Outcome of primary adult optical penetrating keratoplasty with imported donor corneas

Purpose To evaluate the outcome of primary adult optical penetrating keratoplasty (PKP) performed with internationally acquired donor tissue. Patients and methods A retrospective review was performed of the medical records of every patient 12 years of age or older who underwent PKP for keratoconus, corneal edema, stromal scarring, or stromal dystrophy at King Khaled Eye Specialist Hospital in the Kingdom of Saudi Arabia between January 1, 1997 and December 31, 2001, and for whom a minimum of 3 months’ follow-up was available. Results Of 885 eyes that met the inclusion criteria, there were 453 eyes with keratoconus, 180 eyes with corneal edema, 171 eyes with stromal scarring, and 81 eyes with stromal dystrophy. For the entire group, the probability of graft survival was 96.9% at 1 year, 86.0% at 3 years, and 80.3% at 5 years. The 5-year probability of graft survival was 96.2% for keratoconus, 39.4% for corneal edema, 71.1% for stromal scarring, and 85.2% for stromal dystrophy. Increasing donor age was significantly associated with an increased risk of graft failure on multivariate Cox proportional hazard regression analysis (P = 0.005). Endothelial cell density, death-to-preservation time, and preservation-to-surgery time were not significantly associated with an increased risk of graft failure. Conclusions In our patient population, excellent graft survival was achieved utilizing internationally acquired donor tissue for eyes with keratoconus, stromal dystrophy, and stromal scarring, but not for those with corneal edema.     

Ocular refraction after penetrating keratoplasty with infant donor corneas

Five adult patients underwent penetrating keratoplasty in which corneal tissue from donors 3 months old or younger was used. In each case, a large myopic shift in refraction was found after surgery (mean, 9 diopters). The average postoperative spherical equivalent was -7.35 diopters. This resulted from the extremely steep curvature of the infant donor cornea (mean keratometric value, 57.67 diopters). The induced anisometropia and steep corneal topography of the infant donor cornea prevented visual rehabilitation with spectacles or contact lenses in four of five patients. Our findings suggested that corneal tissue from donors 3 months old or younger may be unsuitable for penetrating keratoplasty in emmetropic adults or anisometropic patients undergoing surgery in the more myopic eye.     

不同种族角膜植片对穿透性角膜移植术效果的影响

目的 通过观察不同种族间穿透性角膜移植手术的效果,总结不同种族之间穿透性角膜移植的可行性。设计 回顾性病例系列。研究对象 北京同仁眼科中心2002年10月至2003年3月因角膜白斑、角膜内皮失代偿、角膜移植术后植片失败等接受穿透性角膜移植术患者10例（10眼）。方法 采用国际组织库提供的中期保存角膜植片进行穿透性角膜移植术,其中高加索人种角膜8片,西班牙人种1片,非洲人种1片。术前收集患者资料,术后进行随访和临床观察,评价角膜植片的存活情况以及疗效。主要指标 视力,角膜植片透明度,角膜新生血管分级。结果 10例患者平均随访（12.6±3.86）个月,4例患者角膜植片基本保持透明,视力平均提高1~2行。6例（60%）患者出现植片混浊、植片水肿、新生血管长入等排斥反应,视力不提高。结论 本文小样本观察显示不同种族角膜供体可以用于穿透性角膜移植治疗。（眼科, 2013, 22:98-100）     

Therapeutic penetrating keratoplasty in severe fungal keratitis using cryopreserved donor corneas

