Visually symptomatic multiple sclerosis (MS) provides only part of the required information to assist in understanding the disease. Recently, researchers have concentrated their efforts on diagnosing MS cases in the subclinical period. The aim of this paper was to assess visual fields and optical coherence tomography (OCT) measurements in patients with MS to detect subclinical visual system disease. The study included 15 MS patients with previous optic neuritis (Group I), 17 MS patients without previous optic neuritis (Group II), and 14 healthy controls (Group III). Each subject underwent standard automated perimetry (SAP), frequency doubling technology perimetry (FDTP), and OCT. The mean deviation of SAP in Group I was lower than those in Groups II (p = 0.018) and III (p = 0.001). The pattern standard deviation of SAP in Group I was higher than those in Group III (p < 0.0001). The mean deviation of FDTP in Groups I and II was lower than those in Group III (p = 0.0001 and p = 0.016, respectively). The temporal quadrant of the retinal nerve fibre layer in Group I was thinner than those in Groups II and III (p = 0.005 and p = 0.003, respectively). The mean macular volume in Group I was thinner than those in Groups II and III (p = 0.004 and p = 0.002, respectively). A single method is inadequate for establishing early and / or mild visual impairment in MS. The authors conclude that there is no gold standard strategy for diagnosing and monitoring visual involvement in MS from an ophthalmological standpoint. All approaches, including novel functional techniques and structural analysis, should be used more frequently by neuro-ophthalmologists to aid in unravelling the enigma of axonal degradation in MS. FDTP should be considered in addition to SAP for assessing subclinical visual system involvement.