Comparison of dynamic contour tonometry and Goldmann applanation tonometry in relation to central corneal thickness in primary congenital glaucoma

Background

To compare intraocular pressure (IOP) measurements obtained with dynamic contour tonometer (DCT) and Goldmann applanation tonometer (GAT), and to investigate their relationship to central corneal thickness (CCT) in primary congenital glaucoma (PCG) eyes.

Methods

Thirty-one eyes of 31 PCG patients (25.7?±?7.2 years old) were examined. PCG was defined as elevated IOP, enlarged corneal diameter (buphthalmos), Haab’s striae and abnormal findings at gonioscopy. The mean of three measurements of GAT, DCT (quality scores 1 and 2), and CCT were obtained and assessed for agreement by means of Bland–Altman plot and for Spearman correlation test.

Results

Mean CCT was 534?±?72.3 μm (range: 430 to 610 μm). Mean IOP measurements were 15.1?±?4.2 mmHg (range: 5.5 to 22.7 mmHg) for DCT and 14.5?±?5.6 mmHg (range: 7.0 to 34.0 mmHg) for GAT (P?=?0.244). Spearman correlation tests showed that IOP difference (DCT ? GAT) was not correlated with CCT (r ²?=?0.023, P?=?0.417). IOP measurements by DCT were weakly but statistically correlated with those obtained with GAT (r²?=?0.213, P?=?0.0089). Bland–Altman analysis revealed poor agreement between DCT and GAT readings, considering the 95 % confidence intervals of ±10.45 mmHg.

Conclusions

The differences between DCT and GAT readings were not influenced by CCT in this series of patients. Considering the weak correlation and the poor agreement observed between GAT and DCT measurements and that they both may be affected by corneal biomechanical changes, these methods should not be used interchangeably, and may possibly give no meaningful IOP values in PCG patients.     

A comparison between Goldmann applanation tonometry and dynamic contour tonometry after photorefractive keratectomy

Background

The intraocular pressure (IOP) could be measured by both Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT). Although these two methods have been discussed widely after laser-assisted sub-epithelial keratectomy (LASIK), there is little data in the cases undergoing photorefractive keratectomy (PRK). We aimed to compare the changes of IOP measurements obtained by GAT and DCT after PRK for myopia/myopic astigmatism.

Methods

This prospective study enrolled 77 candidates (154 eyes) for PRK to correct myopia or myopic astigmatism and 30 matched patients (30 eyes) with myopia or myopic astigmatism who served as controls. Changes of the IOP measurements (ΔIOP) obtained by GAT and DCT before and at 6 months after PRK in the operated eyes, and at baseline and 6 months later in the controls, were documented. Changes of the central corneal thickness (ΔCCT) were determined in the same fashion.

Results

The mean IOP readings obtained by DCT were comparable before and at 6 months after procedure (18.34 ± 3.03 mmHg and 17.87 ± 2.61 mmHg respectively, p?=?0.41); whereas the mean IOP reading obtained by GAT decreased significantly 6 months postoperatively (17.92 ± 3.63 mmHg and 16.25 ± 2.66 mmHg, p?<?0.001). A significant correlation was present between the ΔIOP obtained by GAT and ΔCCT (r?=?0.61, p?<?0.001). Similar correlation was not significant between the DCT-obtained ΔIOP and the ΔCCT (r?=?0.07, p?=?0.44). The mean ΔIOP obtained by GAT was significantly higher in the operated eyes than in the controls (?1.54?±?1.45 vs 0.07?±?0.44 mmHg, p?=?0.02). The mean DCT-obtained ΔIOP was just marginally insignificant between the operated and nonoperated eyes (?0.63?±?0.59 vs 0.02?±?0.38 mmHg respectively; p?=?0.09).

Conclusions

The authors recommend DCT after PRK in the cases with myopia or myopic astigmatism     

Vergleich des iCare-Tonometers mit dem Goldmann-Tonometer in Malawi

Background

The risk for glaucoma is 4?C5 times higher in patients from sub-Saharan Africa. Thus, especially in developing countries an easy and effective method for assessing the intraocular pressure (IOP) is needed.

Methodology

In this hospital-based survey 150 eyes were divided into 3 groups concerning the IOP (group I <?16?mmHg, group II 16?C23?mmHg and group III >?23?mmHg) and underwent examination with ultrasound pachymetry followed by iCare tonometry (ICT) and Goldmann applanation tonometry (GAT). Agreement of the measurements by two tonometers was assessed with the Bland-Altman method and the influence of the central corneal thickness (CCT) on the ICT measurements was determined.

