Purpose: To assess alterations in cone morphology, retinal sublayer thicknesses and vessel densities (VDs) in eyes with non-pathological high myopia (HM) and their correlation with retinal sensitivity (RS). Methods: This prospective study included 43 patients with non-pathological HM and 38 age-matched healthy volunteers. Participants underwent detailed ophthalmic evaluations. Cone morphology was assessed using adaptive optics scanning laser ophthalmoscopy. The thicknesses of the myoid and ellipsoid zone (MEZ), photoreceptors outer segment (OS), central macula and choroid were measured by optical coherence tomography (OCT). Retinal VDs of the superficial and deep capillary plexus (DCP) were evaluated by OCT angiography, and RS was assessed through microperimetry. Group comparisons were conducted, and correlations among these parameters were explored. Results: The HM group showed significantly reduced cone density and regularity, increased cone dispersion and spacing at 3° eccentricity across four quadrants (all p<0.001) and decreased VDs (all p0.05). Additionally, MEZ, OS, central macula and choroid were thinner in HM (all p<0.001). Multivariate regression indicated that higher cone density correlated with shorter axial length (p= 0.013 ) and higher DCP whole VD (p=0.009). Better RS was related to higher cone density (p=0.026), thicker MEZ (p<0.001), thicker choroid (p=0.044) and higher DCP whole VD (p=0.009). Conclusions: Our findings demonstrate that impaired DCP perfusion independently predicts cone loss in non-pathological HM, independent of axial elongation. RS impairment is associated with cone loss, MEZ thinning and DCP hypoperfusion, indicating synergistic microvascular and structural damage in HM-related vision impairment.

Background/aims: The study aims to evaluate choroidal vascular changes in younger patients with myopia using ultrawidefield swept-source optical coherence tomography angiography (SS-OCTA). Methods: Overall, 724 eyes of 362 participants (177 males, 185 females, age: 32.43±6.20 years) underwent SS-OCTA imaging (24×20 mm). The eyes were divided into normal, low myopia (LM), moderate myopia (MM), high myopia and superhigh myopia groups according to the spherical equivalent refraction (SER). Changes in choroidal vascular thickness (ChVT) and density (ChVD) in nine grids of the fundus were analysed using the latest version of the built-in analysis software. Results: Axial length (AL) showed a negative correlation with SER (r=0.822, p=0.000); ChVT and ChVD showed a negative correlation with AL (p≤0.001) in all nine grids. In group analysis, compared with normal eyes, myopia affects ChVT earlier than ChVD, as observed in the LM and MM groups, respectively. The decrease in ChVT was most evident in the macular grid (β = −34.20, p=0.000), whereas the decrease in ChVD was most evident in the optic disc grid (β = −2.19, p=0.001). Conclusion: Myopia has a significant impact on choroidal vascular structure, resulting in spatiotemporal differences. Using SS-OCTA with a new version of the built-in analysis software and a study with a larger sample cohort may aid in providing more authentic information on choroidal vascular changes in eyes with myopia.

Background/aims To evaluate cone morphology, retinal sublayer thicknesses and vessel density (VD) and their associations with retinal sensitivity (RS) in red-green colour vision deficiency (CVD). Methods 36 patients with red-green CVD and 38 age-matched controls were enrolled. Diagnosis was confirmed by pseudoisochromatic plates and the Farnsworth-Munsell 100-hue test. All participants underwent adaptive optics scanning laser ophthalmoscopy (AO-SLO), optical coherence tomography (OCT), OCT-angiography and microperimetry. Results Patients with red-green CVD exhibited significantly decreased cone density and regularity, increased cone dispersion and spacing at 3° eccentricity, and thinner myoid and ellipsoid zone (MEZ) and outer segment (OS) (all p<0.01). VDs, blue-yellow error score and axial length did not differ between groups. Patients with CVD had higher red-green error scores and lower RS (p<0.05). Temporal cone density was correlated with RS only in CVD (r=0.410, p=0.011). Mean cone density correlated with favourable cone parameters and MEZ thickness (r=−0.827 to 0.862, p<0.005) and predicted higher RS (r=0.463, p<0.001). Conclusion Red-green CVD features reduced cone density, disorganised arrangement and MEZ and OS thinning, which are closely linked to RS. Cone structural integrity has clinical value for managing visual impairments in CVD.