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We report the case of a now 6-year-old girl who was born with different abnormalities in each eye. The right eye showed a total sclerocornea. At the age of 4 years we performed a perforating keratoplasty. On the left eye a large staphyloma developed. The staphyloma was excised and a cornea with a scleral rim was fixed in. This transplant became cloudy under a conjunctival flap and blepharoplasty. In addition to the clinical follow-up, histological and immun-histochemical examinations of the corneas were carried out.

Between February 1992 and March 1994, reconstruction of the fornices in 17 patients with extensive symblephara or lid fusion after most severe eye burns was performed with nasal mucosa from the inferior conchae as graft material. The time between accident and transplantation ranged from 2-64 months. All patients were followed for 6 to 31 months. Reconstruction of the fornices was achieved in 13 patients. Postoperative Schirmer-tests revealed markedly improved results. Impression cytology showed a persistence of goblet-cells and an excess of mucus. We have subsequently performed keratoplasties in 5 of these patients and are planning penetrating keratoplasties in a further 8 cases. In 4 patients, partial symblepharon formation recurred within 2-3 months after transplantation of nasal mucosa. The main advantage of nasal mucosa over buccal or labial mucosa may be the transplantation of intraepithelial goblet cells, leading to an improvement and stabilisation of the tear film.

Purpose: Severe eye burns often result in extensive necrosis of the conjunctiva and episcleral tissue. Video fluorescein angiography was performed to reveal the perfusion of the anterior eye segment after severe eye burns. Methods: A scanning laser ophthalmoscope was used for anterior segment fluorescein angiography in 12 patients (14 eyes) with severe burns grade III-IV and in 7 healthy volunteers. Results: Necrotic tissues occurred as non perfused areas and remained dark throughout the whole angiogram. In general, the borders from healthy to necrotic conjunctival tissue were sharply demarcated. Thus, the extent of scleral and lim-bal ischemia could be determined exactly. Injured vessels showed hyperfluores-cence with late leakage. Damage of the subconjunctival tissue appeared as a deep weak fluorescence in the early angiography and exhibited patchy leakage in the late angiogram. Conclusions: Anterior segment angiography provides a basis for deciding the extent of surgical debridement of necrotic tissue in the acute phase of the burn. The determination of the extent of limbal and scleral ischemia may give useful information for early plastic-reconstructive procedures.

Purpose Chemical burns with calcium containing corrosives as well as irrigation with phosphate buffer solutions after eye burns bear the risk of corneal calcification. The aim of this study was to evaluate the correlation between the occurrence of corneal calcification after chemical injuries and the usage of phosphate buffer containing local therapeutics. Methods We reviewed the data of 179 patients who have been treated in the University Eye Clinic Aachen, Germany, between 1941 and 2000. Only when the corrosive did not contain calcium and when the initial irrigating solution did not contain phosphate buffer, respectively, were patients included in the study. The cases were analyse, if the patient was treated with phosphate buffer containing eye drops/ointment during the first 7 days of hospitalization or as an out-patient, and if corneal calcification was visible by slit-lamp examination during the follow-up. Statistical analysis was performed using Fischer's exact test. Results 152 eyes were included. From 63 eyes treated with phosphate buffer containing eye drops, 31 eyes (49%) developed corneal calcification. From 89 eyes treated without phosphate buffer containing eye drops, only 23 eyes (26%) developed corneal calcification. The two-sided p-value of Fischer's exact test is 0.0036. Conclusion During follow-up after chemical eye burns, eye drops containing phosphate buffer double the risk of corneal calcification. We recommend avoiding these agents in order to prevent the burned cornea from additional opacity. Substances containing phosphate buffer are listed in this article.

Hintergrund Wahrend der Organkultur schwellen die Hornhaute stark an und mussen daher vor der Transplantation mit Hilfe eines Mediums wieder entquollen werden. Sowohl die Quellung als auch die Entquellung fuhren zu einem vermehrten Endothelzellverlust. Daruber hinaus ist das derzeit verwendete Dextran toxisch und wird in die Hornhaute aufgenommen. Ob HES als Dauerzusatz in der Organkultur vertraglich ist und hiermit auch dauerhaft der Quellung der Hornhaute entgegen gewirkt werden kann, soll in dieser Studie untersucht werden.

