[Infectious keratitis and corneal transplantation in a 15-year-old patient wearing contact lenses]. / Bedreiging van het oog bij contactlensgebruik.

BACKGROUND: Soft contact lens wearing increases the risk of an infectious keratitis. A patient present with a red painfull eye, in which case a corneal erosion (coloring with fluorescein) was seen by the general practitioner. It is possible that the clinical course worsens in a few days with a corneal perforation as a result. In these cases a timely referral is necessary. CASE: A fifteen year old soft contact lens wearing girl developed an infectious keratitis. Within a few days she developed a corneal perforation. As a result of an emergency transplantation within 24 hours the patient preserved her globe and her visual acuity recovered. CONCLUSION: Emergency transplantations usually have a complicated course with a high risk of re-transplantation and long-term pharmacological therapy. Such an emergency transplantation is primarily performed to preserve the globe. In the Netherlands a separate pool of emergency donor transplants is available, so that a transplantation can be performed within 24 hours.

Organ culture preservation for corneal tissue. Technical and quality aspects.

INTRODUCTION: The technical and quality aspects of organ culture as a storage method for human donor corneas are described. MATERIALS AND METHODS: Data electronically stored since 1989 of > 41,000 corneas, processed in the Cornea Bank Amsterdam, are analysed. The technical information of eye banks collected in the Directory of the European Eye Bank Association (EEBA) is used as comparison. European Union (EU) directive for tissue banking and EEBA technical guidelines are references for the quality aspects. RESULTS: Organ culture allows the storage of donor corneas up to 4-5weeks. The storage phase is followed by a generally much shorter phase of 1-7 days, to reverse the corneal swelling occurring in the first phase and to transport the tissue to the clinic. Selection of the corneas based on inspection of the endothelium after storage as well as microbiological testing of the storage solution after a quarantine period are mandatory for this technique. General agreement exists about the outline of the method, but technical variations are applied to suit local circumstances and preferences of corneal surgeons. Agreement exists about a minimum endothelial cell count as selection criterion in case the donor endothelium is meant to be grafted. The use and cutoff points of other selection parameters for the cornea, e.g. the endothelial cell mosaic, are varying. According to EU regulations, a quality management system should be installed. This way each bank is able to issue a standardized product, while the production process is monitored with quality registrations. With the clinical outcome of the graft, the quality of the selection and storage procedures is verified. With the notification of adverse reactions such as primary graft failure and endophthalmitis, minimum risks will be assessed. CONCLUSION: The organ-cultured cornea is a well-documented product concerning microbiological safety and quality of the tissue. However, variations in performance and materials and no definite cut-off points for selection do not make an organ-cultured cornea a generally standardized product. The corneal surgeons have to ascertain themselves of the safety and quality of the followed procedure. It is up to an organization such as the EEBA to formulate tissue-specific additions to the EU regulations such as training opportunities, technical guidelines and criteria based on science.

Influence of topical human epidermal growth factor on postkeratoplasty re-epithelialisation.

AIM: To test the efficacy and safety of recombinant human epidermal growth factor (hEGF) on corneal re-epithelialisation following penetrating keratoplasty. METHODS: A prospective, randomised, placebo controlled study was carried out in which patients were matched for diagnosis and received either hEGF ophthalmic solution (30 micrograms/ml or 100 micrograms/ml) or placebo in a double masked fashion. Matched pairs of patients received donor corneas from the same donor and were operated by the same surgeon on the same day. At the end of surgery all donor epithelium was removed mechanically. Patients were examined twice daily and fluorescein stained photographs were taken until the epithelium had closed. The area of the defect was measured by planimetry of the fluorescein stained defect on the photographs. RESULTS: There were no significant differences in re-epithelialisation of the donor cornea between the placebo group and the group treated with 30 micrograms/ml hEGF. Time until complete closure was slightly longer with 100 micrograms/ml hEGF compared with 30 micrograms/ml hEGF and with placebo. Mean healing rate of the epithelial defect with 100 micrograms/ml hEGF was significantly slower than in the other groups. CONCLUSION: No significant acceleration of corneal re-epithelialisation was demonstrated with the use of recombinant hEGF after penetrating keratoplasty in humans.

