Choroidal thickness at age 66 years in the Danish high myopia study cohort 1948 compared with follow-up data on visual acuity over 40 years: a clinical update adding spectral domain optical coherence tomography

BACKGROUND AND PURPOSE: A population-based Copenhagen birth year 1948 cohort with high myopia recorded since age 14 years (spherical equivalent less than or equivalent to -6 D) has been followed over 50 years. Despite complications, current follow-ups have outlined a better visual prognosis than usually drawn from selected clinical series in the literature. For the present status at age 66 years, focus was on visual ability and choroidal thickness. METHODS: Twenty-eight of the original 39 participants were available in 2014. Medical history was updated. Best-corrected visual acuity (BCVA) data were compared with subfoveal choroidal thickness (SFCT), now measured by enhanced depth optical coherence tomography. RESULTS: Due to at least better eye visual acuity (VA), all patients had maintained their everyday visual capacity. Only one participant was marginal regarding visual status for a driver's licence; low vision was not on record. Based on all eyes, choroidal thickness correlated negatively with axial length (AL), which also held for the fraction with high myopia (AL >26.5 mm). In high myopia, the mean choroidal subfoveal thickness was 114 ± 75 μm versus 182 ± 94 μm in lower myopia (p = 0.01). CONCLUSION: Despite the generally maintained individual visual capacity in the series, significant correlation could be demonstrated between SFCT and (i) axial elongation and (ii) recorded VA, with a negative and a positive sign, respectively. Overall, the visual prognosis was relatively benign, in particular when compared with the selected high myopia hospital series that predominate in the ophthalmic literature.