Noncontact Air-puff Tonometry Research Articles

Safety of intraocular pressure measurement using air-puff tonometer after implantable collamer lens implantation

To determine the safety of intraocular pressure (IOP) measurement using a noncontact tonometer in patients who have undergone implantable collamer lens (ICL) implantation. Eye, Ear, Nose, and Throat Hospital. Prospective study. 64 eyes of 33 patients (aged 28.4 ± 5.2 years) scheduled for ICL implantation were enrolled. The anterior segment parameters and vault were obtained using an anterior segment analyzer. A noncontact air-puff tonometer was used preoperatively and at 1 day and 1 week postoperatively to assess corneal biomechanical properties and IOP. The Corvis ST was used to evaluate the distance between the corneal endothelial layer and iris (E-Iris Dist) and the distance between the corneal endothelial layer and ICL (E-ICL Dist) when the cornea was deformed by the airflow. The mean anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA) decreased significantly postoperatively (all P values <.001). The E-ICL Dist values measured 1 day and 1 week postoperatively were similar ( P = .107). However, a contact between the corneal endothelium and ICL was detected in 2 eyes when the cornea was deformed to the highest concavity. The 1-day postoperative vault, ACV, ACA, and preoperative stress-strain index contributed significantly ( P = .001, P = .023, P = .010, and P = .019, respectively) to determine the distance. The mean E-iris Dist values decreased significantly at 1 day and 1 week postoperatively ( P < .001). The 1-week postoperative vault and ACD contributed significantly ( P = .025 and P = .039, respectively) to determine the E-Iris Dist value. Excessively high vault, shallow ACD, narrow ACA, low ACV, and soft cornea are associated with a lower E-ICL distance and thus may be risk factors for a contact between the corneal endothelium and ICL during IOP measurement. Although there is no proof that the contact may cause any risks to the endothelium, noncontact air-puff tonometry should be avoided in eyes predicted by the study model to be at risk of this occurring. Contact IOP measurements using Goldmann applanation tonometers or dynamic contour tonometers may be alternate methods of IOP measurements in extreme cases.

Comparison of Intraocular Pressure Measurement by Goldmann Applanation Tonometer and Non-Contact Airpuff Tonometer

Purpose: To compare between the intra-ocular pressure (IOP) measured by Goldmann applanation tonometer (GAT) and non-contact air-puff tonometer (APT) considering GAT as gold standard. Study Design: Comparative analytical study Place and Duration of Study: Al-Shifa trust eye Hospital, Rawalpindi from January 2018 to June 2018 Methods: Five hundred individuals, 223 glaucoma patients and 277 non glaucoma control subjects were recruited. After taking a detailed history, slit-lamp examination and fundoscopy was performed to check glaucoma status of the eyes. Retinal nerve fiber layer (RNFL) was checked with optical coherence tomography. Non-contact air-puff tonometry of both eyes were performed. Using a drop of local anesthetic and small amount of fluorescein, intra-ocular pressure was measured with GAT (Haag Streit Diagnostics).Central corneal thickness was measured for correction of IOP measurement with GAT. Paired sample correlations were performed to compare the mean IOP with APT and GAT with and without correction factor. Sensitivity and specificity for measurement of IOP by APT was calculated considering GAT as gold standard. Results: Mean age of the male and female participants was 49.87+18.70years and 45.53+16.91years respectively. Mean IOP in glaucomatous eyes measured by GAT (after applying correction factor) and APT was 16.01+5.57 mmHg and 17.31+7.22 mmHg respectively. The sensitivity and specificity of APT for measuring IOP in glaucomatous eyes were 84.04% and 73.53% respectively. Conclusion: Non-contact air-puff tonometer has good sensitivity and specificity and can be used reliably for measurement of IOP in out-patient department and for mass screening of the population.

The Impact of Noncontact Tonometry and Icare Rebound Tonometry on Tear Stability and Dry Eye Clinical Practice.

