scholarly journals New avenues of preoperative evaluation before corneal refractive surgery during the COVID-19 pandemic

2021 ◽  
Vol 21 (2) ◽  
pp. 72-77
Author(s):  
S.N. Sakhnov ◽  
◽  
O.A. Klokova ◽  
A.V. Piskunov ◽  
R.O. Damashauskas ◽  
...  
Keyword(s):  
Refractive Surgery ◽  
Preoperative Evaluation ◽  
Corneal Thickness ◽  
Diagnostic System ◽  
Spherical Equivalent ◽  
Mean Values ◽  
Applanation Tonometer ◽  
Corneal Refractive Surgery ◽  
The Difference

Aim: to assess the reproducibility and comparability of measurements produced by Visionix VX130+ and their consistency with data produced by Topcon KR-800, NT-530P, Oculyzer, and RTVue-100. Patients and Methods: 124 patients (248 eyes) aged 18–45 years (mean age 25.24±7.5 years) were enrolled. Refractometry, IOP levels, and pachymetry measured by Visionix VX130+ system (LLC “Visionix Rus” — affiliated company of Luneau Technology Operations) were compared to the readings produced by Topcon KR-800 Auto Kerato-Refractometer (Topcon, Japan), Nidek NT-530P non-contact tonometer (Nidek, Japan), CT200 Goldman applanation tonometer (Reichert, USA), ALLEGRO Oculyzer (WaveLight AG, Germany), and RTVue-100 (Optovue, USA). Results: refractometry produced by Visionix VX130+ is highly reproducible and stable. Mean spread of spherical equivalent was 0.22±0.22 D and mean spread of cylindrical equivalent was 0.23±0.16 D. No significant differences were revealed between refractometry readings produced by Visionix VX130+ and Topcon KR-800 in patients with myopia (p>0.05). Both Visionix VX130+ and Nidek NT-530P (automated IOP measurements) produce two values, i.e., with and without corneal thickness. Our findings suggest that mean values are virtually similar in Visionix VX130+ group (p>0.05) while Nidek NT-530P produces significant differences (p<0.05). Mean central corneal thickness (CCT) measured by Visionix VX130+ was almost similar to CCT measured by Oculyzer (the difference was 3.8±2.23 μm, р>0.05) and greater than CCT measured by RTVue-100 (р<0.05). Conclusion: clinical trials comparing the readings produced by Visionix VX 130+ and other devices whose reliability was evidenced by long-term clinical experience have demonstrated that Visionix VX 130+ multifunctional diagnostic system is fully in line with the COVID-19 pandemic requirements. This device provides the measurements for performing safe and effective corneal refractive surgery for refractive errors. Keywords: corneal refractive procedure, pneumotonometry, aberrometry, corneal topography, pachymetry, cornea, intraocular pressure. For citation: Sakhnov S.N., Klokova O.A., Piskunov A.V. et al. New avenues of preoperative evaluation before corneal refractive surgery during the COVID-19 pandemic. Russian Journal of Clinical Ophthalmology. 2021;21(2):72–77. DOI: 10.32364/2311-7729-2021-21-2-72-77.

scholarly journals Effects of Warm Compress on Tear Film, Blink Pattern and Meibomian Gland Function in Dry Eyes After Corneal Refractive Surgery

2021 ◽  
Author(s):  
Xueyi Zhou ◽  
Yang Shen ◽  
Jianmin Shang ◽  
Xingtao Zhou
Keyword(s):  
Dry Eye ◽  
Refractive Surgery ◽  
Corneal Thickness ◽  
Tear Film ◽  
Meibomian Gland ◽  
Blink Rate ◽  
Lipid Layer ◽  
Mean Values ◽  
Corneal Refractive Surgery ◽  
Gland Function

