Ukuhlolwa kombono, ukuhlolwa kwe-Ishihara kuthakasela kakhulu umbono wemibala. Namuhla kuwukuhlola okusetshenziswa kakhulu emhlabeni wonke ukuxilonga izinhlobo ezahlukene zokungaboni ngemibala.

Njengoba kwacatshangwa ngo-1917 uprofesa waseJapane u-Shinobu Ishihara (1879-1963), ukuhlolwa kwe-Ishihara kuwukuhlola kwe-chromatic ukuhlola umbono wemibala. Kwenza kube nokwenzeka ukuthola ukwehluleka okuthile okuhlobene nokubona kombala (dyschromatopsia) ngokuvamile okuqoqwe ngaphansi kwegama elithi ubumpumputhe bombala.

Ukuhlolwa kwakhiwe amabhodi angu-38, akhiwe nge-mosaic yamachashazi anemibala ehlukene, lapho ukwakheka noma inombolo ivela ngenxa yeyunithi yemibala. Ngakho-ke isiguli sivivinywa ikhono laso lokuqaphela lesi simo: umuntu oyimpumputhe wombala akakwazi ukuhlukanisa umdwebo ngenxa yokuthi akawuboni umbala wawo ngendlela efanele. Ukuhlolwa kuhlukaniswe ngochungechunge oluhlukene, ngakunye kuqondiswe kokudidayo okuthile.

Ukuhlolwa kwenzeka ehhovisi le-ophthalmology. Isiguli kufanele sigqoke izibuko zaso ezilungisayo uma sizidinga. Womabili amehlo avame ukuhlolwa ngesikhathi esisodwa.

Amapuleti ethulwa ngokulandelana kwelinye esigulini, okufanele sikhombise inombolo noma ifomu alihlukanisayo, noma ukungabikho kwefomu noma inombolo.

Ukuhlolwa kwe-Ishihara kunikezwa uma kukhona izinsolo zokungaboni umbala, isibonelo emindenini engaboni umbala (okungavamile okuvame ukuvela ngenxa yofuzo) noma phakathi nokuhlolwa okuvamile, isibonelo emnyango wesikole.

Imiphumela yokuhlolwa isiza ukuhlonza izinhlobo ezihlukene zokungaboni umbala:

• i-protanopia (umuntu akaboni okubomvu) noma i-protanomaly: umbono wokubomvu uyancipha
• i-deuteranopia (umuntu akaboni okuluhlaza) noma i-deuteranomaly (umbono wokuluhlaza uyancipha).

Njengoba ukuhlolwa kuyikhwalithi futhi kungeyona ingxenye, akwenzi kube nokwenzeka ukuthola izinga lokuhlaselwa komuntu, ngakho-ke ukuhlukanisa i-deuteranopia kusuka ku-deuteranomaly, isibonelo. Ukuhlolwa kwe-ophthalmologic okujulile kuzokwenza kube lula ukucacisa uhlobo lobumpumputhe bombala.

Ukuhlola nakho akukwazi ukuhlonza i-tritanopia (umuntu akawuboni umhuzuko kanye ne-tritanomaly (ukuncipha kokubona okuluhlaza okwesibhakabhaka), okuyivelakancane.

Akukho ukwelashwa okwamanje okwenza kube nokwenzeka ukudambisa ubumpumputhe bombala, okungaphezu kwalokho okungabangeli ngempela ukukhubazeka kwansuku zonke, futhi akuguquli ikhwalithi yokubona.