Central Corneal Thickness Measurements Research Articles

An Evaluation of Central Corneal Epithelial Thickness and Central Corneal Thickness Determined On Optic Coherence Tomography Before and After Applanation Tonometry

Objective: To determine the changes in corneal epithelial thickness and central corneal thickness using optic coherence tomography taken after Goldmann applanation tonometry measurements. Material and Methods: The study included 25 patients who presented at our clinic for routine ophthalmological examination. Before taking tonometry measurements of the patients, epithelial corneal thickness and central corneal thickness values were determined using optic cohence tomography (OCT). The intraocular pressure (IOP) was measured with tonometry and then the corneal OCT measurements were repeated. All the OCT and tonometry measurements were taken by the same clinician. Results: Evaluation was made of 25 patients comprising 18 males and 7 females with a mean age of 36.6 years (range, 17-55 years). The mean epithelial corneal thickness was 52.58 microns before the applanation tonometry measurement, and 52.02 microns after the tonometry (p=0.059). Central corneal thickness was measured as mean 530.96 microns before tonometry and 529.88 microns after (p>0.05). No statistically significant difference was determined in the changes of both measurements. Following tonometry, a change was seen in corneal epithelial thickness, but not of a statistically significant level (p=0.059). Conclusion: The study results showed no statistically significant difference in the measurements of corneal epithelial thickness and central corneal thickness following applanation tonometry. Although not statistically significant, the difference seen in thickness indicates desquamation in the epithelial cells as a result of the procedure. This may cause complaints such as a reduction in visual acuity and the feeling of burning or pricking in the eye. If glasses are to be prescribed for patients, this should be taken into consideration and the examination should be made before the tonometry measurement. To the best of our knowledge, there has been no previous study in literature of central corneal epithelial thickness measured before and after tonometry, and therefore the results obtained in this study are the first on this subject.

Evaluation of Corvis ST tonometer with the updated software in glaucoma practice.

To evaluate the agreement of biomechanically corrected intraocular pressure (b-IOP) and central corneal thickness (CCT) measurements obtained with the updated Corvis ST tonometer versus Goldmann applanation tonometry (GAT) and optical-based corneal pachymetry (OB-CCT) in controls, patients with ocular hypertension (OHT) and primary open angle glaucoma (POAG). Additionally, we examined the differences in corneal deformation parameters provided by the updated Corvis ST among the three groups. For each participant, GAT IOP, OB-CCT and measurements with a Corvis ST with updated software were obtained. Bland-Altman analysis was used to assess the agreement between the two measurement methods. A consecutive series of 80 eyes from 80 participants (30 with POAG, 25 with OHT and 25 normal controls) were included in this prospective study. The mean GAT IOP of all eyes was 17.2±3.6 mm Hg, and the mean b-IOP was 15.9±3.7 mm Hg (Spearman's rho=0.767, P<0.001). The 95% limits of agreement (LoAs) ranged from -3.1 mm Hg to 5.5 mm Hg for GAT IOP and b-IOP. b-IOP was not correlated with OB-CCT (Spearman's rho=-0.13 P=0.917). Meanwhile there was a weak positive corelation between OB-CCT and GAT IOP-b-IOP difference (Spearman's rho=0.378, P=0.001). The mean OB-CCT was 549.5±36.4 µm, and the Corvis-CCT was 556.1±41.5 µm (Spearman's rho=0.900, P<0.001). No statistically significant difference in the new indices provided by the updated Corvis ST was detected among the three groups. Compared with control eyes, POAG eyes had a significantly reduced applanation time 2 after adjusting for OB-CCT and GAT IOP (P=0.048). Corvis b-IOP and CCT correlate well with GAT IOP and OB-CCT. b-IOP is not affected by CCT, which might be an advantage, especially in thick or thin corneas. Corvis ST yields shorter applanation time 2 measurements in patients with POAG, which might reflect altered corneal viscoelasticity.

