Photoreceptor cone loss is associated with decreased deep retinal vessel density and impaired retinal sensitivity in high myopia

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 p<0.01), except for foveal VDs in both capillary plexuses and parafoveal VD in DCP (all p>0.05). 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.