Basal Epithelial Cell Density Research Articles

Using corneal confocal microscopy to track changes in the corneal layers of dry eye patients after autologous serum treatment

BackroundIn vivo corneal confocal microscopy allows the examination of each layer of the cornea in detail and the identification of pathological changes at the cellular level. The purpose of this study was to identify the possible effects of a three‐month treatment with autologous serum eye‐drops in different corneal layers of patients with severe dry eye disease using corneal confocal microscopy.MethodsTwenty‐six patients with dry eye disease were included in the study. Corneal fluorescein staining was performed. The corneas of the right eyes were examined using in vivo corneal confocal microscopy before and after a three‐month treatment with autologous serum drops. The densities of superficial and basal epithelial cells, Langerhans cells, the keratocytes and activated keratocytes, the density of endothelial cells and the status of the sub‐basal nerve plexus fibres were evaluated.ResultsA significant decrease in corneal fluorescein staining was found after the three‐month autologous serum treatment (p = 0.0006). The basal epithelial cell density decreased significantly (p = 0.001), while the density of superficial epithelial cells did not change significantly (p = 0.473) nor did the number of Langerhans cells or activated keratocytes (p = 0.223; p = 0.307, respectively). There were no differences in the other corneal cell layers or in the status of the nerve fibres.ConclusionsThe results demonstrate the ability of corneal confocal microscopy to evaluate an improvement in the basal epithelial cell layer of the cornea after autologous serum treatment in patients with dry eye disease. More studies with longer follow‐up periods are needed to elucidate the suitability of corneal confocal microscopy to follow the effect of autologous serum treatment on nerve fibres or other corneal layers in dry eye disease patients.

Omega-3 supplementation is neuroprotective to corneal nerves in dry eye disease: a pilot study.

To investigate whether oral, long-chain omega-3 (ω-3) essential fatty acid (EFA) supplementation, for 3 months, induces changes to the central corneal sub-basal nerve plexus in dry eye disease and whether nerve alterations correlate with clinical findings. This prospective, comparative study involved the final 12 participants enrolled in a randomised, double-masked, placebo-controlled clinical trial of 60 participants with moderate dry eye disease. Participants received either placebo (olive oil 1500 mg/day; n = 4) or ω-3 EFA supplements (~1000 mg/day eicosapentaenoic acid + ~500 mg/day docosahexaenoic acid; n = 8) for 90 days. The main outcome measure was the mean change in central corneal sub-basal plexus nerve parameters between days one and 90, quantified using in vivo confocal microscopy. Secondary outcomes included mean change in tear osmolarity, corneal dendritic cell density and basal epithelial cell density. Compared with baseline, the reduction in OSDI score and tear osmolarity at day 90 were greater in the ω-3 EFA group than the placebo group (OSDI: ω-3 EFA, mean ± SEM: -15.6 ± 2.8 vs placebo: -2.8 ± 4.1 units, t5 = 2.6, p = 0.04; tearosmolarity: ω-3 EFA: -22.63 ± 5.7 vs placebo: -8 ± 2.7 mOsmol/L, t9 = 2.3, p = 0.04). At day 90, corneal total nerve branch density (CTBD: 91.1 ± 8.6 vs 45.1 ± 13.4 branches/mm2 , F1,10 = 14, p = 0.004) and corneal nerve branch density on the main fibre (CNBD: 63.4 ± 6.5 vs 27.9 ± 11.5 branches/mm2 , F1,10 = 6, p = 0.03) were higher in the ω-3 EFA group compared with placebo. Relative to day 1, CNBD (branches/mm2 ) increased at day 90 in the ω-3 EFA group (+20.0 ± 9.2, t8 = 3.2 p = 0.01) compared with placebo (-10.8 ± 3.2). Similar changes were evident for corneal nerve fibre length (CNFL, mm/mm2 ), which increased from baseline at day 90 in the omega-3 EFA group (+2.9 ± 1.6, t8 = 3.4 p = 0.01) compared with placebo (-2.7 ± 0.5). There was a negative correlation between CTBD and tear osmolarity (r10 = -0.70, p = 0.01). No significant changes were observed for basal epithelial cell or corneal dendritic cell density. These pilot study findings suggest that ω-3 EFA supplementation imparts neuroprotective effects in the corneal sub-basal plexus that correlate with the extent of tear osmolarity normalisation.