Reticular dystrophy of the retinal pigment epithelium and choroidal neovascularization. A fluorescein and ICGV study.

We report the clinical history of 2 patients affected with reticular dystrophy of the retinal pigment epithelium and central choroidal neovascularization. With time, spontaneous reduction of the subretinal fluid associated with consequent improvement of the visual acuity has been noted in our first case. The second patient showed a stable fibrotic subfoveal choroidal neovascularization. Conventional fluorescein angiography and indocyanine green videoangiography findings are illustrated. The differential diagnosis between other reticular pigmented lesions often associated with choroidal neovascularization is discussed.

Triple procedure; analysis of outcome, refraction, and intraocular lens power calculation.

AIMS: A total of 97 triple procedures performed over a 6 year period were studied retrospectively to determine the best approach to calculate intraocular lens power. METHODS: The cases were divided into two diagnostic categories. RESULTS: After 1 year best corrected visual acuity was 20/40 or better in 37.5% of the cases of the 'modified group'. This group consists of patients with the diagnosis Fuchs' dystrophy, non-guttate endothelial dystrophy, and Reis-Buckler dystrophy. Analysis of visual acuity was made using logMAR. A final postoperative refraction within 2 dioptres of predicted refraction was achieved in 76.5% of patients in the modified group. CONCLUSION: In future, in the absence of a keratometry, a keratometry value of 7.49 mm will be used for calculation of the power of the implant as analysed in this study.

A retrospective study on the effectiveness of oral acyclovir to prevent herpes simplex recurrence in corneal grafts.

OBJECTIVE: A retrospective study of the effectiveness of prophylactic acyclovirn to prevent recurrent infections after penetrating keratoplasty for herpetic macula. METHODS: Follow-up data of 22 patients who where treated prophilactically with oral acyclovir (2 x 400 mg for the first three months after keratoplasy) and of 19 control patients were compared. All patients were operated between 1989-1991 after being free of recurrent Herpes simplex virus (HSV) infections for a minimal period of six months. Survival was defined as the probability of being free of HSV recurrence. RESULTS: The hazard ratio calculated for the data of a 24 month follow-up was 0.66 (95%Cl: 0.47, 3.8). Survival probabilities at six months were 0.95 for the prophylaxis and 0.74 for the control group (95%Cl of the difference: 0.07, 0.37); after 12 months these proportions were 0.72 and 0.54 respectively (95% Cl: -0.13, 0.47). CONCLUSIONS: In concordance with former studies we conclude that acyclovir may be effective as a prophylaxis in this category of patients. The probability of being free from recurrence was significantly different after six months but not after twelve, possibly indicating that the period of prophylaxis was too short.

Iris claw lens: anterior and posterior iris surface fixation in the absence of capsular support during penetrating keratoplasty.

BACKGROUND: Intraocular lens implantation in eyes with pseudophakic or aphakic corneal edema and insufficient posterior capsular support presents a surgical challenge. The iris claw lens has the advantage that it can be fixated to the iris without sutures because the peripheral iris is incarcerated between the claws. METHODS: We present the results of a study with implantation of an iris claw lens in combination with penetrating keratoplasty in 19 eyes of 19 patients with pseudophakic or aphakic corneal edema which lacked posterior capsular support. The lens was fixated on the anterior iris surface (12 eyes) or posterior iris surface (seven eyes). RESULTS: Mean follow-up time was 11.8 months (7 to 21 months). All grafts remained clear. One patient was lost for follow up after 3 months. Visual acuity improved in 83% of the patients. Twenty-eight percent of the patients had a visual acuity of > or = 20/40. Complications such as pigment dispersion, glaucoma, peripheral synechiae, and lens decentration were rare. CONCLUSIONS: We feel iris claw lens implantation combined with penetrating keratoplasty is a safe alternative to achieve pseudophakia in eyes with corneal edema and inadequate posterior capsular support.

