The objective of the study was to investigate the behavior of ternary phase diagrams consisting of water, oil, and surfactant. The researchers aimed to identify and characterize the different phases obtained from combinations of oil and surfactant/cosurfactant mixtures (S-mix), including conventional emulsions, gel/viscous phases, and transparent/translucent nanoemulsions (NEns). To achieve this objective, the researchers constructed ternary phase diagrams using the water titration method at room temperature. They gradually added and mixed water into the system, and after each addition, they visually analyzed the resulting phases. The study utilized Opuntia Ficus indica seed (OFIS) oil as the oil phase, Tween-80 as the surfactant, PEG-400 as a co-solvent, and different proportions of S-mix (surfactant mixture), along with water as the third phase. By varying the ratios of the S-mix (which included Tween-80 and another surfactant), the researchers aimed to understand the effects on phase behavior, including the formation of emulsions, gels, and NEns. Specifically, they tested ratios of 1:0.5, 1:1, 1:11.5, 1:2, 1:2.5, and 1:3 for the S-mix composition. The study found that combinations of surfactant and co-surfactants (Tween 80: PEG-400) with OFIS oil resulted in high gel or viscous phases. Based on the ternary phase diagrams, the ratio of the S-mix (1:1) was identified as more suitable for formulating NEns, providing high stability and a large area of the NEn region.