近视人群中角膜生物力学特性的分布

目的：分析伊朗近视眼及散光人群中角膜生物力学参数的分布特征。

方法：对接受激光矫正手术的近视眼及散光患者180眼进行前后节、显然验光等效球镜度、Orbscan II和Zywave全面的术前检查。用眼反应分析仪测量角膜滞后量,角膜阻力因子,模拟Goldmann眼压值及角膜补偿后眼压值。分析所有角膜生物力学的分布特性及其与显然验光等效球镜度、性别和年龄的相关性。数据采用SPSS 17软件进行统计学分析,以P<0.05为有显著性差异。

结果：平均年龄为28.20±6.78岁。平均显然验光等效球镜为-4.21±1.19D。平均角膜滞后量,角膜阻力因子,模拟Goldmann眼压值和角膜补偿后眼压值分别为10.00±1.28mmHg,10.17±1.45mmHg,15.71±2.67mmHg和 16.68±2.41mmHg。近视人群中,28.4%角膜滞后量约为10mmHg,71%从9mmHg增长到11mmHg。25.9%的近视人群的角膜阻力因子为10mmHg,48.7%为9mmHg增长到11mmHg。显然验光等效球镜与角膜滞后量(Rs=0.001,P=0.71)和显然验光等效球镜与角膜阻力因子(Rs=0.01,P=0.18)之间正相关性不明显。

结论：研究显示了伊朗近视眼人群中角膜生物力学的分布特征(角膜滞后量,角膜阻力因子,模拟Goldmann眼压值及角膜补偿后眼压值),并证实了角膜生物力学特性参数和显然验光等效球镜,年龄及性别之间没有统计学相关性。     

Reproducibility of viscoelastic property and intraocular pressure measurements obtained with the Ocular Response Analyzer

Purpose: To analyse the reproducibility of corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann‐correlated intraocular pressure (IOPg) and corneal‐compensated intraocular pressure (IOPcc) obtained with the ocular response analyzer (ORA). Methods: This is a prospective study, nonmasked, of eight successive examinations with the ORA device in 60 normal eyes. Using 30 eyes (one eye per subject), the reproducibility was assessed by comparing the first series of four examinations to the second four and by calculating the within‐subject coefficient of variation. The correlation and difference with the fellow eye were analysed, respectively. Results: The mean values were 10.7 ± 1.8 mmHg, CRF; 10.6 ± 1.6 mmHg, CH; 15.9 ± 3.9 mmHg, IOPg and 16.2 ± 3.7 mmHg, IOPcc. The reproducibility was significantly different for CRF (5.2 ± 5.9%), CH (7.3 ± 8.6%), IOPg (7.7 ± 6.7%) and IOPcc (10.1 ± 8.0%); p < 0.001. Considering the reproducibility, CRF correlated with CH (rs = 0.55; p < 0.001) and showed to be independent of IOPg and IOPcc. The score spread was best for CRF (2.6 ± 1.5 mmHg; 24.0%) compared to IOPg (4.3 ± 1.5 mmHg; 28.1%) and CH (3.1 ± 1.7 mmHg; 29.9%) and worst for IOPcc (5.5 ± 2.5 mmHg; 34.4%). The lowest difference with the fellow eye was observed for CRF (5.0%; p = 0.09). The correlation with the fellow eye was high, especially for IOPcc and CRF (rs > 0.9; p < 0.001) followed by IOPg and CH (rs > 0.8; p < 0.001). Conclusion: The ORA device provides reproducible information on viscoelastic properties of the cornea in normal eyes notably CRF and CH. IOPcc was less reproducible. Four measurements per eye were necessary to reach a 10% precision and six for 5%.     

