Google has introduced a new feature to its Google Glass, which allows users to take a photo with a "wink of the eye".
Google said the feature was faster than the camera button or the voice action and works even when the display is off.
The update to Google Glass, dubbed version XE12, also adds a screen lock feature and the ability to upload and share videos on YouTube.
Technology firms have been keen to capture the wearable gadgets market, seen by many as a key growth area.
Google said the wink feature in its Glass could have various other uses in the future.
"Imagine a day where you're riding in the back of a cab and you just wink at the meter to pay," the firm said in a blogpost.
"You wink at a pair of shoes in a shop window and your size is shipped to your door. You wink at a cookbook recipe and the instructions appear right in front of you - hands-free, no mess, no fuss," it added.
The launch of Google Glass was accompanied with concerns over its impact on privacy. The worries were triggered by its potential to gather images, video and other data about almost anything a user sees.
Some have argued that privacy will be "impossible" if Google Glass and similar products become widely used.
Analysts said the ability to take a photo by just winking an eye would make it very difficult for people being photographed to notice that someone had taken a picture of them.
"It is a remarkable progress of technology and the possibilities of innovation around it limitless," Manoj Menon, managing director of consulting firm Frost & Sullivan.
"However, it comes with new issues that we need to understand, not least the worries over security and privacy.
"There needs to be discussion about how, and in what environments, gadgets like these can be used openly," he said.
Mr Menon added that as the technology behind these gadgets matures and companies push more for their mainstream adaption, regulations were likely to come into place "to govern their usage".
The wearable technology market is expected to see robust growth in the coming years.
However, analysts differ over the potential size of the market.
According to Juniper Research, the sector is expected to have annual sales of $19bn (£11.9bn) by 2018, up from $1.4bn this year.
Analysts at the bank Credit Suisse have been more upbeat and have suggested a figure of $50bn figure by the same date.
Research firm Gartner has been more cautious about its predictions. It has said it expects $10bn sales for 2016. But one of its analysts suggested the sector would grow more quickly if businesses decided to equip their workers with such technology.
Google Glass is one of a number of wearable gadgets that have been launched by firms as they compete to take a a major share of the growing market.
In October, Nike launched its second generation wristband, Fuelband, which helps users track their physical activity.
In September, Samsung unveiled a smartwatch, Galaxy Gear, that can be used for voice calls and run apps.
Also in September, Japanese mobile operator NTT Docomo demonstrated glasses that can translate a menu by projecting an image of translated text over unfamiliar characters.
Earlier this year, US-based Heapsylon said it was developing sensor-equipped socks that would help their owners monitor their balance while walking or running.
Meanwhile, Chinese firm Shanda, has unveiled the Geak Ring - a finger-worn device that can unlock a user's smartphone or pass data to others.