ASMR as Idiosyncratic Experience: Experimental Evidence

The Autonomous Sensory Meridian Response (ASMR) is a tingling sensation across the scalp that occur in response to specific triggering audio and visual stimuli, connected with the Default Mode Network. Our study (N = 76) aimed to test the neurophysiology of ASMR by examining pupil diameter and brain activity. Assuming the idiosyncratic nature of ASMR, we expected results detecting opposite physiological outcomes considering pupil diameter and brain activation. We used a battery of self-reports to investigate psychological dimensions; for the physiological measures, we used two instruments: PupilCore and NeuroSky MindWave Mobile 2. The results showed an augmented pupillary diameter during the ASMR video, regardless of the perception of tingles. On the other hand, the arousal level during the ASMR video was lower than the other conditions. The difference between the two neurophysiological measures appeared as peculiar and can be considered as the promoting phenomenon for ASMR psychological outcomes.

Pupillary diameter in brain death or clinical death: is it reliable?

Dilated pupils are traditionally considered one of the main signs of clinical death and brain death. Although in clinical practice even in biological death pupil size often remains medium. Pupil size evaluation is not included into modern CPR protocols and brain death diagnostics protocols.

Intracameral anesthetic mydriatic (ICAM) assisted pediatric cataract surgery

Purpose: To assess the efficacy and safety of intracameral mydriatic and anesthetic combination for pupillary dilation in pediatric cataract surgery Methods: This prospective series included children <12 years, with visually significant unilateral or bilateral cataracts planned for cataract surgery with/without intraocular lens implantation. At the beginning of surgery, 0.025 ml of a combination of phenylephrine hydrochloride (0.31%), tropicamide (0.02%), and lidocaine hydrochloride (1%) was injected intracamerally. The efficacy of the combination was tested by achieving capsulorhexis and intraocular lens implantation without additional mydriatics. Results: We recruited 13 patients (16 eyes) with a mean age of 4.1 ± 3.9 years. The mean pupillary diameter changed increased from 1.92 to 5.68 mm after injection of one unit (0.025 ml) of drug ( p < 0.0001). There was a strong positive correlation of the pupillary dilation with axial length ( R = 0.86) and horizontal corneal diameter ( R = 0.81). Seventy-five percent patients had a pupillary diameter >6 mm and surgery could be completed successfully in all cases without additional mydriatics. In all cases, pupil dilated as the surgery progressed. No adverse event to the drug was noted. Conclusions: Intracameral mydriatic-anesthetic combination is an effective and safe way to obtain stable mydriasis in pediatric cataract surgery.

Changes in Anterior Chamber Angle and Pupillary Diameter after Implantation of a New Posterior Chamber Phakic Intraocular Lens

Purpose: To evaluate the effect of the Eyecryl posterior chamber phakic intraocular lens (pIOL) on iridocorneal angle (ICA) parameters, anterior chamber depth (ACD), and pupillary size.Methods: The medical files of myopic patients who had implantation of the Eyecryl posterior chamber pIOL were reviewed retrospectively. Trabecular-iris space area at 500 and 750μm (TISA500, TISA750), angle opening distances at 500 and 750μm (AOD500, AOD750), anterior chamber depth (ACD), iridocorneal angle (ICA), and pupil diameter under different illumination conditions were analyzed preoperatively, and at 1 and 3 months postoperatively.Results: Ninety-three eyes of 48 patients were included in the study. The mean age of patients was 31.63 ±4.95 years (range, 21-54). The mean ICA decreased from 49.97° ± 6.33 before surgery to 30.75° ± 5.86 and 30.79° ± 5.74 at 1 and 3 months after surgery, respectively. The mean ACD was reduced from 3.23 ± 0.22 mm before surgery to 2.55 ± 0.34 mm and 2.46 ± 0.28 mm at 1 and 3 months after surgery, respectively. TISA500, TISA750, AOD500, and AOD750 were also reduced significantly after surgery. The mean pupil size under photopic, mesopic and scotopic illuminations decreased insignificantly by 1 month and continued to decrease significantly by 3 months after surgery.Conclusion: The implantation of the Eyecryl posterior chamber pIOL in myopic patients caused significant changes in anterior chamber parameters including ICA, ACD, TISA 500, TISA 750, AOD 500, AOD 750, and the pupil diameter under different illumination conditions.

