Traumatic wound dehiscence after penetrating keratoplasty-a cause for concern

Investigation of mechanical strength and structure of corneal graft-host junction

Dehiscence is a common complication of corneal transplant surgery involving separating the graft from the host eye. The present article aims to investigate fundamental insights into the mechanical and structural aspects of the graft-host junction (GHJ) of a graft that survived in a patient for 13 years after penetrating keratoplasty (PK). Additionally, it adopts the sutur retention strength (SRS) test procedure defined in ISO:7198-2016 and aims to provide a comprehensive test protocol to study the biomechanics of the GHJ in extracted PK buttons. A 9 mm corneal button with GHJ was extracted from a 46-year-old patient who underwent PK 13 years back. The strength of the GHJ was quantified using the SRS test. Corresponding control results were obtained from the SRS tests of a corneoscleral button with no history of any refractive procedure. Birefringence, histological, and scanning electron microscopy (SEM) imaging were used to visualize the microstructural details of the GHJ. The strength of the GHJ was observed to be ten times lower than the native cornea. Histopathological features, such as fragmented Bowman's layer, and fibrosis with a clear demarcation line between host and graft tissue, were observed at the GHJ, suggesting a weak bond across the GHJ. The low strength of the GHJ in PK indicates the high susceptibility of the GHJ towards wound dehiscence.

Clinical outcomes of traumatic globe rupture in corneal graft patients

PURPOSE

This study reports the mechanisms, complications and graft survival following sight-threatening traumatic globe rupture in patients having previously undergone corneal transplantation in the same eye.

METHODS

A retrospective, observational, single-center consecutive cohort study at the Royal Victoria Infirmary, Newcastle upon Tyne, UK over a 20-year period. Medical records and Newcastle Corneal Transplantation Service electronic database (eNCTS) review was undertaken of all consecutive patients who underwent corneal transplantation with a history of traumatic globe rupture. Main outcome measures include mechanism of injury, final best-corrected distance visual acuity (BCDVA), graft survival and complications.

RESULTS

A total of 921 keratoplasties were undertaken between 1997 and 2017 with 24 (3.0%) patients identified with a history of traumatic globe rupture. A bimodal relationship of age and mechanism of trauma was observed. The mean age (SD) of individuals reporting cause as a fall was 71.5 (14.8) years, and 45.3 (20.8) years (P < 0.05) amongst individuals reporting accidental trauma or assault. The pre- and post-trauma mean (SD) LogMAR BCDVA was 0.6 (0.9) and 1.7 (1.0), respectively (P = 0.001). The overall graft-failure rate was 60.9% (11 grafts) during a mean (SD) follow-up period of 3.5 (4.1) years. Globe rupture with lens damage was associated with poorer final BCDVA (P < 0.05).

CONCLUSIONS

This study represents the first published series from England for this type of patient cohort. Overall visual outcomes were poor with a bimodal relationship of age and mechanism of trauma. Worse prognostic factors included lens and posterior segment complications. Re-grafting in these select group of patients may prove valuable.

Main issues in penetrating keratoplasty

This review explores contemporary challenges in penetrating keratoplasty (PK), focusing on technical intricacies, technological advancements, and strategies for preventing graft rejection. A systematic literature search from January 2018 to July 2023 was conducted across PubMed, Cochrane, Web of Science, Scopus, and EMBASE. The inclusion criteria comprised studies on PK and its comparison with other corneal pathologies, with emphasis on keratoconus (KC). Two independent reviewers screened studies, extracting relevant data. The review covers PK evolution, highlighting infra-red femtosecond lasers' impact on graft shapes, minimizing astigmatism, and enhancing wound healing. Graft rejection, a primary complication, is examined, detailing risk factors and preventive measures. Preoperative considerations, diagnostic techniques for rejection, and PK in KC are discussed. Postoperative care's significance, including intraocular pressure monitoring and steroid administration, is emphasized. The paper concludes with a comprehensive approach to prevent graft rejection, involving topical and systemic medications. An outlook on evolving monoclonal antibody research is presented. As the field progresses, personalized approaches and ongoing therapeutic exploration are expected to refine strategies, enhancing PK outcomes.

