The anti-scarring role of Lycium barbarum polysaccharide on cornea epithelial-stromal injury.

PURPOSE: Cornea epithelial-stromal scarring is related to the differentiation of fibroblasts into opaque myofibroblasts. Our study aims to assess the effectiveness of Lycium barbarum polysaccharide (LBP) solution as a pre-treatment in minimizing corneal scarring. METHODS: Human corneal fibroblasts were cultured in a three-dimensional collagen type I-based hydrogel in an eye-on-a-chip model. Fibroblasts were pre-treated with 2 mg/mL LBP for 24 h, followed by another 24-h incubation with 10 ng/mL transforming growth factor-beta 1 (TGF-ß1) to induce relevant physiological events after stromal injury. Intracellular pro-fibrotic proteins, extracellular matrix proteins, and pro-inflammatory cytokines that involved in fibrosis, were assessed using immunocytochemistry and enzyme-linked immunosorbent assays. RESULTS: Compared to the positive control TGF-ß1 group, LBP pre-treated cells had a significantly lower expression of alpha-smooth muscle actin, marker of myofibroblasts, vimentin (p < 0.05), and also extracellular matrix proteins both collagen type II and type III (p < 0.05) that can be found in scar tissues. Moreover, LBP pre-treated cells had a significantly lower secretion of pro-inflammatory cytokines interleukin-6 and interleukin-8 (p < 0.05). The cell-laden hydrogel contraction and stiffness showed no significant difference between LBP pre-treatment and control groups. Fibroblasts pretreated with LBP as well had reduced angiogenic factors expression and suppression of undesired proliferation (p < 0.05). CONCLUSION: Our results showed that LBP reduced both pro-fibrotic proteins and pro-inflammatory cytokines on corneal injury in vitro. We suggest that LBP, as a natural Traditional Chinese Medicine, may potentially be a novel topical pre-treatment option prior to corneal refractive surgeries with an improved prognosis.

Effects of Achillea millefolium on cisplatin induced ocular toxicity: an experimental study.

Aim: Cisplatin is a widely used and highly effective anti-cancer agent and one of the limiting side effects of cisplatin is ocular toxicity. Achillea millefolium, also known as yarrow, is a plant that has been used for many years to treat various health problems including chemotherapy-related toxicities. Methods: The present investigation was designed to evaluate the biochemical, molecular and histopathological effects of Achillea Millefolium on cisplatin-induced oxidative and inflammatory ocular damage in rats. Twenty-four adult male rats were assigned randomly to four groups (n = 6) as (1) control, (2) cisplatin (7 mg/kg, intraperitoneally), (3) Cisplatin + Achillea millefolium (200 mg/kg, orally for 14 consecutive days), (4) Cisplatin + Achillea millefolium (400 mg/kg, orally for 14 consecutive days). Levels of total antioxidant capacity and total oxidant status, SOD, MDA, IL-1ß, and IL-10 were measured in ocular tissue. The mRNA expressions of TNF-α, nuclear factor kappa B and Caspase-3 were evaluated. Also, ocular sections were evaluated histopathologically.Results: Achillea Millefolium upregulated ocular antioxidant enzymes and downregulated inflammation. The SOD activity and total antioxidant capacity increased whereas total oxidant status and MDA levels decreased significantly at high dose group. High dose Achillea millefolium treatment reduced the IL-1ß concentrations, whereas IL-10 levels increased significantly in that group. Moreover, we observed that Achillea millefolium restored ocular histopathological structure and significantly suppressed apoptosis by reducing the expression of Caspase-3.Conclusion: Collectively, our results suggest that Achillea millefolium have protective effects against cisplatin-induced ocular toxicity and is a promising adjuvant therapy with the potential to prevent cisplatin related ocular toxicity.

Progesterone Application to the Rat Forehead Produces Corneal Antinociception.

