Long-term changes in corneal endothelial morphology after discontinuation of low gas-permeable contact lens wear.

PURPOSE: Low gas-permeable contact lens wear of polymethyl methacrylate or hydroxyethyl methacrylate material is known to cause morphologic abnormalities in the corneal endothelial cell layer. These lenses were widely prescribed and successfully worn until their use was actively discouraged in the late 1980s and early 1990s. This study was designed to investigate whether discontinuation of low gas-permeable contact lens wear leads to an improvement of corneal endothelial cell morphology. METHODS: At the time of discontinuation and at least 5 years after discontinuation of low gas-permeable contact lens wear, noncontact specular photographs of the central corneal endothelium were made in 66 patients (14 male and 52 female, mean age 37.7 +/- 8.4, range 24.6-69.0). By computer analysis of endothelial photographs, parameters for polymegethism and pleomorphism were calculated, as well as cell density. RESULTS: Mean follow-up time between photographs was 6.8 years (SD 1.1). Sixty-one patients were refitted with rigid high gas-permeable contact lenses or high-water-content soft lenses, and 5 patients switched to spectacle wear. A small but significant recovery of the corneal endothelial cell morphology was found for the mean coefficient of variation of cell area, from 37.5 to 35.7 (P = 0.022), and for the coefficient of variation of the number of sides, from 13.1 to 12.4 (P = 0.004). The mean percentage of hexagonal cells increased from 54.2 to 56.2 (P = 0.013). Although the corneal endothelial cell morphology improved significantly on cessation of LGP contact lens wear, the values did not return to levels observed in normal, non-contact lens wearing individuals. During follow-up, the mean endothelial cell density decreased significantly (P = 0.001) from 2994 to 2890 (a 3.5% cell loss in 6.8 years), which is similar to the known normal age-related cell loss of 0.6% per year in non-contact lens wearing healthy individuals. CONCLUSION: Endothelial polymegethism and pleomorphism caused by PMMA or HEMA contact lens wear is partly reversible.

Endothelial cell density after posterior lamellar keratoplasty (Melles techniques): 3 years follow-up.

PURPOSE: To report the midterm endothelial cell density measurements after posterior lamellar keratoplasty (Melles techniques). DESIGN: Cohort study. METHODS: Fifteen consecutive eyes of 15 patients in whom a posterior lamellar keratoplasty procedure was performed for pseudophakic bullous keratopathy or Fuchs' endothelial dystrophy were evaluated. In 11 corneas the donor tissue was inserted through a 9.0-mm sclerocorneal pocket incision (technique A); in four cases the donor was folded and inserted through a 5.0-mm incision (technique B). Specular microscopy was performed at 6, 12, 24, and 36 months after surgery, to measure the endothelial cell density. RESULTS: Mean postoperative endothelial cell density averaged 2,126 cells/mm(2) (+/-548) at 6 months, 1,859 cells/mm(2) (+/-477) at 12 months, 1,385 cells/mm(2) (+/-451) at 24 months, and 1,047 cells/mm(2) (+/-425) at 36 months. CONCLUSION: In posterior lamellar keratoplasty, the donor corneal endothelium showed a decrease in cell density similar to that after conventional full-thickness penetrating keratoplasty.

Unintentional inversion of corneal buttons during penetrating keratoplasty: clinico-pathological report of two cases.

AIM: This report describes the clinico-pathological features of unintentionally inverted corneal buttons in two patients. METHODS: A clinico-pathological report. RESULTS: Two patients who underwent repeat keratoplasty for failed grafts were found to have inverted corneal buttons on histopathological examination. A detailed description of the pathological features of the inverse keratoplasty and the clinical outcome after repeat keratoplasty is presented. CONCLUSION: Inadvertent inverse keratoplasty should be considered as a rare cause of corneal graft failure. The serious complication of anterior chamber epithelialization seems to be unlikely and the prognosis following repeat penetrating keratoplasty appears to be very good.

[Refractive surgery: most commonly used techniques, results and complications]. / Refractiechirurgie: meest gebruikte technieken, resultaten en complicaties.

Refractive surgery is gaining enormous popularity. It is estimated that in 2001, refractive surgery was performed on 1 in 8000 persons in the Netherlands. Photorefractive keratectomy and laser in-situ keratomileusis are effective and predictable for the correction of myopia up to 10.0 D and hypermetropia up to +4.5 D. There is rarely any significant loss of best-corrected visual acuity postoperatively. For the correction of higher levels of myopia and hypermetropia, phakic intraocular lenses can be implanted in the anterior or posterior eye chamber, in other words in front of the natural lens. The magnification effect of these lenses often results in improved vision at higher levels of myopia. Good preoperative selection of refractive surgery candidates is essential and patients should be properly informed about the results, potential complications and adverse effects of refractive surgery techniques.

Suture-related complications following keratoplasty: a 5-year retrospective study.