Advances in 3D bioprinting technology for functional corneal reconstruction and regeneration

Corneal transplantation constitutes one of the major treatments in severe cases of corneal diseases. The lack of cornea donors as well as other limitations of corneal transplantation necessitate the development of artificial corneal substitutes. Biosynthetic cornea model using 3D printing technique is promising to generate artificial corneal structure that can resemble the structure of the native human cornea and is applicable for regenerative medicine. Research on bioprinting artificial cornea has raised interest into the wide range of materials and cells that can be utilized as bioinks for optimal clarity, biocompatibility, and tectonic strength. With continued advances in biomaterials science and printing technology, it is believed that bioprinted cornea will eventually achieve a level of clinical functionality and practicality as to replace donated corneal tissues, with their associated limitations such as limited or unsteady supply, and possible infectious disease transmission. Here, we review the literature on bioprinting strategies, 3D corneal modelling, material options, and cellularization strategies in relation to keratoprosthesis design. The progress, limitations and expectations of recent cases of 3D bioprinting of artifial cornea are discussed. An outlook on the rise of 3D bioprinting in corneal reconstruction and regeneration is provided.

[Optical properties of the cornea after different modifications of penetrating keratoplasty]

PURPOSE

Comparative analysis of optical properties of the cornea after different modifications of penetrating keratoplasty.

MATERIAL AND METHODS

The study included 56 patients (56 eyes) divided into three study groups according to the surgery technique. Group I included 17 patients (17 eyes) after one-piece mushroom keratoplasty, group II - 21 patients (21 eyes) after two-piece mushroom keratoplasty and group III - 18 patients (18 eyes) after penetrating keratoplasty. In addition to standard examination methods, before surgery and in the course of the follow-up all patients underwent software-powered corneal densitometry on the anterior segment analyzer (Pentacam HR, "Oculus", Germany), as well as an assessment of the degree and regularity of postoperative astigmatism.

RESULTS

Comparison of the obtained results revealed with a high degree of confidence higher values of the total specific light scattering after two-piece mushroom keratoplasty throughout the entire observation period (p<0.05). At the same time, there was no statistically significant difference in visual acuity between the three study groups (p>0.05). A statistically significant increase in the level of induced astigmatism was revealed after penetrating keratoplasty.

CONCLUSION

The observed increase in light scattering after two-piece mushroom keratoplasty does not lead to a decrease in visual acuity. The interface in the optical zone of the cornea formed by a microkeratome does not affect the degree and regularity of induced astigmatism.

[Comparative evaluation of the results of one- and two-piece mushroom keratoplasty]

PURPOSE

To compare and evaluate the outcomes of one- and two-piece mushroom keratoplasty configurations for various corneal pathologies.

MATERIAL AND METHODS

A total of 32 patients (32 eyes) with corneal perforations, descemetocele and deep corneal opacities underwent surgery. Depending on the surgery technique, the patients were divided into 2 groups: group I (17 eyes) underwent manual one-piece mushroom keratoplasty according to our own technique; group II (15 eyes) underwent modified two-piece microkeratome-assisted mushroom keratoplasty according to the technique by M. Busin. All patients underwent clinical and functional studies before surgery and in the course of a 1-year follow-up.

RESULTS

Transparent engraftment of the cornea was achieved in 82 and 80% of cases; best corrected visual acuity (BCVA) averaged 0.57±0.19 and 0.53±0.17; spherical component of refraction varied from 1.25 to +5.5 and from 1.25 to 6.0 diopters; mean corneal astigmatism was 3.15±1.73 and 3.21±1.89 diopters in groups I and II, respectively. At 6 months after surgery, the mean endothelial cell density (ECD) was 2336±198 and 2291±175 cells/mm², at 1 year - 2041±189 and 1955±161 cells/mm² in groups I and II, respectively.