Ocular effects of mobile phone radiation

: To find out the adverse effects of prolonged mobile phone radiation on the users’ eyes. : A convenience sample of 200 adults visiting our out-patient’s services with 20/20 vision was randomly recruited for this study. The ipsilateral eye on the preferred side during talking was considered as the preferred side and the other as non-preferred side. All participants underwent Schirmer’s test (S1T), Tear film break-up time (TBUT), central corneal thickness (CCT) and central macular thickness (CMT) measurements for comparison on both the sides. The approximate cumulative duration of the talk time (hours/day) while keeping the phone over the ear was recorded.: The mean age of participants was 25.1+5.4 years and 124 (62%) preferred to use the right ear for telephonic conversations. The TBUT (19 + 2.7 vs. 20 + 3 seconds), Schirmer’s (21.5 + 2.8 vs. 22.6 + 2.5 mm), p &amp;#60;0.001 for both and CCT (527 + 20 vs. 530 + 19µ) (p= 0.005) were significantly lower in the preferred side. Multivariable linear regression showed that speaking on the phone for longer periods lead to slightly lower ipsilateral TBUT (0.31 seconds lower TBUT with every 1-hour increment in talk time, 95%CI= -0.67 to 0.03 seconds, p=0.07)but not Schirmer’s values.: Mobile phone use affects the tear fluid dynamics (TBUT and S1T) and the corneal thickness of the eye. Thus, any of the radiations or thermal effect or both from the mobile phones can affect the eye and its structures. Further studies are needed to address these consequences.

Agreement of Anterior Segment Parameter Measurements With CASIA 2 and IOLMaster 700.

PurposeTo compare the difference and agreement in central corneal thickness (CCT), keratometry (K), anterior chamber depth (ACD), aqueous depth (AQD), and lens thickness (LT) measured with CASIA 2 and IOLMaster 700 in patients with cataract.MethodsA total of 81 patients with cataract (81 eyes) scheduled for phacoemulsification were prospectively collected from March to May, 2020 in the cataract department of Zhongshan Ophthalmic Center, Sun Yat-sen University, including 43 males and 38 females with age of 61.5 ± 10.6 years. CCT, anterior Kf, anterior Ks, real Kf, real Ks, ACD, AQD, and LT were measured with CASIA 2 and IOLMaster 700. Paired t-test, intraclass correlation coefficients (ICCs), 95% limit of agreement (95% LoA), and Bland-Altman plots were performed and used to analyze the difference and agreement between the two devices.ResultsThere was no statistically significant difference in anterior K measurement with the CASIA 2 (44.3 ± 1.66 mm) and IOLMaster 700 (44.31 ± 1.67 mm, P = 0.483). Differences among the CCT, anterior Kf, real Kf, real Ks, ACD, AQD, and LT measured by the two instruments were statistically significant (P < 0.001). The ICCs of CCT, anterior Kf, anterior Ks, real Kf, real Ks, ACD, AQD, and LT measurements between the two devices were 0.892, 0.991, 0.991, 0.827, 0.817, 0.937, 0.926, and 0.997, respectively. The 95% LoA between CASIA 2 and IOLMaster 700 was −30.06 to 0.43 μm for CCT, −0.3 to 0.48 D for anterior Kf, −0.46 to −0.43 D for anterior Ks, −1.49 to −0.49 D for real Kf, −1.62 to −0.49 D for Real Ks, −0.03 to 0.24 mm for ACD, 0.04 to 0.25 mm for AQD, and −0.06 to 0.09 mm for LT.ConclusionAnterior Kf, anterior Ks, ACD, AQD, and LT have excellent agreement between the two devices. CCT, real Kf, and real Ks have moderate agreement between the two devices. It is recommended to use anterior Kf, anterior Ks, ACD, AQD, and LT interchangeably between CASIA 2 and IOLMaster 700.

Comparing Central Corneal Thickness Using Ultrasound and Anterior Segment Optical Coherence Tomography Pachymetry in Adults Attending A Private Eye Clinic in Abuja.

