Corneal Sensitivity In Patients Research Articles

Combination therapy with 3% diquafosol tetrasodium ophthalmic solution and sodium hyaluronate: an effective therapy for patients with dry eye after femtosecond laser-assisted in situ keratomileusis.

To assess the effect of combination therapy with 3% diquafosol tetrasodium (DQS) and sodium hyaluronate (HA) for dry eye after femtosecond laser-assisted in situ keratomileusis (FS-LASIK). Prospective nonrandomized comparative trial. The prospective study included 80 eyes of 40 patients who underwent FS-LASIK with or without preoperative dry eye. Patients were divided into a combination group and a HA group according to their willingness and the doctor's advice. The combination group was treated with DQS six times a day and HA four times a day, and the HA group was treated with HA four times a day after FS-LASIK. Ocular surface disease index (OSDI), ocular symptom score, vision-related score, environmental score, tear meniscus height (TMH), first non-invasive tear breakup time (NIBUT-First), average non-invasive tear breakup time (NIBUT-Ave), tear breakup time (TBUT), Schirmer I test (SIT), corneal fluorescein staining score (CFS), bulbar redness score, limbal redness score, lipid layer grade (LLG), meiboscore, lid margin abnormality, corneal sensitivity, and corneal nerve parameters were examined before surgery and at 1 week and 1 month after surgery. Surface regularity index (SRI) was also examined before surgery and at 1 month postoperatively. OSDI score (p = 0.024) and vision-related score (p = 0.026) were significantly lower in the combination group than in the HA group at 1 month after FS-LASIK, especially in patients with preoperative dry eye symptoms. The increasements of CFS (p = 0.018), bulbar redness score (p = 0.021), and limbal redness score (p = 0.009) were significantly lower in the combination group than in the HA group at 1 week after FS-LASIK. But other ocular surface parameters showed no difference between both groups at 1 week and 1 month after FS-LASIK. LLG was significantly higher in the combination group than in the HA group at 1 week (p = 0.004) and 1 month (p < 0.001) after surgery, especially in patients with high meiboscore. Additional DQS significantly improved corneal sensitivity in patients without preoperative dry eye symptoms at 1 month after FS-LASIK (p = 0.041). The combination therapy with DQS and HA significantly relieved subjective symptoms, improved ocular surface status, and had the potential to promote corneal nerve growth in patients after FS-LASIK.

Evaluation of Corneal Sensitivity and Quadrature Variability in Patients with Diabetic Neuropathy.

The purpose of the study was to evaluate the corneal sensitivity and its quadrature variability in patients with diabetic neuropathy (DN) diagnosed with electromyography and to compare these results with age- and sex-matched healthy individuals. The left eyes of 32 patients who applied for refraction or fundus examination and had a diagnosis of DN by electromyography in their medical history were included in this study. Corneal sensitivity was evaluated using the Cochet-Bonnet esthesiometer (Luneau, Paris) in five zones: central, nasal, superior, temporal, and inferior. The measurements of the patients were compared with the measurements of 32 age- and sex-matched healthy volunteers. Furthermore, the measurements of five corneal zones were compared with each other, and the level of correlation was investigated in each group. The central corneal sensitivity values were measured as 4.12 ± 1.04 (mm) and 5.92 ± 0.14 (mm) (P < 0.001). While the sensitivity values at the superior, inferior, nasal, and temporal quadrants were detected as 5.85 ± 0.21, 5.85 ± 0.26, 5.94 ± 0.13, 5.93 ± 0.13, and 5.92 ± 0.14 (mm) in the control group, it was measured as 3.67 ± 0.66, 3.67 ± 0.62, 3.67 ± 0.62, and 3.89 ± 0.73 (mm) in the DN group, respectively. The corneal sensitivity values were all found to be significantly lower in the DN group (P < 0.001 for all parameters) at all quadrants as well as the central cornea. Furthermore, a moderate positive correlation between all five zones in the control group and a very strong positive correlation in the DN group were found in terms of the corneal quadrature sensitivity. The current study revealed a significant reduction in corneal sensitivity in patients with DN. In both the control group and DN group, all corneal zones showed positive correlations which show the consistency of the measurement in different quadratures. Evaluating corneal sensitivity with a Cochet-Bonnet esthesiometer might serve as a useful screening tool in detecting neuropathy development. By taking the necessary precautions, further damage can be prevented.

