Ocular pulse amplitude and visual field changes in patients diagnosed with aortic regurgitation.

PURPOSE: To examine whether there is a relationship between ocular pulse amplitude (OPA), intraocular pressure (IOP), and visual field (VF) deterioration among the patients diagnosed with aortic regurgitation (AR). METHODS: Twenty-nine patients (average age of 62.06 ± 13.27 years) with AR diagnosis without glaucoma history as AR group and 32 healthy participants (average age 63.81 ± 6.42 years) as control group were included in the study. Routine ophthalmologic examination including VF test [mean deviation (MD), pattern standard deviation (PSD) and VF index (VFI) values were recorded], diurnal IOP and OPA measurements with Pascal dynamic contour tonometry (DCT) was conducted on the patients. VF deficits were classified by Glaucoma Staging System 2 (GSS 2) score. RESULTS: Sixteen (50.0%) of 32 healthy subjects and 14 (48.3%) of 29 AR patients were female (p = 1.000). The measurement conducted at 15:30 among the diurnal IOP measurements performed with the Pascal DCT was found to be statistically significantly higher in the AR group (p = 0.009). While the MD and PSD values of the group diagnosed with AR were determined to be statistically significantly high, the VFI value was found to be significantly low. When the healthy cases and the patients diagnosed with AR were compared, it was observed that there was a statistically significant positive correlation in terms of the significant GSS 2 stage (p < 0.001). CONCLUSION: Although there was no significant increase in IOP, VF deficits were detected in patients with AR. These VF pathologies may be due to the ocular perfusion disorder in AR. However, additional comprehensive studies that also examine perfusion are needed to further confirm this.

Changes in ocular pulse amplitude and posterior ocular structure parameters in type 1 diabetic children without diabetic retinopathy.

Background: It is important to determine changes in posterior ocular structures in the early period before retinopathy develops in pediatric patients with type 1 diabetes mellitus (DM). Objective: To evaluate inner plexiform layer (IPL), ganglion cell layer (GCL), and retinal nerve fiber layer (RNFL) thicknesses, as well as the relationship between choroidal thickness (CT) and ocular pulse amplitude (OPA) in type 1 diabetic children without diabetic retinopathy (DR). Design: A prospective observational study. Methods: Group 1 (n = 44) consisted of pediatric patients with type 1 DM without DR, and Group 2 (n = 65) of pediatric control subjects. Both intraocular pressure (IOP) and OPA were measured using a dynamic contour tonometer. CT, IPL, GCL, and RNFL were all measured using spectral domain optical coherence tomography (OCT). Results: The mean IOP and OPA values were 16.67 ± 2.34 and 1.85 ± 0.34, respectively, in group 1, and 15.14 ± 2.17 and 1.65 ± 0.25 in Group 2 (p = 0.001 for both). The mean subfoveal CT value was 294.30 ± 67.61 µm in group 1 and 394.42 ± 69.65 µm in Group 2 (p < 0.001). The mean GCL and RNFL values were 1.09 ± 0.11 and 96.46 ± 11.69, respectively, in group 1, and 1.14 ± 0.09 and 101.73 ± 9.33 in Group 2 (p = 0.005 and p = 0.008, respectively). Conclusions: IOP and OPA values were higher, and CT, GCL, and RNFL values were lower in children with type 1 DM during the early stages than in the healthy control group. These findings suggest that CT may be a marker of retinal involvement in children with type 1 DM without DR.

Intraocular Pressure Measurement after Penetrating Keratoplasty.

Assessing the intraocular pressure is a difficult but crucial task in the follow-up of patients that have undergone penetrating keratoplasty. Early recognition of elevated intraocular pressure and/or glaucoma and establishment of the appropriate treatment is essential to ensure the best possible visual outcome for patients dealing with this feared complication. Although Goldmann applanation tonometry is still the gold standard for measuring the intraocular pressure, its limitations in postkeratoplasty eyes, due to postoperative modified corneal morphology, have led to the search for more suitable alternatives. This review is the result of a comprehensive literature search in the MEDLINE database that aims to present glaucoma in the context of perforating keratoplasty, the corneal properties with impact on ocular pressure measurement, and the results achieved with the most important tonometers that have been studied in this pathology. Goldmann applanation tonometry remains the reference for intraocular pressure assessment even in corneas after penetrating keratoplasty. However, some promising alternatives have emerged, the most important of which are the Pascal dynamic contour tonometry, the Tono-Pen XL, the ocular response analyzer, and the iCare. All have advantages and disadvantages but have proved to be appropriate alternatives, especially in cases in which Goldmann applanation tonometry cannot be used.

