Quantification of blood-aqueous barrier breakdown after phacoemulsification in Fuchs' heterochromic uveitis.

PURPOSE: To quantify the breakdown of the blood-aqueous barrier (BAB) following phacoemulsification with posterior chamber lens implantation in eyes with Fuchs' heterochromic uveitis (FHU). PATIENTS AND METHODS: In this retrospective study, 19 eyes of 19 patients with FHU (mean age 38 +/- 14 years) and 35 eyes of 35 patients with senile cataracts (mean age 63 +/- 9 years) underwent phacoemulsification with one-piece PMMA posterior chamber lens implantation. Aqueous flare was quantified using the laser flare-cell meter (LFCM, Kowa FC-1000) following medical pupillary dilation preoperatively and 1, 3, and 5 days, then 1 and 6 weeks and 6 months postoperatively. RESULTS: Mean preoperative aqueous flare (in photon counts per millisecond) in FHU vs. controls was 11.7 +/- 3.5 vs. 5.8 +/- 1.7. Following cataract surgery, mean aqueous flare increased to 27.8 +/- 4.4 vs. 16.0 +/- 4.5 on day 1, decreased to 23.6 +/- 4.0 vs. 11.8 +/- 3.5 on day 3, and to 18.0 +/- 3.0 vs. 9.5 +/- 1.7 on day 5. In FHU eyes, it was 13.9 +/- 2.7 after 1 week, and had returned to preoperative levels after 6 weeks (10.9 +/- 2.5) and remained stable for up to 6 months (mean 10.3 +/- 2.2). Pre- and postoperatively, aqueous flare values were 2-3 times higher in FHU eyes than in control eyes with senile cataract (p = 0.01). No postoperative complications such as fibrin formation, synechiae, macrophages on the intraocular lens optic or endophthalmitis were observed in any of the patients. CONCLUSIONS: BAB breakdown following phacoemulsification with posterior chamber lens implantation is relatively mild in eyes with FHU and the BAB appears to be fully reestablished to preoperative levels 6 weeks postoperatively, explaining the usually good outcome of cataract surgery in this condition.

Tapioca melanoma of the iris mimicking a vascular tumour: a clinicopathological correlation.

Although vascular iris processes are usually benign, they may be a clinical manifestation of iris melanoma, and this should be considered in the differential diagnosis. The case is reported of a 20-year-old man with a highly vascularized tapioca melanoma of the left iris without involvement of the anterior chamber angle or ciliary body, but with observed growth tendency. Sector iridectomy was performed 2 months after first examination. In addition, two separate floating tumour nodules were observed in the anterior chamber angle at 6 o'clock and were removed by aspiration. After 1 year follow up, no recurrence of melanoma cells was observed. In tapioca iris melanomas, diagnostic differentiation from congenital, inflammatory, vascular and neoplastic iris processes is required. Careful biomicroscopic examination of the iris in patients with vascular iris tumours may help the ophthalmologist to identify malignant iris melanomas (tapioca type) and plan appropriate surgical treatment.

Frequency-doubling perimetry in patients following penetrating keratoplasty.