Corneal biomechanical properties in normal‐tension glaucoma

Purpose: To investigate the intraocular pressure (IOP) and corneal biomechanical properties of normal and normal‐tension glaucoma (NTG) eyes. Methods: This study included 83 normal and 83 NTG eyes. We measured corneal‐compensated IOP (IOPcc), Goldmann‐correlated IOP (IOPg), corneal resistance factor (CRF), corneal hysteresis (CH) and central corneal thickness (CCT) three times each for normal and NTG eyes using an Ocular Response Analyzer (ORA). Results: No significant difference in CCT was seen between normal eyes (541.4 ± 26.8 μm) and NTG eyes (535.4 ± 24.9 μm; p = 0.16). IOPcc was significantly higher in NTG eyes (16.1 ± 2.6 mmHg) than in normal eyes (15.1 ± 2.9 mmHg; p = 0.01), while IOPg was significantly lower in NTG eyes (14.1 ± 2.7 mmHg) than in normal eyes (15.1 ± 3.0 mmHg; p = 0.04). CRF and CH were significantly lower in NTG eyes (CRF, 8.9 ± 1.5 mmHg; CH, 9.2 ± 1.3 mmHg) than in normal eyes (CRF, 10.6 ± 1.4 mmHg; CH, 10.8 ± 1.3 mmHg; p < 0.0001 each). Conclusion: IOPcc was significantly higher in NTG eyes than in normal eyes. The ORA may be useful for distinguishing between the IOPcc of NTG eyes with normal IOP and that of normal eyes. In addition, the ORA enables CRF and CH to be measured in vivo, and weakness of the lamina cribrosa may be clinically inferred from the fact that CRF and CH were reduced in NTG eyes in our study. Low CRF and CH may be clues to the pathology of NTG.     

Are There Any Changes in Corneal Biomechanics and Central Corneal Thickness in Fuchs’ Uveitis?

Purpose: To compare corneal biomechanics, intraocular pressure (IOP) and central corneal thickness (CCT) of 38 patients with unilateral Fuchs’ uveitis (FU) with 42 healthy controls.

Methods: Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated and corneal-compensated IOP (IOPg and IOPcc, respectively) and CCT were measured.

Results: The mean CH, CRF, and IOPg of the involved FU eyes were significantly lower (9.5?±?1.6, 9.0?±?1.9 and 13.1?±?4.3?mmHg) than contralateral eyes (10.1?±?1.7, 9.9?±?1.7 and 14.6?±?3.4?mmHg), and controls (10.5?±?1.5, 10.3?±?1.5 and 14.8?±?2.5?mmHg), respectively. There was no significant difference for mean IOPcc between involved FU or contralateral eyes and controls (14.8?±?4.1, 15.5?±?3.4 and 15.0?±?2.7?mmHg). The CCT values correlated with CH and CRF in the involved and contralateral eyes.

Conclusions: Involved FU eyes had lower CH, CRF, and IOPg than contralateral eyes and controls, with no difference regarding IOPcc.     

Corneal Biomechanical Characteristics in Patıents with Behçet Disease

Aim: To examine corneal biomechanical properties, intraocular pressure, and central corneal thickness in uveitic eyes with Behçet disease (BD) and to compare them with healthy controls. Methods: This study included 40 eyes of 34 patients with ocular BD and 20 eyes of 20 healthy controls. Eyes with ocular BD were subdivided into active and inactive groups. Ocular response analyzer (ORA) measurements were performed on the 20 eyes of 16 patients with active BD (group 1), 20 eyes of 18 patients with inactive BD (group 2), and 20 eyes of 20 healthy volunteers who served as the control group (group 3). Corneal hysteresis (CH), corneal resistance factor (CRF), intraocular pressure (Goldmann correlated [IOPg], and corneal compensated [IOPcc]) and central corneal thickness (CCT) values were recorded. Results: Mean age of patients in groups 1, 2, and 3 was 33.81?±?9.36, 32.38?±?9.08, and 31.05?±?5.85 years, respectively (p?=?0.76). Mean CH, CRF, IOPg, IOPcc, and CCT values in groups 1, 2, and 3 were [8.51?±?1.88, 9.72?±?2.11, 19.87?±?2.92, 16.13?±?3.29, and 592.50?±?39.95], [8.46?±?1.82, 8.45?±?1.98, 15.89?±?2.68, 15.35?±?2.91, and 528.35?±?19.18], and [8.47?±?1.48, 8.43?±?1.58, 15.59?±?2.74, 15.42?±?3.19, and 526.30?±?18.21], respectively [(p₁?=?0.040, 0.904, <0.001, 0.495 and <0.001 for CRF, CH, IOPg, IOPcc and CCT in group 1, respectively), (p₂?=?0.989, 0.904, 0.659, 0.989, and 0.989 for CRF, CH, IOPg, IOPcc and CCT in group 2, respectively), (p₃?=?0.989, 0.904, 0.660, 0.989, and 0.989 for CRF, CH, IOPg, IOPcc and CCT in group 3, respectively)]. Conclusion: CRF, IOPg, and CCT values altered in active BD group when compared with inactive BD and control group (p?相似文献   

