Cochet-Bonnet Esthesiometer Research Articles

The Relation of Ocular Surface Irregularity and Visual Disturbance in Early Stage Acanthamoeba Keratitis.

To evaluate the relation between ocular surface irregularity and visual disturbance in early stage Acanthamoeba keratitis (AK). Fifteen patients with culture-proven AK underwent routine ophthalmic examinations, including best-corrected visual acuity (BCVA) measurement, slitlamp biomicroscope examination, and corneal fluorescein dye staining test, in both the eyes. We also evaluated the corneal sensitivity with Cochet-Bonnet esthesiometer, tear functions by Schirmer's test, and ocular surface irregularity by corneal topography and compared the results with the contralateral healthy eyes in this study. The mean logarithm of the minimum angle of resolution BCVA (0.71±0.77) was significantly lower in the eyes with AK (P=0.002). Epithelial disorders were present in all eyes, and radial keratoneuritis in 14 eyes (93.3%). The mean corneal sensitivity (39.3±24.1 mm) was significantly lower in eyes with AK compared with the healthy eyes (P=0.005). The mean Schirmer's test value (22.5±12.0 mm) in eyes with AK was significantly higher compared with the healthy eyes (P=0.01). The ocular surface irregularity indices (the surface regularity index, 2.47±0.42; the surface asymmetry index, 3.24±1.31) were significantly higher in eyes with AK compared with contralateral healthy eyes (P<0.0001 and P<0.0001, respectively). The ocular surface disease in AK is associated with decrease in corneal sensitivity and increase in Schirmer's test value and ocular surface irregularity indices. The visual disturbance in AK may owe not only to corneal haze but also to ocular surface irregularity.

Baseline Corneal Sensitivity and Duration of Action of Proparacaine in Rehabilitated Juvenile Kemp's Ridley Sea Turtles (Lepidochelys kempii)

Abstract Corneal sensitivity and the duration of action of a topical anesthetic drop, proparacaine, were evaluated prospectively. Baseline corneal touch threshold (CTT) was determined using a Cochet-Bonnet esthesiometer in 25 healthy, rehabilitated Kemp's ridley sea turtles (Lepidochelys kempii). Corneal touch threshold was defined as the filament length required to elicit a blink in at least three out of five applications. The onset and duration of action of proparacaine was determined in nine of the Kemp's ridley sea turtles. One drop of proparacaine was applied to each eye and the CTT was subsequently measured at 1, 5, 15, 30, and 45 min. Results demonstrated that the mean CTT for the Kemp's ridley sea turtles was 5.7 cm, with a median of 6 cm. Additionally, proparacaine had an onset of action within 1 min after application (17/18 eyes). The duration of action of proparacaine exceeded the 45 min time limit in all eyes. This study shows that Kemp's ridley sea turtles have an exceptionally sensitive corn...

Conjunctiva Limbal Autograft with Fibrin Glue for Capillary Hemangioma

To present reversal of sensation of conjunctival limbal autograft. A 48-year-old female presented with red-colored mass in the left eye involving the temporal bulbar conjunctiva and limbus. It was vascular, elevated, compressible and immobile. Excisional biopsy, and conjunctiva limbal autgrafting with fibrin glue was performed, and histopathologic examination confirmed the di agnosis of capillary hemangioma of conjunctiva. Sensation of conjunctival autograft was measured at each month with CochetBonnet esthesiometer for six months. Sensation of conjunctival autograft was none at first month and reached to normal level at fourth month. Conjunctiva limbal autograft with fibrin glue obtained good cosmesis for management of capillary hemangioma. Conjunctival autograft had no sensation at first month. Its sensation gradually increased and returned to normal level after 4 month.

Fluctuations of Corneal Sensitivity in Dry Eye Syndromes--A Longitudinal Pilot Study.

