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The Effect of Altitude on Intraocular Pressure in Vitrectomized Eyes with Sulfur Hexafluoride Tamponade by the Friedenwald Method: Rabbit Animal Model

View Article: PubMed Central - PubMed

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 SF6 without 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 SF6 at 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.

No MeSH data available.


Related in: MedlinePlus

Scatter plot and regression lines from all cases in the rabbit model. m: meters. SF6: sulfur hexafluoride. BSS: balanced saline solution.
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fig2: Scatter plot and regression lines from all cases in the rabbit model. m: meters. SF6: sulfur hexafluoride. BSS: balanced saline solution.

Mentions: Figure 2 shows the scatter plot and best fit lines resulting from the regression for each case; the eyes with the steepest slopes (higher impact of altitude over IOP) were (from higher to lesser impact) 100% SF6, 100% air, 25% SF6, and 50% SF6, while the eye with SF6 and no vitrectomy and the eye with vitrectomy and BSS displayed a very low slope, thus proving that an altitude variation has no impact on the IOP on the control eye.


The Effect of Altitude on Intraocular Pressure in Vitrectomized Eyes with Sulfur Hexafluoride Tamponade by the Friedenwald Method: Rabbit Animal Model
Scatter plot and regression lines from all cases in the rabbit model. m: meters. SF6: sulfur hexafluoride. BSS: balanced saline solution.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5121576&req=5

fig2: Scatter plot and regression lines from all cases in the rabbit model. m: meters. SF6: sulfur hexafluoride. BSS: balanced saline solution.
Mentions: Figure 2 shows the scatter plot and best fit lines resulting from the regression for each case; the eyes with the steepest slopes (higher impact of altitude over IOP) were (from higher to lesser impact) 100% SF6, 100% air, 25% SF6, and 50% SF6, while the eye with SF6 and no vitrectomy and the eye with vitrectomy and BSS displayed a very low slope, thus proving that an altitude variation has no impact on the IOP on the control eye.

View Article: PubMed Central - PubMed

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 SF6 without 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 SF6 at 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.

No MeSH data available.


Related in: MedlinePlus