Current Trends in Tonometry and Tonometer Tip Disinfection.

PRECIS: A survey among members of the American Glaucoma Society (AGS) and the American Optometry Association (AOA) on tonometer preference and tonometer disinfection indicates a shift to disposable tonometer tips compared with 1987. PURPOSE: This survey's purpose was to determine how eye care providers responded to the 2008 Centers of Disease Control (CDC) tonometer disinfection guidelines, which recommend 10% hypochlorite (dilute bleach) for reusable tonometers. Tonometers measure the eye pressure when they touch the cornea, an essential part of the eye examination. METHODS: AGS and AOA members were surveyed on tonometer preference, tonometer use, disinfection process, disinfectants, disinfection timing, and tonometer damage. RESULTS: Survey responses from 79 AOA members and 197 AGS members are included. The Goldmann tonometer is considered most accurate (70, 89% AOA and 161, 82% AGS). It is preferred by 54 (70%) AOA and 193 (98%) AGS members. Many providers (165) use reusable Goldmann tonometer tips (77, 79% AOA, 88, 45% AGS), and most clean with 70% isopropyl alcohol wipes 59 (77%) AOA and 54 (61%) AGS. In summary, 126 of 276 participants (8, 10% AOA and 118, 60% AGS) follow CDC guidelines by using disposable tips (2 AOA and 109 AGS) or disinfecting reusable tips with 10% hypochlorite (6 AOA and 9 AGS). CONCLUSIONS: The majority of AGS providers follow current CDC tonometer disinfection guidelines by shifting to disposable Goldmann tonometer tips. Only a minority of providers who use reusable tonometer tips disinfect with dilute bleach. Continued education on proper tonometer disinfection is critical to prevent eye-care related infection due to improper disinfection.

Uso de pantallas de visualización de datos e hipertensión ocular en trabajadores de la Administración local / Use of data displai screens and ocular hypertension in local public sectorworkers

Objetivo: El objetivo principal de este estudio es conocer la relación entre la exposición al trabajo con pantallas de visualización de datos (PVD) y la hipertensión ocular (HTO).Métodos: Estudio transversal en población trabajadora en la Administración local (Diputación Provincial de Valencia).Se recogieron datos de 620 personas a lo largo de 25 meses, en una Unidad de Salud Laboral, aprovechando los registros efectuados durante el examen de salud periódico. La presión intraocular (PIO) se obtuvo con un tonómetro de rebote portátil y validado para screening, estableciéndose el punto de corte para HTO en 22 mmHg. Como covariables se tuvieron en cuenta características biológicas y otras relacionadas con el trabajo. Se efectuó estadística descriptiva de los datos, pruebas no paramétricas con nivel de significación del 95% y regresión logística con p<0,1 como nivel de significación de la prueba de verosimilitud. Resultados: La media de edad de la población estudiada es de 52,8 años. La prevalencia de HTO es del 3,5% (el 5,1%en los hombres y el 1,2%en las mujeres; p=0,012). No se han encontrado diferencias significativas en HTO en cuanto a horas diarias de exposición a PVD (p=0,395). La regresión logística corrobora la relación entre HTO y el sexo, afectando menos a las mujeres (OR = 0,234; IC95%: 0,068-0,799; p=0,020).Conclusiones: No se ha encontrado relación entre la hipertensión ocular y el tiempo de exposición a pantallas de visualización de datos (PVDs). La regresión logística apunta hacia cierta relación entre la hipertensión ocular y el sexo, con mayor predisposición hacia los hombres

