scholarly journals Sex, blinking, and dry eye

2020 ◽  
Vol 123 (2) ◽  
pp. 831-842
Author(s):  
Ashley Culoso ◽  
Cynthia Lowe ◽  
Craig Evinger

Blinking sustains the corneal tear film generated by sexually dimorphic lacrimal and meibomian glands. Our study examines whether trigeminal control of blinking is also sexually dimorphic by investigating trigeminal reflex blinking, associative blink modification, and spontaneous blinking in male and female rats before and after unilateral dry eye caused by exorbital gland removal. Before gland removal, female rats exhibited a lower threshold for evoking trigeminal reflex blinks, a weaker effect of associative blink modification, and longer-duration spontaneous blinks than males. Spontaneous blink rate, reflex blink excitability, and occurrence of blink oscillations did not differ between the sexes. Reanalysis of previous data showed that humans showed the same blink sexual dimorphisms as rats. During the first 2 wk of dry eye, trigeminal blink circuit excitability and blink oscillations steadily rose in male rats, whereas excitability and blink oscillations did not change in females. Following dry eye, spontaneous blink duration increased for both males and females, whereas spontaneous blink rate remained constant for males but decreased for females. The associative modification treatment to depress trigeminal blink amplitude initially produced blink depression in males that converted to blink potentiation as trigeminal excitability rose, whereas females exhibited progressively more blink depression. These data indicated that dry eye increased excitability in male trigeminal reflex blink circuits at the expense of circuit modifiability, whereas trigeminal modifiability increased in females. This increased modifiability of female trigeminal blink circuits with dry eye may contribute to the preponderance of females developing the focal dystonia, benign essential blepharospasm. NEW & NOTEWORTHY All the elements controlling the corneal tear film are sexually dimorphic. Blinking, which smooths and maintains the tear film, also exhibits sex differences. Dry eye increases the sexual dimorphisms of blinking, including increased exaggeration of excitability in males and enhanced modifiability of the female trigeminal complex. This increased modifiability may explain female predominance in the development of the focal dystonia, benign essential blepharospasm.

2021 ◽  
Author(s):  
Madlen Merten ◽  
Johannes F.W. Greiner ◽  
Tarek Niemann ◽  
Meike Grosse Venhaus ◽  
Daniel Kronenberg ◽  
...  

Female sex is increasingly associated to a loss of bone mass during aging and an increased risk for fractures developing nonunion. Hormonal factors and cell-intrinsic mechanisms are suggested to drive these sexual dimorphisms, although underlying molecular mechanisms are still a matter of debate. Here, we observed a decreased capacity of calvarial bone recovery in female rats and a profound sexually dimorphic osteogenic differentiation human adult neural crest-derived stem cells (NCSCs). Next to an elevated expression of pro-osteogenic regulators, global trancriptomics revealed Lysine Demethylase 5D (KDM5D) to be highly upregulated in differentiating male NCSCs. Loss of function by siRNA or pharmacological inhibition of KDM5D significantly reduced the osteogenic differentiation capacity of male NCSCs. In summary, we demonstrate craniofacial osteogenic differentiation to be sexually dimorphic with the expression of KDM5D as a prerequisite for accelerated male osteogenic differentiation, emphasizing the analysis of sex-specific differences as a crucial parameter for treating bone defects.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xueyi Zhou ◽  
Yang Shen ◽  
Jianmin Shang ◽  
Xingtao Zhou

Abstract Background To assess the effects of warm compress (WC) on tear film lipid layer, blink pattern and Meibomian gland function in patients with dry eye following femtosecond laser small incision lenticule extraction (SMILE) and laser-assisted subepithelial keratomileusis (LASEK). Methods We enrolled 37 eyes of 37 participants, each with dry eye for more than 2 years following SMILE (25 eyes) or LASEK (12 eyes). WC was performed using a spontaneously heating eye mask. Tear film break-up time (TBUT), tear film lipid layer thickness (TFLLT), blink pattern, Meibomian secretory function scores (MGS), visual acuity, spherical equivalent (SE), keratometry, central corneal thickness (CCT) and aberration were assessed before and after WC. Results After WC, the following mean values all increased relative to baselines: CCT, SE, minimum (Min-), maximum (Max-) and average (Ave-) TFLLT, TBUT, total MGS (TMGS), number of glands secreting any liquid (MGL), and complete blink rate (CBR) (p values ranging from < 0.001 to 0.042). Partial blink frequency (PBF) and partial blink rate (PBR) decreased (p = 0.002 in both cases). The decrease of PBF was higher in SMILE subgroup than in LASEK (p = 0.030). TBUT variation was positively correlated with that of Ave-TFLLT and TMGS (p = 0.046, 0.028, respectively). Max-TFLLT variation was correlated with that of TMGS (p = 0.020). Conclusions WC may temporarily increase tear film thickness and stability, decrease partial blink, and partly augment Meibomian gland function in dry eye patients after corneal refractive surgeries. Future studies are required to investigate long term clinical efficacy and safety.