The aim of this study was to observe corneal sensitivity (CoS) longitudinally in patients with dry eye and to evaluate the correlation between CoS, severity, and the etiology of dry eye syndrome (DES). In this prospective study, 46 patients with DES were examined on 4 occasions within 3 months. CoS was measured by the Cochet-Bonnet esthesiometer. Tear films were evaluated for lipid layer thickness, breakup time, fluorescein and lissamine green staining, and Schirmer test. Patients were classified into etiologic subgroups: hormonal, immunologic, toxic, neural, and environmental. For statistical statistics, Mann-Whitney and Kruskal-Wallis tests were used. Serial data curves of CoS demonstrated pronounced variability of values. CoS and SICCA scores were negatively correlated (r = -0.454, P = 0.007). The Schirmer test and CoS were positively correlated (r = 0.363, P = 0.013). The environmental group had the highest CoS values (5.5). There was no significant difference in CoS neither between nerve-induced and nonnerve-induced DES groups (P = 0.858) nor within the subgroups (P = 0.118). During 3 months, CoS increased in all patients (4.8-5.1). The DES severity was negatively correlated with CoS, indicating a reduction of neural function in severe DES. Our results showed diminished CoS in severe dry eye although there was a high variability of CoS. This supports the hypothesis of different states of compensation as the disease continues and an association of CoS with different causes of dry eye. However, no statistical differences were found between etiological subgroups.

Corneal and conjunctival sensitivity in rosacea patients

PurposeTo assess corneal and conjunctival sensitivity in rosacea patients. MethodsA total of 55 patients with rosacea and 37 control subjects participated in the study. Corneal and conjunctival sensitivity was determined by Cochet-Bonnet esthesiometer. Subjective symptoms of ocular dryness were evaluated using Ocular Surface Disease Index (OSDI). Schirmer’s I test (ST), tear breakup time (tBUT) and ocular surface staining with fluorescein were carried out to measure objective signs. ResultsThe mean corneal and conjunctival sensitivity did not differ significantly between rosacea patients and controls (all p>0.05). Schirmer’s I test and tBUT were significantly reduced (p=0.004 for OD and p<0.001 for OS) and grade of ocular surface staining was significantly high (p=0.018 for OD and p=0.038 for OS) in rosacea patients. Corneal and conjunctival sensitivity did not show significant correlation with ST, tBUT, ocular surface staining (Oxford Schema), duration of rosacea and OSDI score. ConclusionsCorneal and conjunctival sensitivity did not change significantly in rosacea.

Conjunctival and corneal sensitivity in patients under topical antiglaucoma treatment.

The purpose of the study is to measure corneal and conjunctival sensitivity in patients under glaucoma topical treatment as compared to a control group. It is a case-control study. Corneal and conjunctival esthesiometry were carried out through a Cochet-Bonnet esthesiometer. We took healthy individuals as controls, who did not use any type of ophthalmic topical medications and without history of ocular surface pathology or irritation. The study group was subdivided per number of applications (1,2, and 3 or more applications). From a total 182 eyes from 91 patients, of which 26 (28.57%) were controls and 65 (71.43%) were in the study group, a mean corneal sensitivity of 58.98±2.25mm was found in the control group and 52.97±6.41mm in patients using topical medication. Mean conjunctival sensitivity was 18.80±5.40mm in the control group and 11.76±5.45mm in the study group. There was no statistically significant difference among groups when separated by 1, 2, and 3 or more applications. Eyes under use of timolol-containing medications showed lower sensitivity values as compared to other topical antiglaucoma medications. Corneal and conjunctival sensitivities are diminished in patients with chronic use of topical hypotensive medications and these results can explain the lack of correlation between signs and symptoms that is typically found in patients treated for glaucoma or ocular hypertension.

