Purpose: To describe the efficacy of MP-1 in detecting early multiple sclerosis (MS) retinal lesions and in monitoring the effectiveness of treatment in terms of changes in macular sensitivity.
Methods: A 21-year-old woman with MS was referred to us complaining of recurrent episodes of eyesight loss in both eyes. At ophthalmologic examination, best-corrected visual acuity was 20/25 bilaterally; ophthalmoscopy showed bilateral slight optic neuritis without swelling of the disc. Static perimetry of central visual field (30 degrees, by Octopus 101, Haag-Streit AG, Switzerland) and retinal sensitivity of the 12 central degrees (by MP-1 Micro Perimeter, Nidek Inc., Italy) were performed on the patient at that time. The micro perimeter (MP-1) showed a loss of sensitivity in the macular region with 0.28+/-0.9 dB sensitivity in the right eye and 19.42+/1.5 dB in the left. The mean fixation stability was 91% considering 2 degrees and 99% considering 4 degrees around the fixation points in the right eye, and 97% in 2 degrees and 100% in 4 degrees central degrees in the left. In the weeks that followed vision continued to get worse in both eyes, so she underwent a steroid therapy with methylprednisolone IV 1000 mg/day for 5 days and 500 mg/day for 3 days.
Results: After 8 days of therapy the MP-1 showed a significant recovery in the right eye, with mean light sensitivity being 19.61+/-1.3 dB in the right eye and 20.0+/-0 dB in the left eye in both macular and peripapillary regions. The mean fixation stability was 100% considering 2 degrees and 100% considering 4 degrees around the fixation points in both eyes.
Conclusions: The MP-1 can be an interesting tool for neuro-ophthalmologists as it allows a more precise evaluation of the macular and peripapillary region, which is not easily studied with conventional automated perimetry. In MS, the presence of a subclinical form of optic nerve involvement can be demonstrated in a very early stage, and well followed by the introduction of micro perimeter testing in the standard examination protocol.