Basal Epithelial Cell Density Research Articles

Confocal Microscopy of the Cornea in Aqueous-Deficient Dry Eye Disease-A Literature Review.

In vivo confocal microscopy (IVCM) is a vital tool in studying dry eye disease (DED), providing insights into morphological changes at ocular surface unit levels. This review presents the main differences in corneal structure between aqueous-deficient dry eye disease (AD-DED) and normal eyes. A comprehensive search of PubMed, Web of Science, Embase, and MEDLINE databases from January 2000 to December 2023 was conducted. The study selection process, as well as data selection and examination, were independently performed by two members of the review team. The review reveals a consistent decrease in corneal surface epithelial cell density in AD-DED cases compared to a control group, but conflicting data on basal epithelial cell density. Notably, the abnormal hyperreflectivity of keratocytes in patients with Sjogren's syndrome was recorded, and there was a significant keratocyte density in AD-DED subjects compared to evaporative DED and control groups. Studies also found a decrease in sub-basal nerve density, increased tortuosity, and the fragmentation of nerve fibers. Dendritic cell density and dendritic cell dendrites increase in AD-DED patients compared to healthy subjects. IVCM is a powerful tool for enhancing our understanding of the pathophysiological mechanisms underlying DED. However, the review underscores the urgent need to standardize the terminology, analysis, and units used for accurate interpretation, a crucial step in advancing our knowledge of DED.

Evaluation of aqueous-deficient and evaporative dry eye cases with confocal microscopy

Dry eye disease (DED) is an important health problem affecting hundreds of millions of people worldwide. In vivo confocal microscopy (IVCM) is a non-invasive imaging tool that can visualize ocular surface diseases. In this study, we aimed to evaluate corneal structures and inflammatory cells with IVCM in DED patients. The patients were divided into three subgroups: group 1, consisting of 22 patients with aqueous tear insufficiency; group 2, consisting of 21 patients with evaporative type DED; and group 3, consisting of 20 healthy patients. Imaging was performed with IVCM. The corneal epithelium, nerves, stroma, endothelial and inflammatory cells were compared between groups. There was a significant decrease in corneal epithelial cell density in cases with DED, and there was a significant increase in corneal basal epithelial cell density in the aqueous-deficient type. Keratocyte density was significantly increased in the aqueous-deficient type. A significant decrease in the number and density of sub-basal nerves was found in aqueous-deficient cases, and an increase was found in neural pilling and folding. Dendritic cell density, size, number and area were significantly increased in the aqueous-deficient type. There was also decreased corneal endothelial cell density in DED. We evaluated pathological changes in DED on the corneal surface by IVCM. This methodology is valuable in terms of objectively evaluating how the corneal surface is affected in accordance with disease severity and in predicting poor response to treatment.

The diagnosis and treatment of contact lens-induced limbal stem cell deficiency

Objective: To analyze the clinical features and treatment outcomes of eyes with contact lens-induced limbal stem cell deficiency (CL-iLSCD). Methods: This cross-sectional study involved patients diagnosed with CL-iLSCD at the Eye, Ear, Nose & Throat Hospital of Fudan University between October 2018 and September 2022. A total of 17 patients (25 eyes) with a mean age of (36.4±6.9) years were enrolled. Among them, 14 were females (82.4%). Corneal and limbal abnormalities, especially the range of epitheliopathy, were observed under a slit lamp biomicroscope with fluorescein staining. Anterior segment optical coherence tomography and in vivo laser scanning confocal microscopy were performed to obtain the central corneal epithelial thickness, density of basal epithelial cells and corneal nerve fiber length. The clinical features of CL-iLSCD, along with their treatment outcomes and related risk factors, were analyzed. Results: All patients wore soft contact lenses, with an average daily wearing time of (10.5±2.5) hours and a median wearing duration of 10 (4 to 30) years. Ocular symptoms, including decreased vision, ocular discomfort or pain, redness, and photophobia, were present in 22 eyes (88.0%). The most characteristic clinical sign of CL-iLSCD was comb-or whorl-pattern late fluorescein staining under cobalt blue light, which was most commonly seen at the superior limbus (25/25, 100.0%). Additionally, reductions in central corneal epithelial thickness, basal cell density, and corneal nerve fiber length were observed. A comprehensive score was assigned to each eye based on clinical findings and in vivo imaging biomarkers. LSCD was mild, moderate, and severe in 5, 11, and 8 eyes, respectively. A history of misdiagnosis was found in 20 eyes (80.0%). After discontinuing the use of contact lenses and receiving medical treatment, significant improvement was observed in all eyes, with 13 eyes fully recovered. Conclusions: The symptoms and clinical signs of CL-iLSCD can be subtle at the early stage. Discontinuing contact lens wear and medication are effective to treat CL-iLSCD.