Objective: The main objective of this study is to examine the association between work with data display screens (DDS) and ocular hypertension (OHT). Methods: A cross-sectional study among local public sector workers (Diputación Provincial de Valencia). Data from 620 people were collected over 25 months, from periodic medical examinations performed at an occupational health unit. Intraocular pressure (IOP) was obtained with a portable puff tonometer validated for screening, establishing the cut-off point for OHT at 22 mmHg. Both biological characteristics and other work-related variables were taken into account as covariates. Descriptive statistics of the data were obtained, together with nonparametric tests with a level of significance of 95% and logistic regression with p<0.1 as the level of significance of the likelihood test. Results: The average age of the study population is 52.8 years. The prevalence of OHT was 3.5% (5.1% among men and 1.2% among women; p = 0.012). No significant associations were found between hours of DDS-related work and OHT were found (p = 0.395). Logistic regression corroborated the association between gender and OHT, with women less affected (OR = 0.234; 95%CI: 0.068-0.799; p=0.020). Conclusions: In our study, no associations were found between time of exposure to data display screens and ocular hypertension. Logistic regression points to a certain association between ocular hypertension and gender, with men being more predisposed

Concordancia entre la tonometría de aplanación de Goldmann y la tonometría de contorno dinámico: efectos de la morfometría corneal / Comparison of Goldmann applanation and dynamic contour tonometry measurements: effects of corneal morphometry

Objetivos: Determinar la concordancia entre la presión intraocular (PIO) medida mediante tonometría de aplanación de Goldmann (TAG) y tonometría de contorno dinámico (TCD).MétodosLa PIO se midió mediante TAG y TCD en 63 ojos de 63 voluntarios sanos. La concordancia se determinó mediante coeficiente de correlación intraclase (CCI). Se empleó el método de Passing-Bablok para establecer la presencia de sesgos proporcionales y/o sistemáticos. El análisis de regresión multvariable se empleó para determinar si las diferencias estaban condicionadas por la potencia de los ejes mayor y menor de la córnea, por su orientación, por el grosor corneal central (GCC) y por la edad.ResultadosEl CCI fue 0,57 (intervalo de confianza [IC] al 95%: 0,29-0,74). La diferencia media entre los dos instrumentos fue 1,68mmHg (TCD menos TAG) (IC 95%: 0,92-2,44). El análisis de Passing-Bablok (X=DCT, Y=GAT) reveló la presencia de un sesgo sistemático (A=-14,35, IC 95%: -24,51-[-9,14]) y otro proporcional (B=1,74, IC 95%: 1,43-2,26). El análisis de regresión multivariable mostró una total independencia del TCD de las características corneales mientras que la TAG estaba afectada por el GCC (B=0,042 CI 95%: 0,002-0,082).ConclusionesLa TCD se mostró independiente de las características morfométricas de la córnea mientras que la TAG se afectó por el GCC (AU)

Objectives: To compare intraocular pressure (IOP) measurements made by Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT).MethodsIOPs were measured by GAT and DCT in 63 eyes of 63 healthy subjects. A comparison was made by intraclass correlation coefficient. Passing-Bablok plot was constructed to establish the existence of systematic and/or proportional biases. Multivariate regression analysis was used to examine whether the measurements of both instruments were affected by the power of the steepest and flattest corneal axes, their orientation, age or central corneal thickness (CCT).ResultsThe intra-class correlations (ICCs) were 0.57 (95% confidence interval (95% CI): 0.29-0.74). Mean differences were 1.68 (DCT minus GAT) (95% CI: 0.92-2.44). Passing-Bablok analysis (X=DCT, Y=GAT) revealed a systematic bias (A=-14.35, 95% CI: -24.51-[-9.14]) and a proportional bias (B=1.74, 95% CI: 1.43-2.26). Multivariate regression analysis revealed that the DCT was independent of the corneal characteristics analysed while GAT was biased by CCT (B=0.042, 95% CI: 0.002-0.082).ConclusionsWhile GAT was biased by corneal CCT; DCT readings were independent of corneal morphometry (AU)

Self-tonometry in glaucoma management--past, present and future.

