Lens Changes Research Articles

Degradation of an Old Human Protein

Long-lived proteins exist in a number of tissues in the human body; however, little is known about the reactions involved in their degradation over time. Lens proteins, which do not turn over, provide a useful system to examine such processes. Using a combination of Western blotting and proteomic methodology, age-related changes to a major protein, γS-crystallin, were studied. By teenage years, insoluble intact γS-crystallin was detected, indicative of protein denaturation. This was not the only change, however, because blots revealed evidence of significant cross-linking as well as cleavage of γS-crystallin in all adult lenses. Cleavage at a serine residue near the C terminus was a major reaction that caused the release of a 12-residue peptide, SPAVQSFRRIVE, which bound tightly to lens cell membranes. Several other crystallin-derived peptides with double basic residues also lodged in the cell membrane fraction. Model studies showed that once cleaved from γS-crystallin, SPAVQSFRRIVE adopts a markedly different shape from that in the intact protein. Further, the acquired helical conformation may explain why the peptide seems to affect water permeability. This observation may help explain the changes to cell membranes known to be associated with aging in human lenses. Age-related cleavage of long-lived proteins may therefore yield peptides with untoward biological activity.

1268P - Visual Disturbances in Patients (PTS) with Anaplastic Lymphoma Kinase (ALK)-Positive Advanced Non-Small Cell Lung Cancer (NSCLC) Treated with Crizotinib

ABSTRACT Background Crizotinib is a potent, small-molecule ALK inhibitor with a high response rate in advanced ALK-positive NSCLC. In early phase studies, patients (pts) commonly reported mild visual disturbances. Here we characterize such visual effects with objective and subjective measures in an ongoing phase II study (PROFILE 1005). Methods Previously treated pts with advanced ALK-positive NSCLC received crizotinib 250 mg BID. Ophthalmological examinations, comprising best corrected visual acuity (BCVA), biomicroscopy, and fundoscopy, were performed at screening and after a visual effect event was reported, except for a subset of pts in France, where examinations were done every 4 cycles. In addition, on day 1 of each cycle, pts completed the Visual Symptom Assessment Questionnaire (VSAQ) that assessed the presence, frequency, timing, duration, and severity of visual effects and their impact on activities of daily living (ADL). Results As of Jan 2012, 901 pts had enrolled in PROFILE 1005; 21 - 27% were evaluable for ophthalmological examinations (visual acuity: 193/901; biomicroscopy: 239/901; fundoscopy: 239/901). There were no changes in BCVA, conjunctiva, cornea, anterior chamber, iris, lens, or fundus attributable to crizotinib. The most frequently reported ophthalmological finding was worsening of cataracts (right eye: 9%; left eye: 10%), which was not attributed to crizotinib. Visual effects as identified by the VSAQ were reported by 65% of pts (405/622) at cycle 2 (C2), 58% at C3 (323/558), 55% at C4 (287/519), and 50% at C5 (247/495). The most common were appearance of flashing lights, streamers/strings/floaters, and overlapping shadows. Most pts reported each event as lasting ≤1 min (C2: 63%; C3: 68%; C4: 72%; C5: 75%), occurring mostly in the morning (46–59%) and/or evening (70–74%). The majority of pts reported that visual effects were not at all or a little bothersome, with no or minimal impact on ADL. Similar results were observed in the French pt subset. Conclusions There were no objective ophthalmological changes associated with the visual effects on crizotinib. Pt-reported visual effects were frequent, but transient, with no or minimal impact on ADL. Disclosure B. Besse: Research funding: Pfizer. B. Solomon: Compensated advisory relationship: Pfizer. Research funding: Pfizer. A. Shaw: Compensated advisory relationship: Pfizer, Ariad, Chugai, Novartis, and Daiichi-Sankyo. Research funding: AstraZeneca and Novartis. D. Kim: Compensated advisory relationship: Pfizer. Honoraria: Pfizer. R. Schachar: Compensated employment: Pfizer. Stock ownership: Pfizer. K. Wilner: Compensated employment: Pfizer. Stock ownership: Pfizer. A. Reisman: Compensated employment: Pfizer. Stock ownership: Pfizer. C.H. Bartlett: Compensated employment: Pfizer. Stock ownership: Pfizer. S. Iyer: Compensated employment: Pfizer. All other authors have declared no conflicts of interest.

