Central Corneal Sensitivity Research Articles

Effect of autologous serum after amniotic membrane transplantation for persistent corneal ulcers.

To investigate the effect of adding autologous serum eye drops to the postoperative regime after amniotic membrane transplantation for severe persistent corneal ulcers. Forty eyes of 40 patients with persistent corneal ulcers were randomly assigned to artificial tears (sodium hyaluronate 0.2%, ATs group, n=20) or autologous serum eye drops (ASEDs, n=20) following treatment with amniotic membrane transplantation. Digital slit lamp images were acquired from all patients before and 30d post treatment. The area with fibrovascular tissue was calculated using Image J. Central corneal sensitivity was assessed by Cochet-Bonnet aesthesiometry before and one month after treatment. Scar tissue transparency was assessed with a novel optical densitometry. Mean age of patients was 61.65±16.47y and 57.3±19.11y in the ATs group and ASEDs group, respectively. Twenty-two male and 18 female patients were included in the study. The improvement in visual acuity was significantly greater in the ASEDs group (0.14±0.04) than the ATs (0.08±0.04; P=0.00046). Cochet-Bonnet aesthesiometry improved significantly after treatment with a similar rate between groups. There were no statistically significant differences in the area of postoperative fibrovascular tissue between the two groups (P=0.082). The success rate in the two groups was similar. The difference in densitometry between the ATs and ASEDs group was statistically significant (P=0.042) with greater reduction from baseline in the ASEDS group. Autologous serum eye drops can lead to better visual acuity, more stable results and improved densitometry and should be considered in the postoperative care following amniotic membrane transplantation.

Evaluation of Two Artificial Tears Containing Hyaluronic Acid for Post Cataract Surgery Dry Eye Disease: A Randomized Controlled Trial.

This study compared the efficacy of hydroxypropyl guar (HPG)/hyaluronic acid (HA) and carboxymethylcellulose (CMC)/HA lubricant eye drops for post-cataract surgery dry eye disease (DED). This was a prospective, open-label, assessor-masked, parallel, randomized controlled study. Seventy patients with DED who underwent cataract surgery were randomized in a 1:1 ratio to receive 1-2 drops of HPG/HA or CMC/HA lubricant four times daily for 3 weeks. Efficacy assessments included changes from baseline in corneal fluorescein staining (CFS) score, Ocular Surface Disease Index score, Schirmer's test score (without anesthesia), tear break-up time, and central corneal sensitivity at weeks 1 and 3. There were 35 patients in each group. The HPG/HA group demonstrated superior improvements in CFS scores (expressed as means and standard deviations) to the CMC/HA group at week 1 ( - 1.0 [1.7] vs. - 0.1 [1.7], p = 0.039) and demonstrated comparable results at week 3 ( - 1.6 [1.8] vs. - 1.3 [1.9], p = 0.552). No statistical differences were observed in other secondary outcomes between groups at weeks 1 and 3 (p > 0.05). Only one adverse event was reported in this study, which occurred in the HPG/HA group. The AE of ocular hypertension was mild, deemed unrelated to the study treatment, and resolved within a week. The HPG/HA lubricant eye drops resulted in greater CFS scores at 1 week after treatment compared with CMC/HA drops. The HPG/HA and CMC/HA drops were safe and well tolerated. NCT06221345.

A New Treatment for Recalcitrant Neurotrophic Keratopathy of Ocular Graft-Versus-Host Disease with Virus Infection.

Neurotrophic keratopathy (NK) is a rare degenerative ocular disease that can be difficult to treat. There were no effective resolutive treatments for severe NK caused by ocular graft-versus-host disease (oGVHD) along with virus infection. To address this question, we designed a prospective cohort study to evaluate the efficacy and safety of topical recombinant human nerve growth factor (rhNGF) in patients with recalcitrant NK of oGVHD and viral infection. This prospective cohort study enrolled patients with recalcitrant NK diagnosed with oGVHD and treated with rhNGF. Clinical evaluations included the range of epithelial defects, best corrected visual acuity, intraocular pressure, slit-lamp examination, and corneal fluorescein staining. Examinations of the central corneal thickness, corneal sensitivity, and nerve fiber regeneration were performed at each visit at 4, 8, 12, 20weeks and 6months, respectively, after initiating rhNGF treatment. All enrolled patients were diagnosed with NK at stage2 (7 eyes, 63.6%) or stage3 (4 eyes, 36.4%) and responded to rhNGF treatment. Five of 11 (45.5%) and 9 of 11 eyes (81.8%) achieved complete corneal epithelial healing after 4 and 8weeks, respectively. All 11 eyes (100%) achieved complete corneal healing after 12weeks. There was also a significant reduction in the corneal ulcer area during each visit (P < 0.001), as well as in the corneal fluorescein staining score (P < 0.010). There was a significant improvement in corneal sensation when compared to the baseline (P < 0.050). Topical treatment with rhNGF effectively promoted the complete corneal healing of persistent epithelial defects and corneal ulcers in patients with recalcitrant NK in oGVHD and viral infection.