PURPOSE: Perimetry using a frequency-doubling technique (FDT perimetry) is becoming established as a new diagnostic tool to detect early visual field losses. The aim of this study was to evaluate the diagnostic usefulness of an FDT perimetry protocol (C-20-5) in patients after penetrating keratoplasty (PK) and to assess whether this method is influenced by postoperative corneal topographic changes. METHODS: Thirty-six patients (age 40 +/- 13, median 41 years) following PK and 68 age-matched controls were included in this study. The postoperative interval was 21 +/- 19, median 14 months. Patients with preexisting glaucoma or any postoperative intraocular pressure elevation were excluded. The indications for PK were keratoconus in 82%, Fuchs dystrophy in 15%, and secondary bullous keratopathy in 3%. In 19 patients keratoplasty was performed in 1 eye. FDT perimetry was evaluated in both eyes to judge intraindividual variability. FDT perimetry was done using the screening strategy, which begins testing at the normal 5% probability level. If a stimulus is not detected, further targets are presented. FDT viewfinder and statistics software were used for case-wise recalculation of all missed localized probability levels. RESULTS: Neither mean overall FDT score (0.8 +/- 1.9, median 0.0 versus 0.9 +/-1.0, median 0.0) nor total test time (44 +/- 4.7, median 44 versus 44 +/- 4.2, median 42 seconds) showed significant differences between patients after PK and controls (P = 0.5). There was also no significant difference of mean FDT score between eyes after keratoplasty (0.8 +/- 1.9, median 0.00) and nonoperated contralateral eyes (0.9 +/- 2.0, median 0.00, P = 0.8) in the same patient. No significant correlation between FDT score and visual acuity as well as corneal keratometric astigmatism could be found in patients after PK and in normals (r < 0.2, P = 0.3). In patients after PK, FDT score and examination time were statistically independent of keratometric astigmatism (P = 0.7), topographic astigmatism (P = 0.4), spherical equivalent (P = 0.5), central corneal thickness (P = 0.7), and interval of postoperative follow-up (P = 0.6). CONCLUSIONS: Perimetry using the FDT protocol (C-20-5) seems to be feasible in patients after PK and does not depend on postoperative topographic changes of the cornea. This method allows valid information on visual field abnormality in patients after PK The results indicate that this method may be helpful as a supplement to detect early glaucomatous damage in patients after PK.

Pseudoexfoliation syndrome: pathological manifestations of relevance to intraocular surgery.

Pseudoexfoliation syndrome (PEX) is a common ocular condition often associated with the need for intraocular surgery. Although results of cataract and glaucoma filtering surgery in eyes with PEX in the early stages of the disease may be comparable to those in eyes without PEX, in the later stages morbidity is significantly increased due to periocular surgical complications and the outcome is worse. Surgical and postoperative difficulties are often multifactorial and are directly related to the pathological changes of PEX on intraocular structures. Recent years have seen a large increase in the understanding of the effects of PEX on the various ocular tissues. Although the visible areas of the anterior capsule are most obviously involved, this is only a small part of the picture and of least significance. Biomicroscopically invisible changes of the zonules and their attachments are of greatest consequence. There is also distinct, often active, involvement of almost all tissues of the anterior segment of the eye, many of which have important implications for the anterior segment surgeon including iridopathy, iris vasculopathy (including persistent breakdown of the blood-aqueous barrier and anterior segment hypoxia), ciliary body involvement and keratopathy. Trabecular dysfunction is evident by the deposition of PEX material derived from both in situ and extra-trabecular production as well as protein and melanin deposition. These changes should be kept in mind by all intraocular surgeons as a source of potential difficulties in the perioperative period. Additionally, in light of these changes, patients need to be given realistic expectations regarding the increased risk of complications and more prolonged expected recovery time. In this short review, current reports relating to PEX pathological changes of practical interest to the intraocular surgeon are summarized.

Comparison of 6-month results of implantation of the 1CU accommodative intraocular lens with conventional intraocular lenses.

OBJECTIVE: To evaluate the clinical results of implantation of the new 1CU accommodative intraocular lens (IOL) in cataract patients and to compare results with those of conventional IOLs. DESIGN: Nonrandomized comparative trial. PARTICIPANTS: Twenty eyes of 20 patients (mean age = 65.8+/-13.3 years) in the 1CU group and 20 eyes of 20 patients (mean age = 67.4+/-11.6 years) in the control group. METHODS: All patients underwent phacoemulsification and IOL implantation. The 1CU accommodative lens was used in 20 eyes, and conventional IOLs (polymethyl methacrylate, hydrophilic or hydrophobic acrylate) were used in the control group. Patients were observed prospectively, and 6-month data were analyzed. MAIN OUTCOME MEASURES: Accommodative ranges determined by 3 different methods (near point, defocusing, and retinoscopy). Secondary outcome measures were (1) increase of anterior chamber depth after topical application of 1% cyclopentolate eyedrops and (2) distance-corrected near visual acuity with Birkhäuser reading charts at 35 cm. RESULTS: We observed a higher accommodative range with all 3 methods (mean = 1.83+/-0.49 vs. 1.16+/-0.27 diopters [D] [near point], 1.85+/-0.43 vs. 0.64+/-0.21 D [defocusing], and 0.98+/-0.55 vs. 0.17+/-0.22 D [retinoscopy]), a larger increase of anterior chamber depth after cyclopentolate eyedrops (mean = 0.42+/-0.18 vs. 0.11+/-0.06 mm), and better distance-corrected near visual acuity (median = 0.4 vs. 0.2) in the 1CU group relative to the control group. All differences between the 2 groups were statistically highly significant (P<0.001). CONCLUSIONS: In the present study, the 1CU accommodative IOL showed increased accommodative range and better near visual acuity than a control group with conventional IOLs. Further research is necessary to confirm these results in masked, randomized, prospective studies and to confirm further the accommodative power of this group of new IOLs.