Purpose: To evaluate the effects of hypo-osmolar tap water and isotonic saline solution on the intracameral pH, intraocular pressure and histological changes in alkali burned rabbit eyes. Methods: Four groups of four rabbit corneas each were burned with 2 N sodium hydroxide, and then rinsed with 0.5 l or 1.5 l of saline solution or tap water, respectively. Changes in pH were monitored with an intracameral microelectrode. Intraocular pressure (IOP) was monitored by a transducer placed in the vitreous cavity. After enucleation, histology was performed. Results: The pH increased after 1.5 min following alkali application. Irrigation with different solutions affected the maximum pH levels reached. Following the tap water rinse, the maximum rise was significantly lower than after the saline solution rinse. The maximum rise following rinsing with 1.5 l of tap water showed a significant delay. The increase in IOP was 23 ± 10 mmHg without differences between the groups; the original pressure was recovered after 18 ± 9 min. Histology of the eyes revealed a significant oedema in all corneas. Other ocular structures appeared unchanged. Conclusions: The hypo-osmolarity of tap water led to remarkable corneal oedema. Enlargement of the diffusion barrier and intracorneal dilution inhibit elevated intracameral pH levels. The difference in maximum pH levels reached may influence the degree of subsequent intraocular structure injury. Therefore, the use of iso-osmolar saline solution proves to be less efficacious than tap water as an irrigation agent for ocular burns.

BACKGROUND Excessively draining fistulas may lead to enucleation when primary suture closure is not effective. In these cases preserved cadaver tissues such as sclera, fascia lata, dura mater and peritoneum have been used for patch graft repair with variable results. In this study, the clinical outcomes after transplantation of scleral patch grafts have been investigated. METHOD Twenty-eight eyes of twenty-seven patients underwent surgery with homologous scleral patch grafts for repair of excessively draining scleral fistulas after cataract surgery (n = 2), leaking filtering blebs following full-thickness filtration surgery (n = 7), large scleral perforations due to trauma (n = 7), corneo-scleral ulcerations due to severe eye burns (n = 9) or after radiotherapy of malignant melanoma (n = 3). The mean size of the rectangular grafts was 8.6 x 6.7 mm (+/- 2.8/3.1 mm). Clinical follow-up was up to 73 months (median 30 months). RESULTS Twenty-three of 28 eyes (82.1 %) showed functional closure after initial surgery without any wound complication such as patch retraction or leakage and without evidence of inflammation. In five eyes surgical revision was necessary. Two of these eyes had to be enucleated due to uncontrollable dehiscence after the second operation. Two eyes were enucleated at the patient's demand due to pain. The fifth eye showed effective closure after the second operation. CONCLUSION In our study scleral patch grafts were useful in adequately closing large corneo-scleral defects in 24 of 28 eyes (85.7 %). The antigen load and, therefore, the rejection of the scleral grafts is minimized due to the denaturation of proteins during the alcohol treatment before storage.

Chemical and thermal eye burns account for a small but significant fraction of ocular trauma. The speed at which initial irrigation of the eye begins, has the greatest influence on the prognosis and outcome of eye burns. Water is commonly recommended as an irrigation fluid. However, water is hypotonic to the corneal stroma. The osmolarity gradient causes an increased water influx into the cornea and the invasion of the corrosive substance into deeper corneal structures. We therefore recommend higher osmolarities for the initial rinsing to mobilize water and the dissolved corrosives out of the burnt tissue. Universal systems such as amphoteric solutions, which have an unspecific binding with bases and acids, provide a convenient solution for emergency neutralisation. Both conservative anti-inflammatory therapy and early surgical intervention are important to reduce the inflammatory response of the burnt tissue. In most severe eye burns, tenonplasty re-establishes the conjunctival surface and limbal vascularity and prevents anterior segment necrosis.

Background. Late secondary glaucomas after severe chemical or thermal eye burns are associated with diagnostic and surgical difficulties. Routine filtering surgery (trabeculectomy) has a low success rate. In these eyes aqueous shunt implantation and cyclophotocoagulation are alternative procedures. Patients. In our retrospective study,the records of 12 patients with 14 severe eye burns (grade IV) were analyzed. Nine eyes were treated with an aqueous shunt device (six von Denffer and three Ahmed implants). Diode laser cyclophotocoagulation (Iris Medical Instruments) was performed in five eyes.The mean time interval between surgery and accident was 88.3 months (aqueous shunt) and 32.8 months (cyclophotocoagulation). Results. The mean follow-up was 45±36 months (von Denffer implant), 38±5 months (Ahmed implant), and 11±8 months (cyclophotocoagulation). Intraocular pressure (IOP) was reduced from 39±7 to 23±6 (von Denffer implants) and from 38±3 to 8±10 (Ahmed implants). Mean IOP before treatment with cyclophotocoagulation was 33±8 and 18±2 after treatment. Systemic carbonic anhydrase inhibitors were stopped in all patients. Visual acuity deteriorated in five of nine eyes treated with aqueous shunt devices and was unchanged or better in all eyes treated with cyclophotocoagulation. Multiple re-operations were necessary after aqueous shunt implantation. Severe complications leading to failure in these eyes were encapsulated bleb in four eyes, expulsive hemorrhage in one eye, and phthisis in one eye. Cyclophotocoagulation was repeated in two eyes. Severe complications were not observed. Conclusion. IOP reduction was effective and comparable in both procedures. Because of the high incidence of severe complications after shunt surgery, we prefer cyclophotocoagulation for the treatment of intractable glaucoma after severe eye burns.

