Corneal HOAs showed predictive capabilities for both mean horizontal and vertical choroidal thickness in new research. Specifically, comatic and trefoil components of HOAs were identified as important predictors of choroidal parameters. This image from the study shows the choroidal vascularity index and choroidal thickness in the macular zone segmented by region. T1: temporal parafovea; T2: temporal perifovea; N1: nasal parafovea; N2: nasal perifovea; I1: inferior parafovea; I2: inferior perifovea; S1: superior parafovea; S2: superior perifovea; C: center. Photo: Ruan K, et al. BMC Ophthalmol. 2024;24:500. Click image to enlarge.

Growing evidence links higher-order aberrations (HOAs) to the development and progression of myopia. The authors of a recent study in BMC Ophthalmology noted, “Understanding the specific characteristics of HOAs is clinically significant, as it helps optimize wavefront-guided excimer laser refractive surgery, tailor custom IOL implants and design effective contact lenses that can potentially slow myopia progression.” In their investigation, the research team explored the relationship between choroidal parameters and HOAs; they chose to focus on this part of the eye since it’s known to regulate HOAs to improve retinal image quality, and changes in choroidal vasculature serve as early indicators of vision-related alterations in ocular growth and myopia development.

The study included 321 myopic participants aged 18 to 45 who underwent comprehensive eye examinations and were grouped based on their axial lengths (AL):

• Mild myopia: 105 eyes with a mean AL of 24.22mm and a spherical equivalent (SE) of 3.19D.
• Moderate myopia: 98 eyes with a mean AL of 25.51mm and an SE of 4.54D.
• High myopia: 118 eyes with a mean AL of 27.04mm and an SE of 7.30D.

Corneal HOAs were measured using a high-resolution rotating Scheimpflug camera, while choroidal parameters, including the choroidal vascularity index (CVI) and thickness, were assessed using swept-source OCT (SS-OCT). Various types of HOAs were compared, including spherical, comatic and trefoil aberrations.

The analyses showed that patients in the high myopia group exhibited a notably lower spherical HOA root mean square compared to those with low myopia. Additionally, CVI was found to decrease significantly with longer axial lengths.

The researchers observed that comatic and trefoil components of HOAs were important predictors of choroidal parameters: both could predict mean horizontal CVI, and the comatic component was correlated with both mean vertical and horizontal choroidal thickness.

“Our findings revealed that eyes with a longer AL had lower absolute values of spherical aberration and horizontal coma, as well as a decrease in choroidal vascularity and thickness,” the study authors summarized in their paper. They commented that the observed correlations between choroidal perfusion and thickness with horizontal coma, as well as the correlation between the trefoil and the mean CVI of the horizontal scan, “[imply] a potential link between optical quality and ocular perfusion in myopia,” which they note holds “significant potential for myopia management, especially in the development of personalized treatment approaches.”

The authors concluded by proposing that future research “investigate the longitudinal effects of HOA modulation on choroidal structure to better understand its potential role in personalized treatment plans for myopia management.”