The effects of the systemic isotretinoin treatment on ocular surface and meibomian glands: a prospective longitudinal study

Purpose To assess the effects of systemic isotretinoin therapy (SIT) on the ocular surface, meibomian glands (MG) and cornea microstructure in acne vulgaris (AV) patients. Methods Patients with AV (n = 20) and healthy controls (n = 20) were enrolled in the study. All participants underwent ocular surface tests in the order of ocular surface disease index (OSDI) questionnaire, corneal sensitivity, tear break-up time (BUT), fluorescein and lissamine green (LG) staining and Schirmer II test with anaesthesia. MG alterations were evaluated with meibography for upper (UE) and lower eyelids (LE) separately. Corneal basal epithelium and subbasal nerve plexus (SNP) were evaluated using In Vivo Confocal Microscopy (IVCM). Results Schirmer II test with anaesthesia, BUT, corneal sensitivity, fluorescein and LG staining grades and OSDI score results showed no difference between the control group and the baseline of the patient group. Whereas the meibomian gland dysfunction (MGD) grades, UE and LE meiboscores were higher in the patient group at the baseline (p = 0.013, p = 0.004, p = 0.008 respectively). The Control group possessed higher numbers of total and long nerve fibres compared with patients at the baseline (p ≤ 0.001 for both two values). Compared to the baseline and the third month, BUT decreased and fluorescein staining grades increased (p = 0.017 and p = 0.043, respectively). MGD grades, UE and LE meiboscores increased in the third month compared to the baseline (p < 0.001, p < 0.001, p = 0.008 respectively). Basal epithelial cell density (BECD) decreased in the third month of SIT (p = 0.043). Conclusions This prospective study showed that systemic Isotretinoin treatment effects not only ocular surface parameters but also corneal and Meibomian glands structure. Considering early alterations in the course of treatment, ophthalmological assessment and follow-up during SIT are mandatory.

Cell Morphology as an In Vivo Parameter for the Diagnosis of Limbal Stem Cell Deficiency.

The aim of this study was to investigate basal epithelial cell morphology (CM) in the central cornea and limbal areas of eyes with limbal stem cell deficiency (LSCD). This was a prospective, cross-sectional comparative study. We developed a CM scoring system based on basal epithelial cell phenotypes graded from 0 (normal) to 3 (severe morphologic alterations); this system was evaluated by 2 independent masked observers. The CM score was compared with the LSCD clinical score, mean best-corrected visual acuity, and in vivo laser scanning confocal microscopy parameters used to stage LSCD (ie, basal epithelial cell density, basal epithelial thickness, and subbasal corneal nerve fiber length density). One hundred sixty-eight eyes with LSCD and 63 normal eyes were included. Compared with the control group, the LSCD group had significantly higher mean (±SD) CM scores in the central cornea (1.8 ± 0.7 vs. 0.5 ± 0.4, respectively; P = 0.01) and limbal areas (1.6 ± 0.2 vs. 1.3 ± 0.0, respectively; P < 0.05). The mean CM score in the central cornea was positively correlated with the clinical score ( P < 0.01, r = 0.66) and negatively correlated with the best-corrected visual acuity ( P < 0.01, r = 0.42). The CM scores were positively correlated with all other in vivo laser scanning confocal microscopy parameters in the central cornea and limbal areas (all P < 0.001). Basal epithelial CM is altered in the central cornea and limbus of eyes with LSCD and thus can be used to stage the clinical severity of the disease.

Age-related differences in corneal nerve regeneration after SMILE and the mechanism revealed by metabolomics

PurposeTo investigate the effect of age on wound healing after small incision lenticule extraction (SMILE) and the underlying metabolomic mechanisms. MethodsThis prospective study was conducted on 216 patients in four groups: the 18–20 (n = 38, Group I), 21–30 (n = 84, Group Ⅱ), 31–40 (n = 58, Group Ⅲ), and 41–50 (n = 36, Group IV) age groups. The density of corneal epithelial wing cells, basal cells, corneal stromal cells, endothelial cells and corneal nerves were examined with a laser confocal microscope (HRT III-RCM) before and 1 month, 3 month, 6 month and 1 year after SMILE. The central nerve fiber length (CNFL), the central corneal nerve fibre density (CNFD), and the central corneal nerve branch density (CNBD) were analyzed by Nero J. The corneal stroma lenticules were obtained from SMILE to analyze metabolites by high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS). ResultsThe density of corneal wing epithelial cells and basal epithelial cells have no significant difference among the four groups. The CNFL was 21.90 ± 1.68 mm/mm2 in Group Ⅰ and 21.63 ± 2.09 mm/mm2 in Group Ⅱ after 1 year of SMILE, which represented a return to the preoperative level, whereas the CNFL of Group Ⅲ (19.40 ± 0.98 mm/mm2) and Group Ⅳ (18.94 ± 0.72 mm/mm2) were lower than that preoperation (P ˂0.01). CNFL repair had a negative correlation with age after surgery (Pearson's R = −0.572, P ˂0.01). The CNFD and the CNBD showed the same trend with the CNFL (Pearson's R = −0.602 and −0.531, P ˂0.05). Through screening the significantly different metabolites between the 18–30 age group (including Group I and Group Ⅱ) and other two groups, 6 common remarkably different metabolites were identified. Meanwhile, 5 unique different metabolites were identified only between the 18–30 age group and the 31–40 age group. Six unique different metabolites were identified only between the 18–30 age group and the 41–50 age group. ConclusionCorneal nerve repair after SMILE was significantly affected by age. The identified age-associated differences in metabolites were mainly related to inflammation, oxidation, nerve protection and regeneration.