Results

The mean difference between the IOD measured with GAT and ICT was 0.84?±?2.63?mmHg. The differences were similar in all three groups (0.77?C0.97?mmHg), however, the standard deviation in group III (4.04?mmHg) was greater than in groups I (1.98?mmHg) and II (1.79?mmHg). The mean CCT was 513.51?±?36.22???m.

Conclusions

The agreement of measurements by GAT and ICT was good for lower IOP values but less accurate in patients with higher IOP values (group III). A dependency of the CCT on the ICT measurements was observed. In comparison to other countries the lowest CCTs were found in Malawian patients.     

Evaluierung der dynamischen Konturtonometrie bei Keratokonus

Purpose

The gold standard for measuring intraocular pressure (IOP) until now has been Goldmann applanation tonometry (GAT), which depends on the central corneal thickness (CCT) and curvature. In patients with keratoconus who have an abnormal corneal geometry and thickness, measurement of pressure with GAT is often difficult and not very reproducible. We compared the impact of the central corneal thickness (CCT) on the IOP measured with dynamic contour tonometry (DCT), a digital method which is adapted to the corneal geometry, and GAT in patients with keratoconus.

Methods

IOP was measured in 54 patients (38 men and 16 women, mean age of 36±9.9 years) with GAT and DCT in randomized order. All patients had a keratoconus which was assured by topography. In addition central corneal thickness (CCT) was measured with the Pentacam. For statistical analysis the Pearson correlation was calculated and a Bland-Altman diagram plotted.

Results

Mean corneal thickness was 486.2±45.5 μm. DCT measured the IOP at a mean value of 14.9±2.6 mmHg and GAT at 13.3±2.9 mmHg. With a mean difference of 1.6±2.4 mmHg DCT measured significantly higher than GAT (p≤0.05) Neither IOP measurements with GAT (r=?0.03; p>0.05) nor those with DCT (r=0.08; p>0.05) showed a significant correlation to central corneal thickness.

Conclusion

The example of keratoconus confirms that IOP measured by GAT is lower than if measured by DCT. Because both methods are independent of the CCT they are equally acceptable for IOP follow-up in eyes with keratoconus, which may result in progressive corneal thinning in the long term.     

Hornhautdickenunabhängige Methoden der Messung des Augeninnendrucks

Introduction

Goldmann applanation tonometry (GAT) has been the gold standard for measuring intraocular pressure (IOP) for about 50 years. However, it depends on central corneal thickness (CCT) and is, therefore, prone to being incorrect. Dynamic contour tonometry (DCT) has recently been introduced to measure IOP independently of CCT; however, DCT is costly and difficult. IOP measurement using the ocular response analyzer (ORA) offers noncontact tonometry with declaration of the corneal-compensated IOP (IOPcc), which takes corneal hysteresis (CH) into account and is supposed to be independent of CCT.

Patients and methods

Using the ORA instrument, IOPcc was determined in 192 glaucoma eyes and 59 nonglaucoma eyes. Subsequently, measurement by DCT and GAT was performed. IOP measurements were compared and analyzed with respect to CCT and CH.

Results

Average values were as follows: IOPcc, 18.38±6.3 mmHg; GAT, 14.69±4.5 mmHg; DCT, 15.17±3.9 mmHg; CH, 9.96±2.5 mmHg; CCT, 552±57 μm. Neither CCT nor CH differed between the two groups. There was a positive correlation between GAT and CCT that did not exist for IOPcc and DCT values. However, IOPcc and DCT differed significantly in Bland–Altman analysis (p<0.01). Furthermore, these two IOP values differed significantly with respect to CH and the level of IOP.

Conclusion

Because IOPcc is not a primarily measured variable but also takes CH into account, a direct comparison of DCT and IOPcc values is not acceptable, and a simple correction factor may not be valid.     

Age-dependency of ocular parameters: a cross sectional study of young and elderly healthy subjects

Purpose

To investigate the effect of aging on ocular parameters, including intraocular pressure (IOP), measured with different tonometry methods in healthy young (HY) and healthy elderly (HE) subjects and to study the effect of corneal parameters on tonometry methods.