Changes in ocular pulse amplitude and choroidal thickness in childhood obesity patients with and without insulin resistance.

PURPOSE: To compare choroidal thickness (CT) and ocular pulse amplitude (OPA) in childhood obesity with insulin resistance (IR) and without IR. METHODS: Seventy-three childhood obesity and 62 healthy children, who were both age-matched and gender-matched, comprised the study population in this prospective study. Obesity was determined as having a body mass index (BMI) - standard deviation (SD) score that was > 2 SD.Intraocular pressure (IOP) and OPA were measured using a dynamic contour tonometer. The CT measurements were performed using enhanced depth imaging optical coherence tomography at three locations, comprising at the fovea, at a position 500 µm nasal, and also at a position 500 µm temporal to the fovea. RESULTS: Mean BMI value was 28.72 ± 4.85 in the patients with childhood obesity and 21.47 ± 1.14 in the control group. The mean IOP and OPA values were determined 15.90 ± 2.30 and 14.10 ± 2.16 mm Hg, 1.50 ± 0.28 and 1.74 ± 0.32 mm Hg in the patients with childhood obesity and the control group, respectively (p < 0.001, p < 0.001). The mean subfoveal CT value was 350.50 ± 81.51 µm in the eyes with childhood obesity and 390.02 ± 71.50 µm in those of the control group (p = 0.003). When the patient groups with and without IR were compared, no significant difference was found between CT, OPA and IOP values (p > 0.005). CONCLUSIONS: Our results showed that both OPA and CT values were significantly decreased in childhood obesity patients. We suggest further studies to verify longitudinal changes in OPA and CT, as also the evaluation of these parameters in other populations.

Comparison of IOP obtained in different kind of eyes with contact and no contact tonometers.

BACKGROUND: The aim of this study is to analyze and compare the intraocular pressure (IOP) values measured in three different kinds of participants such as healthy subjects (HS), keratoconus patients (KP), and those who underwent myopic photorefractive keratectomy (MPRK). The devices used in this study are the Goldmann Applanation Tonometry (GAT), the dynamic contour tonometry (DCT), the ocular response analyzer (ORA), and the Corvis ST (CST). SUBJECTS AND METHODS: This research included 92 eyes of 92 h, 63 eyes of 63 KP, and 58 eyes of 58 MPRKM. Each participant underwent a complete ophthalmic evaluation and IOP measurement with GAT, DCT, ORA, and CST. A statistical analysis was conducted to detect possible differences and correlations. RESULTS: First, according to the observed data, HS eyes displayed mean IOP values measured with GAT, DCT, ORA, and CST, respectively, 15.82 ± 2.74 mmHg, 17.63 ± 2.28 mmHg, 16.24 ± 3.14 mmHg, and 17.31 ± 3.21 mmHg. Then, KP eyes showed mean IOP values measured with GAT, DCT, ORA, and CST of, respectively, 14.89 ± 1.64 mmHg, 16.97 ± 2.08 mmHg, 13.09 ± 3.12 mmHg, and 13.78 ± 2.11 mmHg. Finally, MPRK eyes showed mean IOP values measured with GAT, DCT, ORA, and CST of, respectively, 13.92 ± 1.34 mmHg, 15.39 ± 2.86 mmHg, 16.63 ± 2.51 mmHg, and 15.06 ± 1.56 mmHg. CONCLUSION: According to the observed data, ORA and GAT might be used interchangeably in HS, whereas GAT, ORA, and CST in KP eyes. Moreover, it has been noticed that in those eyes that previously undergone a myopic PRK, GAT provided lower values of IOP in comparison with other devices.

[Providing eye care during the COVID-19 pandemic]. / Osobennosti okazaniya oftal'mologicheskoi pomoshchi v usloviyakh pandemii COVID-19.

The review presents the data on characteristic features of the new coronavirus infection caused by SARS-CoV-2 and the possibility of its transmission through the eye surface and lacrimal fluid, analyzes the information on eye damage caused by COVID-19, and provides the results of a systematic meta-analysis on the subject. The author describes the system for organizing ophthalmological care in the settings of unfavorable epidemiological situation associated with the COVID-19 pandemic, and considers the preventive measures of infection transmission between patients and medical personnel. The article also gives recommendations for sterilizing medical equipment.