A new keratoprosthesis was used during pars plana vitrectomy in order to test the optical quality, watertightness, short-term biocompatibility and handling of the new device. The implantability was also tested, given that this keratoprosthesis might in future be left in place for several months. This Aachen keratoprosthesis (Aachen-KPro) is developed to be used as permanent implant to restore vision in corneal blind patients. Patient and methods: The Aachen-KPro was used during pars plana vitrectomy in 10 patients with opaque corneas. In four cases, trauma precipitated the ocular disease. Eye burn was the cause of corneal and retinal disorders in another four cases. One patient had a history of congenital glaucoma with myopia, and one of uveitis with corneal dystrophy. After trephination of 6.5 mm in diameter, the Aachen-KPro, composed of soft silicone rubber, was temporarily placed in the trephination hole. After completion of the vitrectomy, the Aachen-KPro was replaced by a 7 mm corneal graft. Results: Intraoperative use of the Aachen-KPro allowed uncomplicated intraoperative handling, smooth adaptation to the corneal rim in the trephination hole, and an undistorted view of the central and peripheral retina. Leakage, even during scleral depression, could be avoided by individual suturing of the scleral rim. After a follow-up period of 1–10 months, the retina was still attached in all cases. The corneal graft was clear after surgery in four eyes, and edema was found in three cases. Amnion or conjunctiva was placed over three patients’ transplants. Conclusion: We report the first temporary implantations of a new keratoprosthesis in 10 patients. Its flexibility and good optical qualities allowed control of intraoperative procedures. The outcome and prognosis of the vitreoretinal surgery and keratoplasty were related to the primary diagnosis. The Aachen-KPro has shown advantages, especially in eyes where the anterior eye segment is severely damaged by eye burn or previous surgical interventions. In the future, prolonged use of the Aachen-KPro is planned for selected eyes.

Hintergrund. Fruhere Studien haben gezeigt, dass erhohte Augeninnendruckwerte nach Keratoplastik das Endothel schadigen, sodass es in ca. 10% der Falle zu einem fruhzeitigen Transplantatversagen kommt. Ziel der vorgelegten Studie ist es, exemplarisch die besonders gefahrdeten Patientengruppen darzustellen. Material und Methoden. Es wurden 75 Patienten eines gemischten Patientengutes prospektiv 2, 4, 6, 12, 24, 36, 48 und 60 Monate nach perforierender Keratoplastik untersucht. Ergebnisse. Bei 22 der 75 Patienten wurde nach Keratoplastik ein erhohter Augeninnendruck beobachtet. Hiervon ging ein Drittel (n=7) in ein chronisches Sekundarglaukom uber. Als starkster Risikofaktor erwies sich das bereits praoperativ vorhandene Glaukom (χ2-Test p

Purpose To study metabolic changes of the human cornea during organ-culture. Morphological changes have been extensively studied, whereas changes in human corneal metabolism have not been investigated yet. Material and methods 106 human corneas were stored for 1, 7, 15, 18, 21 and 28 days in a closed-system under standard eyebank conditions. After storage, glucose, lactate, ATP, ADP and AMP concentrations were determined in each cornea. Results Glucose concentration decreased during the first two weeks with a minimum on day 15. ATP and ADP concentrations increased during the same period of time, but had their minimum later, on day 18. Lactate increased during the culture period up to day 21 and decreased thereafter. Conclusion From these data we conclude that the human cornea recovers during organ-culture, especially during the first two weeks. The changes occurring after a fortnight might be related to the artificial culture conditions. Nevertheless, the metabolic status is better than in post-mortem corneas. The changes may be partly avoided by changing the medium after at least two weeks of organ-culture.

Chronic ischemia of the retina and the optic nerve head seems of importance especially in patients with normal-tension glaucoma (NTG). The purpose of this study was to examine the retinal hemodynamics in patients with NTG. Patients: Twenty-five patients with NTG were examined (3 weeks washout period) in this study (age 58 ± 16 years). The arteriovenous passage (AVP) time and arterial and venous diameters from scanning laser fluorescein angiograms were evaluated by means of digital image analysis. Results: The AVP time in patients with NTG (2.78 ± 1.1 s) was significantly prolonged (P < 0.0001) compared with healthy subjects (1.58 ± 0.4 s). No significant correlation was found between arterial and venous diameters, intraocular pressure, blood pressure or calculated perfusion pressure and retinal arteriovenous passage time. Conclusion: Patients with NTG showed prolonged retinal passage, which could cause chronic hypoxia. This prolongation of circulation is not correlated with any of the clinical parameters. Thus, a circulatory defect might be a primary factor in the pathogenesis of NTG.