Methods

In this prospective, cross-sectional study, fifty eyes of 50 HY subjects (28 females, 22–31 years of age) and 43 eyes of 43 HE subjects (22 females, 64–79) were included. IOP was measured with four tonometry methods in a standardized order: ocular response analyser (ORA), dynamic contour tonometry (DCT), applanation resonance tonometry (ART) and Goldmann applanation tonometry (GAT). Other measurements included axial length (AL), central corneal thickness (CCT), corneal curvature (CC), anterior chamber volume (ACV), corneal hysteresis (CH) and corneal resistance factor (CRF).

Results

The mean IOP (HY/HE; mmHg?±?standard deviation (SD)) was 12.2?±?2.2/14.1?±?3.5 with GAT. IOP was significantly higher (difference?±?standard error) in HE compared to HY measured with an ORA (+3.1 mmHg?±?0.6), GAT (+1.9?±?0.6) and DCT (+1.6?±?0.6). No significant difference was found in IOP measured with ART. CH and ACV were significantly lower in HE compared to HY. There was no difference between the groups in CCT, CC, AL or CRF. No tonometry method was dependant on CCT or CC.

Conclusions

IOP measured with an ORA and via DCT and GAT was higher in HE compared to HY Swedish subjects, while IOP measured with ART did not differ between the groups. In these homogeneous groups, tonometry methods were independent of CCT and CC.

     

Can we trust intraocular pressure measurements in eyes with intracameral air?

Purpose

To evaluate the effect of intracameral air on intraocular pressure (IOP) measurements using Goldmann applanation tonometry (GAT) and applanation resonance tonometry (ART) in an in-vitro porcine eye model.

Methods

IOP was measured on thirteen freshly enucleated eyes at three reference pressures: 20, 30, and 40 mmHg. Six measurements/method were performed in a standardized order with GAT and ART respectively. Air was injected intracamerally in the same manner as during Descemet’s stripping endothelial keratoplasty (DSEK) and Descemet’s membrane endothelial keratoplasty (DMEK), and the measurements were repeated.

Results

Measured IOP increased significantly for both tonometry methods after air injection: 0.7?±?2.1 mmHg for GAT and 10.6?±?4.9 mmHg for ART. This difference was significant at each reference pressure for ART but not for GAT.

Conclusions

Although slightly affected, this study suggests that we can trust GAT IOP-measurements in eyes with intracameral air, such as after DSEK/DMEK operations. Ultrasound-based methods such as ART should not be used.     

Unterschiede in den Messergebnissen nach Goldmann-Applanationstonometrie mit und ohne Fluoreszein

Background

Goldmann applanation tonometry (GAT) is still the gold standard for measuring the intraocular pressure (IOP). Usually fluorescein eye drops are used additional to topical anesthesia to gain the best visualization results. The present study evaluated the differences in the results of GAT with and without fluorescein.

Methods

A total of 400 eyes of 200 patients without known glaucoma were enrolled in this study and randomized to two groups: group A (first measurement without, second measurement with fluorescein) and group B (first measurement with fluorescein, second without). All measurements were performed by the same examiner with the same slit lamp. Results were analyzed by Bland-Altman plots and Spearman’s correlation test.

Results

The examined groups showed no significant differences regarding patient age, astigmatism or reason for consulting. In both groups performing GAT without the application of fluorescein led to significantly lower measurement results. The differences were 1.5?±?1.7 mmHg SD in group A, 1.2?±?1.6 mmHg SD in group B and 1.4?±?1.65 mmHg SD for all eyes. The intraocular pressure (IOP) and the differences between the groups were independent of patient age, astigmatism, reason of consulting or IOP level. Both groups showed outliers up to 10 mmHg difference because of corneal edema.

Conclusions

Measurements from GAT without fluorescein differed significantly from measurements with fluorescein, independently of patient age, astigmatism, reason for consulting or IOP level. The mean difference of 1.4 mmHg may seem negligible in daily routine but can lead to serious consequences in borderline cases.     

Einfluss der Hornhautdicke nach posteriorer lamell?rer Keratoplastik (DSAEK) auf die Messung des Augeninnendrucks

Background

The aim of this study was to evaluate the effect of increased corneal thickness after Descemet??s stripping automated endothelial keratoplasty (DSAEK) on intraocular pressure (IOP) measured by four different techniques.

Methods

In this study 30 eyes from 30 patients with successful DSAEK treatment (group 1) and 30 eyes of 30 healthy subjects (group 2) were enrolled. The IOP was measured with iCare, IOPen, Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT) techniques. Central corneal thickness (CCT) was measured by ultrasonic pachymetry. These data were used for statistical analysis.