The impact of lens care solutions on corneal epithelial changes during daily silicone hydrogel contact lens wear as measured by in vivo confocal microscopy.

To assess corneal epithelial microstructure via confocal microscopy and determine if cellular changes are associated with lens care solutions during daily wear of silicone hydrogel contact lenses. Corneal in vivo confocal microscopy with the Nidek ConfoScan4 was performed at baseline and after 5 months of lotrafilcon A daily contact lens wear. Enrolled participants were randomized to use either a polyhexamethylene biguanide (PHMB) preserved multipurpose care solution (MPS) or a peroxide based solution system. Lens and storage case bioburden were assessed with aerobic culture methods. Univariate and multivariable analyses were done to evaluate the association between solution use, or solution-related clinical covariates, and morphologic differences (hyper-reflectivity) in the superficial epithelial cells and epithelial basal cell density. Data on 139 participants were available for analysis of superficial epithelial cells while data on 92 participants were available for epithelial basal cell density. Five months after randomization to the solution groups, 33% of participants had visible hyper-reflective cells. More participants using MPS had ≥1 hyper-reflective cells compared to peroxide users at 5 months (44% vs. 22%; p=0.006). Similarly at 5 months, more participants with solution-induced corneal staining (SICS) had ≥1 hyper-reflective cells compared to non-SICS participants (57% vs. 29%; p=0.010). The adjusted odds ratios (ORs) for risk of presenting with hyper-reflective cells in MPS users or SICS participants was 2.7 (95% CI; 1.27-5.65) and 3.4 (95% CI; 1.29-8.97), respectively. Basal cell density decreased by over 350 cells/mm2 over time (about 6%) in participants who had substantial bioburden on their lenses or in their storage case. The confocal microscope can detect epithelial cellular changes in vivo during contact lens wear. Hyper-reflective superficial epithelial cells are associated with a PHMB preserved solution and decreases in basal epithelial cell density may be associated with bacterial bioburden.

Corneal Nerve and Epithelial Cell Alterations in Corneal Allodynia: An In Vivo Confocal Microscopy Case Series

PurposeTo investigate morphological changes of the corneal epithelium and subbasal nerves in patients with corneal allodynia using in vivo confocal microscopy (IVCM). DesignCase-control study of patients with corneal allodynia and healthy controls. MethodsTen eyes of six patients were diagnosed with corneal allodynia at a single center and compared to fifteen healthy eyes. IVCM of the central cornea was performed on all subjects and controls. Images were retrospectively analyzed numbers of total corneal subbasal nerves, main trunks and branches, total nerve length and density, nerve branching, and tortuosity, superficial and basal epithelial cell densities, and superficial epithelial cell size. ResultsCorneal allodynia was seen in patients with dry eye disease, recurrent corneal erosion syndrome, exposure to ultraviolet radiation, and Accutane use. Compared to controls, patients with corneal allodynia had a significant decrease in the total numbers of subbasal nerves (P=.014), nerve branches (P=.006), total nerve length (P=.0029), total nerve density (P=.0029) and superficial and basal epithelial cell densities (P=.0004, P=.0036) with an increase in superficial epithelial cell size (P=.016). There were no statistically significant differences in the number of subbasal nerve main trunks (P=.09), nerve branching (P=.21), and nerve tortuosity (P=.05). ConclusionsCorneal IVCM enables near-histological visualization and quantification of the cellular and neural changes in corneal allodynia. Regardless of etiology, corneal allodynia is associated with decreased corneal epithelial cell densities, increased epithelial cell size, and decreased numbers and lengths of subbasal nerves despite an unremarkable slit-lamp examination. Therefore, IVCM may be useful in the management of patients with corneal allodynia.

Imaging Microscopic Features of Keratoconic Corneal Morphology.

