[Recurrent bilateral corneal erosions and opacities in corneal stroma. Pre-Descemet dystrophy in X chromosome recessive ichthyosis].
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Adult↗
Biomedical subjects
G Geerling
Publications and source records attributed to G Geerling.
Costs and gains of complex procedures to rehabilitate end stage ocular surface disease.
BACKGROUND: The management of patients with end stage ocular surface disease sometimes requires extensive surgical treatment that can only be provided by specialised ophthalmology. The authors discuss the costs and gains of such complex techniques based on a case of bilateral corneal blindness secondary to Stevens-Johnson syndrome. METHODS AND RESULTS: Despite multiple lid surgery for trichiasis and repeated corneal grafting for perforations a white female patient became bilaterally blind at the age of 29 years. She also suffered from disabling discomfort in the right dry eye. At the age of 52 a two stage osteo-odonto-keratoprosthesis achieved visual rehabilitation in the left eye and microvascular transplantation of an autologous, submandibular gland resulted in sufficient lubrication to alleviate her severe discomfort in the right eye. As a result of these procedures she was able to take up a regular job again. The total costs of rehabilitation were pound 13 661 which compare with annual gains and regains for society of pound 13 497. An additional pound 4625 was saved annually in guide dog costs. CONCLUSION: This estimate shows that despite the expense of these complex techniques gains are made well within the second year after rehabilitation. In view of the benefit in quality of life for the patient and monetary savings for society these procedures should be funded by national health services at specialist centres.
Adult↗
Requirements concerning antiseptics for periorbital, orbital and intraorbital application. Local tolerance.
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Animals↗
Autologous serum eyedrops for dry eyes and epithelial defects: clinical and in vitro toxicity studies.
BACKGROUND/AIMS: Autologous serum drops have been reported to be beneficial in keratoconjunctivitis sicca (KCS) and persistent epithelial defects (PED). A clinical pilot study was carried out to examine these potential uses and in vitro toxicity testing on corneal epithelial cell cultures was performed to compare the effect of serum drops with unpreserved hypromellose (hydroxypropylmethylcellulose 0.3%). METHODS: Patients with KCS and PED, unresponsive to conventional treatment were recruited. Patients were examined before treatment, at 1 and 2 weeks after initiation, and then 2 weekly until treatment ceased. Symptoms were assessed at each visit. Clinical examination included Schirmer's test without anaesthesia, rose bengal staining, and fluorescein staining. Epithelial defects were measured with the slit beam. In the laboratory, cultured human corneal epithelial cells were exposed to serum drops and hypromellose, and their viability evaluated with fluorescent viability staining (Calcein AM ethidium homodimer) and an ATP assay. RESULTS: Autologous serum was used in 15 eyes of 13 patients with PED and 11 eyes of nine patients with KCS. In two patients serum drops were started after penetrating keratoplasty (PK). The PKs were performed for perforations secondary to PEDs. Of the 15 eyes with PED, nine healed at a mean of 29 days and six failed. The mean duration of PED before the use of serum drops was 48.2 days. Of the 11 eyes with KCS, six had improved subjective scores and fluorescein scores, and five had improved rose bengal scores after the use of serum drops. For the two patients who used serum eyedrops post-PK, there was a stable and intact epithelium at 1 week. Cessation of serum drops during the postoperative period led to deterioration in the subjective and objective scores in both patients. One developed a PED that responded to reinstitution of serum drops. The morphology and ATP levels of cultured epithelial cells exposed to serum were better maintained than those exposed to hypromellose. CONCLUSION: Autologous serum drops are useful for PED and KCS. This effect may be related to a number of active factors in serum including growth factors, fibronectin, vitamin A, and anti-proteases. In vitro toxicity testing demonstrated that serum drops have reduced toxicity compared with unpreserved hypromellose. Currently regulatory restrictions in the UK have prevented the establishment of a prospective randomised controlled trial examining the efficacy of autologous serum drops for the management of this group of ocular surface disorders.
Administration, Topical↗
Toxicity of natural tear substitutes in a fully defined culture model of human corneal epithelial cells.
