Increase In Central Corneal Thickness Research Articles

Effectiveness of intraoperative intraocular lens use on improving surgical safety for dense cataract phacoemulsification: a randomized controlled trial

We designed this study to assess if surgical safety can be improved by intraoperative use of intraocular lens (IOL) for cataract phacoemulsification. We performed phacoemulsification cataract removal on 401 patients. We randomly assigned these patients into three groups: the standard setting (Group I, n = 134), with reduced vacuum and flow rate (Group II, n = 137), and with IOL insertion before the last quadrant was emulsified with standard setting (Group III, n = 130). The primary outcomes included the risk of posterior capsular rupture (PCR), ultrasound time, energy, and complications. The secondary outcomes included central corneal thickness (CCT), CCT changes, endothelial cells (ETC) counting, ETC loss, and the best corrected distance visual acuity (BCVA) measured on day 1, day 7 and day 30. If PCR occurred, we emulsified the residual lens materials after insertion of IOL and clean of the prolapsed vitreous. We found that the risk of PCR in Group III (0/130) was lower than Group I (9/134, corrected relative risk (RR) = 18.44, 95% CI: 1.08–313.56) and Group II (3/137, corrected RR = 6.64, 95% CI: 0.35–27.41). Group III showed better BCVA on day 1 and 7, less ECC loss on day 7 and 30, and less CCT increase on day 1 and 7. No cases converted to extracapsular cataract extraction. No residual lens materials misdirected into vitreous cavity. Intraoperative use of IOL can improve surgical safety for dense cataract phacoemulsification.

Evaluation of anterior segment parameters in pars plana vitrectomy and silicone oil injection

Purpose The aim of this study was to compare the changes in anterior segment parameters induced by pars plana vitrectomy (PPV) and silicone oil injection in phakic and pseudophakic eyes.Patients and methods This is a prospective comparative study that included 40 eyes with rhegmatogenous retinal detachment that underwent vitrectomy and silicone oil injection. They were divided equally into two groups. Group 1 included phakic eyes and group 2 included pseudophakic eyes. Anterior segment parameters were documented by using a CSO Camera (Costruzione Strumenti Oftalmici) before and 1 month after surgery. The changes in the following parameters were compared between the two groups: anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), central corneal thickness (CCT), corneal volume (CV), horizontal anterior chamber diameter, and surgically induced astigmatism.Results At 1 month postoperatively, in group 1, there was a significant decrease in the mean of ACA and ACV as compared with the preoperative values (P=0.024 and 0.011, respectively). In group 2, there was a significant decrease in the 1-month postoperative mean of ACD, ACA, and ACV as compared with the preoperative values (P=0.021, <0.0001 and 0.015, respectively) and a significant increase in the mean of CCT and CV values (P<0.0001 and 0.002, respectively). In group 2, there was more reduction in ACD, less reduction in ACA, and higher increase in CCT and CV as compared with group 1 (P=0.021, 0.001, <0.0001, and 0.023, respectively).Conclusion The presence of the crystalline lens acts as a barrier which decreases the changes in the anterior segment parameters and improves the functional outcome following PPV and silicone oil injection as compared with pseudophakia. Therefore, it may be useful to stabilize the anterior segment in patients with PPV and silicone oil injection.

Biomechanical properties of the cornea as predictors of the effectiveness of selective laser trabeculoplasty

To study the changes in central corneal thickness (CCT) and corneal hysteresis (CH) after selective laser trabeculoplasty (SLT) in primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) after laser peripheral iridotomy (LPI) and to determine their effect on the prognosis of the surgery. The prospective study involved 68 eyes with initial PACG after LPI and 74 eyes with initial POAG observed for 6 months. Corneal-compensated IOP (IOPcc), corneal resistance factor (CRF), CH and CCT were studied as the predictors of SLT, which was considered successful when IOPcc decreased by 20% or more from the baseline without additional hypotensive therapy and/or repeated SLT. In both forms of glaucoma, CCT increased within the first hour after SLT: 567±24.08 µm (p=0.001) in POAG, and 572±21.41 µm (p=0.000) - persisting for over a month - in PACG. CCT correlated with laser energy at all stages of the examination both in POAG and PACG patients. The following predictors of SLT failure were determined: CH (p=0.000 in PACG and p=0.001 in POAG), as well as initial IOP (p=0.010 in PACG and p=0.016 in POAG) and CRF (p=0.003 in PACG and p=0.005 in POAG) and CCT (p=0.023 in PACG and p=0.026 in POAG). The value of anterior chamber angle (ACA) was a predictor only for PACG (p=0.011). SLT leads to an increase in CCT, which lasts longer in PACG after LPI than in POAG and correlates with the level of laser energy. Lower CH and initially higher IOP are the common predictors of SLT failure in the long term for both forms of glaucoma. Smaller ACA have a negative prognostic sign in POAG.