Purpose: Ocular pain and discomfort are the most defining symptoms of dry eye disease. We determined the ability of topical progesterone to affect corneal sensitivity and brainstem processing of nociceptive inputs. Methods: Progesterone or vehicle gel was applied to the shaved forehead in male Sprague Dawley rats. As a site control, gel also was applied to the cheek on the side contralateral to corneal stimulation. Corneal mechanical thresholds were determined using the Cochet-Bonnet esthesiometer in intact and lacrimal gland excision-induced dry eye animals. Eye wipe behaviors in response to hypertonic saline and capsaicin were examined, and corneal mustard oil-induced c-Fos immunohistochemistry was quantified in the brainstem spinal trigeminal nucleus. Results: Progesterone gel application to the forehead, but not the contralateral cheek, increased corneal mechanical thresholds in intact and lacrimal gland excision animals beginning <30 minutes after treatment. Subcutaneous injection of the local anesthetic bupivacaine into the forehead region before application of progesterone prevented the increase in corneal mechanical thresholds. Furthermore, progesterone decreased capsaicin-evoked eye wipe behavior in intact animals and hypertonic saline evoked eye wipe behavior in dry eye animals. The number of Fos-positive neurons located in the caudal region of the spinal trigeminal nucleus after corneal mustard oil application was reduced in progesterone-treated animals. Conclusions: Results from this study indicate that progesterone, when applied to the forehead, produces analgesia as indicated by increased corneal mechanical thresholds and decreased nociceptive responses to hypertonic saline and capsaicin.

Evaluation of Prophylactic Corticosteroid Eye Drop Use in the Management of Corneal Abnormalities Induced by the Antibody-Drug Conjugate Mirvetuximab Soravtansine.

PURPOSE: Reversible, low-grade ocular adverse events (AE) are associated with administration of mirvetuximab soravtansine, a folate receptor alpha (FRα)-targeted antibody-drug conjugate undergoing phase III clinical evaluation in platinum-resistant ovarian cancer. This study investigated the underlying mechanisms of ocular toxicity and evaluated primary prophylactic use of corticosteroid eye drops in patients receiving mirvetuximab soravtansine. PATIENTS AND METHODS: Target expression in the human eye was determined by IHC. The ocular toxicity profile of mirvetuximab soravtansine was assessed preclinically using Dutch-Belted rabbits. In a phase I clinical study, patients with ovarian cancer were treated with 6 mg/kg mirvetuximab soravtansine intravenously once every 3 weeks, including one expansion cohort with corticosteroid eye drops administered daily for the first 10 days of each treatment cycle. RESULTS: FRα expression was absent from human corneal tissues. Ocular abnormalities in the rabbit eye appeared phenotypically consistent with off-target effects on the cornea. Forty patients were enrolled in the expansion cohort. Reversible grade 1 or 2 blurred vision and keratopathy occurred in 16 (40%) and 12 (30%) patients, respectively; no grade 3/4 ocular events were observed. Compared with those patients who did not receive primary prophylaxis, corticosteroid eye drop use resulted in fewer dose reductions (5% vs. 15%) and none discontinued due to ocular AEs. CONCLUSIONS: Preclinical modeling was predictive of the corneal-related symptoms seen in some patients dosed with mirvetuximab soravtansine. Primary prophylactic use of topical corticosteroid eye drops resulted in a trend toward symptomatic improvement and a reduction in ocular AE-related dose modifications in patients treated with mirvetuximab soravtansine.

Microbiologic Examination of Bandage Contact Lenses Used after Corneal Collagen Cross-linking Treatment.

PURPOSE: To investigate the agents of bacterial contamination of contact lenses after corneal collagen cross-linking (CCL), and to present the possible changes of ocular flora after riboflavin/ultraviolet A. METHODS: Seventy-two contact lenses of patients who underwent CCL and 41 contact lenses of patients who underwent photorefractive keratectomy (PRK) as control group were enrolled to the study. After 48 h of incubation, broth culture media was transferred to plates. Samples were accepted as positive if one or more colony-forming units were shown. RESULTS: There were positive cultures in 12 (16.7%) contact lenses in the CCL group and 5 (12.2%) had positive cultures in PRK group. Coagulase-negative staphlycocci (CNS) were the most frequent microorganism. Alpha hemolytic streptococci and Diphteroid spp. were the other isolated microorganisms. CONCLUSIONS: Bacterial colonization can occur during and early after the CCL procedure in epithelial healing. To prevent corneal infections after the treatment, prophylactic antibiotics should be prescribed.

Hypercholesterolemia-induced ocular disorder: Ameliorating role of phytotherapy.

