Objective:To analyze the pathogenicity and clinical phenotype associated with a newly identified heterozygous variant in the ZEB1 gene that causes posterior pleomorphic corneal dystrophy (PPCD). Methods:A pedigree study was conducted.Clinical data of four people in 2 generations from one family with PPCD who visited Henan Eye Hospital in October 2023 were collected, including 3 patients. Relevant ophthalmic examinations were performed.Best corrected visual acuity, slit lamp microscopy, intraocular pressure, Pentacam corneal topography, Corvis ST corneal biomechanics analyzer, corneal endothelial microscopy, swept-source anterior segment coherence optical tomography (CASIA), laser scanning confocal microscopy, and ultra-wide-field fundus photography were performed to examine clinical phenotypes.Peripheral venous blood samples were collected from family members to extract genomic DNA, and whole exome sequencing was performed.Sanger sequencing and pedigree co-segregation analysis were carried out.Conservation analysis was performed using GERP+ + and Clustal Omega software, and the pathogenicity of the variant was assessed according to American College of Medical Genetics and Genomics (ACMG) guidelines.This study protocol adhered to the Declaration of Helsinki and was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2019[15]).All subjects or guardian signed informed consent.Results:This family conformed to autosomal dominant inheritance.Under a slit-lamp microscope, corneal endothelial vesicular lesions in both eyes could be seen in the proband, her father and her brother.Under a laser scanning confocal microscope, endothelial cells were missing at the lesions, and some were crater-like changes, and some lesions were circular or elliptical vesicular, and no other systemic abnormalities were observed.The ocular and physical examination of the proband's mother showed no abnormalities.Genetic testing results showed that the proband, her father and her brother all carried the ZEB1c.790G>A (p.Gly264Arg) heterozygous variant, but her mother did not carry the variantion.Sanger sequencing verified that this variantion was co-segregated within the family.The variantion is a newly discovered missense mutation that had not been reported in the Thousand Genomes Project, Genome Aggregation Database, and ExAC database.The prediction results of the variant by MutationTaster, SIFT, PROVEAN, VESST3, DANN, FATHMM-MKL, CADD, fitCons and other software were harmful, and GERP+ +, Weblogo, Clustal Omega analysis showed that the amino acids affected by the variant were highly conservative.According to the ACMG Guidelines, this variation was possible pathogenic.Conclusions:The identification of the missense mutation c. 790G>A (p.Gly264Arg) in the ZEB1 gene within this PPCD family provides new insights into the genetic basis of PPCD and the variant may be the pathogenic variant of in this family.

Objective:To evaluate the effect of toric collamer lens (TICL) rotation on myopia combined with astigmatism correction after V4c TICL implantation using standardized vector analysis.Methods:An observational case series study was performed.A total of 152 patients (268 eyes) who underwent V4c TICL implantation for the correction of myopia and myopic astigmatism were enrolled at Henan Eye Hospital from January to December 2021.The preoperative spherical diopter, cylindrical diopter, and spherical equivalent (SE) were -15.00 to -3.25 D, -5.00 to -0.50 D, -16.50 to -3.88 D, respectively.Postoperative TICL vault and axis were measured by anterior segment optical coherence tomography, and postoperative TICL rotation was calculated.Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), spherical diopter, cylindrical diopter, SE, and target astigmatism vector were recorded before and 1 month after surgery.The effectiveness index, safety index, surgically induced astigmatism vector (SIA), margin of error (ME), absolute value of the difference vector |DV|, correction index (CI), and achievement index (IS) were calculated based on the subjective refraction results 1 month after surgery and the cylindrical axis of the V4c TICL.Vector analysis parameters was compared among patients with different preoperative astigmatism, intraoperative TICL fixation, postoperative TICL rotation, and postoperative vault.The correlation between postoperative TICL rotation and TICL fixed angle deviation, postoperative vault, visual acuity and refraction, and vector analysis parameters were evaluated.