PURPOSE: Serum and saliva have recently been advocated as natural tear substitutes for intractable aqueous-deficient dry eyes, but the effects of these fluids on corneal epithelium have not been well characterized. A laboratory study was performed in a defined test model to compare the toxicity of natural and pharmaceutical tear substitutes and to identify potentially toxic factors in natural tear substitutes, such as amylase, hypotonicity, and variations in preparation. METHODS: Primary human corneal epithelial cells were cultured with defined keratinocyte serum-free medium. The cells were incubated with hypromellose (hydroxypropylmethylcellulose 0.3%) with and without benzalkonium chloride 0.01%, saliva with differing osmolalities, 100% serum, and 50% serum (1:1 vol/vol with chloramphenicol 0.5%) for varying times and concentrations. Toxicity was examined in four ways. Microvillous density was assessed with scanning electron microscopy. Cell membrane permeability and intracellular esterase activity were analyzed after staining with fluorescent calcein-AM/ethidium homodimer and cellular adenosine triphosphate (ATP) was quantified using a luciferin-luciferase-based assay. RESULTS: The toxicity ranking of the tear substitutes correlated in all assays. The ATP assay was the most sensitive, followed by ethidium cell permeability, and finally the esterase activity. Preserved hypromellose was more toxic than the unpreserved preparation. Among natural tear substitutes, natural saliva was most toxic. Isotonic saliva and 50% serum were of similar toxicity, and 100% serum was least toxic. Natural tear substitutes were-except for natural saliva-less toxic than unpreserved hypromellose. Hypotonicity, but not amylase, was the major toxic effect associated with saliva. The dilution of serum with chloramphenicol induced toxicity. CONCLUSIONS: This is the first toxicity study using human primary corneal epithelial cells cultured under fully defined conditions as an in vitro model. Cellular ATP is a sensitive parameter for quantifying toxicity. Isotonic saliva and serum offer greater therapeutic potential for severely aqueous-deficient dry eyes than do pharmaceutical tear substitutes.
Adenosine Triphosphate↗
Management and outcome of cataract surgery in ocular cicatricial pemphigoid.
BACKGROUND: Patients with ocular cicatricial pemphigoid (OCP) lose vision due to corneal disease or cataract, which may be senile, drug induced or complex. The success of cataract surgery in these patients may be limited by an increased risk of surgical complications due to difficult access and visualisation, exacerbation of the cicatrising disease following surgery or later progression of the corneal disease. We report our experience on cataract surgery in OCP. METHODS: Cataract surgery was performed on 15 eyes of 13 patients. In the pre- and postoperative examinations the stage of the condition (according Foster's classification), the degree of conjunctival hyperaemia and the visual acuity (VA) were evaluated and topical and systemic medication recorded. All procedures used a corneal incision. The technique was intracapsular (ICCE) in 1, extracapsular (ECCE) in 4 and phacoemulsification in 10 eyes. In 13 of 15 cases an intraocular lens was implanted. The unoperated fellow eyes constituted a control group. Duration of postoperative follow-up was 35.8+/-39.1 months. RESULTS: 10 of 15 eyes had stage III disease or worse before surgery. Two eyes following ECCE showed early postoperative progression of the disease. Postoperative visual acuity improved in 14 eyes by 2 or more lines. Preoperatively 5 eyes met the criteria for blind registration, whereas postoperatively all eyes achieved a VA of at least 0.1. In 6 eyes the VA was sufficient to allow driving. However, by the 22nd postoperative month progressive cicatricial and ocular surface disease resulted in a regression of the achieved visual rehabilitation in 8 eyes. CONCLUSION: OCP does not prevent successful cataract surgery if appropriate techniques are used and precautions taken. Systemic perioperative immunosuppression is necessary in patients with active conjunctival inflammation. The use of small clear corneal incision surgery is recommended to reduce the risk of an acute exacerbation of conjunctival inflammation. Although visual rehabilitation may be only temporary due to progression of the conjunctival or corneal disease in OCP, cataract surgery can provide some benefit, in severely disabled patients, without precipitating an acute exacerbation of OCP.
