PDF(Pubmed)
Abstract：
BACKGROUND: Cataracts affect the optics of the eye in terms of absorption, blur, and scattering. When cataracts are unilateral, they cause differences between the eyes that can produce visual discomfort and harm binocular vision. These interocular differences can also induce differences in the processing speed of the eyes that may cause a spontaneous Pulfrich effect, a visual illusion provoking important depth misperceptions. Interocular differences in light level, like those present in unilateral cataracts, can cause the Classic Pulfrich effect, and interocular differences in blur, like those present in monovision, a common correction for presbyopia, can cause the Reverse Pulfrich effect. The visual system may be able to adapt, or not, to the new optical condition, depending on the degree of the cataract and the magnitude of the monovision correction.
METHODS: Here, we report a unique case of a 45-year-old patient that underwent unilateral cataract surgery resulting in a monovision correction of 2.5 diopters (D): left eye emmetropic after the surgery compensated with a monofocal intraocular lens and right eye myopic with a spherical equivalent of -2.50 D. This patient suffered severe symptoms in binocular vision, which can be explained by a spontaneous Pulfrich effect (a delay measured of 4.82 ms, that could be eliminated with a 0.19 optical density filter). After removing the monovision with clear lens extraction in the second eye, symptoms disappeared. We demonstrate that, at least in this patient, both Classic and Reverse Pulfrich effects coexist after unilateral cataract surgery and that can be readapted by reverting the interocular differences. Besides, we report that the adaptation/readaptation process to the Reverse Pulfrich effect happens in a timeframe of weeks, as opposed to the Classic Pulfrich effect, known to have timeframes of days. Additionally, we used the illusion measured in the laboratory to quantify the relevance of the spontaneous Pulfrich effect in different visual scenarios and tasks, using geometrical models and optic flow algorithms.
CONCLUSIONS: Measuring the different versions of the Pulfrich effect might help to understand the visual discomfort reported by many patients after cataract surgery or with monovision and could guide compensation or intervention strategies.
METHODS: Here, we report a unique case of a 45-year-old patient that underwent unilateral cataract surgery resulting in a monovision correction of 2.5 diopters (D): left eye emmetropic after the surgery compensated with a monofocal intraocular lens and right eye myopic with a spherical equivalent of -2.50 D. This patient suffered severe symptoms in binocular vision, which can be explained by a spontaneous Pulfrich effect (a delay measured of 4.82 ms, that could be eliminated with a 0.19 optical density filter). After removing the monovision with clear lens extraction in the second eye, symptoms disappeared. We demonstrate that, at least in this patient, both Classic and Reverse Pulfrich effects coexist after unilateral cataract surgery and that can be readapted by reverting the interocular differences. Besides, we report that the adaptation/readaptation process to the Reverse Pulfrich effect happens in a timeframe of weeks, as opposed to the Classic Pulfrich effect, known to have timeframes of days. Additionally, we used the illusion measured in the laboratory to quantify the relevance of the spontaneous Pulfrich effect in different visual scenarios and tasks, using geometrical models and optic flow algorithms.
CONCLUSIONS: Measuring the different versions of the Pulfrich effect might help to understand the visual discomfort reported by many patients after cataract surgery or with monovision and could guide compensation or intervention strategies.
摘要：
背景：白内障在吸收方面会影响眼睛的光学，blur,和散射。当白内障是单方面的，它们引起眼睛之间的差异，会产生视觉不适并损害双眼视觉。这些眼间差异也会引起眼睛处理速度的差异，从而可能引起自发的Pulfrich效应，引起重要深度误解的视觉错觉。光级的两眼间差异,像那些出现在单侧白内障中的人，会引起经典的Pulfrich效应,和模糊的眼间差异，就像monovision中的那些人一样，老花眼的常见矫正方法，会导致反向Pulfrich效应。视觉系统可能能够适应，或者不是，在新的光学条件下，取决于白内障的程度和单视矫正的程度。
方法：这里，我们报告了一例45岁患者的独特病例，该患者接受了单侧白内障手术，导致2.5屈光度（D）的单视矫正：手术后的左眼正视眼补偿了单焦点人工晶状体和右眼近视，球面等效为-2.50D。这可以用自发的Pulfrich效应(测量的延迟为4.82ms，这可以用0.19的光密度滤波器消除)。在第二只眼睛中取出清晰的晶状体摘除单视后，症状消失。我们证明，至少在这个病人身上,单侧白内障手术后，经典和反向Pulfrich效应并存，可以通过恢复眼间差异来重新适应。此外,我们报告说，适应/重新适应过程的反向Pulfrich效应发生在几周的时间范围内，与经典的Pulfrich效应相反,已知有几天的时间范围。此外,我们使用实验室测量的错觉来量化自发Pulfrich效应在不同视觉场景和任务中的相关性，使用几何模型和光流算法。
结论：测量Pulfrich效应的不同版本可能有助于了解白内障手术后或单视手术患者报告的视觉不适，并可以指导补偿或干预策略。
方法：这里，我们报告了一例45岁患者的独特病例，该患者接受了单侧白内障手术，导致2.5屈光度（D）的单视矫正：手术后的左眼正视眼补偿了单焦点人工晶状体和右眼近视，球面等效为-2.50D。这可以用自发的Pulfrich效应(测量的延迟为4.82ms，这可以用0.19的光密度滤波器消除)。在第二只眼睛中取出清晰的晶状体摘除单视后，症状消失。我们证明，至少在这个病人身上,单侧白内障手术后，经典和反向Pulfrich效应并存，可以通过恢复眼间差异来重新适应。此外,我们报告说，适应/重新适应过程的反向Pulfrich效应发生在几周的时间范围内，与经典的Pulfrich效应相反,已知有几天的时间范围。此外,我们使用实验室测量的错觉来量化自发Pulfrich效应在不同视觉场景和任务中的相关性，使用几何模型和光流算法。
结论：测量Pulfrich效应的不同版本可能有助于了解白内障手术后或单视手术患者报告的视觉不适，并可以指导补偿或干预策略。