Corneal sensitivity after small-incision lenticule extraction and laser in situ keratomileusis

To longitudinally evaluate corneal sensitivity after small-incision lenticule extraction and compare the results with those in previous studies. London Vision Clinic, London, United Kingdom. Retrospective case series. Consecutive myopic eyes treated with small-incision lenticule extraction using the Visumax femtosecond laser were studied. Corneal sensitivity was measured centrally and at 4 paracentral locations using a Cochet-Bonnet esthesiometer preoperatively and 1 day, 1 week, and 1, 3, 6, and 12 months postoperatively. Results were compared with averaged results from previous laser in situ keratomileusis (LASIK) and small-incision lenticule extraction studies. The mean spherical equivalent was -6.85 diopters (D) ± 2.57 (SD). The mean age was 36 ± 11 years. After small-incision lenticule extraction, the preoperative mean central corneal sensitivity dropped from 54 mm preoperatively to 33 mm 1 day postoperatively, rising to 40 mm, 45 mm, 48 mm, 54 mm, and 55 mm over 12 months; it reached baseline at 6 months (P > .05). For 21 LASIK studies, the mean central corneal sensitivity dropped from 56 mm preoperatively to 6 mm at 1 day, rising to 14 mm, 23 mm, 34 mm, 45 mm, and 51 mm over 12 months. For 8 small-incision lenticule extraction studies, central corneal sensitivity dropped from 57 mm preoperatively to 39 mm at 1 week, then rose to 39 mm, 42 mm, 49 mm, 52 mm, and 54 mm over 12 months; it was higher than after LASIK at 1 week and 1, 3, and 6 months (P < .05). Recovery of central corneal sensitivity to baseline was reached by 6 months after small-incision lenticule extraction and was higher than after LASIK for the first 6 months after surgery. Dr. Reinstein is a consultant to Carl Zeiss Meditec AG, has a proprietary interest in the Artemis technology (Arcscan, Inc.), and is an author of patents related to very high-frequency digital ultrasound administered by the Center for Technology Licensing at Cornell University, Ithaca, New York, USA. No other author has a financial or proprietary interest in any material or method mentioned.

Corneal Anesthesia With Site 1 Sodium Channel Blockers and Dexmedetomidine.

Amino-amide or amino-ester local anesthetics, which are currently used for topical ocular anesthesia, are short acting and may delay corneal healing with long-term use. In contrast, site 1 sodium channel blockers (S1SCBs) are potent local anesthetics with minimal adverse tissue reaction. In this study, we examined topical local anesthesia with two S1SCBs, tetrodotoxin (TTX) or saxitoxin (STX) individually or in combination with α2-adrenergic receptor agonists (dexmedetomidine or clonidine), and compared them with the amino-ester ocular anesthetic proparacaine. The effect of test solutions on corneal healing was also studied. Solutions of TTX ± dexmedetomidine, TTX ± clonidine, STX ± dexmedetomidine, dexmedetomidine, or proparacaine were applied to the rat cornea. Tactile sensitivity was measured by recording the blink response to probing of the cornea with a Cochet-Bonnet esthesiometer. The duration of corneal anesthesia was calculated. Cytotoxicity from anesthetic solutions was measured in vitro. The effect on corneal healing was measured in vivo after corneal debridement followed by repeated drug administration. Addition of dexmedetomidine to TTX or STX significantly prolonged corneal anesthesia beyond that of either drug alone, whereas clonidine did not. Tetrodotoxin or STX coadministered with dexmedetomidine resulted in two to three times longer corneal anesthesia than did proparacaine. S1SCB-dexmedetomidine formulations were not cytotoxic. Corneal healing was not delayed significantly by any of the test solutions. Coadministration of S1SCBs with dexmedetomidine provided prolonged corneal anesthesia without delaying corneal wound healing. Such formulations may be useful for the management of acute surgical and nonsurgical corneal pain.

