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 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.

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.

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.

A new technology for applanation free corneal trephination: the picosecond infrared laser (PIRL).

The impact of using a Femtosecond laser on final functional results of penetrating keratoplasty is low. The corneal incisions presented here result from laser ablations with ultrafast desorption by impulsive vibrational excitation (DIVE). The results of the current study are based on the first proof-of-principle experiments using a mobile, newly introduced picosecond infrared laser system, and indicate that wavelengths in the mid-infrared range centered at 3 µm are efficient for obtaining applanation-free deep cuts on porcine corneas.

Novel spatula and dissector for safer deep anterior lamellar keratoplasty / Uso de espátula e dissector para otimização da ceratoplastia lamelar anterior profunda (DALK)

Objective: We describe a novel spatula and dissector to facilitate the big-bubble technique in deep anterior lamellar keratoplasty (DALK). Methods: A 29-year-old man who was diagnosed with bilateral keratoconus underwent deep anterior lamellar keratoplasty (DALK). After 350μm partial thickness incision of the recipient cornea, the Bonfadini dissector was inserted at the deepest point in the peripheral incision and could be advanced to the center of the cornea safely because of its "semi-sharp" tip. After achieving the big-bubble (BB) separation of Descemet membrane (DM) from the overlying stroma, the anterior stromal disc was removed. Viscoelastic material was placed on the stromal bed to prevent uncontrolled collapse and perforation of DM during the paracentesis blade incision into the BB. We could detect the safe opening of the BB using the Bonfadini dissector by the leakage of air bubbles into the viscoelastic material. After injecting viscoelastic material into the BB space, we inserted the Bonfadini spatula into the bigbubble safely because of its curved profile and blunt edges. The groove along the length of the Bonfadini spatula enables safe and efficient incision or the residual stromal tissue using the pointed end of a sharp blade while protecting the underlying DM. After removal of posterior stroma, the donor button was sutured with 16 interrupted 10-0 nylon sutures. Results: This technique and the use of the Bonfadini spatula and dissector facilitate exposure of Descemet membrane. Conclusion: The smooth Bonfadini DALK spatula and dissector facilitate safe and efficient completion of DALK surgery. .

Objetivo: Descrevemos o uso de novos instrumentais cirúrgicos para facilitar a técnica de "big-bubble" na ceratoplastia lamelar anterior profunda (DALK). Métodos: Paciente masculino, 29 anos, foi diagnosticado com ceratocone bilateral e submetido à ceratoplastia lamelar anterior profunda (DALK). Após incisão da córnea receptora numa profundidade de 350μm de espessura parcial, o dissector Bonfadini foi inserido no ponto mais profundo da incisão periférica e pode avançar para o centro da córnea com segurança devido à sua ponta semiafiada. Depois de realizar a "big-bubble" (BB) e atingir a separação da Membrana de Descemet (MD) do estroma sobrejacente, o disco corneano de estroma anterior foi removido. Um viscoelástico foi colocado sobre o leito do estroma remanescente para impedir o colapso não-controlado e perfuração da MD durante a incisão na BB com lâmina de paracentese. Verificamos segurança no rompimento do estroma remanescente com o auxílio do dissector Bonfadini, para liberação da bolha de ar da BB através do viscoelástico. Depois de injetar o viscoelástico no espaço da BB, inserimos a espátula Bonfadini neste espaço, o que demonstrou-se seguro devido ao formato curvo e das bordas arredondadas do instrumental. A chanfradura ao longo do comprimento da espátula Bonfadini permite a incisão pela ponta de uma lâmina afiada, protegendo assim a MD subjacente. Após a remoção do estroma posterior, o botão doador foi suturado com 16 pontos interrompidos de fio nylon 10.0. Resultados: Esta técnica e o uso da espátula Bonfadini e dissector facilitam a exposição de membrana de Descemet. Conclusão: A superfície lisa da espátula Bonfadini e dissector, facilitam a realização segura e eficiente da ceratoplastia lamelar anterior profunda (DALK). .

