Modified penetrating keratoplasty with Acell® bioscaffold implant in seven horses with deep full-thickness corneal stromal abscess.

OBJECTIVE: To describe and evaluate a modified penetrating keratoplasty technique utilizing ACell® for management of equine deep stromal or full-thickness corneal stromal abscesses (SA). METHODS: Cases presenting to the University of Georgia Ophthalmology service for surgical management of SA necessitating penetrating keratoplasty (PK) were included in the study population. Surgery entailed the use of an ACell® disk sutured within the deep level of a stepped full-thickness corneal incision with an overlying conjunctival pedicle flap placed in the superficial step incision. Patients were evaluated for success as defined by a comfortable, visual outcome. RESULTS: Surgery was performed in seven horses. Conjunctival flap incorporation and globe retention occurred in all patients. Functional vision was maintained in six of seven eyes (85.7%) at last follow-up examination (mean of 87.6 days [range 41-251 days]). Mean size of ACell® implant was six millimeters (range 4-8 mm). Postoperative complications included moderate to severe anterior uveitis (n = 2), diffuse keratitis (n = 1), incipient cataract formation (n = 3), and anterior and posterior synechiae (n = 1). CONCLUSIONS: This technique is a viable option for treatment of equine SA requiring PK. The use of bioscaffold implant is an alternative to frozen and fresh donor cornea transplantation.

[Objective assessment of donor material for penetrating corneal transplantation]. / Ob''ektivizatsiia otsenki donorskogo materiala dlia skvoznoi peresadki rogovitsy.

Reliable suitability evaluation of donor material is the crucial issue of penetrating corneal transplantation. The main parameter to be considered is endothelial cell density (ECD). However, when it comes to practice, one has to admit significant variation in ECD readings of cadaver corneas obtained by different methods. AIM: to investigate discrepancies in ECD measurements and to define objective criteria for the evaluation of a donor cornea before full-thickness grafting. MATERIAL AND METHODS: In a hundred cadaver eyes, discrepancies in ECD measurements by different methods (specular microscopy, confocal microscopy, and keratoanalyzer) were studied and objective evaluation criteria developed along with an optimal algorithm of pretransplantation assessment. Digital fluorescence microscopy was chosen as the reference method. RESULTS: It has been established that a triple measurement average obtained with any of the tested methods is informative enough as to the state of the donor cornea. CONCLUSION: The highest ECD values were obtained with specular microscopy, the lowest - with confocal microscopy. For reliable evaluation of donor corneas, we recommend that the average of a triple ECD measurement be taken using one of the mentioned methods.

Eye-tracker-guided non-mechanical excimer laser assisted penetrating keratoplasty.

PURPOSE: The purpose of the study was to implement a new eye tracking mask which could be used to guide the laser beam in automated non-mechanical excimer laser assisted penetrating keratoplasty. MATERIALS AND METHODS: A new trephination mask design with an elevated surface geometry has been proposed with a step formation between conical and flat interfaces. Two recipient masks of 7.5/8.0 mm have been manufactured and tested. The masks have outer diameter of 12.5 mm, step formation at 10.5 mm, and slope of conical surfaces 15°. Its functionality has been tested in different lateral positions and tilts on a planar surface, and pig eye experiments. After successful validation on porcine eyes, new masks have been produced and tested on two patients. RESULTS: The build-in eye tracking software of the MEL 70 was always able to capture the masks. It has been shown that the unwanted pigmentation/pattern induced by the laser pulses on the mask surface does not influence the eye-tracking efficiency. The masks could be tracked within the 18 × 14 mm lateral displacement and up to 12° tilt. Two patient cases are demonstrated. No complications were observed during the surgery, although it needs some attention for aligning the mask horizontally before trephination. Stability of eye tracking masks is emphasized by inducing on purpose movements of the patient head. CONCLUSION: Eye-tracking-guided penetrating keratoplasty was successfully applied in clinical practice, which enables robust tracking criteria within an extended range. It facilitates the automated trephination procedure of excimer laser-assisted penetrating keratoplasty.

Effects of femtosecond laser-assisted trephination on donor tissue in liquid interface as compared to applanated interface.