AIMS: To investigate whether cryopreserved donor cornea could be used for therapeutic penetrating keratoplasty (PKP) to eradicate the infection, obviate complications, and preserve anatomical integrity in severe fungal keratitis. METHODS: In this retrospective, consecutive case series, 45 eyes of 45 patients with severe fungal keratitis, which exhibited anterior chamber collapse, corneal perforation, and/or large suppurative corneal infiltrate, received therapeutic PKP after removal of the infected corneal tissue, irrigation of the anterior chamber by 0.2% fluconazole solution, iris dissection of fibrinoid membrane, and iridectomy and therapeutic PKP using corneas cryopreserved at -20 degrees C. RESULTS: Among 45 eyes, 39 eyes (86.7%) were successfully eradicated the fungal infection without recurrence and maintained their anatomical integrity without any complication. Four of 45 eyes (8.9%) showed postoperative rise of intraocular pressure, of which three were controlled with subsequent antiglaucoma surgeries, whereas one eye needed additional antiglaucoma medications. Two of 45 eyes (4.4%) were enucleated because of uncontrollable fungal infection and secondary retinal detachment, respectively. 23 eyes received subsequent optical PKP and, among them, 21 maintained clear corneal grafts and two suffered from graft failure due to allograft rejections. CONCLUSION: Cryopreserved donor corneas are effective substitutes in therapeutic PKP to control severe fungal corneal infection and preserve the global integrity, and may offer additional advantages over conventional PKP in reducing allograft rejection, eradicating fungal infection during the postoperative period, and improving the success of optical PKP for visual rehabilitation.     

Frequency of positive donor rim cultures after penetrating keratoplasty using hypothermic and organ-cultured donor corneas

PURPOSE: To compare the frequency of positive rim cultures after penetrating keratoplasty using corneas preserved by hypothermic and organ culture storage. To evaluate the influence of standard procurement techniques on the frequency of microbial donor rim contamination. METHODS: Six hundred four donor corneas stored at 31 degrees C and 214 at 4 degrees C were studied. Microbiology studies were carried out during organ culture storage, and corneas with positive medium cultures were discarded. Frequency of postoperative positive rim cultures was related to the type of corneal storage and procurement technique used. RESULTS: Thirty-nine (6.4%) corneas with positive medium cultures were discarded during organ culture. Microbiology reports of 628 donor rims cultures from 671 (94%) consecutive transplants were reviewed. Positive rim cultures resulted in 24 (3.8%) cases. None of the patients developed endophthalmitis. The frequency of postoperative positive rim cultures was greater after hypothermic than organ culture storage, being 9.8% and 1.3%, respectively (chi(2) = 24.9; P < 0.001). With organ culture storage, the frequency of positive rim cultures was 1.3% and 1.4% after enucleation and in situ corneal excision, respectively (chi(2) = 0.03; P = 0.638). After hypothermic storage, positive rim cultures were found in 8% of the corneas procured using enucleation and 12% of the corneas excised in situ (chi(2) = 0.829; P = 0.254). CONCLUSIONS: Organ culture storage allows one to recognize and discard corneas with microbial contamination during storage. This method significantly reduces the frequency of postoperative positive rim cultures compared with hypothermic storage. Procurement methods do not influence the percentage of positive rim cultures.     

Storage of donor corneas, surgery, outcome, and complications of penetrating keratoplasty

A review of current literature reveals continuing concerns regarding the safety and success of penetrating keratoplasty. Quality assurance within eyebanks is directed inter alia at the prevention of transmission of infection from donor to host. Recent controversy in the United Kingdom regarding the transmission of Creutzfeldt-Jakob disease underscores the need for constant vigilance and regular review of eyebank standards. The improvement of the success rates for keratoplasty in difficult cases and the elimination or reduction of side effects assume increasing importance as the technical difficulties in more straightforward cases are solved. This review discusses some recent publications in this field.     

Results of penetrating keratoplasty in vascularized corneas.

A retrospective longitudinal study of 105 penetrating keratoplasties for vascularized corneal opacities was done. The results of cases with an etiology of healed trachoma or healed corneal ulcers were compared. The vascularization was graded from Grade I to V depending on the quadrant and type of vascularization. Graft clarity of 2+ or more in cases of trachomatous opacity was achieved in 93% of cases and that after postinfectious opacity in 71.8%. Prognosis was poor in cases where deep vascularization was present in more than two quadrants or more than 180 degrees.     