The ocular region is a complex structure that allows conscious light perception and vision. It is of ecto-mesodermal origin. Cholesterol and polyunsaturated fatty acids are involved in retinal cell function; however, hypercholesterolemia and diabetes impair its function. Retinal damage, neovascularization, and cataracts are the main complications of cholesterol overload. Dietary supplementation of selected plant products can lead to the scavenging of free reactive oxygen species, thereby protecting the ocular regions from the damage of hypercholesterolemia. This review illustrates the dramatic effects of increased cholesterol levels on the ocular regions. The effect of phytotherapy is discussed in relation to the different regions of the eye, including the retina, cornea, and lens.

Dietary α-lipoic acid prevents UVB-induced corneal and conjunctival degeneration through multiple effects.

PURPOSE: This study investigated the effects of dietary α-lipoic acid (α-LA) against ultraviolet B (UVB)-induced corneal and conjunctival degeneration in a mouse model. METHODS: Female CBA mice were randomly divided into five study groups, including blank control, UVB without α-LA, and UVB with dietary α-LA at 1, 10, and 100 mg/kg body weight. Following UVB exposure, corneal surfaces were assessed along with immunohistochemistry for nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2), malondialdehyde (MDA) accumulation, and P63⁺ basal cell distribution. Matrix metalloproteinase (MMP)-2 and MMP-9 activities were determined by gelatin zymography. ELISA assay was performed to confirm the findings of immunohistochemistry for NF-κB, COX-2, and MDA, along with the levels of TNF-α and IL-6. Tear production and goblet cell density were determined after tear strip assay and periodic acid Schiff staining, respectively. RESULTS: The results showed that UVB irradiation caused corneal surface damage, polymorphonuclear leukocyte infiltration, and loss of P63⁺ basal cells. Dietary α-LA ameliorated the UVB-induced corneal damage while simultaneously reducing MDA accumulation and maintaining P63⁺ basal cell survival. NF-κB-p65, COX-2, TNF-α, IL-6, and MMP-9 activity were all reduced by dietary α-LA. In addition, α-LA helped to reverse aqueous tear reduction, conjunctival squamous epithelium metaplasia, and goblet cell loss after UVB exposure. CONCLUSIONS: Dietary α-LA can prevent UVB-induced corneal damage and can be used as a prophylactic agent prior to excessive UVB exposure.

Minimising corneal scarring from the use of harmful traditional eye remedies in developing countries.

Corneal scarring is the fourth largest cause of blindness globally, and a much more prominent factor in developing countries. Blindness from corneal scarring is largely a preventable phenomenon, and is capable of causing significant morbidity that can last for a lifetime. A significant proportion of these cases are caused by the use of harmful traditional eye medicines/remedies, and are used and prescribed by friends, relatives and traditional healers, with widespread use especially in developing countries. Use of traditional remedies can also cause harm indirectly by causing delays before seeking medical treatment. Reducing corneal scarring from the use of harmful traditional medicine is through a combination of approaches with the key strategies being community diagnosis, education, participation, and intervention, with provision of basic eye care integrated into the primary health care of the community. Collaboration with traditional healers in the community is also another approach that has been found to be useful.

Successful treatment of Stevens-Johnson syndrome with steroid pulse therapy at disease onset.

PURPOSE: To evaluate the visual prognosis of patients with Stevens-Johnson syndrome (SJS) and its severe variant, toxic epidermal necrolysis (TEN), followed by general and topical high-dose corticosteroids administration from disease onset. DESIGN: Prospective, observational case series. METHODS: Between May 1, 2003 and June 30, 2005, we enrolled 5 patients with SJS or TEN with ocular complications at the acute stage. Intravenous pulse therapy with methylprednisolone (steroid pulse therapy; 500 or 1000 mg/day for 3 to 4 days) was initiated within 4 days from disease onset. Topically, 0.1% betamethasone was applied over 5 times daily for at least 2 weeks. Visual acuity (VA) and slit-lamp microscopic appearance 1 year from disease onset were evaluated. RESULTS: At the first examination, corneal or conjunctival epithelial defects and pseudomembranous conjunctivitis were present in all cases. Skin eruptions dramatically improved after steroid pulse therapy. Although ocular inflammation increased for several days, pseudomembranes disappeared and corneal and conjunctival epithelium regenerated within 6 weeks. At the chronic stage, all eyes had clear corneas with the palisades of Vogt (POV), implying the presence of corneal epithelial stem cells. Best-corrected VA was 20/20 or better in all eyes. Five eyes showed superficial punctate keratopathy. No eye had cicatricial changes except for 1 with slight fornix shortening. No significant adverse effects of steroid occurred during all clinical courses. CONCLUSIONS: Steroid pulse therapy at disease onset is of great therapeutic importance in preventing ocular complications. Topical betamethasone also shows great promise for preventing corneal epithelial stem cell loss in the limbal region and cicatricial changes.

