Indian cricket greats Sunil Gavaskar and Kapil Dev joined a dozen other former international captains on Tuesday in demanding better prison treatment for "one of the finest all-rounders" of the game, Imran Khan.

Cricketer-turned-politician Khan, 73, has been in jail since August 2023, convicted in a string of cases that he says were politically driven following his ouster in a 2022 parliamentary vote.

Khan's lawyer told the Supreme Court last week that the ex-cricketer had lost a significant amount of vision in his right eye while in custody. A medical board said on Monday the swelling had reduced after treatment and his vision had improved.

Former Indian captains Gavaskar and Kapil also signed the petition expressing "deep concern" about Khan's treatment and prison conditions.

"Many of us competed against him, shared the field with him, or grew up idolizing his all-round brilliance, charisma, and competitive spirit," they said in the petition.

"Recent reports concerning his health — particularly the alarming deterioration of his vision while in custody — and the conditions of his imprisonment over the past two and a half years have caused us profound concern.

"As fellow cricketers who understand the values of fair play, honour, and respect that transcend the boundary rope, we believe that a person of Imran Khan's stature deserves to be treated with the dignity and basic human consideration befitting a former national leader and a global sporting icon."

Former Australia captain Greg Chappell, his brother Ian Chappell and compatriots Allan Border, Steve Waugh, Belinda Clark and Kim Hughes have signed the petition.

England’s Mike Atherton, Nasser Hussain, Mike Brearley and David Gower have also signed, alongside Clive Lloyd from the West Indies and John Wright from New Zealand.

The cricket greats "respectfully" urged the Pakistan government to ensure immediate and adequate medical attention, dignified treatment, and unhindered access to legal processes for Khan.

"Our shared history on the field reminds us that rivalry ends when the stumps are drawn -- and respect endures. Imran Khan embodied that spirit throughout his career."

Khan played 88 tests and 175 one-day internationals for Pakistan between 1971-1992 and captained them to their only ODI World Cup victory in 1992.

His son Kasim Khan told Reuters the immediate concern was his father's health but there were other pressing issues including "his freedom, abiding by correct human rights processes and also the rule of law and just ensuring that he's allowed a proper, fair trial".