Corneal biomechanical changes and intraocular pressure in patients with thyroid orbitopathy

AIM: To determine the relevance of the objective parameters addressing the altered biomechanical properties of cornea for glaucoma monitoring in patients with mild or moderate thyroid associated orbitopathy (TAO), and in healthy individuals. METHODS: Twenty-five patients with TAO (group 1) and 25 healthy adults (group 2) were included to the study. Both groups were of a similar age and the ratio women:man. For each patient, the following parameters of both eyes were measured with ocular response analyzer (ORA): corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann correlated intraocular pressure (IOPg) and corneal compensated intraocular pressure (IOPcc). In both groups participating in our study, all measurements were performed within minutes to reduce the diurnal effects. RESULTS: The mean age in group 1 was 56±11y and 76% were women, 24% were men. The mean age in group 2 was 64±11y and 68% were women, 32% were men. CH correlated negatively with IOPg in group 1 (r2=0.10, P<0.05). IOPg strongly correlated with IOPcc in both groups (group 1: r2=0.79, P<0.0001; group 2: r2=0.85, P<0.0001). There was positive correlation between CRF and IOPg in group 1 (r2=0.12, P<0.05) and in group 2 (r2=0.31, P<0.0001). Statistical analysis revealed no significant correlation between CRF and IOPcc in group 1 (r2=0.009, P>0.05) and also no significant correlation in group 2 (r2=0.04, P>0.05). CRF mean value in group 2 (11.51±1.72 mm Hg) was higher than in group 1 (10.85±1.45 mm Hg) (P<0.05). IOPg strongly correlated with IOPcc in both groups (group 1: r2=0.79, P<0.0001; group 2: r2=0.85, P<0.0001). There was also strong correlation between CRF and CH in both populations: group 1: (r2=0.58, P<0.0001), group 2: (r2=0.41, P<0.0001). CONCLUSION: Biomechanical parameters of cornea, as quantified by CH and CRF, and measured together with IOPcc, precisely reveal glaucoma staging in TAO and thus are reliable for diagnosing and follow-up in clinical practice.     

Effect of pathological myopia on biomechanical properties: a study by ocular response analyzer

AIM: To evaluate the ocular response analyzer (ORA) measurements of patients with pathological myopia in comparison with those of emmetropic control subjects, and to investigate the correlation between these ORA measurements and spherical equivalent (SE). METHODS: Measurements of 53 eyes of 53 subjects with pathological myopia (SE>-6.00 D) were compared with those of 60 eyes of 60 emmetropic controls. Corneal hysteresis (CH), corneal resistance factor (CRF), noncontact tonometer intraocular pressure (IOPg), and corneal-compensated IOP (IOPcc) were obtained for each subject. The refractive error value was determined as SE via a cycloplegic refraction test. RESULTS: The mean age was 54.1±18.9y (ranging from 5 to 88) in the pathological myopic group and 56.2±19.0y (ranging from 6 to 89) in the control group. There were no significant differences between the groups concerning age and sex. CH and CRF were significantly lower in the pathological myopic group than in the control group (P<0.001, P=0.005, respectively). IOPcc and IOPg were significantly higher in the pathological myopic group than in the control group (P<0.001, P=0.009, respectively). There were significantly positive correlations between CH and SE (r=0.565, P<0.001) and between CRF and SE (r=0.364, P=0.007). There were significantly negative correlations between IOPcc and SE (r=-0.432, P=0.001) and between IOPg and SE (r=-0.401, P=0.003). CONCLUSION: The present study displayed that pathological myopia affected biomechanical properties measured by ORA. The results of corneal biomechanical properties measured by ORA may need to be appreciated by taking refraction into account. Further, pathological myopia might be related with the increased IOP.     