Theoretical and measured pseudophakic accommodation after implantation of a new accommodative posterior chamber intraocular lens.

OBJECTIVE: To analyze different techniques of measuring accommodation after implantation of a new accommodative posterior chamber intraocular lens (PCIOL). METHODS: In this comparative, nonrandomized interventional study, we analyzed 15 eyes of 15 patients (aged 44-84 years) at 6 months after cataract surgery and PCIOL implantation (Akkommodative 1CU; HumanOptics AG, Erlangen, Germany) and compared these results with those of an age-matched control group (n = 15). We used the following methods to measure accommodation: dynamic measurement with objective (videorefractometry [PowerRefractor; PlusOptix, Erlangen] and streak retinoscopy) and subjective (subjective near point [push-up test and accommodometer] and defocusing) techniques, as well as static measurement of the change in anterior chamber depth (ACD) using the IOLMaster (Zeiss, Jena, Germany) after pharmacological stimulation using 2% pilocarpine eye drops. MAIN OUTCOME MEASURES: Theoretical accommodation calculated from the forward shift of the lens optics (decrease of ACD) using paraxial geometrical optics and measured accommodation amplitude. RESULTS: Accommodation amplitude (mean +/- SD; range; median) results after 6 months in the study and control groups were as follows: 1.00 +/- 0.44; 0.75-2.13; 1 diopter (D); and 0.35 +/- 0.26; 0.10-0.65; 0.25 D, respectively, using the PowerRefractor; 0.99 +/- 0.48; 0.13-2.00; 0.88 D; and 0.24 +/- 0.21; -0.13-0.75; 0.25 D, respectively, using retinoscopy; 1.6 +/- 0.55; 0.50-2.56; 1.7 D; and 0.42 +/- 0.25; 0.00-0.75; 0.50 D, respectively, using subjective near point; and 1.46 +/- 0.53; 1.00-2.50; 1.75 D; and 0.55 +/- 0.33; 0.25-0.87; 0.50 D, respectively, using defocusing. Anterior chamber depth decreased in the study and control groups as follows: 0.78 +/- 0.12; 0.49-1.91; 0.65 mm; and 0.16 +/- 0.09; 0.00-0.34; 0.18 mm, respectively, after applying 2% pilocarpine eyedrops, indicating an accommodation of 1.16 +/- 0.22; 0.72-1.88; 1.05 D vs 0.22 +/- 0.13; 0.00-0.47; 0.23 D (P =.001). CONCLUSIONS: Accommodation after implantation of a presumably accommodative PCIOL can be measured with clinical methods or derived from the biometric data of the eye and the measured ACD decrease using geometrical optics. For clinical purposes, pseudophakic accommodation should be assessed with a variety of different techniques, including subjective and objective measurements. The theoretical approach using geometrical optics may be an additional indicator for the accommodative response in patients with pseudophakic eyes and may allow a subdivision of the measured accommodation into true pseudophakic accommodation and pseudoaccommodation.

Impact of graft diameter on corneal power and the regularity of postkeratoplasty astigmatism before and after suture removal.