Aged↗
Quality of salivary tears following autologous submandibular gland transplantation for severe dry eye.
BACKGROUND: This study aimed to characterise the composition of the pre-ocular fluid after transplantation of the autologous submandibular gland (SMG) for patients with severe dry eye. METHODS: Stimulated and unstimulated pre-ocular fluid from 15 patients (17 eyes) with a viable SMG graft ("SMG-salivary tears"), as well as normal tears and SMG saliva (20 normal subjects/ 20 eyes), was sampled. As global tear parameters, fern pattern analysis and SDS gel electrophoresis were performed. As specific quality parameters, total protein content, secretory immunoglobulin A (SIgA), lysozyme, amylase, sodium, potassium and osmolality were measured using routine laboratory methods. The flow rate of SMG-salivary tears was determined in 5 patients by means of sequential scintillography. RESULTS: The fern pattern of SMG-salivary tears was coarse and thus more similar to normal SMG saliva than tears. SDS gel electrophoresis of the SMG-salivary tears showed albumin and two unidentified proteins in addition to the normal tear pattern. Osmolality and total protein content of SMG-salivary tears were higher than in normal SMG saliva, but still lower than in normal tears. High activities of normal tear antibacterial proteins (SIgA, lysozyme and amylase) were detected in the salivary tears. Stimulation of the secretion did not alter the composition of SMG-salivary tears. The flow rate of SMG-salivary tears was closer to that of normal tears than normal SMG saliva. CONCLUSION: Salivary tears resulting from SMG-transplantation represent condensed SMG saliva. Thus their quality is intermediate between normal tears and normal SMG saliva. High levels of secretory proteins demonstrate that the gland maintains an active function. Surgical denervation and residual tear components from the ocular surface are the most likely factors to cause the complex differences between normal SMG saliva and SMG-salivary tears. The effects of this secretion on the ocular surface are currently being evaluated in a clinical and laboratory study.
Adolescent↗
Microvascular submandibular gland transfer for severe cases of keratoconjunctivitis sicca.
Free submandibular salivary gland transfer was investigated as a surgical method for the treatment of severe keratoconjunctivitis sicca. In an animal model, we examined the tolerance of warm ischemia of the submandibular gland. After temporary interruption of the blood supply (1 to 6 hours), the morphologic changes in the submandibular gland were analyzed histologically and immunohistochemically in 41 rabbits. From 1.5 hours ischemia onward, an increasing structural damage of the parenchyma with emphasis on the secretory cells was seen. Six hours of ischemia caused total necrosis of the salivary gland. Our clinical experience includes 24 highly selected patients suffering from keratoconjunctivitis sicca, in whom we transferred 31 autologous submandibular glands to the temple for permanent autologous tear substitution within the past 4 years. The glands were implanted into a pocket prepared in the temporalis muscle, and the nourishing vessels were anastomosed to the superficial temporal artery and vein. The submandibular duct was implanted into the upper lateral conjunctival fornix. The transferred glands were left denervated. In addition to the clinical examination, scintigraphy with Tc 99m pertechnetate was used to document the graft's viability after the transfer. Viable incorporation with longstanding secretory function occurred in 26 of the 30 transplanted denervated salivary glands. The resulting lubrication of the treated eyes was irregular for up to 3 months in almost even case. One year after surgery, all patients with a viable transplant developed at least occasional epiphora, which was surgically managed by reducing the size of the graft in 10 patients. No severe side effects were seen in this series. The ophthalmologic evaluation of the method included the assessment of dry eye symptoms and of the volume and quality of ocular lubrication (Schirmer test, fluorescein break-up time), the pathology of the ocular surface (rose bengal staining), and the need for pharmaceutical tear substitutes. One year after surgery, 18 of 27 cases assessed were judged as significantly improved by these tests.
Adolescent↗
Matrix metalloproteinases in sterile corneal melts.
