I read with interest the announcement of iris scanning for identification purposes by the Immigration and Checkpoints Authority ("ICA to start collecting iris images for border clearance"; yesterday).
As an ophthalmologist, I have no doubt about the accuracy of iris imaging for identification purposes.
But the permanence of the human iris configuration is not a given.
The iris can be affected by eye diseases such as eye inflammation, and pigmentary and vascular disorders.
Episodes of extreme eye pressure elevation (glaucoma) can also affect iris muscles, and hence affect the appearance of the iris.
Furthermore, eye doctors often perform laser surgery on the iris for the treatment of glaucoma, effectively puncturing a hole or creating contractile scars on the iris to alleviate eye pressure.
In some unique cases, we even have to affix artificial lenses on the iris. Complications of eye surgery can also cause iris scars or defects.
Eye trauma is another instance where the iris may be altered.
Although milder cases may be imperceptible, severe injuries may require iris repair surgery, some to the extent of requiring implantation of artificial irises.
The advancement in artificial irises has been a milestone in eye reconstruction surgery.
State-of-the art artificial irises can now be matched both in colour and detail to another eye. Such artificial irises restore not only vision and visual quality, but also appearance and self-confidence, particularly in eyes with light-coloured irises.
I hope that the authorities are cognisant of the developments in the medical field with regard to eye diseases and treatments involving the iris.
When the need arises, the public may require the necessary support from their eyecare providers for certification of identity, such as in the event of eye disease, injury and treatment.
Daphne Han Chuk Yin (Dr)
Reply: Iris images to complement other forms of identification
We thank Dr Daphne Han Chuk Yin for her feedback ("Iris can be altered by disease, injury, treatment"; Nov 12).
The Immigration and Checkpoints Authority (ICA) recognises that different personal biometric identifiers come with their own unique characteristics, as well as inherent limitations.
For instance, fingerprints can fade over time, while a person will also look different with age.
This is why it is important for the ICA to adopt a multi-modal approach to biometrics. The use of iris images complements existing identification methods using fingerprints and facial images, and will help strengthen the identification process.
For people whose iris images cannot be effectively scanned or enrolled due to disease or surgery, the ICA will rely on these other identifiers to verify their identity.
Brenda Tham (Ms)
Public and Internal Communications
Corporate Communications Division
Immigration and Checkpoints Authority