Comparison of intraocular pressure measurements using Goldmann tonometer, I-care pro, Tonopen XL, and Schiotz tonometer in patients after Descemet stripping endothelial keratoplasty

Intraocular pressure measurement and association with corneal biomechanics in patients underwent Descemet's stripping with endothelial keratoplasty: a comparative study

Purpose

To compare corneal biomechanical properties and intraocular pressure (IOP) measurements in patients who underwent Descemet's stripping with endothelial keratoplasty (DSEK) with those of the follow healthy eyes.

Methods

In this retrospective comparative study, a total of 35 eyes of 35 patients who underwent DSEK by a single surgeon from 2015.02 to 2019.12 were enrolled along with their fellow healthy eyes. Corneal biomechanical parameters were assessed at least 3 months post-DSEK using Corneal Visualization Scheimpflug Technology (CST). IOP was measured by CST, Goldmann applanation tonometry (GAT), and MacKay-Marg tonometer.

Results

Central corneal thickness (CCT) and stiffness parameter at first applanation (SP-A1) were significantly increased after DSEK when compared to the fellow eyes. In DSEK eyes, biomechanically-corrected intraocular pressure (bIOP) and MacKay-Marg IOP correlated significantly with GAT IOP measurements, with bIOP showed the lowest IOP values. All the IOP values did not correlate with CCT. However, GAT-IOP and MacKay-Marg IOP showed a positive correlation with SP-A1.

Conclusion

The corneal stiffness increased after DSEK. Central corneal thickness may have less influence than corneal biomechanics on IOP measurements in eyes after DSEK. Biomechanically-corrected IOP obtained by CST seemed to be lower than other tonometry techniques in DSEK eyes, perhaps because of correction for corneal stiffness, CCT and age.

Advancing glaucoma detection with convolutional neural networks: a paradigm shift in ophthalmology

A leading cause of irreversible vision loss, glaucoma needs early detection for effective management. Intraocular Pressure (IOP) is a significant risk factor for glaucoma. Convolutional Neural Networks (CNN) demonstrate exceptional capabilities in analyzing retinal fundus images, a non-invasive and cost-effective imaging technique widely used in glaucoma diagnosis. By learning from large datasets of annotated images, CNN can identify subtle changes in the optic nerve head and retinal structures indicative of glaucoma. This enables early and precise glaucoma diagnosis, empowering clinicians to implement timely interventions. CNNs excel in analyzing complex medical images, detecting subtle changes indicative of glaucoma with high precision. Another valuable diagnostic tool for glaucoma evaluation, Optical Coherence Tomography (OCT), provides high-resolution cross-sectional images of the retina. CNN can effectively analyze OCT scans and extract meaningful features, facilitating the identification of structural abnormalities associated with glaucoma. Visual field testing, performed using devices like the Humphrey Field Analyzer, is crucial for assessing functional vision loss in glaucoma. The integration of CNN with retinal fundus images, OCT scans, visual field testing, and IOP measurements represents a transformative approach to glaucoma detection. These advanced technologies have the potential to revolutionize ophthalmology by enabling early detection, personalized management, and improved patient outcomes. CNNs facilitate remote expert opinions and enhance treatment monitoring. Overcoming challenges such as data scarcity and interpretability can optimize CNN utilization in glaucoma diagnosis. Measuring retinal nerve fiber layer thickness as a diagnostic marker proves valuable. CNN implementation reduces healthcare costs and improves access to quality eye care. Future research should focus on optimizing architectures and incorporating novel biomarkers. CNN integration in glaucoma detection revolutionizes ophthalmology, improving patient outcomes and access to care. This review paves the way for innovative CNN-based glaucoma detection methods. Abbreviations: CNN = Convolutional Neural Networks, AI = Artificial Intelligence, IOP = Intraocular Pressure, OCT = Optical Coherence Tomography, CLSO = Confocal Scanning Laser Ophthalmoscopy, AUC-ROC = Area Under the Receiver Operating Characteristic Curve, RNFL = Retinal Nerve Fiber Layer, RNN = Recurrent Neural Networks, VF = Visual Field, AP = Average Precision, MD = Mean Defect, sLV = square-root of Loss Variance, NN = Neural Network, WHO = World Health Organization.

International comparisons of intraocular pressures, as measured by Tono-Pen and Goldmann applanation tonometry, in healthy adults: A meta-analysis

BACKGROUND

Investigate intraocular pressure (IOP), as measured by Tono-Pen (TP) and Goldmann applanation tonometry (GAT), in healthy adults. Provide an updated synthesis of multinational, primary studies, reported during the 10-year period 2011 to 2021 and offer an evidence-based benchmark, against which IOP can be evaluated across subject variables and pathologies. Three primary research questions are investigated: Is there a statistically significant difference between IOP measured by TP and GAT? If yes, is the difference clinically significant? Is measurement of IOP affected by the country or setting location, in which the measurements are made?