A Comparative Study of Central Corneal Thickness and Endothelial Cell Density after Phacoemulsification by ‘Phaco-chop’ and ‘Divide and Conquer’ Techniques

Introduction: Phacoemulsification was introduced by Kelman in 1967. It is one of the most important innovations in ophthalmology. This has now been accepted as gold standard surgical procedure for management of cataract. Divide and conquer technique, described by Gimbel, was the first nucleofractis cracking technique developed. Phoc-chop technique was presented by Kunihiro Nagahara in 1993 at the meeting of America Society of Cataract and Refractive Surgery. Aim: To compare the Central Corneal Thickness (CCT) and endothelial cell density after phacoemulsification by ‘phaco-chop’ and ‘divide and conquer’ techniques. Materials and Methods: The study included 100 patients divided into two groups, each including 50 patients; Group A, where Divide and Conquer was performed, and in Group B Phaco-chop was performed. The mean Absolute PhacoTime (APT), mean Endothelial Cell Count (ECC), mean Endothelial Cell Loss (ECL), corneal thickness and the visual acuity were reported in the two groups both preoperative and postoperative. Results: The mean APT in group A was 27.12±10.15 seconds, and in group B was 16.58±5.11 seconds (p=0.0001). The mean ECC at sixth week postoperative in group A was 2102. 14 cells/mm2 and in group B it was 2365.38 cells/mm2 (p=0.003). There was statistically significant ECL following sixth week postoperatively 16.22% in divide and conquer group and 8.51% in phaco-chop group (p-value=0.0001). A significant increase in the CCT was observed at the immediate postoperative week among the two studied groups; 3.16% in group A and 2.34% in group B, which was statistically significant. The postoperative CCT pachymetry values were returned to near preoperative values at one and a half months postoperative. Conclusion: The phaco-chop technique utilises less phaco time and energy without significant effect on the final surgical outcome. Significant and equal ECL occurs after the two studied techniques. APT and nuclear grade have a positive correlation with higher ECL. CCT increases significantly and equally postoperatively following the two techniques.

Repeatability of new Corvis ST parameters and influencing factors in myopia patients

Objective To evaluate the repeatability of corneal biomechanics parameters measured by Corneal Visualization Scheimpflug Technology (Corvis ST) and explore the factors that influence the repeatability. Methods A diagnostic test study was performed.A total of 190 eyes in 95 myopia patients (34 males and 61 females) were enrolled from September to October 2017 in Henan Eye Hospital.All the subjects underwent 5 repeated examinations with the Corvis ST.The intraclass correlation coefficient (ICC), Cronbach α coefficients and repeatability coefficient (RC) were computed to evaluate repeatability of Corvis ST parameters.The multiple linear regression analysis was used to study the factors that affect the magnitude of the test-retest variability (within subject SD) of new Corvis ST parameters.This study was approved by the Ethics Committee of Henan Eye Hospital (HNEECKY-2019[5]), and written informed consent was obtained from each subject. Results Among the 39 biomechanics parameters, The ICC and Cronbach α were greater than 0.75 for 26 parameters, within 0.60-0.75 for 4 parameters, and lower than 0.60 for deflection amplitude max time (DLAMT). The ICC and Cronbach α of DA ratio max[1 mm], DA ratio max [2 mm], max inverse radius, Ambrosio's relational thickness horizontal (ARTh), biomechanical intraocular pressure (bIOP), integrated radius, stiffness parameter applanation 1 (SPA1) and Corvis biomechanical index (CBI)were all above 0.920.The multivariate regression results indicated that the within subject SD of bIOP increased with the increase of IOP (β=0.210, P=0.010). The within subjects SD of DA Ratio Max [1 mm]decreased with the increase of central corneal thickness (CCT) (β=-0.218, P=0.008). The within subjects SD of DA Ratio Max [2 mm]decreased with the increase of CCT(β=-0.295, P<0.001). The within subject SD of CBI decreased with the increase of astigmatism, axial lengths and CCT (β=-0.190、-0.148、-0.428, all P<0.05). Conclusion The Corvis ST parameters showed favorable measurement repeatability in myopia patients, especially for the new parameters.Astigmatism, axial lengths and CCT significantly affected the repeatability of CBI. Key words: Cornea; Biomechanics; Myopia; Repeatability; Test-retest variability; Influence factors

Effect of Scleral Lens Wear on Central Corneal Thickness and Intraocular Pressure in Patients With Ocular Surface Disease.