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2021[13]).Written informed consent was obtained from each subject.Results:At 1 month postoperatively, the mean safety and efficacy indices were 1.27 and 1.29, respectively.There was no statistically significant difference between the predicted SE of (-0.11±0.13)D and the postoperative SE of (-0.07±0.52)D ( t=-0.994, P=0.321).UCVA, BCVA and cylinder diopter in the operative eyes were all improved after surgery compared to before surgery and the differences were statistically significant ( t=17.854, 5.446, -25.634; all P<0.001).The rotation of V4c TICL was 0° to 25°, with a mean of (5.41±4.35)°, which was positively correlated with the V4c TICL fixed angle deviation ( rs=0.461, P<0.001), negatively correlated with postoperative cylindrical diopter and positively correlated with postoperative UCVA, |DV| and SIA ( r=-0.360, 0.191, 0.205, 0.142; all P<0.05).Vector analysis between groups showed that vault, SIA and |DV| were higher and CI and IS were lower in low astigmatism group than in high astigmatism group ( Z=-3.017, -13.569, -2.793, -2.761, -4.779; all P<0.05).V4c TICL rotation and |DV| were lower in low fixation angle difference group than in high fixation angle difference group ( Z=-7.865, -2.080; both P<0.05).Preoperative cylindrical diopter, intraoperative V4c TICL fixed angle deviation, SIA and |DV| were lower in low rotation group than in high rotation group ( Z=-2.104, -4.578, -2.456, -2.090; all P<0.05).There were no statistically significant differences in the TICL rotation or in each vector between patients with different vault after the surgery (all P>0.05). Conclusions:V4c TICL implantation can achieve good results for the correction of myopia and myopic astigmatism.There is a slight difference between the fixation axis and the target axis of V4c TICL, which affects the rotation of V4c TICL and |DV|.Postoperative V4c TICL rotation is related to TICL fixed angle deviation, postoperative UCVA, SIA, |DV| and postoperative cylindrical diopter.Postoperative vault has no significant effect on TICL rotation and differences in each vector.

Objective:To evaluate the repeatability of anterior segment biometry measurements obtained using ultrasound biomicroscopy (UBM) and the ArcScan Insight 100, and to compare the agreement between the two devices.Methods:A cross-sectional study was conducted.Seventy myopic patients (70 eyes) who underwent V4c implantable collamer lens implantation at Henan Eye Hospital from March to May 2023 were included.The ArcScan Insight 100 and UBM were used to measure the following parameters three times: angle-to-angle distance (ATA), sulcus-to-sulcus distance (STS), anterior chamber depth (ACD), crystalline lens rise (CLR), anterior chamber width (ACW), ciliary body inner diameter (CBID), anterior chamber angle (ACA), trabecular-ciliary angle (TCA) and maximum ciliary body thickness (CBTmax). The repeatability of anterior segment biological measurements obtained using the two devices was assessed by intraclass correlation coefficient (ICC). The consistency between the two instruments was evaluated by Bland-Altman consistency test.This study complied with the Declaration of Helsinki and was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2021[13]). All patients understood the purpose and significance of this study and signed the informed consent form.Results:The repeatability of ATA, STS, ACD, CLR, ACW, CBID, ACA, TCA and CBTmax measured by UBM and ArcScan Insight 100 was good (all ICC>0.9). There was no significant difference in ACD, ACW, and ACA between the two instruments ( t=0.696, -1.025, -1.447; all P>0.05). ATA, STS, CLR and CBID measured by UBM were lower and TCA and CBTmax were higher than those measured by UBM ArcScan Insight 100, and the differences were statistically significant ( t=-8.586, -12.551, -4.481, -4.420, 4.535, 7.812; all P<0.05). The differences of ATA, STS, ACD, CLR, ACW, CBID and CBTmax between UBM and ArcScan Insight 100 were 0.38, 0.47, -0.01, 0.07, 0.3, 0.26 and -0.21 mm, respectively, with the 95% limits of agreement (LoA) of (-0.34, 1.10), (-0.15, 1.09), (-0.28, 0.26), (-0.20, 0.35), (-0.33, 0.93), (-0.71, 1.23) and (-0.64, 0.23)mm, respectively, which showed good coherence.The differences in ACA and TCA measurements were 2.26° and -7.81°, respectively, and the 95%LoA values were (-23.36°, 27.89°) and (-36.05°, 20.43°), respectively, with poor coherence.There was a strong positive correlation in ACD measurements measured by UBM and ArcScan Insight 100 ( r=0.827, P<0.05). There were moderate positive correlations in ATA, STS, CLR, ACW and CBID ( r=0.678, 0.749, 0.617, 0.765, 0.519; all P<0.05). There was no significant correlation in ACA, TCA and CBTmax ( r=0.270, 0.032, 0.178; all P>0.05). Conclusions:The repeatability of ArcScan Insight 100 and UBM in measuring anterior segment biological parameters is good.However, the consistency of ACA, TCA and CBTmax measured by the two instruments is poor and may be affected by self-regulation of the body.ATA, STS, ACD, CLR, ACW and CBID have good consistency and can be used interchangeably.