METHODS

An aggregate meta-analysis was conducted on 22 primary studies, from 15 different countries. IOP measurements were made from each healthy adult subject, with both the TP and GAT. Primary studies were identified and data extracted according to recommended preferred reporting items for systematic reviews and meta-analysis protocol guidelines. Meta-analysis summary results are reported as the point estimate of the raw mean difference of IOP.

RESULTS

Meta-analysis reveals a statistically significant difference in raw mean differences in IOP, when measured by TP and GAT, in the healthy adult population. Tono-Pen IOP measurements are higher than GAT IOP measurements. The point estimate for the summary effect size = -0.73 mm Hg, P = .03. The prediction interval for the true effect size, in 95% of all comparable populations, is -4.03 to 2.58 mm Hg. There is no clinically significance difference in IOP when measured by TP and GAT. Meta-regression analysis reveals statistically significant differences in measurement of IOP by countries, R2 analog = 0.75, P = .001. There is no statistically significant difference in measurement of IOP as a function of measurement location setting, R2 analog = -0.17, P = .65.

CONCLUSIONS

IOP measured by TP are marginally higher compared to GAT, in the healthy adult population. However, from a clinical practice perspective, TP and GAT produce similar IOP measurements. There is evidence of significant variabilities in IOP measurements as a function of country. IOP measurements collected in a research laboratory setting are similar to IOP collected in a clinical setting. Results have implications for the primary care physician requiring a portable, inexpensive, reliable, and easily administered instrument to assess IOP.

Comparison of Intraocular Pressure Measurements With Goldmann Applanation Tonometry, Tonopen XL, and Pascal Dynamic Contour Tonometry in Patients With Descemet Membrane Endothelial Keratoplasty

PRCIS

IOP measured with Tonopen and DCT was higher than GAT in eyes that underwent DMEK.

PURPOSE/AIM OF THE STUDY

To compare intraocular pressure (IOP) measurements measured based on Goldmann applanation tonometry (GAT), Tonopen XL, and Pascal Dynamic Contour Tonometry (DCT) in patients who had undergone descemet membrane endothelial keratoplasty (DMEK) and to appraise the influence of central corneal thickness (CCT) on IOP measurements.

MATERIALS AND METHODS

Thirty-four eyes (from 34 patients) who underwent DMEK at least 1 month before the study were included. We performed Tonopen XL, GAT, and DCT IOP measurements at 10 min intervals. Bland-Altman plots were used to assess agreement between GAT, Tonopen XL, and DCT. Spearman rank correlation was used to calculate the deviation from GAT readings by each device and correlate the readings with the CCT variable.

RESULTS

The mean IOP values with GAT, Tonopen XL, and DCT were 14.9±5.8, 16.2±5.5, and 19.2±5.0, respectively. Statistically significant differences between GAT and Tonopen XL and between GAT and DCT were noted ( r =0.942 [0.885-0.971]; P =0.0001 and r =0.942 [0.885-0.971]; P =0.0001, respectively). DCT tended to return a higher IOP relative to GAT and Tonopen XL. CCT and IOP readings obtained by GAT, Tonopen XL, and DCT did not show a statistically significant correlation with each other.

CONCLUSION

IOP as measured with both Tonopen and DCT was found to be higher than GAT in eyes that underwent DMEK surgery although the techniques showed a good correlation. After DMEK surgery, all 3 measurement techniques can be practical in routine postoperative examinations, however it is recommended to measure IOP with the same device during patient follow-up.

Capsanthin from Capsicum annum fruits exerts anti-glaucoma, antioxidant, anti-inflammatory activity, and corneal pro-inflammatory cytokine gene expression in a benzalkonium chloride-induced rat dry eye model

Dry eye disease (DED) is a complex ocular surface inflammatory disease. Its occurrence varies widely over the world, ranging from 5% to 34%. The use of preservatives, specifically benzalkonium chloride, in the ocular drops worsens the DED conditions. Furthermore, the Covid-19 pandemic increased screen time and the use of face masks and shields. As a result, the number of people suffering from dry eye disease (DED) has increased significantly in recent years. The main objective of our study is to find a solution to manage the dry eye disease (DED) preferably from natural source without any adverse events. In this study, the beneficial effects of capsanthin from Capsicum annum (CCA) were evaluated on benzalkonium chloride (BAC)-induced dry eye disease (DED) in Albino Wistar rats. Oral supplementation of CCA resulted in a statistically significant decrease in intraocular pressure (IOP) (p < .0001), increase in tear break-up time (TBUT) (p < .01), decline in Schirmer test results (p < .01), and decrease in corneal surface inflammation (p < .01). Capsanthin ameliorated in reducing oxidative stress by increasing serum antioxidant levels such as glutathione peroxidase (GPX), nitric oxide (NO), and lactoferrin (LTF) and inhibiting matrix metalloproteinases 2 and 9 (MMP2 and MMP9) (p < .0001). Capsanthin treatment significantly inhibited the expression of inflammatory cytokines, tumor necrosis factor-alpha (TNF-α), interleukins (IL-2, IL-4, IL-6), and pro-inflammatory mediator, matrix metalloproteinase-9 (MMP9). Furthermore, the lacrimal gland expressed vascular cell adhesion molecule (VCAM-1), and prostaglandin-endoperoxide synthase 2 (PTGS2) was suppressed by CCA treatment. PRACTICAL APPLICATIONS: Benzalkonium chloride (BAC), a preservative widely used in the topical ocular drug delivery system (ODDS), causes undesirable effects such as dry eye disease as well as ameliorating intraocular pressure leading to optical nerve damage and irreversible vision loss. Capsanthin from Capsicum annum (CCA) can be used to treat symptoms related to dry eye disease such as inflammation, eye irritation, visual disturbance, ocular discomfort with potential damage to the ocular surface. The CCA may be beneficial in the treatment of glaucoma, an elevated intraocular pressure. Capsanthin from C. annum can be useful in managing DED by increasing tear break-up time (TBUT), declining in Schirmer test results and decreasing in corneal surface inflammation.