To determine the effect of scleral lens wear on central corneal thickness (CCT) and intraocular pressure (IOP). Twenty-five subjects (46 eyes), fit with scleral lenses that ranged in diameter from 17.0 to 18.0 mm, were included in this retrospective study at the University of Southern California, Department of Ophthalmology. All subjects had ocular surface disease and were categorized into the following groups based on etiology of their dry eye: chronic graft versus host disease, Stevens-Johnson syndrome, Sjögren syndrome, or general dry eye syndrome. Measurements of CCT and IOP were obtained at the initial scleral lens consultation (pre-CCT and pre-IOP) and at follow-up visits (post-CCT and post-IOP) immediately after lens removal. The total average difference between pre-CCT and post-CCT was 7.19 μm (544.90±31.29 vs. 552.09±30.30 μm), which was a statistically significant increase of 1.01% (P≤0.05). On the other hand, the total average difference between pre-IOP and post-IOP was -0.89 mm Hg (14.47±3.63 vs. 13.58±3.61 mm Hg), which was not statistically significant (P≥0.05). There were no statistically significant correlations between change in CCT (ΔCCT) and visual acuity (P≥0.05), between ΔCCT or change in IOP (ΔIOP) in relation to lens diameter (P≥0.05), between etiology of dry eye affecting ΔCCT or ΔIOP (P≥0.05), between wearing time today and ΔCCT or ΔIOP (P≥0.05), and between average wearing time (AWT) and ΔCCT (P≥0.05). In addition, there was no statistically significant correlation between AWT and ΔIOP (R=0.0796) over a range of wear time hours. There was a statistically significant increase in CCT after scleral lens wear in subjects with ocular surface disease, which may be attributed to subclinical hypoxic conditions created by scleral lens wear. No significant relationship was found between scleral lens wear and IOP.

Predicting the Prognosis of Fuchs Endothelial Corneal Dystrophy by Using Scheimpflug Tomography

To determine if Scheimpflug tomography pachymetry map and posterior elevation map patterns, central corneal thickness (CCT), and corneal backscatter can predict the prognosis of Fuchs endothelial corneal dystrophy (FECD). Cross-sectional study with follow-up of outcomes. Ninety-six eyes (56 subjects) with a range of severity of FECD. Corneas were graded by cornea specialists according to the area and confluence of guttae and the presence of clinically definite edema. Masked and randomized Scheimpflug imaging pachymetry map and posterior elevation map patterns were assessed by 1 observer for loss of regular isopachs, displacement of the thinnest point of the cornea, and the presence of posterior surface depression. The prognosis of eyes over a 5-year (median) follow-up period was determined based on FECD progression (new onset of clinically definite edema or ≥5% increase in CCT) or intervention by endothelial keratoplasty. Cumulative probabilities of progression and intervention were estimated from survival analyses, with risk factors determined by using Cox proportional hazards models. Pachymetry map and posterior elevation map patterns, corneal backscatter, and CCT (ultrasonic pachymetry). In univariate analyses, loss of regular isopachs (hazard ratio [HR], 18.00) displacement of the thinnest point (HR, 11.53), focal posterior surface depression (HR, 10.21), and anterior corneal backscatter (HR, 1.22, per 1-grayscale unit increment), were risk factors for progression or intervention (P < 0.001), whereas CCT (HR, 1.30, per 25-μm increment) was not (P = 0.15). In multivariate analyses, loss of regular isopachs (HR, 11.57; P < 0.001) and displacement of the thinnest point (HR, 5.61; P= 0.02) were independent and clinically important risk factors for progression and intervention. The 5-year cumulative risk of disease progression and intervention was 7%, 48%, and 89% when none, 1 or 2, and all 3 pachymetry map and posterior elevation map parameters were present, respectively (P <0.001). The 4-year cumulative risk of disease progression and intervention after uncomplicated cataract surgery was 0%, 50%, and 75% when none, 1 or 2, and all 3 pachymetry map and posterior elevation map parameters were present, respectively (P < 0.001). Three Scheimpflug tomography pachymetry map and posterior elevation map patterns can predict FECD prognosis independent of CCT. The risk of FECD progression and intervention, including after uncomplicated cataract surgery, increases according to the number of parameters present.

