Sir,

Increased vascular endothelial growth factor (VEGF) production has been reported in central retinal vein occlusion (CRVO), which could be due to peripheral retinal ischemia.1 Panretinal laser photocoagulation (PLP) in peripheral retina has been shown to reduce the VEGF production.2 Here, we report 1-year results of a prospective randomized single-masked trial comparing 1.25 mg intravitreal bevacizumab pro-re-nata (PRN) monotherapy and PRN therapy in combination with PLP at 1 month in treatment of naive eyes with macular edema (ME) secondary to CRVO.

Naive eyes with center-involving ME secondary to CRVO of <9 months duration, minimum central subfield thickness (CST) of 250 μm on spectral domain optical coherence tomography, and best-corrected visual acuity of 24–73 letters were included. Subjects were randomized to either monotherapy or combination group. Through month 12, subjects were evaluated monthly and treated with intravitreal injections on a PRN basis as per predefined retreatment criteria. Seven field fluorescein angiography and electroretinography (ISCEV standards) were performed at baseline, month 6 and month 12. Wilcoxon signed-rank test was performed to evaluate changes in visual acuity and CST.

Twenty-two eyes of 21 consecutive subjects were enrolled. Baseline characteristics of both groups are shown as Table 1. Mean change in visual acuity in monotherapy and combination group at the last visit from baseline was 24.61 (P=0.001) and 25.49 (P=0.001) letters, respectively (P=0.32). Mean decrease in CST in monotherapy and combination group at the last visit from baseline was 515±202 (P=0.0002) and 642±224 (P=0.0003) microns, respectively (P=0.3) (Figure 1). Mean number of injections in monotherapy and combination group was 6.0±3.17 and 6.7±3.59, respectively (P=0.33). There was no significant difference in b/a ratio on ERG between two groups.

Table 1 Baseline characteristics of study groups
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Figure 1
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(a) Mean change from baseline best-corrected visual acuity in Early Treatment Diabetic Retinopathy Study (ETDRS) letters over time to month 12. The last-observation-carried-forward method was used to impute missing values. Improvement in visual acuity during the treatment period was maintained in both groups till month 12 with no significant difference between the two groups (P=0.32). (b) Mean change from baseline CST in microns over time to month 12. The last-observation-carried-forward method was used to impute missing values. Decrease in CST during the treatment period was maintained in both groups till month 12 with no significant difference between the two groups (P=0.3).

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Spaide3 reported outcome of 10 eyes, which underwent peripheral laser photocoagulation during the treatment with ranibizumab. He reported no difference in the number of injections (3.4 vs 3.1) 6 months before and after peripheral laser photocoagulation. Similar to our results, RETAIN and RELATE trials also reported no benefits of PLP.4, 5

In conclusion, early PLP in eyes with CRVO neither shows additional benefits on functional outcome nor to reduce the number of injections during the 1-year follow-up.

Study group investigators

Divya Balakrishnan, Subhadra Jalali, Navakanth Bandi, Anand Partani, Sripathi Kamath, Devendra Venkatramani, Aditya Sudhalkar, Devendra Phalak, Padmaja K Rani, Piyush Bansal, Rajeev Reddy, and Archana Bhargava.