PURPOSE: To study the incidence of suture-related complications following penetrating keratoplasty (PK) and their effect on the success of corneal grafting. METHODS: The records of 332 patients receiving 361 grafts in 1993 and 1994 were reviewed, and suture-related complications were recorded. These complications were divided into five groups: suture erosions, infiltrates at the suture sites, infectious keratitis, loose sutures with imminent wound dehiscence, and wound dehiscence after suture removal. RESULTS: Occurrence rates were suture erosions, 10.8%; infiltrates, 9.4%; infectious keratitis related to sutures, 3.3%; loose sutures with imminent wound separation in need of surgical repair, 8.3%; and wound dehiscence following suture removal, 2.4%. CONCLUSIONS: Suture-related complications frequently occur after PK. Infectious keratitis and wound separations needing surgical repair may lead to loss of best-corrected visual acuity due to scarring, induced allograft reactions, and/or increased astigmatism. Recommendations for post-PK suture management are proposed.

Intravitreal vancomycin and gentamicin concentrations in patients with postoperative endophthalmitis.

BACKGROUND/AIMS: To study the intravitreal antibiotic concentrations and the efficacy of an intravitreal dosing regimen to treat patients with postoperative bacterial endophthalmitis. This regimen, based on pharmacokinetic/pharmacodynamic considerations, relies on a repeat antibiotic injection of a lower dose than is generally used. METHODS: In consecutive patients with suspected postoperative endophthalmitis a vitreous biopsy for bacterial culture was taken before 0.2 mg vancomycin and 0.05 mg gentamicin were injected intravitreally. After 3 or 4 days a second biopsy was taken for bacteriological culture and to measure intravitreal vancomycin and gentamicin concentrations, followed by a repeat injection of 0.2 mg vancomycin. RESULTS: 17 patients entered the study. In 11 patients the initial bacterial culture was positive, predominantly coagulase negative staphylococci. All second vitreous biopsies were sterile. Intravitreal vancomycin levels varied between 2.6 and 18.0 microg/ml (mean 10.3 (SD 4.1) microg/ml) after 3 days and between 3.1 and 16.6 microg/ml (mean 7.5 (6.2) microg/ml) after 4 days which is well above the minimal inhibitory concentration for most micro-organisms. Concentrations of intravitreal gentamicin varied between 0.90 and 3.3 microg/ml (mean 1.6 (0.72) microg/ml) after 3 days and between 1.2 and 2.6 microg/ml (mean 1.9 (0.99) microg/ml) after 4 days. CONCLUSION: This dosing regimen resulted both in adequate intravitreal vancomycin and gentamicin levels for over a week as well as in negative second cultures. This study also provides new information on intravitreal vancomycin and gentamicin concentration over time in patients with postoperative endophthalmitis.

Contact lens fitting in a patient with keratectasia after laser in situ keratomileusis.

We present a case of unilateral iatrogenic keratectasia developing 15 months after bilateral laser in situ keratomileusis using a broad-beam excimer laser (Bausch & Lomb Keracor 116) to treat -3.5 -1.5 x 85 diopters of myopia. Preoperative pachymetry in the eye measured 450 microm without topographical changes suggesting keratoconus or forme fruste keratoconus. Contact lens fitting to provide 20/25 visual acuity is described.

Rigid gas-permeable contact lens fitting in LASIK patients for the correction of multifocal corneas.

BACKGROUND: Laser in situ keratomileusis (LASIK) has recently become the most commonly performed refractive surgery procedure. Results are promising in correcting low to moderate myopia. Most complications occur during the surgeon's learning curve. One of the complications is a decentration of the ablated area that causes monocular diplopia and a nocturnal halo phenomenon due to a multifocality of the corneal surface overlying the entrance pupil. The corneal shape is significantly altered after LASIK. We evaluate the efficacy of rigid gas-permeable contact lens designs and fitting techniques used in eight eyes with multifocal LASIK ablations to correct haloes and impaired night vision complaints. METHODS: We used large-diameter tetra-curved rigid gas-permeable (RGP) contact lenses for visual recovery in eight eyes of seven LASIK patients. We used the power on the transition zone of the corneal topographic map, 0.2 mm outside the ablated refractive area, for selection of the back optic zone radius of the RGP contact lenses. Procedures for lens fitting are described. Visual acuity (high-contrast logarithm of the minimum angle of resolution, LogMAR) was measured before- and 6 months after contact lens fitting. RESULTS: Large-diameter tetra-curve RGP lenses with a mean diameter of 11.85 (SD 0.16) mm were successfully used in LASIK patients with multifocal corneas. Mean best spectacle-corrected visual acuity was +0.3 LogMAR (SD 0.19; in Snellen equivalent, 20/40) and improved significantly with the contact lenses to +0.08 LogMAR (SD 0.11; in Snellen equivalent, 20/25, P=<0.01). During the follow-up period of 16.7 months, the average daily wearing time of the lenses was 12.5 h. Contact lenses with a standard geometry were not useful due to excessive movement and inadequate centration. CONCLUSIONS: Contact lenses with large diameters, in combination with selection of the back optic zone radius 0.2 mm peripheral of the refractive ablation zone, facilitate contact lens fitting to restore best-corrected visual acuity in LASIK patients with multifocal corneas.

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.

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.

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.

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.

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.

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).

[Staining the lens capsule with trypan blue for visualizing capsulorhexis in surgery of mature cataracts]. / Färbung der Linsenkapsel mit Trypanblau zur Visualisierung der Kapsulorhexis bei Maturkataraktchirurgie.

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.

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.

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.

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.