Evaluation of corneal biomechanical properties following penetrating keratoplasty using ocular response analyzer

Purpose:

To evaluate corneal biomechanical properties in eyes that has undergone penetrating keratoplasty (PK).

Materials and Methods:

Retrospective observational study in a tertiary care centre. Data recorded included ocular response analyzer (ORA) values of normal and post-keratoplasty eyes [corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and cornea-compensated intraocular pressure (IOPcc)], corneal topography, and central corneal thickness (CCT). Wilcoxon signed rank test was used to analyze the difference in ORA parameter between post-PK eyes and normal eyes. Correlation between parameters was evaluated with Spearman''s rho correlation.

Results:

The ORA study of 100 eyes of 50 normal subjects and 54 post-keratoplasty eyes of 51 patients showed CH of 8.340 ± 1.85 and 9.923 ± 1.558, CRF of 8.846 ± 2.39 and 9.577 ± 1.631 in post-PK eyes and normal eyes, respectively. CH and CRF did not correlate with post-keratoplasty astigmatism (P =0.311 and 0.276, respectively) while a significant correlation was observed with IOPg (P =0.004) and IOPcc (P < 0.001).

Conclusion:

Biomechanical profiles were significantly decreased in post-keratoplasty eyes with significant correlation with higher IOP as compared with that in normal eyes.     

Corneal biomechanical characteristics in children with diabetes mellitus

To compare the corneal biomechanical properties in children with type 1 diabetes mellitus (DM) and healthy children. In this cross-sectional study, the study and control groups were composed of 68 children with DM and 74 healthy children, respectively. The corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg) and corneal-compensated intraocular pressure (IOPcc) were measured with the ocular response analyzer (ORA). Associations between ocular and diabetic parameters were also evaluated. There were no statistically significant differences between the two groups in age or gender distribution. The mean CH was 10.8 ± 1.5 and 10.7 ± 1.7 mmHg while the mean CRF was 10.9 ± 1.9 and 10.5 ± 1.6 mmHg in the diabetic group and control group, respectively. The mean IOPg was 15.9 ± 3.7 and 15.2 ± 3.4 mmHg, and the mean IOPcc was 15.8 ± 3.0 and 15.3 ± 3.4 mmHg in the diabetic and control group, respectively. There were no statistically significant differences between the two groups for CH, CRF, IOPg, and IOPcc measurements (independent t test, p = 0.624, p = 0.207, p = 0.263, p = 0.395, respectively). This study shows that type 1 DM does not have any effect on the corneal biomechanical parameters in childhood.     

Corneal biomechanical properties measured by the ocular response analyzer in acromegalic patients

Purpose

To investigate the effect of acromegaly on corneal biomechanical parameters.

Methods

This cross-sectional, comparative clinical study included 34 acromegalic patients and 30 age-matched and sex-matched healthy controls. Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated and corneal-compensated intraocular pressure (IOPg and IOPcc, respectively) were measured using the Ocular Response Analyzer. Central corneal thickness (CCT) was determined with the ultrasonic pachymeter.