Relationship between ocular surface pain and corneal nerve loss in dry eye diabetics: a cross-sectional study in Shenyang, China

BackgroundDiabetes mellitus has been associated with increased dry eye disease (DED) and exacerbates DED pathology.ObjectiveTo investigate the potential relationship between corneal nerve loss and ocular pain among diabetic patients with...

Corneal nerve loss and increased Langerhans cells are associated with disease severity in patients with rheumatoid arthritis.

Rheumatoid arthritis (RA) is a multisystem autoimmune disorder characterized by articular and extra-articular manifestations. Neuropathy is a poorly studied manifestation of RA. The aim of this study was to utilize the rapid non-invasive ophthalmic imaging technique of corneal confocal microscopy to identify whether there is evidence of small nerve fibre injury and immune cell activation in patients with RA. Fifty consecutive patients with RA and 35 healthy control participants were enrolled in this single-centre, cross-sectional study conducted at a university hospital. Disease activity was assessed with the 28-Joint Disease Activity Score and erythrocyte sedimentation rate (DAS28-ESR). Central corneal sensitivity was measured with a Cochet-Bonnet contact corneal esthesiometer. A laser scanning in vivo corneal confocal microscope was used to quantify corneal nerve fibre density (CNFD), nerve branch density (CNBD), nerve fibre length (CNFL), and Langerhans cell (LC) density. Corneal sensitivity (P = 0.01), CNFD (P = 0.02), CNBD (P < 0.001), and CNFL (P < 0.001) were lower, and mature (P = 0.001) and immature LC densities (P = 0.011) were higher in patients with RA compared to control subjects. CNFD (P = 0.016) and CNFL (P = 0.028) were significantly lower in patients with moderate to high (DAS28-ESR > 3.2) compared to mild (DAS28-ESR ≤ 3.2) disease activity. Furthermore, the DAS28-ESR score correlated with CNFD (r = -0.425; P = 0.002), CNBD (ρ = -0.362; P = 0.010), CNFL (r = -0.464; P = 0.001), total LC density (ρ = 0.362; P = 0.010) and immature LC density (ρ = 0.343; P = 0.015). This study demonstrates reduced corneal sensitivity, corneal nerve fibre loss and increased LCs which were associated with the severity of disease activity in patients with RA.

Effect of the Preservative Benzalkonium Chloride in Prostaglandin Analogues on Corneal Sensitivity

Purpose: To investigate the effect of a prostaglandin (PG) analogue with or without preservative benzalkonium chloride (BAK) on corneal sensitivity.Methods: Central corneal sensitivity was measured prospectively with a Cochet–Bonnet esthesiometer in patients with normal tension glaucoma (NTG) or primary open angle glaucoma (POAG) before and 1 and 3 months after treatment. All patients began treatment with PG monotherapy with or without BAK preservative.Results: The study enrolled 84 patients: 52 NTG and 32 POAG. The treatment was PG with BAK preservative in 45 eyes and without BAK preservative in 39 eyes. Without BAK, the mean corneal sensitivity was 58.22 ± 3.56, 57.77 ± 4.59, and 56.33 ± 5.47 mm before and after 1 and 3 months, respectively; with BAK the mean corneal sensitivity was 58.20 ± 4.51, 56.31 ± 6.22, and 55.52 ± 6.23 mm. Corneal sensitivity was reduced significantly in patients using PG with the preservative BAK after 3 months (p = 0.033). Co-administration of artificial tears did not affect this reduction in corneal sensitivity.Conclusions: PG with the preservative BAK reduced corneal sensitivity and artificial tears did not improve this reduction. Reduced corneal sensitivity and accompanying side effects should be considered in the long-term use of PG with the preservative BAK.

Corneal Confocal Microscopy in Type 1 Diabetes Mellitus: A Six-Year Longitudinal Study.