Causes of high astigmatism after penetrating keratoplasty.

We retrospectively evaluated the factors which might have caused excessive corneal astigmatism after penetrating keratoplasty (PKP) in 29 eyes, in which surgical correction of astigmatism was indicated. In 18 eyes high astigmatism (5 diopters or more) existed before suture removal probably due to graft elevation (3x), wound dehiscence (3x), wound configuration abnormalities such as ovality/overcut (8x), and a thin recipient cornea (2x). The cause was unknown in 2 eyes. In 19 eyes the astigmatism considerably increased after all sutures were removed; astigmatism increased an average of 8.8 diopters (range, 5 to 16.5 D). Ten of these 19 patients showed graft elevation, despite the fact that the sutures were only removed after an average 22.9 months. In 3 other patients the astigmatism gradually increased over the years, long after suture removal; two of these showed graft elevation. The study demonstrates the possible instability of keratoplasty wounds, the change in astigmatism after suture removal, and the late apparently spontaneous changes in astigmatism after PKP in some eyes.

Clinical comparison of grafts stored in McCarey-Kaufman medium at 4 degrees C and in corneal organ culture at 31 degrees C.

Twenty-eight paired human corneas were preserved in minimal essential medium at 31 degrees C and in McCarey-Kaufman medium at 4 degrees C. These grafts were then transplanted in pairs of patients with keratoconus who were age matched as closely as possible. These pairs received donor corneas from the same donor, so for each pair the donor age and time from death to preservation were the same. Visual acuity, central corneal thickness, and endothelial cell counts were compared. During the 1- to 2-year study period, no statistically significant difference in visual acuity, corneal thickness, or endothelial cell density was found between grafts stored in minimal essential medium and those stored in McCarey-Kaufman medium.

Mersilene (polyester), a new suture for penetrating keratoplasty.

Mersilene (polyester monofilament) seems to be suitable for penetrating keratoplasty because it is strong, shows no degradation by ultraviolet light, is insoluble, so that it can be left in situ, and offers the possibility of regulating postoperative astigmatism by suture adjustment. In 12 patients penetrating keratoplasty was performed with the combined interrupted/running suturing technique, using eight interrupted nylon 10-0 sutures and one running Mersilene 11-0 suture. The results were compared with those of 25 patients in whom eight interrupted nylon 10-0 sutures and one running nylon 11-0 suture were used. Six months after penetrating keratoplasty, no differences could be found between the two groups in keratometric astigmatism, visual acuity or slitlamp findings. In three patients postoperative adjustment of the running Mersilene suture reduced astigmatism by 50, 90 and 100% respectively. In an animal study the behaviour of Mersilene in the cornea was evaluated by slitlamp examination, histology and electron-microscopy. The tissue response to Mersilene was minimal. Considering the resemblance to nylon in clinical findings, minimal tissue response, lack of biodegradation and possibility of regulating postoperative astigmatism by suture adjustment, Mersilene seems to be a suitable material for penetrating keratoplasty.

Unusual deposits in the superficial corneal stroma following combined use of topical corticosteroid and beta-blocking medication.

Clinical observation of eight patients with superficial stromal precipitation of calcium phosphate is presented. In all cases the predisposing factors for the formation of these depositions were: epithelial defects and the combined use of topical dexamethasone phosphate or prednisolone phosphate with topical beta-blocking agents. In two patients the medication that gave rise to these precipitates was used without preservatives, suggesting that the medication itself and not the preservatives contribute to the deposits. Discontinuance of simultaneous administration of the steroids and beta-blocking agents prevented further formation of precipitates. The authors suggest an interaction between simultaneously given steroid and beta-blocking agents, giving rise to calcium phosphate precipitates when an epithelial defect is present which allows easy access to the superficial corneal stroma.

Long-term results of corneal wedge resections for the correction of high astigmatism.

