Comparison of central corneal thickness measurements with three new optical devices and a standard ultrasonic pachymeter

AIM:To compare the RTVue spectral optical coherence tomography(SD-OCT),Sirius Scheimpflug-Placido topographer,Lenstar optical low coherence reflectometry(OLCR)and ultrasound pachymetry(USP)devices in terms of their agreement and repeatability of measuring central corneal thickness(CCT).METHODS:In this prospective study,50 eyes of 50patients were included.Three repeated measures were obtained using SD-OCT,Scheimpflug-Placido topographer and USP and five measurements were determined with the OLCR.Bland-Altman plots were used to assess agreement among the instruments,and 95%limits of agreement(LoA)for each comparison were calculated.Intra-examiner repeatability was assessed using intraclass correlation coefficients(ICCs).RESULTS:The mean CCT by SD-OCT,ScheimpflugPlacido topographer,OLCR,and USP were 525.90±34.08μm,525.92±34.10μm,530.30±35.62μm,and543.50±37.11μm respectively.All 4 modalities of CCT measurements correlated closely with each other,with Pearson correlation coefficients ranging from 0.977 to0.995.The mean differences(and upper/lower LoA)for CCT measurements were-0.05±6.77μm(13.3/-13.3)between SD-OCT and Scheimpflug-Placido topographer,4.38±3.79μm(11.8/-3.1)between OLCR and SD-OCT,4.38±6.03μm(16.2/-7.5)between OLCR and ScheimpflugPlacido topographer,13.20±6.46μm(25.9/0.5)between USP and OLCR,17.59±6.76μm(30.8/4.3)between USP and SD-OCT,and 17.58±8.13μm(33.5/1.6)between USP and Scheimpflug-Placido topographer.Intra-examiner repeatability was excellent for all devices with ICCs】0.98.CONCLUSION:For most practical purposes,CCT measurements with the RTVue,Sirius and Lenstar can be used interchangeably.Although highly correlated,CCTmeasurement differences between USP and these 3optical instruments can be significant depending on the clinical situation.

Changes in intraocular pressure and central corneal thickness during pregnancy:a systematic review and Meta-analysis

AIM：To conduct a Meta-analysis for investigating the variations in intraocular pressure（IOP）and central corneal thickness（CCT）during normal pregnancy.METHODS：We searched for clinical trials published up to November 2015 without language or region restrictions in Pub Med,EMBASE,Web of Science,the Cochrane Central Register of Controlled Trials,Ovid,EBSCO,Elsevier,the Chinese Biomedicine Database,Wan Fang,CNKI,CQVIP and Google Scholar.Studies of the ocular changes observed in pregnant women were selected.The main outcomes were assessed by changes in IOP and CCT.RESULTS：Fifteen studies were included.In subgroup analyses,IOP was significantly decreased during the second MD=-1.53,95%CI（-2.19,-0.87）;P〈0.00001,and third MD=-2.91,95%CI（-3.74,-2.08）;P〈0.00001 trimesters of pregnancy.CCT was increased during the second MD=10.12,95%CI（2.01,18.22）;P=0.01,trimester of pregnancy;moreover,during the third trimester of pregnancy,the CCT displayed an increasing trend,but the difference was not significant MD=5.98,95%CI（-1.11,13.07）;P=0.1.CONCLUSION：A decrease in IOP is accompanied by an increase in CCT in the second and third trimesters of a normal pregnancy in women.