Glaucoma is the leading cause of irreversible blindness in the world. Diagnosis and management of glaucoma is significantly associated with intraocular pressure, but contemporary office-based measurements are not sufficient to discover diurnal changes and spikes, nor do they demonstrate the effect of medication and compliance. Patient-directed self-tonometry can be taken throughout the day and is therefore the subject of much discussion and research. In this article we review the history of self-tonometry devices and present technologies for the future.

Evaluación de cuatro nuevas funciones discriminantes del HRT II para el diagnóstico del glaucoma / Evaluation of four new discriminant functions for HRT II glaucoma diagnosis

Objetivo: Valorar la capacidad diagnóstica de cuatro fórmulas discriminantes diseñadas para el Heidelberg retina Tomograph (HRT) II a partir de nuestra población. Material y método: Se incluyeron 450 ojos de 450 pacientes. Fueron clasificados según la presión intraocular, morfología papilar en estereofotografías y los resultados de la perimetría automatizada convencional en 101 ojos normales, 126 hipertensos oculares, 121 sospechosos de glaucoma y 102 ojos con glaucoma. Se calcularon las ANOVAs entre los grupos para todos los parámetros globales y las cuatro fórmulas. Se trazaron las curvas ROC para las cuatro funciones discriminantes diseñadas en nuestro hospital y se compararon las áreas bajo las curvas. Se calcularon los valores de sensibilidad para especificidades fijadas en el 80% y 90%. Resultados: Las cuatro fórmulas discriminaron bien entre el grupo control y los sospechosos de glaucoma, y entre controles y glaucomas. Para una especificidad fijada en el 90%, las sensibilidades oscilaron entre el 54% y 60% para diferenciar entre sanos y sospechosos de glaucoma, y entre el 65% y 68% para diferenciar entre sanos y glaucomas. No se observaron diferencias en las áreas bajo la curva de las distintas fórmulas. Conclusiones: Las fórmulas discriminantes evaluadas aumentaron la capacidad diagnóstica de los parámetros aislados del HRT II para detectar glaucomas. Asimismo, mostraron mejor rendimiento que las fórmulas discriminantes incluidas en el HRT

Purpose: To assess the diagnostic usefulness of four linear discriminant functions for Heidelberg retina tomograph (HRT) II obtained in our population. Methods: 450 eyes of 450 patients were studied. Eyes were classified as those of healthy subjects (101), those with ocular hypertension (126), those suspected to have glaucoma (121) or those with glaucoma (103). Intraocular pressure, optic nerve head appearance in stereophotographs, and standard automated perimetry results were assessed. ANOVAs among the groups were calculated for all global parameters and the 4 formulas. Receiver operating characteristic (ROC) curves were plotted for the 4 multivariate functions designed in our hospital and the areas under the ROC curves were compared. Sensitivity at 80% and 90% fixed specificities were also calculated. Results: All functions discriminated well between healthy and glaucoma suspects, and between healthy and glaucomatous eyes. At 90% fixed specificity, sensitivities ranged from 54% to 60% in differentiating between healthy and glaucoma suspects, and from 65% to 68% in discriminating between control and glaucoma subjects. No differences were found between the areas under the ROC curves of these functions. Conclusions: The evaluated linear discriminant functions increased the diagnostic ability of HRT II isolated parameters in detecting glaucoma. These functions performed better than the HRT-provided discriminant functions (Arch Soc Esp Oftalmol 2008; 83: 349-356)

Tratamiento con antioxidantes / Antioxidants treatment of ocular diseases

No disponible

Variabilidad diurna de la presión intraocular / Diurnal variability of intraocular pressure

