Corneal Density Research Articles

Normal Values of Corneal Optical Densitometry Using Pentacam Scheimpflug Camera

1.1.Purpose: The purpose of the study was to illustrate the range of normal values of corneal densitometry using Pentacam Scheimpflug camera. 1.2.Methodology: Prospective study was conducted at tertiary care Amanat eye hospital. 490 eyes of 490 participants of different age groups were added. All scans were performed in diagnostics room with uniform ambient light, performed by trained ophthalmic technologist. All participants were Pakistani of different ethnic groups. Only one eye of each participant was included to control biasness. T test, One-way ANOVA, pearson correlation coefficient and linear regression model tests were applied for analysis. 1.3.Results: 490 eyes; 247 right eyes and 243 left eyes were analyzed. Mean age was 41.7±15.27 years (range 20-81 years) with 48.4% male and 51.6% females. based on corneal depth; highest backward scattering of light was observed in anterior (120 µm) layer (20.6±8.52 GSU) than central and posterior layers 13.6±5.17 GSU and 11.7±3.99 GSU respectively. The difference was statistically significant among layers with p< 0.001. Based on corneal surface, minimum backscattering was noted in central 0-6mm zone which increases from central to limbal zone; 0-2mm zone was 13.2±3.81 GSU, 2-6mm zone was 12.6±3.68 GSU, 6-10mm zone was 16.0±8.90 GSU and 10-12mm zone was 22.1±8.26 GSU. The difference was statistically significant with p<0.001. Significant correlation of corneal densitometry and age was observed r= 0.677, p<0.001. 1.4.Conclusion: Objective assessment of corneal densitometry can be made with Pentacam Scheimpflug. Normative values of corneal density may be used in routine clinical practice and provided a reference for future research.

Innervation of the chick embryo cornea during development

Background To understand the distribution and development of corneal nerve in animal or human has an important significance for clinical and basic research of corneal diseases.At present, some studies on cornea nerve development and location have been performed.However, the quantified study on innervation and distribution of corneal nerve fibers as embryonic development has not been reported. Objective This study attempted to understand the distribution of corneal nerve fibers in the development of chick embryo, and to evaluate the changes of the length and density of corneal nerve fibers with aging of chick embryo. Methods Whole chick corneas with limbus were obtained from chick embryo aged 6-20 days (E6-E20), and corneal nerve fiber was labeled using immunofluorescence technique by anti-neuron-specific β-Ⅲ tubulin antibody.The corneas were radially cut into 4 parts, and the integrate corneal flat mounts were prepared with the upward epithelium and mounting with anti-fade fluorescent quenching buffer glycerin containing DAPI.Fluorescence microscope was used to capture the nerve fiber images in cornea, and cornea area and the number of nerve fiber bundles were exhibited by using Photoshop CS4.Cornea nerve fiber density and total length were measured by Imaris x64 7.4.2 software. Results Total cornea flat mounts showed that the nerve bundles grew from temporal scleral forward cornea limbus at E6-E8, and the nerve fibers formed the ring surrounding by limbus during E9-E10.Then the fibers extended forward the central cornea in E11 to E15 and developed into nerve fiber plexus on the whole cornea in E16 to E20.During the period of E6-E20, the corneal surface area, the length and density of corneal nerve fibers were gradually increased with the aging of chick embryo, showing statistically significant differences among different time points (F=127.007, 227.051, 67.748, all at P<0.01). The increase of the corneal area of the chick embryo presented a strong positive correlation with the extending of length of the corneal nerve fiber (r=0.863, P<0.01). Chick corneal nerve fiber bundle appeared at E13, with a number of (59.00±1.14)/mm2 and then increased to a peak of (576.75±29.16)/mm2 at E18 and reduced to (299.67±25.46)/mm2 at E20, with a significant difference among them (F=13.759, P=0.000). Conclusions Corneal nerve starts to develop in E9 of chick embryo, and the corneal surface area, the total length of the corneal nerve fibers and the density rapidly increase concurrently with the development of chick embryo. Key words: Cornea/innervation; Nerve fibers, corneal/embryology; Development; Ophthalmic nerve/physiology; Chick embryo

Long-Term Density Changes in Corneal Layers After Primary Pterygium Excision With Topical Mitomycin-C.