Corneal endothelial cell density and morphology and central corneal thickness in Guangxi Maonan and Han adolescent students of China

AIM: To investigate the corneal endothelial cell density and morphology and central corneal thickness in the Guangxi Maonan and Han adolescent students of China.METHODS: Noncontact specular microscope(Topcon SP3000 P, Tokyo, Japan) was performed in 133 adolescent students of Maonan nationality(M:F 54:79)and 105 adolescent students of Han nationality(M:F 50:55),5 to 20 y of age, who were randomly selected from 3schools in Huanjiang Maonan Autonomous County of Guangxi Zhuang Autonomous Region of China.Parameters studied included endothelial cell density,mean cell area, coefficient of variation in cell size,percentage hexagonality and central corneal thickness. RESULTS: Endothelial cell density, mean cell area,coefficient of variation in cell size, percentage hexagonality and central corneal thickness in the study population were(2969.50 ±253.93) cells/mm2,(339.23 ±29.44) μm2,(29.96 ±4.07) %,(64.58 ±9.41) % and(523.71 ±32.82) μm in Maonan and(2998.26 ±262.65) cells/mm2,(336.11±30.07) μm2,(29.89±5.03) %,(64.91±11.64) % and(524.39 ±33.15) μm in Han, respectively. No significant differences were observed in endothelial cell density,mean cell area, coefficient of variation in cell size,percentage hexagonality and central corneal thickness between Maonan and Han(P =0.615, 0.659, 0.528, 0.551,0.999). In Maonan and Han, we found age was negatively correlated with endothelial cell density and percentagehexagonality and positively correlated with mean cell area and coefficient of variation in cell size. Negative correlation was also found between central corneal thickness and age in Han, whereas no correlation was found in Maonan. CONCLUSION: There were no differences between Maonan and Han in corneal endothelial cell density and morphology and central corneal thickness. In these two nationalities, there were statistically significant decrease in endothelial cell density and percentage hexagonality with increasing age and statistically significant increase in cell area and coefficient of variation in cell size with increasing age. Central corneal thinned with increasing age in Han, whereas difference did not attain statistical significance in Maonan.

Central corneal thickness measurements in premature infants

AIM:To evaluate the central corneal thickness(CCT)measurements of premature infantsMETHODS:The premature infants who were born between 25-34wk of gestational age(GA)were retrieved for the study.All CCT measurements were performed within the first 2d of their life under topical anesthesia by using an ultrasonic pachymeter.RESULTS:The mean CCT of 200 eyes was 647.79±63.94μm.The mean CCT of the right and left eyes were similar(647.30±64.72μm and 648.29±63.47μm consecutively).The mean CCT of the girls was 642.08±54.89μm and the boys was 653.07±71.14μm,with no statistically significant difference(P】0.05).But there was a negative correlation of the CCT with GA and birth weight(BW)(P【0.01).CONCLUSION:The CCT values of premature babies were negatively correlated with GA and BW.

Measurement of central corneal thickness and precorneal tear film thickness of rabbits using the Scheimpflug system

AIMTo measure central corneal thickness (CCT) and pre-corneal tear film thickness using the Galilei dual-Scheimpflug analyzer (GSA) in New Zealand white rabbits.

Central Corneal Thickness in Adult Chinese

The central corneal thickness （CCT） in age 48 years or less of Chinese was characterized and its relationship with gender, age, refraction and intraocular pressure （IOP） was investigated. Right eyes of 1669 participants were included in this study （880 men, 52.7 % and 789 women, 47.3 %）. Mean age of the samples was 23.8±5.9 years. After the examination of corneal topography and refraction, Goldman applanation tonometry was carried out by one physician. Tonometric values were the mean of three consecutive readings. Subsequently, another physician carried out ultrasonic pachymetry with the DGH 2000 AP ultrasonic pachymeter. Six measurements were made at the center of the cornea of each eye. The mean value was used for analysis. The results showed that mean CCT of male participants was 551.33±34.62 μm, 5.79μm more than that of female participants. Linear regression analyses revealed that CCT was negatively related with age only in female and no association was found between refractive status and CCT. IOP was positively related to CCT, and there was a difference in IOP of 1.5 mmHg （1 mmHg=0. 133 kPa） per 100 μm difference in CCT. Ocular hypertension group was prone to have thicker cornea than average. The results indicated that in adult Chinese CCT tended to decrease with aging in female only. IOP measured by Goldmann tonometry was positively related with CCT so that CCT should be measured a- long with IOP.