Abstract Background To assess the effects of warm compress (WC) on tear film lipid layer, blink pattern and Meibomian gland function in patients with dry eye following femtosecond laser small incision lenticule extraction (SMILE) and laser-assisted subepithelial keratomileusis (LASEK). Methods We enrolled 37 eyes of 37 participants, each with dry eye for more than 2 years following SMILE (25 eyes) or LASEK (12 eyes). WC was performed using a spontaneously heating eye mask. Safety parameters and effectiveness parameters (tear film break-up time, TBUT; tear film lipid layer thickness, TFLLT; blink pattern, and Meibomian secretory function scores, MGS) were assessed before and after WC. Results After WC, the following mean values all increased relative to baselines: central corneal thickness, spherical equivalent, minimum (Min-), maximum (Max-) and average (Ave-) TFLLT, TBUT, total MGS (TMGS), number of glands secreting any liquid (MGL), and complete blink rate (CBR) (p values ranging from < 0.0001 to 0.042). Partial blink frequency (PBF) and partial blink rate (PBR) decreased (p = 0.002 in both cases). The decrease of PBF was higher in SMILE subgroup than in LASEK (p = 0.030). TBUT variation was positively correlated with that of Ave-TFLLT and TMGS (p = 0.046, 0.028, respectively). Max-TFLLT variation was correlated with that of TMGS (p = 0.020). Conclusions WC may temporarily improve tear film quality and blink pattern, augment Meibomian gland function, and relieve dry eye symptoms after corneal refractive surgery, particularly that using the SMILE technique.

scholarly journals Correlation between central corneal thickness and intraocular pressure in various age groups

2010 ◽  
Vol 138 (5-6) ◽  
pp. 279-286 ◽  
Author(s):  
Ivan Marjanovic ◽  
Djordje Kontic ◽  
Paraskeva Hentova-Sencanic ◽  
Vujica Markovic ◽  
Marija Bozic
Keyword(s):  
Intraocular Pressure ◽  
Refractive Surgery ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Age Groups ◽  
The Third ◽  
Significant Difference ◽  
Applanation Tonometer ◽  
Corneal Refractive Surgery ◽  
Piezoelectric Pressure Sensor

Introduction The Pascal Dynamic Contour Tonometer (DCT) is an ophthalmic investigational device which directly calculates the dynamic pulsatile fluctuations in intraocular pressure (IOP) using a piezoelectric pressure sensor embedded in the devices tip. Objective The aim of this study was to compare IOP results obtained with Goldmann applanation tonometer (GAT), and their correlation with central corneal thickness (CCT) in patients of various age groups. Methods We studied 37 patients (17 male and 20 female), divided into three age groups: younger than 40 years; 40-60 years old, and older than 60 years. In the first and second group there were patients rarely and in the third mostly diagnosed and medicamentously compensated glaucoma. In topical anesthesia, first we measured CCT, with ultrasound pachimeter, then IOP with DCT and GAT. Results Statistically significant difference between measurements of IOP with the DCT and GAT appeared in all groups: I mean diff. -1.71?}1.27 mm; p<0.0001; II mean diff. -1.19?}1.06 mm; p<0.0001; III mean diff. -1.69?}1.67 mm; p<0.0001. CCT was in indirect correlation with the values of IOP measured both with the DCT and GAT in the first and third, while it was in the direct correlation with these values in the second group. Conclusion CCT had no influence on IOP measurements both with the DCT and GAT in none of the groups. The DCT cannot replace GAT, but it is a reliable device for the measurement of IOP particularly in corneal deformations (keratoconus, after corneal refractive surgery, corneal scars, etc.). .

scholarly journals Correlation between Central Corneal Thickness and Degree of Myopia among Malaysian Patients Undergoing Laser Keratorefractive Surgery

2020 ◽  
pp. 52-58
Author(s):  
Sagili Chandrasekhara Reddy ◽  
Mohd Mansor Shariff ◽  
Aina Malindri Dasrilsyah
Keyword(s):  
Optical Coherence Tomography ◽  
Refractive Surgery ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Anterior Segment ◽  
Military Hospital ◽  
Moderate Degree ◽  
Optical Coherence ◽  
Corneal Refractive Surgery ◽  
The Mean

