Attenuation of ocular wall pulsation in eyes containing a gas bubble after vitrectomy.

PURPOSE To evaluate the effect of an intraocular gas bubble on ocular wall pulsation. METHODS Eight patients that underwent vitrectomy with intraocular gas injection for various reasons were studied. Ocular pulsation was evaluated in a semi-quantitative way by means of Goldman applanation tonometry in both eyes before and after the operation. Vitreous cavity gas fill in the operated eye was estimated by means of indirect ophthalmoscopy and was correlated with ocular pulsation. The follow up lasted until the gas totally disappeared. RESULTS Ocular pulsation disappeared postoperatively in the operated eye and gradually reappeared when the gas fill diminished. Pulsation returned to preoperative level when the gas disappeared from the vitreous cavity. A negative statistical correlation between ocular pulsation and gas fill could be documented. CONCLUSION The compressible nature of the intraocular gas bubble results in absorption of the vascular pulsation and prevents its transfer to the ocular wall. This leads to attenuation or even cancellation of ocular wall pulsation when a gas bubble exists within the eye.