PURPOSE: To evaluate the effects of femtosecond laser-assisted keratoplasty using a liquid patient interface (L-PI) as opposed to an applanated interface (A-PI) on graft quality and functionality markers. METHODS: Pressure measurements during femtosecond laser-assisted trephination were performed using two groups of 10 porcine eyes. Trephination was performed either in an L-PI or in an A-PI setting. Pressure sensor needles placed intravitreally continuously recorded intraocular pressure during trephination. Twenty paired human donor eyes were used to test the morphological quality of donor tissue after trephination in L-PI and A-PI settings. Optical coherence tomography (OCT) scans were performed before and after trephination. Images were processed using ImageJ and pixel2 . RESULTS: During trephination, pressure measurements with an L-PI were significantly lower than with an A-PI (p = 0.0121). Mean pressure during trephination was 78.1 mmHg ± 37.6 mmHg with L-PI and 188.6 mmHg ± 17.7 mmHg with A-PI. Trephination in A-PI produced a significantly larger increase (p < 0.00001) in donor pachymetry than trephination in L-PI. Significantly lower areas of Descemet folds were achieved in L-PI trephination than in A-PI trephination (p < 0.01). There was no significant difference in circularity between A-PI and L-PI (p = 0.27). Total time required for trephination was comparable between L-PI and A-PI (p = 0.45). Time taken to reach working vacuum was achieved significantly more quickly in L-PI (p < 0.05). CONCLUSION: Femtosecond laser-assisted L-PI keratoplasty appears to be a promising method to decrease stress to donor and recipient tissue during femtosecond laser-assisted trephination. Results showed favourable donor tissue morphology markers after L-PI trephination.

Comparison of femtosecond laser-assisted keratoplasty versus conventional penetrating keratoplasty.

PURPOSE: To compare postoperative outcomes for femtosecond laser-assisted keratoplasty (FLAK) with conventional penetrating keratoplasty (PK). DESIGN: Retrospective, comparative surgical series. PARTICIPANTS: Fifty consecutive patients who underwent FLAK and 50 case-controlled patients that had PK at the Casey Eye Institute (Oregon Health & Science University, Portland, OR). METHODS: Data was collected for 50 consecutive cases that underwent zigzag incision FLAK and was compared with 50 subjects that had conventional blade trephine incision PK with similar age, diagnosis and concurrent ocular morbidities over a 2-year follow-up period. MAIN OUTCOME MEASURES: Topographic astigmatism, best spectacle-corrected visual acuity, uncorrected visual acuity, pinhole visual acuity, and the timing of selective suture removal (or adjustment) over various follow-up intervals up to 2 years postoperatively. RESULTS: Significantly lower topographic astigmatism was achieved in the FLAK group over the PK group in the 4- to 6-month follow-up period (P = 0.0324), which correlated well with significant earlier selective suture removal that occurred in that same group over both the 2- to 3-month (P = 0.0025) and 4- to 6-month (P = 0.0236) follow-up periods. This difference in astigmatism was no longer present at any other follow-up period up to 24 months postoperatively. The subset analysis of patients with keratoconus or post-LASIK ectasia did not show any difference in either astigmatism or visual acuity at any time. CONCLUSIONS: Compared with PKP, FLAK had significant improvement in astigmatism before but not after the 6 month postoperative follow-up period. Earlier suture removal was noted in the FLAK group. No significant improvement in best spectacle-corrected visual acuity was noted at any time point. There were no complications or difficulties with trephination in the FLAK procedure across a wide range of corneal pathologies.

[Therapeutic applications of the femtosecond laser in corneal surgery]. / Therapeutischer Einsatz des Femtosekundenlasers in der Hornhautchirurgie.

Since 2001 the femtosecond laser has primarily been used in refractive surgery, e. g., for lasik, implantation of intracorneal ring segments or antiastigmatic corneal incisions. However, the femtosecond laser is more and more used for therapeutic reasons in corneal surgery. In this context it is used for profiled trephinations in penetrating keratoplasty where various profiles of the cutting edge can be designed (e. g., top-hat profile, mushroom profile, zig-zag profile). The potential advantages of these profiles include improved graft adaptation, better and more stable wound healing leading to earlier suture removal and eventually prolonged graft survival. However, none of these potential advantages has been demonstrated by reliable study results until now. First clinical experiences show that much earlier suture removal is possible without significant complications. However, with sutures in there seems to be no advantage of the femtosecond laser compared to mechanically guided trephination systems regarding visual acuity and postoperative astigmatism. Besides penetrating profiles, the femtosecond laser also allows for lamellar cuts. As deep anterior lamellar keratoplasty can only be supported by the femtosecond laser, it is mostly used for posterior lamellar grafts in this context. However, first clinical results using the femtosecond laser for DSAEK (descemet stripping automated endothelial keratoplasty) are poorer than those using microkeratome-prepared lamellar grafts for DSAEK.