Bilateral Limbal Stem Cell Alterations in Patients With Unilateral Herpes Simplex Keratitis and Herpes Zoster Ophthalmicus as Shown by In Vivo Confocal Microscopy.

PurposeThe purpose of this study was to investigate the limbal changes in the palisades of Vogt (POV) in patients with herpes simplex keratitis (HSK) and herpes zoster ophthalmicus (HZO) with the application of in vivo confocal microscopy (IVCM).MethodsWe enrolled 35 eyes of 35 consecutive patients with HSK and 4 patients with HZO in this observational study. Thirty-five participants were also recruited from a healthy population as the control group. All subjects were examined by IVCM in addition to routine slit-lamp biomicroscopy. The IVCM images of the corneal basal epithelial cells, corneal nerve, and the corneoscleral limbus were acquired and then were analyzed semiquantitatively.ResultsThe rate of absent and atypical POV was significantly higher in the affected eyes of patients with HSK than in the contralateral eyes and eyes of controls (88.57% vs. 65.71% vs. 17.14%, P < 0.01). In the HZO group, the rate of absent and atypical POV was 100% in the affected eyes and 50% in the contralateral eyes. When compared to the contralateral unaffected eyes and control eyes, the average density of the central basal epithelial cells and the sub-basal nerve plexus density and the total number of nerves in the central area of the affected eyes were significantly lower in the HSK group (1541 ± 704.4 vs. 2510 ± 746.8 vs. 3650 ± 746.1 cells/mm2, P < 0.0001). Spearman's rank correlation showed that the presence of absent and atypical POV had a significant negative correlation with central corneal basal epithelial cells (rs = −0.44979, P < 0.0001), the density of total nerves (rs = −0.49742, P < 0.0001), and the total nerve numbers (rs = −0.48437, P < 0.0001). A significant positive correlation was established between the presence of absent and atypical POV and HSK severity in affected eyes in the superior, inferior, nasal, and temporal quadrants (rs = 0.68940, rs = 0.78715, rs = 0.65591, and rs = 0.75481, respectively, P < 0.0001) and the contralateral eyes (rs = 0.51636, rs = 0.36207, rs = 0.36990, rs = 0.51241, correspondingly, P < 0.0001).ConclusionsBoth eyes of patients with unilateral HSK and HZO demonstrated a profound and significant loss of limbal stem cells, which may explain the fact that HSK and HZO are risk factors for limbal stem cell deficiency (LSCD) in both eyes. The loss of LSCs was strongly correlated with the sub-basal nerve plexus and central basal epithelial cell alterations as shown by IVCM.

Femtosecond laser-assisted cataract surgery in eyes with shallow anterior chamber depth: comparison with conventional phacoemulsification.

To compare the postoperative outcomes between femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification in eyes with shallow anterior chamber depth (ACD). Eye Clinic, NEUROFARBA Department, University of Florence, Italy. Prospective case series. Forty eyes of 40 patients with senile cataract and true ACD less than 2.00 mm underwent FLACS (femto group, n = 20) or manual phacoemulsification (phacoemulsification group, n = 20). Preoperatively and 1 week and 1 month and 6 months postoperatively, central corneal thickness (CCT) and endothelial cell density were evaluated; basal epithelial cell (BEC) and Langerhans dendritic cell (LDC) densities and keratocyte activation were assessed using in vivo corneal confocal microscopy. Intraoperative parameters such as cumulative dissipated energy (CDE) and ultrasound (US) power were recorded. Endothelial cell loss (ECL) was significantly lower in the femto group at all timepoints (P ≤ .001). In the phacoemulsification group, the CCT was significantly higher 1 week (P < .001) and 1 month (P < .001) postoperatively than preoperatively; conversely, in the femto group, it was higher only after 1 week (P < .001). BECs and LDCs significantly increased at 1 postoperative week (P < .001), returning to preoperative values after 1 month in both groups. Keratocyte activation remained significantly higher at 1 postoperative month only in the phacoemulsification group (P = .005). CDE and US power were lower in the femto group (P = .017 and P = .001, respectively); they were correlated with ECL (r = 0.662, P = .000; r = 0.389, P = .013). In eyes with shallow ACD, FLACS was a safe and an effective technique, significantly reducing the postoperative ECL and corneal inflammation compared with conventional phacoemulsification.