Results

The mean duration of disease for the acromegalic patients was 5.3 years. There was no significant difference between the groups regarding mean CH, CRF, IOPg and IOPcc values. The respective mean values in patients with acromegaly and controls were 10.3?±?2.2 and 9.5?±?1.5 mmHg (p?=?0.13) for CH; 10.5?±?2.4 and 9.7?±?1.7 mmHg (p?=?0.16) for CRF, 16.1?±?3.6 and 15.5?±?2.9 mmHg (p?=?0.49) for IOPg, 16.8?±?3.4 and 17.0?±?2.8 mmHg (p?=?0.82) for IOPcc, and 544.8?±?32.2 and 530.7?±?22.9 μm (p?=?0.05) for CCT. A significant moderate correlation was detected between the duration of acromegaly and IOPg OD (r?=?0.430, p?=?0.01). There was no significant correlation between other ocular parameters and levels of GH and IGF-1 at the time of diagnosis, the status of control, adenoma type, radiotherapy treatment, and drug usage.

Conclusions

In acromegalic patients, the duration of disease was correlated with IOPg OD level. Corneal biomechanical parameters and CCT values were not significantly different than those in age-matched and sex-matched healthy individuals.     

Corneal biochemical features of patients with vernal keratoconjunctivitis

Background

Vernal keratoconjunctivitis (VKC) is a chronic, bilateral, seasonally exacerbated, allergic inflammation of the ocular surface, involving bulbar and ? or tarsal conjunctiva and cornea. The ocular response analyzer (ORA) measures corneal biomechanical properties in vivo by monitoring and analyzing the corneal behavior when its structure is submitted to a force induced by an air jet. This study was designed to examine corneal biomechanical properties and intraocular pressure in patients with VKC, and to compare with control eyes.

Methods

ORA measurements were performed on the both eyes of 26 patients with VKC (group I) and 14 healthy children who served as the control group (group II). Corneal hysteresis (CH), corneal resistance factor (CRF) and intraocular pressure [Goldmann correlated (IOPg) and corneal compensated (IOPcc)] were recorded with ORA.

Results

Mean age of patients with VKC and control groups were 11.3?±?5.8 and 10.6?±?1.9 years for groups I and II respectively. Mean (± SD) of the CH and CRF readings were 10.1?±?1.6 versus 10.5 ±1.6 (p?>?0.05) and 9.5?±?1.7 versus 10.8?±?1.7 mmHg (p?<?0.05), in groups I and II respectively. Mean (± SD) of the IOPg and IOPcc recordings were 13.3 ±3.4 versus 16.6 ±3.6 mmHg (p?<?0.05) and 14.3?±?3.4 versus 16.9?±?3.7 mmHg (p?>?0.05) in groups I and II respectively. Statistical analysis revealed significant differences for CRF and IOPg between the study groups.

Conclusion

The mean CRF and IOPg values of patients with VKC were lower than those of controls. According to the results of our study, one can conclude that corneal biomechanical property, CRF, could be different in VKC patients compared to normals.     

Associations with retinal vascular occlusions in a diverse,urban population

Purpose: Retinal vascular occlusions can lead to sudden and permanent visual impairment or blindness. Few epidemiological studies on retinal vascular occlusions have been conducted, especially on diverse populations.

Methods: This is a retrospective case-control study of all incident retinal vascular occlusions occurring during a three and one-half year study period at Montefiore Medical Center, capturing all potential cases by diagnosis codes. Patients with retinal venous occlusions (RVO) and retinal arterial occlusions (RAO) were analyzed separately and compared to age-matched control groups.

Results: All potential charts (n = 700) were reviewed, confirming 214 RVO and 35 RAO incident cases. In multivariable analyses, RVO was associated with type 2 diabetes mellitus (OR 2.41, p < 0.001), history of cerebrovascular accident (OR 2.14, p = 0.011), hypertension (OR 1.83, p = 0.004), glaucoma (OR 6.91, p < 0.001), black race (OR 3.72, p < 0.001), and male gender (OR 2.19 p < 0.001). RAO was significantly associated with current and former smoking combined (OR 8.95, p = 0.021) and male gender (OR 2.56, p = 0.038).

Conclusion: Cardiovascular risk factors and glaucoma are reaffirmed as significant predictors of retinal vascular occlusions in a diverse patient population. Retinal vascular occlusions are more common in certain races and ethnicities, and further study into this may help identify high-risk individuals based on demographics.     