Comparison of penetrating keratoplasty performed with a femtosecond laser zig-zag incision versus conventional blade trephination.

PURPOSE: To evaluate visual outcomes and astigmatism in patients who underwent penetrating keratoplasty (PK) with 2 different incision techniques. DESIGN: Retrospective comparison of a consecutive surgical series. PARTICIPANTS: Fifty-seven consecutive patients who underwent PK at the University of California, Irvine, academic referral practice. METHODS: A comparison of 49 eyes of 43 patients that underwent femtosecond laser zig-zag incision pattern PK versus 17 eyes of 14 patients that underwent conventional Barron suction trephination PK performed contemporaneously. All PKs were closed with an identical, 24-bite running nylon suture technique. MAIN OUTCOME MEASURES: Topographically determined astigmatism, best spectacle-corrected visual acuity (BSCVA), and recovery of full visual potential. RESULTS: The postoperative follow-up ranged from 1 to 12 months. There was a significant difference in average astigmatism between the groups at postoperative month 1 (P = 0.013) and 3 (P = 0.018). By month 3, the average astigmatism was 3 diopters (D) in the zig-zag group and 4.46 D in the conventional group. Of the patients with normal macular and optic nerve function (n(ZZ) = 32; n(con) = 14), a significant difference in BSCVA was seen at month 1 (P = 0.0003) and month 3 (P = 0.006) with 81% of the zig-zag group versus 45% of the conventional group achieving BSCVA of > or =20/40 by month 3 (P = 0.03). CONCLUSIONS: The femtosecond laser generated zig-zag-shaped incision results in a more rapid recovery of BSCVA and induces less astigmatism compared with conventional blade trephination PK. FINANCIAL DISCLOSURE(S): Proprietary commercial disclosure may be found after the references.

Management of Descemet Membrane's Folds After Deep Anterior Lamellar Keratoplasty: Descemet Membrane-Tucking Technique.

PURPOSE: To describe a surgical maneuver that allows for correction of central Descemet membrane (DM) folds at the end of a deep anterior lamellar keratoplasty (DALK) procedure. We term the present technique "DM tucking." METHODS: A blunt tip spatula is introduced vertically into the trephination cut, 90 degrees away from the main direction of the DM folds, and advanced until it touches the host layer. Gentle pressure is applied, resulting in tucking of the redundant host layer toward the periphery. The tucking maneuver is repeated at different clock hours until a regular graft-host interface is obtained. RESULTS: We applied the present technique to several DALK procedures performed for keratoconus, and found it to be safe and effective. CONCLUSIONS: DALK is the procedure of choice for the surgical treatment of corneal stromal diseases with a healthy endothelium, such as keratoconus. DM folds are a possible complication after DALK in patients with advanced corneal ectasia, arising from the compression of the redundant host DM by the donor graft, once it is sutured to the recipient. DM folds after DALK, when they involve the visual axis, cause permanent visual disturbances DM tucking allows the displacement of the central DM folds toward the graft margin, where they do not affect the patient's quality of vision.

Comparison of Excimer Laser Versus Femtosecond Laser Assisted Trephination in Penetrating Keratoplasty: A Retrospective Study.

