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Melatonin is a ubiquitous molecule and widely distributed in nature, with functional activity occurring in unicellular organisms, plants, fungi, and animals. Several studies have indicated that melatonin synthesis occurs in the retina of most vertebrates, including mammals. The retinal biosynthesis of melatonin and the mechanisms involved in the regulation of this process have been extensively studied. Circadian clocks located in the photoreceptors and retinal neurons regulate melatonin synthesis in the eye. Photoreceptors, dopaminergic amacrine neurons, and horizontal cells of the retina, corneal epithelium, stroma endothelium, and the sclera all have melatonin receptors, indicating a widespread ocular function for melatonin. In addition, melatonin is an effective antioxidant which scavenges free radicals and up-regulates several antioxidant enzymes. It also has a strong antiapoptotic signaling function, an effect that it exerts even during ischemia. Melatonin cytoprotective properties may have practical implications in the treatment of ocular diseases, like glaucoma and age-related macular degeneration.

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Purpose:This study sought to identify the magnitude and the possible risk factors of ocular complications in patients with Obstructive Sleep Apnea (OSA).Methods:A hospital-based cross-sectional study with a nested case-control design was conducted. Qualifying study subjects were patients who had been diagnosed with moderate to severe OSA (AHI index of ≥ 5, n=80), and control subjects (n=20) who had an AHI index of ≤ 5 (“normal”). Study participants were recruited from Mansoura University Hospital’s Sleep Disorders Clinic in Mansoura, Egypt.Selected subjects were assessed for ocular complications at Mansoura Univerity Hospital Ophthalmic Center, (Mansoura), Egypt. An ophthalmic history was recorded, and opthalmic testing was carried out. The testing included unaided visual acuity measurement, refraction, best-corrected visual acuity measurement, slit lamp bio-microscopic evaluation of the anterior segment and anterior segment photography, dilated fundus examination, intraocular pressure measurement, fundus photo, and fluorescein angiography, and visual field assessment. Various tests of OSA symptoms were also monitored, including the AHI, lowest oxygen concentrations and desaturation index plus the overall severity index. .Results:It was found that OSA patients n=28 (35%), n=24 (30%), n=4 (5%) had senile cataract, normal tension glaucoma, and retinal ischemia, respectively, with an overall prevalence of 45%. Additionally, the OSA group had seven times greater risk (OR=7.36, 95%CI: 1.6-33.86) of vision-threatening disorders compared to the controls. OSA patients were observed to be at a greater risk of senile cataract 28 (35%), normal tension glaucoma 24 (30%), retinal ischemia 4 (5%) and conjunctival hyperemia and dry eye (OR=3.77, 95%CI: 1.02-13.95, OR=4.36, 95%CI: 1.26-17.08). Also, multivariate logistic regression analysis testing showed that the lowest oxygen saturation index was the only significant predictor negatively associated with vision-threatening disorders (OR=0.84, 95%CI: 0.75-0.93).Conclusion:The risk of vision-threatening and non-threatening ocular disorders is higher among OSA cases. The lowest oxygen saturation index was the only significant predictor of vision-threatening disorders. These findings support the recommendation that a full ophthalmic examination should be carried out on patients with confirmed OSA.

To evaluate both refractive and biometry results of presbyopic refractive lens exchange (RLE) with trifocal intraocular lens (IOL) implantation in eyes previously submitted to corneal laser vision correction (LVC).

Purpose To compare the refractive predictability of ray tracing IOL calculations based on OCT data versus traditional IOL calculation formulas based on reflectometry in patients with a history of previous myopic laser vision correction (LVC). Patients and Methods This was a prospective interventional single-arm study of IOL calculations for cataract and refractive lens exchange (RLE) patients with a history of myopic LVC. Preoperative biometric data were collected using an optical low coherence reflectometry (OLCR) device (Haag-Streit Lenstar 900) and two optical coherence tomography (OCT) devices (Tomey Casia SS-1000 and Heidelberg Engineering Anterion). Traditional post LVC formulas (Barret True-K no-history and Haigis-L) with reflectometry data, and ray tracing IOL calculation software (OKULIX, Panopsis GmbH, Mainz, Germany) with OCT data were used to calculate IOL power. Follow-up examination was 2 to 3 months after surgery. The main outcome measure, refractive prediction error (RPE), was calculated as the achieved postoperative refraction minus the predicted refraction. Results We found that the best ray tracing combination (Anterion-OKULIX) resulted in an arithmetic prediction error statistically significantly lower than that achieved with the best formula calculation (Barret True-K no-history) (−0.13 D and −0.32 D, respectively, adjusted p = 0.01), while the Barret TK NH had the lowest SD. The absolute prediction error was 0.26 D and 0.35 D for Anterion-OKULIX and Barret TK NH, respectively, but this was not statistically significantly different. The Anterion-OKULIX calculation also had the highest percentage of eyes within ± 0.25, compared to both formulas and within ±0.50 and ±0.75 compared to the Haigis-L ( p = 0.03). Conclusion Ray tracing calculation based on OCT data from the Anterion device can yield similar or better results than traditional post LVC formulas. Ray tracing calculations are based on individual measurements and do not rely on the ocular history of the patient and are therefore applicable for any patient, also without previous refractive surgery.