Corneal sensitivity in patients with lamellar ichthyosis

Corneal sensitivity in patients with lamellar ichthyosis

Evaluation of corneal sensitivity in multiple sclerosis patients.

Purpose:To measure the corneal sensitivity in patients with multiple sclerosis (MS), to compare it with normal values and to study its correlation with different disease characteristics.Methods:Corneal sensitivity of 28 MS patients was compared to corneal sensitivity of 28 age- and gender-matched normal controls. Corneal sensitivity was measured using the Cochet-Bonnet esthesiometer and was correlated to the duration, type and severity indexes of the disease.Results:Corneal sensitivity was comparable between both groups (P = 0.79). No statistically significant correlation was found between corneal sensitivity and the duration of MS (P = 0.55) nor the severity indexes of MS (expanded disability status scale [EDSS] P = 0.52, global multiple sclerosis severity score [MSSS] P = 0.64). Following subgroup analysis, only the primary progressive (PPMS) form of MS had a reduced corneal sensitivity with P = 0.023, while remittent-recurrent (RRMS), secondary progressive (SPMS), and clinically isolated (CIS) forms of MS did not have any reduction in the corneal sensitivity. “ROC curve analysis” showed an area under the curve of 0.48.Conclusion:In the exception of PPMS subtype, MS patients have similar corneal sensitivity in comparison to controls. Cochet-Bonnet esthesiometer does not seem to be a good diagnostic tool or a disease severity marker for patients with MS.

The relationship between corneal subbasal nerve density and corneal sensitivity in patients with Fuchs endothelial corneal dystrophy.

Purpose:The aim of this study was to investigate the association between alterations in corneal subbasal nerve plexus and tactile corneal sensitivity in patients with Fuchs’ endothelial corneal dystrophy (FECD).Methods:This retrospective, cross-sectional study included 24 (10 M/14 F) patients with FECD and 25 age- and sex-matched (10 M/15 F) healthy subjects as controls. Subjects with FECD were classified as having early (grades 1 and 2) and late (grades 3 and 4) disease. All subjects underwent central corneal tactile sensitivity measurements with the Cochet–Bonnet esthesiometer (Luneau Ophthalmologie, Chartres, France) and subbasal nerve density evaluation using in vivo confocal microscopy (IVCM). Association between corneal nerve plexus density and corneal sensitivity alterations were evaluated using the Mann–Whitney U test and the Spearman correlation test.Results:Compared to healthy subjects (mean age = 60.4 ± 7.5 years), patients with FECD (mean age = 60.6 ± 8.0 years) had worse central corneal sensitivity scores (5.9 ± 0.1 cm vs. 4.2 ± 0.8 cm; P < 0.001), reduced corneal nerve fibers (3.4 ± 1.3 nerves/frame vs. 5.0 ± 0.9 nerves/frame; P < 0.001) and lower corneal subbasal nerve plexus densities (2229.4 ± 364.3 μm/mm2 vs. 1901.6 ± 486.8 μm/mm2; P = 0.050). Patients with late stage FECD demonstrated lower subbasal nerve densities as compared to those with early disease (2204.3 ± 313.1 μm/mm2 (range = 1523–2552 μm/mm2); 1397.1 ± 227.4 μm/mm2 (range = 1120-1834 μm/mm2); P < 0.001). In the FECD group, subbasal nerve density was found to be directly correlated with corneal sensitivity scores (r = 0.457, P = 0.025).Conclusion:Progressive loss of the corneal subbasal nerve plexus appears to be a consistent feature of FECD. Reduction of the corneal nerve plexus parallels the decrease in corneal sensitivity in this patient population.

