My father, Neil McLachlan, who has died suddenly aged 81, was completely blind from his late 30s as a result of the inherited condition retinitis pigmentosa, but he never let his blindness prevent him from leading a fiercely independent life.
For nearly 30 years, he worked as a research scientist at British Steel, devising complex data models to improve the manufacturing process. In 1990, he and two other blind people achieved a world record for blind mountaineering, climbing to an altitude of 6,476m (21,250ft) – in a team with nine sighted climbers – when they reached the summit of Mera Peak in the Himalayas, despite extremely hostile conditions.
