10.07.2015 Views

Visual Psychophysics / Physiological Optics - ARVO

Visual Psychophysics / Physiological Optics - ARVO

Visual Psychophysics / Physiological Optics - ARVO

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

<strong>ARVO</strong> 2013 Annual Meeting Abstracts by Scientific Section/Group – <strong>Visual</strong> <strong>Psychophysics</strong> / <strong>Physiological</strong> <strong>Optics</strong>regression analysis was conducted to determine the relation betweenbaseline refractive astigmatism and change per year in SE refractiveerror with age (change is SE/fu interval). The following variableswere also included: sex, baseline age, follow-up interval, baseline SE.Results: For the 2,043 subjects who met inclusion criteria, mean agewas 6.13 years (SD 2.90) at baseline and 10.70 years (SD 3.56) atfollow-up, with a mean follow-up interval of 4.57 years (SD 3.28).SE tended to shift towards less hyperopia/more myopia with age inmost children (Table 1). On average, there was a shift towards lesshyperopia/more myopia of 0.16 D/year (Table 2). Neither of thesetrends varied significantly with amount of baseline astigmatism.Regression analysis yielded significant effects of age, sex, length offollow-up interval, and baseline SE on change per year in SE, but nosignificant effect of baseline astigmatism magnitude.Conclusions: The results of the present study indicate that highlyastigmatic children in this population are not at increased risk fordevelopment or progression of myopia.Sensor, the Pediatric Wavefront Evaluator (PeWE). Children rangedin age from 6 mos to 9 yrs. Images were recorded while childrenwatched a cartoon at 50 cm (near, n) and 2 m (distant, d) viewingdistance. At least 7 focused and centered images were obtained atboth fixation distances, with undilated pupil diameters ranging from 3to 5 mm. Zernike decomposition to 4th order was performed. Lowerorder aberrations were converted to m, j0 and j45. Signed Zerniketerms Z(3,1) (y coma, yc), Z(3,-1) (x coma, xc) and Z(4, 0) (sphericalaberration, sa) were derived for the observed mm pupil diameter(mmpd). Three different pupil scaling methods were used: (1) allterms were scaled down to 3mmpd, (2) those greater than 4 mmpdscaled down to 4 mmpd (data with pupil < 4 mm excluded), and (3)all were scaled up to 5 mmpd. Within each subject, at least 3observations were required at 4mmpd to be averaged, while 7 werealways averaged at 5 mmpd and 3 mmpd. Paired sample (d and n) t-tests on the signed coefficients (micron) were compared at 3, 4, and 5mmpd.Results: As expected, accommodation produced a change in m fromn to d of -1.33 to -0.25D (p=0.000). A small (

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!