Objective:To analyze the pathogenicity and clinical phenotype associated with a newly identified heterozygous variant in the ZEB1 gene that causes posterior pleomorphic corneal dystrophy (PPCD). Methods:A pedigree study was conducted.Clinical data of four people in 2 generations from one family with PPCD who visited Henan Eye Hospital in October 2023 were collected, including 3 patients. Relevant ophthalmic examinations were performed.Best corrected visual acuity, slit lamp microscopy, intraocular pressure, Pentacam corneal topography, Corvis ST corneal biomechanics analyzer, corneal endothelial microscopy, swept-source anterior segment coherence optical tomography (CASIA), laser scanning confocal microscopy, and ultra-wide-field fundus photography were performed to examine clinical phenotypes.Peripheral venous blood samples were collected from family members to extract genomic DNA, and whole exome sequencing was performed.Sanger sequencing and pedigree co-segregation analysis were carried out.Conservation analysis was performed using GERP+ + and Clustal Omega software, and the pathogenicity of the variant was assessed according to American College of Medical Genetics and Genomics (ACMG) guidelines.This study protocol adhered to the Declaration of Helsinki and was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2019[15]).All subjects or guardian signed informed consent.Results:This family conformed to autosomal dominant inheritance.Under a slit-lamp microscope, corneal endothelial vesicular lesions in both eyes could be seen in the proband, her father and her brother.Under a laser scanning confocal microscope, endothelial cells were missing at the lesions, and some were crater-like changes, and some lesions were circular or elliptical vesicular, and no other systemic abnormalities were observed.The ocular and physical examination of the proband's mother showed no abnormalities.Genetic testing results showed that the proband, her father and her brother all carried the ZEB1c.790G>A (p.Gly264Arg) heterozygous variant, but her mother did not carry the variantion.Sanger sequencing verified that this variantion was co-segregated within the family.The variantion is a newly discovered missense mutation that had not been reported in the Thousand Genomes Project, Genome Aggregation Database, and ExAC database.The prediction results of the variant by MutationTaster, SIFT, PROVEAN, VESST3, DANN, FATHMM-MKL, CADD, fitCons and other software were harmful, and GERP+ +, Weblogo, Clustal Omega analysis showed that the amino acids affected by the variant were highly conservative.According to the ACMG Guidelines, this variation was possible pathogenic.Conclusions:The identification of the missense mutation c. 790G>A (p.Gly264Arg) in the ZEB1 gene within this PPCD family provides new insights into the genetic basis of PPCD and the variant may be the pathogenic variant of in this family.

Objective:To evaluate the effect of toric collamer lens (TICL) rotation on myopia combined with astigmatism correction after V4c TICL implantation using standardized vector analysis.Methods:An observational case series study was performed.A total of 152 patients (268 eyes) who underwent V4c TICL implantation for the correction of myopia and myopic astigmatism were enrolled at Henan Eye Hospital from January to December 2021.The preoperative spherical diopter, cylindrical diopter, and spherical equivalent (SE) were -15.00 to -3.25 D, -5.00 to -0.50 D, -16.50 to -3.88 D, respectively.Postoperative TICL vault and axis were measured by anterior segment optical coherence tomography, and postoperative TICL rotation was calculated.Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), spherical diopter, cylindrical diopter, SE, and target astigmatism vector were recorded before and 1 month after surgery.The effectiveness index, safety index, surgically induced astigmatism vector (SIA), margin of error (ME), absolute value of the difference vector |DV|, correction index (CI), and achievement index (IS) were calculated based on the subjective refraction results 1 month after surgery and the cylindrical axis of the V4c TICL.Vector analysis parameters was compared among patients with different preoperative astigmatism, intraoperative TICL fixation, postoperative TICL rotation, and postoperative vault.The correlation between postoperative TICL rotation and TICL fixed angle deviation, postoperative vault, visual acuity and refraction, and vector analysis parameters were evaluated.