Central Corneal Thickness (CCT) measurement is useful in the management of glaucoma, ocular hypertension, corneal lesions and kerato-refractive surgeries. The study aims to compare the CCT measurements between Ultrasound Sonography (USS) and Optical Coherence Tomography (OCT), to analyze correlation and agreement between these instruments as well as repeatability of each instrument. A cross sectional comparative study carried in 100 eyes of 50 patients attending Rachel Eye Center in Abuja from January to March 2021. The CCT were taken using the USS and OCT. CCT was measured using the Pachscan ultrasound and the Optovue machine utilised for the OCT technique. Data was analysed using SPSS version 20 using Paired Sample t Test, Pearson's correlation, Interclass Correlation and Bland Altman Methods. Patients were aged between 18 and 79 (mean age of 39.1), 72 males and 28 females. The mean CCT was 537.36 ±33.26 and 510.94 ±33.13 for USS and OCT respectively with a mean difference of (26.42±9.53 p<0.001). There was a very strong correlation of the 2 sets of measurement r = 0.997 p<0.001. There was a high average mean intraclass correlation coefficient of 0.843 between the two instruments and this was excellent (0.961) within the 95 percentile upper limit but poor in the (0.096) lower limit. There was a high correlation and no statistical significant difference in the comparing repeated mean USS and OCT measurements. There was an excellent average mean Intraclass Correlation Coefficient of 0.999/0.997 for the repeated OCT and USS values and this was found to be excellent(0.999/0.998) within the 95 percentile upper limit and (0.997/0.994)lower limit respectively. We find that measurements of CCT using the Pachscan ultrasound and the Optovue OCT correlate well, but the mean Pachscan measures were significantly higher than Optovue measures.

Association Between Central Corneal Thickness and Growth Parameters Following Preterm

Objective: To investigate central corneal thickness in prematurely born children and to evaluate the association between central corneal thickness and growth pattern during 3 months following preterm birth. Methods: In this prospective study, central corneal thickness, head circumference, body length and body weight measurements were performed in 32 infants at monthly intervals during the first 3 months following preterm birth. Central corneal thickness measurements were performed by using an ultrasonic pachymetry. Initial central corneal thickness measurements were performed 24 – 48 hours after delivery. The head circumference, body length and body weight measurements were performed within 24 hours following birth by a neonatologist. All measurements were carried out at 1st month, 2nd month and 3rd month in the same manner. Results: There were 18 female (56.2%) and 14 male (43.8%) infants. The mean gestational age and body weight at birth were 27.8 weeks and 1042±309.9 g, respectively. The mean head circumference and body length at birth were 26.2 cm and 36.3 cm, respectively. Mean central corneal thickness at birth was 666.03±92.6 µm. Central corneal thickness significantly decreased during the study period (p<0.001). Head circumference, body length and body weight showed significant increases following birth (p<0.001 for each). There was a significant negative correlation of central corneal thickness change with the body length change between 1st month and 2nd month (p<0.05). Conclusion:In this study, decrease of corneal thickness in prematurely born infants was found to be inversely correlated to body length alterations in early months of life. Key Words: Body length, Body weight, Central corneal thickness, Head circumference measurement, Premature

The Effect of Artificial Tear Treatment on Central Corneal Thickness in Dry Eye

Purpose: To evaluate the effect of artificial tear treatment on central corneal thickness in dry eye patients using corneal topography. Materials and Methods: In this before and after study, central corneal thickness measurements using corneal topography (SIRIUS CSO ITALIA) were performed on 192 eyes of 96 patients with dry eye at the ophthalmology department of Tishreen University Hospital/Lattakia from August 2020 to August 2021. Patients underwent ocular examinations, including Schirmer test, slit lamp examination for tear break-up time (BUT), and central corneal thickness (CCT) measurements using corneal topography before and after artificial tear treatment (carboxymethylcellulose and sodium hyaluronate 0,5% eye drop formulations) 3-4 times a day for one month, patients were examined again at a second visit and the results were compared. Results: The mean CCT was (545.79±10.5) before treatment and (571.30±11.3) after treatment (p=0.0001, p=0.0001). CCT statistically significantly increases of 4,7% from baseline (p=0.000) 1. The mean tear BUT and Schirmer-1 tests revealed significant improvement after treatment. Conclusion: Artificial tear treatment in dry eye patients significantly increases the central corneal thickness. This increase could be used as a criterion in the diagnosis and follow up of dry eyes, and this increase in thickness should be considered in intra ocular pressure measurements as well as in refractive surgical procedures.

Central Corneal Thickness Measurements with Different Imaging Devices: Ultrasound Pachymetry, Noncontact Specular Microscopy, and Tono-Pachymetry.