Effect of silicone oil removal on central corneal thickness

AIM:To evaluate the effect of silicone oil removal(SOR) on central corneal thickness(CCT) in aphakic and pseudophakic eyes prospectively.· METHODS:Patients who underwent SOR surgery between June 2005-August 2007 were included in this study.Silicon oil was actively removed behind the posterior capsule through the pars plana sclerotomy site(posterior approach) in pseudophakic eyes and through the pupil and the corneal tunnel incision(anterior approach) in aphakic eyes with the 18-gauge cannula.CCT was assessed with Orbscan II corneal topography system preoperatively and at one month and three months postoperatively.A total of 34 eyes of 34 patients(26 males,8 females) comprised the study group.Mean age was(55.6±12.3) years(Range:25-80 years).Twenty-six eyes(76.5%) were pseudophakic and 8(23.5%) aphakic.Mean time between silicone oil injection and removal was(15.1±13.6) months(Range:5-54 months).At baseline,CCT was 576.4±46.0μm in pseudophakic eyes and 611.6±36.2μm in aphakic eyes.· RESULTS:At the first postoperative month CCT was(573.3±40.1)μm and(630.9±72.9)μm in pseudophakic and aphakic eyes respectively.At the third postoperative month,CCT was(582.7±49.5)μm and(614.5±82.4)μm in pseudophakic and aphakic eyes respectively.There was no statistically significant difference in CCT measurements one month and 3 months after SOR when compared to preoperative values in both aphakic and pseudophakic eyes(P> 0.05).· CONCLUSION:Active SOR either by anterior or posterior approach did not affect the CCT.·

Effect of 2% fluorescein on Scheimpflug central corneal thickness measurements

AIM： To assess central corneal thickness （CCT） changes measured with Scheimpflug device following instillation of 2% fluorescein in normal subjects. ~ METHODS： This was a prospective randomized study of 60 hospital volunteers. After baseline CCT measurements of both eyes of 40 subjects were obtained using Scheimpflug system, a drop of preservative-free 2% fluorescein, was instilled in one eye and in other eye, one drop of normal saline （control）. Measurements were repeated after 1, 2, 5, 10, 20, 30, 40, 50 and 60min （continuous assessment group）. Twenty subjects had baseline CCT taken, then fluorescein was instilled in one eye and measurements were taken at lmin. Ten eyes had saline rinse after lmin and 10 other eyes did not, measurements were repeated at 2min （eye rinse group）. RESULTS： The mean baseline CCT for continuous assessment group was 546.2±32.1um （range, 489.0-606.0）, control eyes was 546.6~±30.7 um （range, 489.0-602.0）. At lmin after fluorescein instillation, CCT significantly increased by 37.0±34.0um （P〈0.001）, then decreased gradually, reaching baseline at 60min. CCT variations were not significant in control group （P〉0.05）. For eye rinse group, CCT mean differences between baseline and 2min were 18.2um （95 % Ch -54.7 to 18.3） with rinse and 26.5um （95% CI： -62.9 to 9.9） without rinse; paired sample tests were not significant （P〉0.05）. CONCLUSION： The presence of fluorescein increased CCT value to a clinically relevant level of 6.8%. Eye rinse did not significantly reduce the effect at 2min post fluorescein timepoint.

