Comments on “Adequate Silicone Oil Tamponade by Utilizing the Space of Anterior Segment for Complicated Retinal Detachment: Technique, Efficacy, and Safety”

To the Editor:

We thank the authors for sharing their adequate silicone oil tamponade (ASOT) in dealing with complicated retinal detachment.¹ However, considering the clinical application and promotion of ASOT, we propose the following problems worthy of discussion.

• If the standard eye has a vitreous cavity (VC) volume of 4.5 mL, a lens volume of 200 µL, and an anterior chamber (AC) volume of 260 µL, ASOT only increases the amount of silicone oil (SO) in the AC. Considering that the average volume of 5.8 mL of SO was used, ASOT only increased the amount of SO by around 4.5% (0.26/5.8). Therefore, it is reasonable to question the clinical effect of a SO increase of <5%.
• It is questionable to deliberately perform capsulotomy for the sake of ASOT. First, the intact capsule is an important biological barrier between the AC and VC. Second, ASOT means completely sacrificing the opportunity for future intracapsular intraocular lens implantation, and almost all intraocular lens on the market are designed for intracapsular implantation. Third, a larger iridotomy should be performed and this indicated additional tissue damage and potential visual distractions. We can achieve partial ASOT filling effect by AC paracentesis to release part of the AC volume so as to increase the volume of the VC. We can also set the intraocular pressure to 10 mm Hg in the late stage of SO infusion, so that the SO could flow back into the infusion channel after filling the VC. Then, we can raise the pressure to 40 or even 50 mm Hg to force the SO into the VC again (Supplementary Digital Content Fig. 1, https://links.lww.com/APJO/A172). Elevated intraocular pressure usually returns to normal quickly with prone position.
• We believe that early postoperative posture is more critical than the additional 260 µL of SO. Because no matter prone position, left-side or right-side decubitus position, the inferior retinal quadrants could be supported by SO unless there is a serious shortage. Therefore, the regular adequate silicone oil tamponade in Supplementary Digital Content Figure 1 (https://links.lww.com/APJO/A172) is only applicable in the standing position, and any other posture will completely change the interaction between the inferior retinal quadrants and SO.
• We also disagree with the description of ASOT in Supplementary Digital Content Figure 1 (https://links.lww.com/APJO/A172). The aqueous humor is generated from the ciliary body behind the iris. Therefore, unless the prone position is maintained, the aqueous humor will first enter the posterior chamber and VC under the gravity, filling the space not occupied by SO. Excess aqueous humor enters the AC through iridotomy at the 6 o’clock position only when the VC is completely filled with SO and aqueous humor.

In conclusion, ASOT should be attempted in patients highly suspected of having significant vitreous underfilling and accidental capsule rupture. In view of the above reasons, we suggest that ASOT should not be considered a mature and worthy technique, and its comprehensive clinical evaluation requires more carefully designed clinical studies.

Lei Gao, MD*†

Chunzhu Han, MD‡

Hongmin Yu, MD§

*Department of Ophthalmology, Weifang Eye Hospital, Zhengda Guangming Eye Group, Weifang, China

†Zhengda Guangming International Eye Research Center, Qingdao University, Qingdao, China

‡Department of Ophthalmology, Maternal & Child Health Hospital of Zhifu, Yantai, China

§Department of Ophthalmology, Zhaoyuan People’s Hospital, Yantai, China