OBJECTIVE: To assess the impact of graft diameter on corneal curvature before and after removal of a double-running suture after nonmechanical penetrating keratoplasty (PK). DESIGN: Prospective, nonrandomized, comparative (self-controlled) single-center clinical trial. PATIENTS: Four hundred eighty-nine eyes with "two sutures in" and 308 eyes with "all sutures out" (mean age, 52+/-19 years) were included. The diagnoses were keratoconus (48%), Fuchs' and stromal dystrophies (31%), aphakic or pseudophakic bullous keratopathy (11%), and scars (10%). INTERVENTIONS: In all eyes, a central trephination was performed (donor trephination from the epithelial side) using the 193-nm Meditec excimer laser (Carl Zeiss Meditec, Jena, Germany) along metal masks with eight "orientation teeth/notches." Diameters were 8.0 mm, 7.5 mm, and 7.0 mm with a graft oversize of 0.1 mm. In 29% of eyes, additional cataract, intraocular lens surgery, or both were performed simultaneously. In all eyes, a double-running 10-0 nylon suture was applied. Zeiss keratometry and TMS-1 topography analysis were performed before removal of the first suture (14+/-4 months) and at least 6 weeks after removal of the second suture (20+/-4 months), but before any additional surgery, such as cataract extraction or refractive keratotomies. MAIN OUTCOME MEASURES: Topographic central corneal power (CP; keratometric diopters), keratometric astigmatism (KA), surface regularity index (SRI), and surface asymmetry index (SAI). The regularity of keratometry mires was recorded semiquantitatively from 0 = regular to 3 = not measurable (as published earlier). RESULTS: With both sutures in, median CP in 7.0-mm (42.0 diopters [D]; P = 0.04) and in 7.5-mm grafts (42.3 D; P = 0.007) was significantly lower than in 8.0-mm grafts (43.0 D). Keratometric astigmatism did not differ between groups (3.0 D vs. 3.0 D vs. 2.7 D). The SRI (1.66 vs. 1.43 vs. 1.11) and SAI (1.55 vs. 1.24 vs. 0.85) decreased significantly with increasing diameter. The proportion of regular keratometry mires (13% vs. 17% vs. 29%) increased, and the proportion of not measurable keratometries (45% vs. 18% vs. 9%) decreased with increasing diameter. With all sutures out, CP in 7.0-mm grafts (40.4 D) was significantly smaller than in 7.5-mm (43.6 D; P = 0.04) and 8.0-mm grafts (43.3 D; P = 0.04). Again, KA did not differ between groups (3.0 D vs. 3.2 D vs. 3.0 D). The SRI (1.40 vs. 1.09 vs. 0.84) and SAI (1.24 vs. 0.83 vs. 0.62) decreased significantly with increasing diameter. The proportion of regular keratometry mires (5% vs. 31% vs. 52%) increased, and the proportion of not measurable keratometries (42% vs. 11% vs. 4%) decreased with increasing diameter. CONCLUSIONS: After PK, a smaller graft diameter results in a flatter curvature and a higher degree of topographic irregularity, but not in higher net astigmatism. After suture removal, graft topography tends to regularize, whereas the principal differences between diameters do persist.

Nonmechanical Q-switched erbium:YAG laser trephination for penetrating keratoplasty: experimental study on human donor corneas.

OBJECTIVE: To assess the alterations in human donor corneal tissue induced by Q-switched erbium (Er):YAG laser corneal trephination. METHODS: Thirty human corneoscleral donor buttons unsuitable for transplantation were placed in an artificial chamber on an automated rotation device. Corneas were trephined with a Q-switched Er:YAG laser (wavelength, 2.94 microm; pulse duration, 400 nanoseconds) along (donor and recipient) aluminum silicate (ceramic) open masks. A spot diameter of 0.65 mm, energy setting of 50 mJ/pulse, and repetition rate of 5 Hz were used. Corneal thermal damage and cut regularity were quantitatively assessed in 24 corneas processed for light microscopy and by transmission and scanning electron microscopy. RESULTS: The stromal thermal damage was the highest (mean [SD], 8.0 [2.7] microm) at a 150-microm cut depth and decreased downward. Cut regularity was very good and did not significantly differ between donors and recipients. Scanning electron microscopy confirmed that the cuts were highly regular; transmission electron microscopy revealed 2 distinctive subzones within the stromal thermal damage zone. CONCLUSIONS: Thermal damage induced by Q-switched Er:YAG nonmechanical corneal trephination was low, and the regularity of the cuts was very good. CLINICAL RELEVANCE: The Q-switched Er:YAG laser may have the potential to become an alternative to the excimer laser for nonmechanical penetrating keratoplasty.