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2021[13]).Written informed consent was obtained from each subject.Results:At 1 month postoperatively, the mean safety and efficacy indices were 1.27 and 1.29, respectively.There was no statistically significant difference between the predicted SE of (-0.11±0.13)D and the postoperative SE of (-0.07±0.52)D ( t=-0.994, P=0.321).UCVA, BCVA and cylinder diopter in the operative eyes were all improved after surgery compared to before surgery and the differences were statistically significant ( t=17.854, 5.446, -25.634; all P<0.001).The rotation of V4c TICL was 0° to 25°, with a mean of (5.41±4.35)°, which was positively correlated with the V4c TICL fixed angle deviation ( rs=0.461, P<0.001), negatively correlated with postoperative cylindrical diopter and positively correlated with postoperative UCVA, |DV| and SIA ( r=-0.360, 0.191, 0.205, 0.142; all P<0.05).Vector analysis between groups showed that vault, SIA and |DV| were higher and CI and IS were lower in low astigmatism group than in high astigmatism group ( Z=-3.017, -13.569, -2.793, -2.761, -4.779; all P<0.05).V4c TICL rotation and |DV| were lower in low fixation angle difference group than in high fixation angle difference group ( Z=-7.865, -2.080; both P<0.05).Preoperative cylindrical diopter, intraoperative V4c TICL fixed angle deviation, SIA and |DV| were lower in low rotation group than in high rotation group ( Z=-2.104, -4.578, -2.456, -2.090; all P<0.05).There were no statistically significant differences in the TICL rotation or in each vector between patients with different vault after the surgery (all P>0.05). Conclusions:V4c TICL implantation can achieve good results for the correction of myopia and myopic astigmatism.There is a slight difference between the fixation axis and the target axis of V4c TICL, which affects the rotation of V4c TICL and |DV|.Postoperative V4c TICL rotation is related to TICL fixed angle deviation, postoperative UCVA, SIA, |DV| and postoperative cylindrical diopter.Postoperative vault has no significant effect on TICL rotation and differences in each vector.

Objective:To evaluate the repeatability of anterior segment biometry measurements obtained using ultrasound biomicroscopy (UBM) and the ArcScan Insight 100, and to compare the agreement between the two devices.Methods:A cross-sectional study was conducted.Seventy myopic patients (70 eyes) who underwent V4c implantable collamer lens implantation at Henan Eye Hospital from March to May 2023 were included.The ArcScan Insight 100 and UBM were used to measure the following parameters three times: angle-to-angle distance (ATA), sulcus-to-sulcus distance (STS), anterior chamber depth (ACD), crystalline lens rise (CLR), anterior chamber width (ACW), ciliary body inner diameter (CBID), anterior chamber angle (ACA), trabecular-ciliary angle (TCA) and maximum ciliary body thickness (CBTmax). The repeatability of anterior segment biological measurements obtained using the two devices was assessed by intraclass correlation coefficient (ICC). The consistency between the two instruments was evaluated by Bland-Altman consistency test.This study complied with the Declaration of Helsinki and was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2021[13]). All patients understood the purpose and significance of this study and signed the informed consent form.Results:The repeatability of ATA, STS, ACD, CLR, ACW, CBID, ACA, TCA and CBTmax measured by UBM and ArcScan Insight 100 was good (all ICC>0.9). There was no significant difference in ACD, ACW, and ACA between the two instruments ( t=0.696, -1.025, -1.447; all P>0.05). ATA, STS, CLR and CBID measured by UBM were lower and TCA and CBTmax were higher than those measured by UBM ArcScan Insight 100, and the differences were statistically significant ( t=-8.586, -12.551, -4.481, -4.420, 4.535, 7.812; all P<0.05). The differences of ATA, STS, ACD, CLR, ACW, CBID and CBTmax between UBM and ArcScan Insight 100 were 0.38, 0.47, -0.01, 0.07, 0.3, 0.26 and -0.21 mm, respectively, with the 95% limits of agreement (LoA) of (-0.34, 1.10), (-0.15, 1.09), (-0.28, 0.26), (-0.20, 0.35), (-0.33, 0.93), (-0.71, 1.23) and (-0.64, 0.23)mm, respectively, which showed good coherence.The differences in ACA and TCA measurements were 2.26° and -7.81°, respectively, and the 95%LoA values were (-23.36°, 27.89°) and (-36.05°, 20.43°), respectively, with poor coherence.There was a strong positive correlation in ACD measurements measured by UBM and ArcScan Insight 100 ( r=0.827, P<0.05). There were moderate positive correlations in ATA, STS, CLR, ACW and CBID ( r=0.678, 0.749, 0.617, 0.765, 0.519; all P<0.05). There was no significant correlation in ACA, TCA and CBTmax ( r=0.270, 0.032, 0.178; all P>0.05). Conclusions:The repeatability of ArcScan Insight 100 and UBM in measuring anterior segment biological parameters is good.However, the consistency of ACA, TCA and CBTmax measured by the two instruments is poor and may be affected by self-regulation of the body.ATA, STS, ACD, CLR, ACW and CBID have good consistency and can be used interchangeably.