Internal limiting membrane dragging and peeling: a modified technique for macular holes closure surgery

AIM: To introduce a modified technique of internal limiting membrane (ILM) centripetal dragging and peeling to treat idiopathic macular hole (IMH) and to observe the ILM-retina adhesive forces. METHODS: Twenty-six consecutive patients with stage 3 to 4 IMH and followed up at least six months were enrolled. All patients underwent complete par plana vitrectomy, ILM dragging and peeling, fluid and gas exchange, 15% C3F8 tamponade and 2-week prone position. The best corrected visual acuity, macular hole evaluation by optical coherence tomography, and complications were evaluated. RESULTS: The mean diameter of IMH was 524±148 μm (range: 201-683 μm), with 21 cases (80.8%) greater than 400 μm. ILM dragging and peeling were successfully performed in all cases. Most of the ILM-retina adhesive forces are severe (42.3%, 11/26), followed by mild (38.5%, 10/26), and moderate (19.2%, 5/26). The mean follow-up duration was 21.2±6.1mo. The IMH was closed in 25 (96.3%) eyes. Visual acuity (logMAR) improved significantly from 1.2±0.6 preoperatively to 0.7±0.5 postoperatively (P<0.001). CONCLUSION: Preexisting ILM-retina adhesive force is found in IMH patients. With assistance of this force, this modified technique may help to release the IMH edges and improve the closure rate of large IMH.     

Ocular response analyser measurements and central corneal thickness in ocular rosacea patients

Rosacea is a chronic cutaneous disorder which is known to cause inflammation and increased proteolytic activity on the ocular surface that might lead to corneal biomechanical alterations. The aim of this study is to evaluate the corneal biomechanical properties of ocular rosacea patients and compare the measurements with healthy individuals as measured with Reichert ocular response analyser (ORA). Besides full eye examination [best corrected visual acuity (BCVA), intraocular pressure (IOP) measured with Goldmann applanation tonometry (IOP-G)], central corneal thickness (CCT), and ORA [corneal hysteresis (CH), corneal resistance factor (CRF), corneal compensated IOP (IOPcc), Goldmann correlated IOP (IOPg)] measurements of 30 eyes of 15 ocular rosacea patients (study group) and 30 eyes of 15 healthy individuals (control group) were performed. For comparisons paired t test was used. Mean age of study group was 45.26 ± 11.65 (range 25 and 63) and control group was 45.00 ± 8.91 (range 26 and 58) years (p = 0.865). No significant difference in BCVA, CCT, IOP-G, IOPcc was detected among groups. However, IOPg, CH, and CRF in the study group were significantly lower than in the control group (p = 0.013, p = 0.013, p = 0.009, respectively). IOPg, CH, and CRF parameters of ocular rosacea patients were significantly lower than normal individuals. These differences and their probable clinical reflections that might effect making decisions in conditions such as glaucoma should be investigated in larger number of patients.     

LASIK术后角膜生物力学变化与眼压测量值的相关性

目的 观察LASIK术后角膜生物力学参数和眼压测量值的变化及角膜生物力学变化与眼压的相关性。设计 前瞻性病例系列。研究对象 哈尔滨医科大学附属第一医院2014年1-12月LASIK手术患者81例（162眼）。方法 应用非接触眼压计（non-contact tonometer,NCT）分别在术前及术后3个月测量眼压。同时应用眼反应分析仪（ocular response analyzer,ORA）测量角膜滞后量（corneal hysteresis,CH）、角膜阻力因子（corneal resistance factor, CRF）、模拟Goldmann 眼压（Goldmann intraocular pressure,IOPg）和角膜补偿眼压（corneal-compensated intraocular pressure,IOPcc）。比较手术前后各参数的变化并分析术后角膜生物力学参数变化与眼压测量值的相关性。 主要指标 手术前后NCT、IOPcc、IOPg、CH、CRF。 结果 LASIK术后3个月CH、CRF、IOPcc、IOPg、NCT测量值与术前比较均显著降低,术后IOPcc与IOPg和NCT之间比较差异均有统计学意义（P<0.05）;△CH、△CRF与△IOPcc、△IOPcc- IOPg和△IOPcc-△NCT均成负相关,△CH、△CRF与△IOPg和△NCT均成正相关（P<0.05）;CH和CRF的减少量与眼压测量值下降具有相关性（P<0.05）。结论 LASIK术后角膜生物力学参数和眼压测量值均较术前显著降低,眼压测量值下降与CH和CRF的减少量具有相关性,说明眼压下降的程度可能受角膜生物力学特性的影响。     