Corneal shrinkage induced by nonmechanical Q-switched erbium:YAG laser trephination for penetrating keratoplasty in porcine eyes.

PURPOSE: To assess the degree of corneal diameter shrinkage induced by Q-switched mid-infrared laser corneal trephination for penetrating keratoplasty in an experimental model. METHODS: Corneal trephination was performed in 80 enucleated porcine eyes fixed in a holder centered on an automated globe rotation device, by Q-switched (2.94 microm) Er:YAG laser along open masks. Four types of masks were used to protect the underlying corneal tissue: metal masks (donor and recipient) and ceramic masks (donor and recipient). Two spot diameters (0.65 mm and 0.96 mm) were combined with two energy settings (40 mJ/pulse and 50 mJ/pulse) for each of the masks used. Repetition rate was fixed at 5 Hz. Diameters of donor buttons/recipient beds (horizontal and vertical) were measured immediately after the trephination and compared to the given mask size. RESULTS: Minimum corneal shrinkage was found in the recipient metal mask group (mean +/- SD=0.3+/-0.4%) with 50 mJ pulse energy and 0.65 mm spot diameter (in the horizontal diameter), while the maximum shrinkage (5.3+/-2.8%) was found in the donor metal mask group with 50 mJ pulse energy and 0.96 mm spot diameter. Corneal shrinkage was less pronounced in recipient beds than in donor buttons (P<0.01). The differences in shrinkage between the use of ceramic and metal masks were insignificant (P>0.05). Mean induced corneal diameter discrepancies between the donor button and the recipient bed (with metal and ceramic masks) were 2.5% and 2.5% in vertical diameter and 3.4% and 2.4% in horizontal diameter. CONCLUSIONS: The Q-switched Er:YAG laser experimental corneal trephination for penetrating keratoplasty may induce minor degrees of corneal diameter shrinkage in donor buttons and recipient openings. Oversizing of donor masks by 0.25-0.35 mm (i.e. 3-4% of graft size) may be a valid option to avoid refractive consequences.

Results and complications of hydrophobic acrylic vs PMMA posterior chamber lenses in children under 17 years of age.

PURPOSE: To compare results and complications of implantation of hydrophobic acrylic foldable intraocular lenses in children with those of polymethylmethacrylate (PMMA) intraocular lenses. METHODS: In a retrospective study, we analyzed results of cataract surgery with posterior chamber lens implantation in 30 eyes of 30 patients aged 1-16 years. In 10 eyes, acrylic (Alcon AcrySof) intraocular lenses, and in 20 eyes, single-piece PMMA posterior chamber lenses were implanted. Indications for cataract surgery (blunt or penetrating trauma, zonular cataract, cataracta polaris posterior, posterior lenticonus) and mean age at implantation were comparable in the two groups. Mean patient age at surgery was 8.6+/-4.6 years (range 3-16 years) for the acrylic vs 6.3+/-4.3 years (range 1-16 years) for the PMMA group. Mean follow-up was 1.0+/-0.7 years (range 0.1-2.2 years) in the acrylic group and 1.8+/-1.5 years (range 0.1-5.7 years) in the PMMA group. Primary anterior vitrectomy was performed in 7 eyes in the PMMA group and in 3 eyes in the acrylic group. In addition, one additional posterior capsulorhexis without anterior vitrectomy was performed in each group. Primary outcome measure was the occurrence of postoperative "complications" (fibrin, synechiae, posterior capsular opacification). For statistical evaluation, the Fisher exact test was used. RESULTS: When evaluating all complications together (at least one complication vs no complication), there were significantly less complications in the acrylic group (2 of 10 vs 15 of 20; p=0.007. For early complications (postoperative fibrin, synechiae) the difference was also significant (1 of 10 in the acrylic vs 11 of 20 in the PMMA group; p=0.02). The rate of posterior capsular opacification necessitating YAG capsulotomy was lower in the acrylic group (1 of 10 eyes) than in the PMMA group (7 of 20 eyes), but the difference did not reach statistical significance ( p=0.67). The postoperative time point of YAG capsulotomy was 21 months in the acrylic group and 19+/-10 months (range 6-33 months) in the PMMA group. IOL dislocation was not observed in any of the patients. Postoperative visual acuity was comparable in the two groups: 0.57+/-0.35 (0.03-1.0) in the acrylic vs 0.39+/-0.34 (0.001-0.9) in the PMMA group ( p=0.83). CONCLUSIONS: Implantation of hydrophobic acrylic intraocular lenses in the capsular bag in children may be associated with less postoperative complications compared with implantation of PMMA lenses. This appears also to be true in children under age 6 years. The visual results seem comparable and correspond mainly to the underlying ocular pathology.