The purpose of this study was to investigate the possible effects of the noncontact air puff tonometry (NCT) and Icare rebound tonometry (ICT) on the tear film stability by using the tear stability analysis system (TSAS) and dry eye parameters. Fifteen eyes from fifteen normal healthy subjects were investigated in this study. All subjects underwent TSAS surface regularity index (SRI) examinations, TBUT, and IOP measurements. The mean IOP results measured with NCT were 13.3 ± 1.86 mm Hg, and the mean IOP results measured with ICT were 15.88 ± 3.09 mm Hg (p > 0.05). The mean values of baseline, 5 min, and 10 min of the NCT-SRI and ICR-SRI were tested. There were statistically significant differences between NCT-Baseline SRI, NCT-5 min SRI, and NCT-10 min SRI values (p < 0.05). SRI values significantly increased after NCT. The mean values of the baseline, 5 min, and 10 min of the ICT-SRI were also assessed. There were no statistically significant differences between ICT-Baseline SRI, ICT-5 min SRI, and ICT-10 min SRI values (p > 0.05). The mean TBUT values exhibited a significant decrease at 1 min, 5 min, and 10 min compared with baseline values for the NCT and ICT (p < 0.01). NCT-TBUT and ICT-TBUT values were also compared with each other in the same time period. There were no statistically significant differences between NCT-Baseline and ICT-Baseline TBUT values (p > 0.05). In conclusion, intraocular pressure measurements in routine ophthalmology clinical practices by either NCT or ICT cause deterioration in the tear film stability which might affect tear stability testing when performed soon after IOP measurements. It is best to wait at least for 20–30 min after the IOP measurement before evaluating the tear film and the corneal surface or perform tonometry after the tear film-ocular surface evaluation tests.

Comparaison de la tonomérie de Goldmann à la tonométrie à air pulsé à propos de 159 patients à Abidjan

The goal of this study was to compare the intraocular pressure (IOP) values obtained with each of the tonometry methods as well as to study the effect of corneal pachymetry on the measurements obtained by each method. We carried out a cross-sectional, descriptive, analytical, prospective study in the ophthalmology department of a multispecialty clinic in Abidjan (Ivory Coast) from April 2018 to August 2018. Patients aged 15 and over were included in the study. Over this period, IOP was measured by Goldman Applanation Tonometer (HaagStreit, AT 900, Switzerland) and air-puff Tonopachymeter (Nidek, NT 530 P, Japan), which also permitted measurement of central optical corneal pachymetry. The data analyzed focused on socio-demographic characteristics, ophthalmologic history, tonometry, and central corneal pachymetry. The comparison of the values obtained by both devices and the effect of central corneal thickness (CCT) on tonometry were analyzed using EpiDataAnalysis V2.2.2.183 software. We examined 318 eyes of 159 patients whose mean age was 40±12.57 years, range 16 to 82 years. The gender ratio was 1. A past ophthalmologic history was noted in 79.2% of patients. The mean IOP by Goldmann applanation tonometry was 12.75±3.17mmHg, and that by non-contact air-puff tonometry was 13.83±3.80mmHg. The mean central corneal thickness was 530.50±32.61μm. The difference between IOP measured by non-contact tonometry and that measured by contact tonometry was statistically significant, with P=0.00. There was no statistically significant relationship between central corneal pachymetry and contact tonometry (P=0.80). However, there was a statistically significant relationship between non-contact tonometry and central pachymetry (P=0.00). The values obtained with the air-puff tonometer are more affected by central corneal thickness. The values obtained by Goldmann applanation tonometry are not equivalent to those obtained by non-contact air-puff tonopachymetry.

