Discussion
ROP continues to be a major cause of visual impairment in children. Data from different neonatal intensive care units (NICU) in Latin America show that up to 11–13% of premature infants will need laser treatment. Retinal ablation can significantly reduce unfavourable visual acuity and structural outcomes, but was found to have only limited efficacy in posterior disease. This treatment also has undesirable side effect such as visual field loss, myopia and cataract.
Off label use of intravitreal bevacizumab has recently emerged as an important and promising yet controversial treatment option in ROP. It is a short and easy procedure, does not require special equipment and can be carried out with short acting topical anaesthesia and so avoiding general anaesthesia or sedation. It is of special interest in premature infants in NICU's with other co morbidities.
Ranibizumab is a specifically designed recombinant humanised antibodies that bind and inhibit all biologically active VEGF isoforms. It has a decreased systemic half life and a higher binding affinity than bevacizumab, making it potentially more favourable in the treatment of infants with ROP with regard to efficacy, ocular health and systemic safety profile.
In the present study, ranibizumab effectively inhibited NV in patients with high risk prethreshold and threshold ROP with plus disease, with prompt regression after one injection and no early or late recurrence. Our results are comparable with previously published data on the effectiveness of bevacizumab in ROP.
Unlike laser, anti VEGF treatment does not involve the destruction of the peripheral retina. It allowed for continued vessel growth into the peripheral retina in all study eyes starting a few weeks after the injection, thus avoiding some of the late complications of ablative treatment. All study eyes had favourable anatomical outcome without any signs of retinal detachment, macular dragging or folds after 3 years.
The preserved visual acuity, with an average Snellen equivalent of 20/30, that we found at 3 years of age, can imply on ocular growth and function.
Although we did not find any ocular or systemic adverse events, this study is too small to address any safety issues.
In conclusion, 3 years of follow up in a small series suggest that intravitreal ranibizumab injections for ROP result in apparently preserved ocular outcome. Further large scale studies are needed to address the long term safety and efficacy of ranibizumab in the treatment of ROP.