Results

The mean IOP measured by GAT, DCT, iCare and IOPen was 13.2, 16.1, 12.5 and 14.2?mmHg in group 1 and 13.4, 14.4, 14.4 and 13.3?mmHg in group 2, respectively. Correlations between IOP and CCT were not statistically significant in either group.

Conclusion

The results of IOP measurements by the iCare, IOPen, GAT and DCT techniques seem to be unrelated to artificially thickened corneas after DSAEK. In spite of partially good correlation between the four techniques a direct exchange of the devices is not recommended on account of the wide dispersion of values.     

Effect of central corneal thickness on intraocular pressure and comparison of Topcon CT‐80 non‐contact tonometry with Goldmann applanation tonometry

Background

To compare intraocular pressure (IOP) measurements obtained with the Topcon CT‐80 non‐contact tonometer (NCT) and Goldmann applanation tonometer (GAT), in different ranges of IOP in normal and glaucoma subjects, and to assess the influence of central corneal thickness (CCT) on the IOP measurements in Asian Indian eyes.

Methods

Four hundred and two eyes of 402 subjects (193 newly diagnosed primary open angle glaucoma [POAG] and 209 normal) were enrolled for this prospective study. For each eye, IOP was measured with GAT by a glaucoma specialist and NCT by a trained optometrist. The IOP values were compared among the tonometers in the three different IOP ranges (≤ 12 mmHg, 13–20 mmHg and ≥ 21 mmHg) using Bland–Altman graphs. Correlation between GAT and NCT was assessed by Pearson correlation co‐efficient. CCT was measured with ultrasound pachymetry and its correlation with GAT and NCT was analysed using linear regression analysis.

Results

The mean paired difference of IOP between NCT and GAT was 1.556 ± 2.69 mmHg (r = 0.26, p = 0.006) at IOP range of ≤ 12 mmHg, ?1.665 ± 2.6 mmHg (r = 0.51, p < 0.0001) in IOP range of 13–20 mmHg and ?2.202 ± 3.44 mmHg (r = 0.82, p < 0.0001) in the IOP range of ≥ 21 mmHg. Linear regression analysis showed a mean IOP variation of 0.27 mmHg per 10 μm change in CCT for NCT (p < 0.0001) and IOP change of 0.19 mmHg per 10 μm change in CCT for GAT (p = 0.01).

Conclusion

In this study of normotensive and POAG subjects, the Topcon CT‐80 NCT showed an overestimation of IOP at the lower range and underestimation of IOP in normal and higher ranges of IOP. Clinicians should keep in mind that CCT influences IOP measurement with both types of tonometer and that the IOP readings obtained with these tonometers are not interchangeable.

     

Corneal biomechanics predict the outcome of selective laser trabeculoplasty in medically uncontrolled glaucoma

Purpose

To evaluate the predictive value of clinical parameters, including biomechanical properties on the outcome of selective laser trabeculoplasty (SLT) in medically uncontrolled open angle glaucoma (OAG).

Methods

Sixty-eight eyes from 68 patients with OAG and IOP insufficiently regulated by topical medications were enrolled. Patients’ follow-up occurred 6 and 12 months after the procedure. The recorded parameters intraocular pressure (IOP), angle characteristics, central corneal thickness (CCT) and biomechanical properties of the eyes, including corneal hysteresis CH and corneal resistance factor CRF measured with the Ocular Responses Analyzer (ORA, Reichert Ophthalmic Instruments) were tested on their predictive value of SLT-induced IOP lowering effect using correlation analyses and regression models.

Results

Mean IOP reduction 12 months after SLT was 4.2?±?5.7 mmHg (23.2 %, from baseline 18.1?±?5.2 mmHg). The preoperative IOP correlated significantly with IOP reduction (maximum Spearman’s correlation r?=?0.75, p?<?0.001). In linear regression analysis, the corneal biomechanical properties (CH and CRF) together with the baseline IOP revealed good modelling for the IOP lowering effect of SLT (R²?=?0.64, respectively).

Conclusions

In addition to the baseline IOP biomechanical properties (CH and CRF) are significant predictors of SLT induced IOP lowering effect in medically uncontrolled OAG.     