A simple way to minimize cross infection from tear droplets during noncontact air-puff tonometry

A simple way to minimize cross infection from tear droplets during noncontact air-puff tonometry

Aerosol formation during non-contact "air-puff"tonometry and its significance for prevention of COVID-19

Objective To evaluate the aerosol and concentration (PM2.5, PM10 and aerosol particle number) formation in non-contact air-puff tonometry and provide suggestions for medical workers to take appropriate daily protection during the prevalence of 2019-nCoV. Methods A cross-sectional study was carried out in this study.Thirty healthy subjects were enrolled on February 22, 2020 in Eye Hospital of Wenzhou Medical University.The intraocular pressure (IOP) was measured by non-contact air-puff tonometer in the ophthalmic consulting room and the hall with or without masks.Particulate matter (PM)2.5, PM10 and aerosol particles were recorded by air quality detector.The cumulative effects of IOP measurement, PM2.5, PM10 and aerosol particle number were analyzed, and the aerosol density of subjects with and without masks was compared. Results The PM2.5, PM10 and aerosol particles produced by the non-contact air-puff tonometry and increased with the increase of spray times.The IOP curves of 60 eyes of 30 subjects were measured respectively in two environments of medical consulting room and medical institution hall.It was found that PM2.5, PM10 and particle number fluctuated and increased with the increase of IOP measurement person times, showing cumulative effect, and the accumulation speed of aerosol density in hall was faster than that in consulting room.The density of PM2.5 and PM10 produced without gauze mask were (53.417±2.306) and (85.350± 3.488) μg/m3, which were higher than those of (50.567±0.862) and (80.617±1.463) μg/m3 with gauze mask.The differences were statistically significant (P=0.028, 0.019), and significant difference was found in aerosol density between with and without gauze mask, although more aerosol was produced without gauze mask in comparison to gauze mask (P=0.123). Conclusions Aerosol can be produced by non-contact air-puff tonometer spraying, and it fluctuates with the increase of spraying times, showing a cumulative effect.The aerosol and particulate matter accumulation is higher in the hall with insufficient air circulation, and more aerosol and PM can be produced without gauze mask. Key words: Tonometer, non-contact air-puff; Aerosol; Particulate matter; Infection; Transmission; Corona virus disease-19

Comparison of rebound tonometry and non-contact airpuff tonometry to Goldmann applanation tonometry.

Purpose:The aim of this study was to compare the intraocular pressure measurements obtained from healthy subjects with the rebound tonometry, non-contact airpuff tonometry, and Goldmann applanation tonometry in different age groups.Methods:A total of 180 eyes of 90 healthy subjects were included in the study. According to the subjects’ ages, the eyes were categorized into three groups: group 1 (age: 7–17 years), group 2 (age: 18–40 years), and group 3 (age: 41–75 years). Intraocular pressure was measured on each subject always in the same order: rebound tonometry, non-contact airpuff tonometry, and Goldmann applanation tonometry. Central corneal thickness values were obtained using ultrasonic pachymetry. One-way repeated-measures analysis of variance, Pearson’s correlation coefficient, and Bland–Altman analysis were used for the statistical assessment.Results:The mean corneal thickness was found to be 604 ± 13 µm, 546 ± 15 µm, and 547 ± 15 µm in group 1, group 2, and group 3, respectively. Non-contact airpuff tonometry was significantly higher than both Goldmann applanation tonometry and rebound tonometry measurements in all groups (p < 0.001, for all). No statistical difference between Goldmann applanation tonometry and rebound tonometry measurements was found in group 1 (p = 0.248), group 2 (p = 0.63), and group 3 (p = 0.126). There was a significant positive correlation in the meaning of intraocular pressure measurements between rebound tonometry and non-contact airpuff tonometry; non-contact airpuff tonometry and Goldmann applanation tonometry; and Goldmann applanation tonometry and rebound tonometry in all groups.Conclusion:As a result, without need for topical anesthesia, fast measurement and ease-of-use rebound tonometry is a reliable alternative to Goldmann applanation tonometry in different age groups.