Purpose:To search for gold-standard histology indicators using alternative imaging modalities in keratoconic corneas.Methods:Prospective observational case–control study. Fourteen keratoconic corneas and 20 normal corneas (10 in vivo healthy subjects and 10 ex vivo donor corneas) were examined. Images of corneas were taken by spectral domain optical coherence tomography (SD-OCT) and in vivo confocal microscopy (IVCM) before keratoplasty. The same removed corneal buttons were imaged after keratoplasty with full-field optical coherence microscopy (FFOCM) and then fixed and sent for histology. Controls consisted of normal subjects imaged in vivo with IVCM and donor corneas imaged ex vivo with FFOCM. Corneal structural changes related to pathology were noted with each imaging modality. Cell density was quantified by manual cell counting.Results:Keratoconus indicators (ie, epithelial thinning/thickening, cell shape changes, ferritin deposits, basement membrane anomalies, Bowman layer thinning, ruptures, interruptions, scarring, stromal modifications, and appearance of Vogt striae) were generally visible with all modalities. Additional features could be seen with FFOCM in comparison with gold-standard histology, particularly in the Bowman layer region, whereas the combination of SD-OCT plus IVCM detected 76% of those features detected in histology. Three-dimensional FFOCM imaging aided interpretation of two-dimensional IVCM and SD-OCT data. Basal epithelial cell and keratocyte densities were significantly lower in patients with keratoconus than those in normals (P < 0.0001).Conclusions:Structural and cellular assessment of the keratoconic cornea by means of either in vivo SD-OCT combined with IVCM or ex vivo FFOCM in both cross-sectional and en face views can detect as many keratoconus indicators as gold-standard histology.

Comparison of human corneal cell density by age and corneal location: an in vivo confocal microscopy study.

BackgroundPeripheral and central regions of the cornea are optically different and have different repair capacity and pathology. For this reason, we characterized the cellular morphology and quantified the cell density of the central and peripheral regions of the cornea with age.MethodsEighty healthy subjects were enrolled in the study and divided into four groups according to age: A (0–19 years), B (20–39 years), C (40–59 years), and D (>60 years). In vivo confocal microscopy was used to measure the following parameters for the central and peripheral regions of the cornea: average cellular density and area of the superficial and basal epithelium; average density of the anterior and posterior keratocytes; average endothelial cell density and cellular area; percentage of hexagonal endothelial cells.ResultsStatistically significant differences between the central and peripheral cornea were observed for the cellular density of basal epithelial cells in group A. The density of keratocytes in the anterior stroma was significantly greater in the central region compared with the peripheral region in group B and group C. The percentage of hexagonal cells in the endothelial layer was significantly greater in the central region compared with the peripheral region. Age-related changes were found in peripheral basal epithelial cell density, central and peripheral endothelial cell density, and the percentage of hexagonal endothelial cells.ConclusionBoth similarities and differences in morphology of the central and peripheral regions of the transparent cornea were observed. These observations would provide a histological basis for further studies to define its regional pathological mechanisms.

Evaluation of the Corneal Layers in Meibomian-Gland-Dysfunction-Related Dry Eye by In Vivo Slit-Scanning Confocal Microscopy

ABSTRACTIn the current study it was aimed to evaluate the findings of cornea in Dry Eye related Meibomian Gland Dysfunction through in vivo confocal microscopy. 30 patients of Dry Eye related Meibomian Gland Dysfunction (DEMGD) and 30 healty individuals were included. 46 eyes of 30 DEMGD patients (group 1) and 46 eyes of 30 healthy individuals (group 2) were formed as control group and images were captured from the centre of the cornea. 26 of the patients (%86,6) in Group 1 were male, and four of them (%13,4) were female and 25 of healthy individuals (% 83,3) were male and 5 of them(%16,7) were female. The ages of the patients in Group 1 were between 23-67 (51,58±13,4 on average). The ages of the healthy individuals in Group 2 were between 23-67 (51,45±10,4 on average). Tear film break-up time and Schirmer 1 values were significantly lower in the MGDDE group than the control group (p<0.001). There were statistically significant intergroup differences in basal epithelial cell density and area and stromal nerve thickness (p<0.05). Surface epithelium changes, anterior stromal hyperreflectivity and subepithelial nerve morphology changes were not observed in the control group. As a result, some of the effects on cornea tissue caused by Dry Eye related Meibomian Gland Dysfunction were able to be visualized with confocal microscopy at micro level.

