Evaluation of Accommodation Amplitude and Convergence Insufficiency in Patients with Multiple Sclerosis

To evaluate the near reflex components, including accommodation, convergence, and binocular fusional vergences in patients with multiple sclerosis (MS).

MS patients under 35 years of age without visual evoked potential (VEP) abnormalities (MS Group) and age-matched healthy individuals of (Control Group) were included in the study. Fusional vergence amplitudes, the amplitude of accommodation (AA), stereopsis measurements, near-object fixation and near point of convergence (NPC) measurements, Convergence Insufficiency Symptoms Survey (CISS) results, and the presence of nystagmus were recorded retrospectively from the files of the cases. Statistical comparison was made between the groups.

The mean age was 28.04 ± 3.7 years in the MS group (20 females, 4 males) and 27.16 ± 3.1 years in the control group (20 females, 5 males) (p = .763). There was no statistically significant difference between groups in stereopsis (p = .395), mean convergence (p = .666), and divergence amplitudes (p = .773) at a distance, and mean convergence and (p = .836) divergence amplitudes (p = .877) at near, and NPC measurements (p = .908). The mean AA was 5.31 ± 0.7 D in the MS group and 6.1 ± 0.8 D in the control group (p < .001). CISS results were lower in the control group (p < .001). In addition, gaze-evoked nystagmus was statistically significantly higher in the MS group (p < .001).

Compared to the healthy control group, MS patients under 35 who did not have optic neuritis had lower accommodation amplitude and more signs in favor of convergence insufficiency symptoms. In addition, gaze evoked nystagmus was observed at a higher rate in the MS group. These findings may guide us in understanding the asthenopia findings of MS patients without optic neuritis.