Effect of glaucoma drainage implant surgery on corneal topography: a prospective study.

To study the effect of glaucoma drainage implant (GDI) surgery on corneal topography during the first postoperative year. Twenty-one adult glaucoma patients were implanted with a Molteno3 or a Baerveldt 250 GDI. Corneal topography measurements were taken preoperatively and at 6 and 12months after surgery. Untreated opposite eyes served as controls. In the surgical group, the mean±SD simulated average keratometry values were 44.36±1.69 D, 44.08±1.29 D (p=0.266) and 44.15±1.32 D (p=0.554) before and 6 and 12months after surgery, respectively. The corresponding simulated keratometry astigmatism values were 1.11±1.11 D, 1.20±1.01 D (p=0.687) and 1.16±0.71 D (p=0.177). Posterior astigmatism and posterior average keratometry remained unchanged after GDI surgery as well. The mean±SD central corneal thickness (CCT) was 530±46μm, 535±56μm (p=0.049) and 536±45μm (p=0.080) at 0, 6 and 12months, respectively. A trend towards increased corneal thickness (CT) in response to GDI surgery was also seen in both the average peripheral and the tube-quadrant peripheral CT values. At 12months postoperatively, the mean endothelial cell density (ECD) had decreased by 8% centrally and by 9% peripherally. Corneal topography parameters, CT and ECD did not significantly change in the control group during follow-up. Glaucoma drainage implant (GDI) surgery did not significantly alter corneal keratometry parameters and thus seems to be an astigmatically neutral procedure. However a slight, although seemingly transient, increase in CCT was observed after GDI implantation.

Tono-Pen versus Goldmann Applanation Tonometry: A Comparison of 898 Eyes

To compare the agreement in intraocular pressure (IOP) measurements obtained with the Tono-Pen (Reichert, Inc, Depew, NY) and Goldmann applanation tonometry (GAT). The influence of central corneal thickness (CCT) on IOP agreement between the 2 tonometry methods also was evaluated. Database study. A total of 898 patients from the Research, Innovation and Experimentation Database spanning 1999 through2016. A total of 898 IOP measurements of right eye obtained with GAT and the Tono-Pen were extracted from a glaucoma, glaucoma suspect, and ocular hypertension clinical database. The agreement between IOP measurements obtained by the 2 methods was analyzed using a Bland-Altman plot in Microsoft Excel (Microsoft, Redmond, WA). Their relationship to CCT was evaluated using linear regression analysis. Agreement between GAT and Tono-Pen measurements of IOP and influence of CCT on tonometry methods. The correlation between both tonometry devices was 0.76 (P < 0.001). The mean difference (Tono-Pen minus GAT) in IOP measurement was -0.15 mmHg (95% confidence limits, ±6.8 mmHg). The Tono-Pen underestimated GAT measurements at IOP of more than 16.8 mmHg and overestimated at IOP of less than 16.8 mmHg. Larger differences were associated with higher IOPs. An average difference of more than 3 mmHg by the Tono-Pen was observed for IOPs of 29 mmHg or more. A thicker cornea also was associated with higher IOP. A change of 0.16 mmHg for a 10-μm increase in CCT was appreciated for GAT, and one of 0.15 mmHg per 10 μm was appreciated for the Tono-Pen (all P < 0.001). In a large cohort of more than 898 measurements, the average difference between IOP measured by GAT and the Tono-Pen was less than 1 mmHg, although the limits of agreement were wide. Higher IOPs were associated with larger differences.

Comparative evaluation of femtosecond laser–assisted cataract surgery and conventional phacoemulsification in eyes with a shallow anterior chamber