Radiation cataract

Until very recently, ocular exposure guidelines were based on the assumption that radiation cataract is a deterministic event requiring threshold doses generally greater than 2Gy. This view was, in part, based on older studies which generally had short follow-up periods, failed to take into account increasing latency as dose decreased, had relatively few subjects with doses below a few Gy, and were not designed to detect early lens changes. Newer findings, including those in populations exposed to much lower radiation doses and in subjects as diverse as astronauts, medical workers, atomic bomb survivors, accidentally exposed individuals, and those undergoing diagnostic or radiotherapeutic procedures, strongly suggest dose-related lens opacification at significantly lower doses. These observations resulted in a recent re-evaluation of current lens occupational exposure guidelines, and a proposed lowering of the presumptive radiation cataract threshold to 0.5Gy/year and the occupational lens exposure limit to 20mSv/year, regardless of whether received as an acute, protracted, or chronic exposure. Experimental animal studies support these conclusions and suggest a role for genotoxicity in the development of radiation cataract. Recent findings of a low or even zero threshold for radiation-induced lens opacification are likely to influence current research efforts and directions concerning the cellular and molecular mechanisms underlying this pathology. Furthermore, new guidelines are likely to have significant implications for occupational and/or accidental exposure, and the need for occupational eye protection (e.g. in fields such as interventional medicine).

Multispectral data cube acquisition of aligned images for document analysis by means of a filter-wheel camera provided with focus control

Abstract Multispectral imaging techniques are widely used to analyse and restore digital images of ancient documents degraded over time. In particular, acquisitions in infrared and ultraviolet bands can reveal information invisible by naked eye, which is not captured by conventional RGB imaging. Multispectral acquisitions are usually performed with filter-wheel cameras that mount a series of interference filters in front of the sensor to select the spectral band in which the document has to be acquired. Due to the use of different filters, the focus of the lens changes and it is necessary to adjust it manually for each filter, because such imaging systems are devoid of automatic focusing. Thus the acquired images may not be perfectly in-focus and have misalignments. In this work we present an automatic solution to acquire a multispectral data cube of aligned images that can be used in document analysis to extract and/or separate information through enhancement techniques. A custom-made motorized autofocus system controlled by software has been installed on a filter-wheel camera, which allows us to acquire in-focus images automatically at each filter changing, and a registration method based on Fourier-Mellin transform aligns these images. A preliminary calibration is performed to set the focusing of each filter with the working distance. As a result, the camera can capture images independently from the contrast of the scene, also in presence of documents with homogeneous texture. The proposed solution reduces considerably the acquisition time and offers a tool to acquire automatically the data cube to be used in further image analysis techniques. The results of experimentations are hereby presented and discussed.

Age‐related oxidation of lipids and proteins in rats' crystalline lens

AbstractPurpose estimation and comparison of age‐related intensity of oxidation of lipids and proteins of rats' crystalline lensMethods Experiments are carried out on 25 Wistar line rats males of four age groups: 5 (n=6), 12 (n=7), 24 (n=6) and 36 (n=6) of months. Homogenate of crystalline lens tissue was used. The level of the general lipids, the contents of diene and triene conjugates, level of the Schiff bases and TBA‐test were estimated. The received results were rated to amount of lipids and expressed in relative units. Extent of oxidizing proteins modification, the content of the general protein was defined. The level of oxidizing proteins modification was rated to amount of proteins. Potential possibility of oxidation was estimated by method of the induced chemiluminescence with use of Fenton's reactionResults In adult animals' crystalline lenses (12 months) the raised level of products of lipids oxidation was observed. Then, the level of trienic conjugates were decreasing in the interval of 12‐24 months. The comparative content of carbonyl derivative of proteins had tendency to decrease with age. At groups of age 12, 24 and 36 months in comparison with group of 5 months were determined the decrease of the hemiluminescence level. It corresponds to decrease of level of the medium for free radical oxidationConclusion On the basis of results, we can assume that, together with the intermolecular interaction of proteins with each other and with low‐molecular metabolites, the free‐radical processes of lipids proceeding on membranes, also contributes to formation of age‐related changes of lens in rats