[Block excision of epithelial ingrowth after cataract surgery--report on 15 patients]. / Blockexzision der Epithelinvasion nach Kataraktoperation--Bericht über 15 Patienten.

BACKGROUND: Cystic or diffuse epithelial ingrowth into the anterior chamber after cataract surgery is a rare complication. It can lead to painful secondary glaucomas or in case of fistulation to persisting ocular hypotony or atrophy of the globe due to wrong or inadequate therapy. PATIENTS AND METHODS: The cause of epithelial ingrowth was a previous cataract surgery in 15 of 59 patients (25 %, Erlangen Block-Excision Registry for epithelial ingrowth). Eleven patients were females. Mean age was 65 +/- 13 years. RESULTS: Ten patients underwent block excision of epithelium, adjacent iris, ciliary body, sclera or cornea due to epithelial ingrowth following intracapsular cataract extraction between 1980 and 1987 and five patients since 1987 because of epithelial ingrowth following extracapsular cataract extraction (4 with and 1 without intraocular lens implantation); all primary cataract surgeries had been performed in external hospitals. We found a diffuse invasion in 3 eyes (all following icCE) and a cystic epithelial invasion in 12 eyes histologically. Mean time interval between cataract surgery and block excision was 7 +/- 8 years (range: 1 to 33 years). The excisional defect in the globes wall was covered using a tectonic corneoscleral graft (diameter: 8.0 +/- 1.8 mm). Postoperative astigmatism was 3.6 +/- 3.4 dpt. Six eyes had postoperatively a visual acuity of 20/200 or better. No recurrence of epithelial downgrowth was observed, nor was an enucleation needed. CONCLUSION: Surgical procedures with opening of the cyst (e.g. laser) are contraindicated and may lead to a transformation from cystic into diffuse epithelial invasion with potential blindness. The therapy of first choice in eyes with cystic epithelial ingrowth and an extension less than five clock hours is the curative block-excision technique combined with tectonic corneoscleral graft. Surgical results are excellent in order to regard a curative excision and the survival of the eye with acceptable achieved function in consideration of the difficult primary situation with intra- and postoperative complications due to previous cataract surgery.

[Post-traumatic endophthalmitis after penetrating injury in Vietnam: risk factors, microbiological aspect and visual outcome]. / Posttraumatische Endophthalmitis nach perforierender Verletzung in Vietnam: Risikofaktoren, mikrobiologische Aspekte und funktionelle Ergebnisse--Eine retrospektive Analyse.

BACKGROUND: Post-traumatic endophthalmitis associated with penetrating injury represents a distinct kind of intraocular infection and is still a severe problem for diagnosis and treatment in developing countries. We report the incidence, microbiological presentation and visual outcome of post-traumatic endophthalmitis in South Vietnam. PATIENTS AND METHOD: In a retrospective study medical reports of 515 patients with penetrating injury treated at Eye Hospital in Ho Chi Minh city, Vietnam, from 1/1999 to 5/2000 were reviewed and analysed. The treatment was standardised: 1. after vitreous-biopsy intravitreous injection of 0.1 mg/0.1 ml Gentamycine and 1 mg/0.1 ml Vancomycine; 2. subconjunctival injection of 25 mg/0.5 ml Vancomycine and 20 mg/0.5 ml Gentamycine; 3. topical and systemic antibiotic treatment due to microbiological presentation; 4. systemic steroids treatment. Clinical parameters were evaluated for association with an increased risk of endophthalmitis. RESULTS: Out of 515 patients with penetrating injury 61 patients (11.8 %) with endophthalmitis were treated and evaluated. Mean time interval from trauma to diagnosis of endophthalmitis was 16.8 +/- 5.6 days. Follow-up period was 15.6 +/- 23.4 days. Visual acuity at the diagnosis of endophthalmitis in 96 % of all patients was only finger counting or light perception. Enucleation was needed in 14 % of patients, 29 % of patients developed phthisis bulbi. A visual acuity better than finger counting was reached in only 10 % of all patients with endophthalmitis. Cultures of the vitreous aspirate were positive in only 50 % of cases available and showed Gram-positive (51 %), Gram-negative bacteria (33 %) and fungi (16 %). Risk factors found to be significant were: 1. a purely corneal wound; 2. wound length less than 5 mm; 3. surgical primary repair more than 24 hour after trauma; 4. inadequate antibiotic treatment and 5. a rural injury setting. CONCLUSION: Post-traumatic endophthalmitis is still a major problem in Vietnam. Delay in primary wound closure or inadequate antibiotic treatment worsen the prognosis profoundly. Comprehensive prophylactic antibiotic treatment at the time of injury repair is in dispensable. In risk eyes particular attention should be paid to prophylaxis and signs of infection. Further prospective studies are necessary to develop optimal and adequate diagnostic and treatment options in Vietnam.