INTRODUCTION: To compare the impact of non-mechanical excimer-assisted (EXCIMER) and femtosecond laser-assisted (FEMTO) trephination on outcomes after penetrating keratoplasty (PK). METHODS: In this retrospective study, 68 eyes from 23 females and 45 males (mean age at time of surgery, 53.3 ± 19.8 years) were included. Inclusion criteria were one surgeon (BS), primary central PK, Fuchs' dystrophy (FUCHS) or keratoconus (KC), no previous intraocular surgery, graft oversize 0.1 mm and 16-bite double running suture. Trephination was performed using a manually guided 193-nm Zeiss Meditec MEL70 excimer laser (EXCIMER group: 18 FUCHS, 17 KC) or 60-kHz IntraLase™ femtosecond laser (FEMTO group: 16 FUCHS, 17 KC). Subjective refractometry (trial glasses) and corneal topography analysis (Pentacam HR; Casia SS-1000 AS-OCT; TMS-5) were performed preoperatively, before removal of the first suture (11.4 ± 1.9 months) and after removal of the second suture (22.6 ± 3.8 months). RESULTS: Before suture removal, mean refractive/AS-OCT topographic astigmatism did not differ significantly between EXCIMER and FEMTO. After suture removal, mean refractive/Pentacam/AS-OCT topographic astigmatism was significantly higher in the FEMTO (6.2 ± 2.9 D/7.1 ± 3.2 D/7.4 ± 3.3 D) than in the EXCIMER patients (4.3 ± 3.0 D/4.4 ± 3.1 D/4.0 ± 2.9 D) (p ≤ 0.005). Mean corrected distance visual acuity increased from 0.22 and 0.23 preoperatively to 0.55 and 0.53 before or 0.7 and 0.6 after suture removal in the EXCIMER and FEMTO groups, respectively. Differences between EXCIMER and FEMTO were only pronounced in the KC subgroup. CONCLUSION: Non-mechanical EXCIMER trephination seems to have advantages regarding postoperative corneal astigmatism and visual acuity compared with FEMTO trephination, especially in KC. A bigger sample size and longer follow-up are needed to evaluate the long-term impact of EXCIMER and FEMTO trephination on postoperative topographic and visual outcomes.

Three-Dimensional Optical Coherence Tomography Imaging For Glaucoma Associated With Boston Keratoprosthesis Type I and II.

PRECIS: Three-dimensional (3D) spectral domain optical coherence tomography (OCT) volume scans of the optic nerve head (ONH) and the peripapillary area are useful in the management of glaucoma in patients with a type I or II Boston Keratoprosthesis (KPro). PURPOSE: The purpose of this study was to report the use of spectral domain OCT in the management of glaucoma in patients with a type I or II Boston KPro. MATERIALS AND METHODS: This study is an observational case series. Four consecutive patients with KPro implants were referred for glaucoma evaluation. A comprehensive eye examination was performed which included disc photography, visual field testing, and high-density spectral domain OCT volume scans of the ONH and the peripapillary area. 2D and 3D parameters were calculated using custom-designed segmentation algorithms developed for glaucoma management. RESULTS: Spectral domain OCT parameters provided useful information in the diagnosis and management of 4 KPro patients. OCT parameters which can be used in KPro patients included 2D retinal nerve fiber layer (RNFL) thickness, 3D peripapillary RNFL volume, 3D peripapillary retinal thickness and volume, 3D cup volume, and 3D neuroretinal rim thickness and volume. In 3 of 4 cases where the traditional 2D RNFL thickness scan was limited by artifacts, 3D spectral domain OCT volume scans provided useful quantitative objective measurements of the ONH and peripapillary region. Therefore, 3D parameters derived from high-density volume scans as well as radial scans of the ONH can be used to overcome the limitations and artifacts associated with 2D RNFL thickness scans. CONCLUSIONS: Spectral domain OCT volume scans offer the possibility to enhance the evaluation of KPro patients with glaucoma by using both 2D and 3D diagnostic parameters that are easily obtained in a clinic setting.

Short-term results of penetrating keratoplasty performed with the Femtec femtosecond laser.

PURPOSE: To evaluate the use of the Femtec femtosecond (fs) laser for penetrating keratoplasty (PK) in the treatment of corneal diseases. DESIGN: Prospective, nonrandomized clinical study. METHODS: Nine eyes of nine patients underwent surgery for PK. Five had pseudophakic bullous keratopathy, three had Fuchs dystrophy, and one presented in a keratoconus patient. A Femtec (20/10 PerfectVision; GmbH, Heidelberg, Germany) fs laser was used to create penetrating cuts on donor and recipient corneas. All patients were evaluated for uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), pachymetry, topography, and endothelial cell density (ECD). Scanning electron microscopy (SEM) was performed on corneal tissue after surgery. RESULTS: All eyes were treated successfully without intraoperative complications. The mean follow-up was 6 +/- 3 months. At the last postoperative examination mean BSCVA was 20/69 and there was a significant improvement (P = .08) in both UCVA and BSCVA. Mean astigmatism was 2.9 +/- 1.2 diopters. Mean ECD was 1194 +/- 465 cells/mm(2) with a mean cell loss after surgery of 49.8% +/- 19.8%. SEM displayed smooth rectilinear cut margins and minor remaining tissue bridges. One patient presented a retinal detachment three months after surgery that was successfully treated and two subjects showed an allograft rejection. CONCLUSION: Use of the Femtec fs laser was effective and safe to perform PK. Short-term visual results and refractive results are analogous to conventional PK or other fs laser-assisted PK studies. Longer-term follow-up of additional cases is necessary to precisely quantify the endothelial cell loss after fs surgery.

