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Biomedical subjects

W H Beekhuis

Publications and source records attributed to W H Beekhuis.

At least 19 recordsLinked to original sources
PubMed2000

Preliminary clinical results of posterior lamellar keratoplasty through a sclerocorneal pocket incision.

PURPOSE: To report the preliminary results of a surgical technique for transplantation of posterior corneal tissue through a sclerocorneal pocket incision for corneal endothelial disorders. DESIGN: Retrospective, noncomparative, interventional cases series. PARTICIPANTS AND INTERVENTION: In seven sighted human eyes, a deep stromal pocket was created across the cornea through a 9.0-mm superior scleral incision. A 7.0- or 7.5-mm diameter, posterior lamellar disc was excised and replaced by a 'same size' donor posterior disc, without suture fixation. The scleral incision was sutured. MAIN OUTCOME MEASURES: Intra- and postoperative complications, best spectacle-corrected visual acuity, keratometry, topography, biomicroscopy, pachymetry, and endothelial cell density were evaluated. RESULTS: Six to 12 months after surgery, all transplants were clear and in position. Best spectacle-corrected visual acuity was limited by preexisting maculopathies in two eyes and varied from 20/80 to 20/20. Postoperative astigmatism averaged 1. 54 diopters (D; standard deviation [SD] +/- 0.81 D), pachymetry averaged 0.49 mm (SD +/- 0.09 mm), and postoperative endothelial cell density averaged 2520 cells/mm(2) (SD +/- 340 cells/mm(2)). In one eye, a microperforation occurred during stromal pocket dissection so that the procedure was converted into a penetrating keratoplasty. CONCLUSIONS: Posterior lamellar keratoplasty through a sclerocorneal pocket incision is a feasible surgical approach to manage corneal endothelial disorders.

Aged↗
PubMed2000

A quick surgical technique for deep, anterior lamellar keratoplasty using visco-dissection.

PURPOSE: To describe a new surgical technique for deep, anterior lamellar keratoplasty using a viscoelastic for dissection of Descemet's membrane (DM) from the posterior stroma. METHODS: Through a paracentesis, aqueous was exchanged by air to visualize the posterior corneal surface-i.e., the air-to-endothelium interface. Using the interface as a reference plane, a 30 gauge needle was inserted into the cornea to just anterior to DM. Viscoelastic was injected to separate DM from the posterior stroma, and a recipient, anterior lamella was excised. A full-thickness donor button was sutured into the recipient bed, after stripping its DM. RESULTS: In 25 eye bank eyes, the procedure could be completed in 20 eyes; in 5 eyes, DM ruptured during visco-dissection. With light microscopy, dissection depth was located at the level of DM. In two patient eyes the procedure could be completed. In a third patient eye DM ruptured during visco-dissection, and the procedure was converted into a penetrating keratoplasty. CONCLUSION: Using visco-dissection, a lamellar keratoplasty can be performed quickly, with the donor-to-recipient interface just above the recipient DM, i.e., with a nearly perfect anatomical replacement of all corneal stroma. There is substantial risk of rupture or microperforation of DM during surgery.

Adult↗
PubMed1999

Incidence of contact-lens-associated microbial keratitis and its related morbidity.

BACKGROUND: The incidence of contact-lens-associated microbial keratitis is uncertain and its related morbidity in the general population of contact-lens wearers is not known. We examined these issues in a prospective epidemiological study. METHODS: We surveyed all practising ophthalmologists in the Netherlands to identify all new cases of microbial keratitis reported during a 3-month period in 1996. Follow-up telephone calls were made to examine ocular morbidity. We undertook annual nationwide telephone surveys between 1994 and 1997 to estimate the prevalence of contact-lens wear. FINDINGS: Of 440 ophthalmologists contacted, 379 provided information. There were 92 cases of microbial keratitis; 17 used daily-wear rigid gas-permeable lenses, 63 daily-wear soft lenses, and 12 extended-wear soft lenses. The estimated annualised incidence of microbial keratitis was 1.1 per 10,000 (95% CI 0.6-1.7) users of daily-wear rigid gas-permeable lenses, 3.5 per 10,000 (2.7-4.5) users of daily-wear soft lenses, and 20.0 per 10,000 (10.3-35.0) users of extended-wear soft lenses (p<0.00001 for comparison between all groups), Five of the 92 patients achieved a final visual acuity of 20/70 or less. Pseudomonas and Serratia spp were the organisms most commonly isolated. Pseudomonas keratitis accounted for the largest mean diameter of corneal ulcers, the highest mean number of days in hospital, the greatest number of mean outpatients visits, and the poorest visual acuity outcome. INTERPRETATION: The incidence of microbial keratitis among users of extended-wear soft contact lenses in the Netherlands is similar to that reported in the USA during 1989. Awareness of risk factors and improvement in contact-lens materials have not led to a decrease in incidence. Overnight wear should be strongly discouraged.

