Stereoacuity testing discloses abnormalities in multiple sclerosis without optic neuritis

Binocular Vision in Patients with Multiple Sclerosis

PURPOSE

Oculomotor disorders have been reported in multiple sclerosis (MS) in up to 80% of cases. There have been studies evaluating binocular vision in several neurological diseases, but not in MS. Considering that a high percentage of eye-movement anomalies have been reported, the aim of this study was to analyze binocular vision in these subjects.

METHODS

A total of 59 participants with MS - 21 with monocular optic neuritis, eleven with binocular optic neuritis, and 27 without optic neuritis - and 26 age-matched controls were enrolled. Binocular vision was analyzed using near point of convergence (NPC), positive and negative fusional vergence for far and near distance, measurement of heterophoria at both distances with cover and modified Thorington tests, and random-dot stereoscopy.

RESULTS

The percentage of subjects with abnormal NPC values was highest in the MS group, followed by the MSONm (MS with optic neuritis in one eye), MSONb (MS with optic neuritis in both eyes), and control groups. MS patients showed an esophoric trend at near distance. Positive fusional vergence showed no significant differences between control and MS groups, but higher variability in recovery was found in MS groups. Negative fusional vergence at near distance showed significant differences between the control group and the two MS groups, with optic neuritis for both break-point and recovery values. A high percentage of patients with MS had alterations on stereopsis.

CONCLUSION

Alterations in binocular vision were present in MS, with divergence at near distance and stereopsis the most affected parameters. Likewise, MS patients with optic neuritis showed worse binocular vision.

Binocular, Accommodative and Oculomotor Alterations In Multiple Sclerosis: A Review

Multiple sclerosis (MS) is an acquired demyelinating and inflammatory neurodegenerative disease affecting the central nervous system (CNS). Clinical and subclinical ocular disturbances occur in almost all patients with MS. The objective of this narrative review was to collect and summarize the available scientific information on oculomotor, accommodative and binocular alterations that have been reported in MS. A systematic search strategy with the following descriptors was carried out: multiple sclerosis, ocular motility disorders, internuclear ophthalmoplegia, nystagmus, vergences, fixation, pupil reflex, accommodation and stereopsis. According to the search, some oculomotor alterations were found to be commonly reported in MS, such as alterations in saccades and nystagmus. In contrast, accommodative, vergence and stereopsis alterations have not been comprehensively studied despite their relevance, with only minimal evidence showing a potential negative impact of the disease on these aspects. In conclusion, oculomotor impairment is a common component of disability in MS patients and should be considered when managing this type of patients. More research is still needed to know the real impact of this disease on binocular vision and accommodation.

Stereopsis in Early Diabetic Retinopathy

PURPOSE

The present study was undertaken to compare the stereoacuities measured by TNO and Titmus tests, in diabetic patients with early retinopathies and those without diabetes (control group).

METHODS

In this study, 139 participants (43 with diabetes mellitus, and 96 age-matched controls) were recruited from a retina subspecialist clinic in Qazvin, Iran, from September 2016 to March 2017. The stereo-acuities were measured following subjective refraction by Titmus and TNO tests at 40 cm. The patients with diabetes whose retinal exam revealed no background retinopathy or only microaneurysms (very mild diabetic retinopathy) in the worse eye were enrolled into this study.

RESULTS

In the diabetic group, with TNO, the stereoacuity levels in 95.3% of the subjects were in 120, 240, and 480 levels, while in the non-diabetic group, 86.4% of the subjects were in 30, 60, and 120 levels. In the diabetic group, with Titmus, 86.1% of the subjects were in 40, 50, and 60 levels, while in the nondiabetic group 91.7% of the subjects were in 40 levels. The correlation between TNO and Titmus was statistically significant (r = 0.338, P<0.001) for the non-diabetic group, while it was not statistically significant (r = -0.034, P= 0.827) for the diabetic group.

CONCLUSION

In the early stages of diabetic retinopathy, the global pathway of stereopsis is damaged more than the local. The difference in severity of damage to local and global pathways in patients with diabetes indicates that there may be different underlying mechanisms for these two pathways.

Longitudinal time-domain optic coherence study of retinal nerve fiber layer in IFNβ-treated and untreated multiple sclerosis patients

Quantification of the retinal nerve fiber layer (RNFL) by optical coherence tomography (OCT) has been proposed to provide an indirect measure for retinal axonal loss. The aim of the present study was to determine whether interferon beta (IFNβ) treatment impedes retinal axonal loss in multiple sclerosis (MS) patients. A total of 48 patients with MS (24 IFNβ-1b-treated and 24 untreated subjects) and 12 healthy controls were enrolled in a prospective longitudinal OCT study. OCT measurements were performed for both eyes of each subject at baseline, and at 3-, 6-, and 12-month follow-up examinations using a time-domain OCT. At each visit, we additionally recorded full-field visual evoked potential (VEP) responses and performed the paced auditory serial addition test (PASAT), in addition to expanded disability status scale (EDSS) scoring. Generalized estimation equation (GEE) was used to account for repeated measurements and paired-data. The model-based approach predicted a monthly reduction in the RNFL thickness by 0.19 µm in the eyes of the MS subjects. The reduction was estimated to be 0.17 µm in case of IFNβ-treatment and 0.16 µm in case of no treatment. Treatment duration and group allocation were not significantly associated with the RNFL thickness. Inclusion of further longitudinal data (EDSS, two and three second PASAT) in each of our models did not result in any significant association. In summary, over a period of one year no significant association between IFNβ-1b treatment and RNFL thinning was identified in patients with MS.

Optical coherence tomography in multiple sclerosis and neuromyelitis optica: an update

Optical coherence tomography (OCT) uses light interference patterns to produce a cross-sectional image of the retina. It is capable of measuring the unmyelinated axons of the retinal ganglionar cells as they converge on the optic disc. In a disease like multiple sclerosis (MS), in which axonal loss has been identified as an important cause of sustained disability, it may prove an invaluable tool. OCT has demonstrated that axonal loss occurs after each episode of optic neuritis and that the degree of axonal loss is correlated to visual outcomes. Furthermore, axonal loss occurs in MS even in the absence of inflammatory episodes, and the degree of this loss is correlated with the duration of the disease process, with more thinning as the disease advances and in progressive forms. Thus, OCT retinal nerve fiber layer measurements may represent an objective outcome measure with which to evaluate the effect of treatment.