Near-term analysis of corneal epithelial thickness after cataract surgery and its correlation with epithelial cell changes and visual acuity

To quantify corneal central epithelial thickness and cell changes 2 weeks after cataract surgery and correlate it with corrected distance visual acuity (CDVA). Eye and ENT Hospital of Fudan University, Shanghai, China. Prospective observational study. Patients having cataract surgery were assessed preoperatively and 1, 2, 3, 5, 7, and 14 days postoperatively. Anterior segment spectral-domain optical coherence tomography and corneal confocal laser scanning microscopy were used to measure central epithelial thickness, central corneal thickness (CCT), corneal basal epithelial cell density, and Langerhans cell density. The CCT and central epithelial thickness were significantly increased on 1 day postoperatively. From 1 day to 14 days, the CCT gradually decreased but was greater than the baseline value, whereas the central epithelial thickness declined to near baseline values at 3 days, became thinner at 5 and 7 days, and then returned to baseline at 14 days. The corneal basal epithelial cell density increased significantly postoperatively. Significant Langerhans cell infiltration was seen at 3 days and 5 days. Significant correlations were found between CDVA and the central epithelial thickness and CCT. The maximum increase in central epithelial thickness and CCT correlated with the lowest achieved values of CDVA postoperatively. Patients with significant edema at 1 day had worse CDVA at 14 days. Near-term epithelial remodeling occurred, initially appearing as a thickening that might be attributed to edema. This was followed by thinning, possibly caused by inflammation, and finally reaching baseline levels. Edema of the corneal epithelium was related to visual recovery after cataract surgery.

Effects of Corneal Collagen Crosslinking on Confocal Microscopic Findings and Tear Indices in Patients with Progressive Keratoconus.

Background:To evaluate any change in tear indices and confocal microscopic findings after corneal collagen crosslinking (CXL) in patients with progressive keratoconus.Methods:Thirty-two consecutive eyes from 23 patients having progressive keratoconus were enrolled in this prospective, interventional cohort study. The standard crosslinking surgery was performed for all patients. Visual, refractive, and topographic evaluations were done before and at 6 months after surgery. Tear function tests and confocal microscopic examination were performed before and at 1 month and 6 months after the procedure.Results:There was no significant change in Schirmer-1 test results and tear osmolarity at 1 month and 6 months after CXL. Using confocal microscopy, all eyes showed reduced or absent subepithelial nerve plexus. Differences in basal epithelial cell density, epithelial mean cell area, and keratocyte density in anterior and middle stroma and endothelial cell pleomorphism were all significant at 1 month and 6 months after CXL (P < 0.05). No significant change was noted in endothelial cell count and their polymegathism at 6 months follow-up. Significant improvement was noted in uncorrected visual acuity, best corrected visual acuity, flattest corneal meridian (K2), and maximum keratometry in Pentacam (Kmax) after 6 months of the procedure.Conclusions:While CXL would have no effect on tear indices and endothelial cell count, it can cause a significant reduction in subepithelial nerve plexus and significant alterations in epithelial cell density in the anterior and middle stroma.

In Vivo Confocal Microscopic Imaging of the Cornea After Femtosecond and Excimer Laser-assisted Penetrating Keratoplasty.

To examine the microstructure of the cornea after excimer and femtosecond laser-assisted penetrating keratoplasty (ELAK and FLAK) in eyes with Fuchs' dystrophy and keratoconus. Fifty-seven patients were divided into four groups according to corneal disease and surgical technique: Fuchs' dystrophy and ELAK (n = 9; mean age: 70.4 ± 10.6 years); Fuchs' dystrophy and FLAK (n = 13; mean age: 64.3 ± 11.2 years); keratoconus and ELAK (n = 9; mean age: 47.4 ± 13.9 years); and keratoconus and FLAK (n = 9; mean age: 43.5 ± 13.8 years). The control group comprised individuals without ocular disease (n = 17; mean age: 39.9 ± 17.3 years). In vivo investigation of the corneal graft and graft-host junction zone was performed with confocal corneal microscopy. All corneal grafts were transparent and no rejection reaction could be observed during the follow-up period. Confocal microscopy revealed no difference in basal epithelial cell density compared to controls. Anterior keratocyte density was lower than in the control group (818 ± 131 cells/mm(2)) in all four treatment groups (596 ± 174, 586 ± 113, 529 ± 75, 552 ± 91 cells/mm(2)). Langerhans cells could barely be seen; there was no difference in the cutting edge configuration and wound integrity. In vivo confocal microscopy provided evidence that good alignment of graft-host junction could be created with both techniques. The excimer laser was not inferior to the femtosecond laser in performing corneal cuts. The low density of Langerhans cells revealed well-controlled cellular immunological response and sustained corneal integrity in both laser groups.