Objective:To evaluate the consistency of the Chinese three-dimensional anterior visual field analysis system (Scansys), the anterior segment analyzer (Pentacam), the frequency-domain anterior segment optical coherence tomography system (CASIA SS-1000), and a new ultra-high frequency digital ultrasound scanning system (Arcscan Insight100) to measure central vault after implantable collamer lens (ICL) implantation in myopic eyes with crystalline lenses.Methods:A diagnostic test study was conducted.Fifty-six myopic patients (56 eyes) who underwent ICL V4c implantation from June to December 2019 were included.Scansys, Pentacam, CASIA and Arcscan were used to measure the central vault after surgery.The vault measurements were compared.Correlations between the measurements of the four instruments were analyzed using Pearson correlation analysis, and consistency comparisons were analyzed using the Bland-Altman method.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2021[13]). Written informed consent was obtained from each subject.Results:The central vault measurements by Scansys, Pentacam, CASIA and Arcscan were (481.8±191.6), (476.4±190.6), (619.3±207.5) and (534.0±221.2)μm, respectively, with a statistically significant overall difference ( F=143.301, P<0.001). The vault measurements by Scansys and Pentacam were significantly lower than CASIA and Arcscan, and Arcscan was lower than CASIA, with statistically significant differences (all at P<0.001). There were strong positive correlations in vault measurements between Arcscan and CASIA, Arcscan and Pentacam, Arcscan and Scansys, CASIA and Pentacam, CASIA and Scansys, Pentacam and Scansys ( r=0.982, 0.933, 0.931, 0.942, 0.941, 0.989; all at P<0.001). Intraclass correlation coefficients of vault measurements by Scansys, Pentacam, CASIA and Arcscan were 0.985, 0.975, 0.998, 0.992, respectively.The 95% limits of agreement of vault measurements differences were -170 to 0, 0 to 280, 0 to 280, -110 to 210, -100 to 220 μm, between CASIA and Arcscan, CASIA and Scansys, CASIA and Pentacam, Arcscan and Scansys, Arcscan and Pentacam, respectively, and the maximum absolute value of the difference was beyond the clinically acceptable range, showing poor agreement.The 95% limits of agreement of vault measurement difference was -60 to 50 μm between Scansys and Pentacam, showing a good agreement. Conclusions:The repeatability of the vault after ICL V4c implantation in myopic eyes measured by the four instruments is good.Among them, the vault measurements of Scansys and Pentacam are smaller, showing good consistency, and their results could be substituted for each other.The measurement of CASIA is the largest, followed by Arcscan, which have a large difference from each other, and their results can not be substituted for each other, which should be comprehensively analyzed with the actual situation in clinical work.