To compare intraoperative performance and postoperative outcomes between femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification in eyes with a shallow anterior chamber (AC). Iladevi Cataract & IOL Research Centre, India. Prospective randomized masked clinical study. Patients undergoing cataract surgery with a shallow AC (<2.5mm) were randomized to have FLACS (Group 1, n=91) or conventional phacoemulsification (Group 2, n=91). Patients were followed up at 1day, 1week, and at 1, 3, and 6months. The primary outcome measure was central corneal thickness (CCT). The secondary outcome measures were corneal clarity, AC cells and flare, endothelial cell density (ECD), coefficient of variance, hexagonality, and uncorrected distance visual acuity (UDVA) at 1week. The study comprised 182 eyes (91 in each group) The cumulative dissipative energy was lower in the FLACS group (P<.05). The mean CCT was significantly lower with FLACS (540.40μm+49.40 [SD] vs 556+12.5μm, P=.03) at 1day and 1week (535.5+44.3μm vs 551+40.8μm, P=.04), with fewer eyes having higher than grade 2 AC cells and flare with FLACS (85% vs 72%, P=.056) at 1day and 1week (15% vs 28%, P=.03). At 1week, the UDVA was better with FLACS (0.089±0.31 logarithm of the minimum angle of resolution [logMAR] vs 0.178±0.65 logMAR, P=.042). At 6months, the reduction in ECD was lower in the FLACS group; however, the difference was not statistically significant. In eyes with shallow ACs, compared with conventional phacoemulsification, FLACS maintained clearer corneas, showed less increase in CCT, lower AC inflammation, and better UDVA in the early postoperative period.

Active-fluidics-based torsional phacoemulsification in diabetic eyes: A prospective interventional study.

Purpose:To compare the outcomes of active-fluidics based torsional phacoemulsification in diabetics and nondiabetics using a balanced tip.Methods:Two hundred and forty-eight patients undergoing senile cataract surgery using torsional phacoemulsification on an active-fluidics-based platform from December 2016 to August 2017 were included in this prospective, nonrandomized, interventional cohort study; of the 248 patients, 54 were controlled diabetics and 194 were nondiabetics. Intraoperative parameters such as cumulative dissipated energy (CDE), total ultrasound time, torsion usage time, torsion amplitude, aspiration time, and fluid usage were documented and compared. Endothelial cell loss (ECL) and central corneal thickness (CCT) were evaluated at 1 month postoperatively.Results:Diabetics and nondiabetics did not differ in CDE, total ultrasound time, torsion amplitude, aspiration time, fluid usage, endothelial cell count, and CCT. ECL on Day 1 (10.2 ± 8.0%) and Day 30 (11.05 ± 8.3%) were significantly higher in diabetics (P = 0.025 and P = 0.045, respectively). There was an increase in CCT on Day 1 (P = 0.018), which settled by Day 30. Grade 4 cataracts in diabetics had significantly higher CCT at Day 1 (P = 0.032) and Day 30 (P = 0.007). In the diabetic subgroup, Grades 3 and 4 cataracts required lower CDE (P < 0.001) and Grade 4 cataracts showed higher ECL than others till 1 month of follow-up (P < 0.05).Conclusion:Intraoperative and postoperative parameters after torsional phacoemulsification are comparable in diabetics and nondiabetics. Endothelial changes and pachymetry may be related to the grade of cataract in diabetics.

Risk factors for endothelial cell damage in diabetics after phacoemulsification.

BACKGROUND:To assess the corneal endothelium, central corneal thickness and the factors associated with endothelial cell damage after phacoemulsification in diabetics in comparison with non-diabeticsMETHODS:It was a case control study with 80 eyes each in the diabetic group and the control group. Intraoperative mydriasis, effective phaco time (EPT) and postoperative inflammation were measured. Preoperative, 1st week, 6th week and 3rd month postoperative endothelial cell density (ECD), coefficient of variation (CV), hexagonality and central corneal thickness (CCT) were also measured using Konan noncon robo specular microscope (Model - NSP 9900).RESULTS:In the control group, patients in the age group of 60-69 years were 3.8 times more at risk of ECL compared to patients in the age group of 50-59 years. Patients in whom EPT was ≥0.50 min, were 8.8 times more at risk of ECL when compared to patients in whom EPT <0.25 min. In the diabetic group, patients who had an inflammatory score of 1+ in the first postoperative week; also had 5.7 times more risk of ECL when compared to patients in whom the inflammatory score was 0.5+ in the first postoperative week. There was a significant increase in CV (p-0.03) and CCT (p-0.03), significant decrease in the hexagonality (p-0.01) and no statistically significant difference in the endothelial cell loss (ECL) (p-0.34) in diabetics after phacoemulsification when compared to controls.CONCLUSION:The present study reveals postoperative inflammation as a risk factor for ECL in diabetics and not intraoperative mydriasis and EPT.