The lipids of lens in the aging and in cataractogenesis

AbstractPurpose to study influence of lens's lipids on its optical propertiesMethods 40 patients at the age from 60 to 90, with cataract were examined. The lens tissue after phacoemulsification was investigated. The cataract maturity, color characteristics of lens were estimated. Laboratory researches of crystalline lens' tissue were included: researching of lipid peroxidation's level; studying of lipid peroxidation's products; researching of the higher fatty acids' compositionResults Concentration of the free oxidations' primary and secondary products were gradually decreased in about 5 times with the age. The finite products of the free oxidations had a similar tendency. The chemiluminescence level also was decreasing during the period from 50 to 70 years. In contrast to the other groups in 80 years slight increase of lipid peroxidations processes in comparison with group of 70 years, except for malonic dialdehyde was observed. When the cataract was developing in the changes of the free‐radical oxidation had differences: at initial changes in lens there was a sharp intensification of free‐radical activity and then the level of lipid peroxidation was on the high level. The polyunsaturated fatty acids and the palmitic acid had max percent of content in lens, the min – lauric and linolenic. The content of saturated and polyunsaturated fatty acids was approximately identical. When cataract was developing the composition of the higher fatty acids was changing considerably: the content of palmitic acid was increasing, the correlation factor was 0.52(R<0.05); the content of linoleic acid was decreasing, the correlation factor was ‐0.6(R<0,05)Conclusion The differences between the lipid peroxidation in the aging and the lipid peroxidation in cataractogenesis were revealed

Straylight as indication for cataract surgery

AbstractWe know that there are many sources of physiologic scatters such modified cornea (after refractive surgery, haze, dystrophies, ocular surface disease) , vitreous alterations and lens changes with the aging process inducing progressive cataract and impairing light diffusion. Nowadays, thanks to the access to scatter measurement, we might be able to assess tear film quality dynamics (with an increase in ocular surface desiccation commonly observed in old patients), but moreover we could detect early cataract at the stage of no induced visual acuity decrease but quality of vision degradation. We will present the preliminary results of a multicenter French study based on the use of the Double Pass Image Analyser (OQAS) for the potential diagnosis of cataract, on a standardized questionnaire of life and taking also account the integrity of ocular surface in addition to visual performances. The key parameter provided by this platform is the OSI (Ocular Surface that increases when scatters are in elevation (superior to 4). Our preliminary pilot results show a significant correlation between quality of life and OSI changes, suggesting that the objective measurement of light scatter might be of interest for detection of early cataract and that the consideration of quality of life (based on a basic questionnaire) should be considered in the modern new definition of cataract.

Crystallin distribution patterns in Litoria infrafrenata and Phyllomedusa sauvagei lenses

The eye lens remains transparent because of soluble lens proteins known as crystallins. For years γ-crystallins have been known as the main lens proteins in lower vertebrates such as fish and amphibians. The unique growth features of the lens render it an ideal structure to study ageing; few studies have examined such changes in anuran lenses. This study aimed to investigate protein distribution patterns in Litoria infrafrenata and Phyllomedusa sauvagei species. Lenses were fractionated into concentric layers by controlled dissolution. Water-soluble proteins were separated into high (HMW), middle (MMW) and low molecular weight (LMW) fractions by size-exclusion HPLC and constituents of each protein class revealed by 1DE and 2DE. Spots were selected from 2DE gels on the basis of known ranges of subunit molecular weights and pH ranges and were identified by MALDI-TOF/TOF MS following trypsin digestion. Comparable lens distribution patterns were found for each species studied. Common crystallins were detected in both species; the most prominent of these was γ-crystallin. Towards the lens centre, there was a decrease in α- and β-crystallin proportions and an increase in γ-crystallins. Subunits representing taxon-specific crystallins demonstrating strong sequence homology with ζ-crystallin/quinone oxidoreductase were found in both L. infrafrenata and P. sauvagei lenses. Further work is needed to determine which amphibians have taxon-specific crystallins, their evolutionary origins, and their function.