We retrospectively evaluated 41 corneal wedge resections, performed for the correction of high astigmatism in 40 patients who were spectacle and contact lens intolerant. Keratometric astigmatism decreased from an average of 11.7 diopters (range 5 to 22.5 D) preoperatively to 3.5 diopters (range 0 to 10 D) postoperatively, representing a mean reduction of 8.2 D (range 0 to 16.5), or 70%. The length of follow-up averaged 11 months. Twenty-five, 15 and 9 cases had a follow-up of at least 3, 5 and 10 years, respectively. In 16 cases the keratometry readings remained stable over the years. However, in 1 case of Fuchs' endothelial dystrophy (follow-up 13 years) and 5 cases of keratoconus (follow-up 3, 4, 12, 13 and 14 years) the astigmatism gradually increased during the various follow-up periods. In 3 other cases the astigmatism gradually decreased over the years. Corneal wedge resection is an effective technique for managing high corneal astigmatism. The results remain stable over the years except in some patients with keratoconus.

Reaction of the rabbit corneal endothelium to nylon sutures. A SEM study.

Nylon and stainless steel sutures separately placed deeply into rabbit corneas by splitting the stroma for a few millimeters, without closing sutures, remained in the cornea for two, four and six weeks respectively. In contrast to the stainless steel sutures an extensive tissue reaction could be observed clinically around the nylon sutures within a few days and was still present after 4-6 weeks. On the endothelial side, covering of the nylon with fibroblast cells took place very slowly, this in contrast with stainless steel. Irritation of the tissue and an oedematous appearance of the endothelium around the nylon suture was the result. At first a kind of collagen network, often mixed with inflammatory cells, was deposited on the nylon material before fibroblast cells could grow in. Covering of the stainless steel started quite soon after implantation, without preliminary deposition of collagen material. The reason for this phenomenon must be sought in the high free surface energy of the stainless steel, which attracts cells, in contrast to nylon which has a very low free surface energy.

Comparison of the reaction of the cornea to nylon and stainless steel sutures: an animal study.

In 11 rabbits a comparison was made between the reactions of the cornea to nylon and to stainless steel sutures, macroscopically and by means of scanning electron-microscopy (SEM). Macroscopically, the wounds sutured with steel thread showed much less reaction than the wounds sutured with nylon. Vascularization was never encountered in the wounds sutured with steel thread. SEM examination also showed clear differences, which became noticeable within a short time. Both on the suture and round the opening in the cornea extensive deposits of material are seen within a short time (1 week) in the case of nylon, in the case of stainless steel this reaction is much less marked. A few weeks later deposits also appear on the steel thread, but these have a different composition and contain no material suggestive of an inflammatory reaction.

Correlation between NMR scans of extraocular muscles and clinical symptoms in Graves' ophthalmopathy.

In an NMR study of the orbits of patients with Graves' ophthalmopathy a high degree of correlation was found between the severity of the clinical picture and the relative increase in muscular volume in the retrobulbar space.

Stainless steel as suturing material in human- and rabbit corneas: a SEM-study.

Stainless steel wire, dia. 50 microns, was used as suturing material in rabbit corneas for periods of 1.5, 3 and 7 months respectively, in order to test its inertness and acceptance by the corneal tissue. One clinical case of stainless steel wire used for fixation of an I.O.L.-implantation, after a 5-year residence in the eye, is reported as well. After 1.5 months' residence, the suture margins were well covered with tissue containing irregularly shaped endothelial cells, some fibroblastic-type cells and various kinds of collagenous fibre material. The buckled surface was partly covered with a very thin membrane of collagenous material, strands of collagenous fibres and a few fibroblastic-type cells. After 3 months' residence the buckle was almost completely covered with an endothelial cell layer. The individual cells had a somewhat irregular hexagonal shape. At a few local sites closure was still progressing, with filopodia and other collagenous matter generated by neighbouring cells on top of previously deposited Descemet's membrane. After 7 months' residence, the buckle was completely covered with normal endothelium. The fixation suture in the human case showed perfect acceptance by the corneal tissue.