scholarly journals Non-Invasive Ocular Rigidity Measurement: A Differential Tonometry Approach

2015 ◽  
Vol 58 (3) ◽  
pp. 92-97 ◽  
Author(s):  
Efstathios T. Detorakis ◽  
Emmanuela Tsaglioti ◽  
George Kymionis
Keyword(s):  
Anterior Segment ◽  
Applanation Tonometry ◽  
Routine Clinical Practice ◽  
Dynamic Contour Tonometry ◽  
Non Invasive ◽  
Biometric Parameters ◽  
Proposed Model ◽  
Error Coefficient ◽  
Corneal Apex ◽  
Differential Tonometry

Purpose: Taking into account the fact that Goldmann applanation tonometry (GAT) geometrically deforms the corneal apex and displaces volume from the anterior segment whereas Dynamic Contour Tonometry (DCT) does not, we aimed at developing an algorithm for the calculation of ocular rigidity (OR) based on the differences in pressure and volume between deformed and non-deformed status according to the general Friedenwald principle of differential tonometry. Methods: To avoid deviations of GAT IOP from true IOP in eyes with corneas different from the “calibration cornea” we applied the previously described Orssengo-Pye algorithm to calculate an error coefficient “C/B”. To test the feasibility of the proposed model, we calculated the OR coefficient (r) in 17 cataract surgery candidates (9 males and 8 females). Results: The calculated r according to our model (mean ± SD, range) was 0.0174 ± 0.010 (0.0123–0.022) mmHg/μL. A negative statistically significant correlation between axial length and r was detected whereas correlations between r and other biometric parameters examined were statistically not significant. Conclusions: The proposed method may prove a valid non-invasive tool for the measurement method of OR, which could help in introducing OR in the decision-making of the routine clinical practice.

Applanation Tonometry for Assessment of Left Ventricular Systolic Load

2019 ◽  
Vol 12 (2) ◽  
pp. 94-99
Author(s):  
Rene D. Mileva-Popova ◽  
Nina Y. Belova
Keyword(s):  
Arterial Stiffness ◽  
Augmentation Index ◽  
Age Groups ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Applanation Tonometry ◽  
Non Invasive ◽  
Pressure Area ◽  
Older Subjects ◽  
And Gender

Summary Vascular-ventricular coupling is a major determinant of left ventricular load. The aim of our study was to assess non- invasively left ventricular load and its dependency on central hemodynamics. Sixty-five healthy and gender-matched individuals were divided in two groups according to their age: 20y/o and 50y/o. Applanation tonometry was performed using the Sphygmocor device. Central pressures and pulse wave analysis indices were computed. Central systolic (120±3 vs. 98±2 mm Hg) and pulse pressures (43±3 vs. 29±1 mm Hg) as well as the augmentation index (AIx75) (23±3 vs. 6±2%) were significantly higher in the 50y/o group (p<0.01). These parameters are relevant markers of arterial stiffness and evidenced the development of central arterial morphological and functional alterations in the older subjects. The time-tension index (TTI) computed from the systolic pressure area was significantly higher in the 50y/o subjects as compared to the 20y/o group (2378±66 vs. 1954±73 mmHg×s, p<0.01). Moreover, we have shown the presence of significant correlation between TTI and AIx75 (p<0.01) in both age groups. This finding confirmed the contribution of arterial stiffness for the impaired vascular-ventricular coupling. In conclusion, applanation tonometry might be utilized for non-invasive evaluation of the left ventricular load, which is an important parameter of cardiovascular risk.

Comparison of dynamic contour tonometry and Goldmann applanation tonometry following penetrating keratoplasty

2010 ◽  
Vol 45 (5) ◽  
pp. 489-493 ◽  
Author(s):  
Artemios Kandarakis ◽  
Vasileios Soumplis ◽  
Christos Pitsas ◽  
Stylianos Kandarakis ◽  
Jiannis Halikias ◽  
...  
Keyword(s):  
Penetrating Keratoplasty ◽  
Applanation Tonometry ◽  
Goldmann Applanation Tonometry ◽  
Dynamic Contour Tonometry

Results of the project «Optimization of the process of obtaining the service OCT “ (project implementation period 20.06.2019–08.10.2019)