2021 ◽  
Author(s):  
Xueyi Zhou ◽  
Yang Shen ◽  
Jianmin Shang ◽  
Xingtao Zhou

Abstract Background To assess the effects of warm compress (WC) on tear film lipid layer, blink pattern and Meibomian gland function in patients with dry eye following femtosecond laser small incision lenticule extraction (SMILE) and laser-assisted subepithelial keratomileusis (LASEK). Methods We enrolled 37 eyes of 37 participants, each with dry eye for more than 2 years following SMILE (25 eyes) or LASEK (12 eyes). WC was performed using a spontaneously heating eye mask. Safety parameters and effectiveness parameters (tear film break-up time, TBUT; tear film lipid layer thickness, TFLLT; blink pattern, and Meibomian secretory function scores, MGS) were assessed before and after WC. Results After WC, the following mean values all increased relative to baselines: central corneal thickness, spherical equivalent, minimum (Min-), maximum (Max-) and average (Ave-) TFLLT, TBUT, total MGS (TMGS), number of glands secreting any liquid (MGL), and complete blink rate (CBR) (p values ranging from < 0.0001 to 0.042). Partial blink frequency (PBF) and partial blink rate (PBR) decreased (p = 0.002 in both cases). The decrease of PBF was higher in SMILE subgroup than in LASEK (p = 0.030). TBUT variation was positively correlated with that of Ave-TFLLT and TMGS (p = 0.046, 0.028, respectively). Max-TFLLT variation was correlated with that of TMGS (p = 0.020). Conclusions WC may temporarily improve tear film quality and blink pattern, augment Meibomian gland function, and relieve dry eye symptoms after corneal refractive surgery, particularly that using the SMILE technique.


2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Chao Sun ◽  
Xiaofan Chen ◽  
Yanming Huang ◽  
Huan Zou ◽  
Wei Fan ◽  
...  

Abstract Background To study the effects of aerobic exercise (AE) on tear secretion and tear film stability in dry eye patients. Methods This study consisted of two parts, each part included 3 groups, namely dry eye without AE group, dry eye with AE group and pre-clinical dry eye with AE group. In part 1, we studied the variations of Schirmer I test and six tear compositions before and after AE (34 eyes in each group). In part 2, we studied the variations of tear meniscus height, first and average non-invasive tear breakup time (F-NITBUT and A-NITBUT), lipid layer thickness, number of incomplete and complete blinks, partial blink rate (PBR) and visual acuity before and after AE (30 eyes in each group). Results In dry eye with AE group, Schirmer I test at 0 min after AE increased significantly compared to baseline (P < 0.001), the oxidative stress marker 8-hydroxy-2′-deoxyguanosine after AE decreased significantly compared to baseline (P = 0.035, P = 0.045), F-NITBUT and A-NITBUT after AE prolonged significantly compared to baseline (P < 0.001, P = 0.007, P = 0.036; P < 0.001, P = 0.001, P = 0.044), number of incomplete blinks and PBR at 10 min after AE decreased significantly compared to baseline (P < 0.001; P < 0.001) while number of complete blinks increased significantly (P < 0.001). Besides, significant differences were also found between dry eye with AE group and dry eye without AE group at all above corresponding time point (P < 0.05). Conclusion AE promotes tear secretion and improves tear film stability in dry eye patients. AE may be a potential treatment for dry eye. Trial registration Chinese Clinical Trial Registry, ChiCTR2000038673. Registered 27 September 2020,


1997 ◽  
Vol 77 (5) ◽  
pp. 2842-2846 ◽  
Author(s):  
Edward J. Schicatano ◽  
Michele A. Basso ◽  
Craig Evinger

Schicatano, Edward J., Michele A. Basso, and Craig Evinger. Animal model explains the origins of the cranial dystonia benign essential blepharospasm. J. Neurophysiol. 77: 2842–2846, 1997. The current study demonstrates that combining two mild alterations to the rat trigeminal reflex blink system reproduces the symptoms of benign essential blepharospasm, a cranial dystonia characterized by uncontrollable spasms of blinking. The first modification, a small striatal dopamine depletion, reduces the tonic inhibition of trigeminal reflex blink circuits. The second alteration, a slight weakening of the lid-closing orbicularis oculi muscle, begins an adaptive increase in the drive on trigeminal sensory-motor blink circuits that initiates blepharospasm. By themselves, neither of these modifications causes spasms of lid closure, but combined, they induce bilateral forceful blinking and spasms of lid closure. A two-factor model based on these rodent experiments may explain the development of benign essential blepharospasm in humans. The first factor, a subclinical loss of striatal dopamine, creates a permissive environment within the trigeminal blink circuits. The second factor, an external ophthalmic insult, precipitates benign essential blepharospasm. This two-factor model may also be applicable to the genesis of other cranial dystonias.


2022 ◽  
Vol 8 ◽  
Author(s):  
Lei Tian ◽  
Ya Wen ◽  
Siyuan Li ◽  
Peng Zhang ◽  
Yinghui Wang ◽  
...  

