后眼压及颅内压的变化作一综述。     

可疑房角关闭24 h眼压变化规律的观察

目的：通过24 h眼压测量对可疑房角关闭眼（ PACS）的眼压变化规律进行观察。方法收集2014年7月至2015年12月诊断为可疑房角关闭的患者43例（86只眼）以及正常志愿者46例（92只眼）。从7 am起每隔2 h测量1次进行24 h眼压监测。结果两组之间峰值眼压的分布差异无统计学意义（χ2＝3．367, P ＞0.05）,均主要集中在1am～7am,门诊时间的峰值眼压出现比率只有36．5％。 PACS组平均谷值眼压和日间的平均眼压与正常组的差异无统计学意义（ t ＝1．754,0.959,均P ＞0.05）,而平均峰值眼压、平均眼压的波动值和夜间的平均眼压均高过正常组,差异具有统计学意义（ t ＝4．450,7．751,4．382,均P ＜0.05）。结论相对于正常眼,可疑房角关闭眼眼压的变化范围更大,峰值的眼压和夜间的眼压水平更高。24 h眼压的检查可以为可疑房角关闭的诊疗提供可靠的依据。     

高眼压下青光眼的手术治疗

目的探讨高眼压下行青光眼复合式小梁切除术的疗效.方法对33例(33只眼)应用药物不能控制眼压的青光眼患者,采取术中先缓慢降压的方法,进行复合式小梁切除术.结果术后视力提高20只眼,占60.61%,视力不变8只眼,占24.24%;术后眼压控制≤21mmHg21只眼,占66.67%,局部用药可控制者9只眼,占27.27%.结论对药物不能有效控制眼压的青光眼患者,在高眼压下采取必要措施,进行复合式小梁切除术是可行的.