Sirius Scheimpflug-Placido versus. ultrasound pachymetry for central corneal thickness: meta-analysis

Background:To compare the difference in central corneal thickness(CCT)measurements in normal eyes between a rotating Scheimpflug camera combined with a Placido-disk corneal topographer(Sirius,CSO,Italy)and ultrasound pachymetry(USP).Methods:A systematic literature search was conducted for relevant studies published on PubMed,Medline,EMBASE,and the Cochrane Library and ClinicalTrials.gov from inception to August 1st,2019.Primary outcome measures were CCT measurements between Sirius and USP.A random effects model was used to pool CCT measurements.Results:A total of twelve studies involving 862 eyes were included in this meta-analysis.The meta-analysis found CCT measurements between Sirius and USP to be statistically significantly different(P<0.0001).The mean difference between Sirius and USP was-11.26μm with a 95%confidence interval(CI)(-16.92μm,-5.60μm).The heterogeneity Was IP=60%(P=0.004).Conclusion:CCT measurements with the Sirius Scheimpflug-Placido topographer were statistically significantly lower than USP.However,it may be argued that the mean difference of 11.26μm is not a clinically significant difference.

Changes of corneal central thickness of aphakia following congenital cataract surgery under the first six months of life

AIM: To observe the central corneal thickness (CCT) changes in infants and young children who had been undergone bilateral congenital cataract surgery, and to compare the changes with normal control group which was selected from healthy population. METHODS: A cross section case-control study contained 28 cases (56 eyes) of bilateral aphakia (aphakic group) due to congenital cataract surgery combining with posterior continuous curvilinear capsulorhexis and with anterior vitrectomy during 2-6 months after birth. Fourteen children (28 eyes) of age-sex matched with the aphalic group were selected as normal control group. CCT and intraocular pressure (TOP) were measured postoperatively and the results were compared between groups. RESULTS: The mean CCT was 653.5 +/- 82.4 mu m in the aphakic group and 579.6 +/- 39.2 mu m in the control group, with a significant difference (P=0.000). The mean value of TOP in aphakic group (22.0 +/- 1.6mmHg) was greater than that of control group (16.9 +/- 2.1mmHg), P=0.023. There was a negative correlation between age and CCT in normal control group (r=-0.531, P=0.026), and there was no correlation in bilateral aphakia group (r=-0.324, P=0.165). CONCLUSION: Aphakic children due to congenital cataract surgery have a greater CCT than normal children. It is necessary to consider CCT in evaluating IOP for children after congenital cataract surgery.

Sirius Scheimpflug–Placido versus ultrasound pachymetry for central corneal thickness:meta-analysis

Background:To compare the difference in central corneal thickness(CCT)measurements in normal eyes between a rotating Scheimpflug camera combined with a Placido-disk corneal topographer(Sirius,CSO,Italy)and ultrasound pachymetry(USP).Methods:A systematic literature search was conducted for relevant studies published on PubMed,Medline,EMBASE,and the Cochrane Library and ClinicalTrials.gov from inception to August 1st,2019.Primary outcome measures were CCT measurements between Sirius and USP.A random effects model was used to pool CCT measurements.Results:A total of twelve studies involving 862 eyes were included in this meta-analysis.The meta-analysis found CCT measurements between Sirius and USP to be statistically significantly different(P<0.0001).The mean difference between Sirius and USP was−11.26μm with a 95%confidence interval(CI)(−16.92μm,−5.60μm).The heterogeneity was I^(2)=60%(P=0.004).Conclusion:CCT measurements with the Sirius Scheimpflug-Placido topographer were statistically significantly lower than USP.However,it may be argued that the mean difference of 11.26μm is not a clinically significant difference.

Difference in normal corneal thickness and curvature between Mongolian and Han nationalities