Objetivo: Comprobar y cuantificar la posible variación de los valores de presión intraocular (PIO) en sujetos sanos, entre la mañana y la tarde. Métodos: Estudio descriptivo y transversal realizado en un Centro de Salud entre los consultantes habituales de una consulta de medicina general. Se realizaron dos tomas de presión intraocular el mismo día (la primera entre las 8 y las 9 horas y la segunda entre las 17 y las 18 horas) utilizando un tonómetro de aplanación tipo Perkins. Los sujetos (119 mujeres y 101 hombres, edad media de 46,3 años con un rango entre 14 y 83) estaban distribuidos proporcionalmente en cuatro grupos de edad (14-24, 25-44, 45-64 y >65 años). Resultados: Los valores medios de PIO fueron: Ojo derecho en la mañana y en la tarde 13,29 y 11,81 (p<0,001) respectivamente y Ojo izquierdo en la mañana y en la tarde 13,48 y 12,04 (p<0,001). La PIO fue significativamente mayor en hombres que en mujeres, teniendo una correlación muy débil con la edad. Conclusiones: Constatamos una diferencia en los valores de PIO entre la mañana y la tarde, de aproximadamente 1,5 mmHg. El momento del día en que se determina la PIO debería contemplarse como una variable más en los estudios de hipertensión ocular y glaucoma que la determinan

Objective: To assess whether there are variations in the intraocular pressure (IOP) between the morning and afternoon in healthy subjects. Methods: This study was carried out in a Primary Care Health Center among usual patients of general practitioners. Two measurements of the intraocular pressure were assessed on the same day (between 8 and 9 a.m. and between 5 and 6 p.m.) using a Perkins applanation tonometer. The subjects (119 females and 101 males) had a mean age of 46.3 years, with ages ranging between 14 and 83 years. They were proportionally distributed among 4 age groups (14-24, 25-44, 45-64 and >65 years). Results: The IOP mean values were: right eye, morning time and afternoon, 13.29 and 11.81 mm Hg, respectively (p<0.001); left eye, morning time and afternoon, 13.48 and 12.04 mm Hg (p<0.001). The IOP was significantly higher in males than in females, and showed a weak association with age. Conclusions: We found a diurnal variation of IOP of approximately 1.5 mm Hg. The time of day when the IOP is measured needs to be considered as a variable in research in ocular hypertension and glaucoma

Update in tonometry. Phosphene and rebound tonometries, self-tonometry and technologies for the future.

The Proview phosphene (eye-pressure) tonometer and the Rebound tonometer ICare are relatively new devices basically different from the Goldmann applanation tonometry (GAT). Both technologies will be presented in this review with respect to their principle, their technique, their advantages and limits, as well as their accuracy, the IOP measurements agreement with GAT, and the influence of central corneal thickness on the reliability of these measurements. Because the current data base for the interpretation of glaucoma disease course and its management are still relatively small, the development of a continuous, accurate, reliable and harmless monitoring of IOP over 24 hours is strongly desirable in the future. Approaches for self-tonometry and devices such as smart contact lenses which can take the IOP from the corneal surface have been developed with this goal. The future will probably confirm whether telemetric IOP monitoring with an implantable active microsystem allows a reliable IOP monitoring or not. In any case, active implants will open new and important perspectives in the diagnosis and the treatment of glaucomatous optic neuropathy.

Comparación del tonómetro Pascal(R) con el neumotonómetro y el tonómetro Goldmann / Comparison of dynamic contour tonometry (Pascal(R)) with pneumotonometry and goldmann tonometry

Objetivo: Comparar la medición de presión intraocular con el tonómetro de Pascal(R) en córneas normales frente al tonómetro de Goldmann y al pneumotonómetro. Método: Estudio clínico observacional en el que se han incluido 205 pacientes consecutivos y randomizados que han acudido a la consulta de oftalmología. Se realiza una medición con cada tonómetro en orden aleatorio. Resultados: El Pascal(R), dio una medición de la presión intraocular mayor que la del resto de tonómetros. Se obtienen diferencias significativas del Pascal(R) frente a los otros dos tonómetros (p<0,05). La fiabilidad del Pascal(R) fue: fiables en el 27,3% (56 de 205 pacientes), aceptable en el 42% (86 de 205 pacientes) y en el 23,4% (48 de 205 pacientes) inaceptable. En el 7,3% (15 de 205 pacientes) restante no se obtuvo ninguna medición con el tonómetro de Pascal(R). Al comparar el tonómetro de Pascal(R) frente al de Goldmann y al neumotonómetro se observa que el coeficiente de correlación es débil y presenta alta discordancia con el método de Bland- Altman. Conclusión: Diversos autores han comparado el tonómetro de Pascal(R) y el Goldmann coincidiendo todos en que el Pascal(R) ofrece una presión intraocular mayor que el Goldmann con unas diferencias que van de 0,7 a 4,4 mmHg. En córneas patológicas es muy difícil realizar la medición y cuando ésto ocurre ésta suele ser informada como inaceptable