Purpose: To determine the central corneal thickness in myopic adult patients scheduled for laser corneal refractive surgery and to explore its correlation with degree of refractive error. Materials and Methods: The case records of 130 myopic patients who underwent laser corneal refractive surgery in a military hospital over a period of two years were reviewed to determine the central corneal thickness. All patients had 6/6 vision with best correction, and did not have any other anterior segment or fundus diseases in both eyes. The central corneal thickness was measured with Visante Carl Zeiss anterior segment optical coherence tomography instrument.                                                                                                                        Results: Out of 130 patients, males were more (73, 56.2%); mean age of patients was 33.8 years (range 18-60 years) and majority were Malays (110, 84.6%).  The spherical power of myopia ranged from – 0.5 to – 10.00 D, and the cylindrical power ranged from – 0.25 to – 3.25 D. The mean central corneal thickness of both eyes was 528.2 µm (range 331- 615 µm); in the mild degree of myopia (- 0.50 to - 2.00 D) 527.9 µm, moderate degree (- 2.25 to -5.00 D) 529.4 µm, and high degree (-5.25 to -11.00 D) 523.9 µm. Conclusion: The anterior segment optical coherence tomography provides noncontact, rapid, pachymetry mapping of the corneal thickness. In Malaysian patients, the mean central corneal thickness of both eyes in myopia was 528.1 µm (range 331- 615 µm). There was no correlation between the mean central corneal thickness and degree of myopia, different genders, age groups, ethnic groups and two eyes.

scholarly journals Comparison of intraocular pressure measured by ocular response analyzer and Goldmann applanation tonometer after corneal refractive surgery: a systematic review and meta-analysis

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Hui Zhang ◽  
Zhengtao Sun ◽  
Lin Li ◽  
Ran Sun ◽  
Haixia Zhang
Keyword(s):  
Intraocular Pressure ◽  
Subgroup Analysis ◽  
Refractive Surgery ◽  
Meta Analysis ◽  
Mean Difference ◽  
Ocular Response Analyzer ◽  
Cochrane Library ◽  
Goldmann Applanation Tonometer ◽  
Applanation Tonometer ◽  
Corneal Refractive Surgery

Abstract Background Accurate measurement of intraocular pressure (IOP) after corneal refractive surgery is of great significance to clinic, and comparisons among various IOP measuring instruments are not rare, but there is a lack of unified analysis. Although Goldmann Applanation Tonometer (GAT) is currently the internationally recognized gold standard for IOP measurement, its results are severely affected by central corneal thickness (CCT). Ocular Response Analyzer (ORA) takes certain biomechanical properties of cornea into account and is supposed to be less dependent of CCT. In this study, we conducted the meta-analysis to systematically assess the differences and similarities of IOP values measured by ORA and GAT in patients after corneal refractive surgery from the perspective of evidence-based medicine. Methods The authors searched electronic databases (MEDLINE, EMBASE, Web of science, Cochrane library and Chinese electronic databases of CNKI and Wanfang) from Jan. 2005 to Jan. 2019, studies describing IOP comparisons measured by GAT and ORA after corneal refractive surgery were included. Quality assessment, subgroup analysis, meta-regression analysis and publication bias analysis were applied in succession. Results Among the 273 literatures initially retrieved, 8 literatures (13 groups of data) with a total of 724 eyes were included in the meta-analysis, and all of which were English literatures. In the pooled analysis, the weighted mean difference (WMD) between IOPcc and IOPGAT was 2.67 mmHg (95% CI: 2.20~3.14 mmHg, p < 0.0001), the WMD between IOPg and IOPGAT was − 0.27 mmHg (95% CI: − 0.70~0.16 mmHg, p = 0.2174). In the subgroup analysis of postoperative IOPcc and IOPGAT, the heterogeneity among the data on surgical procedure was zero, while the heterogeneity of other subgroups was still more than 50%. The comparison of the mean difference of pre- and post-operative IOP (∆IOP) was: mean-∆IOPg > mean-∆IOPGAT > mean-∆IOPcc. Conclusions IOPcc, which is less dependent on CCT, may be more close to the true IOP after corneal refractive surgery compared with IOPg and IOPGAT, and the recovery of IOPcc after corneal surface refractive surgery may be more stable than that after lamellar refractive surgery.

