World Cup-winning Indian captain believes Virat Kohli, who struggled in New Zealand across formats, needs to practise more as "his reflexes and hand-eye coordination are probably slowing down".

"When you reach a certain age, when you cross 30 then it affects your eyesight. In swings, which used to be his strength, he (Kohli) used to flick them four but now he has been dismissed twice. So I think he needs to adjust his eyesight a bit," Dev said on ABP news.

In the two Test matches, Kohli managed just 38 runs at an average of 9.50 -- his worst in recent times. He amassed a total of 218 runs in the 11 innings (four T20Is, three ODIs and four Tests) that he played against the Black Caps and ended a pathetic tour with just 14 in his last innings.

The end result was that the number one Test side had to face a crushing defeat at the hands of Black Caps, who made amends following their 5-0 whitewash in the T20Is and came back strongly to win the ODIs and the Test matches -- 3-0 and 2-0, respectively.

"When big players start getting bowled or LBW to incoming deliveries then you have to tell them to practise more. It shows that your eyes and your reflexes have slowed down a bit and in no time your strengths turn into your weakness.

"From 18-24, your eyesight is at the optimum level but after that, it depends on how you work on it," he added.

The legendary India skipper said that all players, including the likes of Virender Sehwag, Rahul Dravid, Vivian Richards, all faced similar difficulties in their career.

"So Kohli needs to practise more. When your eyesight weakens then you have to tighten up your technique more. The same ball which he used pounce on so quickly, he's getting late on it now," Dev said.

According to Kapil, Kohli should focus on getting his game back on track in the upcoming edition of the Indian Premier League which starts March 29.

"I think IPL will help him. He will start getting the hang of it. He's a great cricketer, he will definitely realize it himself and make adjustments," the 61-year-old former all-rounder said.

India will now take on South Africa in the three-match ODI series beginning March 12 in Dharamsala.