Project description:In penetrating keratoplasty (PKP), the proper corneal suture placement is very important for successful transplantation and restoring functional vision. Generating sutures with accurate depth is difficult for the surgeon because of the tissue's softness, lack of depth information, and hand tremors. In this paper, an automatic cornea grasping device is proposed, which detects when the device reaches the target suture depth. When the device reaches the target depth, the device rapidly grasps the cornea to prevent error induced by human hand tremors. In the paper, the performance of the proposed sensor, the actuator, and the device are experimentally verified with ex vivo experiment. The result showed that the proposed device could enhance the accuracy and precision of the corneal suture depth.
Project description:PurposeTo present the clinical outcome of mitomycin intravascular chemoembolization (MICE) as a prophylactic treatment in a patient with HSV-induced corneal neovascularization (NV) before penetrating keratoplasty (PKP).ObservationsA 53-year-old male patient presented with a medical history of recurrent herpes simplex virus (HSV) corneal infection. The patient reported worsening visual acuity despite maintenance treatment with systemic antivirals and topical corticosteroids. After the appearance of corneal NV, subconjunctival triamcinolone and bevacizumab injections were given with limited and temporary improvement. Due to worsening corneal NV, MICE was subsequently performed, resulting in the elimination of corneal NV from the visual axis, which allowed for successful PKP 4 months later. Cataract surgery was performed 6 months after PKP.Conclusions and importanceThis report describes the potential efficacy of MICE as a prophylactic treatment for corneal NV prior to PKP.
Project description:The aim of this study was to assess the effect of donor and recipient factors on corneal allograft rejection and evaluate whether a rejection event was associated with graft failure.One thousand ninety subjects undergoing penetrating keratoplasty for a moderate risk condition (principally Fuchs dystrophy or pseudophakic corneal edema) were followed for up to 12 years. Associations of baseline recipient and donor factors with the occurrence of a rejection event were assessed in univariate and multivariate proportional hazards models.Among 651 eyes with a surviving graft at 5 years, the 10-year graft failure (±99% confidence interval) rates were 12% ± 4% among eyes with no rejection events in the first 5 years, 17% ± 12% in eyes with at least 1 probable, but no definite rejection event, and 22% ± 20% in eyes with at least 1 definite rejection event. The only baseline factor significantly associated with a higher risk of definite graft rejection was a preoperative history of glaucoma, particularly when previous glaucoma surgery had been performed and glaucoma medications were being used at the time of transplant (10-year incidence 35% ± 23% compared with 14% ± 4% in eyes with no history of glaucoma/intraocular pressure treatment, P = 0.008).Patients who experienced a definite rejection event frequently developed graft failure raising important questions as to how we might change acute and long-term corneal graft management. Multivariate analysis indicated that previous use of glaucoma medications and glaucoma filtering surgery was a significant risk factor related to a definite rejection event.
Project description:Fungal keratitis is an infection that is insidious and frequently misdiagnosed. Those with chronic eye surface conditions, contact lenses, systemic immunosuppression, and diabetes have been the most frequently affected with fungal keratitis. An 84-year-old male patient with a history of bilateral penetrating keratoplasty (PK) for keratoconus presented with pain and decreased visual acuity on his left eye. A corneal perforation was found, which was treated immediately with a full-thickness corneal transplant. The specimen was sent for bacterial and fungal cultures. Topical corticosteroids were prescribed postoperatively. Beauveria bassiana was isolated from the corneal scrapings. The postoperative treatment was modified by reducing the dose of corticosteroid and adding topical natamycin together with systemic posaconazole. No recurrence occurred in the transplant four months postoperatively under topical dexamethasone 0.1% b.i.d. This is the first case of keratitis and perforation in a previously transplanted cornea. Due to the rarity of the infection, there are no clear guidelines for postoperative prophylaxis in B. bassiana infection. Either the continuation of corticosteroids or the switch to another immunosuppressive therapy and selecting the appropriate antifungal regimen posed a significant therapeutic dilemma.
Project description:ObjectiveThis study sought to compare graft survival, graft rejection and the visual acuity outcome of endothelial keratoplasty (EK) with repeat penetrating keratoplasty (PK) after failed PK.MethodsA systematic literature search with subsequent screening of the identified articles was conducted to obtain potentially eligible randomized clinical trials (RCTs) and comparative cohort studies. To assess the methodological quality of the included studies, the Jadad Scale or Newcastle-Ottawa Scale (NOS) was used based on the study design. To calculate the pooled odds ratios (ORs) for graft survival, graft rejection and the visual acuity outcome with 95% confidential intervals (CIs), a fixed- or random-effects model was applied based on the heterogeneity across studies.ResultsFour comparative cohort studies (n = 649 eyes) comparing the outcome of EK with repeat PK after failed PK were included in this review. These studies were considered high quality, with NOS scores ranging from 6 to 9. The EK group showed a significantly lower risk of graft rejection than the repeat PK group [0.43 (95% CI: 0.23-0.80, P = 0.007)]. In addition, no significant differences were observed in a comparison of graft survival and visual acuity (P values ranged from 0.81 to 0.97 using the Der-Simonian and Laird random-effects model).ConclusionsAs an alternative to repeat PK, EK after failed PK allows for potential reduction of the risk of graft rejection; however, it does not appear to confer a significant advantage in graft survival or visual acuity.