Outcomes of combined penetrating keratoplasty and cataract extraction compared with penetrating keratoplasty alone

PURPOSE: To compare the rejection rates, graft failure rates, mean visual, keratometric and refractive outcomes of combined penetrating keratoplasty and cataract extraction with penetrating keratoplasty alone. METHODS: A retrospective study of all patients who had combined keratoplasty and cataract extraction/intraocular lens insertion (49 eyes; mean age 65.3 years; mean follow up 17 months) compared with all patients who had keratoplasty only (58 eyes; mean age 64.0 years; mean follow up 14 months). RESULTS: One hundred and seven eyes in 99 patients had keratoplasty in the period and were included in the study. The most common indication for keratoplasty in patients who had triple procedures was Fuchs' endothelial dystrophy (24.5%). During the study seven (6.5%) grafts failed and four (3.7%) had allogenic rejection without failure during this period. There was no statistical difference between the graft survival rates of the two study groups. The mean postoperative logMAR visual acuity (VA) was 0.42 and postoperative VA of 6/12 or better was seen in 71% of patients. Mean postoperative corneal curvature was 44.6 dioptres (D), mean corneal astigmatism was -4.0 D and was >or=5 D in 38%. Mean double-angle Cartesian coordinates for corneal astigmatism were x-0.87 D and y-0.29 D. Mean best sphere of postoperative refractions was -0.61 D and mean absolute refractive error was 2.2 D. There was no statistically significant difference in VA, keratometric or refractive outcome measures between the two study groups. CONCLUSION: Over a short follow up, keratoplasty combined with cataract extraction/intraocular lens insertion showed a similar risk of graft failure or allogenic graft rejection when compared with keratoplasty alone and we recommend the triple procedure for quicker visual recovery and less operative procedures.     

Eosinophils in corneas removed by penetrating keratoplasty.

One hundred consecutively submitted corneas removed by penetrating keratoplasty were studied histologically to determine the frequency in which eosinophils are found. In 20 corneas eosinophils occurred in densities ranging from 0.2 to more than 50 per high power field (HPF), and accounted for 1.5% to 100% of the total leucocytes counted. More than half of the corneal specimens containing eosinophils, including six of seven corneas having the highest eosinophil concentrations, were failed grafts. Because the concentration of eosinophils was in many cases beyond that attributable to non-specific vascular permeability, the existence of eosinophil chemotaxic substances in the cornea is postulated.     

Outcomes of penetrating keratoplasty in keratoconus

PURPOSE: Keratoconus (KCN) is one of the most common indications of corneal transplantation in Iran. This study was conducted to determine the outcomes of penetrating keratoplasty (PK) for KCN in patients operated in a private practice setting from 1994 to 2001. METHODS: This longitudinal retrospective study included 164 eyes of 164 patients. Variables included preoperative keratometry, trephination and suturing techniques, donor-recipient disparity, surgical complications, immunologic rejection, graft clarity, postoperative spherical and cylindrical refractive error, keratometry, uncorrected and best spectacle-corrected visual acuity, suture management, and the results of keratorefractive procedures. RESULTS: Patients were followed for a mean period of 33.5 months. Mean postoperative best spectacle-corrected visual acuity (BSCVA) at last follow-up was 0.14 +/- 0.11 LogMAR (20/25); mean spherical error and mean corneal astigmatism were -0.61 +/- 2.6 and 3.4 +/- 1.8 D, respectively. Final visual outcomes were not significantly correlated with trephination and suturing techniques or severity of the ectasia. Although donor-recipient disparity did not affect final astigmatism, more myopic shift was observed with greater disparity, but this finding was not of statistical significance. Overall, 26.8% of the patients required keratorefractive surgery, which resulted in 2.9 D reduction in corneal astigmatism. Immunologic graft rejection occurred in 28% of cases; however, all episodes responded to medical management, and none resulted in graft failure. CONCLUSION: Penetrating keratoplasty is a safe and effective procedure with remarkable optical and visual outcomes for patients with keratoconus who are contact lens intolerant or have unacceptable corrected visual acuity. Neither severity of the disorder nor trephination and suturing techniques significantly affects final visual outcomes. Less graft-recipient disparity (0.25 versus 0.50 mm) seems to induce less myopic shift.     