[Penetrating keratoplasty with intrastromal corneal ring. A prospective randomized study]. / Perforierende Keratoplastik mit intrastromalem Hornhautring. Eine prospektive randomisierte Studie.

BACKGROUND: The purpose of the study was to evaluate the efficacy and safety of Krumeichs' intrastromal corneal ring following penetrating keratoplasty. Postoperative astigmatism and occurrence of complications were the main criteria of this study. MATERIAL AND METHODS: A total of 20 patients were included in this prospectively randomized study (10 patients with and 10 patients without corneal ring). Follow-up examinations were performed 6 weeks, 4, 12, and 18 months postoperatively, including best corrected visual acuity and Orbscan corneal topography. RESULTS: The mean follow-up time is currently 18.9+/-2.8 months. The mean astigmatism (Orbscan) is 3.9 D in the group with ring and 4.0 D in the group without a ring. Spontaneous suture rupture occurred in five patients with corneal ring. CONCLUSIONS: The use of the intrastromal corneal ring following penetrating keratoplasty caused no reduction of postoperative astigmatism. The reason for the spontaneous suture ruptures is unclear.

Elliptical nonmechanical corneal trephination: intraoperative complications and long-term outcome of 42 consecutive excimer laser penetrating keratoplasties.

PURPOSE: To assess intraoperative complications and long-term outcome of elliptical excimer laser trephination for penetrating keratoplasties (EELPKs) performed at the Friedrich-Alexander University of Erlangen, between 1989 and 2002. METHODS: This was a retrospective, longitudinal, single-center, clinical, interventional case series. Forty-two eyes (14 Fuchs dystrophy, 11 corneal ulcer, 7 aphakic/pseudophakic bullous keratopathy, 9 corneal scars, 1 keratotorus) after EELPK were observed. Trephination was performed with a 193-nm Meditec excimer laser along metal masks with 0-8 orientation teeth/notches. Horizontal/vertical graft diameters ranged from 7.0/6.0 to 8.0/7.0 mm, and 12 to 24 interrupted sutures were used. Simultaneously, 11 eyes (26.2%) underwent cataract surgery, 3 (7.1%) underwent intraocular lens (IOL) exchange, and 1 (2.4%) underwent secondary IOL implantation. The main outcome measures included intraoperative complications, immune reactions, and final astigmatism/visual acuity at the end of follow-up. RESULTS: During surgery, 4 (9.5%) recipients had iris bleedings, and 10 (23.8%) ring-shaped superficial corneal thermal donor damages were detected. One (2.4%) immunologic graft rejection was seen in Fuchs dystrophy, and 3 (7.1%) in corneal ulcers occurred during follow-up (4.7 +/- 3.2 years). At the end of follow-up, corrected visual acuity (0.1/0.4; P < 0.001) and keratometric astigmatism (2.3 D/4.7 D, P = 0.001) increased significantly. CONCLUSIONS: In EELPK, intraoperative disadvantages, such as the need for interrupted sutures and a tendency toward higher and more irregular astigmatism, may be expected. This study does not have the power to statistically confirm the tendency of EELPK toward a lower rate of immunologic graft rejections after normal-risk keratoplasty. However, EELPK may have advantages in deep or perforated elliptically shaped corneal ulcers (such as in acanthamoeba keratitis).

Intra-individual variability of penetrating keratoplasty outcome after excimer laser versus motorized corneal trephination.

