Persistent biases in subjective image focus following cataract surgery
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- 作者：Khatuna Parkosadze ; Teona Kalmakhelidze ; Marina Tolmacheva ; Georgi Chichua ; Archil Kezeli ; Michael A. Webster ; John S. Werner
- 关键词：Cataract ; Blur adaptation ; Spatial vision
- 刊名：Vision Research
- 出版年：2013
- 出版时间：30 August, 2013
- 年：2013
- 卷：89
- 期：Complete
- 页码：10-17
- 全文大小：1012 K
文摘
We explored the perception of image focus in patients with cataracts, and how this perception changed following cataract removal and implantation of an intraocular lens. Thirty-three patients with immature senile cataract and with normal retinal function were tested before surgery and 2 days after surgery, with 18 of the patients retested again at 2 months following surgery. The subjective focus of natural images was quantified in each session by varying the slope of the image amplitude spectra. At each time, short-term adaptation to the spectral slope was also determined by repeating the measurements after exposure to images with blurred or sharpened spectra. Despite pronounced acuity deficits, before surgery images appeared ¡°best-focused¡± when they were only slightly blurred, consistent with a strong compensation for the acuity losses. Post-operatively, the image slopes that were judged ¡°in focus¡± before surgery appeared too sharp. This bias remained strong at 2 months, and was independent of the rapid blur aftereffects induced by viewing filtered images. The focus settings tended to renormalize more rapidly in patients with higher post-operative acuity, while acuity differences were unrelated to the magnitude of the short-term blur aftereffects. Our results suggest that subjective judgments of image focus are largely compensated as cataracts develop, but potentially through a very long-term form of adaptation that results in persistent biases after the cataract is removed.