Factors associated with axial length elongation in high myopia in adults

AIM:To investigate the association of axial length(AL)and ocular factors on AL elongation.METHODS:A retrospective chart review of patients who underwent two or more AL examinations for more than two years.Totally 4 groups were divided according to initial AL(<24 mm,24-26 mm,26-28 mm,≥28 mm).Initial fundus photograph was used to find risk factors associated AL elongation.RESULTS:The mean age of the patients was 47.21±7.79 y.AL remained almost unchanged in the groups with AL<24 mm and 24≤AL<26 mm.On the contrary,AL increased by 0.011 mm/y in the group with 26≤AL<28 mm and 0.035 mm/y in the group with AL≥28 mm(P<0.001).In high myopia,AL elongation increased in eye with longer AL(r=0.003,P=0.024),female gender(r=0.014,P=0.019),eye with larger peripapillary chorioretinal atrophic area(r=0.002,P=0.019),and smaller vascular arcade angle(r=-0.004,P=0.006).The risk of elongation 0.03 mm/y in high myopia was increased in female gender(P=0.040),and gradually increased in eye with large peripapillary chorioretinal atrophy area(P<0.01).CONCLUSION:AL elongate significantly in the eye with longer AL,female gender,and the eye with larger atrophic area and smaller arcade angle on fundus photography.

Comparison of myopia control between toric and spherical periphery design orthokeratology in myopic children with moderate-to-high corneal astigmatism

AIM： To compare clinical results between toric and spherical periphery design orthokeratology（ortho-k） in myopic children with moderate-to-high corneal astigmatism. METHODS： This retrospective study enrolled 62 eyes of 62 subjects using toric ortho-k lenses. These subjects were assigned to the toric group. Based on the one-to-one match principle（same age, proximate spherical equivalence and corneal astigmatism）, 62 eyes of 62 subjects were enrolled and included in the spherical group. At one-year followup visit, visual acuity, corneal astigmatism, treatment zone decentration, axial elongation and adverse reaction were compared between these two groups. RESULTS： At the one-year visit, corneal astigmatism was significantly lower in the toric group（1.22±0.76 D） than in the spherical group（2.05±0.85 D）（P=0.012）. The mean magnitude of the treatment zone decentration was 0.62±0.42 mm in the toric group and 1.07±0.40 mm in the spherical group（P=0.004）. Axial elongation was significantly slower in the toric group（0.04±0.13 mm） than in the spherical group（0.09±0.13 mm）（P=0.001）. The oneyear axial elongation was significantly correlated with initial age（r=-0.487, P〈0.001） and periphery design of ortho-k lens（r=0.315, P〈0.001）. The incidence of corneal staining was lower in the toric group（8.1%） than in the spherical group（19.4%）（P〈0.001）. CONCLUSION： Toric periphery design ortho-k lenses may provide lower corneal astigmatism, better centration, slower axial elongation and lower incidence of corneal staining in myopic children with moderate-to-high corneal astigmatism.

Retinal structural-vascular-functional relationship using optical coherence tomography and optical coherence tomography -angiography in myopia

Background:To examine the retinal structure–vascular-function relationship using optical coherence tomography(OCT)and optical coherence tomography angiography(OCTA)in myopia.Methods:This was a prospective cross-sectional study comprising 86 eyes of 45 individuals with varying axial lengths and spherical equivalents and no posterior segment abnormalities.All eyes underwent optical coherence tomography with the Spectralis SD-OCT and OCTA with RTVue-XR Avanti;Optovue.Individual macular retinal layer thicknesses and flow areas and vessel densities were measured on OCT and OCTA,respectively.Linear correlations were made between the macular layer thicknesses,flow areas and vessel densities with axial length,spherical equivalent and visual acuity.Results:The participants’mean ages were 33.34±14.45 years,mean spherical equivalent refractions were−7.17±5.71 D and axial lengths were 25.95±2.41 mm.There were significant positive correlations of foveal angle(r=0.757,p=0.001),inner retinal(r=0.764,p=0.001)and outer plexiform layer(r=0.771,p=0.001)thickness on OCT and vessel densities in deep capillary plexus(r=0.313,p=0.003)on OCTA with axial length and negative correlations with spherical equivalents and visual acuity.Significant negative correlations of outer nuclear layer(r=−0.560,p=0.03)and photoreceptor outer segment layer thickness(r=−0.856,p<0.001)were noted on OCT with axial length and positive correlations with spherical equivalents and visual acuity.Conclusion:The lateral retinal stretching in myopia could possibly explain the correlation between retinal layer thickness,vascular density and visual acuity in these eyes.Further research is required to investigate this.