AIM: To investigate the differences in central corneal thickness(CCT) and curvature in myopic patients with different genders between Mongolian and Han nationalities in the Inner Mongolia region.METHODS: Patients with myopia, among whom 122cases(244 eyes) were Mongolian and 150 cases(300eyes) were Han, were selected. Pentacam was used to measure the corneal curvature, whereas CCT was determined by Pentacam, Orbscan and ultrasound pachymetry.RESULTS: Comparisons of the curvature of men and women in Mongolia showed a significant difference(P 【0.05) by comparing of the CCT values measured by three methods in Han and Mongolian in Inner Mongolia, we can draw a conclusion that the CCT values measured by Pentacam are less than the values by Orbscan and ultrasound pachymetry, and there are statistically significant difference in CCT measurement among the instruments except between the Orbscan and ultrasound pachymetry. The CCT values of Mongolians are more than Han people, and the analysis exhibited statistical significance. The CCT values measured by Orbscan in Mongolia of women are more than men, the difference showed statistical significance.CONCLUSION: Corneal curvature in Mongolian females was significantly higher than that in males. However, no significant difference was observed among Han males and females. The CCT values of Mongolian females were higher than those of males. The normal CCT values measured by Pentacam in Mongolian myopic patients were smaller than those obtained by Orbscan or ultrasound. The normal CCT values of Mongolian patients with myopia were higher than those reported for domestic people.

Manifestations of type 2 diabetes in corneal endothelial cell density,corneal thickness and intraocular pressure

We sought to evaluate central corneal thickness（CCT）,corneal endothelial cell density（ECD）and intraocular pressure（IOP）in patients with type 2 diabetes mellitus（DM）and to associate potential differences with diabetes duration and treatment modality in a prospective,randomized study.We measured ECD,CCT and IOP of125 patients with type 2 DM（mean age 57.1±11.5 years）and compared them with 90 age-matched controls.Measured parameters were analyzed for association with diabetes duration and glucose control modalities（insulin injection or oral medication）while controlling for age.In the diabetic group,the mean ECD（2511±252 cells/mm^2）,mean CCT（539.7±33.6μm）and mean IOP（18.3±2.5 mmHg）varied significantly from those the control group[ECD：2713±132 cells/mm^2（P〈0.0001）,CCT：525.0±45.3μm（P=0.003）and IOP：16.7±1.8 mmHg（P〈0.0001）].ECD was significantly reduced by about 32 cell/mm^2 for diabetics with duration of〉10 years when compared with those with duration of〈10 years（P〈0.05）.CCT was thicker and IOP was higher for diabetics with duration of〉10 years than those with duration of〈10 years（P〉0.05）.None of the measured parameters was significantly associated with diabetes duration and treatment modality（P〉0.05）.In conclusion,subjects with type 2DM exhibit significant changes in ECD,IOP and CCT,which,however,are not correlated with disease duration or if the patients receive on insulin injection or oral medications.

Blue-on-yellow perimetry and corneal thickness in patients with ocular hypertension

AIM: To evaluate the frequency of blue-on-yellow perimetry (B/YP) deficits in ocular hypertension (OHT) patients and to correlate these findings with central corneal thickness (CCT), and to investigate the influence of age, refraction and gender on the B/YP results in OHT patients. METHODS: The B/YP and CCT were checked respectively in 72 OHT patients with normal white-on-white perimetry (W/WP) and normal optic nerve head. The B/YP was tested by Octopus 101 automated perimetry using G2 strategy, while the CCT was checked with DGH-550 ultrasound pachymeter. All patients were chosen randomly one eye for statistical analysis, a binary regression model was used to determine the independent contribution of variables included in the model, and the differences of the intraocular pressure (TOP), CCT, age, refraction and gender between the normal B/YP group and abnormal B/YP group were compared. RESULTS: Forty-nine out of 72 patients with OHT showed normal B/YP results, whereas 23 of 72 patients (31.9%) demonstrated abnormal B/YP results. CCT showed a correlation with the B/YP results (B=-0.038, SE=0.019, P=0.044), whereas none of the TOP, age, refraction and gender was found to be correlated with the B/YP results. The mean CCT in OHT patients with abnormal B/YP group was lower than that with normal B/YP group (t=2.066, P=0.043). There was a significant positive correlation between TOP and CCT (R(2)=0.513, P=0.000). CONCLUSION: The mean CCT in OHT patients with abnormal B/YP results was lower than that with normal B/YP results. There was a significant positive correlation between TOP and CCT in OHT patients. The age, refraction and gender didn't influence the B/YP results in OHT patients.