PurposeThe current study describes corneal nerve morphology using in vivo confocal microscopy (IVCM) in patients with type 1 diabetes (T1D) who were followed up for 6 years, and it examines the relationship between corneal parameters and metabolic control of glucose and peripheral neuropathy.MethodsSixty-two participants (37 with T1D and 25 control participants) were assessed in 2011 and 2017. Participants with bilateral cataract surgery or controls who developed diabetes were excluded. All underwent HbA1c, IVCM, and central corneal sensitivity measurements at both time points in the eye previously examined. A modified total neuropathy score was obtained.ResultsParticipants were age and sex matched. The mean duration of diabetes was 32.1 ± 12.0 years at the follow-up visit. The sub-basal nerve density in participants with T1D was lower than that of the controls and did not change (mean ± SD, 11.07 ± 4.0 to 11.41 ± 4.1 mm/mm2; P = 0.71), but it showed a marginal change in controls (19.5 ± 3.7 to 21.63 ± 4.03 mm/mm2; P = 0.06). The corneal sensitivity in T1D did not change (1.3 ± 1.5 to 1.4 ± 1.0 mbar; P = 0.8), and it declined in the controls (0.2 ± 0.3 to 0.6 ± 0.3 mbar; P < 0.001). There were no significant changes in HbA1c (60.5 ± 12.5 to 61.6 ± 13.7 mmol/mol) or in modified total neuropathy scores (2.4 ± 3.2 to 3.4 ± 3.8; P = 0.2).ConclusionsThe corneal nerve damage and poorer corneal sensitivity reported in the patients with T1D did not change and displayed improvement with good glycemic control.Translational RelevanceThe corneal nerve changes may be of more value in those with a shorter duration of diabetes for the timely prediction of at-risk individuals likely to develop peripheral neuropathy, particularly in type 1 diabetes.

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.

Subclinical Corneal Nerve Fiber Damage and Immune Cell Activation in Systemic Lupus Erythematosus: A Corneal Confocal Microscopy Study.

PurposeThe purpose of this study was to evaluate the utility of corneal confocal microscopy (CCM) in identifying small nerve fiber damage and immune cell activation in patients with systemic lupus erythematosus (SLE).MethodsThis cross-sectional comparative study included 39 consecutive patients with SLE and 30 healthy control participants. Central corneal sensitivity was assessed using a Cochet-Bonnet contact corneal esthesiometer and a laser scanning CCM (Heidelberg, Germany) was used to quantify corneal nerve fiber density (CNFD), nerve branch density (CNBD), nerve fiber length (CNFL), and Langerhans cell (LC) density.ResultsAge was comparable among patients with SLE (33.7 ± 12.7) and controls (35.0 ± 13.7 years, P = 0.670) and the median duration of disease was 3.0 years (2.0–10.0 years). CNBD (P = 0.003) and CNFL (P = 0.019) were lower and mature LC density (P = 0.002) was higher, but corneal sensitivity (P = 0.178) and CNFD (P = 0.198) were comparable in patients with SLE compared with controls. The SELENA-SLEDAI score correlated with CNFD (ρ = −0.319, P = 0.048) and CNFL (ρ = −0.373, P = 0.019), and the total and immature LC densities correlated with CNBD (ρ = −0.319. P = 0.048, and ρ = −0.328, P = 0.041, respectively). Immature LC density was higher (P = 0.025), but corneal sensitivity and nerve fiber parameters were comparable between patients with (33%) and without neuropsychiatric symptoms and SLE.ConclusionsCorneal confocal microscopy identifies distal corneal nerve fiber loss and increased immune cell density in patients with SLE and corneal nerve loss was associated with disease activity.Translational RelevanceCorneal confocal microscopy may enable the detection of subclinical corneal nerve loss and immune cell activation in SLE.

Comparison of early changes in ocular surface markers and tear inflammatory mediators after femtosecond lenticule extraction and FS-LASIK.