Limbal Basal Cell Density Decreases in Limbal Stem Cell Deficiency

To investigate changes in limbal basal epithelial cell density in eyes with limbal stem cell deficiency (LSCD) using in vivo confocal laser scanning microscopy. Retrospective observational comparative study. A total of 43 eyes of 30 patients diagnosed with LSCD were included in the study. Ten eyes from normal subjects were included as control. Confocal imaging of the central cornea, and the superior, nasal, inferior and temporal limbus were collected using the Heidelberg Retina Tomograph III Rostock Corneal Module. Basal cell density in all locations was measured by 2 independent observers. The mean basal cell density of the normal group was 9264 ± 598 cells/mm(2) in the cornea and 7120 ± 362 cells/mm(2) in the limbus. In the LSCD group, the mean basal cell density in the cornea decreased 31.0% (6389 ± 1820 cells/mm(2), P < .001) and in the limbus decreased 23.6% (5440 ± 1123 cells/mm(2), P < .001) compared to that in the control. There was a trend of basal cell density decline in more advanced stages of LSCD. The basal cell density declined in the unaffected regions at a similar degree as that in the affected region in sectoral LSCD (P > .05). The basal cell diameter increased by 24.6% in the cornea (14.7 μm) and by 15.7% in the limbus (15.5 μm) compared to the control. Basal cell density in both central cornea and limbus decreases in LSCD. Limbal stem cells (LSCs) are affected globally and basal cell density could be used as a parameter to measure LSC function at the early stages of the disease process.

Ocular Surface Alterations and In Vivo Confocal Microscopic Features of Corneas in Patients With Newly Diagnosed Graves' Disease.

To evaluate the ocular surface characteristics and corneal microstructure in patients with newly diagnosed Graves disease (GD) with no evidence of active thyroid eye disease (TED). Eighty eyes of 40 patients with newly diagnosed GD and 40 age-matched control subjects were recruited in this cross-sectional study. All participants underwent ocular surface tests in the order of tear break-up time (BUT), lissamine green (LG) staining, Schirmer I test with anesthesia, and ocular surface disease index (OSDI) questionnaire. Basal epithelial cell, keratocyte, and endothelial cell densities and subbasal nerves were evaluated using in vivo confocal microscopy (IVCM). Independent sample t test, χ test, and Mann-Whitney U test were used for statistical analysis. Patients with GD had higher OSDI (5.9 ± 6.6 vs. 1.7 ± 2.4, respectively, P ≤ 0.001) and LG staining scores (0.5 ± 0.6 vs. 0.2 ± 0.4, respectively, P = 0.003), and lower BUT scores (7.3 ± 2.5 vs. 9.9 ± 1.7, respectively, P < 0.001) compared with those of control subjects. Patients with GD had lower mean basal epithelial cell density (3928 ± 657 cells/mm² vs. 4771 ± 622 cells/mm², respectively) and total subbasal nerve density (958 ± 394 cells/mm² vs. 1416 ± 744 cells/mm², respectively) and higher subbasal nerve tortuosity (2.7 ± 0.8 vs. 1.6 ± 0.6, respectively) compared with those of control subjects (P < 0.001). There was a statistically significant negative correlation between the duration of symptoms of hyperthyroidism and BUT (rho = -0.273, P = 0.014) and a positive correlation between LG staining scores (rho = 0.329, P = 0.003). A significant reduction in BUT (rho = -0.238, P = 0.003) and epithelial cell density (rho = -0.174, P = 0.029) and an increase in OSDI scores (rho = 0.328, P = 0.003) were found with increasing exophthalmometry measurements. Ocular surface alterations begin early in the course of Graves disease before the onset of overt TED.

In vivo corneal confocal microscopic analysis in patients with keratoconus.