The Utility of an Artificial Substitute to Improve Corneal Sensitivity in Glaucomatous Patients on Chronic Therapy with Prostaglandin Analogs

To evaluate whether a tear substitute can improve corneal subepithelial nerve plexus and corneal sensitivity in glaucomatous patients. This study was prospective, longitudinal, and single arm. Twenty glaucomatous patients were recruited. All the patients were treated with a prostaglandin analog with preservative for at least 1 year. Preservative-free artificial tears (0.5% tamarind seed polysaccharide 0.5(®) eye drops single-dose preservative free [Oftagen]) were prescribed thrice per day. The participants were subjected to clinical and instrumental evaluation at baseline (T0), after 1 month (T1) and after 3 months (T3) of treatment. All patients were examined with a digital corneal confocal laser-scanning microscope (HRT II Rostock Cornea Module; Heidelberg Engineering GmbH) and Cochet-Bonnet corneal esthesiometer. After the artificial substitute, corneal and conjunctival sensitivity significantly (P < 0.001) improved at T1 and T3 compared to the baseline. A significant correlation was found between break-up time and both central corneal sensitivity and the number of fibers. The use of a preservative-free artificial substitute in association with a topical therapy with chronic preservative could increase the compliance of patients.

Topical NSAIDs effect on corneal sensitivity.

Topical nonsteroidal antiinflammatory drugs (NSAIDs) are administered topically for a variety of ophthalmologic conditions. Brand diclofenac and brand ketorolac were previously shown to have topical anesthetic effects in addition to analgesic effects. Using the same method, we measured similar anesthetic effects of the 4 currently available topical NSAIDs--generic diclofenac, generic ketorolac, brand bromfenac, and brand nepafenac. Baseline corneal sensitivity was measured on 10 healthy adult volunteers with a Cochet-Bonnet esthesiometer. One drop of the agent being studied was applied to the right eye every 5 minutes for a total of 4 drops. Corneal sensitivity was measured immediately after the last topical application and every 15 minutes for 60 minutes. After a 1-week washout period, a different agent was studied until all 4 NSAIDs were evaluated. Corneal sensitivity profiles over time were similar for all NSAIDs. Corneal sensitivity decreased significantly from baseline immediately after topical application remaining flat from 0 to 30 minutes and then rising from 45 to 60 minutes back toward baseline in all treatment groups (P < 0.001). The maximal absolute drop in corneal sensitivity as measured by pressure thresholds was greatest for diclofenac [28.6 mm (95% confidence intervals {CI}, 19.8-37.4)], followed by ketorolac [21.1 mm (95% CI, 15.1-27.1)], bromfenac [16.9 mm (10.7-23.1)], and nepafenac [16.4 mm (95% CI, 12.7-20.1)]. Only diclofenac and nepafenac were statistically different in maximal decrease in sensitivity. All 4 currently available NSAIDs demonstrated anesthetic effects similar to brand diclofenac and brand ketorolac.

Poly(ADP-Ribose) Polymerase Inhibition Improves Corneal Epithelial Innervation and Wound Healing in Diabetic Rats.