Investigation of corneal biomechanics at moderate to high refractive errors

Purpose

Corneal hysteresis (CH) and corneal resistance factor (CRF) are corneal biomechanical parameters which were measured by ocular response analyzer (ORA). Aim of this study was to define the CH and CRF in high myopic and hyperopic patients and compare the results with emmetropic control group.

Methods

A total of 193 eyes of 100 healthy volunteers were included. Study groups were high myopic patients (n = 27) with spherical refractive errors (SRE) of greater than ?5.00D, high hyperopic patients (n = 20) with SRE of greater than +3.00D and controls (n = 53) with SRE between ± 1.00D. All subjects underwent IOP and corneal biomechanical evaluation with the ORA. Also Goldmann applanation tonometry (GAT), central corneal thickness (CCT), corneal curvature and axial length measurements were taken.

Results

Mean age of groups was 30.7 ± 6.9, 29.1 ± 7.7, 28.9 ± 5.6 years (p > 0.05). Among study groups except CRF and CCT, all parameters were significantly different between study groups. CH was lowest in the high myopic group and highest in the high hyperopia. In all groups, there were significant correlations between CH and CRF, CCT, SRE, SE (spherical equivalent), AL (axial length) and between CRF and CCT. GAT and IOPg (Goldmann-correlated intraocular pressure) measurements were significantly correlated with CCT (p < 0.05). One of the major findings was as the CH approaches 11.2 mmHg, IOPcc (corneal-compensated intraocular pressure) and IOPg get close to each other.

Conclusions

The results revealed that CRF is not affected by refractive errors and IOPcc is not affected by any other ocular parameter. The difference between IOPcc and IOPg was greatest in myopic group, and IOP (intraocular pressure) measurement in these patients deserves high suspicion.

     

青年女性生理周期期间角膜生物力学性能和眼压的节律性变化

目的探讨中国青年女性生理周期期间角膜生物力学性能和眼压的节律性变化以及两者之间的关系。方法前瞻性研究。41例健康青年女性分别在月经周期初期、排卵期和月经周期末期用眼反应分析仪（ORA）对角膜补偿眼压（IOPcc）、可重复模拟Goldmman眼压（IOPg）、角膜滞后量（CH）和角膜阻力因子（CRF）进行测量。采用Pentacam对CCT进行测量。采用重复测量方差分析法分析测量参数在不同时间点的变化以及Pearson相关进行相关性分析。结果在女性生理周期的不同阶段,CCT、CH和CRF存在波动,但差异无统计学意义,在月经周期末期IOPcc和IOPg均较初期显著下降（P<0.01）。△IOPg与△CRF呈低度正相关（r=0.356,P<0.05）,与△CH呈低度负相关（r=-0.336,P<0.05）,△IOPcc则与△CH呈中度负相关（r=-0.702,P<0.01）,与△CRF不相关（r=-0.069,P>0.05）。△CRF、△CH、△IOPg和△IOPcc均与△CCT无明显相关性（│r│均<0.3,P均>0.05）。结论在女性生理周期期间,角膜生物力学性能无明显变化但眼压在月经周期末期发生了显著下降。IOPg的变化与CH、CRF低度相关,而IOPcc则与CH中度相关,与CRF不相关。角膜生物力学性能可能是眼压的影响因素之一。     

Influence of corneal astigmatism, corneal curvature and meridional differences on corneal hysteresis and corneal resistance factor

