OBJECTIVE: To compare, between Alzheimer\'s disease (AD) patients and healthy individuals, corneal subbasal nerve plexus (CSNP) parameters and corneal sensitivities.
METHODS: Twenty-two patients who were followed up with Alzheimer\'s disease (Alzheimer\'s group) and 18 age- and gender-matched healthy individuals (control group) were included in this cross-sectional study. CSNP parameters, including nerve fiber length (NFL), nerve fiber density (NFD), and nerve branch density (NBD), were evaluated using in vivo confocal microscopy. Corneal sensitivity was evaluated using a Cochet-Bonnet esthesiometer. The results were compared between the two groups.
RESULTS: In the Alzheimer\'s group, NFL was 12.2 (2.4) mm/mm2, NFD was 12.5 [3.1] fibers/mm2, and NBD was 29.7 [9.37] branches/mm2. In the control group, NFL was 16.5 (2.0) mm/mm2, NFD was 25.0 [3.13] fibers/mm2, and NBD was 37.5 [10.9] branches/mm2. All three parameters were significantly lower in the Alzheimer\'s group compared to the control group (p < 0.001, p < 0.001, and p = 0.001, respectively). Similarly, corneal sensitivity was significantly lower in the Alzheimer\'s group (55.0 [5.0] mm) compared to the control group (60.0 [5.0] mm) (p < 0.001).
CONCLUSIONS: We determined that, in AD, corneal sensitivity decreases significantly, in parallel with the decrease in corneal nerves. Changes in the corneal nerve plexus and a decrease in corneal sensitivity may be used in the early diagnosis and follow-up of AD. In addition, ocular surface problems secondary to these changes should also be kept in mind.

BACKGROUND: Corneal sensitivity can decrease by several ocular conditions, such as dry eye or refractive surgery, which favor ocular epithelial lesions and is measured using an esthesiometer. The study\'s primary objective was to demonstrate the efficacy and safety of the non-contact esthesiometer BRILL, which delivers air pulses to the corneal surface to assess corneal sensitivity.
METHODS: A single-center, prospective, controlled pilot study was carried out in adult patients with healthy eyes and or with pathology. Corneal sensitivity measurements were made in triplicate for both eyes at three consecutive visits. The esthesiometer BRILL was used in all visits, and on the last visit, the contact esthesiometer Cochet-Bonnet was also used. The results of both devices were compared by transforming them into force values.
RESULTS: 54 subjects with a mean age of 50.43 (SD 16.55, interval 18-87), 77.78% women, were included. Comparing the forces applied by both esthesiometers in the healthy eyes, in the eyes with pathology in all the groups, and in the dry eyes showed significant differences, p = 0.03603, p = 0.00614, and p = 0.0001, respectively.
CONCLUSIONS: The BRILL esthesiometer proved to be an effective and safe tool for non-contact assessment of corneal sensitivity with operator-independent repeatability. The measurements had a good agreement and comparable range with the Cochet-Bonet aesthesiometer measurements in healthy and dry eyes but with no interchangeable values. This portable device can help ophthalmologists and optometrists to diagnose eye pathologies that cause decreased corneal sensitivity and to assess the efficacy of therapy and disease progression.

UNASSIGNED: We measure changes in ocular surface sensation after pterygium surgery with a conjunctival autograft.
UNASSIGNED: This prospective, interventional study was carried out in patients, with nasal primary pterygium undergoing pterygium surgery with conjunctival autograft. Sensation was measured by applying the tip of the Cochet-Bonnet esthesiometer filament perpendicular to the ocular surface in the cornea and conjunctiva. Patients were tested preoperatively (baseline), and at 2 weeks, 2 and 4 months, postoperatively.
UNASSIGNED: Nineteen eyes of 18 patients completed the 4-month follow-up. Mean age was 61±10.1 (range 36-76) years. Corneal sensation returned to normal values in all at 2 and at 4 months. The central cornea was significantly more sensitive compared to the average of the four peripheral measurements pre- (59.2 mm vs 48.3 mm, p=0.000) and postoperatively (59.2 mm vs 48.4 mm, p=0.000). Conjunctival sensation was reduced significantly 2 months postoperatively in the inferior region (p=0.04). Four months postoperatively, it was more sensitive in the superior area (13.9 mm vs 17.1 mm, p=0.01) and the inferior area (13.7 mm vs 19.5 mm, p=0.003). In each matching area, the cornea was significantly more sensitive than the conjunctiva pre- and postoperatively (p=0.00). Sensation was not significantly different between the sexes or age groups.
UNASSIGNED: This study demonstrates the presence of inferior and superior conjunctival hyperesthesia at conjunctival autograft sites after pterygium surgery. The healing process, sensory input, tear film instability and epitheliopathy of the ocular surface are possible explanations for these novel findings.

