Comment on ‘Silicone oil removal after rhegmatogenous retinal detachment: comparing techniques’

Sir,

We would like to commend Tan et al¹ on their study comparing two methods of silicone oil removal. The paper succinctly describes different methods in removing silicone oil and its different advantages. However, it fails to convince the readers that two port removal is more advantageous as stated in the paper. First, there were only 10 cases which had less than 2 months of tamponade compared with 133 cases with longer than 2 months tamponade. This disproportionate number does not allow for accurate statistical analysis. The numbers also do not add up to the total 147 cases described. Also, 43% of 10 eyes is 4.3 eyes and it is difficult to understand how 0.3 eyes can have redetachment. Furthermore, there lacks a multiple regression analysis of the various factors described such as presence of PVR in the two groups and repeat surgeries in the two groups as it is well known that these factors influence the success of retinal detachment surgery. There is also a discrepancy where the authors have excluded patients with macular pucker before extraction, but further described 38 of 52 (73%) of 3 port extraction cases undergoing membrane peeling. The authors have also stated two advantages of the three port technique: (1) ability to perform extensive internal search and (2) improved oil removal. Herbert et al² reported retinal redetachment rate of 21% following removal of silicone oil with internal search. This is not significantly lower than other published rates of redetachment following oil removal. However, the paper also describes the identification of new retinal breaks in 35% of eyes (only 4% by Tan et al¹). With this high incidence of new break identification, one would have thought that the retinal redetachment rate for the two port technique would be significantly higher than the three port technique. Tan et al¹ found a higher redetachment rate (21%) in the three port technique compared with the two port technique (14%). In summary, from the data provided it is difficult to conclude that the two port technique is more cost-effective.