title: Refractive shifts in four selected artificial vitreous substitutes based on Gullstrand-Emsley and Liou-Brennan schematic eyes.
abstract: OBJECTIVE
  To determine and compare the refractive shifts based on Gullstrand-Emsley and Liou-Brennan schematic eyes after filling them with four selected artificial vitreous substitutes: silicone oil, heavy silicone oil, hydrogels, and encapsuled balanced salt solution.
  
  
  METHODS
  The optical constants of artificial vitreous body-filled eyes were calculated based on Gullstrand-Emsley and Liou-Brennan schematic eyes with accommodation relaxed. The theoretical refractive shifts in these two models were compared in pars plana vitrectomy (PPV), PPV plus lensectomized and PPV plus intraocular lens (IOL) eyes after four artificial vitreous tamponades.
  
  
  RESULTS
  The Gullstrand-Emsley schematic eye shows refractive shifts of +8.710, -4.544, +1.136, and -0.338 D in PPV eyes; +11.044, +20.332, +16.351, and +17.413 D in PPV plus lensectomized eyes; and the need for IOL powers of +22.195, +22.366, +22.292, and +22.312 D in PPV plus IOL eyes in silicone oil, heavy silicone oil, hydrogels, and encapsuled balanced salt solution tamponade eyes, respectively. Similarly, the Liou-Brennan schematic eye induced shifts of +6.260, -3.266, +0.817, and -0.272 D in PPV eyes; +13.181, +20.654, +17.451, and +18.305 D in PPV plus lensectomized eyes; and the need IOL powers of +13.522, +23.767, +19.389, and +20.558 D in PPV plus IOL eyes, respectively.
  
  
  CONCLUSIONS
  The Gullstrand-Emsley schematic eye is a convenient and accurate model for predicting refractive shifts for hydrogels and encapsuled balanced salt solution substitutes in PPV eyes. The Liou-Brennan schematic eye is recommended for silicone oil and heavy silicone oil in PPV eyes and for all four substitutes in PPV plus lensectomized eyes and PPV plus IOL eyes. In addition, the encapsuled balanced salt solution changes the refraction little in either schematic eye.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Qianying
authors.initials: Q
authors.lastname: Gao
authors.forename: Xiang
authors.initials: X
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Ge
authors.forename: Yongji
authors.initials: Y
authors.lastname: Liu
authors.forename: Zhaoxin
authors.initials: Z
authors.lastname: Jiang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Lin
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000085:Acetates; D004338:Drug Combinations; D005137:Eye, Artificial; D006801:Humans; D020100:Hydrogels; D019654:Lens Implantation, Intraocular; D008903:Minerals; D008954:Models, Biological; D019591:Pseudophakia / Q000503:physiopathology; D012029:Refraction, Ocular / Q000502:physiology; D012030:Refractive Errors / Q000503:physiopathology*; D012827:Silicone Oils; D012965:Sodium Chloride; D014821:Vitrectomy; D014822:Vitreous Body
chemical_list: D000085:Acetates; C030660:BSS solution; D004338:Drug Combinations; D020100:Hydrogels; D008903:Minerals; D012827:Silicone Oils; C515608:densiron; D012965:Sodium Chloride