Outcomes of femtosecond laser-assisted penetrating keratoplasty

PURPOSE: To evaluate outcomes from the use of a femtosecond laser to trephine both donor and recipient corneas during penetrating keratoplasty (PK). DESIGN: Prospective interventional case series. METHODS: Patients were recruited from the cornea clinic of the Singapore National Eye Centre. We used a 10-kHz Femtec (20/10 Perfect Vision, Heidelberg, Germany) femtosecond laser to perform trephination of the donor cornea on an artificial anterior chamber, followed by trephination of the recipient cornea. Trephination cuts were straight and performed 90 degrees to the corneal surface. Tissue bridges were bluntly separated with a Barrett phaco chopper. The donor button was then sutured to the recipient with double continuous sutures, or interrupted sutures if significant host corneal vascularization was present. Postoperatively, visual acuity, refraction, intraocular pressures, and optical coherence tomography (Visante; Carl Zeiss, Jena, Germany) were evaluated. RESULTS: Eight eyes of eight patients underwent PK for conditions ranging from bullous keratopathy to corneal scarring from herpetic stromal keratitis. Patients were followed up for a mean of 9.5 months. Best-corrected visual acuities of patients with no ocular comorbidity ranged from 20/20 to 20/80. Mean cylindrical refractive error at last review was 2.56 diopters [D] (range, 0.50 to 4.00 D). Tissue bridges were bluntly dissected except for one case that required scissors completion of trephination. No complications were encountered related to use of the Femtec laser. CONCLUSION: The Femtec laser reliably trephines both donor and recipient corneas for PK, with good visual outcomes and relatively low degrees of astigmatism.     

甘油长期冷冻保存兔角膜用于穿透性角膜移植效果观察

目的探索不同条件下甘油长期冷冻保存的角膜应用于穿透性角膜移植的可靠性和可行性。方法25只兔眼随机分为4个保存组和1个对照组，保存组按不同方法置于无水甘油中-25℃保存2月，最终全部行同种异体PKP术，术后以裂隙灯显微镜、A超以及锥蓝-茜素红活性染色等测得各组的植片透明率、厚度及角膜内皮细胞（CEC）存活率等指标并进行比较。结果术后各组植片均可见大量活性CEC存在，植片CEC与植床CEC分界清楚，形态不同。角膜片保存组术后的植片透明率、厚度以及CEC存活率均显著好于跟球保存组，角膜片内皮面添加透明质酸钠保存又优于角膜片直接保存。结论甘油冷冻保存法可以长期保存CEC活性，其中以角膜片内皮面添加透明质酸钠后保存最为可靠，这一改良方法可以满足穿透性角膜移植术的需要。     

A safer alternative approach to penetrating keratoplasty in opaque corneas

Background:This video demonstrates a useful technique of keratoplasty which can be routinely undertaken by all surgeons when imaging modalities such as anterior segment optical coherence tomography are not available and prior patient history is not forthcoming.Purpose:To demonstrate a technique of lamellar separation and layer by layer removal of host cornea when dealing with keratoplasty in perforated corneal ulcers, adherent leucomas, dense corneal opacities, which obscure visualization of the iris and anterior chamber details.Synopsis:In this video, we demonstrate penetrating keratoplasty in a failed opacified graft with iridocorneal adhesions, with no visualization of anterior chamber details. Lamellar dissection of the host cornea is done starting at its periphery and moving centrally, with gentle peeling of the superficial layers, the epithelium and bulk of stroma, following which, the deeper portion of the cornea is dissected and separated from underlying adherent iris tissue. Layer by layer separation allows better visualization through the remaining thin layers of the cornea. This permits fine dissection and layered removal of the cornea, thereby avoiding injury to iris and lens. Debulking of the host cornea decreases the force that is needed to be applied to separate adherent iris tissue from the host cornea, and reduces the chances of sudden entry into the anterior chamber and subsequent damage to the iris or lens. This also reduces the chance of iris tears, iridodialysis and bleeding from the iris and helps maintain iris integrity, which is essential intraoperatively for protection of lens and anterior chamber formation, and to avoid glare and photophobia postoperatively. Preventing iris damage also reduces the chances of formation of peripheral anterior synechiae (PAS), which can predispose to graft rejection, graft failure and secondary glaucoma.Highlights:Layer by layer corneal separation beginning inside the graft host junction, careful separation of iridocorneal adhesions and PAS is a helpful technique to optimally preserve the anterior segment anatomy during difficult cases of penetrating keratoplasty.Online Video Link: https://youtu.be/ZmQQhuOnAh4     

Significance of donor age in penetrating keratoplasty.

