You can have a try to apply for Hong Kong visit visa in Istanbul, but your application maybe refused. You'd better apply for it in Uzbekistan, As an alternative, you may also submit your visa or entry permit application to the HKSAR Immigration Department either directly by post or through a local sponsor. To shorten the processing time, application forms and supporting documents can be sent by fax to (852) 2824 1133 in the first instance. However, the original copy of the duly completed application form and the photographs required should be sent immediately to the HKSAR Immigration Department by air mail. A visa/entry permit will be issued only on receipt of an original, properly completed visa/entry permit application form.