Swept Source Optical Coherence Tomography Findings in Gas-Filled Eyes after Macular Hole Surgery

PURPOSE: To investigate the ability to determine the postoperative status of macular hole (MH) in gas-filled eyes using swept source optical coherence tomography (SS-OCT). METHODS: Ten eyes of 10 patients who underwent vitrectomy, internal limiting membrane peeling and gas tamponade for idiopathic MH were included in this study. The macular area was examined using SS-OCT on postoperative days 1, 2 and 30. RESULTS: MH status was assessed in 6 eyes (60%) on postoperative day 1 and MH closure was confirmed in 5 of the 6 eyes (83%). MH remained closed in all 5 eyes at 1 month after surgery. Only gas-retinal interface was obtained in 4 eyes (40%) and unclosed MH was found in 1 of the 4 eyes (25%) at 1 month after surgery. CONCLUSIONS: The MH status can be determined using SS-OCT in the early postoperative period even in gas-filled eyes. Confirming early MH closure with SS-OCT can serve as an important guide to significantly shorten the duration of prone positioning while maintaining high closure rates.

Intraocular Pressure Assessment in Vitrectomized Gas-filled Eyes

We assessed the accuracy of Goldmann or Schi-(phi)tz tonometric readings in the gas filled vitrectomized eyes. We performed pars plana vitrectomy with or without lensectomy in 8 rabbit eyes, and in 6 enucleated porcine eyes. Fluid-air exchange was done at the end of the procedure. Intraocular pressure was measured using Goldmann tonometer and Schi-(phi)tz tonometer and was compared with true pressure which was monitored by manometer with indwelling catheter in the intravitreal cavity. Goldmann and Schi-(phi)tz tonometry always showed lower presure value than manometeric one(P0.05).

Measurement of Intraocular Pressure in Gas-filled Human Eye

The injection of various long-lasting inert gases into the vitreous cavity to flatten and support a detached retina is of proven value. Persistence of the inert gas can be advantageous from the point of view of retinal detachment surgery, but they can cause rising of the intraocular pressure(IOP) to a dangerously high level. So an accurate assessment of IOP in gas-filled eye is important. Previous studies documented that Schiotz tonometry significantly underestimates IOP in the gas-filled rabbit eye, and Goldmann tonometry is more accurate. But in the operating room, Schiotz tonometer is the only device to measure the IOP, so the relationship between the true lOP and the IOP measured by the Schiotz tonometry in the human eye is very important. In this study an attempt was made to find the extent of discrepancy between Schiotz and Goldmann tonometry in the assessment of IOP in the gas-filled human eye. We performed pars plana vitrectomy in 12 human eyes and pars plana vitrectomy with lensectomy in 10 human eyes. Postoperatively fluid-gas exchange was done with 15% perfluoropropane gas(C3F8). The IOP and gas level were checked immediately before fluid-gas exchange and 3hr, 6hr, 12hr, 24hr and 72hr after fluid-gas exchange using Schiotz and Goldmann tonometer. The relationship between IOP measured by Schiotz and Goldmann tonometer was suggested. In phakic and aphakic eyes, Schiotz tonometrry always gave a lower value, and the discrepancy seemed to be greater in the eyes filled with more gas.