Abstract
Purpose :
To investigate the relationship between afferent and efferent pathways in blinking reflex in patients diagnosed of benign essential blepharospasm (BEB).
Methods :
A prospective observational unicentric controlled cohort study was performed. Eyes of patients with BEB treated with botulinum toxin (BT) that are followed in Ophthalmology and Neurology department of a tertiary referral hospital who accepted to participate were included. For a same patient both eyes could be included. A complete ophthalmological examination was performed. Demographic data was collected. Ophthalmological collected variables were: duration of the disease, time to BT treatment from diagnosis, Jankovic scale, BEB disability index, ocular comorbidities, Ocular Surface Disease Index (OSDI), visual acuity, Oxford grading system, tear break-up time, Schirmer’s test, conjunctivochalasis, lid ptosis examination, corneal sensitivity (Cochet-Bonnet esthesiometer), meibomian gland disfunction (MGD) (Keratograph®, Oculus, Wetzlar, Germany), corneal topography (HR Pentacam® (Oculus, Wetzlar, Germany)), corneal nerve plexus parameters (nerve fiber density (NFD), nerve branch density (NBD), nerve fiber length (NFL), nerve fiber tortuosity (NFT) (corneal confocal microscopy (HRL II/RCM (Heidelberg Engineering GmbH, Dossenheim, Germany))).
Results :
A total of 28 eyes were included in the study, 15 from study patients and 13 from controls. OSDI (%) was 20.22±11 in BEB eyes vs 4.64±6.5 in non-BEB eyes (p-value 0.001). Corneal Esthesiometry was 4.03±1.56 vs 5.76 cm, (p-value 0.026). Schirmer test was 9.62±8.2vs 13±9.2 mm (p-value 0.261). MGD grading was 2 cm or more in 31% (4) BEB eyes vs 23% (3) in non-BEB eyes (p-value 0.65). BUT test 4.9 (±1.3) vs 11 (±5.6) seconds mean (p-value <0.001). Oxford classification was 2 or more in 11 (84%) BEB eyes vs 3 (23%) in non-BEB eyes. NFD was 2.6±0.73 in BEB eyes vs 4.07±0.86 main nerves/frame in non-BEB eyes (p-value 0.001); NBD 3.13±1.45 vs 3.38±1.26 (p-value 0.58) main branches/frame, NFL 582.00 ± 262.40 vs 779.27±109.59 total length/frame(p-value 0.033) (Fig1).
Conclusions :
The results obtained from this study suggest there may be a relationship between dry eye severity and anatomical corneal nerve changes and BEB. Though, causative relationship could not be established due to study design. Further investigation should be necessary in order to learn about the physiopathology of BEB.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.