Behaviour modification in the management of chronic habits of abnormal eye rubbing.

OBJECTIVES: To describe how and why many keratoconus patients do not comply with strong advice to control chronic habits of abnormal rubbing. To outline a behaviour modification approach for controlling chronic habits of abnormal rubbing. METHODS: Common reasons for chronic habits of abnormal rubbing have been reviewed as a basis for specifying a behavioural modification approach to habit reversal. RESULTS: The methods described are organized into the classic behavioural modification structure of: (1) habit awareness, (2) competing responses, (3) development of motivation, and (4) social support. This structure is supported by the application of social influence principles to achieve optimum compliance. CONCLUSIONS: The use of take-home written information in the form of an Abnormal Rubbing Guide is the basis for the development of motivation. Family social support is based upon a widening of the responsibility for avoiding eye rubbing to all family members. Some patients will need minimal application of these principles with patient education being sufficient intervention to achieve habit reversal. For patients with strong provocation to rubbing and/or by having a well established rubbing habit, a greater exposure to the habit reversal program described is indicated. Successful habit reversal may slow the rate of ectasia progression. Prophylactic application of the methods described for patients who are at risk for developing keratoconus, or post-laser assisted in situ keratomileusis keratectasia, may show that some forms of keratectasia are preventable.

[Phototherapeutic keratectomy. Undesirable effects, complications, and preventive strategies]. / Phototherapeutische Keratektomie (PTK). Unerwünschte Wirkungen, Komplikationen und Vermeidungsstrategien.

The conceptual advantage of phototherapeutic keratectomy (PTK) include the option to remove diseased tissue on a micrometer scale. Although less invasive than other forms of corneal surgery, it remains a surgical procedure which carries inherent risks. In phototherapeutic indications this risk is higher than in otherwise healthy eyes undergoing photorefractive surgery. Potential general complications include wound-healing problems, infection, inflammation, or a recurrence of the underlying disease. More specifically, PTK is associated with unwanted refractive changes, such as a hyperopic shift or an irregular astigmatism. In this review, we discuss these problems along with prevention and treatment strategies in detail.

The protective effect of alpha-lipoic acid against oxidative damage in rabbit conjunctiva and cornea exposed to ultraviolet radiation.

PURPOSE: The purpose of this study was to determine the protective effect of alpha-lipoic acid against oxidative damage in rabbit conjunctiva and cornea exposed to ultraviolet radiation. METHODS: 20 rabbits weighing 2,500- 3,000 g were used, and we divided them into 4 groups with 5 randomly selected rabbits. The rabbits were exposed to 2 J/cm(2)/h of ultraviolet A radiation (UVA) in the range of 320-405 nm for 12 h per day within 90 days. The control group did not undergo any procedure, the UVA group was only exposed to UVA radiation. The PUVA group was treated with 8-methoxypsoralen and UVA. The alpha-lipoic acid group was administered 8-methoxypsoralen + UVA + alpha-lipoic acid. At the end of 90 days, the rabbits were killed by decapitation, and the eyes were enucleated. Both eyes of each rabbit were used for biochemical evaluation. Conjunctival and corneal free malondialdehyde (MDA), glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) levels were compared among the groups. RESULTS: Conjunctival free MDA levels were lower in the alpha-lipoic acid group compared with the UVA and PUVA groups (p < 0.05, p < 0.001, respectively). Both conjunctival SOD levels (p < 0.05, p < 0.01, respectively) and conjunctival GSH-PX levels (p < 0.01, p < 0.001, respectively) were higher in the alpha-lipoic acid group compared with other groups. Corneal free MDA levels were lower in the alpha-lipoic acid group compared with the UVA and PUVA groups (p < 0.01, p < 0.001, respectively). Both corneal SOD levels (p < 0.01, p < 0.01, respectively) and corneal GSH-PX levels (p < 0.01, p < 0.01, respectively) were higher in the alpha-lipoic acid group compared with the other groups. CONCLUSION: alpha-Lipoic acid which is considered as potent antioxidant protects the eye from the damaging effect of ultraviolet exposure.