BACKGROUND Metabolic changes of the human donor cornea during organ-culture are not at all reflected by the endothelium. Therefore metabolic investigations have become of increasing interest. It was the aim of this study to determine the correlation between glucose and lactate in storage medium and within the cornea itself and to find thereby an additional parameter for glucose metabolism during organ-culture. METHODS Glucose and lactate were examined in 166 organ-culture medium samples as well as in 106 human corneas by enzymatical optical methods. Investigations were carried out after 1, 7, 15, 21 and 28 days of organ-culture. RESULTS Glucose consumption was highest during the first two weeks of organ-culture. Glucose concentrations showed a good linear correlation between medium samples and the cornea (r = 0.923). The correlation coefficient for lactate was worse (r = 0.733). CONCLUSION Glucose and lactate levels in the organ-culture medium can be used as a marker for glucose metabolism in the cornea.

Background There are two well known systems to culture human corneas prior to transplantation. First, corneal storage at 4 degrees C especially in Optisol medium. Second, organ-culture at physiological temperatures in a modified minimal essential medium (MEM). In the cold storage system the number of endothelial cells after storage might be overestimated because the damaged cells are not able to leave the monolayer. It has been supposed that the lack in energy recruitment is the main reason for that, but has not been proven yet. It was the purpose of this study to describe the energy status of the human cornea after storage in both systems. Materials and methods 32 human corneas were investigated. They were stored for 7 days in Optisol, and for 7 days in MEM plus 1 day in MEM supplemented with 5% dextran 500 and 12 days in modified MEM plus 1 day in MEM supplemented with 5% dextran 500. The endothelial cell density (ECD) as well as the hydration were determined. Glucose, lactate, ATP, ADP and AMP were measured to reflect the energy status. Results Hydration was comparable in all three groups. ECD was slightly higher in Optisol stored corneas, although the amount of damaged cells was much higher. Optisol stored corneas showed a severe anaerobic situation, especially lacate concentrations were increased. In contrast ATP and ADP concentrations were twice as high in MEM than in Optisol stored corneas. Discussion The severe anaerobic situation in Optisol stored corneas leads to a lack in energy recruitment. This reduces the ability of cell function (mitosis) and the function of the monolayer (migration, elimination). Whether these changes are reversible after transplantation has to be determined in future.

• Background: Reported here are the results of electrolyte measurements in different layers of 70 apparently normal human corneas. • Methods: Samples were examined by energy-dispersive X-ray analysis under calibrated conditions in a scanning electron microscope. The method allows the simultaneous quantitative analysis of, among others, sodium (Na), chloride (Cl), phosphorus (P) and potassium (K). The results are related to the dry weight of the analyzed samples. Four distinct layers, subepithelium, middle stroma, posterior stroma and Descemet's membrane, were analysed in each cornea. • Results: In the middle stroma we found concentrations of: sodium 0.609 ± 0.13, chloride 0.557 ± 0.115, potassium 0.058 ± 0.02 and phosphorus 0.038 ± 0.01 (mmol/kg dry weight). • Conclusion: The collation of normal electrolyte concentrations provides reference values for future studies on changes of the corneal electrolyte composition in diseased or injured eyes. The electrolyte composition of rinsing fluids or eye drops should be adjusted to that of the corneal stroma. Phosphate buffer, for example, is not a good vehicle for topical eye treatments and should be replaced by organic buffering systems.

Background Severe eye burns usually result in extensive necrosis of the conjunctiva and subconjunctival tissue. To reduce the reactive inflammatory reponse excision of the necrotic tissue is necessary. Patients and Method Between August 1990 and December 1994 fluorescein angiograms of the anterior eye segment were performed in 13 (17 eyes) patients with most severe eye burns. The angiographies were carried out 1-4 days after the accident. Conventional photo angiography was performed using a fundus camera (NF 505-AF Nikon). Results The angiograms revealed characteristic patterns that provided exact information on the perfusion of burned conjunctival and underlying tissue. It was particularly useful in the detection of clinically not recognisable subconjunctival ischemia. In addition, perfusion of the episcleral vessels and the extent of scleral ischemia could be quantified. According to the angiographic findings subtile excision of the necrotic tissue was performed and vascularized tissue was preserved. Conclusion Anterior segment angiography is a valuable method in assessing the extent of necrosis of the conjunctiva and underlying tissue and in determining scleral ischemia. It provides a basis for deciding the extent of surgical debridement of necrotic tissue in the acute phase of the burn. The quantification of limbal and scleral ischemia may give useful information for early plastic-reconstructive procedures.

Quantification of adenosine phosphates in human corneal extracts has been performed using spectrophotometry. We employed the bioluminescence technique to obtain a more sensitive assay for adenosine phosphates and to reduce the volume of the test sample.The bioluminescence assay for ATP, already known from sterility control, was modified and expanded. Standard curves were established using a standard solution with equimolar concentrations of ATP, ADP and AMP. To monitor the method, adenosine phosphates were measured in 35 human corneal extracts using both spectrophometry and bioluminescence.Linear standard curves ranging from 1 to 45 pmol were established. The two methods yielded comparable results despite the use of a basic dilution of 1:100 for the new technique.Bioluminescence provides a highly sensitive quantification of adenosine phosphates in the human cornea and facilitates an extremely detailed evaluation of the metabolic status of the cornea.