Objective:To investigate the clinical characteristics of patients with keratoconus, and to explore the factors influencing keratoconus severity.Methods:A cross-sectional study was performed.A total of 908 patients (1 476 eyes) with primary keratoconus were enrolled in Henan Eye Hospital from January 2019 to December 2021.The medical history data of patients were collected by face-to-face questionnaire survey.Refractive parameters were measured by subjective optometry.Intraocular pressure (IOP) was measured by a non-contact tonometer, and corrected IOP was calculated by Dresden formula.Corneal topography parameters was obtained using Pentacam HR.The subgroup analysis of clinical characteristics of all patients was performed by age (<21 years, 21~<31 years, ≥31 years) and gender.Disease severity was graded based on steep keratometry (Ks), namely mild (Ks<48 D), moderate (48 D≤Ks<55 D) and severe (Ks≥55 D). The influencing factors of disease severity in keratoconus were analyzed by ordered Logistic regression.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2019[5]). All subjects or guardians were informed of the purpose and significance of the study and written informed consent was obtained.Results:Of the 908 patients, 622 were with bilateral keratoconus and 286 were with unilateral keratoconus.The median age of onset was 20(17, 26) years, and the median age of diagnosis was 21(18, 27) years.The ratio of males to females was 3.05∶1.There were 9.80%(89/908) of the patients having a history of allergy, 25.55%(232/908) having a history of other systemic diseases, and 1.98%(18/908) having a family history of keratoconus.Of the 1 476 affected eyes, 27.57%(407/1 476) were diagnosed as severe keratoconus, and 61.94%(568/917) had a history of eye rubbing.The medians of sphericity, cylindricity, IOP, corrected IOP, Ks, thinnest corneal thickness (TCT), anterior corneal surface elevation (AE) and posterior corneal surface elevation (PE) were -4.00(-7.00, -1.75)D, -3.50(-6.00, -1.50)D, 12.00(10.30, 13.80)mmHg, 15.40(13.60, 17.00)mmHg, 49.85(46.40, 54.90)D, 460.00(425.00, 490.00)μm, 21.00(13.00, 34.75)μm, 51.00(33.00, 75.00)μm, respectively.The spherical refraction, IOP and corrected IOP were lower and the cylindrical refraction was higher in patients at age <21 years than in patients at age 21~<31 years, and the TCT of patients at age <21 years was higher than that at age ≥31 years, and the differences were statistically significant (all at P<0.05). Compared with female patients, male patients had younger onset age, lower spherical refraction, IOP and corrected IOP, as well as higher cylindrical refraction, AE and PE, showing statistically significant differences (all at P<0.05). The spherical refraction and IOP of male patients were lower than those of female patients at age <21 years, and the cylindrical refraction was higher in males than in females among the patients at age 21~<31 years, and the differences were statistically significant (both at P<0.05). Among the patients with onset age <21 years and diagnosis age <21 years, the ratio of males to females in patients with severe keratoconus was higher than those with mild and moderate disease, and the difference was statistically significant (both at P<0.05). Older age of onset was a protective factor for disease severity in keratoconus (odds ratio=0.981, 95% confidence interval: 0.963~0.999). Conclusions:The younger the onset age of keratoconus patients, the more severe the disease.Among the patients with severe keratoconus, there were more male patients, and males have a younger onset age and severer conditions.It is suggested that early screening of keratoconus in children and adolescents should be strengthened in clinical work, and more active prevention and treatment measures should be taken for younger patients, especially males.

Objective:To investigate the differences in corneal thickness and corneal epithelial thickness measurements by two kinds of high-resolution frequency domain anterior segment optical coherence tomography (OCT), RTVue XR-OCT and Cirrus 5000 HD-OCT, and to analyze the consistency between them.Methods:A cross-sectional study was conducted.Fifty-two patients (52 eyes) who were admitted to Henan Eye Hospital from July to September 2019 were enrolled.The corneal thickness and corneal epithelial thickness in various areas including the central area (C area) (2-mm diameter), and 8 concentric corneal areas of 2 to 5-mm diameter, which were the superior area (S area), the superior nasal (SN area), the nasal side area (N area), the inferior nasal area (IN area), the inferior area (I area), the inferior temporal area (IT area), the temporal area (T area) and the superior temporal area (ST area) above the temporal, were measured by the same examiner using RTVue XR-OCT and Cirrus 5000 HD-OCT.The corneal thickness and corneal epithelial thickness measurements were compared to analyze the difference, correlation and consistency