Ganglion cell layer thickening in patients suffering from Obstructive Sleep Apnea-Hypopnea syndrome with long Mean Apnea-Hypopnea Duration during sleep.

PURPOSE: To study the effects of mean apnea-hypopnea duration (MAD), a useful indicator of blood oxygenation, on peripapillary retinal nerve fiber layer (RNFL), macular ganglion cell to inner plexiform layer (GC-IPL) and macular retinal thickness in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). METHODS: Sixty-five patients recently diagnosed with OSAHS and 35 healthy individuals were enrolled in this cross-sectional study. OSAHS patients were divided according to their MAD values into group 1 with 16 participants (MAD:10-15.5 s), group 2 with 17 participants (MAD:15.5-19 s), group 3 with 17 participants (MAD:19-30 s) and group 4 with 15 participants (MAD > 30 s). The average and sectorial values of RNFL, GC-IPL and retinal thickness were measured by SS-OCT (DRI OCT Triton, Topcon). Intraocular pressure was recorded by Goldmann Applanation and Pascal Dynamic Contour Tonometer (DCT-IOP). RESULTS: The average RNFL and retinal thickness values were higher in group 4, but did not reach statistical significance. With the exception of the central 1 mm at the fovea, GC-IPL was always thickened in group 4, and significant differences were evident when its average value was compared with group 2 (p = 0.03), its superior and inferior-nasal values were compared with group 2 (p = 0.02, p = 0.006, respectively) and group 3 (p = 0.01, p = 0.02, respectively), its superior-temporal value was compared with group 3 (p = 0.003) and the control group (p = 0.03), and its superior-nasal value was compared with group 2 (p = 0.03), group 3 (p = 0.001) and the control group (p = 0.03). DCT-IOP was significantly positively correlated with the duration of sleep in which oxygen saturation (SaO2 ) was decreased under 90% (r = 0.359, p = 0.01). CONCLUSION: We report a novel observation of GC-IPL thickening in OSAHS patients experiencing long MAD, a parameter which incorporates the severity of breathing events during sleep. Higher DCT-IOP was noted with advancing hypoxemia.

Significance of dynamic contour tonometry in evaluation of progression of glaucoma in patients with a history of laser refractive surgery.

AIMS: In this study, we tested the hypothesis that intraocular pressure (IOP) parameters measured by dynamic contour tonometry (DCT) would be more relevant in progression of glaucoma when there is a history of laser refractive surgery (LRS) than the IOP parameters measured by Goldmann applanation tonometry (GAT) or calculated by correction formulae. METHODS: Ninety-eight eyes in 54 patients with open-angle glaucoma and a history of LRS were included in this retrospective study. IOP was measured by both GAT and DCT during follow-up. Baseline, mean, and peak IOP, IOP fluctuation, and IOP reduction were measured by each tonometry method. Corrected IOP parameters using central corneal thickness and mean keratometry values were also analysed. Clustered logistic regression was used to identify variables correlated with progression of glaucoma. Areas under the curve (AUCs) for correlated variables were also compared. RESULTS: The mean DCT value (OR 1.36, p=0.024), peak DCT value (OR 1.19, p=0.02) and pattern SD (OR 1.10, p=0.016) were significant risk factors for progression. There was a significant difference in the predictive ability of the mean DCT and GAT values (AUC 0.63 and 0.514, respectively; p=0.01) and of the peak DCT and GAT values (0.646 and 0.503, respectively, p=0.009). The AUCs for corrected IOP did not exceed those of DCT. CONCLUSIONS: IOP measurements were more associated with progression of glaucoma when measurements were obtained by DCT than by GAT or correction formulae in eyes with a history of LRS.

Evaluation of ocular pulse amplitude in patients with carotid artery stenosis using the Pascal dynamic contour tonometer.