Hornhautdickenabhängige Korrekturfaktoren bei der Goldmann-Applanationstonometrie

Background

For many years researchers have discussed which corneal parameters can influence the measurement of intraocular pressure (IOP). As a substantial parameter, the central corneal thickness (CCT) is assumed; however, different measuring methods – including Goldmann applanation tonometry (GAT), dynamic contour tonometry (DCT), and corneal compensated pressure measured with the ocular response analyzer (IOPcc) – may lead to a completely different dependence on corneal thickness.

Method

In a study approved by the ethics commission, the anterior chamber of 92 eyes of cataract patients and 85 eyes of glaucoma patients with very different CCT measurements was cannulized before surgery (cataract operation or trabeculectomy), and the IOP values were measured simultaneously with a pressure absorber and with GAT (Perkins tonometer) at different pressure values.

Results

The individual measurements exhibited an extraordinarily wide dispersion. In both groups, weak correlations of the difference between GAT and IOP values with the CCT were found (correction factors of 0.95 mmHg/100 µm CCT at pressure level 20 mmHg, 1.2 mmHg/100 µm CCT at pressure level 30 mmHg, and 1.7 mmHg/100 µm CCT at pressure level 40 mmHg).

Conclusions

Measurement of CCT is valuable for prognostic assessment of glaucoma, but not for correction factors for corneal thickness.     

Changes of extracellular matrix of the cornea in diabetes mellitus

Purpose

Differences in corneal viscoelasticity due to diabetes have been reported to have a protective effect on the progression of glaucoma and the development and progression of keratoconus. Due to longterm changes of tissue in diabetes mellitus, biomechanical changes of the cornea because of glycation and modified extracellular matrix may be detectable. The purpose of the study was to determine whether there is a difference in corneal biomechanical properties, characterized by corneal hysteresis (CH) and central corneal thickness (CCT), between diabetic and normal subjects, and relate these to the duration of diabetes.

Method

In a cross sectional study, a group of 484 eyes including 99 eyes of diabetic individuals was evaluated. CH as measured with the Ocular Response Analyzer, CCT (Orbscan II), Goldmann applanation tonometry (GAT) and slit-lamp examination were obtained from each patient. Linear mixed models were applied for statistical evaluation.

Results

CH showed a significant decrease with age (-0.036 mmHg/year, p?<?0.01) while CCT increased significantly (+0.7 µm/year, p?<?0.001). CH was significantly higher in diabetic eyes with an average difference of +0.55 mmHg (after correcting for age, IOP and CCT). This was not related to the duration of diabetes (mean 12.6?±?9.0y, p?=?0.522). CCT did not differ with regard to diabetes. Intraclass correlation coefficients were 81% and 50% for CCT and CH respectively.

Conclusion

CH is assumed to be an indicator for acquired changes of tissue such as diabetes-mediated. CCT is a more characteristic parameter for the individual patient. CH may provide more information about changes of the extracellular matrix in diabetes, and therefore offer a new monitoring parameter.     

Assessment of intraocular pressure measured by Reichert Ocular Response Analyzer, Goldmann Applanation Tonometry, and Dynamic Contour Tonometry in healthy individuals

AIM: To investigate the accuracy of intraocular pressure (IOP) as measured by a Reichert Ocular Response Analyzer (ORA), as well as the relationship between central corneal thickness (CCT) and IOP as measured by ORA, Goldmann applanation tonometry (GAT), and dynamic contour tonometry (DCT). METHODS: A total of 158 healthy individuals (296 eyes) were chosen randomly for measurement of IOP. After CCT was measured using A-ultrasound (A-US), IOP was measured by ORA, GAT, and DCT devices in a randomized order. The IOP values acquired using each of the three tonometries were compared, and the relationship between CCT and IOP values were analyzed separately. Two IOP values, Goldmann-correlated IOP value (IOPg) and corneal-compensated intraocular pressure (IOPcc), were got using ORA. Three groups were defined according to CCT: 1) thin cornea (CCT<520μm); 2) normal-thickness cornea (CCT: 520–580μm); and 3) thick cornea (CCT>580μm) groups. RESULTS: In normal subjects, IOP measurements were 14.95±2.99mmHg with ORA (IOPg), 15.21±2.77mmHg with ORA (IOPcc), 15.22±2.77mmHg with GAT, and 15.49±2.56mmHg with DCT. Mean differences were 0.01±2.29mmHg between IOPcc and GAT (P>0.05) and 0.28±2.20mmHg between IOPcc and DCT (P>0.05). There was a greater correlation between IOPcc and DCT (r=0.946, P=0.000) than that between IOPcc and GAT (r=0.845, P=0.000). DCT had a significant correlation with GAT (r=0.854, P=0.000). GAT was moderately correlated with CCT (r=0.296, P<0.001), while IOPcc showed a weak but significant correlation with CCT (r=?0.155, P=0.007). There was a strong negative correlation between CCT and the difference between IOPcc and GAT(r=-0.803,P=0.000), with every 10μm increase in CCT resulting in an increase in this difference of 0.35mmHg. The thick cornea group (CCT>580μm) showed the least significant correlation between IOPcc and GAT (r=0.859, P=0.000); while the thin cornea group (CCT＜520μm) had the most significant correlation between IOPcc and GAT (r=0.926, P=0.000). The correlated differences between IOPcc and DCT were not significant in any of the three groups (P>0.05). CONCLUSION: Measurement of IOP by ORA has high repeatability and is largely consistent with GAT measurements. Moreover, the ORA measurements are affected only to a small extent by CCT, and are likely to be much closer to the real IOP value than GAT.     