Background Corneo-scleral ulcerations and perforations are severe complications after most severe eye burns. One possibility to handle this situation is a keratoplasty with a scleral rim. This retrospective study was carried out to show the outcome after total replacement of the cornea after most severe eye burns. Patients Between 1986 and 1991 we carried out 12 kerato-plasties with a scleral rim in 9 most severely burnt eyes of 7 patients. In 9 cases this intervention was the first transplantation. In 3 eyes a re-keratoplsty had to be carried out. Results All eyes could be saved after this surgical intervention, allthough all but two transplants failed. In eight cases the transplant decompensated and/or was replaced by scar tissue. Two transplants remained clear. Visual acuity was light perception in five cases, intact light projection in two cases, 1/35 in one case because of cataract formation and 0.8 in another case at the end of the observation period. The reasons for graft failure were multifactorial. Epithelial problems were the reason for graft failure in eight cases. Two of these also showed shrinkage of the eye lids with incomplete lid closure. In six cases severe vascularisation with scar formation was observed. It is remarkable that immunoreactions occurred only in four cases. This may be due to the fact that all patients were treated systemically with cyclosporin A. In one case the transplant failed after extensive surgery of the anterior segment. Conclusion Our results show that the keratoplasty with a scleral rim can save the eye in the difficult situation of corneo-scleral ulceration or perforation. Nevertheless a visual rehabilitation could not be achieved in seven of nine cases. But all eyes were in a satisfying condition for further smaller transplants to achieve better visual acuity.

Background The prognosis of penetrating keratoplasty after severe eye burns is uncertain. Beside of immune reactions the outcome is determined by surface problems. Patients and methods Between July 1991 and October 1993 in 15 patients (16 eyes) with grade IV eye burns penetrating keratoplasties with large diameters (11-16 mm) were carried out. Cultered corneas were used with an intact epithelium. In 9 eyes hydrophilic bandage lenses (Geaflex 70, Fa. Wohlk, Kiel) were applied initially, in the remainder 7 eyes within 7 days postoperatively. Results The lens radius best suited was found out by trial, because corneal topography was not possible for many weeks. In 12 (75%) eyes the lens had to be fitted steep, with a radius from ≤8.7. A change in lens radius during the healing course was rare. The frequent use of artificial tear drops was important, because many eyes showed clinical manifestations of dry eye syndrom. Complications during soft contact lens wearing were rare. In 5 eyes microbiological examination was positive, but successfully treated. Under the protection of soft contact lenses 9 eyes maintained an intact epithelium. In the remainder eyes severe vascularisation with large persistent epithelial defects occured mostly as a consequence of immune reactions. These keratoplasties developed ongrowth of inflammatory pannus or progressive ulceration. The average of the follow-up time was 22 months. Conclusion The use of large diameter keratoplasties in combination with hydrophilic bandage lenses proved to be successfull maintain the integrity of the epithelium in these high-risk keratoplasties. The prognosis of these transplants is, however, determined by immune reactions.

The authors investigated 32 human corneal buttons of patients suffering from severe eye burns. The keratoplasties were performed in different periods after the burn and collected within five years. Grafts were followed-up until they failed because of ulceration or until rehabilitating keratoplasties were performed. Early (up to six months after the burn) and late (more than 12 months after the burn) obtained corneas showed different cellular reactions in the corneal stroma. Inflammatory cells such as granulocytes and lymphocytes decreased with increasing periods after the burn. More than 12 months after the burn, minor inflammatory cellular reactions but increasing scar formation could be found. Four out of 19 early-, two out of eight intermediate- (between six and 12 months after the burn) and one of the late performed keratoplasties failed and had to be replaced by new corneal grafts. Due to the conditions in the graft beds the explanted corneal grafts showed a cellular reaction in the stroma comparable to the previously explanted burnt corneae. Further complications occurred because of problems concerning the ocular surface. After preliminary therapeutical keratoplasties rehabilitating keratoplasties could be successfully performed in four cases between 19 and 39 months.

BACKGROUND: Persistent epithelial defects of the cornea are difficult to treat and can lead to severe complications such as melting processes. Therefore the application of a glued-on hard contact lens as an artificial epithelium has been recommended for many years, to protect the denuded corneal stroma. MATERIALS AND METHODS: This paper presents a 7-year retrospective study on the application of a hard contact lens as an artificial epithelium. 46 patients with 50 eyes were treated with this method from january 1985 to march 1992. The majority of the patients suffered from most severe burns of the whole anterior eye segment (group I: n = 29 eyes) or of the cornea alone (group II: n = 13 eyes). A smaller number of patients (group III: n = 8 eyes) presented corneal melting processes associated with other diseases. RESULTS: The patients of group II and III showed the best outcome concerning spontaneous epithelialization and prognosis for a penetrating keratoplasty. The treatment with a glued-on hard contact lens was limited by the high rate of complications (92%) in group I and II. In one third of the cases of group I these complications led to further surgical interventions (e.g. conjunctivoplasty of the globe). The results also show, that the application of a glued-on hard contact lens in patients with most severe eye burns is a long-term treatment (> one year). CONCLUSION: The poor prognosis of corneas with severe healing problems of the epithelium can be improved by the application of a glued-on hard contact lens as an artificial epithelium. In severe burns of the whole anterior eye segment however, the treatment with an early keratoplasty should be considered.