To evaluate the long-term change in average corneal densities at 18 months after primary pterygium excision with topical adjuvant mitomycin-C application, particularly the relationship between anterior and posterior corneal layer densities. Prospective observational case series. Patients were imaged with the Pentacam at 18 months after their surgery. Average corneal densities were the primary outcome and were compared with postoperative weeks 1, 4, and 12 data using paired t test. In all, 31 eyes of 31 patients were recruited. Mean age at time of operation was 62.0 ± 9.4 years. Mean best-corrected logarithm of the minimal angle of resolution visual acuity at 18 months was 0.14. The mean total anterior, central, and posterior average corneal densities were 30.6, 25.9, and 20.5 respectively. Compared with postoperative week 1 data, the anterior layer was reduced by 12.7% (P = 0.0144); however, there was no significant change in the central and posterior layers (P = 0.5353 and 0.0858, respectively). Subgroup analyses did not support the use of a 10- to 12-mm annulus as opposed to total-diameter data, and density reduction effect at 18 months from week 12 and week 1 seemed to be stronger in males (P = 0.0074 and 0.0042, respectively). Anterior corneal scars continued to diminish in density with time. Previous finding of a significant increase in posterior layer density at postoperative week 12 is likely not a result of optical phenomenon caused by a less dense anterior layer. Sex difference in terms of scar remodeling may be present.

Effects of genipin corneal crosslinking in rabbit corneas

To evaluate the effect of genipin, a natural crosslinking agent, in rabbit eyes. Department of Ophthalmology, Universidad Nacional de Colombia Centro de Tecnologia Oftalmica, Bogotá, Colombia. Experimental study. Exvivo rabbit eyes (16; 8 rabbits) were treated with genipin 1.00%, 0.50%, and 0.25% for 5 minutes with a vacuum device to increase corneal permeability. Penetration was evaluated using Scheimpflug pachymetry (Pentacam). In the invivo model (20 rabbits; 1 eye treated, 1 eye with vehicle), corneas were crosslinked with genipin as described. Corneal curvature, corneal pachymetry, and intraocular pressure (IOP) assessments as well as slitlamp examinations were performed 0,7, 30, and 60 days after treatment. In the exvivo model, Scheimpflug pachymetry showed deep penetration in the rabbit corneas with an increase in corneal density and a dose-dependent relationship. Corneal flattening was observed in treated eyes (mean 4.4 diopters ± 0.5 [SD]) compared with the control eyes. Pachymetry and IOP were stable in all evaluations. No eye showed toxicity in the anterior chamber or in the lens. Corneal crosslinking induced by genipin produced significant flattening of the cornea with no toxicity in rabbit eyes. This crosslinking could be useful in the treatment of corneal ectasia and in the modification of corneal curvature. None of the authors has a financial or proprietary interest in any material or method mentioned.

Investigation on the effects of eye drops of 0.3% hyaluronate sodium on ocular surface of after pterygium surgery

Objective To evaluate the the effects of 0.3% hyaluronate sodium eye drops on ocular surface of pterygium patients after limbal conjunctival autograft transplantation. Methods Prospective, double-blind, randomized, controlled clinical trial. Sixty eyes of 60 patients diagnosed as primary pterygium were randomly divided into two groups with 30 eyes in each group. All received pterygium resection combined with limbal conjunctival autograft transplantation by the same doctor. After operation, patients in the control group were given 0.5% levofloxacin, 0.1% fluorometholone eye drops 4 times a day. For that in treatment group, 0.3% sodium hyaluronate eye drops were added 1 day postoperatively, four times a day for 1 month. The follow-up time was 1 month. The healing of epithelium, the scores of clinical symptoms, corneal sensation, non-invasive breakup time of tear film (BUT), non-invasive tear meniscus height (TMH), and confocal microscopy examination were done and recorded. Results The scores of clinical symptoms at the 2, 3, 7 days after the surgery were lower in the treatment group than that in the control group(P 0.05). At day 2, the eyes with intact epithelium in treatment group was 17(57%), compared with control group only 9(30%)(χ2=4.344, P=0.037). TMH & BUT: at 14 and 28 days postoperatively, the TMH in the treatment group were higher than that in the control group(P 0.05). Corneal sensation: at each time point, there was no statistically significant difference between two groups(P>0.05). Confocal microscopy: at 7 days postoperatively, the epithelia of the pterygium resection area were assembled tightly without edema or inflammation cells infiltration in the treatment group; however, in the control group, some of the epithelial cells were swollen with inflammation cells infiltration. The corneal epithelial cells density was higher in the treatment group compared with the control group(P<0.05). Conclusion 0.3% hyaluronate sodium eye drops promote the healing of corneal epithelium, and significantly reduce the perioperative pain. Continual using 0.3% hyaluronate sodium eye drops could increase the TMH. Key words: Pterygium; Excision; Eye drops, hyaluronate sodium; Wound healing

