ABSTRACT
Objective:To investigate the alteration of m6A demethylase AlkB homolog 5 (ALKBH5) expression and its impact on form-deprivation myopia (FDM) retina in guinea pigs.Methods:Thirty normal SPF grade 3-week-old tricolor guinea pigs were randomly divided into normal control group and experimental group, with 15 in each group.In the experimental group, the right eyes were covered as FDM group and the left eyes uncovered were set as self-control group.Ocular biometry was performed at one-week intervals from baseline to week 4 of the experiment.Spherical equivalent was detected by streak retinoscopy and axial length was measured by A-scan ultrasonography.Animals were sacrificed after 4 weeks of modeling.The distribution and expression of ALKBH5 protein in the guinea pig retina was detected by immunohistochemical and immunofluorescence staining.Expression of ALKBH5 mRNA and protein in guinea pig retina was detected by real-time fluorescence quantitative PCR and Western blot, respectively.The use of animals in ophthalmic and vision research followed the tenets of Animal Research in Vision and Ophthalmology, and the study was approved by the Ethics Committee of North Sichuan Medical College (No.2023087).Results:At weeks 2, 3, and 4 after myopia induction, diopters and axial lengths were significantly higher in the FDM group than in the normal control group and the self-control group (all at P<0.001). Immunohistochemistry and immunofluorescence assays showed that ALKBH5 protein was expressed in the retinal nerve fiber layer, rod/cone photoreceptor cells, and retinal pigment epithelium (RPE) layer, and was highly expressed in the retinal nerve fiber layer and RPE layer.The relative ALKBH5 immunofluorescence intensity in the normal control group, self-control group and FDM group was 1.000±0.204, 0.874±0.076 and 0.571±0.053, respectively, which was lower in the FDM group than in the normal control and self-control groups, showing statistically significant differences ( t=4.069, P=0.006; t=5.176, P=0.014). After 4 weeks of modeling, ALKBH5 mRNA and protein expressions were significantly lower in FDM group than in normal control and self-control groups (both at P<0.01). Conclusions:The expression of m6A demethylase ALKBH5 is decreased in the retina of FDM guinea pigs, suggesting that ALKBH5 and related m6A methylation modification may be involved in the development and progression of myopia.
ABSTRACT
Objective:To evaluate the difference and agreement of cycloplegic refraction between adaptive optics visual simulator (VAO) and conventional refraction methods.Methods:A diagnostic test study was conducted.Thirty-one eyes of 31 healthy subjects including 15 males and 16 females were enrolled in November, 2019 in Affiliated Hospital of North Sichuan Medical College.Mean age of the subjects was (20.1±1.0) years, and the right eye was taken for data analysis.Cycloplegic refraction was measured by VAO and conventional refraction methods, respectively.Spherical power, cylindrical power, Jackson cross-cylinder power at axis 90° and 180° (J 0) and Jackson cross-cylinder power at axis 45° and 135° (J 45) vector powers were recorded.Paired t-test was used to compare the refractive parameters between different refraction methods, and the intraclass correlation coefficient (ICC) and Bland-Altman plots were used to evaluate the agreement between VAO and conventional refraction methods.This study adhered to the Declaration of Helsinki, and the research protocal was approved by an Ethics Committee of Affiliated Hospital of North Sichuan Medical College (No.2020ER[A]018). Written informed consent was obtained from each subject prior to any medical examination. Results:For subjective refraction, the ICC for spherical power, cylindrical power, J 0 and J 45 between VAO and phoropter were 0.97, 0.75, 0.84 and 0.09, respectively.For objective refraction, the ICC for spherical power, cylindrical power, J 0 and J 45 between VAO and autorefractor were 0.98, 0.70, 0.74 and 0.61, respectively.The mean differences in spherical power, cylindrical power, J 0 and J 45 between VAO and phoropter were (0.05±0.32), (-0.23±0.28), (-0.10±0.14) and (-0.04±0.16)D, respectively, and the differences in cylindrical power and J 0 were statistically significant (both at P<0.01), whereas no significant differences in spherical power and J 45 were found ( P=0.41, 0.18). The mean differences in spherical power, cylindrical power, J 0 and J 45 measured by VAO and autorefractor were (-0.70±0.26), (-0.07±0.46), (-0.03±0.27) and (0.01±0.12)D, respectively, and the spherical power measurement by VAO was significantly more negative than the autorefractor ( t=15.09, P<0.01), while no significant differences in cylindrical power, J 0 and J 45 were found ( P=0.39, 0.59, 0.63). No significant difference values in spherical power, cylindrical power, J 0 and J 45 were found between the two objective refraction methods and phoropter subjective refraction (all at P>0.05). Conclusions:With cycloplegia, spherical power obtained by VAO objective refraction is more negative compared with autorefractor.There is a good agreement of spherical power and astigmatism vector values measured by VAO and phoropter subjective refraction, and the measurement differences are clinically acceptable.
