Yabo Yang

Publications (2)5.18 Total impact

• Article: Retinal measurements using time domain OCT imaging before and after myopic Lasik.

  Feng Lei, Stephen A Burns, Liqin Shao, Yabo Yang
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  ABSTRACT: To compare retinal measurements obtained by time domain optical coherence tomography (OCT) devices before and after myopic laser in situ keratomileusis (Lasik) and to assess the interaction of Lasik and retinal structures as measured by time domain OCT. Fifty-three patients randomly selected participated in the study. Only the right eye of each subject was included in the study. Comprehensive ophthalmic examinations including refraction examination, slit lamp examination, dilated fundus examination, corneal topography, corneal thickness, intraocular pressure, and retinal Stratus OCT scans were acquired for each patient before myopic Lasik and 3months after surgery. Total macular volume (TMV) changed significantly between preoperative and postoperative measurements (p=0.003). No statistical differences were found between preoperative and postoperative disc area, rim area, cup/disk vert. ratio, or average foveal thickness (p>0.05). The variation in TMV correlated significantly with the change in spherical refraction equivalent, maximal corneal curvature, minimal corneal curvature, and corneal ablation depth. Most retinal OCT measurements undergo no obvious changes after myopic Lasik. The increased TMV measurements we measured after Lasik seem to be correlated with the alteration in corneal shape. The exact mechanism for this change is not clear, while we examined several possibilities including subclinical macular oedema, magnification changes, errors in OCT analysis and IOP, none of these seem to be a likely cause.
  Ophthalmic and Physiological Optics 05/2012; 32(3):222-7. · 1.58 Impact Factor
• Article: Pupil location under mesopic, photopic, and pharmacologically dilated conditions.

  Yabo Yang, Keith Thompson, Stephen A Burns
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  ABSTRACT: To determine whether there are systematic changes in pupil location with changes in the state of pupil size and with other ocular variables. High-resolution images of the pupil of the eyes of 70 subjects were taken using an infrared-sensitive camera. Images were obtained under mesopic, photopic, and pharmacologically dilated conditions. From the images, the center and diameter of the corneal limbus and the pupil were computed. In addition, the location of the first Purkinje image was calculated. The pupil center shifted consistently temporally as the pupil dilated. The total motion was relatively small, with a mean distance of 0.133 mm motion between the mesopic and photopic conditions, with the pupil diameter changing from 6.3 to 4.1 mm. Ninety percent of the subjects had a motion of less than 0.3 mm. One patient showed a motion of almost 0.6 mm. The change in location of the pupil center was not significantly related to refractive error, age, or the change of pupil diameter. Changes in the location of the pupil center with changes in the dilation of the pupil are typically slight, but can be significant in a few subjects, especially in pharmacologically dilated pupils.
  Investigative Ophthalmology &amp Visual Science 08/2002; 43(7):2508-12. · 3.60 Impact Factor