Central Corneal Thickness and Intraocular Pressure in Malay Children

BackgroundTo determine the mean values for central corneal thickness (CCT) and intraocular pressure (IOP) and the relationship between these values, in healthy Malay children to serve as reference values in diagnosis and treatment.DesignA cross-sectional study.Methodology/Principal FindingsOne hundred and eight eyes (54 subjects) of Malay children without diagnosis of ocular abnormality or disease meeting our inclusion and exclusion criteria were selected. The CCT and IOP were measured by specular microscopy and non-contact air-puff tonometry respectively, for analysis and comparison with the values obtained in previous studies. Mean CCT and IOP was found to be 530.87±30.79 µm and 15.65±3.05 mm Hg respectively. CCT was found not to vary with age. A positive relationship was found between CCT and IOP; specifically, with every 100-µm increase in CCT, IOP increased by 3.5 mm Hg.Conclusions/SignificanceCCT and IOP are strongly related in healthy Malay children aged 8 to 16. The mean CCT of Malay children is lower than that of majority children of other ethnic groups, supporting the existence of CCT variation among different populations and that ethnicity should be a key consideration when applying CCT data to the general pediatric population.

Diurnal Intraocular Pressure Fluctuation and Associated Risk Factors in Eyes with Angle Closure

To investigate diurnal intraocular pressure (IOP) fluctuation in eyes with angle closure in comparison with normal subjects and to look for associated risk factors for IOP fluctuation. Prospective, cross-sectional study. Ninety-eight eyes of 98 Asian subjects with angle closure (consisting of 32 primary angle-closure suspects [PACS], 34 subjects with primary angle closure [PAC], and 32 subjects with primary angle-closure glaucoma [PACG]) and 21 eyes of 21 normal control subjects. All angle-closure subjects were enrolled after laser peripheral iridotomy but before commencement of any medical or surgical treatment. Ophthalmic examination, including dynamic gonioscopy and automated perimetry, were performed, and diurnal IOP measurements were obtained using noncontact air-puff tonometry at hourly intervals between 8:00 am and 5:00 pm. Mean diurnal IOP, peak diurnal IOP, trough IOP, and IOP fluctuation (peak IOP-trough IOP) were compared between groups. Multiple linear regression analysis was performed to study the association of IOP fluctuation with clinical variables such as age, extent of peripheral anterior synechiae (PAS), central corneal thickness, vertical cup-to-disc ratio, and pattern standard deviation (PSD) on automated perimetry. Mean diurnal IOP, peak IOP, and IOP fluctuation. Most subjects were Chinese (89.1%) and female (61.3%). Intraocular pressure fluctuation was significantly higher in PACG (5.4+/-2.4 mmHg) and PAC (4.5+/-2.3 mmHg) subjects compared with PACS subjects (3.7+/-1.2 mmHg) and normal controls (3.8+/-1.1 mmHg; P = 0.005), with highest IOP found in the early morning. The combined PACG and PAC group had more than twice the risk (odds ratio, 2.38; 95% confidence interval, 1.1-5.1; P = 0.025) of having IOP fluctuation of more than 3 mmHg compared with the combined PACS and normal group. Extent of PAS (Pearson's correlation coefficient, r = 0.37; P = 0.0001) and visual field PSD (r = 0.34; P = 0.0002) were found to be associated with greater IOP fluctuation. The PACG and PAC eyes showed diurnal IOP fluctuation of 4 to 5 mmHg, and this fluctuation was higher than in PACS subjects and normal controls. The degree of PAS and visual field loss were associated with IOP fluctuation in PAC and PACG eyes.

Is Routine Pupil Dilation Safe among Asian Patients with Diabetes?