To compare the short-term impacts of femtosecond lenticule extraction (FLEx) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) on ocular surface measures and tear inflammatory mediators. This prospective comparative nonrandomized clinical study comprised 75 eyes (75 patients). Totally 20 male and 15 female patients (age 21.62±3.25y) with 35 eyes underwent FLEx, and 26 male and 14 female patients (age 20.18±3.59y) with 40 eyes underwent FS-LASIK. Central corneal sensitivity, noninvasive tear breakup time, corneal fluorescein staining, Schirmer I test, tear meniscus height, and ocular surface disease index were evaluated in all patients. Tear concentrations of nerve growth factor (NGF), interleukin-1α (IL-1α), transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and matrix metalloproteinase-9 (MMP-9) were assessed by multiplex antibody microarray. All measurements were performed preoperatively, and 1d, 1wk, and 1mo postoperatively. Patients who underwent FLEx exhibited a more moderate reduction in central corneal sensation and less corneal fluorescein staining than those in the FS-LASIK group 1wk after the procedure (P<0.01). NGF was significantly higher 1d and 1wk after surgery in the FS-LASIK group than in the FLEx group (P<0.01). By contrast, compared to those in the FLEx group, higher postoperative values and slower recovery of tear TGF-β1, IL-1α, and TNF-α concentrations were observed in the FS-LASIK group (P<0.01). Tear concentrations of NGF, TGF-β1, TNF-α, and IL-1α were correlated with ocular surface changes after FLEx or FS-LASIK surgery. There is less early ocular surface disruption and a reduced inflammatory response after FLEx than after FS-LASIK. NGF, TGF-β1, TNF-α, and IL-1α may contribute to the process of ocular surface recovery.

Comparision on the effects of ocular surface tear system between two novel corneal refractive surgery

Objective To investigate the different effects of small incision lenticule extraction(SMILE) and sub-Bowman keratomileusis (SBK) on ocular surface tear system. Methods A prospective study. Total of 63 eyes of 63 cases were selected randomly in this study. There were 33 eyes who underwent SMILE and 30 eyes who underwent SBK. Corneal fluorescein(FL) staining, tear break-up time (BUT), Schirmer I test (SIT), central corneal sensitivity and ocular surface disease index (OSDI) score were estimated periodically before and 3 months after surgery. Results The FL scores in SMILE group were lower than those in SBK group at 1 week postoperatively (Z=2.455, P=0.014). The BUT of SMILE group were larger than those of SBK group at 1 (t=2.432, P=0.018) at 3 months postoperatively (t=2.150, P=0.036). The central corneal sensitivity was observed in SMILE group at any visit postoperatively were higher than that in SBK group (P 0.05). Conclusion The effect of SMILE surgery on ocular surface tear system is smaller than that of SBK. And the former recovers with less time. Key words: Small incision lenticule extraction; Sub-Bowman keratomileusis; Ocular surface; Tear

Impact of 0.1% sodium hyaluronate and 0.2% sodium hyaluronate artificial tears on postoperative discomfort following cataract extraction surgery: a comparative study

BackgroundRecent artificial tear preparations have provided 0.2% concentration of sodium hyaluronate. However, no published data exist on their potential superiority against 0.1% in alleviating dry-eye-disease symptoms in cataract extraction surgery.MethodsA total of 180 patients that underwent cataract extraction surgery were randomly divided into 2 groups according to their postoperative regime: Study group (SG) received fixed combination of tobramycin and dexamethasone (FCTD) quid for 3 weeks, and additionally 0.2% sodium hyaluronate provided in the COMOD® device quid for 6 weeks. Control group (CG) received fixed combination of tobramycin and dexamethasone (FCTD) quid for 3 weeks, and additionally 0.1% sodium hyaluronate provided in the COMOD® device quid for 6 weeks. The following indexes were evaluated at 3 postoperative checkpoints: 1) Surface discomfort index (SDI) which was derived by four direct 10-scale Likert-type questions that were addressed to the patient and pertained to: a) foreign body sensation (FBS), b) blinking discomfort (BD), c) stinging sensation (SS), d) tearing sensation (TS), 2) Tear break-up time (TBUT), 3) Schirmer’s test, 4) Central corneal thickness (CCT), and 4) Central Corneal Sensitivity (CCS).ResultsBoth groups showed reduced CCS values at all postoperative examination points; however, SG participants had significantly better CCS (all p < 0.05). SG had better TBUT than CG at the 3rd (p = 0.03) and 6th examination points (p = 0.04). Moreover, SG had better SDI scores at the 3rd (SDI = 9.26 ± 0.55) and 6th weeks (SDI = 9.47 ± 0.48) vs. CG participants (p = 0.03 and p < 0.01, respectively).ConclusionThe increased 0.2% sodium hyaluronate concentration in the artificial tears provided in the COMOD® device seems to address dry-eye-disease symptoms better in patients who underwent phacoemulsification surgery than the 0.1% concentration.Trial registrationClinicalTrials.govIdentifier:NCT03705949 Oct 15, 2018, retrospectively registered.