PURPOSE: To assess the intra-individual variability of outcomes after penetrating keratoplasty by comparing mechanical and nonmechanical corneal trephination. METHODS: Fifteen patients (30 eyes, 16 with keratoconus and 14 with Fuchs' dystrophy; median age at penetrating keratoplasty 56.3/53.5 years) were assessed whose trephination was performed using a motor trephine in one eye and the 193-nm excimer laser (MEL 60, Carl Zeiss-Meditec) in the other eye by one experienced surgeon. Subjective refractometry, standard keratometry, and corneal topography were used to assess best spectacle-corrected visual acuity (BSCVA); spherical equivalent refraction; keratometric and topographic central corneal power; refractive, keratometric, and topographic astigmatism; surface regularity index; surface asymmetry index; and potential visual acuity preoperatively, before first suture removal (at 1 year), and at last available follow-up after final suture removal but before additional surgery (1.3 and 1.9 years, respectively). RESULTS: Before first suture removal BSCVA was significantly higher (0.7 vs 0.5; P=.008) after excimer laser trephination. At the end of follow-up, refractive/ keratometric/topographic astigmatism (2.20/2.10/2.40 diopters [D] vs 5.00/6.00/7.10 D) and surface regularity index (0.8 vs 1.1) were significantly lower (P=.02, P=.005, P=.01, and P=.03, respectively) and potential visual acuity was significantly higher (0.9/0.6; P=.02) after excimer laser trephination. CONCLUSIONS: During long-term follow-up, all-sutures-out postkeratoplasty astigmatism and surface regularity are superior in the eye where nonmechanical excimer laser was applied in contrast to the fellow eye with motor trephination in the same individual.

Promising results using the Hanna Corneal Trephine System in penetrating keratoplasty.

PURPOSE: To evaluate the outcome of penetrating keratoplasties using the Hanna Corneal Trephine System. METHODS: Fifty-five patients out of 70, who had penetrating keratoplasty performed by a single surgeon (KHO), from 1995 to 2001, were reviewed in 2002, at Department of Ophthalmology, Hospital of Hilleroed, Denmark. The reviews were performed by a single observer (NJ). All donor corneas were trephined from the epithelial side. Visual acuity, refraction, corneal astigmatism, and graft survival were main outcome measures. RESULTS: Seventy-two percent of the patients achieved a visual acuity > or =0.5. In major subgroups, that is, Fuchs endothelial dystrophy, secondary endothelial dystrophy, and keratoconus, a best corrected visual acuity of > or =0.5 was achieved in 57, 67, and 100%, respectively. The mean (+/-SD) postoperative spherical refraction was +0.84 D (+/-3.72), whereas mean keratometric and refractive astigmatism were -3.24 D (+/-1.51) and -3.06 D (+/-1.95), respectively. The overall graft survival rate was 96.7% after 2 years and 81.2% after 5 years. At least 90% of all patients were content with the result and course of the operation. CONCLUSIONS: The best corrected visual acuity was better, and the degree of astigmatism was less compared to previously reported studies. We suggest that these findings can be partly explained by the operative technique, that is, cutting the donor and the recipient cornea from the epithelial side by the use of an artificial chamber.

[Evaluation of dynamic contour tonometry in penetrating keratoplasties]. / Evaluierung der dynamischen Konturtonometrie nach penetrierender Keratoplastik.

PURPOSE: The PASCAL dynamic contour tonometer (DCT) adapted to the corneal geometry is a new approach for digital measurement of intraocular pressure (IOP). The purpose of this study was to evaluate the DCT vs Goldmann applanation tonometry (GAT) in penetrating keratoplasties. METHOD: We included 92 consecutive eyes after penetrating keratoplasty (57 without sutures, 32 with 2 running sutures, 3 with 1 running suture) in this prospective cross-sectional study. The mean outcome measurements were central corneal power (Zeiss ophthalmometer) and central corneal thickness (ultrasound pachymetry Tomey AL-1000). IOP was evaluated in consecutive measurements including 3x DCT and 1x GAT. RESULTS: The mean IOP measured with DCT was 18.3+/-4.0 mmHg in contrast to GAT with 14.3+/-4.1 mmHg (p<0.001). Both methods showed a strong correlation of IOP values (r=0.74, p<0.001). The quality of measurement in keratoplasties after complete suture removal was between Q1 and Q3 in 88% with DCT in contrast to 59% with two running sutures. Three values with a reproducibility of 0.97 (Cronbach's alpha) could be obtained in 53 eyes without sutures and with a reproducibility of 0.94 (Cronbach's alpha) in 20 eyes (62.5%) with 2 running sutures. DCT or GAT did not correlate with central corneal thickness. The mean astigmatism did not differ between keratoplasties without sutures (4.86+/-3.35 D) or with two running sutures (4.2+/-2.8 D, p=0.38). CONCLUSIONS: The DCT provides reproducible IOP measurements in penetrating keratoplasties with significantly higher values in comparison to GAT. Nevertheless, as known for GAT, postoperative intrastromal corneal sutures after penetrating keratoplasty disturb the exact DCT measurement as well.