Adolescent↗
PubMed1999

Posterior lamellar keratoplasty for a case of pseudophakic bullous keratopathy.

PURPOSE: To describe a new surgical technique for posterior corneal transplantation. METHODS: An elderly patient had painful, pseudophakic bullous keratopathy with low visual potential. Through a 9.0-mm scleral tunnel incision, a midstromal pocket was dissected across the cornea, and a posterior lamellar disk 7.0-mm in diameter, which consisted of posterior stroma, Descemet membrane, and endothelium, was excised. A similarly shaped donor posterior disk was implanted in the recipient opening without suture fixation, and the scleral incision was sutured. RESULTS: Throughout the postoperative period, the posterior corneal transplant remained clear and in position. Three months after surgery, the "suture-in" astigmatic error was 3.5 diopters. Pachymetry measured 0.44 mm. CONCLUSION: Posterior lamellar keratoplasty may be a new surgical approach with which to manage corneal endothelial disorders.

Corneal Diseases↗
PubMed1999

[Staining the lens capsule with trypan blue for visualizing capsulorhexis in surgery of mature cataracts].

BACKGROUND: A capsulorhexis may be difficult to perform in the absence of a red fundus reflex. PATIENTS AND METHODS: After application of 0.3 mL trypan blue 0.1%, a quick and homogeneous staining of the anterior lens capsule was obtained in 100 patients with a mature cataract, to visualize the capsulorhexis during a phacoemulsification procedure. RESULTS: No adverse reactions related to the dye were observed up to 18 months after surgery. CONCLUSION: Trypan blue staining of the anterior lens capsule may therefore be a safe technique to facilitate the performance of a capsulorhexis in the absence of a red fundus reflex.

Capsulorhexis↗
PubMed1999

The future of lamellar keratoplasty.

New surgical techniques in lamellar keratoplasty, including phototherapeutic keratectomy, automated lamellar keratectomy, plano-epikeratoplasty, deep anterior lamellar keratoplasty, combined amniotic membrane and limbal transplantation, large-diameter corneoscleral lamellar keratoplasty, and posterior lamellar keratoplasty, have recently become available. These procedures broaden the array of treatments for corneal disorders and may be used as alternatives to penetrating keratoplasty.

Corneal Diseases↗
PubMed1999

A new surgical technique for deep stromal, anterior lamellar keratoplasty.

AIMS: To describe a new surgical technique for deep stromal anterior lamellar keratoplasty. METHODS: In eye bank eyes and sighted human eyes, aqueous was exchanged by air, to visualise the posterior corneal surface--that is, the "air to endothelium" interface. Through a 5.0 mm scleral incision, a deep stromal pocket was created across the cornea, using the air to endothelium interface as a reference plane for dissection depth. The pocket was filled with viscoelastic, and an anterior corneal lamella was excised. A full thickness donor button was sutured into the recipient bed after stripping its Descemet's membrane. RESULTS: In 25 consecutive human eye bank eyes, a 12% microperforation rate was found. Corneal dissection depth averaged 95.4% (SD 2.7%). Six patient eyes had uneventful surgeries; in a seventh eye, perforation of the lamellar bed occurred. All transplants cleared. Central pachymetry ranged from 0.62 to 0.73 mm. CONCLUSION: With this technique a deep stromal anterior lamellar keratoplasty can be performed with the donor to recipient interface just anterior to the posterior corneal surface. The technique has the advantage that the dissection can be completed in the event of inadvertent microperforation, or that the procedure can be aborted to perform a planned penetrating keratoplasty.