Optical densitometric measurements of the cornea and lens in children with allergic rhinoconjunctivitis

BackgroundOur aim was to investigate the impact of allergic rhinoconjunctivitis on corneal and lenticular optical densitometry, pachymetry and anterior chamber depth in children.MethodsFifty‐four patients who had allergic rhinoconjunctivitis (study group) and 54 age‐matched healthy children (control group) were recruited in this cross‐sectional and comparative study. Corneal and lenticular optical densitometry, pachymetry, corneal volume and anterior chamber depth measurements were taken with the Scheimpflug imaging system.ResultsThe lens density and anterior chamber depth were similar between the groups (p > 0.05), while corneal density and thickness were significantly higher in the study group (p < 0.05). Although the corneal volume was higher in children with allergic rhinoconjunctivitis, the difference was not statistically significant (p = 0.07).ConclusionsThe cornea is affected in allergic rhinoconjunctivitis in respect to optical density and thickness, while the anterior chamber and lens are not influenced.

Acuité visuelle, pachymétrie et densité cornéenne après traitement par solution hyperosmolaire au chlorure de sodium 5 % dans l’œdème cornéen postopératoire

To evaluate the effectiveness of a hyperosmolar medication in corneal edema. This was a prospective randomized study, performed in patients with post-operative corneal edema. Two groups were created: group 1 treated with hypertonic eye drops of 5% sodium chloride with 0.15% sodium hyaluronate in addition to the usual post-operative treatment for 1 month; group 2 without treatment for edema. Visual acuity, pachymetry and corneal density were measured at 1 day, 1 week, 1 month, 3 months and 6 months following surgery. Forty-four patients were included in group 1 and 42 in group 2. Visual acuity was significantly better in group 1 than in group 2 at 7 days (0.84 logMAR vs 1.55 logMAR, P=0.019 CI 95% [-1.298;-0.128]) and was no longer different at one month, three and six months. Pachymetry decreased significantly in 7 days in group 1 (decrease of 17%, P=0.04, CI 95% [1.987; 258.305]), compared to group 2 (P=0.8, CI 95% [-132.9; 161.8]), but the difference between the 2 groups was not statistically significant (P=0.11, CI 95% [-16; 19.1]). Corneal density was also not significantly different between the two groups. Five percent sodium chloride hypertonic eye drops show a statistically significant reduction in post-operative corneal edema as shown by the improvement in visual acuity at one week and the downward trend in pachymetry.

The use of ocular anatomical measurements using a rotating Scheimpflug camera to assist in the Esclera® scleral contact lens fitting process.

To test for associations between Pentacam(®) derived topography variables and to evaluate the predictive power of those variables in relation to scleral contact lens (SCL) fit. Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, São Paulo-SP, Brazil. Prospective observational non-randomised, non-comparative study. Forty-seven patients (63 eyes) were indicated for the use of Esclera(®) SCL. All patients underwent Scheimpflug imaging before the initial SCL evaluation. The following parameters were measured by Pentacam: corneal elevations, thickness, density, and anterior chamber depth (ACD). Correlations between the SCL parameters and the Pentacam measurements were analysed with Pearson's correlation coefficients. A simple linear regression model was created for each lens parameter using the most-correlated Pentacam variable. In the total group, the results show correlations between the SCL parameters and the corneal astigmatism, ACD and pentacam-measured corneal height (Hm), with p<0.001 each. In addition, an inverse correlation between the lens sagittal depth (LSD) and the anterior radii minimum was shown (p<0.001). In the keratoconus group, the results show correlations between the SCL parameters and ACD and Hm (p<0.001, each). An inverse correlation between the LSD and the total thickness corneal density average was also observed (p=0.003). There was a positive correlation between the LSD and ACD, even as LD and ACD in the keratoconus group. Thus, these results suggest that certain Pentacam measurements can be good predictors of the most appropriate Esclera lens to be fitted in keratoconus patients.