The inter-eye difference in corneal sensitivity in patients with infectious ulcers as measured with the Cochet-Bonnet esthesiometer

Background: The purpose of this study was to quantify the inter-eye difference in corneal sensations in patients with infectious corneal ulcers using the Cochet-Bonnet esthesiometer (CBE). Material and methods: Patients with unilateral corneal ulcers of at least 1.5 mm of the clear cornea in all quadrants meeting the study criteria were identified and enrolled. The clinical features with their etiologies were noted. The corneal sensations were measured with CBE in all four quadrants. Patients were further sub-categorized based on the surface area and the “time to heal” of the ulcers for further correlation and analysis. Results: This was a cross-sectional study conducted at a tertiary care center. The study included 35 patients, with the majority (30 patients, 85.7%) diagnosed with fungal etiology. The average corneal sensations in the ulcer and the normal eyes were 52.29 mm and 57.36 mm, respectively. The inter-eye differences were 3.93 mm (p = 0.06) and 6.55 mm (p = 0.04) among patients with an average surface area of ≤ 10 mm 2 and > 10 mm 2 , respectively. Patients who took up to 30 days and > 30 days to had inter-eye differences in a sensation of 0.71 mm (p = 0.04) and 6.14 mm (p = 0.05), respectively. Conclusions: The mean corneal sensations in all quadrants were less significant in the infectious ulcer eyes than normal eyes. Infectious ulcers with a surface area of > 10 mm2 had greater inter-eye differences in their corneal sensitivities. Patients who took a longer time to heal of > 30 days showed a significant and greater inter-eye difference in their corneal sensitivities.

Long-term restoration of corneal sensitivity in neurotrophic keratopathy after rhNGF treatment.

To report the long-term effects of the new rhNGF treatment on corneal sensitivity in patients with. We present three cases of corneal ulcers due to NK that were treated with rhNGF. In each patient wound healing evolution was documented by clinical pictures and corneal sensitivity measured by Cochet-Bonnet aesthesiometry. Best corrected visual acuity and Type I Schirmer test were also assessed neurotrophic keratopathy.All patients healed within 8 weeks and NK showed no recurrences in the mean follow-up period of 35 weeks. Each subject showed a significant increase of corneal sensitivity and tear secretion, with concomitant improvement in visual acuity. Corneal sensitivity, measured by Cochet-Bonnet aesthesiometer, markedly increased in all eyes. Further studies are warranted to demonstrate a possible mechanism of nerve restoration with rhNGF treatment.

OUR EXPERIENCE OF USING AUTOLOGICAL BLOOD SERUM IN COMPLEX TREATMENT OF BACTERIAL CORNEAL ULCERS IN PATIENTS WITH DIABETES MELLITUS DEPENDING ON THESEVERETY OF DIABETIC POLYNEUROPATHY

