Comparative evaluation of the results of vitreoretinal surgery for idiopathic epiretinal membranes of stages 3 and 4 by Govetto with and without gas tamponade

Background. Vitreoretinal surgery for idiopathic epiretinal membranes (ERMs) is the most common surgical intervention performed on the posterior segment of the eye. Removal of the ERM leads to retinal relaxation and contributes to the restoration of its anatomical profile. However, in advanced stages of the process, when prolonged traction from the ERM causes displacement of retinal layers and significant stretching, the restoration of normal structure with a regular foveal contour is extremely slow and, in some cases, does not occur at all. In such situations, additional pressure on the retina by means of gas-air mixture tamponade may have a beneficial effect on the recovery of retinal morphology and improvement of visual function. Purpose: to perform a comparative assessment of the outcomes of vitreoretinal surgery for idiopathic ERMs of stage 3 and 4 by Govetto, with and without gas tamponade. Materials and methods. A total of 58 patients (66 eyes) with idiopathic ERMs were examined. Group 1 (stage 3 by Govetto) included 36 eyes: in 20 eyes, surgery was performed with tamponade using a 15% perfluoropropane gas-air mixture, and in 16 eyes, without vitreous cavity tamponade. Group 2 (stage 4 by Govetto) included 30 eyes: 17 eyes with tamponade using a 20% perfluoropropane gas-air mixture, and 13 eyes without tamponade. A standard vitreoretinal procedure was performed with removal of the posterior hyaloid membrane and ERM without peeling of the internal limiting membrane (ILM). In cases of ILM damage (6 eyes in group 1 and 11 eyes in group 2), the ILM was peeled up to the midpoint between the fovea and the optic disc margin. Results. The study demonstrated that parameters such as minimal foveal thickness, central retinal thickness, total measured retinal thickness, and retinal volume decreased significantly as early as 2 months after surgery in both stage 3 and stage 4 cases when gas tamponade was applied. In eyes operated without tamponade, a decrease in these parameters at the same follow-up period was not statistically significant. Gas tamponade also led to a statistically significant increase in the number of eyes with a normal ellipsoid zone at 6 months and 1 year of follow-up in both stages of the disease. In the group without vitreous cavity tamponade, an increase in the number of eyes with a normal ellipsoid zone remained statistically insignificant even at 1 year. Application of gas tamponade resulted in significant improvement of best-corrected visual acuity as early as 2 months, with further improvement during the 1-year follow-up. Recovery of best-corrected visual acuity in eyes without tamponade was significantly slower compared to those with tamponade. Conclusions. The study confirmed the high efficacy of applying a 15% perfluoropropane gas-air mixture in eyes with stage 3 ERM by Govetto and a 20% mixture in eyes with stage 4 ERM by Govetto in achieving faster restoration of retinal morphology, recovery of ellipsoid zone and visual acuity compared to surgery without vitreous cavity tamponade.