2021 ◽  
pp. 29-37
Author(s):  
Irina Aleksandrovna Rakitina ◽  
Alfiya Gumyarovna Iskhakova ◽  
Evgeny Andreevich Zamytsky ◽  
Marina Vladimirovna Makolina ◽  
Farida Sagitovna Goleeva ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Anterior Segment ◽  
Contact Method ◽  
Optical Coherence ◽  
Non Invasive ◽  
Risk Of Injury ◽  
Eye Tissues ◽  
Implementation Period ◽  
Project Optimization ◽  
Theoretical Foundations

Optical Coherence Tomography (OCT) is a modern, highly accurate, non-invasive study of various eye structures. OCT is a non-contact method that allows a specialist to visualize eye tissue with a very high resolution (1–15 microns), the accuracy of which is comparable to microscopic examination. The theoretical foundations of the OCT method were developed in 1995 by the American ophthalmologist K. Pulafito, and already in 1996–1997 Carl Zeiss Meditec introduced the first device for optical coherence tomography into clinical practice. Today, OCT devices are used to diagnose various diseases of the fundus and anterior segment of the eye. Due to the maximum accuracy, the method of light scanning greatly simplifies the diagnosis of pathologies of the organs of vision, regardless of the cause of their occurrence and the stage of the course. In terms of information content, the technique is not inferior to histology, but the advantage of OCT is the absence of the risk of injury to the eye tissues [1, 2].

scholarly journals Altered Anterior Segment Biometric Parameters in Mice Deficient in SPARC

2017 ◽  
Vol 58 (1) ◽  
pp. 386 ◽  
Author(s):  
Henrietta Ho ◽  
Hla M. Htoon ◽  
Gary Hin-Fai Yam ◽  
Li Zhen Toh ◽  
Nyein Chan Lwin ◽  
...  
Keyword(s):  
Anterior Segment ◽  
Biometric Parameters

scholarly journals Safety and efficacy of posterior iris claw intraocular lens fixation in aphakic patients

2018 ◽  
Vol 16 (2) ◽  
pp. 124-133
Author(s):  
Rosemary Tomy ◽  
Rajkumar Maheshwari ◽  
Ansa Parveen Kunhu Muhammed ◽  
Venkataramana Kalikivayi ◽  
Sajeev Cherian Jacob
Keyword(s):  
Intraocular Lens ◽  
Anterior Segment ◽  
Case Series ◽  
Visual Outcome ◽  
Applanation Tonometry ◽  
Long Term Results ◽  
Retrospective Case ◽  
Case Series Study ◽  
Wide Range

Purpose: To assess the indications and visual outcome of eyes undergoing posterior iris fixated intraocular lens (IFIOL) implantation for aphakia, to identify reasons for poor visual outcome, and report occurrence of complications. Methods: In this retrospective case series study, all cases of posterior IFIOL fixation performed over a 30-month period were identified retrospectively. Preoperative and postoperative evaluations comprised objective and subjective refraction, best corrected visual acuity (BCVA), slit lamp biomicroscopy, applanation tonometry, and dilated fundus examination. Results: Fifty-six eyes of 56 patients were analyzed. Mean age was 60.55 ± 17.2 years. The most common indication for IFIOL implantation was surgical aphakia following complicated cataract surgery (n = 33; 58.9%) followed by trauma (n = 10; 17.9%), dropped nucleus/IOL during primary surgery (n = 6; 10.7%), and subluxated/dislocated lens-induced glaucomas (n = 5; 8.9%). BCVA better than or equal to their preoperative BCVA was achieved in 96.43% patients. The surgical aphakia and paediatric/adolescent groups had the best visual results while the dropped nucleus/IOL group and subluxated lens-induced glaucoma groups fared poorly. On the long-term follow-up visit, the most common complication noted was pigment dusting on the corneal endothelium (65.7%). Conclusion: The long-term results suggest that posterior IFIOL implantation is a safe and effective method for correction of aphakia and can be used for a wide range of indications in eyes without adequate capsule support. It may be considered an easier and faster alternative with minimal manipulation to anterior segment structures in paediatric and post-traumatic aphakic eyes.

scholarly journals Travoprost- and Tafluprost-induced Changes in Intraocular Pressure and Ocular Pulse Amplitude