UNASSIGNED: This study aims to measure the two-point discrimination (TPD) values of the upper extremities of healthy young Turkish individuals.
UNASSIGNED: Between March 2016 and June 2016, a total of 60 healthy students (31 males, 29 females; mean age: 22.0±1.7 years; range, 19 to 27 years) were included. Eleven grand upper limb parts which take innervation from the brachial plexus were measured with an esthesiometer.
UNASSIGNED: The values at the dominant sides were statistically significantly greater than the non-dominant sides at those areas: upper lateral arm (p=0.001), lower lateral arm (p=0.001), mid-posterior arm (p=0.001), mid-lateral forearm (p=0.001), mid-posterior forearm (p=0.012), skin over the first dorsal interossei muscle (p=0.031), and palmar surface of distal phalanx of the thumb (p=0.045). Both dominant and non-dominant lower lateral arm TPD measurement results increased in males compared to females, indicating a statistically significant difference (p=0.005 and p=0.011, respectively). Also, dominant and non-dominant mid-posterior arm measurement scores were found to statistically significantly increase in males compared to females (p=0.019 and p=0.040, respectively).
UNASSIGNED: Our study results show that laterality, with lower values on the non-dominant side, but not the sex, has an effect on TPD. The findings of this study may be useful in establishing the normative data for TPD in the upper extremity parts of healthy young Turkish individuals.

UNASSIGNED: The discovery of an accommodative response to ocular surface stimulation could inform clinicians and patients that optical effects may occur due to ocular discomfort and perhaps an assessment of the accommodative system after carrying out interventions impacting the ocular surface, may be warranted.
UNASSIGNED: There have been no previous reports evaluating the effect of noxious stimulation on accommodation. Here, the accommodative response of healthy participants after the application of noxious corneal stimulation is characterised.
UNASSIGNED: A computerised Belmonte pneumatic esthesiometer was used to determine detection thresholds (using ascending method of limits), and to randomly deliver mechanical and chemical stimuli from levels of detection threshold to twice the threshold in 50% steps, to the central cornea of 15 healthy subjects. For each suprathreshold stimulus, accommodative and pupil responses were measured with a validated eccentric infrared photorefractor. Quantitative differences in accommodative/pupil response, stimulus modality/intensity and left/right eye were analysed using repeated measures ANOVA. Tukey HSD tests were used for all post hoc analyses.
UNASSIGNED: Accommodation increased from baseline as the corneal apical stimulus intensity increased. This happened regardless of whether mechanical or chemical stimulation occurred (ANOVA, p < 0.05). At 200% threshold, accommodative response was greater than all stimulus intensities (Tukey HSD, all p < 0.05). There was no difference in pupil response between the stimulation intensities (100%, 150% and 200% threshold). There was no difference in accommodative response between the left and right eye for mechanical (ANOVA, p > 0.05) and chemical stimulation (ANOVA, p > 0.05).
UNASSIGNED: Noxious stimulation of the cornea seems to produce a dose-dependent increase in the accommodative response in the eyes but not a dose-dependent pupil response.