In Vivo Confocal Microscopy Observation of Cell and Nerve Density in Different Corneal Regions with Monocular Pterygium.

Purpose To investigate the effects of pterygium on corneal cell and nerve density in patients with unilateral pterygium using in vivo laser scanning confocal microscopy (LSCM). Methods In this cross-sectional study, 24 patients with unilateral pterygium who were treated in the Department of Ophthalmology of the Second People's Hospital of Wuxi City from April 2018 to July 2018 were analyzed. Each eye with pterygium and its fellow eye were imaged by LSCM. The density of basal corneal epithelial cells, anterior stromal cells, posterior stromal cells, dendritic cells, and endothelial cells in pterygium and adjacent clear cornea was measured. In the fellow eyes, the central cornea, nasal cornea, nasal mid-peripheral cornea, and temporal cornea were imaged. The difference in the density of cells and subepithelial nerve fibers in different corneal regions of eyes with pterygium was analyzed. The cell and nerve density of the fellow cornea were also measured to exclude the influencing factors. Results The density of corneal basal epithelial cells in the central corneas of eyes with pterygium was 6497 ± 1776 cells/mm2, which was higher than that in the area near the head of pterygium (5580 ± 1294 cells/mm2, P < 0.001), the region above pterygium (6097 ± 1281 cells/mm2, P=0.049), and the region below pterygium (5463 ± 1007 cells/mm2, P=0.001). The density of anterior stromal cells in the central cornea was 742 ± 243 cells/mm2, which was higher than that in the area near the head of pterygium (587 ± 189 cells/mm2, P=0.005), the region below pterygium (492 ± 159 cells/mm2, P=0.005), and the temporal cornea (574 ± 164 cells/mm2, P=0.003). The density of endothelial cells in the central cornea was 2398 ± 260 cells/mm2, which was higher than that in the area near the head of pterygium (2296 ± 231 cells/mm2, P=0.011) and the region below pterygium (2272 ± 400 cells/mm2, P=0.020). The density of dendritic cells in the central cornea was 53 ± 48 cells/mm2, which was lower than that in the area near the head of pterygium (250 ± 224 cells/mm2, P=0.001), the upper region (103 ± 47 cells/mm2, P=0.006), and the lower region (90 ± 48 cells/mm2, P=0.023). The corneal nerve fiber length (CNFL) in the center was higher than that in the area near the head of pterygium, the upper region, and the lower region. Compared with fellow eyes, eyes with pterygium had a significantly higher mean corneal power (KM) (P < 0.001). There was a significant positive linear relationship between the corneal area invaded by pterygium of pterygia and KM (r = 0.609, P=0.009). Conclusion Basal epithelial cells, stromal cells, endothelial cells, dendritic cells, and subepithelial nerve fibers in the central cornea of eyes with pterygium were different from those of pterygium and adjacent clear cornea. LSCM is effective for observing the morphology and quantity of corneal cells in pterygium.

Limbal Stem Cell Deficiency After Glaucoma Surgery.

To characterize the clinical presentation of limbal stem cell deficiency (LSCD) associated with glaucoma surgeries. This is a retrospective cross-sectional study of patients with LSCD and glaucoma who presented to the Stein Eye Institute at the University of California, Los Angeles, between 2009 and 2018. Patients who underwent trabeculectomy and/or aqueous shunt surgery were included. The severity of LSCD was staged using global consensus guidelines and a clinical scoring system, and basal epithelial cell density was measured by in vivo confocal microscopy. Anatomic locations of glaucoma and non-glaucoma surgeries, locations of LSCD, and severity of LSCD were compared. Fifty-one eyes of 41 patients with LSCD associated with glaucoma surgery were included in this study. LSCD in these patients uniquely featured sectoral replacement of corneal epithelium by conjunctival epithelium, without corneal neovascularization or pannus. The sites of glaucoma surgery strongly correlated with the locations of LSCD (P = 0.002). There was a trend toward increased severity of LSCD in eyes with 2 or more glaucoma surgeries as compared to eyes with 1 glaucoma surgery, although the difference did not reach statistical significance (P = 0.3). Use of topical glaucoma medications correlated with LSCD severity, while the impact of antimetabolites did not reach statistical significance. The location of glaucoma drainage surgery is correlated with the location of LSCD. LSCD associated with glaucoma surgery has clinical features distinct from LSCD resulting from other etiologies. Further study is required to delineate the full impact of glaucoma surgery on limbal stem cell function and survival.