BACKGROUND: To evaluate ocular pulse amplitude (OPA) in patients with carotid artery stenosis (CAS) using the Pascal dynamic contour tonometer (DCT). METHODS: Consecutive patients who underwent ultrasound Doppler examination of the carotid artery for the suspicion of CAS were prospectively enrolled in the study. Each patient underwent a complete ocular examination. OPA was measured using Pascal DCT. The participants were divided into four groups according to the degree of CAS: Group 1 (no occlusion, control group), Group 2 (mild occlusion: < 50 per cent), Group 3 (moderate occlusion: 50-69 per cent), and Group 4 (severe occlusion: ≥ 70 per cent). RESULTS: A total of 161 eyes of 81 patients were included in the study. Of the 81 patients, 50 (61.7 per cent) were male, and 31 (38.3 per cent) were female. The mean age was 66.6 ± 12.3 years (range, 20-91 years). Mean OPA values were found to be 2.68 ± 0.97 mmHg in Group 1 (n = 64 eyes), 2.62 ± 0.83 mmHg in Group 2 (n = 49 eyes), 2.30 ± 0.97 mmHg in Group 3 (n = 27 eyes) and 1.66 ± 0.59 mmHg in Group 4 (n = 21 eyes). There was no statistically significant difference in mean OPA levels between Group 1 and Group 2 (p = 0.73). However, statistically significant differences were found between the other groups when they were compared with each other (Groups 1 and 3, p = 0.02; Groups 1 and 4, p < 0.001; Groups 2 and 3, p = 0.02; Groups 2 and 4, p < 0.001; Groups 3 and 4, p = 0.002). CONCLUSION: OPA decreases in patients with moderate to severe CAS. OPA measurement with Pascal DCT can be used as a screening test for CAS.

The Effects of Trabeculectomy on Ocular Pulse Amplitude in Patients with Glaucoma.

OBJECTIVES: This study aimed to investigate whether trabeculectomy and its intraocular pressure (IOP)-lowering effect have an effect on ocular pulse amplitude (OPA) in glaucoma patients. METHODS: Thirty-five consecutive patients with glaucoma (70 eyes) who had undergone unilateral first-time trabeculectomy between April and November 2012 were enrolled in this retrospective study. Patients with intraoperative or postoperative complications were excluded from this study. The eye that underwent trabeculectomy was considered the study eye; the fellow eye was used as the control eye. OPA and IOP were measured by Pascal dynamic contour tonometry (DCT), IOP was measured by Goldmann applanation tonometry (GAT), and systolic and diastolic blood pressure and heart rate were measured before and one month after trabeculectomy. The change in the pre- and postoperative values was compared between the two eyes. RESULTS: The study sample included 17 male and 18 female patients with a mean age of 60.83±13.46 years. The mean preoperative GAT, DCT and OPA values in the study eyes were 24.97±8.26, 31.23±10.55 and 4.22±1.77 mmHg, respectively. One month after trabeculectomy, the GAT, DCT and OPA values were 12.83±4.35, 20.28±7.34 and 2.96±1.66 mmHg, respectively. There was a significant decrease in OPA after filtration surgery in the study eyes (p<0.001), but not in the control eyes (p>0.05). Changes in OPA were positively correlated with changes in IOP (p<0.05), and a significant association was found between OPA and IOP, and as measured by DCT (Regression coefficient = 0.093 [0.041-0.145]) and GAT (Regression coefficient = 0.093 [0.013-0.173]). CONCLUSION: There was a significant decrease in OPA in the eyes that underwent trabeculectomy, and the change in OPA after surgery was significantly different in the study eyes in comparison to the change in OPA in the control eyes. The OPA changes were strongly correlated with the IOP changes in the study eyes.

Do ocular pulse amplitude and choroidal thickness change in patients with thyroid eye disease?

Purpose: The aim of this study was to evaluate whether orbital changes induced by thyroid eye disease affect the ocular pulse amplitude and choroidal perfusion. Materials and Methods: A total of 38 eyes of 38 patients with thyroid eye disease (Group 1) and 38 eyes of 38 control individuals (Group 2) with normal intraocular pressure were enrolled in this study. Thyroid eye disease activity was defined using clinical activity score. Intraocular pressure measurement with Goldmann applanation tonometer, axial length, central corneal thickness, Hertel exophthalmometry and systolic and diastolic blood pressure measurements were taken from each patient. Ocular pulse amplitude and intraocular pressure were measured using dynamic contour tonometry. Choroidal thickness was measured by enhanced depth imaging-optical coherence tomography at subfoveal, nasal and temporal 1000 µm area. Results: Intraocular pressures measured with Goldmann applanation tonometer and dynamic contour tonometry and mean ocular pulse amplitude were not statistically different between groups. However mean choroidal thicknesses were significantly lower when compared to control group. Ocular pulse amplitude and intraocular pressure measurement with dynamic contour tonometry did not change significantly with the increase in clinical activity score. There was not statistically significant correlation between ocular pulse amplitude and choroidal thicknesses in patients with thyroid eye disease. Conclusion: Ocular pulse amplitude and choroidal perfusion were not found to change with orbital involvement in thyroid eye disease and with disease activity, especially in patients with normal intraocular pressure. Although choroidal thickness was thinner than control group, choroidal perfusion did not change as a compensatory mechanism for maintaining ocular homeostasis.