BACKGROUND: Hypochromatic macules with altered sensitivity are the first manifestations of skin leprosy. Validation of this sensory loss assists in the confirmation of the clinical diagnosis.
OBJECTIVE: The aim of the study was to quantify the loss of sensation in leprosy lesions using the Semmes-Weinstein monofilament to strengthen the clinical diagnosis mainly of macular forms.
METHODS: Seventy-four hypochromatic macules in the macular leprosy subgroup, 27 typical borderline leprosy subgroup lesions and 49 macules of other macular dermatoses (non-leprosy group) were evaluated using the 0.05 g force Semmes-Weinstein monofilament to quantify the alteration of sensitivity within and outside of the lesions. The esthesiometric change index was established as the total number of points with altered sensation divided by the total number of tested points within the lesions to calculate the internal esthesiometric change index and outside the lesions to calculate the peripheral esthesiometric change index; these indexes were calculated for all groups. The difference (Δ) between the esthesiometric change indices of the lesional area and the adjacent skin was calculated for the leprosy and nonleprosy groups.
RESULTS: The percentage of points with touch sensitivity alterations within the macular and typical borderline leprosy lesions was higher in leprosy than in the non-leprosy group. The borderline and macular leprosy presented higher esthesiometric change index within injured areas than outside injured areas or in the nonleprosy group (P < 0.005). When internal esthesiometric change index values in the macular and borderline leprosy groups were higher than 0.53 and 0.5, respectively, the receiver operating characteristic curve showed 98% sensitivity and approximately 99% specificity for both groups (P < 0.0001). Regarding the difference between indices, borderline and macular leprosy had values that were higher and closer to one than in the nonleprosy group (P < 0.0001), with 100% sensitivity and 96.5% specificity for leprosy diagnosis when ΔLG was higher than 0.34. A limitation was the inability to perform a double-blind study.
CONCLUSIONS: Semmes-Weinstein esthesiometry is a simple, useful and low-cost tool to quantify the focal alteration of cutaneous sensitivity to improve clinical leprosy diagnosis, especially for macular lesions.

OBJECTIVE: To determine the efficacy of a single treatment of topical and subconjunctival 0.1% preservative-free morphine sulfate (PFMS) in providing analgesia following phacoemulsification in dogs.
METHODS: Ten diabetic and ten non-diabetic client-owned dogs treated with bilateral phacoemulsification.
METHODS: A prospective, randomized, masked, negative-controlled clinical trial was performed. All dogs received topical (0.2 mL) and subconjunctival (0.1 mL) 0.1% PFMS in one eye following phacoemulsification. The other eye received an equal volume and mode of administration of balanced salt solution (BSS). Ophthalmic examination, blinking rates, tearing, conjunctival hyperemia, aqueous flare, and central corneal esthesiometry (CCE) were evaluated in all eyes 1 day prior to surgery and at 4, 24, and 48 hours after surgery. Complete physical examination, ocular ultrasound, electroretinogram, hemogram, and serum biochemistry panel were performed in all dogs prior to phacoemulsification. All dogs received the standard of care treatment before and after surgery, including uniform anesthetic protocol.
RESULTS: Baseline ophthalmic exams were unremarkable, except for the presence of cataracts, in all dogs. The mean CCE (±SD) at 4 hours post-operatively was 1.76 ± 1.27 g/mm2 and 1.85 ± 1.5 g/mm2 for the negative control and PFMS groups, respectively. There were no statistical differences in blepharospasm, conjunctival hyperemia, tearing, aqueous flare, blinking rates, CCE, or intraocular pressure (IOP) between the treatment groups for any of the time points for the non-diabetic and diabetic dogs, or for all dogs combined (P > .05).
CONCLUSIONS: Topical and subconjunctival 0.1% PFMS did not affect the evaluated parameters after phacoemulsification in the study dogs at the timepoints assessed.