Objectives:Investigation of the compatibility between central corneal thickness (CCT) measurements in healthy eyes by comparing standard ultrasound pachymetry (USP) with noncontact tono-pachymetry (NCT) and specular microscopy (SM) devices was aimed.Methods:Forty-five eyes of 45 healthy volunteers aged between 18 and 60 years were included in this study. CCT of all cases was evaluated with USP, NCT, and SM devices. The same examiner performed all examinations. Bland–Altman plots and intraclass correlation coefficients were used to evaluate the agreement between instruments.Results:The mean age of the patients was 31±10.2 years. Fifteen (33.3%) cases were male and 30 (66.7%) were female. The mean CCT measured using NCT (559.3±39 µm) was significantly higher than those measured using SM (534.8±41 µm) and USP (542.6±43 µm, p<0.001). Bland–Altman analysis showed that the difference between the first, second, and third measurements was evenly dispersed around the mean, with no clear trend toward over- or underestimation by either NCT, USP, or SM. The 95% limits of agreements were 0.30–48.72 µm for NCT, –12.63–46.04 µm for the USP, and –24.41–8.80 µm for the SM. Correlation analysis between the three devices showed a very strong positive correlation (p<0.001).Conclusion:Significant differences were observed between CCT measurements in healthy individuals used in ophthalmology practice and performed with different devices. This situation should draw attention to the fact that in diseases such as glaucoma and endothelial insufficiency, corneal thickness monitoring should be done with the same device and the devices should not be used interchangeably.

Differences and Limits of Agreement among Pentacam, Corvis-ST, and IOL-Master 700 Optical Biometric Devices regarding Central Corneal Thickness Measurements.

Purpose:To investigate the differences and limits of agreement in measuring corneal thickness using Pentacam, Corvis, and intraocular lens (IOL)-Master 700 devices.Methods:This study was conducted on 37 right eyes of 21 males and 16 females (n = 37) with a mean age of 52.11 ± 6.30 years. The central corneal thickness was measured using three optical biometric devices, including Pentacam, Corvis, and IOL-Master 700. The inclusion criteria were normal eyes without any ophthalmological abnormalities, history of ocular pathology, or ocular surgery. The data obtained from these three devices were compared two by two. The correlation and agreement limits among them were analyzed using statistical techniques.Results:The mean standard deviation differences between Pentacam and Corvis, Pentacam and IOL-Master 700, as well as Corvis and IOL-Master 700 regarding the corneal thickness measurement, were 22.13 ± 8.05, 7.91 ± 8.02, and 14.21 ± 9.85 μm, respectively, which were statistically significant (P < 0.0001). Based on the investigation of the limits of agreement according to the Bland Altman method, the corresponding values between Pentacam and Corvis, Pentacam and IOL-Master 700, and Corvis and IOL-Master 700 were -16.2 to +15.4, -15.8 to +16.3, and -20.1 to +20.0 μm, respectively. Furthermore, the correlation coefficients of the measurements obtained by Pentacam and Corvis, Pentacam and IOL-Master 700, as well as Corvis and IOL-Master 700 were determined 0.957, 0.964, and 0.948, respectively (P < 0.0001).Conclusion:The results from this study indicate that the interchangeable use of these three devices is not appropriate due to statistically significant differences and broad limits of agreement among the three devices, especially between Corvis and IOL-Master 700.

Corneal Effect of Air Bubble After Phacoemulsification.

The aim of the study was to investigate the effect of air bubble on the cornea at the end of the cataract surgery with phacoemulsification. This prospective and case-control study included 71 patients with air bubble injected into the anterior chamber at the end of the operation and 63 age-sex-matched control patients without air bubble. Endothelial cell density (ECD), coefficient of variation (CV), hexagonality rate (HEX), and central corneal thickness (CCT) measurements were taken using non-contact specular microscopy preoperatively and at 1-day, 1-week, and 1-month postoperatively. No significant difference was determined between the groups preoperatively in respect of mean visual acuity, anterior chamber depth, ECD, CV, HEX, and CCT values (p>0.05). The intraoperative average ultrasound power, effective phaco time, and ultrasound time values were similar (p>0.05). The CCT value was lower in the study group than in the control group on post-operative day 1 (p=0.012), but similar at 1 week and 1 month (p=0.102, p=0.330, respectively). No significant difference was determined between the groups in mean visual acuity, anterior chamber reaction, ECD, CV, and HEX values at 1-day, 1-week, and 1-month postoperatively (p>0.05). Air bubble may be used as an alternative method to reduce corneal edema on the 1st post-operative day. According to the results, although air bubble has no detrimental effect, there is also seen to be no protective effect on the corneal endothelium.

The short-term effects of intravitreal bevacizumab injection on intraocular pressure, cornea, iridocorneal angle, and anterior chamber.

