Characteristics of ‘sawtooth shunt’ following anti-vascular endothelial growth factor for aggressive posterior retinopathy of prematurity

  • Tapas Ranjan PadhiEmail author
  • Taraprasad Das
  • Prabhjot Kaur
  • Samir Sutar
  • Ashish Khalsa
  • Rohit Modi
  • Hasnat Ali
  • Lingaraj Pradhan
  • Subhadra Jalali
Original Paper



To explore the characteristics of ‘sawtooth shunts (STS)’ following intravitreal anti-vascular endothelial growth factors (anti-VEGF) for aggressive posterior retinopathy of prematurity (AP-ROP).


Prospective observational study.


In a prospective observational study, 45 eyes of 24 babies receiving intravitreal anti-VEGF for AP-ROP or hybrid ROP were analyzed. Anti-VEGF molecule and doses: bevacizumab (0.62 mg or ½ IVB, n = 30 eyes; 0.25 mg or 1/5IVB, n = 9 eyes; 0.12 mg or 1/10 IVB, n = 1 eye); or ranibizumab (0.25 mg or ½IVR, n = 3 eyes; 0.1 mg or 1/5IVR, n = 2 eyes). They were followed every 1–2 week till disease regression with or without laser treatment. Development of STS, its variants, characteristics, timeline, and final outcomes was analyzed.


STS occurred in 26 (57.7%) eyes at 1–6 weeks following anti-VEGF injections and persisted for 1–14 weeks. While the shunt regressed spontaneously in half of the treated eyes (n = 13) with anti-VEGF alone, the other half (n = 13) required additional laser because of either non-compliance (n = 9) or recurrence (n = 4).


The STS was observed to be an important retinal vascular change seen in infants treated with intravitreal anti-VEGF at half adult doses. It warrants further studies to explore the association between STS and its association with disease recurrence or regression.


Retinopathy of prematurity Aggressive posterior retinopathy of prematurity Intravitreal anti-vascular endothelial growth factors Retinal vascular changes Sawtooth shunt 


Author contributions

All authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by Tapas Ranjan Padhi, Prabhjot Kaur, and Ashish Khalsa. The first draft of the manuscript was written by Tapas Ranjan Padhi, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.


There is no direct support or grant related to this piece of work. However, the authors belong to an institute that receives support from Queen Elizabeth Diamond Jubilee Trust (UK), Miriam Hyman Memorial Trust (UK), Rastriya Bal Swasthya Karyakram (RBSK), and Dalmia holdings in India for its ongoing ROP work.

Compliance with ethical standards

Conflict of interest

The authors declare no conflicts of interest.


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Copyright information

© Springer Nature B.V. 2020

Authors and Affiliations

  1. 1.Faculty, Vitreoretinal ServicesLV Prasad Eye InstitutePatia, BhubaneswarIndia
  2. 2.Srimati Kanuri Santhamma Centre for Vitreoretinal DiseasesLV Prasad Eye InstituteHyderabadIndia
  3. 3.Department of BiostatisticsLV Prasad Eye InstituteHyderabadIndia
  4. 4.Department of Pediatrics, Infosys Pediatric DepartmentCapital HospitalBhubaneswarIndia

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