title: The Effect of Altitude on Intraocular Pressure in Vitrectomized Eyes with Sulfur Hexafluoride Tamponade by the Friedenwald Method: Rabbit Animal Model.
abstract: The aim of this study is to assess the change in intraocular pressure after a road trip, in eyes with different levels of filling with gas tamponade. Five rabbit eyes were subject to pars plana vitrectomy and gas tamponade (filling percentage: 25%, 50%, and 100% of nonexpansile SF6, 100% saline solution, and 100% room air). A sixth eye was injected with 0.35 cc of undiluted SF6without vitrectomy. Guided by global positioning system, they were driven to the highest point of the highway connecting Mexico City with Puebla city and back, stopping every 300 m to assess intraocular pressure. The rabbit's scleral rigidity and estimation for human eyes were done by using the Friedenwald nomogram. Maximum altitude was 3209 m (Δ949 m). There were significant differences in intraocular pressure on the rabbit eyes filled with SF6at 100%, 50%, 25%, and 100% room air. Per every 100 m of altitude rise, the intraocular pressure increased by 1.53, 1.0046, 0.971, and 0.97 mmHg, respectively. Using the human Friedenwald rigidity coefficient, the human eye estimate for intraocular pressure change was 2.1, 1.8, 1.4, and 1.1 mmHg per every 100 m of attitude rise. Altitude changes have a significant impact on intraocular pressure. The final effect depends on the percentage of vitreous cavity fill and scleral rigidity.
authors.affiliation: Retina Department, Asociación para Evitar le Ceguera en México IAP, 04030 México City, Mexico.
authors.forename: Jans
authors.initials: J
authors.lastname: Fromow-Guerra
authors.affiliation: Retina Department, Asociación para Evitar le Ceguera en México IAP, 04030 México City, Mexico.
authors.forename: Adriana
authors.initials: A
authors.lastname: Solís-Vivanco
authors.affiliation: Retina Department, Asociación para Evitar le Ceguera en México IAP, 04030 México City, Mexico.
authors.forename: Raul
authors.identifier: 0000-0002-6457-4578
authors.initials: R
authors.lastname: Velez-Montoya
authors.affiliation: Retina Department, Asociación para Evitar le Ceguera en México IAP, 04030 México City, Mexico.
authors.forename: Adriana
authors.initials: A
authors.lastname: Perez-Reguera
authors.affiliation: Retina Department, Asociación para Evitar le Ceguera en México IAP, 04030 México City, Mexico.
authors.forename: Hugo
authors.initials: H
authors.lastname: Quiroz-Mercado
authors.affiliation: Retina Department, Asociación para Evitar le Ceguera en México IAP, 04030 México City, Mexico.
authors.forename: Armando
authors.initials: A
authors.lastname: Meza-de Regil
authors.affiliation: Retina Department, Asociación para Evitar le Ceguera en México IAP, 04030 México City, Mexico.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Papa-Oliva
authors.affiliation: Retina Department, Asociación para Evitar le Ceguera en México IAP, 04030 México City, Mexico.
authors.forename: Virgilio
authors.initials: V
authors.lastname: Morales-Cantón
mesh_terms: D000531:Altitude; D000818:Animals; D005123:Eye / Q000187:drug effects* / Q000503:physiopathology*; D040362:Geographic Information Systems; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects / Q000502:physiology*; D008137:Longitudinal Studies; D023421:Models, Animal; D011446:Prospective Studies; D011817:Rabbits; D013459:Sulfur Hexafluoride / Q000008:administration & dosage*; D014821:Vitrectomy / Q000379:methods
chemical_list: D013459:Sulfur Hexafluoride