Corneal shape changes after vitreoretinal surgery with fluid-gas exchange.

Area of Science:

• Ophthalmology
• Corneal Biomechanics
• Surgical Outcomes

Background:

• Vitrectomy is a common ophthalmic surgical procedure.
• Fluid-gas exchange is sometimes used during vitrectomy.
• Potential impacts of fluid-gas exchange on corneal shape are not fully understood.

Purpose of the Study:

• To investigate corneal shape changes following vitrectomy with and without fluid-gas exchange.
• To quantify the effect of fluid-gas exchange on corneal refractive power and astigmatism components.

Main Methods:

• Retrospective case-control study of 43 eyes undergoing vitrectomy and cataract surgery.
• Corneal shape measured using anterior segment optical coherence tomography (CASIA2) preoperatively and at multiple time points postoperatively.
• Fourier analysis applied to posterior corneal shape data to assess refractive power components.

Main Results:

• Eyes undergoing fluid-gas exchange showed significant increases in regular and asymmetry components of corneal power on postoperative day 1.
• Higher-order irregular astigmatism components also significantly increased in the gas group compared to the nongas group.
• The posterior cornea's shape, including spherical power and astigmatism, was significantly altered in the gas group post-surgery.

Conclusions:

• Fluid-gas exchange during vitrectomy leads to significant, measurable changes in corneal shape.
• These corneal shape alterations, particularly irregular astigmatism, are more pronounced and prolonged with fluid-gas exchange.
• Surgical invasion and fluid-gas exchange contribute to postoperative corneal shape modifications.