Despite the high success rate of IMH surgeries, non-closure of MHs remains one of the most common complications following primary PPV [5]. The underlying causes of non-closure in IMHs after primary PPV are poorly understood but might be influenced by factors such as the course of the IMH, MH size, the type of tamponade agent, ILMP, and the extent of peeling. In this study, eight patients underwent phacoemulsification cataract extraction, intraocular lens implantation, 25-gauge vitrectomy, ILMP, and air tamponade as their primary surgeries. An examination on the first postoperative day revealed that only approximately 30–50% of air in the vitreous cavity remained (data not shown). This suggests that air leakage from the incision or inadequate posturing might have reduced the effective tamponade time, which appears to be a primary factor contributing to the non-closure of MHs after the initial operation.

For patients in whom primary surgical interventions fail, there is no consensus regarding the optimal retreatment strategy. Various assistive techniques, including expanding the range of ILMP, using ILM tamponade, performing ILM flap reversal, conducting MH edge massage, making radial incisions in the nerve fibre layer, administering autologous platelets, and using silicone oil tamponade, have been used to treat IMH after primary surgical failure [6]. While these adjunctive methods have improved the surgical success rate, they often necessitate a repeat PPV, leading to additional complexity and increased trauma for the patient.

Hillenkamp et al. [7] used OCT to evaluate the efficacy of reoperation for IMHs after primary PPV failure. They reported that MHs exhibiting a turned-up edge and ‘cuff’ of subretinal fluid were more likely to close during the second operation compared to those without these characteristics. Rishi et al. [8] performed a reoperation involving fluid-air exchange with 14% C3F8 gas injection, without expanding the range of ILMP, in a patient who had previously undergone PPV. Complete closure of the MH was observed at the 2-week follow-up after the reoperation. Additionally, Singh et al. [9] reported successful outcomes in three patients with IMHs who had failed primary PPV, using a simple fluid-air exchange followed by 14% C3F8 gas injection. These patients also demonstrated closure of the MHs and improvement in visual acuity 6 weeks post-surgery. Notably, the last two clinical case reports indicated that the patients presented with a ‘cuff’ of subretinal fluid before surgery, leading to anatomical closure of the MHs after gas injection. Hillenkamp and Rishi [7, 8] hypothesised that the pathogenesis of MHs closure primarily involves the centripetal movement of retinal tissue. In MHs characterised by the ‘cuff’ sign, there is a lack of adhesion to the retinal pigment epithelium at the edges and beneath the MHs. After gas injection, the retinal tissue moves toward the centre, promoting closure. Conversely, in MHs without the ‘cuff’ sign, closer adhesion to the retinal pigment epithelium might hinder closure, thus reducing the possibility of closure.

Another crucial factor for achieving MHs closure is maintaining a dry environment at the macular interface. This can be achieved by filling the vitreous cavity with gas or air, which prevents fluid from flowing into the subretinal space and restricts the entry of cellular components and growth factors that could hinder healing [10, 11]. Previous studies have indicated that most MHs close by the third postoperative day [12]. C3F8 has a longer tamponade duration than air owing to its expandable properties, which provide sustained support for maintaining a dry environment at the macular interface. A volume of 0.3 mL of C3F8 is sufficient to cover the MHs, thereby optimising the chances of successful closure.

A previous study indicated that patients with unclosed MHs after primary PPV but exhibiting a smaller or no change in size had a closure rate of up to 80% after reoperation [12]. All patients in that study presented with unclosed MHs after primary PPV, yet the holes were smaller than their preoperative dimensions. OCT analysis of these patients revealed wrapped hole edges accompanied by the characteristic ‘cuff’ sign. Drawing inspiration from these findings, we administered a simple intravitreal injection of 0.3 mL of C3F8 while ensuring a strict prone position postoperatively. Remarkably, all patients achieved MHs closure, and visual acuity improved to varying degrees. However, this study has several limitations: (1) the sample size was relatively small and (2) there was a lack of comparative data. Therefore, a prospective study with a larger sample size is required to validate these findings.

In conclusion, for patients with IMHs who experience failure following the first PPV operation, an intravitreal injection of 0.3 mL of C3F8 alone presents a straightforward, practical, and effective retreatment option, particularly when OCT examination reveals a ‘cuff’ sign.