Adult↗
PubMed1999

A technique to visualize corneal incision and lamellar dissection depth during surgery.

PURPOSE: To describe a surgical technique to visualize the depth of corneal incisions and lamellar stromal dissections during surgery. METHODS: In porcine cadaver eyes, the aqueous was exchanged by air. Thus an air-to-endothelium interface (i.e., a useful optical surface) was created at the posterior corneal surface. The air-to-endothelium interface was used as a reference plane to visualize the corneal thickness and the relative depth of corneal incisions and dissections. Freehand peripheral corneal incisions, tangential keratotomy incisions, and lamellar stromal dissections were made at an intended corneal depth of 60, 80, and 99%. Light microscopy was used to measure the relative depth of the incisions and dissections. RESULTS: Achieved depth for peripheral corneal incisions averaged 65.2+/-5.3%, 78.8+/-5.1%, and 93.4+/-6.0%, respectively (p<0.05); and for tangential keratotomy incisions, 68.2+/-7.3%, 83.2+/-4.4%, and 95.8+/-3.6%, respectively (p<0.05). Achieved depth for lamellar stromal dissections averaged 58.3+/-9.4%, 81.1+/-3.4%, and 94.4+/-1.5%, respectively (p<0.05). Microperforations occurred with three incisions made at 99% intended depth. CONCLUSION: During surgery, the depth of incisions and lamellar dissections relative to the corneal thickness can be visualized by filling the anterior chamber with air (i.e., by creating an optical interface at the posterior corneal surface).

Air↗
PubMed1998

Depth predictability of stromal pockets in the posterior cornea.

PURPOSE: To evaluate the predictability of the depth of stromal pockets made in the posterior cornea for the excision of anterior or posterior lamellar corneal buttons with a planned thickness. METHODS: Stromal corneal pocket dissections were created in human eye bank eyes by making a peripheral arcuate keratotomy incision at 60, 80, or 95% of central pachymetry and creating a pocket from the bottom of the incision across the cornea. Pocket depth was measured by pachymetry immediately after surgery and by light microscopy. RESULTS: Mean achieved central pocket depth differed by 0.03+/-0.03 mm from the intended depth. Variation in depth across the pocket decreased from 0.07+/-0.02 mm for pockets made at 60% of the intended depth to 0.05+/-0.01 mm for pockets made at 80% depth, and 0.04+/-0.02 mm for pockets made at 95% depth (p < 0.01). Pachymetric and histological measurements of relative pocket depth averaged 64+/-9% and 73+/-7%, respectively, for pockets made at 60% of the intended depth, 82+/-7% and 86+/-3% for pockets made at 80% depth, and 91+/-7% and 92+/-3% for pockets made at 95% depth. The difference between pachymetric and histological relative pocket depth measurements decreased with deeper pocket depth (p < 0.01). CONCLUSIONS: In the posterior cornea, stromal pockets can be created to within 30 microm from the intended depth. Variation in depth throughout the pocket decreases with deeper pocket depth. Pachymetry is a reliable method to check the achieved pocket depth during surgery; the accuracy of pachymetry readings improves with deeper pocket depth.

Corneal Stroma↗
PubMed1998

A surgical technique for posterior lamellar keratoplasty.

PURPOSE: To design a surgical technique for transplantation of posterior corneal tissue, while leaving the recipient anterior cornea intact. METHODS: In human cadaver eyes, and in a cat and monkey model, recipient eyes had an 8.0-mm limbal incision made with a diamond blade set to 50% of central pachymetry. A stromal pocket was created across the cornea, and a 6.0-mm diameter posterior lamellar disc was excised. A donor posterior disc was implanted into the recipient opening, and the limbal incision was sutured. The procedure was evaluated with keratometry, biomicroscopy, endothelial (supra)vital staining, and light microscopy. RESULTS: In human cadaver eyes, post-operative astigmatism averaged 1.2 D (SD, +/- 0.6 D). Posterior transplants showed an intact endothelial cell layer with 1.0% (SD, +/- 1.2%) of cell death. In the animals, six (75%) eyes had clear transplants 2 weeks after surgery; one of these eyes later developed an allograft rejection. Two (25%) eyes showed corneal decompensation, because of inverted implantation of the donor disc. Microscopy showed minimal scarring at the donor-to-host interface and a normal wound-healing response at the posterior stromal wound edges. CONCLUSION: In experimental models, posterior lamellar keratoplasty can be performed through a limbal incision and a mid-stromal pocket. The procedure may be a potential alternative in the surgical management of corneal endothelial disorders.