A randomized controlled trial comparing femtosecond laser–assisted cataract surgery versus conventional phacoemulsification surgery

To compare the clinical results of conventional phacoemulsification surgery (CPS) with femtosecond laser-assisted cataract surgery. Guy's & St Thomas' NHS Foundation Trust, London, United Kingdom. Single-center prospective randomized interventional case-controlled trial. Patients undergoing cataract surgery were randomized to receive either CPS or femtosecond laser-assisted cataract surgery. The surgery was performed with a femtosecond laser (Lensx), and all operations were performed with a gravity-fluidics torsional phacoemulsification machine (Infiniti). The visual acuity, refraction, central corneal thickness (CCT), central foveal thickness (CFT), endothelial cell loss, and rates of intraoperative and postoperative events were recorded. Quality of life outcomes were measured with the EuroQOL 5 dimensions questionnaire (EQ-5D) and patient-reported quality of vision was assessed witha cataract surgery patient-reported outcome measures questionnaire (Cat-PROM5). The study comprised 400 eyes of 400 patients who had CPS (n=200) or femtosecond laser-assisted cataract surgery (n=200). Seven patients (3.5%) in the femtosecond laser-assisted group were not able to complete the treatment and received CPS. The mean uncorrected distance visual acuity (logarithm of the minimum angle of resolution [logMAR]) 0.15±0.21 (SD) and 0.15±0.19 logMAR after CPS and femtosecond laser-assisted surgery, respectively (P=1.0); the pinhole-corrected visual acuity was 0.04±0.12 and 0.04±0.12, respectively (P=1.0); the increase in CCT was 13±19μm and 15±25μm, respectively (P=.5); and the endothelial cell loss was 9.7±13.7 % and 10.2%±13.7, respectively (P=.76). The manifest refraction spherical equivalent error was -0.14±0.60 diopters (D) after CPS and -0.12±0.60 D after femtosecond laser-assisted surgery (P=.74); the mean change in CFT was 9±35μm and 6±35μm, respectively (P=.55); and the rate of posterior capsule rupture was 3% and 0%, respectively (P=.03). This study confirms the nonsignificant differences between 2 treatment modalities, notwithstanding a significant reduction in posterior capsule ruptures in the femtosecond laser-assisted surgery group.

Changes in corneal properties and its effect on intraocular pressure measurement following phacoemulsification with intraocular lens implantation with or without trabeculectomy

Purpose: To evaluate the changes incorneal biomechanical properties and their effect on pre and postoperative differences in IOP measurement by each tonometer&#x0D; Design: Observational study.&#x0D; Methods: The study was done in subjects who underwent phacoemulsification with intraocular lens (IOL) implantation (phaco-IOL) and combined phacoemulsification with IOL implantation and trabeculectomy (phaco-trab). IOP was measured by a single trained examiner using rebound tonometer (RBT), Ocular Response Analyzer (ORA), Goldmann applanation tonometer (GAT), dynamic contour tonometer (DCT), and Tono-Pen. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using ORA, central corneal thickness (CCT) using ultrasonic pachymeter, and corneal curvature (CR) with manual keratometry. All measurements were done one week prior to surgery and after four weeks and six weeks of the two surgeries, respectively. Only the operated eye was included for analysis.&#x0D; Results: Twenty-nine eyes of 29 normal subjects who underwent phaco-IOL and 23 eyes of 23 glaucoma subjects who underwent phaco-trab were studied. Increase in CCT [10.2 ± 14.86 microns, p = 0.001], decrease in CH [0.82 ± 1.38 mmHg, p = 0.003] and CRF [0.97 ± 1.0 mmHg, p &lt; 0.001] were found post-phaco-IOL, whereas post-phaco-trab decrease in CCT [16.61 ± 15.22 microns, p &lt; 0.001], CRF [2.28 ± 1.93 mmHg, p &lt; 0.001] with increase in CH [0.95 ± 1.89 mmHg, p = 0.03] were noted. Multiple linear regression analysis showed significant associations for change in CH and CRF with change in IOP and not with CCT and CR postoperatively.&#x0D; Conclusion: Alterations in CH and CRF were associated with changes in IOP measured postoperatively by different tonometers. CH and CRF changes contribute to postoperative changes in measured IOP.&#x0D;

Evaluation of Anterior Segment Parameters and Retinal Nerve Fiber Layer Thickness According to Pregnancy Trimester