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

AIM: To evaluate the impact of central corneal thickness(CCT) and corneal curvature on intraocular pressure(IOP) measurements performed by three different tonometers. METHODS: IOP in 132 healthy eyes of 66 participants was measured using three different tonometry techniques: Goldmann applanation tonometer(GAT), Pascal dynamic contour tonometer(DCT), and ICare rebound tonometer(RT). CCT and corneal curvature were assessed. RESULTS: In healthy eyes, DCT presents significantly higher values of IOP than GAT(17.34±3.69 and 15.27±4.06 mm Hg, P<0.0001). RT measurements are significantly lower than GAT(13.56±4.33 mm Hg, P<0.0001). Compared with GAT, DCT presented on average 2.51 mm Hg higher values in eyes with CCT<600 μm and 0.99 mm Hg higher results in eyes with CCT≥600 μm. The RT results were lower on average by 1.61 and 1.95 mm Hg than those obtained by GAT, respectively. Positive correlations between CCT in eyes with CCT<600 μm were detected for all IOP measurement techniques, whereas a similar relationship was not observed in eyes with thicker corneas. A correlation between IOP values and keratometry in the group with CCT<600 μm was not detected with any of the tonometry methods. In thicker corneas, a positive correlation was found for GAT and mean keratometry values(R=0.369, P=0.005). CONCLUSION: The same method should always be chosen for routine IOP control, and measurements obtained by different methods cannot be compared. All analysed tonometry methods are dependent on CCT;thus, CCT should be taken into consideration for both diagnostics and monitoring.

Comparison of corneal measurements in keratoconic eyes using rotating Scheimpflug camera and scanning-slit topography

AIM: To compare the anterior segment measurements obtained by rotating Scheimpflug camera(Pentacam) and Scanning-slit topography(Orbscan IIz) in keratoconic eyes.METHODS: A total of 121 patients, 71 males(58.7%)and 50 females(41.3%)(214 eyes) with the diagnosis of keratoconus(KC) were enrolled in this study. Following diagnosis of KC by slit-lamp biomicroscopic examination, central corneal thickness(CCT), thinnest corneal thickness(TCT), anterior chamber depth(ACD),and pupil diameter(PD) were measured by a single examiner using successive instrumentation by Pentacam and Orbscan.RESULTS: There was no significant difference between the two instruments for the measurement of CCT and TCT. In contrast, scanning-slit topography measured ACD(3.46±0.40 mm vs 3.38±0.33 mm, P =0.019) and PD(4.97 ±1.26 mm vs 4.08 ±1.19 mm, P 【0.001) significantly larger than rotating Scheimpflug camera.The two devices made similar measurements for CCT(95% CI:-2.94 to5.06, P =0.602). However, the mean difference for TCT was-6.28(95% CI:-10.51 to-2.06, P =0.004) showing a thinner measurement by Orbscan than by Pentacam. In terms of the ACD, the mean difference was 0.08 mm(95%CI: 0.04 to 0.12, P 【0.001) with Orbscan giving a slightly larger value than Pentacam. Similarly, Orbscan measurement for PD was longer than Pentacam(95% CI:0.68 to 1.08, P 【0.001).CONCLUSION: A good agreement was found between Pentacam and Orbscan concerning CCT measurement while comparing scanning-slit topography and rotatingScheimpflug camera there was an underestimation for TCT and overestimation for ACD and PD.

