Limits...
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

Estimated data for human eyes. Regression lines with 95% confidence interval lines for eyes with 100% SF6 and 50% SF6. m: meters. SF6: sulfur hexafluoride.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5121576&req=5

fig5: Estimated data for human eyes. Regression lines with 95% confidence interval lines for eyes with 100% SF6 and 50% SF6. m: meters. SF6: sulfur hexafluoride.

Mentions: Estimations for humans revealed that 100% SF6, 50% SF6, 25% SF6, and 100% air eyes showed similar behaviors (nonsignificant differences), while the eye with SF6 and no vitrectomy and the eye with vitrectomy and BSS showed no IOP changes in connection with altitude variations (as in rabbits). Figures 5 and 6 illustrate the differences in the estimates for humans between 50 and 100% SF6 fill against 100% SF6 with no vitrectomy and vitrectomy with BSS.


The Effect of Altitude on Intraocular Pressure in Vitrectomized Eyes with Sulfur Hexafluoride Tamponade by the Friedenwald Method: Rabbit Animal Model
Estimated data for human eyes. Regression lines with 95% confidence interval lines for eyes with 100% SF6 and 50% SF6. m: meters. SF6: sulfur hexafluoride.
© Copyright Policy
Related In: Results  -  Collection

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

fig5: Estimated data for human eyes. Regression lines with 95% confidence interval lines for eyes with 100% SF6 and 50% SF6. m: meters. SF6: sulfur hexafluoride.
Mentions: Estimations for humans revealed that 100% SF6, 50% SF6, 25% SF6, and 100% air eyes showed similar behaviors (nonsignificant differences), while the eye with SF6 and no vitrectomy and the eye with vitrectomy and BSS showed no IOP changes in connection with altitude variations (as in rabbits). Figures 5 and 6 illustrate the differences in the estimates for humans between 50 and 100% SF6 fill against 100% SF6 with no vitrectomy and vitrectomy with BSS.

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