[Protection of cornea against proteolytic damage. Experimental study of procyanidolic oligomers (PCO) on bovine cornea]. / Protection de la cornée contre l'effet des protéases. Etude expérimentale d'oligomères procyanidoliques (OPC) sur la cornée bovine.

AIM OF THE STUDY: The purpose of this work was the development of an antiprotease treatment for the cornea and later for other ocular tissues. Indeed, many proteases participate in various ocular pathologies and no really effective treatments are currently available. METHODS: We worked on bovine corneas in organ cultures, incubated in the presence and absence of bacterial collagenase. We used procyanidolic oligomers from grape seeds (PCO) as the antiproteolytic agent, added to the cultures in two different concentrations. RESULTS: The corneas incubated in the presence of collagenase were quickly attacked and their degradation was practically complete after 24 hours. With the low concentration used (0.066 mg/ml), proteolysis was only slightly inhibited. With the higher concentration of PCO (1 mg/ml), the collagenolysis was completely prevented and the corneas were completely preserved. CONCLUSION: These results show that the protective effect of the PCO against proteolytic attack, demonstrated previously on other tissues, proved to be effective also for the cornea in vitro. An adequate method of administration in clinical practice must now be developed in order to obtain an effective clinical antiproteolytic treatment.

Mitomycin C reduces corneal light scattering after excimer keratectomy.

PURPOSE: To evaluate the effect of intraoperative mitomycin C (MMC) on corneal light scattering after excimer laser keratectomy. METHODS: Phototherapeutic keratectomy (PTK) was performed in 24 rabbit eyes. After 40-microm epithelial ablation, animals were divided into three groups. In group 1, filter paper discs soaked with MMC (group 1A, 0.5 mg/mL; group 1B, 0.25 mg/ml) were applied for 1 minute. In group 2, annular filter papers soaked with MMC (group 2A, 0.5 mg/mL; group 2B, 0.25 mg/mL) were applied for 1 minute. Controls received vehicle only (group 3). Six-millimeter diameter 100-microm deep PTK was performed. Corneal light scattering was measured weekly from 1 to 6 weeks, at 10 weeks, and at 8 and 13 months using a scatterometer. A corneal light scattering index (SI) ranging from 0 to 10 was calculated; SI of 1 represents normal scattering. RESULTS: A statistically significant decrease in mean SI was noted in group 2A (annular MMC 0.5 mg/mL; p<0.05) as compared with the control group at 2 weeks. At 10 weeks, SI approached baseline levels in group 2 and the control group but showed significant increase in group 1 (MMC disc; p < 0.05). At 8 and 13 months, SI showed no statistical differences between groups. CONCLUSIONS: Controlled application of 0.5 mg/mL MMC in the corneal midperiphery transiently reduces corneal light scattering after excimer keratectomy in this rabbit model.

Randomized clinical comparison of Healon GV and Viscoat.

PURPOSE: To compare the ability of Healon GV (sodium hyaluronate 1.4%) and Viscoat (sodium chondroitin sulfate 4.0%-sodium hyaluronate 3.0%) to protect the corneal endothelium during endocapsular phacoemulsification and foldable intraocular lens (IOL) implantation. SETTING: A small ophthalmology group practice. METHODS: One hundred forty patients were randomized, 70 per group, in a prospective, partially masked study of cataract surgery using Healon GV or Viscoat. One ophthalmologist performed all surgery. Primary outcome variables were the 2 week postoperative changes in corneal thickness, endothelial cell density, mean endothelial cell size, and endothelial cell hexagonality. Several secondary variables were measured, and an analysis of the statistical power of the study was performed. RESULTS: There were no statistically significant differences between groups in terms of age (P = .856), cataract density (P = .117), preoperative best corrected visual acuity (BCVA) (P = .892), postoperative BCVA (P = .969), amount of viscoelastic material used during surgery (P = .444), amount of irrigating solution used (P = .125), or phacoemulsification time (P = .088). It took longer to remove the Viscoat than the Healon GV (P < .001), and total operating time for the Viscoat group was longer (P < .001). Two weeks after surgery, there were no significant differences between groups in corneal thickness (P = .362), endothelial cell density (P = .351), or mean endothelial cell size (P = .610). However, Viscoat preserved the hexagonal shape of endothelial cells slightly better than Healon GV (P = .043). The study had sufficient power to detect clinically significant differences in corneal thickness, endothelial cell density, and endothelial cell size. CONCLUSIONS: Healon GV and Viscoat were comparable in their ability to protect the corneal endothelium during endocapsular phacoemulsification and foldable IOL implantation. Results may vary, however, if phacoemulsification is performed anterior to the iris plane.