CONCLUSION

One- and two-piece mushroom keratoplasty is effective in surgical treatment of various corneal pathologies ensuring a high rate of transparent corneal engraftment. The revealed risk of false chambers formation between separate parts of the graft after the two-piece method could in most cases be eliminated by re-injecting air into the anterior eye chamber.

Comparison of the characteristics and outcomes of traumatic wound dehiscence after penetrating or Lamellar Keratoplasty for Keratoconus

PURPOSE

To examine the incidence, causes, characteristics, and the visual outcome of traumatic wound dehiscence (TWD) after penetrating keratoplasty (PK) compared to lamellar keratoplasty (LKP) for keratoconus.

METHODS

The medical records of all keratoconus patients undergoing TWD repair after PK or LKP over a 7-year period at the King Khaled Eye Specialist Hospital (KKESH), Riyadh were reviewed. Data were collected on patient demographics, interval between keratoplasty and trauma, and characteristics and visual outcomes of TWD.

RESULTS

During January 2006 to December 2012, 2863 eyes in KKESH underwent PK. Another 1716 eyes underwent LKP. Of these, 55 (1.9%) and 30 (1.7%) sustained TWD, respectively (p = 0.675). Approximately two-thirds of patients with traumatic wound dehiscence (TWD) were males in both groups (63.6% and 70.0%, respectively). The mean age at trauma was 24.6 ± 6.7 years (range 12-41 years) in the PK group compared with 22.6 ± 6.0 years (range 13-34 years) in the LKP group (p = 0.166). The median interval between keratoplasty and trauma was 6.2 (the interquartile range (IQR), 10.9) months for the PK group and 4.6 (IQR, 7.4) months for the LKP group (p = 0.116). At the last follow-up after wound repair, visual acuity was similar between the PK and LKP groups (p = 0.595).

CONCLUSION

In our study, the incidence of TWD after PK and LKP in patients with keratoconus was within the previously reported range of values. All patients undergoing these procedures, especially males, should receive adequate information regarding this lifelong risk, and the need for protective eye-wear and seeking early medical advice when complications occur.

Impact of COVID-19 related national lockdown on care of corneal transplantation patients at a tertiary eye care centre in India

Purpose

To study impact of COVID-19 related national lockdown on care of corneal transplantation patients at a tertiary eye centre in Andhra Pradesh state of South India.

Methods

Cross-sectional questionnaire-based study conducted at tertiary eye care centre in Andhra Pradesh state of South India, included 109 patients who underwent keratoplasty(full thickness or partial thickness) at our centre and who came for follow-up visit after lockdown. Factors such as type, indication, number of keratoplasties in the operated eye, and unusual clinical outcomes identified during visit after the lockdown, were studied. Uncorrected visual acuity, best corrected visual acuity, clarity of graft, graft-host junction apposition, intactness of sutures, intraocular pressure and disc status were compared on visits made before and after lockdown.

Results

During lockdown, 77.1% patients were properly using medications that was significantly (P = 0.0003) lower than that of before the lockdown (90.8%). After the lockdown, 82.3% patients were using medications properly that was comparable (P = 0.11) to that of during the lockdown (77.1%). The proportion of eyes with clear grafts and intact sutures decreased significantly after lockdown. The unusual outcomes observed after the lockdown were graft failure (36.7%), graft edema (11%), graft infiltrate(5.5%), phthysis bulbi (1.85%) and edematous graft cleared in eyes 3.7% eyes.

Conclusion

We noted significant drop in usage of medications from 91% before lockdown to 77% during lockdown and maintained at 83% after lockdown. Edematous grafts increased from 41% before lockdown to 54% after the lockdown. Intactness of sutures decreased from 82% before lockdown to 69% after lockdown.

Outcome of abdominal binder in midline abdominal wound Dehiscence in terms of pain, psychological satisfaction and need for reclosure

Objective

To assess the role of abdominal binder in patients with midline wound dehiscence after elective or emergency laparotomy in terms of pain, psychological satisfaction and need for reclosure.