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Aged↗
[Anisocoria after unilateral photorefractive keratectomy. Result of a lesion of the pupillary sphincter muscle?].
BACKGROUND: After unilateral photorefractive keratectomy (PRK) for myopia correction, relative mydriasis of the treated eye was noticed. The aim of this study was to determine the incidence and possible etiology of this anisocoria. PATIENTS AND METHODS: In a prospective clinical study we examined eight consecutive patients after PRK of a spherical equivalent of -1.0 to -8.5 D with a 6.5-7.0 mm optical zone (Schwind-Keratom) for up to 10 months. Measurements of the pharmacological uninfluenced pupillary diameter were carried out with a Goldmann perimeter under 31.5 asb and under four different room light and distance conditions. In five patients a hard contact lens of 0 D power was fitted to the treated eye, so that the laser-induced central corneal flattening was compensated for by the sublenticular tear film, and the pupillary diameter was measured again. The influence of pilocarpine 0.1% eye drops to the pupil was also examined. RESULTS: Postoperatively, the pupil of the PRK-treated eye measured up to 1.75 mm larger than that of the fellow eye in all patients. The amount of anisocoria showed a small negative correlation with the interval between the PRK procedure and the day of measurement. It did not correlate significantly with the amount of induced refractive change, applied energy, application of pilocarpine 0.1% eye drops or the contact lens fitting. CONCLUSION: After unilateral PRK, anisocoria can regularly be observed. At present its definite pathogenesis is unclear, although certain possible optical and neuronal mechanisms have been excluded. The most probable etiology is a mild lesion of the pupillary sphincter muscle because of its localization in the center of the laser shock wave distribution.
Adolescent↗
[Diode laser thermokeratoplasty. Initial clinical experiences].
PURPOSE: Pulsed holmium lasers are currently used to correct hyperopia by means of laser thermokeratoplasty (LTK). Series of microsecond laser pulses are applied with a high repetition rate to induce shrinkage of corneal collagen fibers. The pulsed energy application results in intrastromal temperature peaks of up to 200 degrees C. A continuously emitting laser diode can--as we demonstrated recently in an invivo study on minipigs--be used for LTK and may be of advantage because the temperature rise is more steady. The aim of this study was to examine the safety, amount, and stability of hyperopic correction of diode LTK on blind human eyes. METHODS: We used a laserdiode that was set to continuously emit light at lambda = 1.854 microns/mu a = 1.04 mm-1 (group I, n = 4) or 1.87 microns/mu a = 1.92 mm-1 (group II, n = 4). Radiation energy was 100 to 150 mW for 10 s per coagulation. Eight coagulations on a single ring (group I) and 16 coagulations on a double ring (group II) diameter were applied in the cornea concentric to the entrance pupil by means of a vacuum-fixed application mask (group I = conjunctival fixation; group II = corneal fixation) and a handpiece with a focusing optic. Preoperatively as well as 1 week, 1, 2, 3, 6 12 and 18 months postoperative ophthalmologic controls were performed and the corneal refractive power was measured. RESULTS: In group I initial refractive changes of up to +4.9 D were achieved (1 week postoperative). However, due to the great penetration depth of the laser irradiation, large endothelial defects resulted beneath the stromal coagulations. In group II an initial refractive change of up to +6.8 D was achieved and as a result of the reduced penetration depth, the endothelial cell damage was much reduced. Partial regression of the refractive effect occurred in all subjects, which continued in higher refractive changes during the 2nd postoperative year. The refractive effect at 12 months was +0.6 to +1.5 D in group I and +0.9 to +5.7 D in group II. At 12 months the induced astigmatism was 0.5 to 2.2 D in group I and 0.3 to 1.6 D in group II. No serious adverse effects were noticed. CONCLUSION: A continously emitting laser diode working at a wavelength of 1.87 microns can be used to correct hyperopia by means of LTK safely and effectively. Regression occurs predominantly in the first 6 postoperative months. Further studies must be conducted to determine the importance of patient inherent parameters such as age in establishing a nomogram.
Adult↗
[Thermal damage to the corneal endothelium in diode laser thermokeratoplasty].