Animals↗
PubMed1998

A new treatment for photophobia in posttraumatic aniridia: a case report.

PURPOSE: Using staining pigments with which we had gained experience in dermatography (medical tattooing) treatments of leucoma corneae, a new approach was developed to create an artificial iris-like staining at the mid-stromal level of the cornea to treat photophobia in a patient with posttraumatic aniridia. METHODS: After a central 4-mm half-depth trephination, a lamellar dissection of the corneal stroma toward the limbus was performed. A combination of colored pigments was introduced into this midstromal space, until a light blue artificial iris (to match the contralateral eye) with adequate blocking of light was created. RESULTS: A stable artificial iris was created in the mid-stromal level of the cornea. CONCLUSION: Dermatography pigments are stable in the corneal stroma and are useful to treat photophobia in aniridia following trauma.

Aniridia↗
PubMed1997

Newly acquired herpes simplex virus keratitis after penetrating keratoplasty.

BACKGROUND: After penetrating keratoplasty for reasons unrelated to herpes simplex virus (HSV) keratitis, any nonspecific epithelial defect may still be caused by HSV. The purpose of this study is to determine the incidence of newly acquired herpetic keratitis and to assess contributing factors. METHODS: The authors retrospectively studied the results of 2398 penetrating keratoplasties performed between 1980 and 1995. Three typical case histories are discussed. RESULTS: Of 2112 patients in whom the primary diagnosis was not related to HSV keratitis, 18 presented with epithelial herpetic keratitis in their corneal graft. The incidence of newly acquired herpetic keratitis after penetrating keratoplasty was 1.2 per 1000 person-years. In most cases, the infection occurred in the first 2 years after the transplantation. Most often, well-known reactivating stimuli could have caused the HSV infection. CONCLUSIONS: Herpes simplex virus keratitis may develop after penetrating keratoplasty even without a clinical history of HSV in the host. Thus, HSV should be considered in the differential diagnosis of a postpenetrating keratoplasty epithelial defect. The high incidence of this infection in the first 2 years after such surgery suggests a causal relation between corneal transplantation and the HSV infection.

Adult↗
PubMed1997

Corneal astigmatism after clear corneal and corneoscleral incisions for cataract surgery.

PURPOSE: To compare the astigmatism induced by clear corneal incisions (CCIs) and corneoscleral tunnel incisions (CSIs) for cataract surgery over 6 months. SETTING: Rotterdam Eye Hospital, rotterdam, The Netherlands. METHODS: Thirty-five patients having phacoemulsification were recruited prospectively; 15 had CCIs and 20, CSIs. Corneal topography was performed by computerized videokeratoscopy preoperatively and 6 months postoperatively. The change in keratometric astigmatism was calculated using the absolute magnitude and vector analysis methods. RESULTS: There was no significant difference between the change in astigmatism produced by the two incisions (Student's t-test). CONCLUSION: The CCI for cataract surgery did not produce significantly greater astigmatism than the CSI. Concern over CCIs having a greater risk of increasing corneal astigmatism is unfounded and does not justify withholding the technique from patients it could benefit.

Astigmatism↗
PubMed1997

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.

Administration, Topical↗
PubMed1997

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.

Adult↗
PubMed1997

Crohn's colitis and the cornea.

Ulcerative colitis (Crohn's disease) is a chronic relapsing inflammatory bowel disease of unknown etiology. The most common ocular complications include conjunctivitis and uveitis, particularly iritis. Herein, we describe a patient who had a decrease in visual acuity due to an increasing astigmatism. This was accompanied with a peripheral limbal thinning of the cornea and faint confluent corneal changes. No systemic activity was present during the period that the patient was monitored. Changes of astigmatism were followed up with videokeratography. This apparatus monitors changes in clinical course accurately and makes comparison possible between separate visits.

Adult↗