Short-Term Effects of Overnight Orthokeratology on Corneal Sensitivity in Chinese Children and Adolescents.

Purpose To assess the effects of the 3-month period of orthokeratology (OK) treatment on corneal sensitivity in Chinese children and adolescents. Methods Thirty subjects wore overnight OK lenses in both eyes for 3 months and were assessed at baseline, 1 day, 1 week, 1 month, and 3 months after the treatment. Changes in corneal sensitivity were measured by the Cochet–Bonnet (COBO) esthesiometer at the corneal apex and approximately 2 mm from the temporal limbus. Changes in refraction and corneal topography were also measured. Results Central corneal sensitivity suffered a significant reduction within the first month of the OK treatment period but returned to the baseline level at three months (F = 3.009, P=0.039), while no statistically significant difference occurred in temporal sensitivity (F = 2.462, P=0.074). The baseline of central corneal sensitivity correlated with age (r = −0.369, P=0.045). A marked change in refraction (uncorrected visual acuity, P < 0.001; spherical equivalent, P < 0.001) and corneal topographical condition (mean keratometry reading, P < 0.001; eccentricity value, P < 0.001; Surface Regularity Index, P < 0.001) occurred, but none of these measurements were correlated with corneal sensitivity. Conclusions A 3-month period OK treatment causes a reduction in central corneal sensitivity in Chinese children and adolescents but with a final recovery to the baseline level, which might be because neuronal adaptation occurred earlier in children and adolescents than in adults.

Corneal confocal microscopy detects corneal nerve damage and increased dendritic cells in Fabry disease

Fabry disease is characterised by neuropathic pain and accelerated vascular disease. This study evaluates the utility of corneal confocal microscopy (CCM) to non-invasively quantify corneal nerve and endothelial cell morphology and dendritic cell (DC) density in relation to disease severity in subjects with Fabry disease. Seventeen consecutive participants with Fabry disease and 17 healthy control subjects were included in this cross-sectional study. Fabry disease severity was measured using the Mainz Severity Score Index (MSSI). Central corneal sensitivity was assessed with a contact corneal esthesiometer. There was a significant reduction in the corneal sensitivity (5.75 [5.25–6.00] vs. 6.00 [6.00-6.00] cm, P = 0.014), nerve fiber density (NFD) (26.4 ± 10.1 vs. 33.7 ± 7.9 fibers/mm2, P = 0.025) and nerve fiber length (NFL) (15.9 ± 3.4 vs. 19.5 ± 4.4 mm/mm2, P = 0.012) and an increase in DC density (38.3 [17.5–97.3] vs. 13.5 [0–29.4] cells/mm2, P = 0.004) in subjects with Fabry disease compared to the healthy control subjects. The total MSSI score correlated with NFD (ρ = −0.686; P = 0.006), NFL (ρ = −0.692; P = 0.006), endothelial cell density (ρ = −0.511; P = 0.036), endothelial cell area (ρ = 0.514; P = 0.036) and α-galactosidase A enzyme activity (ρ = −0.723; P = 0.008). This study demonstrates reduced corneal sensitivity, corneal nerve fiber damage and increased DCs in subjects with Fabry disease.

Confocal microscopy of corneal nerve plexus as an early marker of eye involvement in patients with type 2 diabetes

PurposeTo measure the thickness and length of corneal nerves and the peri-papillary retinal nerve fiber layer (RNFL) thickness in patients recently diagnosed with diabetes mellitus (DM). MethodsTwenty-two eyes of 22 patients recently diagnosed with type 2 DM and 22 eyes of 22 healthy individuals were consecutively enrolled. Central corneal sensitivity was measured using a Cochet-Bonnet esthesiometer, and corneal nerve length (CNL) and thickness (CNT) were evaluated through in vivo confocal microscopy. The confocal images were examined using software that could semi-automatically trace the corneal nerve pathway. Spectral domain optical coherence tomography (SD-OCT) was performed to quantify the overall and sectorial RNFL thickness. ResultsMean DM duration was 3.5 ± 1.7 months, whereas the mean glycemia and HbA1c levels were 180.5 ± 73.13 mg/dl and 8.6 ± 1.7% (65.2 ± 19.7 mmol/mol), respectively. Corneal sensation threshold was significantly lower in the DM group compared to control group (p = 0.003). CNL and CNT were reduced in the DM group (p = 0.043 and p = 0.004, respectively). Significant correlations were found between CNT and HbA1c levels (p = 0.04; r = −0.47), and between CNT and the corneal sensation threshold (p = 0.04; r = 0.69). RNFL thickness was significantly reduced in the temporal quadrants, but no correlation was found with CNT and CNL changes (p > 0.05). ConclusionsCNL and CNT changes are evident even in the early stages of DM, and RNFL reduction was recorded in the temporal quadrants. These findings indicate that, in the eye with diabetes, neuropathy may represent an early marker of the disease.