Evaluation of choroidal perfusion changes in obese patients: ocular effects of insulin resistance / Avaliação das alterações da perfusão coroidiana em pacientes obesos: efeitos oculares da resistência à insulina

ABSTRACT Purpose: We aimed to evaluate choroidal per­fusion changes in obese patients using optical coherence tomography and dynamic contour tonometry, to determine whether these changes are associated with body mass index, and to assess the ocular effects of insulin resistance. Methods: We retrospectively evaluated the data of 32 obese patients with body mass index >30 kg/m2 and 45 healthy control individuals. Intraocular pressure and ocular pulse amplitude values of the patients were measured using dynamic contour tonometry, and the mean choroidal thickness was measured using enhanced depth imaging optical coherence tomography. Insulin resistance was assessed using the homeostasis model assessment-estimated insulin resistance index. Results: The mean choroidal thickness (294.30 ± 60.87 μm) and ocular pulse amplitude (2.10 ± 0.74) were lower, whereas the mean intraocular pressure (16.61 ± 2.35 mmHg) was higher in obese patients than in controls. There was a significant negative correlation between body mass index and ocular pulse amplitude (r=-0.274; p=0.029) and an insignificant negative correlation between mean choroidal thickness, intraocular pressure, and body mass index. There was an insignificant negative correlation between homeostasis model assessment-estimated insulin resistance index, mean choroidal thickness, and intraocular pressure and significant ne­gative correlation between homeostasis model assessment-estimated insulin resistance index and ocular pulse amplitude (r=-0.317; p=0.022). Conclusion: We found reduced mean choroidal thickness and ocular pulse amplitude and increased mean intraocular pressure in obese patients. These changes indicated a decrease in choroidal perfusion and ocular blood flow. It may be possible to detect ocular blood flow changes in obese patients through noninvasive assessment using the choroid. The negative correlation between insulin resistance and ocular pulse amplitude may be associated with intracellular fat accumulation in obese patients.

RESUMO Objetivo: Avaliar as alterações da perfusão coroidiana em pacientes obesos utilizando tomografia de coerência óptica e a tonometria de contorno dinâmico, para determinar se essas alterações estão associadas ao índice de massa corporal e avaliar os efeitos oculares da resistência à insulina. Métodos: Foram avaliados, retrospectivamente, os dados de 32 pacientes obesos, com índice de massa corporal >30 kg/m2, e 45 controles saudáveis. Os valores de pressão intraocular e da amplitude de pulso ocular dos pacientes foram medidos por meio de tonometria de contorno dinâmico e a espessura média da coroide foi medida por tomografia de coerência óptica com profundidade de imagem aprimorada. A resistência à insulina foi avaliada usando o índice de estimativa da resistência à insulina pelo modelo de homeostase. Resultados: A espessura média da coroideia (294,30 ± 60,87 μm) e a amplitude de pulso ocular (2,10 ± 0,74) foram menores, enquanto a pressão intraocular média (16,61 ± 2,35 mmHg) foi maior nos obesos do que nos controles. Houve uma correlação negativa significativa entre o índice de massa corporal e a amplitude de pulso ocular (r=-0,274; p=0,029) e uma correlação negativa insignificante entre a espessura média da coroide, a pressão intraocular e o índice de massa corporal. Houve uma correlação negativa insignificante entre a avaliação do modelo de homeostase - estimativa do índice de resistência à insulina, espessura média da coróide e pressão intraocular e correlação negativa significativa entre o modelo de avaliação de homeostase - o índice de resistência à insulina estimado e a amplitude de pulso ocular (r=-0,317; p=0,022). Conclusão: Encontramos redução da espessura média da coroide e da amplitude de pulso ocular e aumento da pressão intraocular em pacientes obesos. Essas alterações indicaram uma diminuição na perfusão coroidal e no fluxo sanguíneo ocular. Pode ser possível detectar alterações no fluxo sanguíneo ocular em pacientes obesos por meio de avaliação não invasiva usando a coróide. A correlação negativa entre a resistência à insulina e a amplitude de pulso ocular pode estar associada ao acúmulo de gordura intracelular em pacientes obesos.

Comparison of Dynamic Contour Tonometry and Non-contact Tonometry in Older Patients Presenting with Headache or Vision Loss.