We investigated the kind of reactions that occur after injection of a PMMA lens powder into the back skin of rabbit. The lens powder was suspended in NaCl and incomplete Freund's adjuvant to reinforce the immunological reaction. The ELISA test was carried out to detect antibodies against the lens material as a whole and against the UV absorber Tinuvin in particular. We also performed histological and immunohistochemical examinations of the back skin. We did not detect antibodies against either the lens material or against Tinuvin. Histological examination showed a foreign-body or delayed allergic reaction against the lens material. Lymphocytes surrounding the PMMA were found to be mainly of the T-type, which supports the results of the ELISA test.

To evaluate the effects of hypo-osmolar tap water and isotonic saline solution on the intracameral pH, intraocular pressure and histological changes in alkali burned rabbit eyes.Four groups of four rabbit corneas each were burned with 2 N sodium hydroxide, and then rinsed with 0.5 l or 1.5 l of saline solution or tap water, respectively. Changes in pH were monitored with an intracameral microelectrode. Intraocular pressure (IOP) was monitored by a transducer placed in the vitreous cavity. After enucleation, histology was performed.The pH increased after 1.5 min following alkali application. Irrigation with different solutions affected the maximum pH levels reached. Following the tap water rinse, the maximum rise was significantly lower than after the saline solution rinse. The maximum rise following rinsing with 1.5 l of tap water showed a significant delay. The increase in IOP was 23 +/- 10 mmHg without differences between the groups; the original pressure was recovered after 18 +/- 9 min. Histology of the eyes revealed a significant oedema in all corneas. Other ocular structures appeared unchanged.The hypo-osmolarity of tap water led to remarkable corneal oedema. Enlargement of the diffusion barrier and intracorneal dilution inhibit elevated intracameral pH levels. The difference in maximum pH levels reached may influence the degree of subsequent intraocular structure injury. Therefore, the use of iso-osmolar saline solution proves to be less efficacious than tap water as an irrigation agent for ocular burns.

Background The course after severe eye burns is characterized by many complications which require a longlasting and intensive therapy. The success of treatment is menaced especially by superficial problems like persistent erosiones which occur also after keratoplasty. Patient As a cause of persistent erosions, pathological changes of Bowmans' membrane are discussed. Therefore, it was removed by PTK (phototherapeutic keratectomy) in our patient, in order to allow better adhesion of the epithelium to the deeper, less changed layers. Therapy and outcome The patient suffered from a severe burn accident of his right eye with liquid cement. After proliferations were excised twice, we had to glue on a hard contact lens as an artificial epithelium due to a persistent erosion. Later, the development of a bacterial keratitis required keratoplasty. The epithelium remained intact for eleven months, but then an erosion arose and persisted for nine months. Therefore we performed a PTK and the epithelium closed subsequently within four days. Conclusion The treatment of persistent erosions has been very difficult so far, and often procedures like artificial epithelium or even keratoplasty have been necessary. The astonishing course of our patient indicates, that PTK is a promising and less invasive therapy in these cases.

Background In most clinical centers donor material can not be obtained in neccessary amounts. Therefore corneas from long-suffering donors have to be accepted, too. It was the aim of this study to demonstrate the influence of the cause of death on the endothelial cell density of fresh human corneas. Material and Methods The endothelial cell count of 81 donor corneas was determined after preparation of the corneo-scleral disc. For all donors the premortal history was evaluated concerning the cause of death and therapy. In this manner donors were divided into five groups: sudden death, carcinoma, septicemia, renal insufficiency and diabetes mellitus. Results There were no significant differences in endothelial cell count between these five groups. Even chemotherapy and radiatio of the donor had no influence on the cell density. Conclusion It may be concluded, that clear corneas have a sufficient endothelial cell density and that the cause of death has no influence on this parameter. Therefore also corneas from donors with long-standing diseases may be accepted for transplantation

Chemical and thermal eye burns account for a small but significant fraction of ocular trauma. The speed at which initial irrigation of the eye begins, has the greatest influence on the prognosis and outcome of eye burns. Water is commonly recommended as an irrigation fluid. However, water is hypotonic to the corneal stroma. The osmolarity gradient causes an increased water influx into the cornea and the invasion of the corrosive substance into deeper corneal structures. We therefore recommend higher osmolarities for the initial rinsing to mobilize water and the dissolved corrosives out of the burnt tissue. Universal systems such as amphoteric solutions, which have an unspecific binding with bases and acids, provide a convenient solution for emergency neutralisation. Both conservative anti-inflammatory therapy and early surgical intervention are important to reduce the inflammatory response of the burnt tissue. In most severe eye burns, tenonplasty re-establishes the conjunctival surface and limbal vascularity and prevents anterior segment necrosis.