Comparing corneal outcome between femtosecond laser-assisted cataract surgery and conventional phaco surgery in Fuchs’endothelial dystrophy patients:a randomized pilot study with 6mo follow up

AIM:To compare the corneal outcome in Fuchs’endothelial dystrophy(FED)patients between femtosecond laser-assisted cataract surgery(FLACS)and conventional phaco surgery(CPS).METHODS:This was a randomized controlled study comparing one eye surgery by FLACS and the contralateral eye operated by CPS(stop and chop technique)in FED patients.Central corneal thickness,corneal light backscatter,corneal densitometry,and central corneal endothelial cell count and hexagonality(noncontact endothelial cell microscope),and corrected distance visual acuity(CDVA)were assessed preoperatively and at day 1,40,and 180 postoperatively.RESULTS:Totally 31 patients(16 women)were included.At day 40 postoperatively,the mean endothelial cell loss(ECL)was 23.67%by FLACS and 17.30%by CPS(P=0.53).At day 180 postoperatively,ECL was 25.58%in FLACS and 21.32%in CPS(P=0.69).Densitometry data in all layers and all annuli from anterior layer to posterior layer in annuli 0-2,2-6,6-10 and 10-12,total densitometry with all layers and all annuli was performed.A significant difference was found in 6-10(posterior layer)at day 1 with-1.42 grayscale units(GSU;95%CI:-2.66 to-0.19,P=0.02).In 10-12(anterior layer,central layer and all layers)at day 40 were significant different with 7.7(95%CI:1.89 to 13.50,P=0.009),3.97(95%CI:0.23 to 7.71,P=0.03),4.73 GSU(95%CI:0.71 to 8.75,P=0.02),respectively.In the remaining parameters we found no difference between the two groups(P>0.05).Three CPS eyes suffered from corneal decompensation.CONCLUSION:There is no significant difference in corneal outcome between FLACS and CPS.Endothelial cell density and pentacam corneal outcome may be inadequate as outcome parameters in FED patients.

Changes of lactate dehydrogenase in corneal edema after cataract surgery treated with trans-corneal oxygenation therapy

AIM:To investigate the changes in levels of the lactate dehydrogenase(LDH)enzyme in corneal edema after cataract surgery with trans-corneal oxygenation therapy.METHODS:This pre-post design study design conducted on 15 patients with corneal edema after cataract surgery and receiving trans-corneal oxygenation therapy.Tear sample(using Schirmer paper,from the inferior fornix of the conjunctiva)was carried out prior to trans-corneal oxygenation therapy,on the day 2(D2)and day 5(D5)postoperatively before and after trans-corneal oxygenation therapy.Visual acuity[VA(Log MAR)],corneal endothelial density,central corneal thickness(CCT),and coefficient of variation corneal endothelial(Co V)were recorded.The value of LDH was measured using ELISA.The difference in mean LDH value before and after trans-corneal oxygenation therapy,between two groups were analyzed using Wilcoxon signed rank test.RESULTS:There was a decrease in LDH tear concentration at D2(pre vs post:1127.54±497.09 vs 696.91±489.49;P=0.002)and D5(pre vs post:1064.17±677.77 vs 780.28±428.95;P=0.027)after trans-corneal oxygenation therapy as well as decrease in LDH concentration on the D2 compared to D5(P=0.041).The mean CCT was decreased significantly after the administration of trans-corneal oxygenation(pre vs post:632.10±25.66 vs 563.90±51.54;P=0.005).The mean VA and Co V increased significantly after the administration of trans-corneal oxygenation(P=0.001 and P=0.028,respectively).However,there was no difference in mean of corneal endothelial density(P=0.814).CONCLUSION:Trans-corneal oxygenation therapy is associated with significant decrease of tears LDH levels in post cataract surgery with corneal edema.It is accompanied by clinical improvement such as significant reduction of CCT.