Laser thermokeratoplasty (LTK) can be applied for correction of hyperopia and astigmatism by means of concentrically placed coagulations. Because of the temperature rise during coagulation, damage of the endothelial cells directly below the irradiated areas is possible. In this study, we examined the extent of the thermally denatured zones for different laser parameters and the threshold of thermal endothelial damage as a function of of temperature and duration of elevated temperatures. The threshold for thermal damage of endothelial cells was determined in isotonic NaCl solution for temperature exposures of 10 s and 1 min in a water bath. To determine the damage zones, corneas were irradiated under standardized conditions with a continuously emitting infrared (cw-IR) laser diode at various wave-lengths and different power values and were stained after preparation with trypan blue and alizarine red. The extensions of the damage zones were compared with calculated isotherms. Fifty percent cell damage was found at temperatures of 65 degrees C for heating times of 10 s and at 59 degrees C for 1 min. With thicker corneas, less laser power and higher absorption coefficients, the damage zone was reduced. The damage range determined corresponded to the calculated isotherms of 60 degrees C and 70 degrees C. Regarding clinical LTK, a loss of endothelial cells can be predicted and minimized or totally avoided by choosing the appropriate irradiation parameters.
Animals↗
Quality of salivary tears following autologous submandibular gland transplantation for severe dry eye.
BACKGROUND: This study aimed to characterise the composition of the pre-ocular fluid after transplantation of the autologous submandibular gland (SMG) for patients with severe dry eye. METHODS: Stimulated and unstimulated pre-ocular fluid from 15 patients (17 eyes) with a viable SMG graft ("SMG-salivary tears"), as well as normal tears and SMG saliva (20 normal subjects/20 eyes), was sampled. As global tear parameters, fern pattern analysis and SDS gel electrophoresis were performed. As specific quality parameters, total protein content, secretory immunoglobulin A (SIgA), lysozyme, amylase, sodium, potassium and osmolality were measured using routine laboratory methods. The flow rate of SMG-salivary tears was determined in 5 patients by means of sequential scintillography. RESULTS: The fern pattern of SMG-salivary tears was coarse and thus more similar to normal SMG saliva than tears. SDS gel electrophoresis of the SMG-salivary tears showed albumin and two unidentified proteins in addition to the normal tear pattern. Osmolality and total protein content of SMG-salivary tears were higher than in normal SMG saliva, but still lower than in normal tears. High activities of normal tear antibacterial proteins (SIgA, lysozyme and amylase) were detected in the salivary tears. Stimulation of the secretion did not alter the composition of SMG-salivary tears. The flow rate of SMG-salivary tears was closer to that of normal tears than normal SMG saliva. CONCLUSION: Salivary tears resulting from SMG-transplantation represent condensed SMG saliva. Thus their quality is intermediate between normal tears and normal SMG saliva. High levels of secretory proteins demonstrate that the gland maintains an active function. Surgical denervation and residual tear components from the ocular surface are the most likely factors to cause the complex differences between normal SMG saliva and SMG-salivary tears. The effects of this secretion on the ocular surface are currently being evaluated in a clinical and laboratory study.
Adolescent↗
Continuous-wave diode laser thermokeratoplasty: first clinical experience in blind human eyes.
PURPOSE: To evaluate the safety and stability of laser thermokeratoplasty (LTK) with a continuous-wave diode laser in blind human eyes and to optimize parameters for a study in sighted eyes. SETTING: Department of Ophthalmology, Medical University Lübeck, Germany. METHODS: A continuous-wave diode laser was set to emit radiation with a wavelength of 1.854 microns (Group 1, n = 4) or 1.870 microns (Group 2, n = 4) and 100 to 150 mW power for 10 seconds. A focusing handpiece was coupled with an application mask and fixed by partial vacuum to the conjunctiva or cornea. The radiation was focused into the corneal stroma between 400 and 600 microns in Group 1 and set to 1000 microns in Group 2. Eight (Group 1, single ring) or 16 (Group 2, double ring) coagulations were applied. RESULTS: The refractive change increased with higher laser power and smaller ring diameters. Two rings of coagulations provided higher and more stable refractive changes of up to 5.66 diopters (D) than a single ring. The refractive effect stabilized between 3 and 6 months postoperatively. At 1 year, mean refractive change was +0.99 D +/- 0.39 (SD) in Group 1 and +2.32 +/- 2.24 D in Group 2. Extensive endothelial damage occurred in Group 1 but was minimal in Group 2. CONCLUSIONS: Diode LTK was used to treat hyperopia safely and effectively. Regression occurred mainly in the first 3 postoperative months. With a wavelength of 1.870 microns, corneal endothelial damage was limited.