Transient increase in intraocular pressure (IOP), changes in anterior chamber parameters, and changes in aqueous humor dynamics may occur after intravitreal injections because of intravitreal volume changes. In this observational study, we investigated the early effects of intravitreal bevacizumab (IVB) injection on IOP, central corneal thickness (CCT), corneal volume (CV), anterior chamber depth (ACD), and iridocorneal angle (ICA). The patients who had one single-dose IVB (2.5 mg/0.1 mL) injection were included in the study. The patients underwent IOP, CCT, CV, ACD, and ICA measurements before and 1 h and 1 day after the injection. Pre-injection and post-injection values were compared. Forty-two eyes of 42 patients were included in the study, and the mean age of patients was 60.1 ± 7.4 years. The mean IOP measurements before and after injection at 1 h and day 1 were 15 ± 2.4, 17.4 ± 2.4, and 14.7 ± 2.3, respectively. The mean IOP, CCT, and CV values 1 h after injection were significantly higher than pre-injection values (p < 0.05, p < 0.05, and p = 0.02, respectively). Conversely, mean ACD and ICA values 1 h after injection were significantly lower than pre-injection values (p = 0.01 for both). There were no statistically significant differences on the first day after injection for all parameters. IVB (2.5 mg/0.1 mL) injection causes transient increases in IOP and transient decreases in ACD and ICA at the first hour after injection. Related to elevation in IOP, CCT and CV may increase transiently. These changes return to baseline values on the first day after injection.

Результаты применения функциональных методов исследования у детей с сахарным диабетом 1 типа в зависимости от уровня гликированного гемоглобина

Aim: to assess correlations between ocular ultrasound (US) biometry and optical coherence tomography (OCT) and hemoglobin A1c (HbA1c) in children with type 1 diabetes (T1D). Patients and Methods: 79 children were enrolled. The control group included 52 age-matched healthy children. Axial length (AL, mm) and lens thickness (LT, mm) were measured by US. Central corneal thickness (CCT) and central macular thickness (CMT) were measured by OCT (Cirrus 2000, Carl Zeiss Meditec, Germany). Correlation analysis to assess the relationship between HbA1c, US, and OCT was performed. Results: 55.7% of the participants were boys (n=44) and 44.3% were girls (n=35). Children were assigned into six groups depending on HbA1c levels. Group 1 (HbA1c &lt;6.0%) included 8 children, group 2 (HbA1c 6.1–7.0%) 29 children, group 3 (HbA1c 7.1–8.0%) 21 children, group 4 (HbA1c 8.1–9.0%) 8 children, group 5 (HbA1c 9.1–10%) 5 children, and group 6 (HbA1c &gt;10%) 8 children. The mean AL was 22.7±1.1 mm. The greatest AL was reported in groups 2 and 4, while the least AL was reported in groups 3 and 6. The greatest LT was reported in groups 4 and 6. In group 1, LT was similar to those in the control group. In all groups but group 2, CCT was greater than in controls. CMT demonstrated a negative correlation with HbA1c levels in the study groups. CMT was the greatest in children with T1D of 5 years’ durati Conclusion: in children with T1D, US and OCT findings correlate with HbA1c levels and T1D duration. Ocular biometry, CCT, and CMT measurements are useful tests illustrating the level of compensation of systemic disease. Dynamic assessment of these parameters will help develop indicators of diabetic retinopathy in children with T1D. Keywords: diabetes, ultrasound, optical coherence tomography, glycated hemoglobin. For citation: Abdulina V.R., Stepanova I.S. Functional tests in children with type 1 diabetes and their correlation with hemoglobin A1c levels. Russian Journal of Clinical Ophthalmology. 2022;22(2):99–102 (in Russ.). DOI: 10.32364/2311-7729-2022-22-2-99-102.

Correlation of Corneal Thickness Measurements Between Tono-pachymeter and Scheimpflug- Placido Topography

Central corneal thickness (CCT) measurements are important for diagnosis, treatment, and surgery planning in ophthalmology. The purpose of this study was to see whether CCT measurements taken with Tono-pachymeter and Scheimpflug- Placido Topography had any significant differences. Tono-pachymeter and topography CCT measurements were taken (n=400). Inter-measurement agreement between them was determined using Bland-Altman Plot analysis. Age groups were also formed as group 1 (aged 18-50 years, 94 males, 106 females) and group 2 (age &gt;51 years, 100 males, 100 females). Mean CCTs measured by Tonopachymeter and topography were 563.77 +±26.43 and 560.88 + 26.341 microns. Bland-Altman Plot analysis showed in total, 13 were above the upper limit and 5 were under the minimum limit of agreement with regression analysis showing no significant relationships (p=0.213). Group 1 had 7 above and 2 below from the limits of agreement. Group two had 9 above and 2 below from the limits of agreement. Both groups showed insignificant differences between devices (p=0.07 and p=0.86). Tono-pachymeter and Scheimpflug-Placido Topography give reliable CCT results within each other. However, since the limit of agreement ranges can still affect one-to-one patient evaluations, we recommend clinics that use these devices to not interchange measurements in practice.

