It is a diagnostic exam which is performed to evaluate the function and integrity of the optic nerve fibers from the eye to the occipital cortex of the brain, otherwise known as the visual system. The nerve fiber layer is distributed throughout the back of the eye. These fibers “captures the images of what we are seeing” and converts them to electric signals which are then sent to the brain. When there is damage to the nerve fiber layer or along the visual pathway, suggestive patterns of damage localization and severity can be seen with this study.

This exam is useful because it not only helpful in detecting optic nerve pathology such as glaucoma, but also neurological diseases such as multiple sclerosis or tumors of the optic chiasm.

This exam requires a minimum amount of vision and a contact lens is frequently used. The duration of the exam is around 8 minutes per eye.

A sophisticated computer analysis software using an algorithm will stimulate the nerve fiber layers through luminous stimuli. The program will vary the light stimulus to measure damage in each sector of the visual field. These light stimuli are measured in light decibels. Normally, the areas around the fovea are the most sensitive to light stimuli and the decibel number is higher.

When the exam is over, the results will be represented in a numeric and graphical image so that the ophthalmologist can interpret and determine: diagnosis, severity, prognosis and treatment options.

At Tijuana Eye Center, our perimetry systems are among the most advanced in the world for the diagnosis of glaucoma and neurological diseases. The advanced algorithms such as SITA-FAST, FASTPAC, SWAP, and GPA progression analysis help detect glaucoma patients earlier.

It is important to note that this examination is as useful as the technician who correctly performs the exam and the retina specialist who interprets the results.