Transient Corneal Edema After Phacoemulsification.

To determine the association between pre-operative and intra-operative factors leading to transient corneal edema after phacoemulsification. Cohort study. Department of Ophthalmology, Shifa Foundation Community Health Centre, Islamabad, from October 2011 to September 2012. Patients undergoing phacoemulsification and Intraocular Lens (IOL) implantation were enrolled in the study using consecutive non-probability sampling. Pre-operative risk factors including peripheral corneal degenerations, the type and density of cataract were documented. Surgical risk factors included the incision site, the type of intraocular lens, the phacotechnique and the phacopower time. Postoperatively the patients were assessed for corneal clarity and the degree of striate keratopathy. Statistical analysis was done using SPSS version 17. There were 43% male and 57% female patients (n = 182). Mean age was 58.92 ± 13.00 years (median and mode-60 years). Factors which increased the risk of transient corneal edema after phacoemulsification included hypertension (p = 0.022), dense nuclear cataracts (p=0.006), divide and conquer technique (p = 0.008), duration of phacopower use (p < 0.001) and peripheral corneal degenerations (p < 0.001). Patients with peripheral corneal degenerations and dense nuclear cataracts had significantly higher rates of postoperative corneal edema. Use of phaco-chop technique and less phaco-power time helps in decreasing corneal edema.

The clinical effect of miniature glaucoma drainage device implantation combined with phacoemulsification for angle-closure glaucoma with cataract

Objective To observe the treatment effect of Ex-PRESS miniature glaucoma drainage device implantation combined with phacoemulsification and intraocular lens implantation for the primary angle-closure glaucoma (PACG) with cataract. Methods Fifty-five eyes of 54 cases of PACG with cataract were selected, and they were randomly devided into clinical trail group(30 eyes of 30 cases) and control group (25 eyes of 24 cases). The clinical trail group was treated with Ex-PRESS miniature glaucoma drainage device implantation combined with phacoemulsification and intraocular lens implantation. The control group was treated with trabeculectomy combined with phacoemulsification and intraocular lens implantation. The visual acuity, intraocular pressure (IOP), corneal endothelium and central anterior chamber depth (ACD) were recorded and compared. Results At the last review of trail group after operation, the visual acuity (log MAR) was (0.47±0.31), which was better than the preoperative visual acuity (0.75±0.63)(P=0.002). The postoperative IOP in the clinical trail group decreased compared with the preoperative one (P<0.05). The ACD of the clinical trail group and the control group obviously increased after operation, and the difference in ACD between the two groups after operation was not statistically significant (P=0.451). The difference in corneal endothelial density between preoperation and postoperation in the clinical trail group was not statistically significant (P=0.162). The success rates of the clinical trail group and the control group were 96.67% and 92.00% respectively 6 months after surgery, and the difference was not statistically significant (P=0.585). The complication rate after operation of the clinical trail group (3.33%) was lower than that of the control group (24.00%)(P=0.022). Conclusion The operation of Ex-PRESS miniature glaucoma drainage device implantation combined with phacoemulsification and intraocular lens implantation, which can reduce IOP and improve visual acuity evidently with less complications, is a safe and effective combined operation for glaucoma with cataract. Key words: Glaucoma, angle-closure, primary; Cataract; Trabeculectomy; Phacoemulsification, aspiration; Drainage implant, glaucoma, miniature(Ex-PRESS)

Effect of Viscous Agents on Corneal Density in Dry Eye Disease.