We evaluated the effect of poly(ADP-ribose) polymerase (PARP) inhibition by using 1,5-isoquinolinediol (ISO) on corneal epithelial innervation in diabetic rats. ISO (3 mg/kg, intraperitoneal) or vehicle was administered to rats with diabetes induced by streptozotocin for 4 weeks. Epithelial innervation, epithelial wound healing, and corneal sensation were evaluated in diabetic rats (DM rats), diabetic rats treated with ISO (DM-ISO rats), and nondiabetic (non-DM) rats. The density of epithelial innervation was calculated separately as nerve terminals and sub-basal nerve plexus by analyzing the images of whole-mount corneas. Healed areas of epithelial defect were measured at 0, 18, and 36 hours after creating a 4-mm wound on the cornea. Corneal sensitivity test was conducted using a Cochet-Bonnet handheld esthesiometer. Additionally, PARP1 and poly(ADP-ribosyl)ated polymers (pADPr) as its products, were identified in trigeminal ganglions (TGs) by Western blot analysis and immunofluorescence staining. In DM rats, the density of nerve terminals (5.57% ± 0.94%) and sub-basal nerve plexus (22.08 ± 1.78 mm/mm(2)) was significantly reduced in comparison with that in DM-ISO rats (8.64% ± 1.42%, 30.82 ± 2.01 mm/mm(2), respectively) and non-DM rats (9.02 ± 1.14%, 34.77 ± 4.45 mm/mm(2), respectively). The percentages of healed area of the epithelial defects at 18 and 36 hours were significantly smaller in DM rats (23.8 ± 5.2%, 53.2 ± 4.6%, respectively) than in DM-ISO rats (43.2 ± 1.4%, 75.8 ± 2.2%, respectively) and non-DM rats (48.1 ± 8.6%, 86.1 ± 3.3%, respectively). Corneal sensitivity decreased in DM rats (51.1 ± 0.3 mm) but not in DM-ISO rats (57.8 ± 0.2 mm). There were no differences between parameters in DM-ISO rats and those in non-DM rats. Diabetic corneas showed loss of epithelial innervation, resulting in delayed epithelial healing and decreased corneal sensitivity. Inhibition of poly(ADP-ribose) polymerase (PARP) with 1,5-isoquinolinediol alleviated these diabetes-induced alterations in the corneal epithelium in the diabetic rats.

Ocular surface sensitivity repeatability with Cochet-Bonnet esthesiometer.

To determine the repeatability of ocular surface threshold measurements using the Cochet-Bonnet esthesiometer on the same day and 3 months apart. Two separate studies were conducted to determine the repeatability of ocular surface threshold measurements made on the same day (n = 20 subjects) and 3 months apart (n = 29 subjects). The Cochet-Bonnet esthesiometer was used to measure corneal and inferior conjunctival thresholds using the ascending method of limits. The pressure exerted by the Cochet-Bonnet esthesiometer was determined using an analytical balance, for both the 0.08- and 0.12-mm-diameter filaments. This calibration was then used to convert filament length measurements to pressure. Repeatability was determined using a Bland and Altman analysis. The pressure exerted at each filament length differed between the two filament diameters. The measured pressure also differed from values provided by the manufacturer. Repeatability of threshold measurements at the central cornea was shown to be good, with better repeatability for same-day measurements (coefficient of repeatability [CoR] = ±0.23 g/mm²) than for those 3 months apart (CoR = ±0.52 g/mm²). Threshold measurements at the inferior conjunctiva, in contrast, were poorly repeatable (CoR = ±12.78 g/mm²). Cochet-Bonnet esthesiometry is repeatable when performed on the central cornea on the same day and 3 months apart, but this instrument is not recommended for conjunctival threshold measurements.

Degeneration and regeneration of corneal nerves in response to HSV-1 infection.

Herpes simplex virus type 1 (HSV-1) infection is one cause of neurotrophic keratitis, characterized by decreases in corneal sensation, blink reflex, and tear secretion as consequence of damage to the sensory fibers innervating the cornea. Our aim was to characterize changes in the corneal nerve network and its function in response to HSV-1 infection. C57BL/6J mice were infected with HSV-1 or left uninfected. Corneas were harvested at predetermined times post infection (pi) and assessed for β III tubulin, substance P, calcitonin gene-related peptide, and neurofilament H staining by immunohistochemistry (IHC). Corneal sensitivity was evaluated using a Cochet-Bonnet esthesiometer. Expression of genes associated with nerve repair was determined in corneas by real time RT-PCR, Western blotting, and IHC. Semaphorin 7A (SEMA 7A) neutralizing antibody or isotype control was subconjunctivally administered to infected mice. The area of cornea occupied by β III tubulin immunoreactivity and sensitivity significantly decreased by day 8 pi. Modified reinnervation was observed by day 30 pi without recovery of corneal sensation. Sensory fibers were lost by day 8 pi and were still absent or abnormal at day 30 pi. Expression of SEMA 7A increased at day 8 pi, localizing to corneal epithelial cells. Neutralization of SEMA 7A resulted in defective reinnervation and lower corneal sensitivity. Corneal sensory nerves were lost, consistent with loss of corneal sensation at day 8 pi. At day 30 pi, the cornea reinnervated but without recovering the normal arrangement of its fibers or function. SEMA 7A expression was increased at day 8pi, likely as part of a nerve regeneration mechanism.

