Background  

Dysmetropsia or distorted image size perception (smaller: micropsia; larger: macropsia) is known to occur after successful surgical re-attachment for macula-off rhegmatogenous retinal detachment. However, the vertical and horizontal components of size distortion have not been previously quantified separately. The purpose of this article is to describe horizontal and vertical dysmetropsia occurring in patients following pars plana vitrectomy and gas treatment (octafluoropropane, C₃F₈ or sulfur hexafluoride, SF₆) for macula-off rhegmatogenous retinal detachment.

Material and methods  

Four patients (mean±SD, 59±8 years; three women and one man) who had had pars plana vitrectomy and gas treatment for macula-off rhegmatogenous retinal detachment 6–7 months earlier underwent ocular examination, best corrected visual acuity test, threshold horizontal and vertical dysmetropsia measurement using a computerised version of the New Aniseikonia Test, slit-lamp examination and optical coherence tomography of the macula.

Results  

All patients had binocular visual complaints including difficulty judging distances or reading, rivalry or asthenopia. The logMAR visual acuity (mean±SD) in the operated eye was 0.52±0.199 and 0.02±0.171 in the unaffected eye. All patients perceived the image as smaller (micropsia) with the affected eye, with differences ranging from −9 to 0%. Four patients showed 3% or more size difference between horizontal and vertical meridians.

Conclusions  

Dysmetropsia does occur in symptomatic patients following successful surgical repair of macula-off rhegmatogenous retinal detachment by pars plana vitrectomy and gas treatment. The effect on image size is heterogenous across the retinal area affected.