ABSTRACT
Objective:To investigate the repeatability and correlation in tilt and decentration measurement of crystalline lens and intraocular lens (IOL) under non-mydriatic and mydriatic conditions using swept-source ocular coherence tomography CASIA2.Methods:A diagnostic test study was conducted.A total of 109 cataract patients (157 eyes) who received phacoemulsification with IOL implantation surgery in the Affiliated Hospital of North Sichuan Medical College from March to July 2020 were enrolled.The decentration and tilt of crystalline lens and IOL under non-mydriatic and mydriatic conditions were measured for three times by a single examiner using CASIA2 before and one week after surgery.The 0.5% compound tropicamide eye drops were used to dilate.Repeatability was evaluated by within-standard deviation, test-retest repeatability (TRT), coefficient of variation (CoV) and intraclass correlation coefficient (ICC). The correlation in decentration and tilt of crystalline lens and IOL between before and after mydriasis was assessed by Pearson correlation coefficient.This study adhered to the Declaration of Helsinki, and the study protocol was approved by an Ethics Committee of the Affiliated Hospital of North Sichuan Medical College (No.2020ER030-1). Written informed consent was obtained from all subjects before any medical examination.Results:The decentration of crystalline lens under non-mydriatic and mydriatic conditions was (0.217±0.112)mm and (0.220±0.110)mm, respectively, and the tilt was (5.017±1.422)° and (5.310±1.645)°, respectively.The decentration of IOL under non-mydriatic and mydriatic conditions was (0.245±0.136)mm and (0.250±0.145)mm, respectively, and the tilt was (5.144±1.345)° and (5.437±1.646)°, respectively.No significant difference was found between non-mydriatic and mydriatic conditions (all at P>0.05). Under both non-mydriatic and mydriatic conditions, the crystalline lenses of both eyes decentered and tilted toward the inferotemporal direction, and the IOL of right eyes decentered toward the inferior and tilted toward the inferotemporal direction, and the IOL of left eyes decentered and tilted toward the inferotemporal direction.Except the crystalline lens decentration, the measurement repeatability of crystalline lens tilt, IOL decentration and tilt in cataract patients before and after mydriasis was good, with ICC range in 0.815-0.984, TRT<50% and CoV≤14.840%.The measurement repeatability of crystalline lens decentration was poor, and the measurement repeatability of decentration axis, tilt and tilt axis of crystalline lens, and the repeatability of decentration and tilt of IOL were good in both eyes, with ICC range in 0.757-0.998, TRT<50% and CoV≤17.763%.There were good correlations in decentration, decentration axis, tilt and tilt axis of crystalline lens and IOL between non-mydriatic and mydriatic conditions (all r≥0.679, all at P<0.01). Conclusions:The measurement repeatability of decentration axis, tilt and tilt axis of crystalline lens and IOL, as well as the decentration of IOL by CASIA2 before and after mydriasis is good.The correlations of the measured parameters before and after mydriasis are good.