between the two kinds of OCT.This study adhered to the Declaration of Helsinki.The study protocol was approved by an Ethics Committee of Henan Eye Hospital (No.HNEECKY-2021[06]). Written informed consent was obtained from each subject prior to any medical examination.Results:The corneal thickness measured by RTVue XR-OCT in C, S, SN, N, IN, I, IT, T, ST areas were (521.73±29.85), (554.31±32.38), (553.54±33.30), (546.96±32.05), (537.54±32.10), (532.13±31.51), (528.42±30.38), (532.25±30.08), (544.85±30.70)μm, respectively, and the corneal thickness in the 9 areas measured by Cirrus 5000 HD-OCT were (526.77±30.62), (555.13±33.32), (558.08±32.57), (554.46±31.42), (548.29±31.84), (539.69±32.74), (536.19±32.40), (533.38±31.90), (543.83±32.02)μm, respectively.There was no significant difference in corneal thickness of various areas between the two kinds of OCT (all at P>0.05), and there were positive correlations between them ( r=0.99, 0.89, 0.95, 0.97, 0.95, 0.93, 0.96, 0.97, 0.92; all at P<0.01). Bland-Altman analysis showed that there was a good consistency of corneal thickness measurements by the two kinds of OCT.The corneal epithelial thickness in C, S, SN, N, IN, I, IT, T, ST areas measured by RTVue XR-OCT were (52.06±3.26), (52.58±3.48), (53.06±3.56), (53.75±3.49), (53.81±3.40), (53.48±3.35), (52.96±3.32), (52.67±3.19), (53.12±3.15) μm, respectively, and the corneal epithelial thickness in the 9 areas measured by Cirrus 5000 HD-OCT were (46.75±3.25), (47.40±3.36), (47.58±3.64), (48.85±4.48), (48.46±4.54), (48.40±4.96), (48.06±5.12), (47.46±3.91), (48.79±3.90)μm, respectively.There were statistically significant differences in the corneal epithelial thickness of various areas measured by the two kinds of OCT (all at P<0.05), and there was no significant correlation between them ( r=0.17, 0.08, 0.16, 0.28, 0.20, 0.24, 0.19, 0.21, 0.13; all at P>0.05). Bland-Altman analysis showed poor consistency of corneal epithelial thickness measurements between the two kinds of OCT. Conclusions:There is no significant difference in measuring corneal thickness between the two kinds of OCT and the consistency is high, which means that they can be replaced by each other.There are significant differences in corneal epithelial thickness measurement between them and the consistency is poor, so they are not interchangeable.

Objective:To compare the accuracy and stability between corneal topography-guided femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE) for myopic astigmatism by vector analysis.Methods:A non-randomized controlled clinical trial was performed.One hundred and twenty patients (214 eyes) with myopic astigmatism who underwent the FS-LASIK or SMILE in Henan Eye Hospital from January 2020 to July 2020 were enrolled.The patients were divided into FS-LASIK group (58 cases, 105 eyes) and SMILE group (62 cases, 109 eyes) according to different surgeries.The visual acuity, refraction, intraocular pressure and corneal topography were examined before and 1 week, 1 month and 3 months after operation.The results of vector analysis between the two groups were compared, including target induced astigmatism vector (TIA), surgically induced astigmatism vector (SIA), magnitude of error (ME), angle of error (|AE|), difference vector (|DV|), correction index (CI), and index of success (IOS) 3 months after operation.This study protocol adhered to the Declaration of Helsinki and was approved by an Ethics Committee of Henan Eye Hospital (No.HNEECKY-2020[25]). Written informed consent was obtained from each patient before operation.Results:Three months after surgery, no astigmatism was found in 11 eyes (10.5%), and with the rule (WTR) astigmatism was in 23 eyes (21.9%), and against the rule (ATR) and oblique astigmatism were in 71 eyes (67.6%) in FS-LASIK group.In SMILE group, no astigmatism was detected in 35 eyes (32.1%), and WTR astigmatism was in 58 eyes (53.2%), and ATR and oblique astigmatism were in 16 eyes (14.7%), showing a statistically significant difference between them ( χ2 =48.20, P<0.05). The postoperative SIA, |AE|, |DV|, CI and IOS values in the SMILE group were lower than those in the FS-LASIK group, showing statistically significant differences between them (all at P<0.05). The ME was -0.20 (-0.37, 0.00)D in FS-LASIK group and 0.20 (0.00, 0.25)D in SMILE group.Within 3 months after operation, there was no significant difference in ME among different time points in the FS-LASIK group (all at P>0.05) and in spherical equivalent (SE) among different time points in the SMILE group (all at P>0.05). There was significant difference in the results of vector analysis among different time points in the two groups (all at P<0.05). Conclusions:Both FS-LASIK and SMILE are effective in the correction of myopic astigmatism.Astigmatism is slightly overcorrected by FS-LASIK and slightly undercorrected by SMILE.The axial error is smaller and the SE is more stable after SMILE within 3 months postoperatively.