Objectives: To evaluate the effect of astaxanthin in the treatment of mild-to-moderate dry eye disease (DED) in middle-aged and elderly patients.Methods: 120 eyes of 60 middle-aged and elderly patients with mild-to-moderate DED were enrolled in this prospective, one-group, quasi-experimental study. Six milligram Astaxanthin tablets (Weihong Haematococcus Pluvialis Astaxanthin, Hangzhou Xinwei Low Carbon Technology R&amp;D Co., Ltd., China) were administered orally, twice daily for 30 ± 2 days. History of eye diseases, treatment, systemic disease, and medication before the test were recorded. In addition, the ocular surface disease index (OSDI) questionnaire, non-invasive tear break-up time (NIBUT), fluorescein break-up time (FBUT), corneal fluorescein staining (CFS) score, eyelid margin signs, meibomian gland (MG) expressibility, meibum quality, meibomian gland dropout (MGDR), Schirmer I test (SIt), tear meniscus height (TMH), bulbar conjunctiva congestion degree, blink frequency, incomplete blink rate, and thickness of tear film lipid layer were collected before treatment, 2 weeks after the initiation of treatment, and at the end of treatment. Visual acuity (VA), intraocular pressure (IOP), anterior segment, fundus, discomfort symptoms and other adverse reactions were also monitored throughout the study to assess the safety.Results: OSDI score, NIBUT, BUT, CFS score, eyelid margin signs, MG expressibility, meibum quality, and blink frequency improved significantly to varying degrees after treatment compared with those before the treatment (P &lt; 0.05), while TMH, SIt, conjunctival congestion, the thickness of tear film lipid layer, MGDR, incomplete blink rate, VA and IOP did not differ (P &gt; 0.05).Conclusions: Oral administration of astaxanthin improves the symptoms and signs of middle-aged and elderly patients with mild-to-moderate DED.


Author(s):  
Hemalatha S. ◽  
Rati S.

Dry eye syndrome is a common condition that results from reduced tear production or excessive tear evaporation or an abnormality in the production of mucus or lipids normally found in the tear layer or combination of these. If blinking is decreased or if the eyelids cannot be closed, they may dry out leading to dry eye. It is accompanied by increased osmolarity of the tear film and inflammation on the surface of the eye may occur of left untreated leading to pain, ulcers or scars on the cornea and loss of vision. Prevalence of dry eye range from 5% to 35% worldwide while in India it is 29.25%. Tear substitute are the only treatment modality with modern medicine, only providing symptomatic relief. Ayurveda describes similar condition called Sushkakshi Paka and this patient was treated with Tarpana and Nasya with Jeevantyadi Ghrita.


2021 ◽  
Vol 22 (1) ◽  
pp. 422
Author(s):  
Ming-Tse Kuo ◽  
Po-Chiung Fang ◽  
Shu-Fang Kuo ◽  
Alexander Chen ◽  
Yu-Ting Huang

Most studies about dry eye disease (DED) chose unilateral eye for investigation and drew conclusions based on monocular results, whereas most studies involving tear proteomics were based on the results of pooling tears from a group of DED patients. Patients with DED were consecutively enrolled for binocular clinical tests, tear biochemical markers of DED, and tear proteome. We found that bilateral eyes of DED patients may have similar but different ocular surface performance and tear proteome. Most ocular surface homeostatic markers and tear biomarkers were not significantly different in the bilateral eyes of DED subjects, and most clinical parameters and tear biomarkers were correlated significantly between bilateral eyes. However, discrepant binocular presentation in the markers of ocular surface homeostasis and the associations with tear proteins suggested that one eye’s performance cannot represent that of the other eye or both eyes. Therefore, in studies for elucidating tear film homeostasis of DED, we may lose some important messages hidden in the fellow eye if we collected clinical and proteomic data only from a unilateral eye. For mechanistic studies, it is recommended that researchers collect tear samples from the eye with more severe DED under sensitive criteria for identifying the more severe eye and evaluating the tear biochemical and proteomic markers with binocular concordance drawn in prior binocular studies.


1997 ◽  
Vol 273 (3) ◽  
pp. R1126-R1131 ◽  
Author(s):  
Y. X. Wang ◽  
J. T. Crofton ◽  
S. L. Bealer ◽  
L. Share

The greater pressor response to vasopressin in male than in nonestrous female rats results from a greater increase in total peripheral resistance in males. The present study was performed to identify the vascular beds that contribute to this difference. Mean arterial blood pressure (MABP) and changes in blood flow in the mesenteric and renal arteries and terminal aorta were measured in conscious male and nonestrous female rats 3 h after surgery. Graded intravenous infusions of vasopressin induced greater increases in MABP and mesenteric vascular resistance and a greater decrease in mesenteric blood flow in males. Vasopressin also increased renal vascular resistance to a greater extent in males. Because renal blood flow remained unchanged, this difference may be due to autoregulation. The vasopressin-induced reduction in blood flow and increased resistance in the hindquarters were moderate and did not differ between sexes. Thus the greater vasoconstrictor response to vasopressin in the mesenteric vascular bed of male than nonestrous females contributed importantly to the sexually dimorphic pressor response to vasopressin in these experiments.


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