To investigate the effect of the viscous agents, hydroxypropyl methylcellulose (HPMC), carbomer, povidone, and a combination of HPMC and povidone on corneal density in patients with dry eye disease. In total, 98 eyes of 49 patients suffering from dry eye and 65 eyes of 33 healthy age-matched individuals were included in this prospective, randomized study. Corneal morphology was documented with Scheimpflug photography and corneal density was analyzed in 5 anatomical layers (epithelium, bowman membrane, stroma, descemet's membrane, and endothelium). Corneal density was evaluated for the active ingredients HPMC, carbomer, povidone, and a combination of HPMC and povidone as the viscous agents contained in the artificial tear formulations used by the dry eye patients. Data were compared to the age-matched healthy control group without medication. Corneal density in dry eye patients was reduced in all 5 anatomical layers compared to controls. Corneal density was highest and very close to control in patients treated with HPMC containing ocular lubricants. Patients treated with lubricants, including carbomer as the viscous agent displayed a significant reduction of corneal density in layers 1 and 2 compared to control. HPMC containing ocular lubricants can help to maintain physiological corneal density and may be beneficial in the treatment of dry eye disease.

Measurement of In Vivo Three-Dimensional Corneal Cell Density and Size Using Two-Photon Imaging in C57BL/6 Mice

ABSTRACTPurpose: To measure the cell size and cell density in five layers of the central cornea in the widely used inbred C57BL/6 mouse strain using in vivo three-dimensional (3D) two-photon (2PH) imaging.Methods: Corneas were scanned using a 2PH laser scanning fluorescence microscope after staining with plasma membrane stain and Hoechst 33342. Good quality 3D images were selected for the cell density and cell size analysis. Cell density was determined by counting the cell nuclei in a predefined cube of 3D images. Cell size measurements, including cell surface area, cell volume, nuclear surface area and nuclear volume, were automatically quantified using the Imaris software. The cell and nuclear surface-area-to-volume ratio (S:V ratio) and the cell nuclear-cytoplasmic ratio (N:C ratio) were calculated.Results: The highest cell density was observed in the basal epithelium and the lowest in the posterior stroma. The highest cell surface area was found in the anterior stroma, and the highest cell volume was observed in the superficial epithelium. The lowest cell surface area and cell volume were both found in the basal epithelium. The highest S:V ratio was observed in the basal epithelium and the lowest in the superficial epithelium. The highest cell nuclear surface area and volume were both observed in the superficial epithelium and the lowest in the basal epithelium. The highest cell nuclear S:V ratio was observed in the basal epithelium and the lowest in the superficial epithelium. The highest N:C ratio was found in the basal epithelial cells and the lowest in the posterior keratocytes.Conclusions: We are the first to quantify the cell density and size parameters, including cell surface area and volume, cell nuclear surface area and volume, and the S:V ratio, in the five layers of the central cornea. These data provide important cell morphology features for the study of corneal physiology, pathology and disease in mice, particularly in C57BL/6 mice.

Monitoring corneal densities following primary pterygium excision with adjuvant topical mitomycin-C application--an observational study of corneal scar changes.

Corneal densitometry is an inherent feature of the Pentacam device. We aim to assess the changes in corneal scar density with serial Scheimpflug images following primary pterygium excision with topical application of mitomycin-C. We recruited patients who underwent primary, single-headed pterygium excision with topical adjuvant mitomycin-C. Scheimpflug images were taken at postoperative weeks 1, 4, and 12, and all patients received topical corticosteroid and antibiotic treatment for at least 4 weeks postoperatively. Corneal scar densities were generated by the software for analysis. Secondary outcome measures included intraocular pressures and pterygium recurrence at the end of 12 weeks. Changes in corneal densities between weeks 12, 4, and 1 were calculated. We recruited 31 eyes of 31 patients, of whom 16 were male patients and 15 were female patients, with 19 left and 12 right eyes. Mean age at operation was 62.0 ± 9.4 years. Mean reduction in density of the anterior 120 μm of cornea was -3.07 [95% confidence interval (CI), -6.600 to 0.460] and -3.455 (95% CI, -6.787 to -0.122) at postoperative 4 and 12 weeks, respectively, and mean reduction percentage was -4.7% (95% CI, -10.7% to 1.3%) and -6.3% (95% CI, -11.8% to -0.7%), respectively. No steroid response or pterygium recurrence was reported. Corneal densitometry is an objective measure to detect scar changes in zones and layers. The overall reduction of density was evident at 12 weeks postoperatively. These results might serve as baseline figures for future studies in assessing modulation of corneal scars over time.

