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Peripheral image quality

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P148: Peripheral image quality in three types of myopia control  spectacles

Börjeson C1 , Papadogiannis P1 , Christaras D2 , Lundström L1
1-KTH Royal Institute Of Technology,
2-Diestia Systems

Due to the increasing prevalence of myopia in the world, myopia control spectacles have been  introduced in recent years. These spectacles typically have a central clear zone that corrects the  foveal refractive error, and an off-axis treatment zone. The aim of this study was to investigate how  these new spectacles affect peripheral image quality.
Three healthy adult subjects (one emmetrope, two myopes) were fitted with three pairs of myopia  control spectacles: MiyoSmart from Hoya, with Defocus Incorporated Multiple Segments (D.I.M.S.);  Stellest from Essilor, with Highly Aspherical Lenslet Targets (H.A.L.T.); and Perifocal from ArtOptica,  with horizontal progressive addition. The control case was single vision spectacles for the myopes  and no spectacles for the emmetrope. Central corrections were the same for the test spectacles and  the control case. Foveal and peripheral (30° nasal visual field) wavefront errors and through-focus  double-pass point spread functions (PSF) were measured for the right eye for all subjects with the  different spectacles. Each measurement was repeated three times. The fixation target was a backilluminated Maltese cross (2° visual angle), situated 3.25 m away from the eye. The same fixation  target was used for both the wavefront and the PSF measurements.
No consistent shift in relative peripheral refraction (RPR) was seen for Stellest and MiyoSmart.  However, there was a broadening in the peripheral double-pass PSFs for all subjects, causing an  overall reduction in the modulation transfer function (MTF) as calculated from the double-pass PSF.  At the same time, broadening was not observed when reconstructing the PSFs and MTFs from the  wavefront measurements. On the other hand, there was a significant myopic shift in RPR for Perifocal (linear mixed effects  model, p < 0.01), but their effect on the peripheral PSF and MTF was not consistent across subjects.  This to be expected, as each subjects’ baseline RPR affects if the add power results in better or worse  image quality.
Stellest and MiyoSmart induced a general broadening of the peripheral double-pass PSF without a  clear shift in refraction, whereas Perifocal induced a myopic shift that for some subjects also resulted  in a broadened PSF. This broadening in turn leads to a reduction in retinal contrast, which might  affect the progression of myopia
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