BACKGROUND: Dynamic Contour Tonometry (DCT) is touted to be the most accurate tonometer for Intraocular Pressure (IOP) measurement. Non-Contact "air puff" Tonometry (NCT) may be the most commonly used tonometer for screening of IOP. Elevated IOP is important to exclude in patients presenting with headache or vision loss. OBJECTIVE: To determine the agreement between DCT and NCT. METHODS: The IOP of adult patients 50 years of age or older presenting with headache or vision loss for possible temporal artery biopsy were prospectively recorded. NCT and DCT measurements were obtained within thirty minutes. The right eye IOP measurements were compared with paired t-test, and Bland- Altman plot analysis. The left eye IOP measurements were subsequently analyzed for confirmation of results. RESULTS: There were 106 subjects with complete right eye data, and 104 subjects with complete left eye data. The average age was 72 years, and 70% were female. The NCT IOP was on average 3.9 mm Hg lower in the right eye, and 3.5 mm Hg lower in the left eye compared with DCT. (p<.001) In the right eye the Bland-Altman analysis showed the 95% agreement interval between the two tonometers was -2.5 to 10.4 mmHg and in the left eye -3.0 to 9.9 mmHg. CONCLUSION: The IOP from NCT and DCT should not be used interchangeably because their level of disagreement includes clinically important discrepancies of up to 10 mm Hg.

Influence of LASEK on Schiøtz, Goldmann and dynamic contour Tonometry.

PURPOSE: Our purpose was to assess the effect of LASEK surgery on ocular rigidity and to compare its effect on intraocular pressure (IOP) readings with Goldmann applanation tonometry (GAT), Schiøtz indentation tonometry (ST) and dynamic contour tonometry (DCT). METHODS: Prospective, observational, single-masked cohort study. One eye per patient from 31 consecutive subjects who underwent LASEK refractive surgery to correct myopia, as well as from 108 non-operated myopic patients, were included. IOP was measured using GAT, DCT, and ST. The coefficient of ocular rigidity (Ko) was obtained from the regression line of the three readings obtained with each weight of the ST. Linear multiple regression analysis was performed with dummy variables to assess the effect of age, central corneal thickness (CCT), and previous refractive surgery on IOP values. RESULTS: Age, CCT, and LASEK surgery explained 23% of the IOP readings with GAT, 11% with DCT, and had no significant influence on ST readings. The IOP readings obtained with GAT and DCT, but not with ST, were significantly different between LASEK and control groups. Significant differences in Ko were observed between LASEK (0.014 mmHg/µL ±0.007) and control groups (0.021 mmHg/µL ±0.013) (P = 0.001). Ko values were not related with age or CCT, in either LASEK or control groups. CONCLUSIONS: ST readings seems to be less affected by LASEK surgery than the other tonometers evaluated. There is a difference in the ocular rigidity between the control and the LASEK eyes that it is not correlated with CCT, so it seems that ST can detect changes in the biomechanical behavior of the LASEK operated corneas.

Ocular pulse amplitude in different types of glaucoma using dynamic contour tonometry: Diagnosis and follow-up of glaucoma.

The aim of the present study was to compare the ocular pulse amplitude (OPA) in patients with different types of glaucoma using dynamic contour tonometry (DCT), to evaluate ocular and systemic factors associated with the OPA and to verify whether OPA measured by DCT is an independent predictor for glaucoma diagnosis. A total of 217 eyes of 217 participants in the following five groups were included in this cross-sectional study: Chronic angle closure glaucoma (CACG), primary open angle glaucoma, normal tension glaucoma (NTG), suspected open angle glaucoma (SOAG) and normal control (NC). The following tests were simultaneously performed during a single visit: Intra-ocular pressure (IOP), OPA, cup-to-disk (C/D) ratio, mean damage (MD) and loss variance (LV). OPAs were compared in each group. The association between OPA and IOP, age, C/D ratio, MD and LV was detected. OPA analysis prior to and after trabeculectomy was also performed to assess its prognostic value. Among the 217 individuals, the OPA was consistent with the IOP, both measured by DCT, along with the MD and LV. Patients with CACG and SOAG had higher OPA values than those with NTG and normal controls. Compared with patients aged >30 years, the OPA was significantly lower in younger patients, while they may not have been affected by different C/D ratios. After trabeculectomy, the OPA had significantly decreased compared with the values prior to surgery. In conclusion, the present study showed that the OPA is correlated with the IOP determined by DCT. CACG and SOAG patients had higher OPA values than patients with other types of glaucoma. OPA measured by DCT may be a predictor for glaucoma diagnosis and prognosis.