The Role of Back Optic Zone Diameter in Myopia Control with Orthokeratology Lenses

We compared the efficacy of controlling the annual increase in axial length (AL) in myopic Caucasian children based on two parameters: the back optic zone diameter (BOZD) of the orthokeratology (OK) lens and plus power ring diameter (PPRD) or mid-peripheral annular ring of corneal steepening. Data from 71 myopic patients (mean age, 13.34 ± 1.38 years; range, 10–15 years; 64% male) corrected with different BOZD OK lenses (DRL, Precilens) were collected retrospectively from a Spanish optometric clinic. The sample was divided into groups with BOZDs above or below 5.00 mm and the induced PPRD above or below 4.5 mm, and the relation to AL and refractive progression at 12 months was analyzed. Three subgroups were analyzed, i.e., plus power ring (PPR) inside, outside, or matching the pupil. The mean baseline myopia was −3.11 ± 1.46 D and the AL 24.65 ± 0.88 mm. Significant (p < 0.001) differences were found after 12 months of treatment in the refractive error and AL for the BOZD and PPRD. AL changes in subjects with smaller BOZDs decreased significantly regarding larger diameters (0.09 ± 0.12 and 0.15 ± 0.11 mm, respectively); in subjects with a horizontal sector of PPRD falling inside the pupil, the AL increased less (p = 0.035) than matching or outside the pupil groups by 0.04 ± 0.10 mm, 0.10 ± 0.11 mm, and 0.17 ± 0.12 mm, respectively. This means a 76% lesser AL growth or 0.13 mm/year in absolute reduction. OK corneal parameters can be modified by changing the OK lens designs, which affects myopia progression and AL elongation. Smaller BOZD induces a reduced PPRDs that slows AL elongation better than standard OK lenses. Further investigations should elucidate the effect of pupillary diameter, PPRD, and power change on myopia control.

Duration of Mydriasis Produced by 0.5% and 1% Tropicamide in Sprague–Dawley Rats

Ophthalmic examination (OE) is a common part of preclinical studies. Pupillary dilation to facilitate OE may affect results of other planned testing. The purpose of this study was to determine the duration of mydriasis produced by commercially available 0.5% and 1% tropicamide in ophthalmologically normal albino rats. Twelve female Sprague–Dawley rats were used. A single drop of 1% tropicamide was applied to one eye of each rat. A single drop of balanced salt solution (BSS) was applied to the contralateral eye. Measurements of pupillary diameter (PD) were obtained using a digital caliper at 0, 20, 40, 60, 120, 180, 240, 300, and 360 min after application. After a 3-wk washout period, the procedure was repeated using 0.5% tropicamide. Pupillary dilation sufficient to allow posterior segment evaluation was achieved with 0.5% and 1% tropicamide. Maximum PD after treatment with 0.5% tropicamide was 4.17 ± 0.22 mm at 40 min; maximum PD after treatment with 1% tropicamide was not significantly different (4.28 mm at both 20 and 40 min (± 0.43 mm and 0.23 mm, respectively)). Mean PD remained above 3.5 mm in treated eyes for 60 min. In eyes treated with 0.5% tropicamide, mean PD was significantly different from baseline mean PD for that eye up to 300 min. In eyes treated with 1% tropicamide, mean PD was significantly different thanbaseline mean PD for that eye at all timepoints. Both concentrations of tropicamide produced a transient mild to moderate mydriasis in the contralateral eye. Duration of action is at least 5 h for 0.5% tropicamide and 6 h for 1% tropicamide. Results of this study support use of 0.5% tropicamide for OE in albino rats, with administration performed no more than 60 min prior to examination.

Difference in Pupillary Diameter as an Important Factor for Evaluating Amplitude of Accommodation: A Prospective Observational Study

Presbyopia is increasing globally due to aging and the widespread use of visual display terminals. Presbyopia is a decrease in the eye’s amplitude of accommodation (AA) due to loss of crystalline lens elasticity. AA differs widely among individuals. We aimed to determine the factors that cause presbyopia, other than advanced age, for early medical intervention. We examined 95 eyes of 95 healthy volunteers (33 men, 62 women) aged 22–62 years (mean: 37.22 ± 9.77 years) with a corrected visual acuity of ≥1.0 and without other eye afflictions except ametropia. Subjective refraction, AA, maximum and minimum pupillary diameters during accommodation, axial length of the eye, and crystalline lens thickness were measured. AA was measured using an auto refractometer/keratometer/tonometer/pachymeter. The difference between maximum and minimum pupillary diameters was calculated. On multiple regression analysis, age and difference in pupillary diameter were both significantly and independently associated with AA in participants aged <44 years, but not in those aged ≥45 years. Our results suggest that the difference in pupillary diameter could be an important age-independent factor for evaluating AA in healthy individuals without cataract. Thus, improving the difference in pupillary diameter values could be an early treatment target for presbyopia.