In Vivo Confocal Microscopic Evaluation of Corneal Nerve Fibers and Dendritic Cells in Patients With Behçet's Disease.

Central and peripheral nervous system involvement may occur during the course of Behçet’s disease (BD). In vivo corneal confocal microscopy (CCM) can detect corneal small fiber damage and immune cell density. The aim of this study was to assess central corneal sensitivity, corneal subepithelial nerve plexus morphology and dendritic cell (DC) density in patients with BD. Forty-nine consecutive patients with BD and 30 healthy control subjects were included in this cross-sectional study conducted at a tertiary referral university hospital. Central corneal sensitivity was measured using the contact corneal esthesiometer (Cochet-Bonnet; Luneau, France). The laser scanning CCM (Heidelberg, Germany) was used to quantify corneal nerve fiber density (NFD), nerve branch density (NBD), nerve fiber length (NFL), and DC density. There was a significant reduction in NFD (P = 0.001) and NFL (P = 0.031) and an increase in DC density (P = 0.038) in patients with BD compared to healthy controls, whereas corneal sensitivity (P = 0.066) and NBD (P = 0.067) did not differ significantly. There was no difference in corneal sensitivity, corneal nerve parameters, or DC density between BD patients with [n = 18 (36.7%)] and without a previous history of uveitis (P > 0.05 for all). Disease duration [median (IQR), 6.5 (4.0–14.5) years] correlated with corneal sensitivity (ρ = −0.463; P = 0.001) and NFD (ρ = −0.304; P = 0.034) and corneal sensitivity correlated with NFD (ρ = 0.411; P = 0.003) and NFL (ρ = 0.295; P = 0.039) in patients with BD. CCM demonstrates corneal sub-basal nerve fiber loss and increased DC density, providing a non-invasive ophthalmic means to identify peripheral neuropathy and inflammation in patients with BD.

Short-Term Effects of Overnight Orthokeratology on Corneal Sub-basal Nerve Plexus Morphology and Corneal Sensitivity.

To assess the effects of a short period of orthokeratology (OK) on corneal sub-basal nerve plexus (SBNP) morphology and corneal sensitivity. Measurements were made in 56 right eyes of 56 subjects with low-to-moderate myopia who wore 2 OK lens designs (Group CRT: HDS 100 Paragon CRT, n=35; Group SF: Seefree; n=21) for a period of 1 month and in 15 right eyes of noncontact lens wearers as controls. The variables determined in each participant were corneal sensitivity using a Cochet-Bonnet esthesiometer and 12 SBNP variables determined on laser scanning confocal microscopy images using 3 different software packages. Correlation between SBNP architecture and corneal sensitivity was also examined. Few changes were observed over the 1-month period in the variables examined in the OK treatment and control groups. However, significant reductions were detected over time in the number of nerves in the central cornea in the groups CRT (P=0.029) and SF (P=0.043) and in central corneal sensitivity in CRT (P=0.047) along with significant increases in central and midperipheral corneal Langerhans cell counts in SF (P=0.001 and 0.048, respectively). This study provides useful data to better understand the anatomical changes induced by OK in corneal SBNP. The different response observed to the 2 OK lens designs requires further investigation.

Long-Term Impacts of Orthokeratology Treatment on Sub-Basal Nerve Plexus and Corneal Sensitivity Responses and Their Reversibility.