2021 ◽  
Vol 62 (9) ◽  
pp. 1235-1242
Author(s):  
Gyeong Min Lee ◽  
Seung Joo Ha
Keyword(s):  
Intraocular Pressure ◽  
Open Angle Glaucoma ◽  
Pulse Amplitude ◽  
Applanation Tonometry ◽  
Dynamic Contour Tonometry ◽  
Long Term Effects ◽  
Ocular Pulse Amplitude ◽  
Induced Changes ◽  
First Time ◽  
Ocular Pulse

Purpose: To compare the intraocular pressure reduction and changes in ocular pulse amplitude of travoprost 0.003% and tafluprost 0.0015%. Methods: We assessed patients who were diagnosed with open-angle glaucoma from January 2017 to July 2019 for the first time at our hospital. Forty-two eyes were assigned to the travoprost group (23 patients) and 26 eyes were assigned to the tafluprost group (14 patients). Changes in intraocular pressure were measured by Goldmann applanation tonometry (GAT), and corrected ocular pulse amplitude (cOPA) was measured using dynamic contour tonometry. Changes in these parameters were observed and compared for 1 year. Results: No significant differences were observed between the GAT measurements and the cOPA of patients treated with travoprost and tafluprost for 1 year (p = 0.512, p = 0.105). The change in initial intraocular pressure on GAT observed after 1 week was -5.32 ± 2.63 mmHg for travoprost and -3.79 ± 3.19 mmHg for tafluprost (p = 0.0457). The initial change in cOPA was +0.04 ± 0.9 mmHg in the travoprost group and -0.76 ± 0.97 mmHg in the tafluprost group (p = 0.0028). Conclusions: Travoprost and tafluprost reached the targeted intraocular pressure with no difference in the long-term effects of reduced intraocular pressure. However, travoprost was initially better at lowering intraocular pressure faster, and tafluprost had a greater effect on lowering OPA. Prostaglandin analogs can be selected individually by considering the aforementioned factors.

Management of Glaucoma Following Intraocular Procedures

Glaucoma ◽  
2012 ◽  
Author(s):  
Raghu C. Mudumbai
Keyword(s):  
Refractive Surgery ◽  
Structural Integrity ◽  
Corneal Thickness ◽  
Topical Steroid ◽  
Applanation Tonometry ◽  
Dynamic Contour Tonometry ◽  
Glaucomatous Optic Neuropathy ◽  
Clinical Appearance ◽  
Clinical Procedures ◽  
Pressure Spike

The development of glaucoma can occur postoperatively from corneal/refractive, cataract, and vitreoretinal surgery. Additionally, glaucoma may be noted after clinical procedures have been performed, including injections and laser procedures. This chapter is organized into two basic sections: postoperative and post-procedure glaucoma. Background: Currently little is known about the effect of refractive surgery in glaucoma patients or about patients who undergo refractive procedures and may go on to develop glaucoma. •IOP measurement •Measurement of IOP after refractive surgery can be challenging. Corneal properties that are altered after refractive surgery include corneal thickness, corneal curvature, the structural integrity (stiffness or hysteresis), as well as the overlying tear film that interacts with instruments that measure IOP. Photorefractive keratectomy (PRK) additionally ablates portions of Bowman’s layer, which may change corneal resistance. Nomograms have been developed to adjust for IOP change after corneal alteration but usually take only corneak thickness into account, which has led to little success in their use. •Goldmann applanation tonometry (GAT) assumes corneal thickness = 520 microns. Thicker corneas will overestimate IOP and thinner corneas, which result from refractive procedures such as PRK and LASIK, will underestimate IOP. Therefore, GAT may have limited value in measuring true IOP following refractive surgery. Other tonometric devices, like Pascal dynamic contour tonometry, pneumatonometry, and the Reichert ocular response analyzer, may be more accurate. There does not appear to be any simple conversion table that can be referenced in correcting measured IOP after the cornea is altered surgically. Preoperative IOP is probably the most important variable that should be recorded. •The intraoperative pressure spike associated with LASIK may occur in select patients, leading to the development of glaucomatous optic neuropathy. • Pressure-induced stromal keratitis (PISK) is a condition related to steroid-induced elevated IOP that may occur after LASIK. The clinical appearance is similar to diffuse lamellar keratitis (DLK), where there is a diffuse interlamellar haze covering the flap. DLK is an inflamatory response where IOP is not elevated and requires topical steroid treatment for resolution.

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