Ocular Surface, Meibomian Gland Alterations, and In Vivo Confocal Microscopy Characteristics of Corneas in Chronic Cigarette Smokers.

To evaluate the ocular surface, meibomian gland alterations, and in vivo confocal microscopy (IVCM) parameters through correlation with nicotine dependency level (NDL) and duration of smoking (DS) in chronic smokers. This cross-sectional study included 50 eyes of 50 chronic smokers, and 50 eyes of 50 age- and gender-matched healthy nonsmokers. To examine the ocular surface and tear film, corneal sensitivity (CS) measurement with Cochet-Bonnet esthesiometer, tear film break-up time (TBUT), lissamine green (LG) staining, Schirmer I test with anesthesia, and Ocular Surface Disease Index (OSDI) questionnaire were performed consecutively. Basal epithelial cell, keratocyte, and endothelial cell density, the percentage of endothelial polymegethism/pleomorphism, and subbasal nerve plexus were evaluated using IVCM. Meibomian gland density was evaluated with a meibography unit. The Fagerström test was used to measure NDL, and DS was recorded. In the chronic smokers group, the basal epithelial cell density, anterior and posterior keratocytes, endothelial cell density, and long and total subbasal nerve numbers were lower, and LG staining, meiboscore, and OSDI scores were higher, compared with the control group, whereas other parameters were similar. The percentage of polymegethism was higher and the percentage of pleomorphism was lower in the chronic smokers group. In the correlation analysis, no significant relationship was found between the DS, NDL and ocular surface, and IVCM findings. Decreased corneal basal epithelium, anterior and posterior keratocytes, endothelial cell density, meibomian gland density, and subbasal nerve numbers were found in chronic smokers. The results of the study show that smoking has an adverse effect on ocular surface parameters.

Triphasic polymeric corneal coating gel versus a balanced salt solution irrigation during cataract surgery: A postoperative anterior segment optical coherence tomography analysis and confocal microscopy evaluation

To investigate the safety and efficacy of the intraoperative use of a triphasic polymeric gel as corneal coating during cataract surgery and its effect on postoperative ocular comfort. Eye Clinic, University of Florence, Italy. Longitudinal observational retrospective study. Data on patients who received an application of a polysaccharide blend of hydroxypropyl methylcellulose, xanthan gum, and carrageenan (EyeDRO) on the corneal surface and data on patients who received a balanced salt solution during phacoemulsification surgery were analyzed. The central corneal thickness (CCT) and epithelial thickness were examined using anterior segment optical coherence tomography, and the corneal basal epithelial cell (BEC) and Langerhans cell densities by invivo confocal microscopy. The ocular surface disease index (OSDI) score, tear breakup time (TBUT), and Schirmer test I values were evaluated. The study comprised data on 28 patients in the coating gel group and 26 patients in the balanced salt solution group. In the coating gel group, the CCT and epithelial thickness values returned to the baseline value within 5 and 15 postoperative days, respectively; the BEC and Langerhans cell densities returned to baseline levels within 15 and 30 postoperative days. In the balanced salt solution group, the mean BEC and Langerhans cell densities were significantly different from the preoperative values at all follow-up assessments. The TBUT returned to the preoperative level at day 5 in the coating gel group. The OSDI scores returned to the preoperative values after 15days in the coating gel group and 30days in the balanced salt solution group. The use of a tripolymeric gel as a corneal coating during cataract surgery played a protective role on the corneal surface and reduced postoperative discomfort symptoms.

Effect of diabetes mellitus type 1 diagnosis on the corneal cell densities and nerve fibers.

Relation of diabetes mellitus (DM) to the various stages of corneal nerve fiber damage is well accepted. A possible association between changes in the cornea of diabetic patients and diabetic retinopathy (DR), DM duration, and age at the time of DM diagnosis were evaluated. The study included 60 patients with DM type 1 (DM1) and 20 healthy control subjects. The density of basal epithelial cells, keratocytes and endothelial cells, and the status of the subbasal nerve fibers were evaluated using in vivo corneal confocal microscopy. Basal epithelial cell density increased with age (p=0.026), while stromal and endothelial cell density decreased with age (p=0.003, p=0.0005, p<0.0001). After the DM1 diagnosis was established, this association with age weaken. We showed nerve fiber damage in DM1 patients (p<0.0001). The damage correlated with the degree of DR. DM1 patients with higher age at DM1 diagnosis had a higher nerve fiber density (p=0.0021). These results indicated that age at DM1 diagnosis potentially has an important effect on final nerve fiber and corneal cell density.