Correlation between refractive state, corneal thickness, and keratometry in ametropic patients

2019 ◽  
Vol 30 (5) ◽  
pp. 891-896
Author(s):  
Amir Rosenblatt ◽  
Michael Mimouni ◽  
Tzahi Sela ◽  
Gur Munzer ◽  
David Varssano ◽  
...  
Keyword(s):  
Retrospective Analysis ◽  
Refractive Error ◽  
Refractive Surgery ◽  
Corneal Thickness ◽  
Spherical Equivalent ◽  
Moderate Correlation ◽  
Male And Female ◽  
Tel Aviv ◽  
Refractive State ◽  
Patient Demographics

Purpose: To analyze the correlation between age, gender, refractive error, keratometry, and corneal thickness in a large group of subjects. Methods: This study is a retrospective analysis of patients who underwent refractive surgery between January 2000 and February 2015 at Care Vision Refractive Clinic, Tel Aviv, Israel. Patient demographics, subjective refraction, pachymetry, and average keratometry were collected. Results: Overall, 51,113 eyes of patients averaging 28.8 ± 9.3 years of which 53.9% were males were included. Average keratometry, spherical equivalent and cylindrical error differed significantly between male and female subjects (p < 0.001), while pachymetry did not (p = 0.332). In myopic eyes, correlations between age, pachymetry, average keratometry, spherical equivalent, and cylindrical error were all statistically significant except for the correlation between age and either pachymetry (p = 0.462) or spherical equivalent (p = 0.016). All correlations found were negligible or small (|r|= 0.003 to 0.141). In hyperopic eyes, correlations between age, pachymetry, average keratometry, spherical equivalent, and cylindrical error were all statistically significant except for the correlation between average keratometry and either pachymetry or cylindrical error (p = 0.344 or p = 0.274, respectively). All correlations found were negligible or small, except for a moderate correlation found between age and cylindrical error (r = 0.365). Conclusion: Refractive state, pachymetry, and keratometry of refractive surgery candidates are mostly weakly correlated.

scholarly journals Comparison of Intraocular Pressure before and after Laser In Situ Keratomileusis Refractive Surgery Measured with Perkins Tonometry, Noncontact Tonometry, and Transpalpebral Tonometry

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Isabel Cacho ◽  
Juan Sanchez-Naves ◽  
Laura Batres ◽  
Jesús Pintor ◽  
Gonzalo Carracedo
Keyword(s):  
Intraocular Pressure ◽  
Refractive Surgery ◽  
Corneal Thickness ◽  
Laser In Situ Keratomileusis ◽  
Spherical Equivalent ◽  
Transpalpebral Tonometry ◽  
Spherical Equivalent Refraction ◽  
Before And After ◽  
Noncontact Tonometry

Purpose. To compare the intraocular pressure (IOP) before and after Laser In Situ Keratomileusis (LASIK), measured by Diaton, Perkins, and noncontact air pulse tonometers.Methods. Fifty-seven patients with a mean age of 34.88 were scheduled for myopia LASIK treatment. Spherical equivalent refraction (SER), corneal curvature (K), and central corneal thickness (CCT) and superior corneal thickness (SCT) were obtained before and after LASIK surgery. IOP values before and after surgery were measured using Diaton, Perkins, and noncontact air pulse tonometers.Results. The IOP values before and after LASIK surgery using Perkins tonometer and air tonometers were statistically significant (p<0.05). However, no significant differences were found (p>0.05) for IOP values measured with Diaton tonometer. CCT decreases significantly after surgery (p<0.05) but no statistical differences were found in SCT (p=0.08). Correlations between pre- and postsurgery were found for all tonometers used, withp=0.001andr=0.434for the air pulse tonometer,p=0.008andr=0.355for Perkins, andp<0.001andr=0.637for Diaton.Conclusion. Transpalpebral tonometry may be useful for measuring postsurgery IOP after myopic LASIK ablation because this technique is not influenced by the treatment.

scholarly journals Reversal of Myopic Correction for Patients Intolerant to LASIK

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Amr A. Gab-Alla
Keyword(s):  
Refractive Surgery ◽  
Average Duration ◽  
Corneal Thickness ◽  
Case Series ◽  
Spherical Equivalent ◽  
Efficacy And Safety ◽  
Effective Option ◽  
Optical Zone ◽  
The Mean ◽  
One Year