Corneal epithelial changes of soft contact lens wearers under a transmission electron microscope

To investigate the difference in corneal epithelium between patients with and without soft contact lens (SCL) wearing, and to analyze corneal epithelial changes of the eyes with long-time SCL wearing. In this cross sectional study, the subjects were divided into two groups: 13 patients of daily SCL wearers and 11 control subjects who had never worn contact lenses. The flap of corneal epithelium was observed by transmission electron microscopy. The corneal epithelial microvillus density was compared between the two groups. Transmission electron micrographs of the control group showed a tight connection between cells, regularly aligned basal cells, and continuous basement membrane. Compared with the control group, SCL wearers showed incomplete basement membrane, swollen epithelial cells, swollen mitochondria, and widened intercellular interstices. The density of corneal epithelium microvilli [(0.071466 +/- 0.015889)/microm2 vs. (0.139851 +/- 0.024171)/micro2] was lower (t = 8.312, P < 0.05). Long-term SCL wearing can induce remarkable changes of corneal epithelial tissue, and the density of corneal epithelial microvilli decreases.

Research of anterior chamber triamcinolone acetonide injection during surgery for complicated cataract due to anterior uveitis

Objective To investigate the effect and the safety of triamcinolone acetonide(TA) injected in anterior chamber for patients who underwent the surgery for complicated cataract due to uveitis. Methods Forty eyes of 40 cases were divided into two groups randomly: the clinical trial group and control group.All patients underwent a clear corneal incision phacoemulsification combined with IOL implantation.TA 2mg was injected into anterior chamber during surgery in clinical trial group.Visual acuity, intraocular pressure(IOP), corneal endothelial density and anterior chamber exudation were examined and compared between two groups after surgery. Results Fibrin formation in trial group was significantly reduced than in control group and the difference was statistically significant. The differences in visual acuity, IOP and corneal endothelial density were not statistically significant between two groups. Conclusion Anterior chamber injection of TA is an effective and safe way to decrease anterior chamber exudation after the surgery for complicated cataract due to anterior uveitis. No adverse event was observed. Key words: Triamcinolone acetonide; Injection, anterior chamber; Cataract, complicated; Uveitis, anterior

The relationship of corneal nerve density and refractive error: a pilot study

The relationship of corneal nerve density and refractive error: a pilot study

Corneal topography analysis of stromalcornealdystrophies.

Objective:The aim was to compare the corneal topography and tomography parameters of macular corneal dystrophy (MCD), granular corneal dystrophy (GCD) and lattice corneal dystrophy (LCD) patients obtained by Scheimpflug imaging system.Methods:The charts, photographs and topography images of patients were reviewed retrospectively. This study included 73 eyes of 73 patients (28 MCD, 20 GCG and 25 LCD patients). Topography images were obtained by Pentacam (Oculus Optikgerate, Wetzlar, Germany). The densitometry readings at the corneal apex were used for the statistics.Results:The female to male ratio was 13/15 in MCD group, 12/8 in GCD group and 13/12 in LCD group. The mean age median age was 32, 45 and 53 years in MCD, GCD and LCD groups respectively. The groups were similar regarding the gender (p=0.861). The MCD group was significantly younger than the other two groups (p<0.001). The median (minmum-maximum) corneal densities were 100 (100-100), 68 (17-100) and 97 (34-100) Pentacam densitometry units in MCD, GCD and LCD groups respectively. The corneal density at the corneal apex was significantly higher in MCD group than in the other groups (p<0.001). The GCD and LCD groups were statistically similar in terms of density of the corneal apex (p=0.079). In MCD group, corneal thickness at the apex and at the thinnest location was significantly thinner, than in the other groups (p=.002 for thickness at apex between MCD and LCD, and p<.001 for all the remaining comparisons). In MCD group corneal volume was significantly smaller than in the other groups (p<.001 for all comparisons).Conclusion:Densitometry on Scheimpflug imaging system gives information on the density of corneal opacities.