NDVI as an indicator for changes in water availability to woody vegetation

Barrier islands shrub thickets, the dominant woody community of many Atlantic coast barrier islands, are very sensitive to changes in the freshwater lens and thus, constitute a strong indicator of summer drought. NDVI was computed from airborne images and multispectral images on Hog Island (VA, USA) to evaluate summer growing season changes in woody communities for better predictions of climate change effects. Patterns of NDVI were compared year to year and monthly relative to precipitation and water table depth at the appropriate temporal scale. The highest absolute values of NDVI as well as the larger surface covered by woody vegetation (NDVI>0.5) occurred in the wet year (2004) with a bimodal distribution of NDVI values (around 0.65 and 0.9) while both dry years (2007 and 2008) showed similar values in maximum, mean and standard deviation and unimodal distributions (around 0.75) of NDVI values. Positive linear adjustments were obtained between maximum (r2>0.9) and mean NDVI (r2>0.87) and the accumulated rainfall in the hydrological year and the mean water table depth from the last rainfall event till the date of the image acquisition. The spatial variations revealed that water table depth behaved different in wet and dry years. In dry years there was a remarkable increase in mean and maximum values linearly related to water table depth. The highest slope of the adjustment in 2007 indicated a sharp response of vegetation in the driest year. Monthly series of NDVI showed the major role of lack of precipitation through July and August in 2007 with missing classes of NDVI above 0.8 and unimodal distributions in mid-late summer. Best linear fits (r2 close to 1) were obtained with rainfall at different temporal scales: accumulated rainfall in the hydrological year 2004 and accumulated rainfall in the last month previous to the date of 2007 image. Thus, in dry years productivity is closely related to water available from recent past as opposed to over the year for wet years. Good fits (r2 values higher than 0.88) were obtained between monthly decrease in water table depth and NDVI variables just in the dry year. These results demonstrate the important feedback between woody vegetation response to changes in the freshwater lens using empirical data and could apply to other systems with strong directional gradients in resources.

Age-related Changes in Vision and Required Illumination for the Elderly(<Special Issue>Learning from the Great East Japan Earthquake : Lighting for the Elderly and People with Low Vision)

We calculated equivalent illuminance levels and their ratios for young and elderly people by combining data on age-related changes of human crystalline lens and pupil size. The results reveal that effective illuminance for the elderly is a quarter of that for young people when, for energy savings, environmental illuminance is reduced to half. In addition, visibility of the elderly is lower than that of the young even though equivalent illuminance is ensured for the elderly. Finally, we showed that some considerations, such as more than doubling the illuminance of the young, may be necessary for the elderly when energy savings are conducted in public spaces.

Corneal and Crystalline Lens Dimensions Before and After Myopia Onset

To describe corneal and crystalline lens dimensions before, during, and after myopia onset compared with age-matched emmetropic values. Subjects were 732 children aged 6 to 14 years who became myopic and 596 emmetropic children participating between 1989 and 2007 in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error Study. Refractive error was measured using cycloplegic autorefraction, corneal power using a hand-held autokeratometer, crystalline lens parameters using video-based phakometry, and vitreous chamber depth (VCD) using A-scan ultrasonography. Corneal and crystalline lens parameters in children who became myopic were compared with age-, gender-, and ethnicity-matched model estimates of emmetrope values annually from 5 years before through 5 years after the onset of myopia. The comparison was made without and then with statistical adjustment of emmetrope component values to compensate for the effects of longer VCDs in children who became myopic. Before myopia onset, the crystalline lens thinned, flattened, and lost power at similar rates for emmetropes and children who became myopic. The crystalline lens stopped thinning, flattening, and losing power within ±1 year of onset in children who became myopic compared with emmetropes statistically adjusted to match the longer VCDs of children who became myopic. In contrast, the cornea was only slightly steeper in children who became myopic compared with emmetropes (<0.25 D) and underwent little change across visits. Myopia onset is characterized by an abrupt loss of compensatory changes in the crystalline lens that continue in emmetropes throughout childhood axial elongation. The mechanism responsible for this decoupling remains speculative but might include restricted equatorial growth from internal mechanical factors.