Adult↗
[Transplantation of autologous submandibular glands in very severe keratoconjunctivitis sicca. 2 year outcome].
INTRODUCTION: The conservative treatment of the most severe cases of keratoconjunctivitis sicca (KCS) can be sometimes frustrating. Especially with an underlying autoimmunologic disorder, even the application of artificial tears as often as every 5 min may not prevent further damage to the ocular surface. A microvascular transplantation of the autologous submandibular gland (SG) can be performed by a maxillo-facial surgeon as an alternative approach for those cases. We report 2 years of ophthalmological experience with the results of this procedure. MATERIAL AND METHODS: To date 27 operations have been performed in 23 patients. The SG was moved from its natural site into the temporal fossa. The secretory duct was implanted into the conjunctival fornix and the gland's vessels connected to the temporal artery and vein. A complete ophthalmological examination has been performed in 25 eyes of 21 patients up to 1 year and in 11 eyes of 9 patients 2 years after surgery. RESULTS: Three months and 1 year postoperatively 19 of 25, and 2 years postoperatively 8 of 11 transplants remained vital. The baseline secretion increased in patients with a vital transplant from an average of 1.6 +/- 1.3 mm before the operation to 16.2 +/- 11.3 mm after 3 months and 20.6 +/- 10.6 mm after 1 year. Ten of 19 vital grafts were reduced 1 year after transplantation in a minor second procedure to control an increasing epiphora. Subsequently baseline secretion was reduced to 13.6 +/- 8.2 mm 2 years after transplantation. Patients with a vital graft reported in 84% of cases (16 of 19) at 3 months, and 79% at 1 year (15 of 19) and 2 years (7 of 8), a strong relief of dry eye symptoms. In 58% (3 months), 79% (1 year) and 63% (2 years) of the eyes with a vital transplant all artificial tear substitution could be stopped. Break-up time increased significantly, resulting in reduced bengal rose staining. CONCLUSION: The transfer of the autologous SG into the temporal fossa can be used to provide patients with very severe KCS with a continuous, endogenous source of ocular lubrication. Despite surgical denervation the graft maintains a sufficient baseline secretion over a period of years. Subjective symptoms and the application of pharmaceutical lubricating substances are reduced to a large extent. If epiphora occurs, it can be controlled by surgically reducing the transplant. The influence of SG saliva on the ocular surface is the object of ongoing studies.
Adult↗
Transplantation of the autologous submandibular gland for most severe cases of keratoconjunctivitis sicca.