Ocular surface adverse events of systemic epidermal growth factor receptor inhibitors (EGFRi): A prospective trial

Controversy exists regarding the safety of agents that systemically inhibit epidermal growth factor receptor (EGFRi) in oncologic patients in terms of toxicity to the ocular surface. We performed a prospective clinical study comparing the ocular surface toxicity of systemic EGFRi between a case and a control group. Patients with lung or colon cancer were divided in two groups: 25 patients treated with systemic EGFRi and 25 control patients without EGFRi treatment. Patients in both groups were chemotherapy naive. Four visits were scheduled in a one year period comparing signs and symptoms in terms of symptom questionnaires (SIDEQ, OSDI and AVS), corneal fluorescein staining (Oxford test), tear production (Schirmer's test) and a quantitative evaluation of conjunctival chemosis and hyperemia. Basal epithelial cell density (CEBD) and corneal subepithelial nerve fiber density (CNFD) were measured and compared using confocal microscopy (Heidelberg Engineering, Germany). The differences in each variable were compared with the analysis of variance (ANOVA). A P value<0.05 was considered significant for all comparisons. No statistically significant differences were found between patients under EGFRi treatment and the age-matched controls in the variables analyzed. When cases and controls were evaluated separately, the case group showed a significantly worse progression of signs (chemosis score, CFS, Schirmer's) as well as in terms of CEBD and CNFD (all P<0.05). Systemic EGFRi may increase dry eye signs as well as decrease CEBD and CNFD. This study may help us to understand the true toxicity of EGFRi to the ocular surface.

Classification of Limbal Stem Cell Deficiency Using Clinical and Confocal Grading

To grade the severity of limbal stem cell deficiency (LSCD) based on the extent of clinical presentation and central corneal basal epithelial cell density (BCD). This is a retrospective observational comparative study of 48 eyes of 35 patients with LSCD and 9 eyes of 7 normal subjects (controls). Confocal images of the central cornea were acquired. A clinical scoring system was created based on the extent of limbal and corneal surface involvement. LSCD was graded as mild, moderate, and severe stages based on the clinical scores. The degree of BCD reduction was given a score of 0 to 3. Compared with BCD in controls, BCD decreased by 23.0%, 40.4%, and 69.5% in the mild, moderate, and severe stages of LSCD classified by the clinical scoring system, respectively. The degree of BCD reduction was positively correlated with larger limbal and corneal surface involvement and when the central visual axis was affected (all P ≤ 0.0005). Mean corrected distance visual acuity logarithm of the minimum angle of resolution was 0.0 ± 0.0 in control eyes, 0.2 ± 0.5 in mild LSCD, 0.6 ± 0.4 in moderate LSCD, and 1.6 ± 1.1 in severe LSCD (P < 0.0001). There was a significant correlation between a higher clinical score and corrected distance visual acuity logarithm of the minimum angle of resolution (rho = 0.82; P < 0.0001) and a greater decrease in BCD (rho = -0.78; P < 0.0001). A clinical scoring system was developed to assess the extent of clinical presentation of LSCD. A classification system to grade the severity of LSCD can be established by combining the BCD score with the clinical score.

Epithelial changes with corneal punctate epitheliopathy in type 2 diabetes mellitus and their correlation with time to healing

BackgroundTo study basal epithelial cell (BEC), sub-basal nerve plexus (SBN) and Langerhans cell (LC) density in patients with type 2 diabetes mellitus (T2DM) with corneal punctate epitheliopathy (CPE) and to assess their association with time to healing of CPE.MethodsRetrospective study of in vivo confocal microscopy (IVCM) in 160 eyes from 160 patients with T2DM diagnosed with CPE due to a single cause. Key exclusion criteria included multiple-causes for CPE or treatment with autologous serum. A total of 149 eyes from 149 gender- age- and aetiolgy-matched patients with CPE without T2DM comprised the control group. Electronic records were reviewed for demographic features, history of T2DM and aetiology of CPE. Density of BEC, SBN and LC were compared between the two groups.ResultsThe healing time in days for CPE with different aetiologies in the T2DM and control groups were as follows: dry eye (21.56 ± 2.41; 7.00 ± 2.19; P = 0.001); meibomian gland dysfunction (26.42 ± 6.04; 9.21 ± 2.55; P = 0.001); cataract extraction (38.00 ± 19.62; 25.83 ± 11.49; P = 0.043); drug induced (53.19 ± 18.83; 41.86 ± 23.87; P = 0.018) and exposure (38.25 ± 14.13; 29.00 ± 13.67; P = 0.026). LC density was 38.70 ± 9.65 cells/mm2 in the T2DM group comparedwith 25.53 ± 3.54 cells/mm2 in the controls (P = 0.001). SBN density was 11.76 ± 1.69 mm/mm2 in the T2DM group compared with 20.92 ± 1.43 mm/mm2 in the controls (P = 0.001). BEC density in the T2DM group was 4982 ± 1178 cells/mm2 compared with 5739 ± 394 cells/mm2 in the control group (P = 0.018). Age and duration of T2DM had no relationship with healing time (multiple linear regression, P = 0.618; P = 0.787). The density of LC in the T2DM group showed a negative correlation with SBN density (r = 0.350; R2 = 0.1225; P = 0.034). The density of SBN in the T2DM group showed a positive correlation with BEC density (r = 0.427; R2 = 0.1823; P = 0.008). The density of BEC in the T2DM group showed a negative correlation with healing time (r = 0.931; R2 = 0.8668; P = 0.001).ConclusionsUtilising IVCM, we have demonstrated increased LC and decreased SBN in patients with T2DM and CPE. Both may be related to lower BEC density and nuclei enhanced reflection. Furthermore, decreased BEC density may lead to delay in cornea epithelium healing in the T2DM group comparedwith controls. An immune-mediated response may play a role in delayed wound closure in patients with T2DM.