OBJECTIVE: To evaluate whether topical ocular application of 1% morphine sulfate would change corneal sensitivity and to identify the duration of action.
METHODS: Eight healthy adult horses.
METHODS: Corneal touch threshold (CTT) was measured in the center of one randomly selected eye of each horse by Cochet-Bonnet esthesiometer (Luneau Cochet-Bonnet Esthesiometer; Western Ophthalmics, Lynnwood, WA, USA). Immediately following baseline CTT measurement, 0.3 ml of 1.0% preservative-free morphine sulfate (Morphine Sulfate 25 mg/ml Preservative-free; Hospira, Lake Forest, IL, USA) (3 mg) was applied to the tested eye. The same volume of artificial tear (LiquiTears; Major Pharmacauticals, Livonia, MI, USA) solution was then applied to the control eye following acquisition of baseline CTT. Corneal touch threshold was then subsequently measured at 1 min after medication application, followed by every 5 min until 60 min post administration. If the corneal touch threshold had not returned to baseline by 60 min, measurements were continued at 15-min intervals until corneal sensitivity returned to baseline CTT measurement up to 180 min post administration if needed. The control eye was treated identically and measurements on the control eye stopped when the corresponding treated eye returned to baseline.
RESULTS: Mean baseline CTT of both eyes was 21.8 mm with an identical range of 15-30 mm. Mean corneal touch threshold was not statistically different between morphine-treated and control eyes (P = 0.22). There was a large degree of inter- and intrasubject variation in the CTT measurements obtained. All but three horses were considered to be at baseline values by 60 min.
CONCLUSIONS: Topical ophthalmic 1% morphine sulfate did not have a clinically significant analgesic effect on the corneal touch threshold of intact healthy equine corneas.

BACKGROUND: Laryngo-pharyngeal mechano-sensitivity (LPMS) is involved in dysphagia, sleep apnea, stroke, irritable larynx syndrome and cough hypersensitivity syndrome among other disorders. These conditions are associated with a wide range of airway reflex abnormalities. However, the current device for exploring LPMS is limited because it assesses only the laryngeal adductor reflex during fiber-optic endoscopic evaluations of swallowing and requires a high degree of expertise to obtain reliable results, introducing intrinsic expert variability and subjectivity.
METHODS: We designed, developed and validated a new air-pulse laryngo-pharyngeal endoscopic esthesiometer with a built-in laser range-finder (LPEER) based on the evaluation and control of air-pulse variability determinants and on intrinsic observer variability and subjectivity determinants of the distance, angle and site of stimulus impact. The LPEER was designed to be capable of delivering precise and accurate stimuli with a wide range of intensities that can explore most laryngo-pharyngeal reflexes.
RESULTS: We initially explored the potential factors affecting the reliability of LPMS tests and included these factors in a multiple linear regression model. The following factors significantly affected the precision and accuracy of the test (P < 0.001): the tube conducting the air-pulses, the supply pressure of the system, the duration of the air-pulses, and the distance and angle between the end of the tube conducting the air-pulses and the site of impact. To control all of these factors, an LPEER consisting of an air-pulse generator and an endoscopic laser range-finder was designed and manufactured. We assessed the precision and accuracy of the LPEER\'s stimulus and range-finder according to the coefficient of variation (CV) and by looking at the differences between the measured properties and the desired values, and we performed a pilot validation on ten human subjects. The air-pulses and range-finder exhibited good precision and accuracy (CV < 0.06), with differences between the desired and measured properties at <3 % and a range-finder measurement error of <1 mm. The tests in patients demonstrated obtainable and reproducible thresholds for the laryngeal adductor, cough and gag reflexes.
CONCLUSIONS: The new LPEER was capable of delivering precise and accurate stimuli for exploring laryngo-pharyngeal reflexes.

Here, we reconsider the status quo in testing mechanical sensitivity with von Frey\'s hairs. The aim is to improve paw withdrawal estimates by integrating current psychometric theory, and to maximise the clinical relevance and statistical power of mechanosensory models. A wealth of research into human tactile stimulus perception may be extended to the quantification of laboratory animal behaviour. We start by reviewing each step of the test, from its design and application through to data analysis. Filament range is assessed as a whole; possible test designs are compared; techniques of filament application to mice and rats are considered; curve fitting software is introduced; possibilities for data pooling and curve fitting are evaluated. A rational update of classical methods in line with recent advances in psychometrics and supported by open source software is expected to improve data homogeneity, and Reduce and Refine animal use in accord with the \'3R\' principles.