Summary. Diabetic keratopathy, which develops against the background of diabetic corneal neuropathyshould be taken into account when choosing tactics for the treatment of bacterial corneal ulcers in patients with diabetes mellitus.&#x0D; The aim of the study was to determine the effectiveness of treatment of bacterial corneal ulcers with the help of additional local use of autological serum eye drops in patients with type 1 diabetes depending on the severity of diabetic polyneuropathy (DPN).&#x0D; Materials and methods. The results of observation of 10 patients (10 eyes) with bacterial corneal ulcer and type 1 diabetes mellitus, in which delayed healing of corneal ulcer defect were noted and the absence of microorganisms ware confirmed by repeated bacteriological examinations of corneal smears and scrapings,were analyzed. In addition to standard therapy, all patients 2 weeks after the start of treatment were additionally prescribed eye drops with autologous serum. Patients were divided into 2 groups according to the stage of severity of DPN: the first group consisted of 5 patients with symptomatic stage, the second - 5 patients with a stage of severe complications. In addition to standard, ophthalmic examination methods included bacteriological examination, fluorescein test, OCT of the anterior segment of the eye on the device TOPCON 3D OCT-2000, non-contact examination of corneal sensitivity.&#x0D; Results and discussion. It was found that the threshold of corneal sensitivity in patients with bacterial corneal ulcer at the stage of severe complications of DPN was higher than that in symptomatic DPN by an average of 16.6 % during the observation. The degree of pericorneal injection and infiltration of the cornea, as well as the size and depth of the ulcerative defect of the cornea at the stage of severe complications exceeded the corresponding indicators of patients with symptomatic DPN during the observation. Normalization of conjunctival color and reepithelialization of the cornea in all patients with severe complications occurred 3 days later than in patients with symptomatic DPN.&#x0D; Conclusions. The course of bacterial keratitis in patients with diabetes mellitus depends on the severity of DPN: a pronounced violation of corneal innervation at the stage of severe complications of DPN, manifested by a decrease in its sensitivity, leads to prolongation of treatment, even with additional use of eye drops with autologous serum.

Establishing the normal range of corneal sensitivity in an Indian Population using the Cochet–Bonnet esthesiometer

Background: The human cornea is the most densely innervated tissue, and the corneal sensitivity is a measure of its function and an indicator of the integrity of the protective mechanism. Corneal sensitivity plays a vital role in the protection and maintenance of corneal health and is known to vary with race, age, region, climate, environment, and the time of the day. The study was aimed to quantify and establish the range of corneal sensations in different age groups in an Indian population using the Cochet–Bonnet Esthesiometer (CBE). Materials and Methods: This was a cross-sectional study done at a tertiary care center in South India, between January and April 2018. One hundred and fifty patients (30 patients stratified by age into five groups) were enrolled after informed consent. The corneal sensations were measured using CBE by a single examiner in a specified period of a day over five regions and the data analyzed. Results: The average measured corneal sensitivity was 58.36 (21–30 years), 57.96 (31–40 years), 56.43 (41–50 years), 56.40 (51–60 years), and 54.84 (>60 years) mm, respectively. The frequency of having maximal measurable sensations (60 mm) in all the tested regions dropped with increasing age from 46.67% to 16.67%. All regions showed a sensitivity drop with an increase in age, the maximum in the nasal quadrant and the least drop in the central region. No statistically significant difference in the corneal sensitivity was found between the genders. Conclusions: An inverse linear correlation between the corneal sensitivity and age was evident. The central and the superior regions are the most and least sensitive regions of the cornea, respectively, in our study population. The varied pattern of change in corneal sensations in different populations highlights the importance of establishing normal ranges of corneal sensitivity in patients from different ethnic and geographical backgrounds.

Randomized Controlled Study to Investigate the Effect of Topical Diquafosol Tetrasodium on Corneal Sensitivity in Short Tear Break-Up Time Dry Eye.

Complex mechanisms underlie dry eye (DE) symptom provocation. In particular, corneal hypersensitivity may provoke symptoms in short tear break-up time (BUT) DE characterized by tear film instability. We hypothesized that improved tear film stability may alleviate corneal sensitivity in patients with short tear BUT DE. Therefore, we investigated the effect of topical diquafosol tetrasodium (DQS) on corneal sensitivity in unstable tear film DE. This prospective, randomized study included 27 subjects (age: 39.1 ± 8.4years; range: 25-59years) with short tear BUT DE, defined based on the presence of DE symptoms and tear film instability. Subjects were randomly divided into DQS (3% DQS, 12 subjects) and artificial tear (AT; preservative-free AT, 15 subjects) groups. Subjects applied the medication 6 times a day for 5weeks. The perception of touch (S-touch) and pain (S-pain) sensitivity was measured using a Cochet-Bonnet esthesiometer. Tear evaluation, corneal sensitivity, and DE symptoms were compared before and after DQS or AT administration. The correlation between the improvement degrees of corneal sensitivity and DE symptoms following medication was analyzed. DQS significantly improved tear BUT and tear meniscus height (TMH) scores (p < 0.05), while AT significantly improved tear BUT (p < 0.05) but not TMH score. Mean S-pain and DE symptom scores were lower after medication use in the DQS (S-pain and DE symptoms: p < 0.05) and AT groups (S-pain: p = 0.05; DE symptoms: p < 0.05). However, S-touch did not change significantly in either group. A positive correlation was observed between the improvement degrees of S-pain and DE symptoms in the overall subjects studied. Both DQS and AT alleviate corneal hypersensitivity and DE symptoms in eyes with short tear BUT DE. However, DQS seems to be more effective to adjust tear environment, leading to the normalization of corneal sensitivity and DE symptoms. UMIN Clinical Trials Registry Identifier, UMIN000014536.