Methods

It was a comparative study done at EAST Surgical Ward of Mayo Hospital, Lahore from 1^st January 2018 to 31^st December 2019. One hundred and sixty-two (162) patients were included in this study with post-operative midline abdominal wound dehiscence and after informed consent by consecutive non probability sampling technique. Patients were divided into two groups by lottery method into eighty-one patients each. Group-A included patients where abdominal binder was applied and Group-B included patients without abdominal binder. In both groups pain score, psychological satisfaction and need for reclosure was assessed and compared.

Results

Patients with abdominal binder shows significantly less pain (P value =0.000) and more psychological satisfaction (P value = 0.000) as compared to the patients where abdominal binder was not used. However, there was no difference in reducing the need for reclosure in patients who use abdominal binder (P value = 0.063).

Conclusion

Although abdominal binder helps in reducing the pain and improving the psychological satisfaction in patients with midline abdominal wound dehiscence yet it doesn't help in healing of wound and reclosure of the dehisced abdominal wound is needed.

Traumatic wound dehiscence after penetrating keratoplasty: Clinical features and outcome in 53 cases in Yemen

AIMS:

Penetrating keratoplasty (PKP) carries the risk of developing wound dehiscence, which can lead to vision loss. The main aim of this study is to analyze the management and outcome of surgery for traumatic wound dehiscence occurring in patients who had PKP.

SUBJECTS AND METHODS:

This retrospective study included post-PKP patients who sustained traumatic wound dehiscence at the Cornea Unit in Yemen Magrabi Eye Hospital between 2008 and 2016. Fifty-three eyes with a history of wound dehiscence were treated with primary wound closure. Patient files were reviewed for type and time of injury, distance visual acuity (VA), and outcome.

RESULTS:

Ruptured globe with dehiscence of wound occurred on average 2.4 years (3 months to 13 years) after PKP. The mean age at wound dehiscence was 22.27 years and males accounted for 77.4% (41). All patients were managed with primary closure of the wound. Lensectomy of traumatic or dislocated lens was the most frequent additional surgical procedure (14, 26.4%), followed by anterior vitrectomy (6, 11.3%). In the end, 43 (81.1%) grafts remained clear. In the last follow-up, 34 eyes (64.1%) had best-corrected VA of 20/200 or better and two eyes had no perception of light.

CONCLUSION:

Rupture globe and wound dehiscence occurs after PKP at the graft–host junction. Wound dehiscence is a lifelong risk after PKP and wound weakness persisted for a long period after PKP. Visual outcome and graft survival are generally poor after the injury, and the restoration of a satisfactory visual result is possible if treated early.

Finite Element Analysis of Air Gun Impact on Post-Keratoplasty Eye

Purpose

Due to the mechanical vulnerability of eyes that have undergone penetrating keratoplasty (PKP), it is clinically important to evaluate the possibility of corneal wound dehiscence by blunt impact. We have previously developed a simulation model resembling a human eye based on information obtained from cadaver eyes and applied three-dimensional finite element analysis (FEA) to determine the physical and mechanical response to an air gun impact at various velocities on the post-PKP eye.

Methods

Simulations in a human eye model were performed with a computer using a FEA program created by Nihon, ESI Group. The air gun pellet was set to impact the eye at three-different velocities in straight or 12° up-gaze positions with the addition of variation in keratoplasty suture strength of 30%, 50% and 100% of normal corneal strength.

Results

Furthermore to little damage in the case of 100% strength, in cases of lower strength in a straight-gaze position, wound rupture seemed to occur in the early phase (0.04-0.06 ms) of impact at low velocities, while regional break was observed at 0.14 ms after an impact at high velocity (75 m/s). In contrast, wound damage was observed in the lower quadrant of the suture zone and sclera in 12° up-gaze cases. Wound damage was observed 0.08 ms after an impact threatening corneoscleral laceration, and the involved area being larger in middle impact velocity (60 m/s) simulations than in lower impact velocity simulations, and larger damaged area was observed in high impact velocity cases and leading to corneoscleral laceration.