How to Measure Intraocular Pressure: An Updated Review of Various Tonometers

Intraocular pressure (IOP) is an important measurement that needs to be taken during ophthalmic examinations, especially in ocular hypertension subjects, glaucoma patients and in patients with risk factors for developing glaucoma. The gold standard technique in measuring IOP is still Goldmann applanation tonometry (GAT); however, this procedure requires local anesthetics, can be difficult in patients with scarce compliance, surgical patients and children, and is influenced by several corneal parameters. Numerous tonometers have been proposed in the past to address the problems related to GAT. The authors review the various devices currently in use for the measurement of intraocular pressure (IOP), highlighting the main advantages and limits of the various tools. The continuous monitoring of IOP, which is still under evaluation, will be an important step for a more complete and reliable management of patients affected by glaucoma.

Risk Factors for the Development of Ocular Hypertension After Keratoplasty: A Systematic Review

Supplemental Digital Content is Available in the Text.

To identify risk factors for the development of ocular hypertension after keratoplasty.

Patients' perception of glaucoma diagnosis practice: Results from a survey of glaucoma patients in North India

PURPOSE

This study assesses the practice patterns of diagnosing ophthalmologists, as reported by glaucoma patients attending specialty glaucoma clinics in urban and rural areas of North India, for a second opinion.

METHODS

Prospective cross-sectional study using a structured interview-based survey was conducted from 1 November 2011 to 31 October 2012 on patients attending two specialty glaucoma care facilities in North India. Both clinics were in North India; however, one was rural (Kaithal) and one was urban (Delhi). Patients were asked through descriptions of machines and processes, regarding practice patterns of their glaucoma diagnosing ophthalmologists. The interview was conducted by ophthalmic assistants in tune with the vernacular of the region, in a language understood by the interviewee.

RESULTS

A total of 1506 patients consented to participate in the survey. The majority of patients reported undergoing tests for intraocular pressure measurement; however, 56-60% of these tests were carried out by the non-contact tonometer. More than 90% of patients reported no knowledge regarding the type and severity of the glaucoma they suffered from, and even less reported undergoing gonioscopy (3.6% Karnal and 16% Delhi). 84-86% patients who underwent perimetry reported undergoing at least some digital imaging of the optic disc.

CONCLUSIONS

Better counselling of, and communication with, the patient would help increase their awareness regarding their condition and the care required. This has the potential to enable better compliance with and adherence to treatment. Standardized training of ophthalmologists to improve clinical diagnosis of glaucoma would also go a long way.

Impact of corneal parameters on intraocular pressure measurements in different tonometry methods

AIM

To evaluate the impact of central corneal thickness (CCT) and corneal curvature on intraocular pressure (IOP) measurements performed by three different tonometers.

METHODS

IOP in 132 healthy eyes of 66 participants was measured using three different tonometry techniques: Goldmann applanation tonometer (GAT), Pascal dynamic contour tonometer (DCT), and ICare rebound tonometer (RT). CCT and corneal curvature were assessed.

RESULTS

In healthy eyes, DCT presents significantly higher values of IOP than GAT (17.34±3.69 and 15.27±4.06 mm Hg, P<0.0001). RT measurements are significantly lower than GAT (13.56±4.33 mm Hg, P<0.0001). Compared with GAT, DCT presented on average 2.51 mm Hg higher values in eyes with CCT<600 µm and 0.99 mm Hg higher results in eyes with CCT≥600 µm. The RT results were lower on average by 1.61 and 1.95 mm Hg than those obtained by GAT, respectively. Positive correlations between CCT in eyes with CCT<600 µm were detected for all IOP measurement techniques, whereas a similar relationship was not observed in eyes with thicker corneas. A correlation between IOP values and keratometry in the group with CCT<600 µm was not detected with any of the tonometry methods. In thicker corneas, a positive correlation was found for GAT and mean keratometry values (R=0.369, P=0.005).

CONCLUSION

The same method should always be chosen for routine IOP control, and measurements obtained by different methods cannot be compared. All analysed tonometry methods are dependent on CCT; thus, CCT should be taken into consideration for both diagnostics and monitoring.