To examine the effects of one year of overnight orthokeratology (OK) treatment on the sub-basal nerve plexus (SBNP) and corneal sensitivity and to assess the reversibility of these effects one month after treatment interruption. Thirty-two subjects with low-moderate myopia underwent OK treatment for one year. Fifteen non-contact lens wearers served as controls. At the time points baseline, one year of treatment, and one month after removing the OK lenses, two tests were conducted: corneal sensitivity (Cochet-Bonnet esthesiometer) and SBNP imaging by in vivo confocal microscopy. In participants wearing OK lenses, significant reductions over the year were produced in SBNP nerve density (P=0.001 and P=0.006) and number of nerves (P<0.001 and P=0.001) in the central and mid-peripheral cornea, respectively. Differences over the year were also detected in central objective tortuosity (P=0.002). After lens removal, baseline values of nerve density (P=0.024 and P=0.001) and number of nerves (P=0.021 and P<0.001) for the central and mid-peripheral cornea, respectively, were not recovered. At one month post-treatment, a difference was observed from one-year values in central corneal sensitivity (P=0.045) and mid-peripheral Langerhans cell density (P=0.033), and from baseline in mid-peripheral objective tortuosity (P=0.049). Direct correlation was detected at one year between nerve density and tortuosity both in the central (P<0.01; r=0.69) and mid-peripheral cornea (P<0.01; r=0.76). Long-term OK treatment led to reduced SBNP nerve density and this was directly correlated with corneal tortuosity. After one month of treatment interruption, nerve density was still reduced.

Relationship between corneal biomechanical properties among pregnant women in a tertiary hospital in Nigeria.

In Nigeria, many pregnant women as well as health-care providers are unaware of the effect of pregnancy on the eye. The present study investigated the changes in central corneal thickness (CCT), corneal sensitivity (CS), and intraocular pressure (IOP) among pregnant women in a tertiary hospital in Nigeria and the relationship between them. A prospective longitudinal study was used. One hundred and thirty-four pregnant women attending the Obstetric Clinic of the University of Nigeria Teaching Hospital, Enugu, were consecutively recruited in their second trimester for the study. Changes in CCT, CS, and IOP were monitored at the second and third trimesters and 6-week postpartum. Data obtained were analyzed using Statistical Package for the Social Sciences version 20. The effect of duration of pregnancy on these variables was determined using simple linear regression and further analysis was done using Bonferroni's post hoc test. The women were aged 18-48 years, with a mean age of 30.81(±5.49) years and majority of them (61.2%) were multigravida. The duration of pregnancy varied inversely and significantly with CS (P < 0.05) and IOP (P < 0.000) with the least values recorded in the third trimester, while it varied directly and also significantly with CCT (P < 0.000) with the highest value obtained in the third trimester. A negative correlation that was significant only in third trimester was found between CCT and IOP (P < 0.02) and CS (P < 0.03). There was a progressive increase in CCT with a corresponding decrease in CS and IOP across the trimesters of pregnancy, but these changes reversed 6-week postpartum.

Reduced Corneal Sensitivity and Sub-Basal Nerve Density in Long-Term Orthokeratology Lens Wear.

To investigate changes in corneal sensitivity and nerve morphology in orthokeratology (OK) contact lens wear. In a cross-sectional study, 54 subjects (aged 18-45 years) were grouped into three categories: nonlens (NL), soft lens (SCL), and OK lens wearers. Corneal sensitivity was measured at the corneal apex and 2.5 mm temporal to the apex using the Cochet-Bonnet aesthesiometer. Corneal nerve morphology was assessed by sampling a 1 mm area of the corneal sub-basal nerve plexus using the Heidelberg Retinal Tomograph with Rostock Corneal Module at the corneal apex and 2.5 mm temporal to the apex. Nerve fiber density (NFD) was calculated by measuring the total length of nerve fibers per square millimeter using Image-Pro Analyser. Comparisons between groups were made using mixed analysis of variance and post hoc paired t tests with Bonferroni correction or the Kruskal-Wallis test and post hoc Mann-Whitney U tests as appropriate. There was a significant difference in corneal sensitivity between the three groups (P=0.027). Central threshold was significantly higher in the OK than NL group (0.69±0.42 g/mm vs. 0.45±0.12 g/mm; P=0.048). Mid-peripheral threshold was not different between the three groups (P>0.05). There was a significant difference in NFD between the three groups (P<0.001). Central NFD was significantly less in the OK than NL and SCL groups (OK: 17.89±4.42 mm/mm, NL: 25.87±5.00 mm/mm; SCL: 24.52±4.93 mm/mm; P<0.001). Mid-peripheral NFD was not different between the three groups (P>0.05). Long-term OK lens wear is associated with a decrease in central corneal sensitivity and NFD. The mechanism underlying refractive change during OK treatment seems to impact both corneal sensitivity and nerve morphology.