The decrease in visual acuity can be caused by various factors affecting our vision, which can be caused by different causes, among the most frequent being the insertion of an organic foreign body. In other words, it is one of the main causes of partial or total vision loss and if not treated in time can cause severe damage to our vision. The objective of this study is to establish and specify the cause of the decrease in vision with the respective visual assessment tests, which includes visual acuity both at a distance (6m) and near (35-40 cm). When observing that the patient did not improve his visual acuity with refraction, he was referred to the ophthalmologist who determined that his problem was due to a decrease in distant visual acuity, foreign body sensation, blurred visión, ocular burning after ocular trauma with a metallic object which did not allowed the images to reach the retina correctly.The decrease in visual acuity can be caused by various factors affecting our vision, which can be caused by different causes, among the most frequent being the insertion of an organic foreign body. In other words, it is one of the main causes of partial or total vision loss and if not treated in time can cause severe damage to our vision. The objective of this study is to establish and specify the cause of the decrease in vision with the respective visual assessment tests, which includes visual acuity both at a distance (6m) and near (35-40 cm). When observing that the patient did not improve his visual acuity with refraction, he was referred to the ophthalmologist who determined that his problem was due to a decrease in distant visual acuity, foreign body sensation, blurred visión, ocular burning after ocular trauma with a metallic object which did not allowed the images to reach the retina correctly.La disminución de la agudeza visual se puede producir por diversos factores afectando nuestra visión se pueden dar por varias causas entre las más usual es por la inserción de un cuerpo extraño corneal o conjuntival. En otras palabras, es una de las principales causas de perdida de la visión parcial o total sino es asistida a tiempo puede causar daños severos en nuestra visión. El objetivo de este estudio es establecer y precisar la causa de la disminución de la visión con los respectivos exámenes de valoración visual en lo que se incluye la agudeza visual tanto de lejos (6m) y de cerca (35 – 40 cm). Al observar que el paciente no mejoraba su agudeza visual con la refracción se derivó al oftalmólogo quien determino que su problema se debía a disminución de agudeza visual debido al cuerpo extraño orgánico alojado en el ojo del paciente lo cual no permitía que las imágenes lleguen correctamente a la retina.