Background: This study investigated the influence of corneal astigmatism, corneal curvature and meridional differences on corneal hysteresis (CH) and the corneal resistance factor (CRF) in a group of normal Chinese persons. Methods: Ninety‐five participants were recruited and data from the eye with higher corneal astigmatism were analysed. The anterior corneal curvature was measured by corneal topography. The Goldmann‐correlated intraocular pressure (IOPg), corneal‐compensated intraocular pressure (IOPcc), CH and CRF at different meridians (default horizontal position, 10°, 20° and 30° along the superotemporal and inferonasal meridians) were obtained from an ocular response analyser. The corneal powers at these specific meridians also were calculated. Results: At the default position, the IOPg and CRF had weak correlations with corneal astigmatism, while the IOPcc and CH were not significantly correlated with corneal astigmatism. Both the IOPg and IOPcc were measured significantly higher at the default position. The CH and CRF were lower at the default position but the difference in the CRF from obliquity could not reach statistical significance. The CH was not significantly correlated with the corneal power at all meridians. The CRF correlated with the corneal power only at 30° superotemporal. Conclusion: Corneal astigmatism and head tilt did not have much effect on the measurement of CH and the CRF, both of which were lowest along the horizontal meridian. Clinically, the difference was small. The influence of corneal power on CH and the CRF was minimal.     

Relationship Between Corneal Hysteresis and Corneal Resistance Factor with Other Ocular Parameters

Abstract

Purpose: To evaluate the relationship between corneal hysteresis (CH) and corneal resistance factor (CRF) with age, central corneal thickness (CCT), corneal curvature (KM), corneal volume (CV), and refractive error in naïve eyes. Methods: 105 healthy subjects (58 male and 47 female) were included in this study. The ages ranged from 19 to 82 years (mean 43.1?±?15.4 years) and refraction between ?11?D and +6?D (mean ?0.79?±?2.95?D). CH and CRF obtained with the Ocular Response Analyzer (ORA) were correlated with age, refractive error, Goldmann Applanation Tonometry (GAT), and with CCT, KM, CV obtained with the Pentacam, and with Corneal-Compensated Intraocular Pressure (IOPcc) and Goldmann-correlated intraocular pressure measurement (IOPg) obtained with ORA. A multivariable mixed effect model was used to evaluate associations among these parameters. Results: CH ranged from 6.9 to 14.6?mmHg (mean 10.26?±?1.49?mmHg); CRF ranged from 5.8 to 17?mmHg (mean 10.38?±?1.64?mmHg). Multivariate analysis showed a statistically significant correlation between CH with CCT (p?<?0.001), and KM (p?<?0.001), and between CRF with CCT (p?<?0.001) and GAT (p?<?0.001). Conclusions: Our findings support the hypothesis that CH and CRF are related to the corneal shape and thickness, and show a decrease of CH with age.     

角膜补偿眼压与前房穿刺测量眼内压的比较

目的 比较角膜补偿眼压(IOPcc)与前房穿刺测量眼压(direct intracameral IOP,IOPintra),探讨角膜生物特性对眼压测量的影响.方法 双肓前瞻性研究.拟行超声乳化手术患者73例(73只眼),随机选择1只眼.超声测厚仪测量中央角膜厚度(CCT),ORA测量IOPcc和角膜生物属性:角膜滞后性(cornealhysteresis,CH).角膜阻力因子(corneal resistance factor,CRF).应用IOD眼压测量装置行前房穿刺测量IOPintra.结果 IOPintra为(15.48±4.64)mmHg,IOPcc为(16.63±3.68)mmHg;IOPcc高出IOPintra(1.15±4.12)mmHg(P=0.019);IOPcc和IOPintra与CH、CRF相关,IOPcc,IOPintra及两者的差异与CCT不相关;IOPcc与IOPintra的差异与cH相关(r=-0.283 P=0.015).结论 IOPcc读数比IOPintra高1.15mmHg,其差异受CH影响.角膜生物属性对眼压测量的影响需慎重考虑.