Is Corneal Sensitivity Sex Dependent?

Purpose:To determine whether corneal sensitivity is different between the two genders.Methods:Corneal sensitivity of 130 normal volunteers, including 77 women and 53 men aged 20-35 years, with no history of previous ocular surgery was measured using the Cochet-Bonnet esthesiometer. Measurements were done on five corneal regions: central, nasal, inferior, temporal and superior. The findings were compared between men and women using the non-parametric Mann-Whitney U test.Results:Mean age of male subjects was 28.0 years and that of female participants was 26.8 years (P = 0.063). There was a significant difference in corneal sensitivity between men and women in the superior (P = 0.013), temporal (P = 0.020) and inferior (P = 0.046) regions. There was no significant difference in corneal sensitivity in the central (P = 0.862) and nasal (P = 0.273) regions.Conclusion:Except for the central and nasal regions, corneal sensitivity is significantly higher in men as compared to women. The reason for this difference is not yet evident.

The conjunctival sensitivity in soft contact lens wearers.

We determined the influence of soft contact lenses (SCLs) on conjunctival sensitivity. A total of 26 volunteers (11 males, 15 females; mean age 28.3 ± 4.6 years; range 22-39 years) without dry eye were enrolled in the study. Subjects with a low corneal touch threshold, atopic keratoconjunctivitis, or vernal keratoconjunctivitis were excluded. In 26 participants, 12 were disposable SCL wearers. Touch thresholds were determined using a Cochet-Bonnet esthesiometer with a 0-60 mm nylon monofilament in 5 mm increments. The length (mm) was converted to tension (g/mm(2)). Mean touch sense thresholds in the SCL wearers (n = 12) and non-wearers (n = 14) were 10.7 ± 2.57 and 24.6 ± 7.3 g/mm(2) in the whole conjunctiva, and 9.07 ± 3.02 and 19.2 ± 7.8 g/mm(2) in the upper palpebral conjunctiva, respectively. Significant differences were observed in all locations (p < 0.01). The enhanced conjunctival sensitivity associated with SCL use may contribute to the dry eye-like symptoms in SCL users who do not have dry eye.

Mechanical sensitivity of the human conjunctiva.

The aim of this study was to map the sensitivity of the marginal and other conjunctival regions and to investigate changes in the sensitivity of these regions when determined in the morning and evening. Thirty-five healthy, noncontact lens wearers (20 female, 15 male; age 27.7 ± 7.3 years) were enrolled. Mechanical sensitivity was measured at 8 locations on the ocular surface and adnexa (cornea, marginal, bulbar, and tarsal conjunctiva) using a Cochet-Bonnet esthesiometer (0.12-mm diameter filament). A subgroup of 11 subjects (6 female, 5 male; age 28.9 ± 9.9 years) returned after 12 hours when this protocol was repeated. The cornea was found to be the most sensitive region (all P < 0.001). The marginal conjunctiva showed greater sensitivity than did the bulbar and tarsal conjunctiva (all P < 0.001). The temporal marginal conjunctiva was more sensitive than the central marginal conjunctiva (all P < 0.05). No difference in marginal conjunctival sensitivity was found between upper and lower eyelids (all P > 0.05). The upper tarsal conjunctiva was more sensitive than the lower tarsal conjunctiva (P = 0.04). There was no significant difference in the sensitivity determined in the morning and the evening for any of the locations investigated (Bonferroni adjusted, P > 0.006). This work has demonstrated that the marginal conjunctiva was the most sensitive of all the conjunctival regions and that this does not alter over the course of the day.

