After pre and post-registration posts he began specialist training in 1987, working in Fife, the Sussex Eye Hospital, Brighton and the Princess Alexandra Eye Pavilion, Edinburgh.

He gained the Diploma in Ophthalmology from the Royal College of Surgeons of England (D.O., R.C.S.) in 1990, and fellowships of the Royal College of Surgeons of Edinburgh (F.R.C.S.Ed.) and the Royal College of Ophthalmologists (F.R.C.Oph.) in 1991.

Dr Whittle has been a permanent member of staff at the Princess Alexandra Eye Pavilion since 1995 where he is Associate Specialist and the director of the electodiagnostic service and also a supervising ophthalmolgist in the Lothian Optometry Teach and Treat Clinic.

Dr Whittle has been on the Ophthalmic List of Ophthalmic Medical Practitioners since 1994 and has been a member of the Lothian Local Ophthalmic Committee since 2010.

He is a member of the International Society for the Clinical Electrophysiology of Vision (I.S.C.E.V.). and the British Society for the Clinical Electrophysiology of Vision (Bri. S.C.E.V.)