Épaisseur cornéenne centrale chez les enfants mélanodermes examinés sous anesthésie générale au Centre hospitalier universitaire Yalgado Ouédraogo

Central corneal thickness measurement permits an evaluation of physiological and pathological corneal changes. It allows for an intra-ocular pressure correction factor. Our purpose was to determine the mean central corneal thickness in children aged 0 to 72 months and to examine factors that might affect it. This was a cross-sectional hospital study which took place from February to December 2019 in the ophthalmology service of YO University Medical Center. It included healthy eyes of children 0-72 months of age examined under general anesthesia. Ultrasonic pachymetry was used to measure the central corneal thickness. The studied variables were age, sex, CCT, corneal diameter, intraocular pressure, and cup/disc ratio. One hundred and twenty-seven healthy eyes of 78 children 0-72 months of age were included. The mean age was 22 months. The overall mean CCT was 554.01±34.21μm. It was 556.58μm for children from 0 to 36 months of age and 536.12μm for subjects over 36 months. The mean CCT was 555.96±32.96μm in boys and 551.80±36.16μm in girls. In patients who underwent bilateral CCT measurement, the mean CCT was 554.74±35.67μm in the right eye and 549.76±24.08μm in the left eye. Lower IOP's were found in patients with thicker corneas (p=0.00). The CCT values for black children over 36 months of age was similar to the CCT in black adults.

Agreement of anterior segment measurements between four diagnostic imaging devices in myopic patients

ABSTRACT Purpose To compare the inter-device agreement of anterior chamber depth (ACD), central corneal thickness (CCT), flat keratometry (K1), steep keratometry (K2), corneal astigmatism (ΔK), and white-to-white (WTW) measurements. Methods This is a retrospective study with 73 myopic patients (142 eyes). We extracted and compared anterior segment measurements (ACD, CCT, K1, K2, ΔK, and WTW) of four devices (OPD-Scan III, Pentacam HR, Lenstar LS 900, and Galilei G4), and performed pairwise agreement comparisons between them. Results Agreement analyses revealed that the most agreement occurred: in Pentacam HR and Galilei G4 for ACD measurements, in Pentacam HR and Lenstar LS 900 for CCT measurements, in OPD-Scan III and Galilei G4 for WTW measurements, in OPD-Scan III and Pentacam HR for K1 and K2 measurements, and OPD-Scan III and Galilei G4 for ΔK measurements. Conclusion OPD-Scan III is interchangeable with both Galilei G4 and Lenstar LS 900 for WTW measurements. OPD-Scan III and the Pentacam-HR are interchangeable in K1, K2, and ΔK measurements. OPD-Scan III and Lenstar LS 900, and OPD-Scan III and Galilei G4 are interchangeable in K1 and ΔK measurements, respectively.

Determining the mean difference in central corneal thickness measured by applanation ultrasound and oculus Wavelight Occulyzer II