Changing patterns of corneal disease and associated vision loss at a rural African hospital following a training programme for traditional healers.

AIMS/BACKGROUND: Use of African traditional eye medicines (TEM) is associated with the presence of corneal disease, delay in presentation, and vision loss. An interactive training programme was conducted with traditional healers in Chikwawa District, Malawi and changes in the pattern of corneal disease assessed in patients presenting to the district hospital after the training. METHODS: All patients presenting to the district hospital with corneal disease for a 15 month period before intervention and a 12 month period after intervention were enrolled in the study. Interviews and examinations were carried out by the same person using a standardised, pretested form. RESULTS: Among the 175 pre-intervention and 97 post-intervention patients, delay in presentation improved only slightly. Blindness among patients reporting the use of TEM decreased from 44% to 21%; bilateral corneal disease in patients using TEM decreased from 31% to 10%. Multivariate analysis demonstrates that poor vision in corneal disease patients continues to be associated with TEM use and distance from the district hospital. CONCLUSION: As there were no other relevant eye health programmes in the district it is believed that this collaborative eye care programme with the traditional healers was likely to have been responsible for many of the changes in the pattern of corneal disease in the district. Although the changing patterns are encouraging and are likely to improve with additional collaboration, distance to a district hospital will continue to be a barrier to timely use of Western eye care services.

Xerophthalmia, keratomalacia and nutritional blindness.

Vitamin A deficiency remains a major cause of pediatric ocular morbidity. Over five million children develop xerophthalmia annually, a quarter million or more becoming blind. It is also a major pathway for measles-associated blindness, particularly in Africa. Treatment is practical and inexpensive, based upon the oral administration of 200,000 IU vitamin A on two successive days, at a cost of 10 cents U.S. Given the potential rapidity of corneal necrosis (keratomalacia) and the relative inaccessibility of health services to those at greatest risk, prevention is probably more important than treatment. Oral administration of high dose supplements (2000,000 IU every 3 to 6 months), vitamin A fortification of commonly consumed items, or best of all, increased dietary intake of natural sources of vitamin A will reduce the number of needlessly blind young children. Given recent evidence that vitamin A deficiency greatly increases overall mortality, even among children without evidence of xerophthalmia, the same prophylactic regimen may improve child survival by 35% or more.

[Does a iatrogenic damage caused by dacryography exist?]. / Esistono danni iatrogeni da dacriografia?

This study was aimed at investigating the changes in corneal epithelium caused by dacryocystography. Such changes can be either chemical--from iodate contrast media (iodized oil and water-soluble non-ionic cm)--or physical--from needle or catheter. Twenty-five patients (50 eyes) were studied using BUT, Schirmer tests, biomicroscopy, and pachymetry. Follow-ups immediately after dacryocystography demonstrated superficial keratitis, which was less severe with water-soluble non-ionic cm. Such lesions were hardly ever observed in patients who had been treated with dacriosol ointment on the cornea just before the X-ray exam. Follow-ups at 24 hours showed the superficial keratitis to have disappeared in all patients, independent of the kind of cm employed and of the ophthalmic ointment applied to the cornea.

Biochemical studies on the use of sodium hyaluronate in the anterior eye segment. IV. The protective efficacy of the corneal endothelium.

We devised an apparatus to add constant mechanical force to the corneal endothelium, and the protective efficacy of sodium hyaluronate to the corneal endothelium was determined quantitatively using an image analyzer. When the corneal endothelium was coated with a 1% solution of 800K or 2150K sodium hyaluronate, the damaged area was significantly less than cases having a coating with a 1% solution of 200K sodium hyaluronate or phosphate buffered saline which was the solvent of sodium hyaluronate. The water uptake of damaged cornea was also investigated using tritiated water. The cornea coated with 800K or 2150K sodium hyaluronate showed the same water uptake as the normal cornea, but the cornea coated with 200K sodium hyaluronate or phosphate buffered saline showed a significantly higher uptake. These results suggest that a 1% solution of 800K or 2150K sodium hyaluronate protects the corneal endothelium from mechanical damages.