Dependence of dynamic contour and Goldmann applanation tonometries on peripheral corneal thickness.

AIM: To determine the effects of peripheral corneal thickness (PCT) on dynamic contour tonometry(DCT) and Goldmann applanation tonometry (GAT). METHODS: A cross-sectional study. We created a software which calculates the corneal contour (CC) as a function of the radius from the corneal apex to each pixel of the contour. The software generates a central circumference with a radius of 1 mm and the remainder of the cornea is segmented in 5 rings concentric with corneal apex being its diameter not constant around the corneal circumference as a consequence of the irregular CC but keeping constant the diameter of each ring in each direction of the contour. PCT was determined as the mean thickness of the most eccentric ring. Locally weighted scatterplot smoothing (LOWESS) regression was used to determine the pattern of the relationship between PCT and both DCT and GAT respectively. Thereafter, two multivariable linear regression models were constructed. In each of them, the dependant variable was intraocular pressure (IOP) as determined using GAT and DCT respectively. In both of the models the predictive variable was PCT though LOWESS regression pattern was used to model the relationship between the dependant variables and the predictor one. Age and sex were also introduced control variables along with their first-degree interactions with PCT. Main outcome measures include amount of IOP variation explained through regression models (R2) and regression coefficients (B). RESULTS: Subjects included 109 eyes of 109 healthy individuals. LOWESS regression suggested that a 2nd-degree polynomial would be suitable to model the relationship between both DCT and GAT with PCT. Hence PCT was introduced in both models as a linear and quadratic term. Neither age nor sex nor interactions were statistically significant in both models. For GAT model, R2 was 17.14% (F=9.02; P=0.0002), PCT linear term B was -1.163 (95% CI: -1.163, -0.617). PCT quadratic term B was 0.00081 (95% CI: 0.00043, 0.00118). For DCT model R2 was 14.28% (F=9.29; P=0.0002), PCT linear term B was -0.712 (95% CI: -1.052, -0.372), PCT quadratic term was B=0.0005 (95% CI: 0.0003, 0.0007). CONCLUSION: DCT and GAT measurements are conditioned by PCT though this effect, rather than linear, follows a 2nd-degree polynomial pattern.

Evaluation of ocular pulse amplitude in non-arteritic anterior ischaemic optic neuropathy.

BACKGROUND: To evaluate the ocular pulse amplitude (OPA) in patients with chronic non-arteritic anterior ischaemic optic neuropathy (NAION). METHODS: This cross-sectional study comprised a study group of 30 eyes from 30 patients with NAION and a control group of 31 eyes from 31 age and gender-matched healthy subjects. Bilateral OPA was measured with dynamic contour tonometry (DCT) and was compared between the study and control groups. RESULTS: No statistically significant difference was found between the study and control groups in terms of hypertension, diabetes mellitus, ischaemic heart disease and hyperlipidemia. The mean intraocular pressure (IOP) measured with Goldmann Applanation Tonometry and DCT in the study and control groups was not statistically different (p1 = 0.094, p2 = 0.240). The mean OPA in the study group and the control group were 2.01 ± 0.69 mmHg and 1.97 ± 0.68 mmHg (p = 0.839). CONCLUSION: No significant difference was determined in the OPA levels of eyes with NAION at the chronic stage and eyes in the control group.

Goldmann Applanation Tonometry versus Dynamic Contour Tonometry after Vitrectomy with Silicone Oil Endotamponade.

PURPOSE: To evaluate the agreement of intraocular pressure (IOP) measurements using dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) in eyes after vitrectomy with silicone oil endotamponade and controls. METHODS: In this prospective comparative study, IOP was measured with GAT and DCT in 30 eyes with oil endotamponade 1-3 days after vitrectomy and 40 untreated controls. In addition, ocular pulse amplitude (OPA), corneal pachymetry (CCT), and axial length (AL) were measured. RESULTS: GAT values in the oil group were significantly higher compared to control eyes (mean GAT oil 13.6 ± 5.1 mmHg; mean GAT control 10.8 ± 2.1 mmHg; p = 0.003). There was no significant difference in DCT measurements (mean DCT oil 12.0 ± 4.1 mmHg; mean DCT control 11.9 ± 2.9 mmHg; p = 0.9). This led to a significant difference of GAT-DCT between the oil and control group (mean difference of GAT-DCT oil 1.6 ± 4.7 mmHg; mean difference of GAT-DCT control -1.1 ± 2.6 mmHg; p = 0.004). The difference between GAT and DCT was negatively correlated with the mean IOP measured by both methods (r = -0.36, p = 0.02) and positively correlated with CCT only in the control group (r = 0.36, p = 0.02), as well as to AL only in the oil group (r = 0.46, p = 0.01). The OPA did not differ significantly between groups. CONCLUSION: GAT and DCT showed a good agreement in control eyes. The difference of GAT and DCT is significantly changed in eyes after vitrectomy with silicone oil endotamponade. Our findings suggest that GAT overestimates IOP in this situation.