[Perspectives of laser-assisted keratoplasty: current overview and first preliminary results with the picosecond infrared laser (λ = 3 µm)]. / Perspektiven der laserassistierten Keratoplastik: Eine aktuelle Übersicht und erste experimentelle Erfahrungen mit dem Pikosekundeninfrarotlaser (λ = 3 µm).

BACKGROUND: This article provides a review of the current state of laser-assisted keratoplasty and describes a first proof of concept study to test the feasibility of a new mid-infrared (MIR) picosecond laser to perform applanation-free corneal trephination. METHODS: The procedure is based on a specially adapted laser system (PIRL-HP2-1064 OPA-3000, Attodyne, Canada) which works with a wavelength of 3,000 ± 90 nm, a pulse duration of 300 ps and a repetition rate of 1 kHz. The picosecond infrared laser (PIRL) beam is delivered to the sample by a custom-made optics system with an implemented scanning mechanism. Corneal specimens were mounted on an artificial anterior chamber and subsequent trephination was performed with the PIRL under stable intraocular pressure conditions. RESULTS: A defined corneal ablation pattern, e.g. circular, linear, rectangular or disc-shaped, can be selected and its specific dimensions are defined by the user. Circular and linear ablation patterns were employed for the incisions in this study. Linear and circular penetrating PIRL incisions were examined by macroscopic inspection, histology, confocal microscopy and environmental scanning electron microscopy (ESEM) for characterization of the incisional quality. Using PIRL reproducible and stable incisions could be made in human and porcine corneal samples with minimal damage to the surrounding tissue. CONCLUSION: The PIRL laser radiation in the mid-infrared spectrum with a wavelength of 3 µm is exactly tuned to one of the dominant vibrational excitation bands of the water molecule, serves as an effective tool for applanation-free corneal incision and might broaden the armamentarium of corneal transplant surgery.

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.

[Visual acuity and astigmatism after keratoplasty. Differences between the guided trephine system and motor trephine]. / Visus und Astigmatismus nach Keratoplastik. Unterschiede zwischen geführtem Trepansystem und Motortrepan.

BACKGROUND: The purpose of this study was to assess the differences in postoperative visual acuity, astigmatism, and selected postoperative complications between a guided trephine system (GTS) and motor trephine after penetrating keratoplasty. PATIENTS AND METHODS: In this retrospective analysis 74 patients who had undergone penetrating keratoplasty either by GTS (n = 53) or by motor trephine (Motortrepan) (n = 21) were included. Both patient groups included in this analysis were selected to ensure a homogeneous distribution of preoperative parameters to the greatest possible extent. However, some significant differences in patient selection between the two groups could not be avoided. Patients in the motor trephine group were older (mean age 68.4 years vs 56.4 years; p < 0.01) and had Fuchs' endothelial dystrophy more often (47.6 % vs 26.4 %) and significantly less keratoconus (14.3 % vs 32.1 %). RESULTS: No significant differences regarding visual acuity outcomes could be found between GTS and Motortrepan. In both patient groups there were no differences in the amount of preoperative astigmatism (1.36 vs. 2.0 dpt., p = 0.39). However, at the time of final corneal suture removal (2.23 vs. 3.5 dpt., p = 0.03) and at a postoperative control 1 year after final suture removal (2.29 vs. 3.85 dpt., p = 0.005) the amount of astigmatism in the motor trephine group was found to be significantly higher. CONCLUSION: In summary penetrating kerastoplasty using the motor trephine was found to result in significantly higher postoperative astigmatism than those performed with the GTS.

[Results with the Boston keratoprosthesis]. / Ergebnisse nach Boston-Keratoprothese.