Corneal Sensitivity and Tear Function in Neurodegenerative Diseases

Purpose: To measure corneal sensitivity and tear function in neurodegenerative diseases (NDs) and to compare them with age and sex-matched controls.Methods: Twenty patients with Alzheimer's disease (AD), 20 patients with multiple sclerosis (MS), 30 patients with Parkinson's disease (PD), 10 patients with Friedreich's ataxia (FA) and 21 patients with epilepsy (EP) who were recruited from the Kırıkkale University Neurology Department during 2012 were included in this prospective study. Five groups of age and sex-matched subjects were selected as controls. Corneal sensitivity was measured using a Cochet–Bonnet esthesiometer. Tear function tests included tear break-up time (TBUT) and Schirmer's 1 tests.Results: Compared to their controls, mean corneal sensitivity was significantly reduced in AD, MS, PD and EP patients (all p < 0.05), mean TBUT level was significantly shorter in patients with AD and MS (all p < 0.05) and mean Schirmer's 1 test score was significantly lower in EP patients (p < 0.05). When all groups were compared with each other, reduction of mean corneal sensitivity in AD and PD groups were significantly more than in FA and MS groups (overall p = 0.034). Mean TBUT levels in AD, MS and PD groups were significantly shorter than in FA and EP groups (overall p = 0.001). Mean Schirmer's 1 test scores in AD and PD groups were significantly lower than in MS, FA and EP groups (overall p = 0.040).Conclusions: Neurodegenerative diseases may be associated with reduced corneal sensitivity and abnormal tear function.

Corneal nerve alterations in different stages of Fuchs' endothelial corneal dystrophy: an in vivo confocal microscopy study.

To analyze potential alterations in corneal nerve morphology and function in different stages of Fuchs' endothelial corneal dystrophy (FECD). Thirty eyes with FECD underwent in vivo confocal microscopy using the Heidelberg Retina Tomograph II (HRT II; Heidelberg Engineering, Heidelberg, Germany) and the Rostock Cornea Module (RCM) to quantify the morphology of the central subbasal corneal nerve plexus (total nerve length, total nerve number, number of main nerve trunks, number of nerve branches) as well as esthesiometry (using the Cochet-Bonnet esthesiometer) of the central cornea to determine central corneal sensation as a measure of nerve function. Findings were correlated with an age-matched control group of 30 healthy individuals. Comparisons to biomicroscopical stage of FECD, visual acuity and central corneal thickness were performed using Spearman correlation. Depending on slit-lamp examination, all 30 eyes were classified into FECD stage 1-4 (stage 1: six eyes; stage 2: 15 eyes; stage 3: six eyes; stage 4: three eyes). Total nerve length (ρ = -0.8, p < 0.001), total nerve number (ρ = -0.7, p < 0.001), number of main nerve trunks (ρ = -0.6, p < 0.001), and number of nerve branches (ρ = -0.7, p < 0.001) decreased significantly with increasing FECD stages. Comparing to the visual acuity, significant positive correlations were found for total nerve length (ρ = 0.5, p = 0.012), total nerve number (ρ = 0.5, p = 0.005), number of main nerve trunks (ρ = 0.4, p = 0.017), and number of nerve branches (ρ = 0.5, p = 0.009). With central corneal thickness, there were significant inverse correlations for total nerve length (ρ = -0.6, p = 0.001), total nerve number (ρ = -0.5, p = 0.012), number of main nerve trunks (ρ = -0.4, p = 0.015), and number of nerve branches (ρ = -0.4, p = 0.017). Central corneal sensation was full in all FECD stage 1, stage 2 and stage 3 eyes, but mildly reduced in FECD stage 4 eyes. Increasing severity of Fuchs' endothelial corneal dystrophy (FECD) is concurrent with marked attenuation of the density, as well as mild diminishment of the function, of the subbasal corneal nerve plexus in late stage of the disease.

Evaluation of standardized endodontic paper point tear test in New Zealand white rabbits and comparison between corneal sensitivity followed tear tests.

