Ocular surface in patients with different degrees of myopia

AIM:To investigate the clinical features of the ocular surface in patients with different degrees of myopia.METHODS:A cross-sectional study was conducted involving 122 participants with myopia in Beijing Tongren Hospital from February to June,2023.After completing the Ocular Surface Disease Index(OSDI)score scale,measurements were taken for refraction,biometric parameters and ocular surface parameters.The prevalence,severity and related parameters of the dry eye among different groups based on axial length(AL)were compared.Correlation analysis was performed between ocular surface parameters and refraction/biometric measurement parameters.RESULTS:Statistically significant differences were observed in refractive error,corneal thickness,anterior chamber depth,and subfoveal choroidal thickness among the groups(all P<0.05).With the increase in AL,the incidence and severity of dry eye increased significantly(P<0.05).Moreover,the tear film break-up time(BUT)shortened(P<0.05),and the corneal fluorescein staining(CFS)points increased significantly(P<0.05).OSDI scores were positively correlated with AL and spherical equivalent(SE;both P<0.05);BUT was negatively correlated with AL,SE,and corneal astigmatism(AST;all P<0.05);Schirmer I test(SIT)results were negatively correlated with AL and SE(both P<0.05).CONCLUSION:AL elongation is a risk factor for dry eye onset in myopic participants.The longer the AL,the more severe the dry eye is,with the increased CFS spots and tear film instability.Additionally,SE and AST exhibit negative correlations with dry eye symptom scores and ocular surface parameters.

Reproducibility of optical quality parameters measured at objective and subjective best focuses in a doublepass system

AIMTo evaluate intra-session repeatability and reproducibility of optical quality parameters measured at objective and subjective best focuses in a double-pass system.METHODSThirty Chinese healthy adults (19 to 40 years old) meeting our inclusion criterion were enrolled in the study. After a basic eye examination, two methods of optical quality measurement, based on subjective and objective best focuses were performed using the Optical Quality Analysis System (OQAS) with an artificial pupil diameter of 4.0 mm.RESULTSWith each method, three consecutive measurements of the following parameters: the modulation transfer function cutoff frequency (MTFcutoff), the Strehl2D ratio, the OQAS values (OVs) at contrasts of 100%, 20%, 9% and the objective scatter index (OSI) were performed by an experienced examiner. The repeatability of each method was evaluated by the repeatability limit (RL) and the coefficient of repeatability (COR). Reproducibility of the two methods was evaluated by intra-class correlation coefficient (ICC) and the 95% limits of agreement (Bland and Altman analysis). Thirty subjects, seven females and twenty three males, of whom 15 right eyes and 15 left eyes were selected randomly for recruitment in the study. The RLs (percentage) for the six parameters measured at objective focus and subjective focus ranged from 8.44% to 15.13% and 10.85% to 16.26%, respectively. The CORs for the two measurement methods ranged from 8.27% to 14.83% and 10.63% to 15.93%, respectively. With regard to reproducibility, the ICCs for the six parameters of OQAS ranged from 0.024 to 0.276. The 95% limits of agreement obtained for the six parameters (in comparison of the two methods) ranged from -0.57 to 42.18 (MTFcutoff), -0.01 to 0.23 (Strehl2D ratio), -0.02 to 1.40 (OV100%), -0.10 to 1.75 (OV20%), -0.14 to 1.80 (OV9%) and -1.46 to 0.18 (OSI).CONCLUSIONMeasurements provided by OQAS with either method showed a good repeatability. However, the results obtained from the two different measurement methods showed a poor reproducibility. These findings suggest that it might be best to evaluate patients' optical quality by OQAS using the best focus as chosen automatically by the instrument.

Neurotrophin signaling and visceral hypersensitivity

Neurotrophin family are traditionally recognized for their nerve growth promoting function and are recently identified as crucial factors in regulating neuronal activity in the central and peripheral nervous systems. The family members including nerve growth factor （NGF）, brain-derived neurotrophic factor （BDNF）, and neurotrophin-3 （NT-3） are reported to have distinct roles in the development and maintenance of sensory phenotypes in normal states and in the modulation of sensory activity in disease. This paper highlights receptor tyrosine kinase （Trk） -mediated signal transduction by which neurotrophins regulate neuronal activity in the visceral sensory reflex pathways with emphasis on the distinct roles of NGF and BDNF signaling in physiologic and pathophysiological processes. Viscero-visceral cross-organ sensitization exists widely in human diseases. The role of neurotrophins in mediating neural cross talk and interaction in primary afferent neurons in the dorsal root ganglia （DRG） and neurotrophin signal transduction in the context of cross-organ sensitization are also discussed.

Analysis of related factors of optical quality in healthy Chinese adults:a community-based population study

Background:In recent years,visual quality has been extensively investigated in various conditions.In this community-based population study,we analyzed the effects of aging,refraction,and Lens Opacification Classification System III(LOCSIII)score on retinal imaging quality in healthy Chinese adults.Methods:This cross-sectional study was conducted on sub-group subjects from The Handan Eye Study between October 2012 and January 2013.Healthy subjects over 30-years-old with logarithm of the minimal angle of resolution(logMAR)best-corrected visual acuity(BCVA)less than 0 were included.Retinal image quality was measured by optical quality analysis system(OQAS)and recorded as modulation transfer function cutoff frequency(MTFcutoff),OQAS value(OV)100%,OV20%,OV9%,Strehl ratio(SR),and objective scatter index(OSI).The correlation between age,spherical equivalent refraction(SE),LOCSIII score,and optical quality parameters were investigated by multivariate analysis.Results:Among 1108 verified subjects,690 subjects(1380 eyes)met the inclusion criteria.Their age ranged from 30 to 76 years,SE ranged from-4.75 to 2.75 D.They were divided into five age groups(30–39,40–49,50–59,60–69,and≥70 years)for further analysis.After multivariate analysis by mixed-effect linear model,SR(t=-3.03,P=0.002),OV20%(t=-2.39,P=0.017),and OV9%(t=-3.16,P=0.001)significantly decreased with the increasing age,whereas logMAR BCVA(t=4.42,P<0.001)and OSI(t=4.46,P<0.001)significantly increased with age.As SE increased,SR(t=2.74,P=0.01),OV20%(t=2.31,P=0.02),and OV9%(t=2.79,P=0.005)significantly elevated,and OSI(t=-3.38,P<0.001)significantly decreased.With the increase in cortical opacity score,all optical quality parameters except for SR significantly decreased,including MTFcutoff(t=-2.78,P=0.01),OV100%(t=-2.78,P=0.005),OV20%(t=-2.60,P=0.009),and OV9%(t=-2.05,P=0.04).As posterior sub capsular opacity score increased,MTFcutoff(t=-2.40,P=0.02)and OV100%(t=-2.40,P=0.01)significantly decreased,while OSI(t=7.56,P<0.001)significantly increased.Conclusions:In healthy Chinese adult population,optical quality-related parameters significantly decrease with the increasing age,and OSI significantly increases with age.In normal BCVA subjects,optical quality is significantly impacted by cortical and posterior sub capsular opacity rather than by nuclear opacity.