Project description:Background. To evaluate the change in corneal astigmatism after intrastromal corneal ring segment (ICRS) implantation in keratoconus patients with previous deep anterior lamellar keratoplasty (DALK). Design was a longitudinal, retrospective, interventional study. The study included 25 eyes of 24 patients with keratoconus who had DALK performed at least two years prior to ICRS implantation. All patients had a clear corneal graft with up to 8.00 D of corneal astigmatism and intolerance to contact lenses. The studied parameters were age, sex, corrected distance visual acuity (CDVA), maximum keratometry (K1), minimum keratometry (K2), spherical equivalent, and astigmatism. There was a statistically significant decrease in the postintervention analysis as follows: 3.5 D reduction in K1 (p < 0.001); 1.53 D in K2 (p = 0.005); and 2.52 D (p < 0.001) in the average K. The spherical equivalent reduced from -3.67 D (±2.74) to -0.71 D (±2.35) (p < 0.001). The topographic astigmatism reduced from 3.87 D preoperatively to 1.90 D postoperatively (p < 0.001). The CDVA improved from 0.33 (±0.10) to 0.20 (±0.09, p < 0.001). ICRS implantation is a useful option for the correction of astigmatism after DALK as it yields significant visual, topographic, and refractive results.
Project description:To investigate the incidence, causes, occurrence time, and range of wound and outcomes of wound dehiscence in patients treated by penetrating keratoplasty (PK) or lamellar keratoplasty (LK).We retrospectively reviewed medical records of keratoplasty in Shandong Eye Hospital from January 2006 to June 2017. Thirty-one eyes of 30 patients had sustained wound dehiscence (WD) after surgical treatment. The surgical type, causes, occurrence time, extent of the wound, treatment, and outcomes were recorded.The study population consisted of 26 men and 4 women. The mean age at the occurrence of WD was 44.6 years old (range: 12-78 years), and the mean time from keratoplasty to WD was 45.9 months (range: 1-204 months). WD occurred in 23 eyes (23/1385, 1.66%) after PK and 8 eyes (8/1632, 0.49%) after LK (p < 0.05). Twenty-seven eyes (27/31, 87.0%) had trauma-induced dehiscence. The mean range of dehiscence was 5.5 o'clock. The vision ranged from 20/50 to light perception after wound suture. The eyes receiving LK had fewer serious complications than PK.Compared with LK, PK seems to be more prone to result in wound dehiscence. The WD after LK may be less severe. The visual acuity after treatment of WD can be worse in the eyes with PK than LK.
Project description:A 68-year-old man who had undergone two penetrating keratoplasties of his left eye was admitted with early corneal graft failure. Culture of the anterior chamber fluid yielded Paracoccus yeei, a nonfermentative gram-negative bacillus which thus far had only been implicated in ocular disease by means of PCR and 16S rRNA gene sequencing directly on patient material.
Project description:PurposeThis study aims (1) to investigate the feasibility of robot-assisted penetrating keratoplasty (PK) using the new Da Vinci Xi Surgical System and (2) to report what we believe to be the first use of this system in experimental eye surgery.MethodsRobot-assisted PK procedures were performed on human corneal transplants using the Da Vinci Xi Surgical System. After an 8-mm corneal trephination, four interrupted sutures and one 10.0 monofilament running suture were made. For each procedure, duration and successful completion of the surgery as well as any unexpected events were assessed. The depth of the corneal sutures was checked postoperatively using spectral-domain optical coherence tomography (SD-OCT).ResultsRobot-assisted PK was successfully performed on 12 corneas. The Da Vinci Xi Surgical System provided the necessary dexterity to perform the different steps of surgery. The mean duration of the procedures was 43.4 ± 8.9 minutes (range: 28.5-61.1 minutes). There were no unexpected intraoperative events. SD-OCT confirmed that the sutures were placed at the appropriate depth.ConclusionsWe confirm the feasibility of robot-assisted PK with the new Da Vinci Surgical System and report the first use of the Xi model in experimental eye surgery. Operative time of robot-assisted PK surgery is now close to that of conventional manual surgery due to both improvement of the optical system and the presence of microsurgical instruments.Translational relevanceExperimentations will allow the advantages of robot-assisted microsurgery to be identified while underlining the improvements and innovations necessary for clinical use.