Age-related changes in the ocular lens of the albino rat

Background The eye lens is a minute organ with a complex structure that plays an indispensible role in the process of vision. Aim of the work This study was conducted to detect age-related structural changes that occur in the rat ocular lens and to correlate these changes with the development of senile cataract. Materials and methods Fifteen male albino rats were used in this study. They were divided into three groups: young, adult, and aged (1, 6, and 18 months, respectively). The animals’ lenses were removed, dissected, and processed for light and scanning electron microscopy. The width, thickness, and number of lens fibers were assessed using an image analyzer. Statistical analysis of data was carried out using analysis of variance and the Student t-test. Results In H&E-stained sections, the lens of aged rats was seen to be covered by a thick capsule and had a double layer of epithelial cells. The aged lens showed marked disorganization and vacuolation of nuclear fibers. Scanning electron microscopic study revealed irregularities of the lateral borders of the cortical fibers, folding of their surfaces, and few ball and socket interlocking patterns. The nuclear fibers showed microplicae with a decrease in their cross-sectioned areas. Statistical analysis revealed a significant increase in the number and width of the aged nuclear lens fibers and a significant decrease in their thickness, compared with younger ones. Conclusion Lens fibers undergo some structural changes as a result of aging in the form of irregularities in shape and arrangement, thinning and compaction. These changes could be correlated to age-related optical problems such as senile presbyopia and cataract.

Biochemical and Ultrastructural Changes in Lens during Aging of Wistar Albino Rats

Biochemical and Ultrastructural Changes in Lens during Aging of Wistar Albino Rats

Biochemical and Ultrastructural Changes in lens during Aging of Wistar Albino Rats

Aims: To correlate the age-related structural changes in lens with its contents of amino acids and minerals involved in its functional activity (sodium, calcium, magnesium and copper). Study Design: Experimental study. Place and Duration of Study: Department of Zoology, Faculty of Science, Mansoura University, Egypt, between June 2009 and July 2011. Methodology: One hundred male and female albino rats of the Wistar strain (Rattus norvegicus) aging 1, 6, 18, 30 & 42 months were used during experimentation. At the mentioned ages, the animals were sacrificed by diethyl ether and ocular regions were dissected and lens separated. Amino acids content were determined in both lenses of five individuals. In the other five individuals, unilateral ectomized lenses were subjected for chemical determination of calcium, sodium, cupper and magnesium. The rest lenses on the other side were fixed in 10% phosphate buffered formalin followed by 2.5% glutaraldhyde for scanning electron microscopic investigation. Statistically analysis was carried out by the help of SPSS software. Results: The estimated amino acids were altered in both sexes with advancement of aging. The lens amino acids; taurine, prolline, serine, threonine, methionine, lysine and arginine were markedly increased during aging comparing with apparent depletion of asparate, valine and methionine. The alterations in amino acid contents were parallel with increased accumulation of calcium, sodium and cupper and a depletion of magnesium content. Scanning Electron Microscopic (SEM) observations exhibited sequences of changes of the structures of lens fibers and their pattern of attachments during the advancement of aging. In the advanced aged group, the lens fibers become fragile and widely separated as a result of loosely attached of the interfibrillar junctions of the ball and Research Article British Journal of Medicine & Medical Research, 2(1): 105-121, 2012 106 socket especially at 30 & 42 month old rats. Conclusion: Aging led to alterations of lens fibers at ultrastructural levels associated with diversity of changes in their amino acids contents parallel with increase accumulation of sodium, calcium and cupper and a decrease of magnesium content. The observed findings may be attributed to the increase of advanced glycation end products initiated oxidative stress, impairing lens structure and function.