Purpose. To evaluate the outcome of the reversal of myopia correction in patients intolerant to LASIK. Methods. This study is a retrospective and case series of patients who decided to reverse their previous myopic LASIK correction between July 2012 and July 2020. It was conducted at a private refractive surgery centre, Ismailia, Egypt. The patients were followed up after reversal treatment for one year. Primary LASIK and reversal treatment were performed by a 500 kHz Amaris excimer laser platform. The main outcomes included refractive predictability, stability, efficacy, and safety and any reported complications. Results. This study included 48 eyes of 24 patients (6 male and 18 female patients). The average duration between the primary LASIK surgery and reversal treatment was 3.20 ± 0.30 months (range 3 to 4 months). Reversal treatment was bilateral in all patients. The mean age of the patients was 38 ± 1.9 years (range 37 to 45 yrs). After reversal, the mean postreversal cycloplegic refraction spherical equivalent was −1.82 ± 0.34 D (range −1.50 to −3.00 D). The mean ablation depth was 34.10 ± 7.36 μm (range 20 to 46 μm), and the mean of the central corneal thickness 12 months after reversal treatment was 510.2 ± 14.4 μm (range 515 to 487 μm). The mean keratometric reading was 42.6 ± 1.6 (range 42.5 to 44.8). The mean of CDVA was 0.2 ± 0.03 log MAR (range −0.10 to 0.4 log MAR). The mean optical zone of reversal treatment was 6.1 ± 0.3 mm (range 5.9 to 6.2 mm). UDVA was 0.4 log MAR in 87.5% of the patients, 0.5 log MAR in 8.3% of the patients, and 0.6 log MAR in 4.2% of the patients. CDVA remained unchanged in 83.3% of patients; 2.1% of the patients gained one line of CDVA (Snellen); 8.3% of the patients lost one line of CDVA; 6.3% of the patients lost two lines of CDVA. No cases of corneal ectasia were recorded. The only postoperative complications were flap microfolds in 3 eyes (6.25%). Conclusion. In conclusion, this study demonstrates that reversal of myopic LASIK treatment is a safe, stable, and effective option for intolerant patients.

Photometric results of the long-term monitoring of the active asteroid (596) Scheila

2020 ◽  
Author(s):  
Zhong-Yi Lin ◽  
Chen-Yen Hsu
Keyword(s):  
Light Curve ◽  
Rotation Period ◽  
Impact Event ◽  
Mean Values ◽  
Photometric Observations ◽  
The Mean ◽  
The Difference ◽  
The Impact ◽  
Term Monitoring

&lt;p&gt;(596) Scheila was observed to have an active appearance as a result of impact event in late 2010. In additional the coma feature, the shape of light curve had been found the difference probably fresh material or surface properties changed around the impact site. In this study, we present the results of our monitoring observations obtained in 2014 and 2019-2020. The mean values of the color indices (B&amp;#8722;V&amp;#160;= (0.75 &amp;#177; 0.08)&lt;sup&gt;m&lt;/sup&gt;,&amp;#160;V&amp;#8722;R&amp;#160;= (0.45 &amp;#177; 0.04)&lt;sup&gt;m&lt;/sup&gt;, and&amp;#160;R&amp;#8722;I&amp;#160;= (0.44 &amp;#177; 0.09)&lt;sup&gt;m&lt;/sup&gt;) agree well with the values for asteroids of the D-types. The rotation period of the asteroid estimated from photometric observations in 2014 is 15.8 &amp;#177; 0.1 h.&amp;#160;The shape of the light curve is similar as that found after impact event. Furthermore, we did not find any rotational color variability in B-V, V-R and R-I diagrams, meaning the observed surface in this observing period of 2019-2020 is homogeneous.&lt;/p&gt;

scholarly journals Outcomes of MyoRing Implantation in Eyes with Keratoconus in the Eastern Province of Saudi Arabia: “A Single-Arm Cohort Study”