Dry Eye and Corneal Sensitivity in Patients with Type 2 Diabetes Mellitus

Dry Eye and Corneal Sensitivity in Patients with Type 2 Diabetes Mellitus

Neurotrophic factors and corneal nerve regeneration

The cornea has unique features that make it a useful model for regenerative medicine studies. It is an avascular, transparent, densely innervated tissue and any pathological changes can be easily detected by slit lamp examination. Corneal sensitivity is provided by the ophthalmic branch of the trigeminal nerve that elicits protective reflexes such as blinking and tearing and exerts trophic support by releasing neuromediators and growth factors. Corneal nerves are easily evaluated for both function and morphology using standard instruments such as corneal esthesiometer and in vivo confocal microscope. All local and systemic conditions that are associated with damage of the trigeminal nerve cause the development of neurotrophic keratitis, a rare degenerative disease. Neurotrophic keratitis is characterized by impairment of corneal sensitivity associated with development of persistent epithelial defects that may progress to corneal ulcer, melting and perforation. Current neurotrophic keratitis treatments aim at supporting corneal healing and preventing progression of corneal damage. Novel compounds able to stimulate corneal nerve recovery are in advanced development stage. Among them, nerve growth factor eye drops showed to be safe and effective in stimulating corneal healing and improving corneal sensitivity in patients with neurotrophic keratitis. Neurotrophic keratitis represents an useful model to evaluate in clinical practice novel neuro-regenerative drugs.

Bilateral tear film alterations in patients with unilateral quiescent herpes simplex keratitis

To evaluate bilateral tear function and corneal sensitivity in patients with unilateral quiescent herpes simplex keratitis (HSK) and determine the correlation between corneal sensitivity and tear secretion in both eyes. Thirty-five patients diagnosed with unilateral quiescent HSK and 35 heathy controls were included in this study. Bilateral tear osmolarity, Schirmer's test, the tear break-up time (TBUT) and corneal sensitivity were measured in all participants. In the HSK group, both eyes demonstrated a significant increase in tear osmolarity, and a decrease in Schirmer's test and the TBUT compared with healthy controls (All p<0.001). The bilateral tear osmolarity and Schirmer's test were similar, but the TBUT (4.9±2.1 versus 7.4±2.0second; p<0.001) and corneal sensitivity (35.1±1.9 versus 54.3±0.8mm; p<0.001) were significantly lower in the affected eyes. The bilateral tear osmolarity, Schirmer's test and the TBUT were significantly correlated with corneal sensitivity of the affected eye (All p<0.001). When corneal sensitivity of the unaffected eye was treated as a control variable, tear osmolarity (R=-0.626, p<0.001), Schirmer's test (R=0.739, p<0.001) and the TBUT (R=0.691, p<0.001) of the unaffected eyes were still significantly correlated with the corneal sensitivity of the affected eyes. Unilateral quiescent HSK causes bilateral tear impairment, which depends on the loss of corneal sensitivity in the affected eye. In the affected eye with severe corneal sensitivity loss, bilateral dry eye occurred.

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.