[Evaluation of correction formulas for tonometry : The Goldmann applanation tonometry in approximation to dynamic contour tonometry]. / Evaluation von Korrekturformeln für die Tonometrie : Die Goldmann-Applanationstonometrie in Annäherung zur dynamischen Contour-Tonometrie.

BACKGROUND: Accurate determination of intraocular pressure (IOP) is essential for correct management of glaucoma. Goldmann applanation tonometry (GAT) is the gold standard for measuring IOP despite its limitations due to its dependence on corneal properties. With the aim of improving the accuracy of GAT readings, several correction formulas have been developed. OBJECTIVE: The aim of this study was to investigate the accuracy and clinical relevance of five correction equations for GAT. MATERIAL AND METHODS: Prospective study of 112 glaucoma patients at the University Hospital and Talacker Eye Center, Zurich, Switzerland. The IOP was measured with GAT and dynamic contour tonometry (DCT) in randomized order. The GAT readings were adjusted with five correction equations. The primary study endpoint was the degree of concordance between corrected GAT and DCT readings. A discordance of ≥2 mm Hg was defined as significant. The association between discordant IOP measurements and central corneal thickness (CCT) was the secondary study endpoint. RESULTS: The mean patient age was 66 ± 13 years (60% females and 56% left eyes). The mean IOP was 17.0 mm Hg for GAT and 20.3 mm Hg for DCT, with a discordance of 3.3 mm Hg between GAT und DCT. The discordances between DCT and the corrected values ranged from 2.7 to 5.4 mm Hg. Spearman's rank testing showed a positive correlation between CCT and the discordances of all correction equations and a negative correlation between CCT and the discordance of DCT and GAT. CONCLUSION: The use of GAT correction formulas involves the risk of creating significant error. The correction equations examined showed extensive scatter and resulted in mean IOP values that were lower than the IOP initially measured by GAT. Thus the use of any correction equation may delay diagnosis of glaucoma and should be avoided.

Intraocular pressure measurement after DSAEK by iCare, Goldmann applanation and dynamic contour tonometry: A comparative study.

PURPOSE: Corneal thickness inevitably increases following Descemet's stripping automated endothelial keratoplasty (DSAEK), owing to the addition of a donor graft. The current study compares different devices in assessing post-DSAEK intraocular pressure (IOP). METHODS: We compared IOP values measured by the Goldmann tonometry (GAT), iCare rebound tonometry (iCare) and Pascal dynamic contour tonometry (PDCT) in eyes following DSAEK. Agreement between measurements was calculated with correlation analysis and Bland-Altman plots. Effects of keratometry, central, thickness (CCT), endothelial cell density (ECD) and axial length on IOP measurements were assessed with Pearson's correlation. RESULTS: Twenty eyes of 20 patients (mean age 74.3±14.4, 14 females) post-DSAEK were included in this study. There was a high concordance between the IOP readings obtained by the three devices: a strong and significant correlation was found between GAT and PDCT (r=0.94, P<0.001) GAT and iCare (r=0.86, P<0.001) and iCare with PDCT (r=0.81, P<0.001). However, the iCare measurements were significantly and consistently lower than that obtained with GAT (ΔIOP=1.68±2.0, P=0.002, 95% CI: 0.7-2.6) and with PDCT (ΔIOP=1.61±2.5, P=0.01, 95% CI: 0.4-2.8). CCT, ECD, CCT, AXL, corneal curvature or astigmatism did not influence IOP measurement by any instrument. CONCLUSIONS: IOP measurement with three different techniques (applanation, rebound and dynamic contour) showed good correlations, despite an increased corneal thickness following DSAEK. However, the iCare, which is based on a rebound tonometry showed significant lower IOP then the two other methods. This should be taken into account when evaluating patients post DSAEK.