Corneal properties in children with congenital isolated growth hormone deficiency

AIM:To compare the corneal parameters of children with congenital isolated growth hormone deficiency and healthy subjects.METHODS:In this cross-sectional,prospective study,50 cases with growth hormone(GH)deficiency treated with recombinant GH and 71 healthy children underwent a complete ophthalmic examination.The corneal hysteresis(CH),corneal resistance factor(CRF),Goldmann-correlated intraocular pressure(IOPg)and corneal-compensated intraocular pressure(IOPcc)were measured with the Ocular Response Analyzer(ORA).Central corneal thickness(CCT)was measured by a ultrasonic pachymeter.RESULTS:The mean age was 13.0±3.0 years in the GH deficiency group consisting of 21 females and 29 males and 13.4±2.4 years in the healthy children group consisting of 41 females and 30 males.There was no statistically significant difference between the groups for gender or age(Chi-square test,P=0.09;independent ttest,P=0.28,respectively).The mean duration of recombinant GH therapy was 3.8±2.4y in the study group.The mean CH,CRF,IOPg and IOPcc values were 11.0±2.0,10.9±1.9,15.1±3.3,and 15.1±3.2 mm Hg respectively in the study group.The same values were 10.7±1.7,10.5±1.7,15.2±3.3,and 15.3±3.4 mm Hg respectively in the control group.The mean CCT values were 555.7±40.6,545.1±32.5μm in the study and control groups respectively.There was no statistically significant difference between the two groups for CH,CRF,IOPg,IOPcc measurements or CCT values(independent t-test,P=0.315,0.286,0.145,0.747,0.13 respectively).CONCLUSION:Our study suggests that GH deficiency does not have an effect on the corneal parameters and CCT values.This observation could be because of the duration between the beginning of disease and the diagnosis and beginning of GH therapy.

Agreement of intraocular pressure measurement with Corvis ST,non-contact tonometer,and Goldmann applanation tonometer in children with ocular hypertension and related factors

AIM:To access the agreement of intraocular pressure(IOP)values obtained from biomechanically corrected tonometer[Corvis ST(CST)],non-contact tonometer(NCT),and Goldmann applanation tonometer(GAT)in children with NCT measured-IOP(NCT-IOP)values of 22 mm Hg or more,and related factors.METHODS:A total of 51 eyes with NCT-IOP≥22 mm Hg in children aged 7 to 14y were examined and IOP was measured by CST,NCT,and GAT.Based on GAT measured IOP(GAT-IOP),ocular hypertension(OHT)group(≥22 mm Hg,24 eyes)and the non-OHT group(<22 mm Hg,27 eyes)were defined.We compared the agreement of the three measurements,i.e.,CST measured IOP(CST-IOP),GAT-IOP,and NCT-IOP,and further analyzed the correlation between the differences in tonometry readings,central corneal thickness(CCT),axial length(AL),optic disc rim volume,and age.RESULTS:Compared with the OHT group,thicker CCT,larger rim volume,and higher differences between NCTIOP and GAT-IOP,were found in the non-OHT group.The differences between CST-IOP and GAT-IOP were lower than the differences between NCT-IOP and GAT-IOP in both groups.The mean differences in CST-IOP and GAT-IOP were 1.26 mm Hg(95%limit of agreement ranged from 0.1 to 2.41 mm Hg,OHT group)and 1.20 mm Hg(95%limit of agreement ranged from-0.5 to 3.00 mm Hg,non-OHT group),and the mean differences in NCT and GAT were 3.90 mm Hg(95%limit of agreement ranged from-0.19 to 9.70 mm Hg,OHT group)and 6.00 mm Hg(95%limit of agreement ranged from 1.50 to 10.50 mm Hg,non-OHT group).The differences between CST-IOP and GAT-IOP were not related to CCT,age,and AL in both groups;while the differences between NCT-IOP and GAT-IOP were related to CCT in the OHT group(r=0.93,P<0.001)and to CCT and AL in the non-OHT group(r=0.66,P<0.001,r=-0.81,P<0.001).CONCLUSION:The accuracy of NCT in the diagnosis of pediatric OHT is low.The agreement of CST-IOP and GATIOP was significantly higher in children with and without OHT than in those with NCT-IOP and GAT-IOP.Therefore,CST can be used as a good alternative for IOP measurement in children.The impacts of CCT and AL on NCT measurement need to be fully considered when managing childhood IOP.