To quantify corneal ultrastructure using laser scanning in vivo confocal microscopy (IVCM) in patients with keratoconus and control subjects. Unscarred corneas of 78 keratoconic subjects without a history of contact lens use and 36 age-matched control subjects were evaluated with slit-lamp examination (SLE), corneal topography and laser scanning IVCM. One eye was randomly chosen for analysis. Anterior and posterior stromal keratocyte, endothelial cell and basal epithelial cell densities and sub-basal nerve structure were evaluated. IVCM qualitatively demonstrated enlarged basal epithelial cells, structural changes in sub-basal and stromal nerve fibers, abnormal stromal keratocytes and keratocyte nuclei, and pleomorphism and enlargement of endothelial cells. Compared with control subjects, significant reductions in basal epithelial cell density (5817±306 cells/mm(2) vs 4802±508 cells/mm(2), P<0.001), anterior stromal keratocyte density (800±111 cells/mm(2) vs 555±115 cells/mm(2), P<0.001), posterior stromal keratocyte density (333±34 cells/mm(2) vs 270±47 cells/mm(2), P<0.001), endothelial cell density (2875±223 cells/mm(2) vs 2686±265 cells/mm(2), P<0.001), sub-basal nerve fiber density (31.2±8.4 nerves/mm(2) vs 18.1±9.2 nerves/mm(2), P<0.001), sub-basal nerve fiber length (21.4±3.4 mm/mm(2) vs 16.1±5.1 mm/mm(2), P<0.001), and sub-basal nerve branch density (median 50.0 (first quartile 31.2 - third quartile 68.7) nerve branches/mm(2) vs median 25.0 (first quartile 6.2 - third quartile 45.3) nerve branches/mm(2), P<0.001) were observed in patients with keratoconus. Significant microstructural abnormalities were identified in all corneal layers in the eyes of subjects with keratoconus using IVCM. This non-invasive in vivo technique provides an important means to define and follow progress of microstructural changes in patients with keratoconus.

In Vivo Confocal Microscopic Changes of the Corneal Epithelium and Stroma in Patients With Herpes Zoster Ophthalmicus

To analyze the density and morphology of corneal epithelial cells and keratocytes by invivo confocal microscopy (IVCM) in patients with herpes zoster ophthalmicus (HZO) as associated with corneal innervation. Prospective, controlled and masked cross-sectional study. setting: Single-center study. Thirty eyes with the diagnosis HZO and their contralateral clinically unaffected eyes, 15 eyes of 15 normal controls. intervention procedures: Invivo confocal microscopy and corneal esthesiometry of the central cornea. Changes in morphology and density of the superficial and basal epithelial cells and stromal keratocytes, and correlation with corneal sensation. The density of superficial epithelial cells in HZO eyes with severe sensation loss (766.5 ± 25.2 cells/mm(2)) was significantly lower than both healthy control eyes (1450.23 ± 150.83 cells/mm(2)) and contralateral unaffected eyes (1974.13 ± 298.24 cells/mm(2)) (P= .003). Superficial epithelial cell size (1162.5μm(2)) was significantly larger in HZO eyes with severe loss of sensation, as compared to contralateral (441.46 ± 298.14) or healthy eyes (407.4± 47.2μm(2); all P < .05). The density of basal epithelial cells, anterior keratocytes, and posterior keratocytes did not show statistical significance between patients, controls, and contralateral unaffected eyes. Changes in superficial epithelial cell density and morphology correlated strongly with corneal sensation. Invivo confocal microscopy reveals profound HZO-induced changes in the superficial epithelium, as demonstrated by increase in cell size, decrease in cell density, and squamous metaplasia. We demonstrate that these changes strongly correlate with changes in corneal innervation in eyes affected by HZO.

Corneal microstructural changes in nerve fiber, endothelial and epithelial density after cataract surgery in patients with diabetes mellitus.