Because the significance of donor age in penetrating keratoplasty remains controversial, a study was undertaken to analyze the results of keratoplastics performed with older (greater than 70) and younger (less than 55) donor corneas. Thirty-seven eyes which received older donor corneas were divided into 4 diagnostic categories and were compared with 37 eyes having the same diagnosis which received younger donor corneas. The average follow-up for both groups was 24 months. There was no significant difference between the number of clear grafts in each group. It would appear that older donor corneas can withstand the surgical trauma of transplantation and remain clear for a relatively significant period.     

Endothelial keratoplasty using donor tissue not suitable for full-thickness penetrating keratoplasty

PURPOSE: To evaluate the use of corneal donor tissue deemed unsuitable for full-thickness penetrating keratoplasty (PK) for use in deep lamellar endothelial keratoplasty (DLEK) and to compare postoperative results to those of DLEK surgery using donor tissue that is suitable for PK. METHODS: Small-incision DLEK surgery was performed using 39 donor corneas unsuitable for PK. Thirty-five donors had anterior scars or opacities, 3 donors had pterygia within the 8-mm zone, and 1 had prior LASIK. All donor preparation was completed by manual stromal dissection. The DLEK surgical and postoperative courses were reviewed. Preoperative and 6-month postoperative results of this study group were compared with a control group consisting of the first 55 consecutive small-incision DLEK patients receiving donor corneas that had no criteria excluding them from use in PK. Four eyes in the study group and 1 eye in the control group had the confounding variables of the presence of an anterior-chamber lens or surgical vitrectomy with macular disease in the recipient eye. RESULTS: There was no significant difference in preoperative measurements of best spectacle-corrected visual acuity (BSCVA; P = 0.372), donor endothelial cell density (ECD; P = 0.749), or corneal topography [surface regularity index (SRI), P = 0.485; or surface asymmetry index (SAI), P = 0.154] between the 2 groups. For the patients receiving corneas deemed unacceptable for PK, at 6 months after surgery, the vision (P = 0.002) and corneal topography measurements improved significantly from before surgery (SRI, P < 0.001; SAI, P < 0.001), and there was no significant change in refractive astigmatism (P = 0.240). There was a significant difference in the vision at 6 months postoperatively between the overall study group and the control group, with the mean vision of the study group at 20/56 and the control group at 20/43 (P = 0.015). If eyes with known cystoid macular edema (CME) and vitrectomy are removed from each group, there is no significant difference in vision at 6 months between the study group and the control group (P = 0.110), with the average BSCVA of those receiving donor corneas unsuitable for PK equal to 20/48 (range, 20/25-20/200) and the average vision for those receiving PK-acceptable donor tissue equal to 20/43 (range, 20/20-20/80). The 6-month average refractive astigmatism of the study group was 1.12 +/- 0.99 D (range, 0.00-4.00 D), and the average endothelial cell count was 2064 +/- 396 cells/mm(2) (range, 1208-2957 cells/mm(2)). There was no significant difference in 6-month postoperative endothelial cell count (P = 0.443), refractive astigmatism (P = 0.567), or corneal topography (SRI, P = 0.332; SAI, P = 0.110) in study patients who received corneas unsuitable for PK compared with control patients who received corneas suitable for PK. CONCLUSIONS: Endothelial keratoplasty such as DLEK surgery with manual donor preparation broadens the donor pool by enabling corneas that cannot be used for PK to be used for selective endothelial transplantation without deleterious postoperative results.