Lens proteomics: analysis of rat crystallins when lenses are exposed to dexamethasone

To identify glucocorticoid induced cataract (GIC)-specific modified crystallins and related changes, we analyzed rat crystallins and related changes in lenses exposed to dexamethasone (Dex). To carry out proteomics analyses, we separated soluble lens proteins with two-dimensional electrophoresis (2-DE) and modified crystallins were analyzed with matrix assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS). Related changes in mRNA, protein levels and morphological and functional changes of modified crystallins were also determined. Measured masses (except for γD-crystallin as the larger and cross-link form), the isoelectric points (PIs; except for βB3-crystallin as the alkalinization form) and amino acid sequences of all known rat crystallins matched previously reported data. Analysis by 2-DE indicated that αA, αB, βB3 and γD increased when lenses were exposed to 5 μM Dex; βA4 increased when lenses were exposed to 1 μM Dex and the five proteins that had the highest expressional trend were identical with the results of Q-PCR. βA3/A1 crystallin (expressional trend identical with results of Q-PCR) and the serum albumin precursor gradually disappeared when exposed to 1-50 μM Dex. Results of Western blotting, immunohistochemistry or fluorescence analysis showed that αA and αB increased most when exposed to 5 μM Dex and βA1/A3 and KI-67 decreased obviously when exposed to 1-50 μM Dex. Electron microscopy showed that the condition of the lens was better when lenses were exposed to 5 μM Dex than at other levels and cracks between the fiber cells became larger when lenses were exposed to 1-50 μM Dex. A chaperone role of α-crystallin protecting heated catalase (CAT) and the activity of superoxide dismutase (SOD), glutathione (GSH), and caspase-3 were highest when exposed to 5 μM Dex. Moreover, αA-crystallins were associated with increased phosphorylation (PI decreased). In conclusion, the proteomics analysis and related changes of rat crystallins when lenses were exposed to Dex in this study will be useful for comparison with normal lens proteins and GIC. We also provided a mechanism for GIC from a proteomics aspect based on the in vitro model.

Antioxidants Prevention of Diabetic Damage in the Organ Culture Bovine Lenses

Oxidative stress represents a mechanism which could lead to diabetic cataract. We exposed bovine lenses in culture conditions for two weeks to high glucose concentration (450 mg%) and investigated the damage to the lens and possible protection by special antioxidants - N-acetyl-L-cysteine (NAC) and the zinc complex of desferrioxamine (DFO), a selective chelator for iron. We monitored the optical quality of the lenses and the oxidation of the epithelium with dichlorofluorescein (DCF) assay, as well as the changes in lens proteins profile by 2D gel electrophoresis. Under high glucose changes in lens focal length, increased oxidation, and changes in lens crystalline were observed. NAC and Zn- DFO nearly completely protected the lenses; DFO showed only partial protection. The results demonstrated that antioxidants should be considered as treatment modality protecting the lens from high glucose damage. It is proposed that a combination of NAC and Zn/DFO could prove highly efficient.

Choice of One-Piece Intraocular Lens Power and Changes of Anterior Chamber in Sulcus Implantation due to Posterior Capsular Rupture during Cataract Surgery

Choice of One-Piece Intraocular Lens Power and Changes of Anterior Chamber in Sulcus Implantation due to Posterior Capsular Rupture during Cataract Surgery

Objective evaluation of the changes in the crystalline lens during accommodation in young and presbyopic populations using Pentacam HR system.