Conclusion

These results suggest that the eye is most susceptible to corneal damage around the suture area especially with a straight-gaze impact by an air gun, and that special precautionary measures should be considered in patients who undergo PKP. FEA using a human eyeball model might be a useful method to analyze and predict the mechanical features of eyes that undergo keratoplasty.

Comparative Evaluation Of Clinical Characteristics And Visual Outcomes Of Traumatic And Non-Traumatic Graft Dehiscence Following Corneal Transplantation Surgery

Purpose

To compare patient demographics, clinical associations and visual outcomes between traumatic and non-traumatic wound dehiscence, following corneal transplantation.

Methods

Retrospective review of all patients presenting with post-keratoplasty wound dehiscence to the Royal Victorian Eye and Ear Hospital between January 2005 and December 2017. Patients with wound dehiscence following keratoplasty of any cause were included.

Results

Of 71 eyes from 71 patients included, 60 (85%) were penetrating keratoplasty patients. The mean age was 56.4 years (SD=22.7, range 17.6-97) and 62% (n = 44) of patients were male. There were 28 (39%) cases of traumatic dehiscence and 43 (61%) cases of non-traumatic dehiscence. The median time interval from keratoplasty to dehiscence was significantly less in non-traumatic patients than traumatic patients (0.2 years, IQR 0.1-2.0 vs 2.3 years, IQR 0.3-14.8, p=0.01). There was no significant difference in best-corrected visual acuity at 6 months between traumatic and non-traumatic dehiscence (6/60 vs 6/36, p=0.62), suture technique (continuous vs interrupted, p=0.12), or graft type (penetrating keratoplasty vs deep anterior lamellar keratoplasty) after adjusting for keratoconus (p=0.41).

Conclusion

Post-keratoplasty wound dehiscence is a serious complication and can cause significant loss of vision. While the risk of dehiscence is lifelong, the first 3 years post-keratoplasty carry the highest risk, with non-traumatic dehiscence tending to occur earlier than traumatic dehiscence.

[Modern modifications of penetrating keratoplasty with complex operative incision]

The basic principle of modern keratoplasty is selectivity, i.e. the choice of whether to replace only the affected corneal layer. However, when layer-by-layer and interlayer transplantation is not indicated, the method of choice is conventional penetrating keratoplasty. An alternative can be its modifications with complex profiles of the transplant edges and the bed, which are better justified in terms of pathogenesis. The most popular among them are mushroom, zig-zag and top-hat. These surgeries combine optical benefits of penetrating keratoplasty as they do not involve dissection of the corneal optical zone and can negate - to a certain degree - its main downsides such as low trauma tolerance of the postoperative scar, significant level of postoperative astigmatism, and increased visual rehabilitation time. Mushroom-shaped incisions can be performed manually with a femtosecond laser or a microkeratome, zig-zag incision - only with a femtosecond laser. Considering the diversity of keratoplasty modifications with complex operative incisions, further research is required for evaluation of their clinical effectiveness and analysis of postoperative complications.

Long-term Outcomes of Repeated Corneal Transplantations: A Prospective Dutch Registry Study

PURPOSE

To compare long-term outcomes of repeated corneal transplantations (CT), based on primary indication (Fuchs endothelial dystrophy [FED] vs pseudophakic bullous keratoplasty [PBK]), surgical technique (penetrating keratoplasty [PK] vs endothelial keratoplasty [EK]), and indication for repeated grafting.

METHODS

In this nonrandomized treatment comparison with national registry data (Netherlands Organ Transplantation Registry, NOTR), data on all consecutive repeated CT following primary PK or EK for FED and PBK between 1994 and 2015 were analyzed, with a maximal follow-up of 5 years. Regraft survival was analyzed using Kaplan-Meier survival curves and univariable and multivariable Cox regression analysis. Secondary outcomes best-corrected visual acuity, spherical equivalent, and refractive astigmatism were compared using linear mixed-model analysis.

