Robert E. MacLaren (born 14 November 1966) is a British ophthalmologist who has led pioneering work in the treatment of blindness caused by diseases of the retina.

[7] MacLaren has been a Consultant Ophthalmic Surgeon for the Oxford University Hospitals NHS Foundation Trust (OUH) since March 2009.

He has been a Fellow of the Royal College of Surgeons of Edinburgh (RCSEd) since July 1998 and was awarded their annual King James IV Professorship in 2007.

[7] Key events of his work at the Moorfields and John Radcliffe hospitals include: MacLaren was the assistant surgeon to James Bainbridge and helped perform the world's first retinal gene therapy treatment.

[9] The delicate operation required passing a needle through the eye, to lift the retina and insert the new gene-copy in the pigment layer.

On 24 November 2011, Jonathan Wyatt, a Bristol barrister, received a 'good copy' of the REP1 gene, administered through an adeno-associated virus (AAV) – serotype 2 (AAV2) – as a vector, in fluid under the retina.

By 2016, the results of the trial appeared both 'promising and lasting' and further work was authorised, with a view to seeing whether the process could eventually be applied to more common conditions, such as age-related macular degeneration (AMD).

The main operation was undertaken, at Oxford, by MacLaren with Tim Jackson, consultant surgeon at Kings College Hospital.

He warned that current devices were not suitable to treat age-related macular degeneration (AMD) or diseases of the optic-nerve, such as glaucoma.

[13] The following week, Jackson, with MacLaren, operated on Robin Millar, a music-producer, in London; another four UK patients also received the device during that year.

This operation was described as the 'R2D2 Trial', because it was testing the safety and efficacy of the Robotic Retinal-Dissection Device (R2D2), developed by Dutch firm Preceyes BV (pronounced: precise!).

[17] The operation proved the efficacy of the new technologies available, allowing the possibility of exploiting their potential to new scientific and a medical ends: MacLaren said that with robotic systems, a whole new chapter of eye surgery had just begun.

Using a form of gene editing known as codon-optimisation, MacLaren and members of his research team were able to engineer a stable version of RPGR that was expressed highly efficiently in an AAV vector.

[2] Between March 2001 and April 2006, MacLaren was a Resident Clinical Research Fellow at the Moorfields Eye Hospital NHS Trust, in London.

[4] In 2014, with Oxford University, he co-founded the private bio-technology company NightstaRx Ltd.,[25] also known Nightstar, in which he remains a director, and which is based at the offices of the Wellcome Trust in London.

[31] MacLaren was posted to the Honourable Artillery Company (HAC) and, in due course, became the Surgeon-Major: the Regimental Medical Officer (RMO).

The term Surgeon-Major applied to all the unit's RMOs, most of whom were in General Practice (GP), and it was coincidental that Major MacLaren was primarily an occupational surgeon.