Abstract&#x0D; Objective: The objective is to determine the mean difference of central corneal thickness measurements by using ultrasound pachymeter and oculus Wavelight Occulyzer II.&#x0D; Patients &amp; Methods: This prospective cross-sectional comparative study was conducted at Department of Ophthalmology, Liaquat National Hospital, Karachi for 6 months duration, after the approval from ethical committee. Patients were included in our study on the basis of inclusion &amp; exclusion criteria. Central corneal thickness measurements was taken by using ultrasound pachymeter &amp; oculus Wavelight Occulyzer II. All the data was collected by single researcher. The results were plotted, compared &amp; analyzed.&#x0D; Results: 130 patients attending ophthalmology department and fulfilling the inclusion criteria were assessed. One eye of each patient was measured (65 were right eye and 65 were left eye). 73(56.2%) were male and 57(43.8%) were females. Mean age of these patients was 33.9 ±8.9 years. The mean ± SD thinnest oculus Wavelight Occulyzer II measurement was 538.61±23.46 ?m and ranged between 476.0 and 619.0 ?m whereas the mean thinnest ultrasound pachymeter measurement was 535.1±21.816?m and ranged between 482 and 601 ?m. There was highly significant correlation of central corneal thickness between both the instruments. (r=0.96, p&lt;0.001) &#x0D; Conclusion: According to the results of our study there is a highly correlation of central corneal thickness was found between the readings obtained from both UP and oculus Wavelight Occulyzer II. So we concluded that oculus Wavelight Occulyzer II can be used as an alternative technique to ultrasound pachymetry while assessing CCT in clinical settings to decrease the risk of procedure associated problems with UP like epithelial trauma and infection, to decrease the frequent use of topical anesthetic agents, for early detection and management of glaucoma &amp; in anxious patients also.&#x0D; Keywords: Central corneal thickness, ultrasound pachymeter, oculus Wavelight Occulyzer II&#x0D;

Ocular blood flow and choroidal thickness in ocular hypertension.

Ocular hypertension (OHT) is a clinical entity characterized by elevated intraocular pressure (IOP) without optic nerve damage. In the presence of other risk factors, OHT may progress to glaucoma. This study aimed to evaluate ocular blood flow (OBF) and choroidal thickness (CT), which may be markers and/or risk factors that could assess the progression of OHT to glaucoma. Age and gender matched 60 eyes of 32 patients with OHT and 61 eyes of 31 control patients were included for this study. All participants underwent a detailed ophthalmological examination including best-corrected visual acuity, IOP measurement with Goldmann applanation tonometry, gonioscopy, optic nerve evaluation with 78 D lens, and visual field test with Humphrey visual field analyzer. Retinal nerve fiber layer, ganglion cell complex, and central corneal thickness measurements were performed by optical coherence tomography (OCT). CT was measured with OCT in the fovea, 1.5mm, 2mm, 2.5mm nasal and temporal to the fovea and from nasal and temporal to the optic disk. OBF data including peak systolic velocity (PSV), end-diastolic velocity (EDV), resistivity index (RI) and pulsatility index (PI) were measured with color Doppler imaging (CDI) from the ophthalmic artery (OA), central retinal artery (CRA), medial and lateral branches of short posterior ciliary arteries (MPCA, LPCA). Systolic (SBP) and diastolic arterial blood pressure were also noted. CT measurement at each point in the OHT group compared to the control group were found to be significantly thinner (p = 0.001). There was a decrement in CT from the fovea to the nasal and temporal retina in both groups. In the OHT group, there was a significant decrease in PSV and EDV of OA, CRA, MPCA, and LPCA, and a significant increase in PI and RI of measured arteries. (EDV p = 0.036, PI p = 0.006, RI p = 0.006 for OA and p = 0.001 for other arteries and all OBF measurements). There was a negative correlation between CT and age, IOP and axial length (AL) in OHT group (r = - 0.529, p = 0.001; r = - 0.258, p = 0.047; r = - 0.345, p = 0.007, respectively, for fovea). But there was no statistically significant correlation between CT and other measurements in the control group, except age (r = - 0.860 p = 0.001 for fovea). We found that OBF decrement and choroidal thinning in OHT group compared with controls. Interpretation both of CT measurements with OCT and OBF parameters with CDI and new imaging technologies may help to prevent and reduce the possible optic nerve damage.

CHANGES IN CENTRAL CORNEAL THICKNESS IN HEALTHY PREGNANT WOMEN-A CLINICAL STUDY

Aim of the Study: To determine the changes in central corneal thickness during pregnancy in healthy pregnant women. Methods: 50 pregnant women aged between 25 years to 35 years, not suffering from refractive errors and with no prior history of Kerato-refractive procedures and not suffering from any medical or surgical complications of pregnancy, attending to the OPD of OBG Department of King George Hospital-Andhra Medical College, Visakhapatnam were included in our study. Central Corneal Thickness (CCT) was measured in all these 50 pregnant women with a hand held portable automated corneal Pachymeter. CCT measurements were made in the first, second, third trimesters and also after a period of 3 months from date of delivery. Results: The mean CCT was found to be significantly higher in the second and third trimesters, compared with the first trimester and at a period of 3 months postpartum (p &lt; 0.001). Conclusion: The CCT value was significantly higher in the second and third trimesters of pregnancy.CCT is an important factor to be considered while measuring Intra Ocular Pressure (IOP). The IOP measurements in pregnant women should always be corrected for CCT thereby preventing false high or low recordings of IOP.The target IOP should be carefully decided after taking into consideration the changes in CCT values in pregnant women with glaucoma.The changes in CCT during pregnancy should be kept in mind while performing any refraction or corneal topography studies during pregnancy.