Q-Switched 2.94-microm Er:YAG laser trephination with convergent and divergent cut angles for penetrating keratoplasty.

PURPOSE: To study the morphologic properties of perpendicular (P), convergent (C), and divergent (D) cut angles using different speeds of rotations during donor and recipient nonmechanical trephination for experimental penetrating keratoplasty. METHODS: With a Q-switched 2.94-microm Er:YAG laser corneal trephination was performed in 150 enucleated porcine eyes using ceramic open masks with 8 "orientation teeth/notches" and an automated globe rotation device allowing different cut angles [0 degree (P), 10 and 20 degrees (C and D)] toward the optical axis and variation of the rotation speed [3, 7, and 11 rotations per minute (rpm)]. The regularity of the cut (I, regular; II, slightly irregular; III, irregular) was assessed by light microscopy. The area of thermal damage and the number and size of "spikes" in the stroma at the superficial, intermediate and deep level of the excision were analyzed using digital images and the Optimas image processing software. RESULTS: The regularity of the cut was classified as I in 42%/22% of donor/recipient and as II in 41%/56%, respectively. The thermal damage was least expressed with D20 degree cut angle and donor mask (P < 0.01). With all cut angles and speeds of rotation, thermal damage at the deep level of excision was significantly smaller (P < 0.01). With different speeds of donor rotations, the thermal damage showed no significant difference. With recipient trephination, the thermal damage at the deep level was greatest with 7 rpm (P < 0.01). The number and size of spikes of thermal damage with donor and recipient masks were significantly smaller in the deep stroma (P < 0.01). CONCLUSIONS: Q-switched Er:YAG laser trephination with appropriate settings results in low thermal damage zones at the cut margin. Different cut angles and speeds of trephination may affect the cut performance and quality of the excision. In our study, low rotation speed and divergent donor cut angles showed the best results. The cut quality and the small thermal damage with the Q-switched 2.94-microm Er:YAG laser seem to be tolerable for corneal trephination. Therefore, this modality may be a low-cost, easy-to-handle alternative for nonmechanical corneal transplantation in humans.

[Impact of intracameral pressure on donor cut angles in nonmechanical Er:YAG laser trephination for penetrating keratoplasty]. / Einfluss des Innendrucks auf die Schnittwinkel in Humanhornhäuten bei der Spendertrepanation mit dem Er : YAG-Laser für die perforierende Keratoplastik.