2019 ◽  
Vol 2019 ◽  
pp. 1-4
Author(s):  
Yousef Saad Alshammari ◽  
Abdulaziz Ismail Al Somali
Keyword(s):  
Visual Acuity ◽  
Saudi Arabia ◽  
Cohort Study ◽  
Corneal Thickness ◽  
Rank Test ◽  
Spherical Equivalent ◽  
Eastern Province ◽  
Historical Cohort ◽  
Signed Rank Test ◽  
The Difference

Purpose. To evaluate the efficacy and safety of MyoRing implantation in eyes with keratoconus managed at a tertiary eye hospital in the Eastern Province of Saudi Arabia. Methods. This one-armed historical cohort study included keratoconus patients operated for MyoRing implant. The cases were assessed before and 6 months after surgery. Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), spherical equivalent (SE), central corneal thickness (CCT), and corneal curvature (Kmean) were noted and measured before and 6 months after the intervention. Intra- and postoperative complications were noted. Result. We studied 12 eyes of 12 patients with moderate keratoconus. The median of Kmean was 50.6 mm (IQR 47.54; 52.5) and 44.5 mm (IQR 42.5; 46.8) before and 6 months after surgery. The change in Kmean was significant (P=0.002). The median spherical equivalent (SE) was −5.1D (interquartile range (IQR) 7.1; −3.6) and −0.6 (IQR −2.1; 0.8) before and 6 months after surgery. The difference in SE was significant (Wilcoxon signed-rank test P=0.004). The CCT was 447 ± 34 μm and 444 ± 30 μm before and 6 months after surgery, respectively. The CCT change was not significant (P=0.26). The UCVA and BCVA improved by 2 or more lines in 9 (75%) eyes, remained stable in 2 (16.7%) eyes, and decreased in 2 (16.7%) eyes. Conclusion. MyoRing implant seems to be a safe and effective procedure to manage low and moderate keratoconus. The outcomes could be further enhanced by additional procedures such as collagen cross-linkage and photorefractive keratectomy if warranted.

Icare versus Goldmann in a randomised middle-aged population

2020 ◽  
pp. 112067212092138
Author(s):  
Katri Stoor ◽  
Elina Karvonen ◽  
Pasi Ohtonen ◽  
M Johanna Liinamaa ◽  
Ville Saarela
Keyword(s):  
Intraocular Pressure ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Population Based ◽  
Rebound Tonometer ◽  
Goldmann Applanation Tonometer ◽  
Applanation Tonometer ◽  
Screening Study ◽  
The Difference

Purpose The aim of this study was to compare the measurements of intraocular pressure by two tonometers, the Icare rebound tonometer and the Goldmann applanation tonometer, in a randomised screening study. The influence of refraction and central corneal thickness on the measurements was also evaluated. Methods Intraocular pressure was measured with rebound tonometer and Goldmann applanation tonometer in 1266 participants; refraction and central corneal thickness were also determined. One randomised eye of each participant was selected for this report’s analysis. A Bland–Altman plot was used to compare the values obtained with the two devices. Results The correlation between rebound tonometer and Goldmann applanation tonometer was good: the intraclass correlation coefficient (r) between the two methods was 0.735 ( p < 0.001). The mean difference (rebound tonometer–Goldmann applanation tonometer) was 0.11 ± 2.3 mmHg. The difference was not statistically significant (95% confidence interval: 0.11 to 0.13, p = 0.09). With increasing central corneal thickness, not only did intraocular pressure values with both devices increase, but the difference between them also increased. Refraction (spherical equivalent) did not influence intraocular pressure or the rebound tonometer–Goldmann applanation tonometer difference. However, high astigmatism (≥2D) exerted an influence on intraocular pressure values taken with Goldmann applanation tonometer. Conclusion Measurements with rebound tonometer and Goldmann applanation tonometer are relatively uniform although rebound tonometer slightly overestimated intraocular pressure. Both rebound tonometer and Goldmann applanation tonometer and the difference between these devices were affected by central corneal thickness but not by refraction. Higher astigmatism affected Goldmann applanation tonometer more than rebound tonometer. It is concluded that rebound tonometer is a reliable method for measuring intraocular pressure in a population-based screening study.

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