Lalit Dandona|Rakhi Dandona
Revision of visual impairment definitions in the International Statistical Classification of Diseases
Administrative Staff College of India|Administrative Staff College of India
existing definitions visual impairment international statistical classification diseases based recommendations made 30 years ago new data knowledge related visual impairment accumulated period suggest definitions need revisedthree major issues need addressed revision definitions first existing definitions based bestcorrected visual acuity exclude uncorrected refractive error cause visual impairment leading substantial underestimation total visual impairment burden 38 second cutoff level visual impairment define blindness international statistical classification diseases visual acuity less 360 better eye increasing human development visual acuity requirements also increasing suggesting level less 660 used define blindness third international statistical classification diseases uses term low vision visual impairment level less blindness causes confusion common use term uncorrectable vision requiring aids rehabilitation suggesting alternative terms moderate mild visual impairment would appropriate visual impairment less severe blindness propose revision definitions visual impairment international statistical classification diseases addresses three issues according revised definitions number blind persons world defined presenting visual acuity less 660 better eye would 57 million compared world health organization estimate 37 million using existing international statistical classification diseases definition bestcorrected visual acuity less 360 better eye number persons world moderate visual impairment defined presenting visual acuity less 618 660 better eye would 202 million compared world health organization estimate 124 million persons low vision defined bestcorrected visual acuity less 618 360 better eyeour suggested revision visual impairment definitions international statistical classification diseases takes account advances understanding visual impairment revised classification seems appropriate estimating tracking visual impairment countries regions world existing classification international statistical classification diseases