Blastoderm expression is anterior to that of so.

Optix transcripts are first detected in cellular blastoderm embryos in the anterior region in a sharply defined anterior stripe at 85-95% egg length. From gastrulation on, very dynamic expression is observed in a pattern that is generally symmetric about the dorsal midline. Some regions of expression include the labral segment and the procephalic neurogenic region. During germ band retraction, expression is seen in the cylpeo-labral region, in the supraoesophageal ganglion, and ventrally in the labial and maxillary segments. Dynamic expression continues after the germ band retracts. Some areas of expression include part of the pharynx, the supraoesophageal ganglion, the head sensilla, the frontal ganglion, and the frontal connective of the stomatogastric nervous system.

Optix transcripts are first detected at embryonic stage 5 in a band at 85-93% egg length. By stage 6, the expression has shifted to the dorsal-anterior region of the embryo. At stage 12, expression is observed in the clypeolabrum, the stomodeum, and in ectoderm dorsal to the future supraesophageal ganglion. The dorsal ectoderm has two bilateral sites of expression that might correspond to the eye-antennal disc primordia.

Optix is expressed throughout larval development in the Optix-expressing compartment of the outer optic anlage. Expression is also seen in glial cells and neuroblasts in the central brain.

In the early third instar larvae eye disc prior to morphogenetic furrow initiation, Optix is mainly detected interior of the eye field with little protein detected along the posterior and lateral margin of the discs where dpp is highly expressed. During morphogenetic furrow progression, Optix is mainly observed anterior to the morphogenetic furrow. However, a lower level of Optix protein is detected in dpp expressing cells at the anterior part of the morphogenetic furrow.

Most Optix is primarily expressed in the the type II neuron lineage in the adult brain.