Purpose: To compare the intraocular pressure measurements as defined by the Pascal(R) tonometer, the Goldmann tonometer and the pneumotonometer. Methods: This was an observational clinical study, which included two hundred and five randomly selected subjects recruited from the Ophthalmology Department. The intraocular pressure measurements were performed with each tonometry technique in a randomized order. Results: The Pascal(R)’s intraocular pressure measurement was significantly higher than that measured by the other two tonometers (p<0.05). The quality data of Pascal(R) was: optimum in 27.3% (56 of 205 patients), acceptable in 42%(86 of 205 patients) and unacceptable in 23.4% (48 of 205 patients). In 7.3% (15 of 205 patients) it was impossible to obtain any measurement using Pascal®. A weak correlation coefficient between the Pascal(R) and the Goldmann, and between Pascal® and the pneumotonometer was found. The Bland-Altman method of measurement using these tonometers showed a high degree of discordance. Conclusion: As reported by others authors, the Pascal (R)’s intraocular pressure measurement is higher than that of the Goldmann tonometer. The measurement differs from 0.7 to 4.4 mmHg. In corneas with pathology, it is very difficult or even unacceptable to measure the intraocular pressure using the Pascal (R) tonometer

Tonometría de rebote en la práctica clínica. Comparación con tonometría de aplanación / Rebound tonometry in a clinical setting. comparison with applanation tonometry

Objetivo: La tonometría de rebote ha sido recientemente adaptada para su utilización en humanos. El objetivo de nuestro estudio es determinar la precisión del tonómetro de rebote (TRB) ICare(R) en comparación con el tonómetro de aplanación Goldmann (TAG). Métodos: Se reclutaron pacientes de la Unidad de Glaucoma de nuestro centro. En cada paciente se midió la presión intraocular (PIO) con el TRB sin anestésico y tras diez minutos con el TAG. Se empleó la paquimetría para determinar el grosor corneal central (ECC). Resultados: Se reclutaron 68 pacientes (132 ojos). La media de PIO obtenida con el TRB fue de 18,9 [Desviación estándar (DE) 7,2 mmHg] y de 15,5 (DE 5,7 mmHg) con el TAG (p<0,001). Existe una buena correlación entre los dos aparatos (r = 0,87, p<0,001). En la mayoría de los casos (84,6%) la PIO obtenida con el TRB fue mayor que la obtenida con el TAG. La diferencia media entre los dos instrumentos fue de 3,4 (DE 3,6 mmHg). Se aprecia una tendencia a la sobreestimación de la PIO con el TRB, siendo ésta mayor para valores de PIO más elevados medidos con TAG. Se encontró una correlación estadísticamente significativa de la PIO obtenida con ambos tonómetros y el ECC, con mayor sobreestimación con TRB cuanto mayor es la paquimetría. Conclusiones: El TRB puede ser aplicado en la práctica clínica teniendo en cuenta que habitualmente sobreestima la PIO con respecto al TAG. Podría ser especialmente útil en campañas de screening de glaucoma al poder ser manejado por técnicos entrenados