Purpose To improve the prognosis of corneal grafts in silicone-oil filled eyes of patients with severe ocular trauma by a prolonged application of the Type II Aachen-Keratoprosthesis (KPro). This application endeavors to improve post-keratoplasty prognosis by avoiding corneal endothelial dystrophy in the aphakic eye due to contact with silicone oil. Patient and Procedures The Aachen-Keratoprosthesis’ haptic was modified to allow tight contact with cells. The Type II Aachen-Keratoprosthesis was then implanted in an 18-year-old male, with previous management of bilateral corneal rupture. Rather than utilize the device as a temporary intraoperative tool, we extended the device's lifespan in the eye. Main Findings Following implantation, the patient could see hand movements up to 0.1 with best correction. After 8 weeks, vision decreased and a retroprosthetic membrane proliferated. Upon conjunctival retraction, 3 months after the initial surgery, we excised the prosthesis and performed a re-vitrectomy and corneal grafting. The silicone oil was removed. After eighteen postoperative months, the graft remained clear, the retina was completely attached, and the vision was stable: 0.1 best corrected. Conclusion This case reports the prolonged implantation and prospect of the Type II Aachen-Keratoprosthesis to be utilized as a permanent device to restore vision in the near future.

• Background: Quantification of glucose and lactate concentrations in human corneal extracts has been performed using spectrophotometry. We employed a bioluminescence technique to obtain a more sensitive assay for glucose and lactate and to reduce the volume of the test sample. • Materials and methods: The NAD(P)H bioluminescence assay (Boehringer Mannheim, Germany) was modified for glucose and lactate. Standard curves were established using a standard solution with 0.004 mM and 0.01 mM concentrations of glucose and lactate, respectively. • Results: Linear standard curves ranging from 0 to 200 pmol for glucose and from 0 to 250 pmol for lactate were established. The sample volume was reduced from 100 μl to 25 μl compared with spectrophotometry. • Discussion: The modified bioluminescence technique provides a highly sensitive quantification of glucose and lactate in the human cornea and thus reveals more details of the overall metabolic status of the tissue.

Corneas are usually stored for a maximum of approximately 30 days in European cornea banks. Although attempts are being made to prolong culture periods, data on their success are extremely limited to date. The following study was carried out to describe the capacities and limits of the established system.Thirty-seven human corneas were stored foror = 12 weeks under standard eye bank conditions [modified minimal essential medium (MEM), 31 degrees C, closed system]. Twenty-one fresh human corneas served as control. Both the adenylate nucleotides and the glucose and lactate concentrations were measured in the tissue (all cellular layers) by using the bioluminescence technique. The endothelial-cell densities also were determined.Endothelial-cell densities decreased from 2,963.4 +/- 58.7 cells/mm2 (fresh) to 2,649 cell/mm2 after 4 weeks and to 2,087 cells/mm2 after 6 weeks. Storage for periods6 weeks led to total endothelial necrosis. Biochemical studies showed improving values during the first 4 weeks and acceptable conditions foror = 6 weeks.From these data, we conclude that long-term organ culture in a closed system is limited to approximately 6 weeks and thereby confirm the clinical results of Früh and Böhnke.

• Purpose: This study was conducted to determine the elemental composition of the human cornea. Special attention was paid to corneal stroma inhomogeneity. • Methods: Seventy human corneas were examined by means of energy-dispersive X-ray analysis. Epithelium, subepithelium, middle stroma, sub-Descemet layer, Descemet's membrane and endothelium were subjected to repeated measurements. • Results: In the cellular layers the phosphorus concentrations were high [0.35 mol/kg dry weight (dw) in the epithelium and 0.403 mol/kg dw in the endothelium]. Similar concentrations were found for sulphur (0.38 mol/kg dw in the epithelium). Stromal layers showed high contents of sulphur: 0.26 mol/kg dw. The phosphorus concentration was found to be higher in the subepithelium than in the middle stroma. Sulphur concentrations were highest in Descement's membrane, followed by the subepithelium and the middle stroma. • Discussion: Nucleic acids and energy-containing phosphates explain the high levels of phosphorus in the cellular layers. The high sulphur concentrations may be related to the phosphoadenosinphosphosulfate and protein turnover in the epithelium. We interpret the inhomogeneous distribution of phosphorus in the stroma as a function of the density of keratocytes. An evalulation of all known sulphur-containing biochemical components of the stroma (0.217 mol sulphur/kg dw) corresponds to our measurements. In contrast to former results we find the corneal stroma to be an inhomogeneous structure.