Dry Eye in Graves’ Ophthalmopathy: Correlation with Corneal Hypoesthesia

To evaluate dry eye disease and corneal sensitivity in patients with early and active Graves ophthalmopathy (GO). A total of 52 eyes of 26 patients with early GO and 74 eyes of 37 age- and sex-matched controls were included in our study. Dry eye disease was assessed based on the criteria of the International Dry Eye Workshop. Diagnosis of early GO was based on the European Group on Graves' Orbitopathy consensus statement. Clinical Activity Score (CAS) and Werner-NOSPECS Score were determined. Corneal sensitivity was assessed using a Cochet-Bonnet aesthesiometer. A total of 67.8% of patients with early GO and 13.5% of healthy controls had ocular surface dryness (p<0.001). The mean Schirmer test score was significantly lower in patients with early GO (12.88 ± 7.94 mm [right eyes] and 14.04 ± 9.00 mm [left eyes]) than in controls (18.08 ± 7.26 mm [right eyes] and 18.05 ± 7.50 mm [left eyes] [p<0.05]). The tear film break-up time was lower in patients by 5.46 seconds and 5.74 seconds in right and left eyes (p<0.001). We also found a significant reduction in corneal sensitivity in patients with early GO (4.16 ± 0.68 [right eyes] and 4.10 ± 0.89 [left eyes]) than in controls (4.70 ± 0.34 [right eyes] and 4.72 ± 0.34 [left eyes] [p<0.05]). The CAS correlated significantly with the Schirmer test (r = -0.60, p = 0.003). Dry eye is common in early GO even in the absence of apparent exophthalmos and is associated with CAS and reduced corneal sensitivity.

Changes in Corneal Sensation and Ocular Surface in Patients With Asymmetrical Keratoconus

To describe tear function, ocular surface changes, and corneal sensitivity in patients with asymmetrical keratoconus (KC). Thirty-one patients with asymmetrical KC (31 KC and 31 subclinical KC eyes) and 30 control subjects (1 eye in each subject) were enrolled in this prospective, case-control study. The patients and control subjects underwent ocular surface examinations including corneal sensitivity measurements, the Schirmer test using topical anesthesia, tear osmolarity test, and conjunctival impression cytology. Mean corneal sensitivity and Schirmer test values were significantly lower in the KC and subclinical KC eyes compared with the control eyes. The conjunctiva of KC and subclinical KC eyes showed significantly higher grades of squamous metaplasia and goblet cell loss compared with the control group. However, no significant difference in tear osmolarity was found among the groups. The corneal sensitivity and ocular surface changes were significant in the subclinical KC and KC eyes compared with the control subjects. Ocular surface disease in KC was characterized by tear deficiency disorder and abnormal impression cytology results. However, no significant difference in tear osmolarity was found among the groups. The decrease in corneal sensitivity and ocular surface change may be associated with the pathogenesis of ocular surface changes in KC and the progression of the disease.

Reduced Corneal Sensitivity in Patients With Rheumatoid Arthritis

Up to one third of rheumatoid arthritis (RA) patients complain of dry eyes. The altered corneal sensitivity can be the consequence or the cause of the chronic reduction in tear secretion, or reduced tear production can cause the change of corneal sensitivity. The aim of this study was to assess the relationship among the symptoms, signs of dry eyes, and corneal sensitivity in RA and evaluate the association among the corneal sensitivity and clinical variables of RA. A total of 106 RA patients and 40 control subjects participated in the study. Subjective symptoms of ocular dryness were explored using Ocular Surface Disease Index (OSDI), and objective signs including Schirmer test and tear break-up time (tBUT) were measured. Corneal sensitivity was determined by evaluating the corneal touch threshold using a Cochet-Bonnet esthesiometer. Clinical assessment of RA activity included C-reactive protein, Disease Activity Score 28, and Health Assessment Questionnaire. Schirmer test scores and tBUT were significantly lower and OSDI was significantly higher in RA patients. The mean corneal sensitivities significantly reduced in the patient group but failed to show any correlations with Schirmer test, tBUT, and OSDI. Corneal sensitivity showed significant negative correlation with rheumatoid factor but failed to show any correlations with C-reactive protein, Health Assessment Questionnaire, and Disease Activity Score 28. Corneal sensitivity was reduced in RA patients but failed to show any association with the subjective symptoms and objective signs of dry eyes. We could assume that reduced corneal sensitivity does not represent a sign of inflammation.