Objective: To analyze the effects of pregnancy on anterior segment parameters and retinal nerve fiber layer (RNFL) thickness . Methods: The study designed prospectively conducted among 122 singleton pregnant women and 49 non-pregnant women. Intraocular pressure (IOP) was measured via the Goldman applanation tonometry. Central corneal thickness (CCT), axial lenght (AxL) and anterior chamber depth (ACD) measurement were performed with Echoscan US 500. For investigating the thickness of RNFL in detail, the optical coherence tomography was used. One Way ANOVA test was used to make a comparison between normal distribution groups. Results: There was no statistically significant difference regarding age. The IOP were 16.0 mmHg in the 1st trimester, 14.6 mmHg in the 2nd trimester, 13.6 mmHg in the 3rd trimester and 15.56 mmHg in the non-pregnant. Statistically, the findings of the 2nd and the 3rd trimester were significantly different from that of the 1st trimester (p = 0.033, p = 0.001, respectively). CCT averages were 554 μm, 564 μm and 552 μm, respectively, according to the trimester, while it was 542 μm in non-pregnant women. The difference between CCT averages between pregnancies in the 2nd and 3rd trimesters and non-pregnant women was statistically significant (p = 0.022, p = 0.041, respectively). The comparison of average thickness of four RNFL showed no difference between the pregnant and non-pregnant. Conclusion: During gestation, there was an increase in CCT with a decrease in IOP. We also determined that the ACD, AxL, and RNFL thickness measurements do not change with pregnancy.

Central Corneal Thickness Increase Due to Stromal Thickening With Diabetic Peripheral Neuropathy Severity.

To investigate the relationship between central corneal thickness (CCT) and diabetes disease severity among patients with diabetic peripheral neuropathy (DPN) compared with controls. In this cross-sectional study, 34 participants were examined. DPN status was assessed by clinical examination, nerve conduction studies, and quantitative sensory testing. All participants underwent comprehensive eye examination that included intraocular pressure measured by Goldmann applanation tonometry. CCT was measured by ultrasound pachymetry, and the thickness of corneal layers was assessed by corneal confocal microscopy. Association of CCT and DPN was examined using ANOVA. Among the 34 participants, there were 9 controls, 16 patients with mild DPN, and 9 patients with severe DPN. CCT was significantly increased in the DPN groups compared with controls (P = 0.0003). Mean CCT among controls was 552.7 ± 29.2 μm compared with 583.4 ± 25.0 μm in the mild DPN group and 613.3 ± 28.8 μm in the severe DPN group. In addition, stromal thickness differed significantly between the 3 study groups (P = 0.045). Mean stromal thickness among controls was 439.5 ± 23.5 μm compared with 478.9 ± 37.5 μm in the mild DPN group and 494.5 ± 39.1 μm in the severe DPN group. This study demonstrates that CCT increases with DPN severity because of an increase in stromal thickness. CCT increase associated with DPN has important clinical implications including glaucoma progression, keratoconus susceptibility, and intraocular pressure assessment and should be accounted for when evaluating patients with diabetes.

Effects of Corneal Hydration on Brillouin Microscopy In Vivo.

PurposeTo investigate how corneal hydration affects the Brillouin frequency of corneal stroma.MethodsFrom a simple analytical model considering the volume fraction of water in corneal stroma, we derived the dependence of Brillouin frequency on hydration and hydration-induced corneal thickness variation. The Brillouin frequencies of fresh ex vivo porcine corneas were measured as their hydration was varied in dextran solution and water. Healthy volunteers (8 eyes) were scanned in vivo repeatedly over the course of 9 hours, and the diurnal variations of Brillouin frequency and central corneal thickness (CCT) were measured.ResultsThe measured dependence of Brillouin frequency on hydration, both ex vivo and in vivo, agreed well with the theoretical prediction. The Brillouin frequencies of human corneas scanned immediately after waking were on average ∼25 MHz lower than their daytime average values. For stabilized corneas, the typical variation of Brillouin frequency was ± 7.2 MHz. With respect to CCT increase or swelling, the Brillouin frequency decreased with a slope of −1.06 MHz/μm in vivo.ConclusionsThe ex vivo and in vivo data agree with our theoretical model and support that the effect of corneal hydration on Brillouin frequency comes predominantly from the dependence of the tissue compressibility on the water. Corneal hydration correlates negatively with the Brillouin frequency. During daytime activities, the influence of physiological hydration changes in human corneas is < ± 10 MHz. The sensitivity to hydration may potentially be useful in detecting abnormal hydration change in patients with endothelial disorders.

