Abdullah Ibn Masood (ra) has narrated that the Prophet of Allah sallallaahu `alyhi wa salam said: Allah’s curse is on those women who practice tattoing and get themselves tattoed and those who remove hair from their faces and those who create spaces between their teeths artificially to look beautiful and those women who change their features created by Allah (swa) (Bukhari p.878 v.2)

Any thing which alter or change the facial qualities of a person is prohibited as mentioned in the aforementioned hadith.
Coloured contact lenses are things which do not alter the facial expression of a man or woman, hence, it will be permissible for them to wear it.

However, care should be taken by women that it is not worn in front of ghair mahram men.

ANSWER 2

Regarding the masala whether a person who has a mortgage is liable to pay Zakat or not.

Imam Abu Hanifa has said that long term debts do not prevent Zakat. al-Quhustani added that this is the more correct position in the Madhhab.” (Radd al-Muhtar, 2/261)

The ruling in light of the aforementioned masala will be that if you have the means and you are financially able to pay off the mortgage, then you must do that as soon as possible, hence, the question of zakat will not be applicable.

However, if you are unable to pay off your mortgage all at once, then you may deduct only that amount which is immediate. The mortgage will be paid in instalments and on a long term basis. In the light of the more preferred opinion in the school, you should avoid deducting the whole sum, which is payable by you. Only the payment which is currently due should be deducted from the total. (Jadeed Fiqhi Massail p.213 v.1)

Mohammed Tosir Miah
Darul Ifta Birmingham.