The aim of this histochemical study was to demonstrate the absorption of dextran 500 and its distribution in the cornea after storage under standard eye bank conditions. Furthermore, an attempt was made to distinguish between the soluble and insoluble parts of dextran 500 absorbed by the cornea, in order to see how much dextran remains in the cornea after transplantation.Forty-nine fresh and 65 organ-cultured human corneas were investigated. The corneas were cultured for 28 days in a dextran-free medium, followed by a period of 1-14 days in a medium containing 5% dextran 500. Cryosections were stained by aqueous PAS and a modified alcoholic PAS to determine the amount of dextran.Dextran was not found in the epithelium, stroma or endothelium of fresh human corneas. By contrast, extra- and intracellular positive staining reactions were detected in corneas following storage in a medium containing dextran. Dextran 500 absorption was relatively diffuse in the epithelium after storage in a dextran medium. Initial accumulations were found in the stroma near Bowman's and Descemet's membranes and also in the central part of the cornea, as the period of culture in the medium containing dextran lengthened. We also observed interaction between the stroma and endothelium: decreasing amounts in the endothelium were followed by an increase of same in the stroma. Intracellular deposits of dextran were detected after only one day. A much greater part of the extracellular dextran than previously described was found to be insoluble.As the amount of dextran in the cornea increases over a longer storage time, we conclude that the period of storage in a medium containing dextran should be limited to four days. The fact that the cornea is saturated with dextran after seven days has been shown in further studies to interfere with mitochondrial function and may also cause severe post-operative swelling of the transplant, hence leading to a longer recovery period for the patient.

* BACKGROUND AND OBJECTIVE: In the acute stage of most severe eye burns, the primary goal is survival of the globe. Initial tissue destruction may lead to extensive necrosis of the conjunctiva and underlying tissue down to the fornices, with resulting ischemia. These circumstances may cause a polymorphonuclear cell response, with resulting corneo-scleral ulceration and early melting of the globe. To reestablish the ocular surface, Tenonplasty was performed as a plastic procedure to reconstruct the conjunctival matrix of the globe up to the limbus. * PATIENTS AND METHODS: Vital Tenon's sheets from the orbital region were prepared and advanced up to the limbus to cover the ischemic or ulcerating sclera with healthy, vascularized tissue. Fifty-nine patients with 75 severely burned eyes were treated with this procedure between 1987 and 1994. A total of 243 Tenon's flaps were prepared. * RESULTS: In all cases, scierai ulcerations were prevented or healed. Epithelialization of the advanced Tenon's sheets was complete within 21 days in 80% of the cases and in all eyes within 54 days. Primary epithelialization of the burned cornea was achieved in approximately 31% of the cases. Fornices were sufficiently deep in about 74%, but severe symblepharon formation occurred in 26% of the cases. * CONCLUSION: Tenonplasty may be an alternative surgical procedure to transplantation of autologous conjunctival or mucous grafts in restoring the conjunctival surface of the globe in severely burned eyes. [Ophthalmic Surg Lasers 1997;28:105-110.]

• Background: The presence of interleukins has been demonstrated in the cornea and other ocular tissues. Although pathogenic mechanisms are unknown, interleukins seem to be involved in inflammatory disorders of the cornea. The present study was undertaken to analyse concentrations of interleukin- Iβ (IL-1β) and interleukin-6 (IL-6) in human corneas with various clinical diagnoses. • Methods: Immediately after keratoplasty 127 explanted human corneas with various corneal diseases were snap frozen and cryosections were prepared for histological examination. Furthermore, the protein content was measured according to the method of Bradford and the concentration of IL-1β and IL-6 were determined using a specific immunosorbent test (ELISA). • Results: It was found that IL-1β and IL-6 level were clearly higher in corneas with ulcerations and distinct inflammatory signs. Lower levels of both interleukins were found in corneas with a weak expression of inflammatory signs. • Conclusions: Keratitis, keratoconus with inflammatory signs, and ulcerating processes showed higher interleukin levels than corneas with non-inflammatory disorders like scar formation, corneal dystrophy and keratoconus. The results could show that, depending on the clinical diagnosis, the inflammatory status of the cornea may be evaluated by the interleukin levels determined in the corneal tissue.

The purpose of this study was to obtain further information on the viability of organ-cultured human cornea. We thus used a specific staining method for succinate dehydrogenase (SDH), which is located in the membrane system of vital mitochondria. We examined fresh and long-term-cultured human corneas. After an initial incubation period in dextran-free culture medium, corneas were stored in a medium containing dextran. With respect to different appearances of the SDH staining, minimal essential medium without dextran seems to have a positive effect on the condition of epithelial cells. After renewal of the medium, keratocytes showed a brief improvement followed by a delayed deterioration, while the endothelial cells were severely damaged. However, best results for all three cell types were observed on the fourth day in a medium containing dextran. We therefore conclude that these corneas were best suited for transplantation.