A comparison of central corneal thickness measured using noncontact methods and ultrasonic pachymetry.

The aim of this study is to compare central corneal thickness (CCT) measurements in healthy eyes using ultrasonic pachymetry (UP) with values obtained using anterior segment spectral domain optical coherence tomography (SD-OCT), the Scheimpflug camera system, and noncontact specular microscopy. One hundred and twenty-five eyes of 117 healthy individuals (56 women, 61 men) were included. All patients underwent consecutive CCT measurement with UP, the Scheimpflug camera, anterior segment SD-OCT, and specular microscopy. The four devices could be read. Measurements from the four devices were classified in pairs and compared using the paired t-test. Relations between the devices were analyzed using the Pearson test. An alpha error level of P < 0.05 was regarded as statistically significant. The mean age of the healthy individuals included in the study was 34.75 ± 14.55 years (20-76). Mean CCT values were 541.21 ± 29.24 μm with UP, 539.26 ± 29.27 μm with the Scheimpflug camera system, 532.21 ± 29.53 μm with SD-OCT, and 534.45 ± 29.20 μm with specular microscopy. The differences in measurements at the paired t-test were statistically significant (P < 0.001 for all). However, measurements using the four devices exhibited significant mutual correlation (P < 0.001 for all). CCT can be measured using different devices. Noncontact methods have now begun replacing UP, regarded as the gold standard. Although CCT values obtained from different devices were correlated, the difference between these measurements was statistically significant. Therefore, the same device should be used for measurement in the diagnosis and follow-up of diseases such as corneal ectasia and glaucoma where corneal thickness is important.

COMPARISON OF INTRAOCULAR LENS IMPLANTATION WITH AND WITHOUT VISCOELASTIC SUBSTANCES IN PHACOEMULSIFICATION

Background: Life expectancy of the population may increase and cataract development may affect all the people with aging. Intraocular lens implantation surgery, a worldwide performed procedure, evolves and progresses. However, different techniques exist, which could be selected for different cases. Any ideal technique should be safe, simple, fast, and easy to learn with good clinical outcome. Objective: The aim of this work was to compare the efficacy and safety of intraocular lens implantation with and without ophthalmic viscoelastic device after phacoemulsification as well as surgery duration and post-operative intraocular pressure and central corneal thickness. Patients and methods: This was a prospective, randomized controlled trial conducted on 40 eyes with cataract; to compare the efficacy and safety of intraocular lens implantation with and without ophthalmic viscoelastic device after phacoemulsification of the lens as regard to surgery duration, post-operative intraocular pressure and central corneal thickness. Patients were evaluated 1 day, 1 week, and 1 month postoperatively. Patients were divided into two groups after the completion of lens cortex removal: Group A (n=20, hydro-implantation): One-piece acrylic intraocular lens implantation was performed with normal saline solution (0.9 solution) irrigation. Group B (n=20, visco-implantation): using Hydroxy-propyl-methyl-cellulose 2% implantation. Results: Highly significant increase in phaco operative time in visco-implantation group; compared to hydro-implantation group (p 0.05 respectively). Non-significant difference as regards post-operative Central corneal thickness (CCT) (p > 0.05). Non-significant increase in post-operative CCT measurements in visco-implantation group (p > 0.05). Non-significant difference in post-operative IOP measurements in visco-implantation group (p > 0.05). Non-significant decrease in post-operative IOP and CCT measurements in hydro-implantation group (p > 0.05). Non-significant decrease in post-operative IOP in hydro-implantation group; compared to visco-implantation group; during the serial 1st and 2nd measurements. Non-significant increase in post-operative CCT in Visco-implantation group; compared to hydro-implantation group; during the serial 1st and 2nd measurements. Conclusion: The hydro-implantation had similar clinical outcome to visco-implantation with advantage of reduced surgical time and cost, and no ophthalmic viscosurgical devices (OVD) induced intraocular pressure elevation postoperatively.