Aim: To investigate the effect of negative inspiratory effort, as generated by the Mueller manoeuvre, on intraocular pressure (IOP) and pulsatile ocular blood flow (POBF) in healthy young adults. Methods: Seven volunteers with no history of systemic or ocular disease were recruited (mean age 30.7 years, range 25-40 years, M/F: 4/3). After initial instruction and practice of the Mueller manoeuvre, baseline measurements of IOP and POBF were obtained for both eyes after 10 and 15 minutes of rest, respectively, in the supine position. Thereafter, the Mueller manoeuvre was performed creating a mouthpiece pressure of 220 cm H 2 O, for at least 15 seconds followed by a 5 minute rest. The manoeuvre was repeated with a mouthpiece pressure of 240 cm H 2 O. IOP and POBF were measured 5-15 seconds into the manoeuvre for both 220 cm H 2 O (M2A) and 240 cm H 2 O (M4A) and directly upon recovery (after two respiratory cycles) from each manoeuvre (M2B, M4B). Baseline measurements were compared using paired t test, whereas manoeuvre induced changes in IOP and POBF were analysed individually using repeated measures ANOVA with Student-Newman Keuls post hoc analyses. Linear regression analysis was used to investigate a dose-response effect. Results: No significant differences were found between baseline measurements so they were subsequently pooled. There was a significant decrease in IOP for M2B (29.2%, p,0.05), M4A (213.8%, p,0.05), and M4B (215.6%, p,0.05), relative to baseline. A dose-response relation was found for the effect of mouthpiece pressure on measurements 5-10 seconds into the manoeuvre (M2A and M4A, r = 0.54, p = 0.045). There was a trend of increased POBF relative to baseline for all measurements; however, significance was reached for M4B only (p = 0.039). Conclusion: It was shown that forced inspiratory efforts as generated by the Mueller manoeuvre are associated with a dose dependent decrease in IOP and a concomitant increase in pulsatile ocular blood flow. R espiratory fluctuations in the intraocular pressure (IOP) are a well known phenomenon that is caused by blood pressure (BP) related volume changes in the vascular beds of the eye.1 During spontaneous breathing there is a sinusoidal variation in blood pressure that can be attributed to the mechanical effect of pleural pressure swings on the venous return to the heart. 2 However, during greater respiratory efforts, such as deep breathing and forced inspiratory or expiratory manoeuvres, the BP response is also influenced by several autonomic cardiovascular reflexes such as cardiopulmonary reflexes, pulmonary reflexes, and arterial reflexes. Obstructive sleep apnoea (OSA) is a complex disorder characterised by upper airway collapses during sleep and by the persistence of inspiratory effort during the interruptions of airflow.4 5 Whereas the term apnoea refers to total obstruction of airflow, the clinical definition of OSA includes both total and partial airway obstructions (hypopnoea) lasting for 10 seconds or more. Polysomnographic evidence for OSA (>10 episodes...

Background Strabismus is a complex disease that has various treatment approaches each with its own advantages and drawbacks. In this context, shared decisions making (SDM) is a communication process with the provider sharing all the relevant treatment alternatives, all the benefits, and risks of each procedure, while the patient shares all the preferences and values regarding his/her choices. In that way, SDM is a bidirectional process that goes beyond the typical informed consent. Therefore, it is known a little of the extent to which SDM influences the satisfaction with the treatment outcome along with strabismus patients. To study this correlation, an SDM-Q-9 questionnaire was provided within surgical consultations where treatment decisions were made; the SDM-Q-9 aims to assess the relationship between the post-operative patient’s satisfaction and their SMD score. Methods The study is considered a prospective observational pilot study. Eligible patients were adult patients diagnosed with strabismus, who had multiple treatment options, were given at the right of choice without being driven into a physician’s preference. Ninety-three strabismus patients were asked to fill out the SDM-Q-9 questionnaire related to their perception of SDM during the entire period of strabismus treatment. After the treatment, patients were asked to rate their satisfaction level with the surgical outcome as excellent, good, fair, and poor. Descriptive statistics and the linear regression statistical tests (Spearman, Mann Whitney U, and Kriskal–Wallis) were used as analysis tools. Results The average age of the participants was 24, where 50.6% were women. The mean SDM-Q-9 score among patients was 32 (IQR = 3). The postoperative patient satisfaction was rated as being excellent by 16 (17.2%) patients, good by 38 (40.9%), fair by 32 (34.4%), and poor by 7 patients (7.5%). Data analysis by linear regression statistical tests showed a positive correlation between the SDM-Q-9 score and the patient satisfaction related to the surgery outcome (B = 0.005, p < 0.001). Criteria in assessing patients’ satisfaction were age, gender, and strabismus type. A positive correlation between SDM and real satisfaction (r = 0.834, p < 0.01) was found with age, and no significant relationship was found while taking into consideration the responder’s gender and the strabismus type. Conclusions Assessing patient satisfaction after choosing a treatment for strabismus method helped us evaluate the gaps in constructive dialogue that would lead to a positive outcome for both patient and clinician. The correlation between the SDM process and the patients’ satisfaction with surgery outcome, adjusted by age, has been established. These findings can serve as a springboard to further communicative improvements related to the SDM process and between patients and physicians, thereby consequently leading to patients’ satisfaction raise in strabismus care. The study underlines the importance of further analysis and validation of on-ground interactions among the adolescent and adult patients and the clinicians across the strabismus management trajectory. A multicentral study and its validation will follow.