The aim of this study was to analyze microstructural corneal changes following phacoemulsification of cataract with intraocular lens insertion in diabetes mellitus (DM). Prospective study of consecutive patients undergoing phacoemulsification with intraocular lens insertion, over a period of 6 months. Age, gender, serum glycosylated hemoglobin A1c levels, and effective phacoemulsification time were recorded. Anterior segment optical coherence tomography and corneal in vivo confocal microscopy were performed preoperatively and 1-month postoperatively. Subbasal nerve plexus (SBN) density, basal epithelial cell density, and endothelial cell density (ECD) were quantitatively analyzed. Twenty-eight patients with type 2 DM (71.2 ± 7.6 years) and 23 healthy controls (mean age, 74.4 ± 7.4 years) were recruited. Mean hemoglobin A1c level was 7.5% in patients with DM and 5.7% in the control group (P < 0.0001). A significant reduction in SBN density was noted postoperatively in both DM (P < 0.0001) and non-DM groups (P < 0.0001). Patients with DM had a lower mean SBN density compared with non-DM group, before (P < 0.0001) and after surgery (P < 0.0001). Longer effective phacoemulsification time correlated with a greater decrease in ECD postoperatively in the whole cohort (P < 0.0001), and in the control (P = 0.002) and DM (P = 0.039) groups independently. There was no significant difference in preoperative ECD between the DM group (2254 +/- 426 cells/mm(2)) and non-DM group (2384 +/- 438 cells/mm(2); P = 0.2). [corrected]. Subbasal nerve density is reduced after cataract surgery in patients with and without DM. However, lower initial SBN density in patients with DM may predispose them to develop diabetic keratopathy. DM does not predispose to greater endothelial loss following phacoemulsification.

Evaluation of Corneal Microstructure in Pseudoexfoliation Syndrome and Glaucoma: In Vivo Scanning Laser Confocal Microscopic Study

Purpose: To quantitatively evaluate corneas of patients with pseudoexfoliation syndrome (PXS) and pseudoexfoliation glaucoma (PXG) using in vivo scanning laser confocal microscopy (IVCM).Materials and Methods: The study population comprised 30 patients with PXS, 30 patients with PXG, and 30 normal control subjects. IVCM of the cornea was performed on all participants using the Rostock Cornea Module of the Heidelberg Retinal Tomograph (HRT). Mean outcome measures included density of basal epithelial cells, endothelial cells, and anterior and posterior keratocytes; and tortuosity and density of subbasal plexus nerves.Results: Mean densities of basal epithelial cells, endothelial cells, anterior and posterior keratocytes, and subbasal nerves differed significantly among the three groups. Subbasal nerve densities were significantly diminished in PXS and PXG patients (12.36 ± 2.89 and 6.8 ± 3.42 mm/mm2, respectively) compared with that of control subjects (16.13 ± 3.42 mm/mm2) (p < 0.05). Mean densities of anterior and posterior stromal keratocytes were significantly lower in PXS and PXG patients compared with control subjects (p < 0.05). Endothelial cell densities were 3073.63 ± 654.49, 2592.60 ± 276.36, and 2110.20 ± 620.53 cells/mm2 for control, PXS, and PXG groups, respectively (p < 0.05). The percentages of endothelial cell polymegathism and pleomorphism were higher in PXS and PXG patients compared with control subjects. Endothelial cell polymegathism and pleomorphism were more frequently associated with PXG.Conclusions: Results of this study demonstrate the existence of alterations in the (i) density of cells in the various layers of the cornea, (ii) cellular configuration of corneal endothelial cells, and (iii) density/diameter of the subbasal nerve plexus in patients with PXS, and that such alterations are common in patients with PXG. It would be beneficial to employ IVCM to assess the severity of pseudoexfoliation keratopathy (PXK).

Effects of Long-Term Antiglaucoma Eye Drops on Conjunctival Structures: An In Vivo Confocal Microscopy Study.

Purpose. The study was aimed at comparing the long-term effects of different antiglaucoma eye drops on conjunctival structures using laser scanning confocal microscopy. Methods. Eighty patients diagnosed with primary open-angle glaucoma and twenty healthy volunteers were included in this study. The participants were divided into 5 groups according to the different medications. The lachrymal film break-up time, Schirmer's I test, and Ocular Surface Disease Index Questionnaire were performed in all subjects. The confocal microscopy was used to observe the basal epithelial cell density (ECD), goblet cell density (GCD), dendritic cell density (DCD), and subepithelial collagen fiber diameter (SFD). Results. Statistically significant differences were found among the control group and the antiglaucoma therapy groups in the values of three clinical data (P < 0.05). The GCD, DCD, and SFD showed significant differences in all glaucoma groups when compared to the control (P < 0.001). Moreover, the prostaglandin group differed from the other antiglaucoma therapy groups in the GCD and SFD (P < 0.05). Conclusions. Our study confirmed the significant differences in the conjunctival structures based on the effects of antiglaucoma medications. Less pronounced changes were found in the patients treated with prostaglandin analogue than in the other kinds of antiglaucoma therapies.

