A method of measuring and / or detecting the activity of hydrolytic isomers, including: (a) associating cells expressing lecitina retinol aciltransferasa (LRAT) with a viral adenosine vector (AAV), which includes a transfer encoding a hydrolytic protein, such as, RPE65) under the condition that cell conduction is allowed; (b) under the condition that protein expression is allowed, conducting cells are cultivated; (c) conducting cells are collected and analyzed to produce extracts including proteins; (d) extract is transmitted with matrix at the time and condition allowed. From the base to the protein,a. A reaction product; (E) the reaction product is placed under the column chromatography to produce a pure reaction product; and (f) the former product is placed under the mass spectrometry to quantify the reaction product so as to measure the activity of hydrolyzed isotopes.Referido a un metodo para medir y/o detectar la actividad de isomero hidrolasas, que comprende: (a) poner en contacto celulas que expresan lecitina retinol aciltransferasa (LRAT) con un vector viral adenoasociado (AAV) que comprende un transgen que codifica una proteina isomero hidrolasa (tal como, RPE65) bajo condiciones que permiten la transduccion celular; (b) incubar las celulas transducidas bajo condiciones que permiten la expresion de la proteina; (c) recolectar y lisar las celulas transducidas para producir un extracto que comprende la proteina; (d) incubar el extracto con un sustrato durante un periodo y bajo condiciones que permiten la conversion del sustrato por la proteina, a un producto de reaccion; (e) someter el producto de reaccion a cromatografia de columna, obteniendose un producto de reaccion purificado; y (f) someter el anterior producto a espectrometria de masa, cuantificandose el producto de reaccion, midiendose asi la actividad del isomero hidrolasa.