RESULTS

A total of 332 repeated CT were analyzed. The number of regrafts increased significantly between 2007 and 2015 (P = .001). Overall 5-year regraft survival was 60% and was higher for FED vs PBK (77% vs 45%, HR = 0.40, P = .001), and re-EK vs re-PK (81% vs 55%, HR = 0.51, P = .041). However, multivariable analysis showed no significant difference in survival based on primary indication, surgical technique, and indication for regrafting. Corrected for baseline, secondary outcomes also did not differ between groups.

CONCLUSIONS

We found a significant increase in repeated CT, coinciding with the introduction of EK in the Netherlands. While univariable analysis suggested better overall regraft survival for FED and (re-)EK, multivariable analysis showed no such difference. This may be owing to allocation of favorable cases to undergo (re-)EK. Similarly, secondary outcomes were determined by the primary CT technique.

SMILE Rescue: Delayed Lenticule Removal in a Patient With High Myopia

PURPOSE

To report successful stromal lenticule extraction, 18 weeks after an aborted small incision lenticule extraction (SMILE) procedure.

METHODS

Case report.

RESULTS

SMILE was planned in both eyes in another center to correct high myopia. The right eye was treated uneventfully with immediate lenticule extraction and normal postoperative corneal and topographic appearance. Femtosecond laser treatment was applied to the left eye, but the lenticule could not be removed and the procedure was aborted. Eighteen weeks later, lenticule extraction was attempted again with success. Uncorrected distance visual acuity improved from counting fingers to 20/15, with a successful refractive outcome as planned.

CONCLUSIONS

Delayed lenticule extraction was successful in achieving the target refractive outcome. To the authors' knowledge, this is the first case of successful delayed lenticule extraction following an incomplete SMILE procedure. Target refractive outcomes were achieved and there were no postoperative complications. [J Refract Surg. 2017;33(3):199-202.].

Rescuing the host Descemet's membrane in full-thickness traumatic wound dehiscence in deep anterior lamellar keratoplasty: intraoperative optical coherence tomography (iOCT)-guided technique

Optimal visual recovery following full-thickness traumatic wound dehiscence in a case of operated deep anterior lamellar keratoplasty (DALK) is rarely seen. Here we report a case of 22-year-old male patient presented to our casualty department with complaint of sudden-onset diminution of vision in his right eye following blunt trauma of 1 day duration. DALK had been performed 11 months ago for advanced keratoconus in the same eye. Best-corrected visual acuity (BCVA) in the right eye was hand movement close to face with accurate projection of rays and in the left eye was 20/20. Slit-lamp examination showed the presence of inferior 180° graft dehiscence with broken sutures and shallow anterior chamber with corneal oedema. Repair of the dehiscence with descemetopexy was done under the guidance of intraoperative optical coherence tomography with the successful rescuing of the host Descemet's membrane. BCVA at 6 months follow-up was 20/40.

Globe Rupture of a Post-LASIK Keratectasia Eye From Blunt Trauma

PURPOSE

To report a case of globe rupture in a patient with post-laser in situ keratomileusis (LASIK) ectasia after blunt trauma.

METHODS

Observational case report.

RESULTS

A 42-year-old man with a history of post-LASIK ectasia sustained paracentral corneal rupture secondary to blunt trauma from a fist to his left eye (OS). Slit-lamp examination revealed rupture in the posterior stroma (inferior paracentral) of the OS with an overlying intact LASIK flap; however, the inferior edges of the LASIK flap were Seidel positive. The anterior chamber was flat. Although he was initially managed with cyanoacrylate glue and a bandage contact lens, the patient eventually required tectonic penetrating keratoplasty. The postoperative course was unremarkable, and over 1 year later, the visual acuity OS was 20/25 with -7.50 + 2.00 × 0.50.

CONCLUSIONS

Globe rupture from blunt trauma has not been shown to be more common in patients with a history of LASIK. Although blunt trauma to the post-LASIK globe would generally incur a similar risk of rupture to that of the normal eye, keratectasia after LASIK may predispose the globe to rupture.