Schleimpflug photography detects alterations in corneal density and thickness in patients with dry eye disease

Dry eye disease is a common ocular surface disease that significantly affects the quality of life. Little is known about a potential impact of the disease on corneal morphology. This study was carried out to investigate for the first time if dry eye disease induces changes in corneal density and thickness. In total 97 patients suffering from dry eye disease and 33 healthy age-matched individuals were included in this prospective, randomized study. Corneal morphology was documented with Scheimpflug photography and analyzed for central corneal thickness and corneal density in five anatomical layers (i.e. epithelium, Bowman membrane, corneal stroma, Descemet membrane and endothelium). Corneal density was significantly reduced in the epithelium (p = 0.0053), Bowman membrane (p = 0.0049) and Descemet's membrane (p = 0.0385) in patients with dry eye syndrome compared to healthy controls. This decrease was age-dependant. Furthermore, central corneal thickness was significantly reduced in patients with dry eye syndrome compared to the control group (p = 0.0495). The change was again dependent on age with lower values at higher age. Central corneal thickness increased with age in the control group. The results of this study indicate that corneal morphology is subject to significant alterations in patients with dry eye disease. Scheimpflug photography provides not only unique information in lens trials but is also able to detect changes of corneal anatomy. However, further investigations with other anterior segment imaging techniques, such spectral domain optical coherence tomography (SD OCT/Pentacam®) are necessary to further evaluate the clinical consequences of these findings.

Morphological changes of corneal subbasal nerve plexus in patients with ocular blunt trauma by in vivo confocal microscope

To evaluate morphological changes of corneal subbasal nerve plexus in patients with ocular blunt trauma using in vivo confocal microscope. A prospective study. Twenty-three consecutive zone 2 or zone 3 monocular contusion outpatients from the same ophthalmologist in the Affiliated Eye Hospital of Wenzhou Medical College were included in this study from December 2009 to December 2010. The 23 injured eyes divided into trauma group, and the contralateral 23 normal eyes were divided into control group. In vivo confocal microscope (IVCM) was performed in both groups at the first week after injury, and in trauma group at the first and the third month after injury. The main parameters for analyzing were corneal subbasal nerve plexus density, nerve trunks, nerve branching, total nerve number, and nerve tortuosity. Data were analyzed using a paired t-test and Wilcoxon signed-rank test to compare the difference of parameters between the control group and each time point of trauma group. A repeated measures analysis of variance (ANOVA) was used to analyze data on the three time points in the trauma group. All parameters of trauma group were changed significantly over time (F values: 16.272, 24.138, 63.393, 68.122, 91.463, all P values < 0.01) . Corneal subbasal nerve plexus density, nerve trunks, nerve branching, total nerve number were significantly decreased at the first week [(624.0 ± 109.9) µm/frame, 1.66 line/frame, 6.70 line/frame, 8.45 line/frame)] compared with control group [(1677.9 ± 87.1) µm/frame, 4.80 line/frame, 8.98 line/frame, 13.80 line/frame) (t = 8.998, 9.301, 9.119, 12.969; all P < 0.01)], and showed a continued downward trend with time. However, nerve trunk showed no significant changes at the first week (1.66 line/frame) and the first month (2.31 line/frame) (t = -1.518; P = 0.143). Nerve tortuosity was significantly increased at the first week (1.66) compared with control group (1.00) (t = -6.879; P < 0.01) , and then kept increasing gradually. At the first month after injury, the nerve tortuosity (3.20) was more obvious than the first week (P < 0.01) , and nerve regeneration could be observed. At the third month, the values of each parameters were gradually approaching levels of control group. Nerve trunks (4.00 line/frame), nerve branching (8.69 line/frame), total nerve number (13.26 line/frame) and nerve tortuosity (1.00) of trauma group showed no significant difference compared with control group (t = 3.117, 1.703, 3.325, -1.837; P = 0.079,0.792,0.392,0.392) , but nerve density [(1064.3 ± 93.3)µm/frame] was still less than control group (t = 5.736; P < 0.01). Injury of different zone showed no significant influence on all the parameters in trauma group (F values:0.119,0.032,0.296,0.053,0.143;P values: 0.733,0.859,0.592,0.821,0.709). IVCM can clearly display the histological features of corneal subbasal nerve plexus in patients with ocular blunt trauma. Corneal subbasal nerve plexus were morphologically abnormal within 3 months after injury, and gradually underwent from atrophy to regeneration over time.

Nonsensory Effects of Reduced Corneal Nerve Density in Congenital Glaucoma

Nonsensory Effects of Reduced Corneal Nerve Density in Congenital Glaucoma