BACKGROUND AND PURPOSE: Congruent cut surfaces are a predisposition for good apposition of donor and recipient during penetrating keratoplasty (PK). The purpose of this study was to assess the impact of the intracameral pressure during nonmechanical donor trephination from the epithelial side on the cut angles for experimental human PK. METHODS: With a Q-switched 2.94 micro m Er : YAG laser a 6 mm sized corneal donor trephination was performed subtotally in 30 human corneas using an artificial anterior chamber device allowing different intracameral pressures (10, 20, and 40 mm Hg). The cut angles were measured immediately after the trephination by ultrasound biomicroscopy (UBM) at four quadrants: between trephination cut and corneal epithelium (angle 1 = A1-UBM) and between trephination cut and horizontal plane (angle 2 = A2-UBM). The positions of the measures were marked, the corneas were fixed in a buffered 10 % paraformaldehyde solution, and the same positions were analyzed by histology. The histological cuts were digitized, the images printed, and the cut angles measured in paper (A1-histology). RESULTS: Mean angles were 111.6 degrees /113.5 degrees /126.6 degrees (A1-UBM), 88.4 degrees /93.5 degrees /101.8 degrees (A2-UBM) and 120.4 degrees /125.1 degrees /119.3 degrees (A1-histology) with 10/20/40 mm Hg, respectively. The A2-UBM showed a significant increase of divergence with increasing intracameral pressure (p < 0.03). For A1-UBM cut angles with 10 and 20 mm Hg were significantly smaller compared to those with 40 mm Hg (p < 0.002), but there was no difference of divergence between 10 and 20 mm Hg. The A1-histology cut angle showed no correlation with intracameral pressure (p > 0.09). CONCLUSIONS: Increasing intracameral pressure using an artificial anterior chamber during donor trephination from the epithelial side for nonmechanical PK using Er : YAG laser results in increasing divergence of cut angles. This may disturb the congruence of the cut angles in donor-recipient apposition. To achieve standardised cut angles for a good donor recipient apposition, similar normotonic intracameral pressures for donor and recipient trephination should be attempted. The UBM has the potential to analyse the cut angle immediately after subtotal trephination preserving the attempted intracameral pressure in the artificial anterior chamber. Histological analysis of the cut angles seems to lack methodological validity.

[Cataract and keratoplasty--simultaneous or sequential surgery?]. / Katarakt und Keratoplastik--simultane oder sequenzielle Operation?

BACKGROUND AND PURPOSE: Since the introduction of the triple procedure (simultaneous penetrating keratoplasty [PK], extracapsular cataract extraction [CE] and implantation of a posterior chamber intraocular lens [PCIOL]) in the mid-seventies, there is an ongoing discussion among corneal surgeons concerning the best approach for combined corneal disease and cataract. METHODS: Besides the classical triple procedure (1), two alternative microsurgical approaches are feasible: (2) CE + PCIOL prior to PK and (3) CE + PCIOL after PK. For the refractive results after TRIPLE some intraoperative details are crucial: Trephination of recipient and donor from the epithelial side without major oversize (Guided Trephine System or Nonmechanical Excimer Laser Trephination) should preserve the preoperative corneal curvature. Graft and the PCIOL placed in the bag after continuous curvilinear capsulorhexis should be centered along the optical axis. If possible, performing the capsulorhexis under controlled intraocular pressure conditions prior to trephination may help to minimise the risk of capsular ruptures. RESULTS: The major advantage of the TRIPLE is the faster visual rehabilitation and less efforts for the mostly elderly patients. However, two intraocular interventions with approach (2) and (3) bear an increased risk of infection and suprachoroidal haemorrhage. Approach (2) requires a cornea that is still transparent enough to perform cataract surgery, and the risk of intraocular pressure rise after PK seems to be increased. Approach (3) has the potential of a simultaneous reduction of astigmatism during CE (appropriate location of the incision, simultaneous refractive keratotomies or implantation of a toric PCIOL). Disadvantages may include the loss of graft endothelial cells and the theoretically increased risk of immunological allograft reactions. After TRIPLE, major deviations from target refraction have been reported. However, individual multiple regression analysis may help to minimise this problem with appropriate methods of trephination. Since suture removal after PK may result in major individual changes of the corneal curvature, IOL power calculation for approach (3) requires all sutures to be removed at the time of CE. However, even after complete suture removal the abnormal proportions between anterior and posterior curvatures and/or the irregular topographies after PK may be responsible for marked IOL power miscalculations in the individual case. CONCLUSIONS: The postulated better refractive outcome and better uncorrected visual acuity after the sequential approach is opposed by a markedly delayed visual rehabilitation. For this reason, we consider the TRIPLE procedure including CE via open sky in general anesthesia as the method of choice for combined lens and corneal opacities. Because of the often rapidly progressive nuclear cataracts after PK, we recommend the simultaneous approach in elderly patients with Fuchs' dystrophy even with incipient lens opacities.