[MALKS: specifications and development]. / MALKS: especificações e desenvolvimento.

PURPOSE: To describe the characteristics of a new artificial anterior chamber (MALKS, Loktal, São Paulo, Brazil). METHODS: Characteristics analysis and description of a new artificial anterior chamber MALKS (Micro automated lamellar keratoplasty system). RESULTS: MALKS is composed of eight parts: a) artificial chamber; b) cornea's fix ring; c) nut to join the cornea's fix ring; d) rail and adjuster of lamellar diameter; e) flatteners, to pre-determine lamellar diameter; f) infusion system, that allows the digital objective peroperative control of the intracameral pressure; g) automated microkeratome, and h) marker. CONCLUSION: MALKS uses the same automated microkeratome developed for LASIK, can allow corneal lamella obtention with predetermined thickness and diameter, as well as the digital objective peroperative control of the intracameral pressure. This new artificial anterior chamber can be an important tool for superficial and endothelial keratoplasty.

[Evaluation of performance, efficacy and safety of semi-automated lamellar keratoplasty]. / Avaliação da exeqüibilidade, eficácia e segurança do transplante lamelar semi-automatizado de córnea.

PURPOSE: To evaluate the feasibility, efficacy and safety of a manual microkeratome and an artificial anterior chamber for lamellar keratoplasty (ALTK system). METHODS: Twenty-one eyes with superficial corneal opacities were submitted to semi-automated lamellar keratectomy. In recipient eyes keratectomy was performed as in refractive surgery. The donor flap was removed from the preserved corneal shell using the same microkeratome and an artificial anterior chamber. Lamella thickness was measured through ultrasound biomicroscopy (UBM) after surgery. RESULTS: The surgeries were accomplished successfully in 19 eyes. 80% of the flaps obtained in donated corneas and 84.2% of the flaps in recipient eyes had an up to 0.5 mm variation variation of the desired diameter. A high similarity in flap thickness between the donor flap and the recipient cornea was obtained. Postoperative visual acuity of 20/40 or better was observed in 52.6% of the eyes. Complications such as undesired diameter of the flap, a case of perforation in the recipient eye and a case of cornea ectasia were observed. CONCLUSION: The semi-automated lamellar keratoplasty ALTK system showed to be feasible due to the predictability and reproducibility regarding lamella thickness and diameter, efficient in the improvement of postoperative visual acuity and safe due to the low level surgical complication.

Anterior Synechiolysis with Healon Needle and Ophthalmic Viscosurgical Devices after Anterior Lamellar Dissection in Penetrating Keratoplasty.

PURPOSE: We described a technique to perform anterior synechiolysis with a healon needle and Viscoat® ophthalmic viscosurgical devices (OVDs) through anterior lamellar dissection in penetrating keratoplasty. METHODS: OVDs were gently injected between iridocorneal adhesions with a healon needle to make a blunt dissection after anterior lamellar corneal dissection. Anterior synechiolysis at 360 degrees was completed with a healon needle and OVDs. Subsequently, the deep corneal lamella was cut with right and left Troutman-Katzin corneal scissors. 24 interrupted sutures were made with 10-0 nylon suture to implant the donor cornea. RESULTS: In two eyes from two patients, with corneal opacity and nearly total anterior synechiae, clear grafts and relatively deep anterior chambers were achieved. Penetrating keratoplasty with anterior synechiolysis was thus successful with a healon needle and OVDs through lamellar dissection. CONCLUSIONS: Anterior synechiolysis with a healon needle and OVDs through lamellar dissection is a safe and efficient technique for keratoplasty in patients with corneal opacity with anterior synechiae.