Purpose: Rebound tonometry has recently been modified for its use in humans. The purpose of our study was to determine the precision of the ICare(R) rebound tonometer (RBT) as compared with the Goldmann applanation tonometer (GAT). Methods: Patients were recruited from our Hospital’s Glaucoma Unit. In each patient, intraocular pressure (IOP) was measured without anaesthesia using the RBT and ten minutes later using the GAT. Central corneal thickness (CCT) was measured by pachymetry. Results: Sixty-eight patients were recruited (132 eyes). Mean IOP readings with RBT were 18.9 ± 7.2 (SD) mmHg and were 15.5 ± 5.7 mmHg with GAT (p<0.001). There was a good correlation between both instruments (r = 0.87, p<0.001). In most cases (84.6%) the IOP measured with the RBT was greater than that measured with the GAT. The mean difference between both instruments was 3.4 ± 3.6 mmHg. There was a trend towards greater differences between those obtained using the RBT than the GAT when IOP values were higher. A statistically significant correlation was found between IOP readings with both tonometers and CCT, with higher differences being seen as the CCT increased. Conclusion: The RBT can be employed in a clinical setting taking into account that it usually overestimates IOP as compared with the GAT. It could be especially useful in glaucoma screening campaigns since it can be operated by a trained technician

[New trends in tonometry]. / Neue Trends in der Tonometrie.

BACKGROUND: Though the knowledge about the risk of elevated intraocular pressure for pathogenesis for development and progress of glaucoma is more than 400 years old. It took another 300 years before by means of tonometry this elevation could be quantified. After discussion of the key words it is our aim to demonstrate the latest trends in tonometry, specifically by use of modern electronics for instrument design. MATERIALS: Goldmann was the founder of the "applanation tonometry", measuring the corelation of applanated area and applied force. Here, the next step was the development of instruments, measuring independent of position or gravity to allow application also at the lying patient. Electronic area detection was the next step to avoid examinor's error. Also important was the introduction of automatic UV-desinfection to avoid contamination of the other eye or other patients. Other tonometers control the force applied by an inductive method, which also allows application independent of position. Airpuff-tonometry uses completely different measuring principles - the resulting change of corneal curvature indicates the intraocular pressure. The impedance principle is applied even through the closed eye lid. The shock waves resulting shall be measured. Direct application of a surface sensor incorporated into a concave surface contact body shall allow direct measurement of intraocular pressure independent of corneal thickness, curvature, astigmatism. This method has been tried for more than 20 years. Also exposition of the eye to count waves of different frequency was an early attempt. Here also change of reflectivity is used to calculate intraocular pressure. CONCLUSIONS: Even after use of modern electronic technology the precision of many of these new devices does not lead to better results. This specifically is shown by modern calibration methods.

[Progress in early detection and follow up of glaucoma]. / Fortschritte bei der Früherkennung und Verlaufskontrolle des Glaukoms.

The importance of Hans Goldmann's contributions to clinical tonometry is discussed in detail. One example is the principle of an applanation diameter of 3.06 mm, which was established by him and is still the basis for the various methods of clinical tonometry today. Therefore, further advances in this field can only be concerned with facilitating the application of this principle. An instrument which can be used by both physician and patient is described. By facilitating more frequent tonometric examinations it would ensure much better glaucoma control than is at present possible. A further application of a self-test tonometer of this kind, which is not affected by gravity, is space medicine. It is planned to use the instrument in the German Spacelab D2 mission in 1991.

Cost and quality implications of changes in tonometry use by optometrists.

Tonometry, as a test for glaucoma, traditionally was performed routinely only on patients over age 40. In 1974 in the Helling v. Carey case the Supreme Court of Washington (state) held that an ophthalmologist was negligent in failing to administer a glaucoma test to a patient under age 40, and thus failing to diagnose primary open angle glaucoma. In a study performed at the Pennsylvania College of Optometry and the Optometric Center of Maryland an increase of utilization of tonometry on patients under the age of 40 was measured. Available literature indicates that this change occurred nationwide for optometrists in private practice. This change may result in an additional cost for eye care, without a strong indication of an improvement in quality of care.