BBC News website disability affairs correspondent
Some of the latest assistive technology for visually impaired people is on show at Vision 2005 - an international conference on all aspects of sight loss being held in London this week.
The Mobi-Click - also known as the SilverPhone - is a simplified mobile handset from Switzerland.
The Mobi-Click could appeal to parents and other carers
It has three large, coloured buttons which allow the user to dial three pre-programmed numbers as well as the emergency services.
"It was originally designed to give parents the ability to contact their children and keep tabs on their whereabouts," said RNIB product manager, Roger Bessent.
The phone can receive calls from any number, and can be programmed to alert a parent or carer when the user leaves a designated cell area.
Although its ability to keep track of a person's movements might raise fears among civil libertarians, Mr Bessent thinks it could have a legitimate use.
"In the case of vulnerable adults or children it might actually be very reassuring," he said.
The Mobi-Click can also be interrogated remotely to determine its battery status.
The phone can be used for 200 hours on standby and has 60 hours' talk time.
It is expected to sell for about £140.
At first glance the new Sonus 1XT made by Pure Digital looks like any other DAB radio.
The Sonus 1XT DAB radio speaks the time and the station ID
But this one gives an audio readout of the set's digital display.
The keypad functions are also "audio described" and a speaking clock can be activated by touching the carrying handle.
The Sonus also gives a voice readout of the scrolling text that most stations transmit to provide programme or track information.
But since this is spelt out letter by letter it can be a little hard to follow.
The Sonus 1XT costs £120, and if it is purchased from the RNIB it comes with a set of instructions in Braille.
Continuing the speech output theme, the Pan Opticus is a simple box that sits between a digital satellite receiver and a TV to read the on-screen menus.
The Pan Opticus gives a voice to Sky's electronic programme guide
The device reads all of the on-screen text including banners and programme synopses available via the info button.
The Pan Opticus is operated by the existing Sky remote controller and the speech output can easily be switched on and off.
It also alerts people when a programme is accompanied by audio description, subtitles or sign language.
Made by a company based in Suffolk, the Pan Opticus should be available later this year and will cost around £150.
People with low vision can access printed material relatively easily by using a CCTV video magnifier.
The MonoMouse is designed to be simple and low cost
But the cost of the devices can often be prohibitive.
With this in mind, Rutland-based company, Bierley, has produced the MonoMouse - a simple, handheld video magnifier that plugs into the Scart socket of a standard TV.
"We've had a phenomenal response since we launched it last November," said Mark Statham of Bierley.
"The reason people like it is because you just plug it in, turn it on and away you go - there are practically no instructions."
There are two versions of the MonoMouse - the less powerful one has a fixed magnification of 13 times on a 20" TV.
Its more powerful cousin magnifies text 24 times.
Mr Statham says that having a fixed magnification makes the device cheaper to manufacture and gives a sharper image.
On the lower magnification version, the CCTV device is more recessed which results in the enlarged text appearing slightly curved.
"Most people have found it acceptable," said Mr Statham.
The MonoMouse is also fitted with a diffuser in order to minimise glare when reading things like CD or DVD covers.
It comes with three metres of cable and costs £99.
Vision 2005 is at the Queen Elizabeth II Conference Centre in London from April 4-7.