Characteristics of the cornea in patients with pseudoexfoliation syndrome.

To quantify the morphological alterations in corneal nerve fibers and cells in patients with pseudoexfoliation syndrome (PEX) and their relationship with the presence of hyperreflective endothelial deposits observed using in vivo confocal microscopy. One eye each of 37 patients with PEX and 20 age-matched healthy control subjects was evaluated by in vivo corneal confocal microscopy. Patients with PEX were further classified into two groups: those with and without hyperreflective endothelial deposits. We evaluated the densities of basal epithelial cells, anterior and posterior stromal keratocytes, and endothelial cells and structure of sub-basal nerve fibers. The mean anterior and posterior stromal keratocyte and endothelial cell densities and corneal sub-basal nerve plexus variables were significantly lower in patients with PEX compared with those in healthy control subjects. The mean basal epithelial cell density did not significantly differ. Eyes with PEX presented decreased corneal sub-basal nerve plexus variables and cell densities in all corneas, except for the mean basal epithelial cell density. Further, a trend of lower corneal sub-basal nerve plexus measurements in patients with hyperreflective endothelial deposits compared with those without endothelial deposits was observed.

The Impact of Type 1 Diabetes Mellitus on Corneal Epithelial Nerve Morphology and the Corneal Epithelium

Diabetic corneal neuropathy can result in chronic, sight-threatening corneal pathology. Although the exact etiology is unknown, it is believed that a reduction in corneal sensitivity and loss of neurotrophic support contributes to corneal disease. Information regarding the relationship between nerve loss and effects on the corneal epithelium is limited. We investigated changes in the corneal epithelium and nerve morphology using three-dimensional imaging invivo and in situ in a streptozotocin-induced diabetic mouse model. Streptozotocin-treated mice showed increased levels of serum glucose and growth retardation consistent with a severe diabetic state. A reduction in the length of the subbasal nerve plexus was evident after 6 weeks of disease. Loss of the subbasal nerve plexus was associated with corneal epithelial thinning and a reduction in basal epithelial cell density. In contrast, loss of the terminal epithelial nerves was associated with animal age. Importantly, this is the first rodent model of type 1 diabetes that shows characteristics of corneal epithelial thinning and a reduction in basal epithelial cell density, both previously have been documented in humans with diabetic corneal neuropathy. These findings indicate that in type 1 diabetes, nerve fiber damage is evident in the subbasal nerve plexus before terminal epithelial nerve loss and that neurotrophic support from both the subbasal nerve plexus and terminal epithelial nerves is essential for the maintenance of corneal epithelial homeostasis.

Confocal Microscopy Analysis of Corneal Changes After Photorefractive Keratectomy Plus Cross-Linking for Keratoconus: 4-Year Follow-up

To analyze corneal confocal microscopy changes after combined photorefractive keratectomy (PRK) plus the cross linking (CXL) procedure. Prospective interventional case series. At the Department of Basic Medical Sciences, Neuroscience, and Sense Organs of the University of Bari, Bari, Italy, 17 eyes of 17 patients with progressive keratoconus underwent confocal microscopy examination before and after 1, 3, 6, 12, 18, and 48 months following PRK plus the CXL procedure. The main outcome measures were mean superficial epithelial cell density; mean basal epithelial cell density; mean anterior, mid and posterior keratocyte density; qualitative analysis of stromal backscatter; sub-basal and stromal nerve density parameters; and mean endothelial cell density. During the 4-year follow-up, the mean superficial epithelial cell density, mean basal epithelial cell density and mean endothelial cell density remained unchanged (P > 0.05). The anterior mid-stromal keratocyte density showed a significant decrease (P < 0.05) as compared with preoperative values, and the posterior stromal keratocyte density showed a significant increase at 1 and 3 months of follow-up. Sub-basal and stromal nerve density parameters were significantly decreased until postoperative month 6 (P < 0.05 at 1, 3, and 6 months) and then tended to increase up to preoperative values by the 18th postoperative month. Corneal changes after the PRK plus CXL procedures seem to be pronounced and long lasting as far as keratocyte density of the anterior and mid stroma is concerned. Sub-basal nerve densities tend to reach preoperative values 6 months after surgery.