Switching efficacy on intraocular pressure from latanoprost to bimatoprost in eyes with open angle glaucoma: implication to the changes of central corneal thickness

Purpose

Intraocular pressure (IOP)-lowering effects of 0.03 % bimatoprost in eyes with open angle glaucoma (OAG) was compared with that of 0.005 % latanoprost.

Methods

Thirty-one patients with OAG who had received three kinds of ocular hypotensive agents (latanoprost, beta-blocker, and topical carbonic anhydrase inhibitor) were included in this study. In these patients, bimatoprost was administered for 8 weeks after switching from latanoprost. The IOP was measured with a goldmann applanation tonometer (GAT) at the baseline, and Weeks 2, 4 and 8 after switching the treatment. The IOP at the baseline and at the end of treatment period was measured at 10:00, 12:00, and 16:00. The central corneal thickness (CCT) was measured at each visit using an ultrasonic pachymeter.

Results

At the baseline, the mean IOP was 18.8 ± 1.4 mmHg, and the CCT was 530.7 ± 29.5 μm. At Week 8 after switching treatment, bimatoprost significantly reduced the IOP by 2.0 ± 1.6 mmHg from the baseline (p < 0.001). The CCT tended to be reduced (p = 0.009; Repeated ANOVA) and Bonferroni test indicated a statistically significant decrease of the CCT at Week 8 in comparison with that at the baseline (p = 0.013).

Conclusions

Bimatoprost has an IOP-lowering effect superior to that of latanoprost in glaucoma patients after switching from latanoprost. The use of bimatoprost can decrease the CCT for a relatively short period in a linear regression fashion.     

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.     

Comparative measurement of intraocular pressure by Icare tonometry and Airpuff tonometry in healthy subjects and patients wearing therapeutic soft contact lenses

Background

The aim of the present study was to compare the measurement of intraocular pressure (IOP) through a therapeutic soft contact lens with the “native” measurement. We additionally investigate whether a rebound tonometer (RT) or non-contact tonometer (NCT) is more suitable to measure IOP through a bandage contact lens.

Methods

The IOP was determined using each of the two methods, three times successively with (lens measurement) and without (native measurement) a soft contact lens. The Icare tonometer (Icare® TA01i, Icare Finland Oy, 23 subjects) and the Airpuff tonometer (Nidek NT 53OP, Nidek CO., LTD, Hiroishi Gamagori, Aichi, Japan, 16 subjects) were used. We compared the mean values (validity parameter) and standard deviation (precision parameter) of the three individual measurements in each case using the paired t-test. In addition, we conducted a power analysis to estimate the maximum error in the measurement caused by the contact lens (power level set to 0.8).

Results

With the Airpuff tonometer we detected no statistically significant between the lens and the native measurement (15.6?±?2.6 vs. 15.3?±?2.6 mmHg; p?=?0.42). The power analysis revealed that the maximum error caused by the contact lens was 1.2 mmHg. The Icare tonometry, however, trended toward higher values in the contact lens measurements (17.5?±?4.3 vs. 16.4?±?3.5 mmHg in the native measurements; p?=?0.05). Interestingly, this difference exhibited a statistically significant correlation with the corneal thickness (0.03 mmHg per μm corneal thickness; p?=?0.04).

Conclusion

The use of NCT and RT for IOP measurement over a soft contact lens is feasible. The accuracy appears to be sufficient for the most common clinical applications.     