To evaluate endodontic paper point tear test (PPTT) in rabbits and compare changes in corneal touch threshold (CTT) induced by Schirmer tear test (STT) and PPTT. Normal corneal sensitivity recovery time after both tear tests was also measured. Also, mean PPTT and STT values were obtained. Tear production of 20 eyes, from 10 rabbits, was evaluated using STT and the PPTT. Central corneal touch threshold was measured by a Cochet-Bonnet esthesiometer before any tear test was performed (zero time), immediately after the test (1min), and consecutively at 6, 11, 16, and 26min. Tests were conducted on three consecutive days: Day 1 - control condition, no tear tests performed only the CTT; Day 2 - CTT before and after PPTT; and Day 3 - CTT before and after STT. CTT values were compared using repeated measures ANOVA. Corneal touch threshold was significantly increased for at least 16min after STT, indicating STT causes corneal discomfort. No difference was found between CTT following PPTT and controls, indicating PPTT caused minimal corneal discomfort. The mean (±SD) value for STT was 5.2±1.0mm/min and for PPTT was 13.8±1.5mm/min. The aqueous fraction of rabbit's tears can be successfully measured by PPTT. This report established reference values for PPTT in rabbits. Additionally, the absence of a significant difference in CTT after PPTT compared with controls shows that PPTT is well tolerated by rabbits. Considering the improved comfort (compared with STT), accuracy, and low cost, PPTT is a bona fide method of measuring aqueous tear production in rabbits.

Evaluation of the diagnostic value for meibomian gland dysfunction examinations

To evaluate the sensitivity and specificity of clinical examinations in meibomian gland dysfunction (MGD). A prospective case-controlled study. Fifty-two patients with MGD and 32 healthy age- and sex-matched control subjects were included from January to August 2013. All subjects were underwent the examinations sequentially as follows: evaluation of ocular surface disease symptoms using the Ocular Surface Disease Index (OSDI); lid margin and ocular surface examination by slit lamp microscrope; infrared meibomian photography; cornea sensation testing using the Cochet-Bonnet esthesiometer; tear film break-up time (BUT); corneal and conjunctival staining (Oxford scale); and Schirmer I test. One eye of each subject was included in the study. The parameters between MGD group and the control group were compared using the independent-samples T test. Spearman's correlation analysis was used to analyze the correlation of each parameter of MGD group. Receiver operating characteristic curve (ROC curve) and area under the curve (AUC) were used to describe the accuracy of each parameter to differentiate MGD from normal eyes. OSDI score, lid margin abnormality score, miss rate of meibomian glands and corneal and conjunctival staining score were obviously higher in MGD group (36.13 ± 14.71, 2.37 ± 0.937, (52.64 ± 17.23) %, 1.06 ± 1.75) than those in control group(5.22 ± 11.97, 0.94 ± 0.564, (23.97 ± 6.36) %, 0.03 ± 0.18) (t = 10.019, 7.808, 8.796, 3.293, respectively; P < 0.01). BUT, schirmer I value and corneal sensitivity score were significantly lower in MGD group (4.57 ± 2.13, 6.04 ± 7.09, 5.77 ± 0.38) than those in control group (13.31 ± 2.54, 12.56 ± 6.99, 5.98 ± 0.07) (t = -16.97, -4.119, -3.018, respectively; P < 0.01). AUC value of BUT was the largest (0.995), and the followings were the miss rate of meibomian (0.944), OSDI (0.925) and lid margin abnormalities (0.811). The sensitivity and the specificity of BUT were 90.4% and 100.0%; the miss rate of meibomian were 76.9% and 100.0%; OSDI were 97.4% and 87.1%; and lid margin abnormalities were 79.5% and 79.4%. The diagnostic value of these four parameters were better than the rest ones. BUT and the miss rate of meibomian have great value in diagnosis of MGD. Patients considered MGD can be performed these examinations to confirm the diagnosis.