OBJECTIVE: This study aimed to examine the long-term qualitative and quantitative function of the secretion of transplanted autologous submandibular glands in patients with most severe keratoconjunctivitis sicca. DESIGN: The study design was clinical. PARTICIPANTS: The authors performed 26 operation in 22 patients. A complete ophthalmologic examination was performed in 16 eyes of 13 patients 1 week and 3 months and in 8 eyes of 8 patients 1 year after surgery. INTERVENTION: The submandibular gland was moved from its natural site into the temporal fossa. The glands supplying vessels were connected to the temporal artery and vein, and its secretory duct was implanted into the conjunctival fornix. MAIN OUTCOME MEASURES: Scintigraphy with Tc 99m Pertechnetate was used to document the graft vitality. Subjective symptoms and application frequency of artificial tears were recorded. Baseline as well as stimulated secretion and breakup time were measured and rose bengal staining and ocular ferning test were performed. In selected cases, the secretory product could be sampled for the detection of electrolytes, amylase, and secretory immunoglobulin A (SIgA). RESULTS: Scintigraphy showed vital gland tissue in 14 of 16 grafts at 3 months and 6 of 8 grafts at 1 year after surgery. Two of the 16 transplants were lost completely during the first 3 postoperative months, 1 because of an underlying autoimmunopolyendokrinopathy and the other because of an insufficient vascular anastomoses. In eyes with a vital transplant, baseline secretion and breakup time were increased significantly at 3 months and 1 year after surgery. Patients with a vital transplant reported a strong relief of symptoms and were able to stop taking artificial tear substitution at 1 year. Electrolytes showed a fluctuating concentration. A year after transplantation, the SIgA and amylase concentrations were more than ten times increased compared to normal tear values. CONCLUSION: Microvascular transferral of an autologous, paralytic submandibular gland results in a significant relief of subjective symptoms, a reduction of artificial tear applications, and an increase of baseline secretion over the first postoperative year. The composition and volume of the secretory product fluctuate, but high values of SIgA and amylase show an actively secreting graft. Although the authors' long-term experience still is limited, they believe that the procedure is a promising alternative approach for desperate dry eye conditions.
Amylases↗
Diode laser thermokeratoplasty: application strategy and dosimetry.
PURPOSE: To investigate suitable application parameters for efficient hyperopic correction by laser thermokeratoplasty (LTK) using mid-infrared laser diodes. SETTING: Medical Laser Center Lübeck, Lübeck, Germany. METHOD: A tunable continuous-wave laser diode in the spectral range between 1.845 and 1.871 microns was used. Transmitted by waveguides, the laser energy was used to induce coagulations on freshly enucleated porcine eyes to increase corneal curvature. The coagulations were equidistantly applied by a fiber-cornea contact and a noncontact focusing device that were adjusted on a ring concentric to the corneal apex. Different laser parameters and application geometries were evaluated. Refractive changes were measured by computer-assisted corneal topography before and after treatment. Polarization light microscopy and temperature calculations were used to analyze the coagulations. RESULTS: Because of the tunability of the laser diode, the influence of the corneal absorption coefficient (between 0.9 and 1.6 mm-1) on the refractive change could be measured. A laser power between 125 and 200 mW was adequate to achieve refractive changes up to 10.0 diopters. In the preferable focusing device, the refractive change increased almost logarithmically with the irradiation time up to 15 seconds. The number of coagulations on a fixed application ring showed no significant influence on refractive change; however, it showed an almost linear decrease with increasing ring diameter from 5.0 to 10.0 mm. Histological analysis revealed 3 stages of thermal damage. CONCLUSION: Diode LTK provided defined and uniform coagulations when using a well-adapted focusing device, resulting in sufficient refractive change. The results indicate that diode LTK is superior to pulsed holmium LTK.
Absorption↗
[Consequent use of the Aachen therapy concept after severe chemical burns of both eyes].
BACKGROUND: Severe chemical burn and its complications still are a serious threat to the afflicted eye, particularly in case of insufficient treatment. Rehabilitation of visual acuity can be achieved only in the minority of cases. PATIENT: We present a 49-year-old female patient, who suffered a severe chemical burn in both eyes by alcaline detergent. Visual acuity was OD 20/50, OS light perception. After directly started acute treatment as well as peritomy, peridectomy, tenon plasty and application of a PMMA contact lens a stabilization was achieved. Complete rehabilitation of visual acuity was gained by EDTA abrasion, excimer treatment, penetrating keratoplasty and cataract surgery. Last examination showed a visual acuity of 25/20 in both eyes. CONCLUSIONS: Even in severe chemical burn an optimal result can be achieved by using an adequate treatment conception. Immediate beginning of therapy is important as well as persistent and persevering application of the treatment. Repeated, if necessary daily, excisions of necrotic tissue associated with tenon plasty and application of a PMMA contact lens have special importance.
Burns, Chemical↗