Tear Levels of Insulin-Like Growth Factor Binding Protein 3 Correlate With Subbasal Nerve Plexus Changes in Patients With Type 2 Diabetes Mellitus.

PurposeThis study investigated the expression of insulin-like growth factor binding protein-3 (IGFBP-3) in basal tears of patients with type 2 diabetes mellitus compared to nondiabetic controls; and correlated tear levels of IGFBP-3 with morphologic changes in the subbasal nerve plexus and density of basal corneal epithelial cells.MethodsThis was a single visit, cross-sectional study. Diabetic and control subjects were matched for age, sex, smoking status, and body mass index. Tear levels of IGFBP-3 were measured using ELISA. Corneal nerve and basal epithelial cell changes were measured using in vivo confocal microscopy.ResultsTear levels of IGFBP-3 were 3.5-fold higher in those with diabetes. Patients with diabetes also showed a reduction in nerve fiber layer, nerve branch density, and corneal basal epithelial cell density. There was no significant difference in corneal sensitivity. IGFBP-3 levels were highly correlated with nerve fiber length and branch density; while hemoglobin (Hb)A1c was only moderately correlated. There were no significant differences in the clinical or subjective signs of dry eye between groups, indicating that tear levels of IGFBP-3 and corneal nerve changes were not due to the presence of mild dry eye.ConclusionsThese findings indicate that tear levels of IGFBP-3 are more tightly correlated to nerve fiber changes in diabetes than HbA1c. Future studies that stratify the severity of diabetic disease with tear levels of IGFBP-3 are needed to validate this finding.

Ocular Surface Alterations in the Context of Corneal In Vivo Confocal Microscopic Characteristics in Patients With Fibromyalgia.

To quantify the morphology of corneal basal epithelium and subbasal nerves and to evaluate the ocular surface alterations in patients with fibromyalgia (FM). Patients with FM (n = 34) and healthy controls (n = 42) were enrolled. All participants underwent ocular surface tests in the following order: corneal sensitivity, tear film breakup time, lissamine green staining, Schirmer test, and the Ocular Surface Disease Index questionnaire. Basal epithelial cells and subbasal nerves were evaluated using in vivo confocal microscopy (IVCM). Demographic characteristics, Visual Analog Scale for Pain (VAS), American College of Rheumatology 1990, the Widespread Pain Index (WPI), and the Symptom Impact Questionnaire (SIQR) scores of patients with FM were obtained. Corneal sensitivity was 0.4 g/mm (fiber length: 6.0 cm) in all eyes. Patients with FM had a higher Ocular Surface Disease Index (42.2 ± 18.9 vs. 1.2 ± 1.7, P < 0.001), higher lissamine green staining scores (0.5 ± 0.5 vs. 0.05 ± 0.2, P < 0.001), and lower tear breakup time scores (9.0 ± 3.6 vs. 10.3 ± 1.5, P = 0.003) than the controls. Basal epithelial cell density (2709 ± 494 vs. 4491 ± 724), total nerve density (1563 ± 620 vs. 2545 ± 973), long nerve fibers (3.4 ± 1.3 vs. 4.5 ± 1.0), and the number of nerves (5.0 ± 1.8 vs. 10.3 ± 2.1) were all lower in patients with FM compared with those of the controls (P < 0.001 for all). There was a statistically significant negative correlation between the WPI score and Schirmer test results (rho = -0.374, P = 0.03) and between WPI and total nerve density (rho = -0.334, P = 0.054). To the best of our knowledge, this is the first study that evaluated ocular surface alterations in the context of corneal IVCM characteristics. Patients with FM should be evaluated in terms of ocular surface diseases. IVCM may be used in FM to assess small fiber neuropathy.