To investigate the risk of acute angle closure (AAC), changes in intraocular pressure (IOP), and factors associated with these outcomes after routine pupil dilation in a cohort of Asian subjects with diabetes mellitus. The study was a prospective observational case series of 1910 consecutive Asian subjects newly referred for assessment of diabetic retinopathy at a tertiary clinic. All subjects underwent routine pupil dilation unless there was a prior history of angle-closure glaucoma. Noncontact air-puff tonometry was used to assess IOP, which was measured by the same observer before and 1 hour after pupil dilation. Subjects were assessed for signs and symptoms of AAC before leaving the clinic, and their charts were also subsequently reviewed for revisits with AAC. Of the 1910 subjects who participated, none developed AAC. Sixty-nine subjects (3.6%, 95% CI: 2.8%-4.5%) showed an increase in IOP of >or=5 mm Hg in the either eye, 37 subjects (1.9%, 95% CI: 1.4%-2.6%) had a postdilation IOP >25 mm Hg in either eye, and only 10 subjects (0.52%, 95% CI: 0.25%-0.96%) had an increase in IOP >or=5 mm Hg and had a postdilation IOP >25 mm Hg in either eye. The level of predilation IOP and a known history of glaucoma were significant risk factors for a postdilation IOP >or=25 mm Hg. In this cohort of Asian persons with diabetes, the risk of AAC was insignificant after routine dilation of pupils for fundus examination. These data substantiate the safety of routine dilation of pupils in Asian patients with diabetes.

A Predictive Model for Postoperative Intraocular Pressure Among Patients Undergoing Laser in Situ Keratomileusis (LASIK)

The aim of this study was to develop a predictive model based on preoperative variables for estimating postoperative intraocular pressure (IOP) of those eyes undergoing LASIK surgery, to predict the amount of underestimated IOP after LASIK for myopia and myopic astigmatism. Pretest-post-test longitudinal study. Both eyes of 193 eligible subjects who underwent LASIK procedures at the Department of Ophthalmology, National Taiwan University Hospital, from July 2000 to December 2002 for myopia and myopic astigmatism were identified to build up the predictive models. IOPs were measured with noncontact air-puff tonometry. Information on age, gender, preoperative central corneal thickness (CCT), preoperative central corneal curvature (CCK), preoperative spherical equivalent refractive error, and ablation depth was collected and applied for predicting postoperative IOP after LASIK based on linear mixed model. Significant predictors for postoperative IOP after myopic LASIK procedures included age, gender, preoperative IOP, ablation depth, preoperative CCT, and preoperative spherical equivalent refractive errors. The linear mixed model, taking into account these significant preoperative correlates and the correlation of IOPs between both eyes of the same patient, explained 91% of the variation of postoperative IOP. A statistical model was developed for predicting the amount of underestimated IOP after LASIK for myopia and myopic astigmatism, which is of clinical importance to uncover ocular hypertension among patients whose information on postoperative IOP immediately after LASIK is not available.

Change in Intraocular Pressure in Myopic Eyes Measured With Contact and Non-contact Tonometers After Laser in situ Keratomileusis

To study the change in the intraocular pressure (IOP) after laser in situ keratomileusis (LASIK) for correction of myopia. One hundred twenty consecutive myopic eyes (60 patients) were included in a prospective study. All eyes received LASIK with the Nidek EC-5000 excimer laser and the Chiron Automated Corneal Shaper. Baseline refraction, keratometry, pachymetry, ablation depth, and IOP measured by Goldmann applanation tonometry and non-contact air puff tonometry were correlated with the IOP change after surgery. Sixty healthy eyes of 30 subjects served as controls. At 6 months, 108 eyes (90%) were examined. Compared to preoperative values, IOP decreased in 103 eyes (95.4%) when measured with applanation tonometry; it decreased in all eyes when measured with air puff tonometry. Mean change in IOP was -4.3 +/- 2.1 mmHg (range, -10.0 to +1.0 mmHg) with the applanation and -6.1 +/- 2.3 mmHg (range, -12.0 to -1.0 mmHg) with air puff tonometry. The IOP change measured with either instrument correlated significantly with the baseline IOP (P < .001) and the ablation depth (air puff, P < .001, applanation; P = .006). Intraocular pressure decreased significantly after LASIK when measured with either Goldmann (mean 4.3 mmHg) or air puff (mean 6.1 mmHg) tonometers. This decrease may delay the diagnosis or affect the management of future glaucoma that may develop in a myopic eye that received LASIK.