BACKGROUND: The Boston keratoprosthesis (BKP) is a surgical therapeutic option in patients with corneal disease and poor prognosis for penetrating keratoplasty. The purpose of this study was to summarize our results with this surgical technique which we have employed at our institution since November 2009. METHODS: All patients who underwent the BKP procedure at our institution between November 2009 and August 2011 were identified retrospectively and the data were analyzed. The surgical procedure and postoperative treatment were performed following the recommendations of the developers of the BKP. RESULTS: A total of 14 patients were included in the study and the patient age ranged from 36 to 78 years. All patients had superficial and stromal corneal opacification with loss of the normal corneal surface (conjunctivalization). In 13 patients the BKP was implanted after at least 1 penetrating keratoplasty (including 3 matched grafts) and in 1 patient it was performed as a primary procedure. The underlying diseases were Stevens-Johnson syndrome, chemical injury, chronic atopic dermatitis in neurodermitis, keratoconus, granulomatous uveitis, congenital glaucoma and eyeball injury/burn. The follow-up ranged from 1 to 21 months. Postoperative complications consisted of prolonged inflammatory anterior chamber reaction with synechia, deposits on the intraocular lens, posterior capsule opacification, secondary glaucoma, hypotension, conjunctival growth over the keratoprosthesis and cystoid macular edema. All cases had overall improvement of visual acuity at the last follow-up visit. The maximum improvement was from counting fingers to 0.7. CONCLUSION: Until now all BKPs have been preserved. At our institution the BKP is becoming increasingly more important even in such cases with a (very) poor prognosis for matched limbal and/or corneal grafts. Reimbursement for the BKP must, however be organized on a case by case basis.

[Perspectives of femtosecond laser-assisted keratoplasty]. / Perspektiven der Femtosekundenlaser-assistierten Keratoplastik.

The femtosecond laser technique allows completely new trephination procedures in penetrating and lamellar keratoplasty. With femtosecond laser-assisted penetrating keratoplasty it is possible to perform profiled trephination, such as top hat and mushroom profiles. Thus, it is easier to get a watertight wound closure intraoperatively and due to the larger wound surface wound healing is faster and allows early complete suture removal. In lamellar keratoplasty the femtosecond laser enables the surgeon to cut to any depth in the corneas resulting in thin corneal donor buttons, e.g. for DSAEK. In this manuscript an overview is given of the state of the art and of the perspectives of femtosecond laser keratoplasty.

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.

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.

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).

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

OBJETIVO: Avaliar a exeqüibilidade, eficácia e segurança do uso de microcerátomo e câmara anterior artificial para o transplante lamelar (sistema ALTK®). MÉTODOS: 21 olhos com opacidades corneanas superficiais foram submetidos ao transplante lamelar semi-automatizado de córnea. Nos olhos receptores a ceratectomia foi realizada de modo semelhante a uma cirurgia refrativa. As lamelas doadoras foram obtidas a partir de botões esclero-corneanos utilizando o mesmo microcerátomo e uma câmara anterior artificial. As medidas das espessuras corneanas foram feitas através da biomicroscopia ultra-sônica. RESULTADOS: As cirurgias obtiveram êxito em 19 olhos. Em 80 por cento das lamelas obtidas em córneas doadoras e em 84,2 por cento das lamelas em olhos receptores houve uma variação de até 0,5 mm do diâmetro desejado. Verificou-se alta semelhança entre as espessuras das lamelas obtidas nos olhos receptores e lamelas doadoras. Obteve-se acuidade visual corrigida pós-operatória igual ou superior a 20/40 em 52,6 por cento dos olhos. Foram observadas complicações como diâmetro inadequado da lamela, perfuração intra-operatória no olho receptor e ectasia corneana pós-operatória (um caso). CONCLUSÕES: O transplante lamelar semi-automatizado de córnea mostrou-se exequível pela reprodutibilidade das espessuras e diâmetros das lamelas; eficaz pela melhora da acuidade visual pós-operatória e seguro, devido ao baixo índice de complicações cirúrgicas.

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 percent of the flaps obtained in donated corneas and 84.2 percent 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 percent 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.

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.