To quantify the changes in the lens profile with accommodation in different age groups. The Pentacam HR system was used to obtain the images of the anterior eye segment from 23 young and 15 presbyopic emmetropic subjects in unaccommodated (with an accommodation stimulus of 0.0D) and accommodated (with an accommodation stimulus of 5.0D for the young group and 1.0D for the presbyopic group) states. The phakic crystalline lens shape, including curvature of crystalline lens and central lens thickness (CLT), and the measurements of anterior segment length (ASL), central anterior chamber depth (CACD) were investigated. The anterior chamber volume (ACV) was also measured. The reduction of CACD and ACV were significant in both groups after accommodation stimulus. From the profile of anterior eye segment, a significant decrease in anterior crystalline lens radii of curvature (-2.52mm) and a mean increase in CLT (0.222mm) and ASL (0.108mm) were found in the young group with an accommodation stimulus of 5.0D. However, no statistically significant changes of CLT, ASL, or crystalline lens radii of curvature were found in the presbyopic group. Our data showed that the shallowing of anterior chamber during accommodation was caused by the forward bulging of the anterior lens surface, rather than by anterior shifting of lens position in either young or presbyopic subjects.

Contact Lens–Related Dry Eye and Ocular Surface Changes with Mapping Technique in Long-Term Soft Silicone Hydrogel Contact Lens Wearers

To evaluate ocular surface changes in long-term silicone hydrogel contact lens wearers. Thirty patients were included in this study. Twenty patients (40 eyes) using contact lenses constituted group 1 and 10 (20 eyes) volunteers constituted group 2. The duration of average contact lens usage was 7.74 ± 3.3 years. Ocular surface was evaluated by surface staining, tear film break-up time (TBUT), Schirmer I test, and conjunctival impression cytology with color-coded mapping technique and by the Ocular Surface Disease Index (OSDI). The mean break-up time was lower and staining scores were higher in group 1 (p<0.001) but Schirmer values were not significantly different from group 2 (p>0.05). The mean OSDI score was 34.59 ± 11.93 to 19.28 ± 6.7 in group 1 and 2. Increased metaplastic predominant changes of grade II and III were observed in the interpalpebral and perilimbal areas in group 1. Significant correlations were observed in TBUT, cornea staining, and grade II to grade III metaplasia ratios between duration of the lens usage and contact lens wear time in a day. Silicone hydrogel lenses produce significant changes on tear film and impression cytology of the ocular surface in long-term use.

Ultrastructural change of rabbit lens epithelial cell in the early stage of vitreous hemorrhage

Background Vitreous hemorrhage in long-term produces toxic substances and influent the metabolism of eye tissue.Lens capsule is found more thin and transparent in the eyes with chronic vitreous hemorrhage.To research the effect of vitreous hemorrhage to lens is very important for the choose of the phaco operative timing.Objective The aim of this work was to investigate the ultrastructural change of lens epithelial cells(LECs) in the eyes with experimental vitreous hemorrhage.Methods The autologous blood of 0.1 ml was intravitreally injected in the left eyes of 8 general New Zealand white rabbits,and the equal amount of phosphate buffered saline(pH7.4) was used at the same way in the right eyes.Vitreous and fundus were examined with direct ophthalmoscope on 1,3,5,9,15,20,25,30 days to assess the inflammatory response after intravitreal injection.The specimens of lens anterior capsule were obtained in 30 days after injection and the ultrastructure and apoptosis of LECs were evaluated under the transmission electron microscope. Results No obvious ocular inflammatory response was seen throughout the experimental duration,and there was no vitreous hemorrhage in the right eyes after intravitreal injection.The vitreous hemorrhage agglutinated with clear boundary in the left eyes on 1 day after intravitreal injection,and the hemorrhage turned into dark-red color on the fifth day.On the fifteenth day after injection,the hemorrhage mass became to be grey color and the vitreous liquefaction occurred in the left eyes.The hemorrhage disappeared until 25 days.But in the one month after injection of self-blood,the vitreous showed the deeper red color.The early apoptosis appeared in the LECs of the left eyes in the thirty day,presenting the enlargement and broaden of intercellular space,the decrease of mitochondria number,vacuolar change,expanse of endoplasmic reticulum and disappearance of the nuclear membrane structure. Conclusions Vitreous hemorrhage leads to the ultrastructural pathological changes of lens. Key words: Vitreous hemorrhage; Lens epithelial cell; Ultrastructure