The Relationship between Subbasal Nerve Morphology and Corneal Sensation in Ocular Surface Disease

The purpose of this study was to evaluate the relationship between the in vivo confocal microscopic (IVCM) morphology of subbasal corneal nerves and corneal sensitivity in patients with ocular surface disease. Ten healthy volunteers (control group), 12 patients with dry eye (dry-eye group), and 14 patients treated with IOP-lowering topical medications (glaucoma group) were included. Central corneal sensation was measured using the contact Cochet-Bonnet esthesiometer. IVCM of the cornea was performed and the following subbasal corneal nerves parameters were analyzed: density, number, width, number of beadings, number of branching, tortuosity, and reflectivity. One eye of each subject was included in the study. Corneal sensitivity was significantly decreased in dry-eye and glaucoma patients compared with controls. The density and number of subbasal corneal nerves were also significantly decreased in dry eye and glaucoma patients compared with controls. There was no difference in terms of subbasal nerve width, number of beadings, tortuosity, reflectivity, and number of branching between the dry-eye, the glaucoma, and the control groups. In all subjects, corneal sensitivity correlated positively with the density and number of subbasal nerves; however, in the dry-eye group, corneal sensitivity correlated with the density and the number of nerves, whereas in the glaucoma group, corneal sensitivity correlated only with the tortuosity of subbasal nerves. The relationship between corneal sensation and subbasal nerve morphology, as evaluated with IVCM, depends on the pathophysiological mechanism of ocular surface disease.

Évaluation de la sensibilité cornéenne chez les patients traités médicalement pour un glaucome ou une hypertonie oculaire

To evaluate the corneal sensitivity in patients treated with intraocular pressure (IOP)-lowering medications. Chronic administration of anti-glaucoma drops is associated with numerous tissue changes on the ocular surface. The purpose of this study was to investigate the effect of these medications and their preservative, benzalkonium chloride (BAK), on corneal sensitivity. Thirty-nine patients treated for glaucoma or ocular hypertension (OHT) and nine untreated patients were included in this study. Treated patients were divided into three groups according to the daily number of preserved eyedrops (0, 1 and ≥2). Corneal sensitivity was assessed using the Cochet-Bonnet esthesiometer. All patients underwent a complete examination of the ocular surface including Schirmer testing, tear film breakup time (BUT) and corneal and conjunctival fluorescein staining. The Ocular Surface Disease Index (OSDI) questionnaire was used to evaluate symptoms. Corneal sensitivity was 58.8±2.8mm, 56.2±5.2mm, 50.3±12.5mm and 44.3±13.6mm in untreated patients, in patients treated with none, one and two or more instillations of preserved eyedrops, respectively. Corneal sensitivity in patients treated with preserved eyedrops was significantly lower as compared to untreated patients (P<0.001) and patients treated with preservative-free eyedrops (P=0.012). Corneal sensitivity of patients treated with intraocular pressure-lowering medications was negatively correlated to the number of instillations of preserved eyedrops (r=-0.390 ; P<0.001) as well as to the duration of treatment (R=-0.357 ; P=0.001). BUT and fluorescein staining were significantly altered in treated patients compared to the untreated control group ; however, no significant difference was observed between the treated groups. There was no significant difference for OSDI or Schirmer testing between the various groups. Chronic administration of BAK-containing anti-glaucoma eyedrops appears to alter corneal sensitivity. These results could explain the absence of correlation between clinical signs and symptoms sometimes observed in patients treated for glaucoma or OHT.

This issue of Acta

This issue of Acta