Sir,

We read with great interest the article by Wu et al.1 We have some comments to share with the authors and to broaden the discussion.

First, the proportion of ischaemic central retinal vein occlusion (CRVO) was different in the two treatment groups. The ITA group had 13.6% (3/22) of ischemic CRVO patients, while the IBe group had 38.5% (5/13) of those patients. Although not statistically significant, the chi-square test showed a trend of difference in the constitution of CRVO patients (P=0.09). A previous study had shown that intravitreal injection of triamcinolone acetonide (TA) might be more favourable to non-ischaemic CRVO.2 The results of the present study also imply that non-ischaemic CRVO may have a better outcome than intravitreal injection of bevacizumab. The difference in constitution of ischaemic/non-ischaemic CRVO patients in the two treatment groups might lead to the conclusion that IVTA was as effective as intravitreal injection of bevacizumab in treating macular oedema because of CRVO being less convincing.

Second, we are curious about the choice of dosage of the TA. The SCORE study has shown the same efficacy of 1 and 4 mg TA in improving visual acuity in perfused CRVO patients, but lesser intraocular pressure (IOP) elevation and cataract with 1 mg TA.3 Although during the time of the authors’ study, the results of the SCORE study were not available, the authors may need to specify their reasons for choosing 4 mg TA as the dosage.

Third, the authors used a full auto tonometer to measure the IOP instead of the Goldmann applanation tonometer, which is the golden standard in IOP measurement. We are wondering about the reasons behind the choice of the tonometer in this study.

Fourth, in the patient who had mature cataract during follow-up, the authors did not describe the appearance of the cataract, nor did they state how fast the cataract developed. This information was important for us to determine whether the cataract was caused by the needle during injection.