[Toluena adalah bahan kimia yang banyak digunakan sebagai bahan dasar danpelarut di bidang industri. Toluena bersifat neurotoksik, dapat menembus sawardarah-akson sehingga dapat menyebabkan gangguan di sistim saraf pusat sertasaraf tepi termasuk di saraf optik. Pada penelitian sebelumnya pajanan inhalasikronis toluena dosis tinggi pada tikus dapat meningkatan kadar malondialdehyde(MDA). Penelitian eksperimental ini bertujuan untuk mengetahui efek pajanantoluena terhadap saraf optik, dengan pemeriksaan kadar MDA plasma, MDAsaraf optik dan histopatologi saraf optik.Tiga puluh tikus wistar jantan dibagi menjadi lima kelompok, yaitu kelompokkontrol, kelompok pajanan toluena 12.5 ppm, 25 ppm, 50 ppm, dan 100 ppmselama 4 jam/hari dalam waktu 2 minggu. Kondisi lingkungan dipertahankanpada suhu berkisar 25oC-32oC dengan kelembaban relatif 30%-70 % Pemeriksaankadar MDA plasma dan MDA saraf optik dilakukan dengan metodeThiobarbituric Acid Reactive Substances (TBARS). Penilaian histopatologis sarafoptik dengan pewarnaan biru toluidin dan mikroskop cahaya.Dari hasil penelitian ditemukan perbedaan median nilai histopatologi saraf optik(p<0.001) yang bermakna antar kelompok. Nilai histopatologi saraf optik mulaimenunjukan perbedaan bermakna pada kelompok dengan pajanan toluena 50ppm. Tidak terdapat perbedaan rerata kadar MDA saraf optik yang bermaknaantar kelompok pajanan toluena (p=0.056). Pajanan toluena menyebabkandegenerasi akson dan fibrosis pada saraf optik tikus., Toluene is a widely used chemical, mostly as basic material and as a solvent inindustry. Toluene is neurotoxic, can penetrate the blood-axons barrier that cancause disturbances in the central nervous system and peripheral nerves includingthe optic nerve. In previous study, chronic inhalation exposure of rats to toluenein high doses can cause elevated levels of malondialdehyde (MDA). Theobjective of this experimental study is to determine the effects of tolueneexposure in the optic nerve, by examining the levels of plasma MDA, optic nerveMDA and optic nerve histopathology.Thirty male wistar rats were divided into five groups: control group, 12.5 ppm,25 ppm, 50 ppm, and 100 ppm toluene exposure groups, exposure was 4hours/day for a period of 2 weeks. The environment (temperature and humidity)was kept in 25oC-32oC and 30%-70%. Measurement of plasma MDA and opticnerve MDA level was conducted by using Thiobarbituric Acid ReactiveSubstances (TBARS). The optic nerve histopathologic was assessed by usingtoluidine blue staining and light microscopy.The result showed there were significant differences in the optic nervehistopathology score (p<0.001) between groups. Optic nerve histopathologyscore began to show significant differences in the group with 50 ppm tolueneexposure. No significant differences were found in the mean levels of optic nerveMDA between groups (p=0.056). Toluene exposure causes degeneration of axonsand fibrosis in the rat optic nerve.]