Early central and peripheral corneal microstructural changes in type 2 diabetes mellitus patients identified using in vivo confocal microscopy: A case-control study.

The aim of this study was to find early central and peripheral corneal microstructural changes in healthy subjects and type 2 diabetes mellitus (T2DM) patients with/without cornea fluorescein dot staining.This is a prospective case-control study of T2DM patients with/without cornea fluorescein dot staining. Age, sex, duration of diabetes, and serum glycosylated hemoglobin A1c (HbA1c) levels were recorded. Keratograph 5 M (K5 M) and in vivo confocal microscopy were performed on all subjects. The cornea was divided into 5 zones: central, superior, temporal, nasal, and inferior. Basal epithelial cell (BEC) density, the area of BEC, sub-basal nerve plexus (SBN) density, Langerhans cell (LC), and endothelial cell (EC) density were quantitatively analyzed.This study included a total of 87 individuals (28 males and 59 females; mean age, 62.30 ± 9.93 years) with T2DM, without (n = 48; T2DM group 1) and with (n = 39; T2DM group 2) cornea fluorescein staining, as well as 51 age- and sex-matched healthy subjects (18 males and 33 females; mean age, 61.53 ± 10.15 years). Ocular Surface Disease Index scores, Schirmer Ι test, tear meniscus height, the first breakup of tear film occurrence (NIKBUT-first), and the average time of all breakup incidents (NIKBUT-average) values were significantly lower for the T2DM groups than for the healthy group. The corneal sensations of all cornea positions in the T2DM groups were significantly different from the control group. The HbA1c in the T2DM groups showed a negative correlation with central BEC density (R = 0.348, P = .015; R = 0.91, P = .001); there was no correlation of HbA1c with BEC density in the control group. The BEC density, the area of BEC, SBN, and LC density of T2DM group 1 and T2DM group 2 were significantly different compared with the control group in all corneal positions (P < .001). The BEC density of T2DM group 2 was significantly different from T2DM group 1 in the central (P = .044) and inferior (P = .013) zones. The area of BEC in T2DM group 2 was significantly different from T2DM group 1 in inferior zone (P = .014) and other corneal positions showed was no significant difference (P > .05). The SBN density of T2DM group 2 was not significantly different from T2DM group 1 in all corneal positions (P > .05). The LC density of T2DM group 2 was significantly different from T2DM group 1 in the central (P = .006) and inferior (P = .006) zones. Although the LC density in the T2DM groups showed no significant difference in all corneal zones (P > .05), the LC density in the central zone was significantly lower compared with the peripheral zone in the control group (P = .001). The central ECs in the 3 groups were not significantly different (P > .05).LC induced an immune-mediated contribution to corneal nerve damage and may influence the early stages of BEC proliferation and differentiation in T2DM. BEC density was the reliable index for evaluating the early condition of diabetic corneal epitheliopathy. The BEC density of the central and inferior corneal zones was more sensitive.

Contact Lenses for Keratoconus- Current Practice.

Background:Keratoconus is a chronic, bilateral, usuallly asymmetrical, non-inflammatory, ectatic disorder, being characterized by progressive steepening, thinning and apical scarring of the cornea. Initially, the patient is asymptomatic, but the visual acuity gradually decreases, resulting in significant vision loss due to the development of irregular astigmatism, myopia, corneal thinning and scarring. The classic treatment of visual rehabilitation in keratoconus is based on spectacles and contact lenses (CLs).Objective:To summarize the types of CLs used in the treatment of keratoconus. This is literature review of several important published articles focusing on the visual rehabilitation in keratoconus with CLs.Method:Gas permeable (GP) CLs have been found to achieve better best corrected visual acuity than spectacles, eliminating 3rd-order coma root-mean-square (RMS) error, 3rd-order RMS, and higher-order RMS. However, they have implicated in reduction of corneal basal epithelial cell and anterior stromal keratocyte densities. Soft CLs seem to provide greater comfort and lower cost, but the low oxygen permeability (if the lens is not a silicone hydrogel), and the inability to mask moderate to severe irregular astigmatism are the main disadvantages of them. On the other hand, scleral CLs ensure stable platforms, which eliminate high-order aberrations and provide good centration and visual acuity. Their main disadvantages include the difficulties in application and removal of these lenses along with corneal flattening and swelling.Result:The modern hybrid CLs are indicated in cases of poor centration, poor stability or intolerance with GP lenses. Finally, piggyback CL systems effectively ameliorate visual acuity, but they have been related to corneal neovascularization and giant papillary conjunctivitis.Conclusion:CLs seem to rehabilitate visual performance, diminishing the power of the cylinder and the high-order aberrations. The final choice of CLs is based on their special features, the subsequent corneal changes and the patient’s needs.