Police said at least 157 people had undergone the surgery at a village camp run by a medical charity early last month and 20 confirmed cases of blindness had been identified.
Media reports have indicated the number left blind could be as high as 60.
“There are about 20 confirmed cases of patients from the camp who have lost their eyesight,” said Manvinder Singh, a senior police officer in the northern state of Punjab, where the camp was held.
“We are investigating the rest,” he told AFP.
Singh said that the doctor who conducted the surgeries and the organiser of the camp had been taken into custody and were being questioned, but had not been formally charged.
The case raises fresh concerns over the quality of medical procedures in India after the deaths of 13 women who underwent sterilisation surgery at a camp in central India.
Government officials have blamed contaminated drugs for their deaths, but an independent report published this week said they had suffered septicaemia. Doctors allegedly used the same unsterile equipment on dozens of women.
A government doctor who treated the latest victims said they had contracted infections after undergoing the cataract surgery on November 4.
“They came to us in a very bad condition… the infection had already spread,” Karanjeet Singh told the NDTV news channel, adding that the “chances of restoring their eyesight” were much lower now.
Authorities said the problem first came to light when victims began coming forward this week. They have since been admitted to a government hospital.
Ravi Bhagat, a deputy commissioner in neighbouring Amritsar district told AFP that the camp was operating without government permission and authorities had registered a legal case against the Guru Nanak Charitable Hospital where the surgeries were conducted.
AFP was not immediately able to reach the hospital administration for comment.