Results of excimer laser penetrating keratoplasty in aphakic eyes

Background

Corneal grafting in aphakic eyes is often challenging. We report about the outcome of excimer laser trephination in aphakic eyes.

Methods

We examined 17 eyes of 17 patients. Diagnosis in 11 eyes was endothelial decompensation and in six, corneal scars. We performed an excimer laser keratoplasty with intraoperative “Flieringa ring” suturing. Follow-up ranged between 3 and 41 (17.6?±?11.7) months. Main outcome measures included: best-corrected visual acuity (BCVA), intraocular pressure (IOP), topographic astigmatism, corneal refractive power (CRP), central corneal thickness (CCT) and endothelial cell density (ECD).

Results

Preoperative BCVA was light perception in two eyes, hand motion in seven, finger counting in one eye, under 20/400 in six eyes and 20/200 in one eye. IOP ranged between 4 and 28 (13.6?±?5.1) mmHg. Topographic astigmatism ranged from 0.5 to 18.5 (7.0?±?6.9) dioptres. CRP was between 38 and 59 (46?±?9) dioptres. CCT was between 404 and 1069 (748?±?181) μm. Postoperative BCVA was hand motion in five eyes, under 20/400 in two and ranged between 20/200 and 20/20 in ten eyes. IOP ranged between 10 and 40 (18.3?±?8.5) mmHg. Topographic astigmatism ranged from 0.9 to 13 (5.5?±?3.2) dioptres. CRP was between 31.9 and 46.7 (42?±?4.1) dioptres. CCT was between 349 and 820 (552?±?115.57) μm. ECD was between 592 and 2319 (1674?±?553) cells/mm².

Conclusions

Excimer laser trephination can deliver beneficial visual outcomes in most of the aphakic eyes.     

Clinical results of selective laser trabeculoplasty in silicone oil-induced secondary glaucoma

Background

To analyze the efficacy of selective laser trabeculoplasty (SLT) on silicone oil-induced secondary glaucoma in terms of intraocular pressure (IOP).

Patients and Methods

42 patients (42 eyes) with silicone oil-induced secondary glaucoma were selected, and SLT was performed with 360° of the trabecular meshwork. During the 12-month follow-up, the complications, IOP, and antiglaucoma medication usage were observed.

Results

The mean IOP decreased from 23.1?±?1.9 mmHg before treatment to 18.4?±?3.7 mmHg after treatment (p?<?0.05). Mean number of antiglaucoma medications used for IOP control also decreased from 2.17?±?1.21 to 1.25?±?0.89 (p?<?0.05). The 12-month success rate in the total sample was 59.5 %. The success rate was 60.7 % (17 eyes) and 57.1 % (eight eyes) for phakic and aphakic eyes, respectively (p?>?0.05)

Conclusions

SLT is a safe and effective option for the treatment of patients with silicone oil-induced secondary glaucoma.     

Einfluss einer Kataraktoperation auf die drucksenkende Wirkung einer Kanaloplastik

Background

The aim of this study was to evaluate the intraocular pressure (IOP)-lowering effect of cataract surgery combined with canaloplasty compared to canaloplasty alone.

Methods

A total of 43 patients underwent canaloplasty without cataract surgery (group K) and 20 patients underwent canaloplasty with cataract surgery (group K+P). The IOP-lowering effect was measured 4–6 weeks, 3, 6 and 12 months postoperatively.

Results

The mean presurgical IOP was 18.26?±?6.07?mmHg in group K and 16.95?±?3.46?mmHg in group K+P. In group K the mean IOP was 13.08?±?5.67?mmHg (28% reduction) 4–6 weeks postoperatively, 13.25?±?4.51?mmHg (27%) 3 months postoperatively, 12.4?±?3.25?mmHg (32%) 6 months postoperatively and 12.5?±?2.45?mmHg (32%) 12 months postoperatively. The mean IOP in group K+P was 11.41?±?4.87?mmHg (33%) 4–6 weeks postoperatively, 10.4?±?4.88?mmHg (39%) 3 months postoperatively, 11.0?±?2.89?mmHg (35%) 6 months postoperatively and 13.0?±?1.94?mmHg (23%) 12 months postoperatively (no statistical significant difference between the two groups).

Conclusions

Combined cataract-canaloplasty surgery has no significant additional IOP-lowering effect compared to canaloplasty alone.