Evaluation of central corneal thickness as measured by pentacam and retinal and choroidal thickness as measured by optical coherence tomography before and after uneventful cataract phacoemulsification in normal and diabetic patients without retinopathy

Introduction Cataract phacoemulsification surgery is the commonest ophthalmological surgical procedure performed worldwide. In spite of the relative short duration, small incision, and relative low power used during the procedure, it causes an inflammatory reaction, compression, and hypoxia to the tissues. Every step of this maneuver can cause direct effects on tissue and ocular pressure fluctuation, which may lead to disruption of the corneal endothelium, blood–aqueous barrier, and blood–retinal barrier, leading to postoperative corneal edema, increased macular, and choroidal thickness. Purpose The purpose of this study was to evaluate central foveal thickness (CFT) changes and subfoveal choroidal thickness (SFCT) changes using spectral domain optical coherence tomography and central corneal thickness (CCT) changes using Pentacam, before and after cataract surgery, and to compare the results between two groups, that is, normal and diabetic patients without retinopathy. Patients and methods A prospective study was conducted, in which 40 eyes of 40 patients, 20 nondiabetic and 20 diabetic without retinopathy, who underwent cataract phacoemulsification were examined preoperatively, 1 week postoperatively, and 1 month postoperatively. The study was done in Kobri El-Kobba Military Hospital during the period from May to November 2017. Results Preoperative CCT was significantly higher in diabetic group than the nondiabetic group. There was also a significant increase in CCT 1 week postoperatively in both group, reaching its peak, and then gradual decrease to near preoperative values 1 month postoperatively. There was no significant difference in preoperative and postoperative CFT values between the two groups. CFT continued to increase till 1 month postoperatively reaching values significantly higher than preoperative values at 1 week and 1 month postoperatively. The preoperative SFCT was significantly higher in diabetic group than the nondiabetic group with no significant differences in the postoperative values between the two groups; it also continued to increase till 1 month postoperatively, reaching values significantly higher than preoperative values at 1 week and 1 month postoperatively. Conclusion Cataract phacoemulsification leads to temporary increase in CCT and long-term increases in CFT and SFCT in both diabetic and nondiabetic patients. Diabetic patients have higher central corneal thickness and higher SFCT than nondiabetics.

Study of central corneal thickness (CCT) before and after small-incision cataract surgery (SICS) and phacoemulsification surgery

Purpose: To highlight the importance of measurement of central corneal thickness (CCT) which is an indirect indicator of corneal endothelial dysfunction after cataract surgery. Materials and Methods: This was a randomised control trial involving 101 patients who presented with cataract. Cataracts were graded using Lens Opacities Classification system grading. Fifty-one patients underwent small incision cataract surgery (SICS) and 50 underwent phacoemulsification (PHACO). Patients with any other ocular pathology were excluded. Results: There was significant improvement in the best corrected visual acuity (BCVA) comparable in both groups. There was a statistically significant increase in central corneal thickness on day 7th and 30th post op. The change in the CCT and BCVA was comparable between SICS and PHACO on day 30th post op. Conclusion: The increase in CCT suggests that there was some endothelial cell loss leading to change in corneal thickness but not to the extent of causing visual impairment. SICS and phacoemulsification surgery are comparable in respect to visual rehabilitation. Manual SICS is still a safe and cost-effective option in the developing world. Proper case selection, diligent surgery, and adequate postoperative care are essential to maintain a clear cornea.

Relationship between corneal biomechanical properties among pregnant women in a tertiary hospital in Nigeria.

In Nigeria, many pregnant women as well as health-care providers are unaware of the effect of pregnancy on the eye. The present study investigated the changes in central corneal thickness (CCT), corneal sensitivity (CS), and intraocular pressure (IOP) among pregnant women in a tertiary hospital in Nigeria and the relationship between them. A prospective longitudinal study was used. One hundred and thirty-four pregnant women attending the Obstetric Clinic of the University of Nigeria Teaching Hospital, Enugu, were consecutively recruited in their second trimester for the study. Changes in CCT, CS, and IOP were monitored at the second and third trimesters and 6-week postpartum. Data obtained were analyzed using Statistical Package for the Social Sciences version 20. The effect of duration of pregnancy on these variables was determined using simple linear regression and further analysis was done using Bonferroni's post hoc test. The women were aged 18-48 years, with a mean age of 30.81(±5.49) years and majority of them (61.2%) were multigravida. The duration of pregnancy varied inversely and significantly with CS (P < 0.05) and IOP (P < 0.000) with the least values recorded in the third trimester, while it varied directly and also significantly with CCT (P < 0.000) with the highest value obtained in the third trimester. A negative correlation that was significant only in third trimester was found between CCT and IOP (P < 0.02) and CS (P < 0.03). There was a progressive increase in CCT with a corresponding decrease in CS and IOP across the trimesters of pregnancy, but these changes reversed 6-week postpartum.