Traumatic Wound Dehiscence after Keratoplasty: Characteristics, Risk Factors, and Visual Outcome

Purpose. The study aimed at evaluating the patients' characteristics, risk factors, complications, and visual outcome of traumatic wound dehiscence after keratoplasty. Patients and Methods. A retrospective case series that included 20 eyes of 20 patients who had undergone a previous keratoplasty procedure followed by traumatic wound dehiscence. Records of the selected patients were reviewed. The mean duration of follow-up after repair was 21 months. Included patients were recalled for the final follow-up visit. Results. The procedure of corneal transplantation was penetrating (PKP) in 16 eyes and deep anterior lamellar keratoplasty (DALK) in 4 eyes. The associated anterior segment injuries included iris prolapse in 17 eyes and lens extrusion in 12 eyes. The associated posterior segment injuries included vitreous hemorrhage in 11 eyes and retinal detachment in 4 eyes. The final BSCVA was 0.1 or better in 5 cases (25 %) and was better than hand motions (HM) to less than 0.1 in 7 cases (35 %). Conclusion. Traumatic wound dehiscence following keratoplasty results in poor visual outcome. Cases following DALK may have less wound extent and better final visual outcome. The dehiscence seems most likely to occur during the first year.

Endothelial keratoplasty versus penetrating keratoplasty for Fuchs endothelial dystrophy

BACKGROUND

Fuchs endothelial dystrophy (FED) is a condition in which there is premature degeneration of corneal endothelial cells. When the number of endothelial cells is reduced to a significant degree, fluid begins to accumulate within the cornea. As a result, the cornea loses its transparency and the individual suffers a reduction in vision. The only successful surgical treatment for this condition is replacement of part or all of the cornea with healthy tissue from a donor. The established procedure, penetrating keratoplasty (PKP), has been used for many years and its safety and efficacy are well known. Endothelial keratoplasty (EK) techniques are relatively new surgical procedures and their safety and efficacy relative to PKP are uncertain.

OBJECTIVES

The objective of this review was to compare the benefits and complications related to two surgical methods (EK and PKP) of replacing the diseased endothelial layer of the cornea with a healthy layer in people with FED.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2014, Issue 1), MEDLINE (January 1950 to January 2014), EMBASE (January 1980 to January 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to January 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) and ClinicalTrials.gov (www.clinicaltrials.gov). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 27 January 2014.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing EK versus PKP for people (of any age and gender) who had been clinically diagnosed with FED.

DATA COLLECTION AND ANALYSIS

Two authors independently screened the search results, assessed trial quality and extracted data using the standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We included three RCTs that enrolled a total of 139 eyes of 136 participants and analysed 123 (88%) eyes. Two RCTs randomised eyes into either the endothelial keratoplasty (EK) group or penetrating keratoplasty (PKP) group and one RCT randomised eyes into either the femtosecond laser-assisted endothelial keratoplasty (FLEK) group or PKP group. The RCTs comparing EK with PKP did not show any significant differences between procedures with respect to best corrected visual acuity (BCVA) at two years (mean difference (MD) 0.14 logMAR; 95% confidence interval (CI) -0.08 to 0.36; P = 0.23) or at one year (MD 0.09 logMAR; 95% CI -0.05 to 0.23; P = 0.22), whereas the trial comparing FLEK with PKP showed significantly better BCVA after PKP (MD 0.20 logMAR; 95% CI 0.10 to 0.30; P = 0.0001). Only one RCT reported on irregular astigmatism (higher-order aberration), which was less with EK than PKP (MD -1.20 µm; 95% CI -1.53 to -0.87; P < 0.001). Only one RCT reported on endothelial cell counts (lower after FLEK than PKP: MD -969 cells/mm²; 95% CI -1161 to -777; P < 0.001), primary graft failure (higher after FLEK than PKP: RR 7.76; 95% CI 0.41 to 145.22; P = 0.10), and graft rejection (more after FLEK than PKP: RR 1.11; 95% CI 0.07 to 17.12; P = 0.94). Only one RCT reported that 27.8% of participants had graft dislocation, 2.8% had epithelial ingrowth and postoperative pupillary block, and 13.9% had intraocular pressure (IOP)-related problems in the FLEK group compared with the PKP group, in whom 10% had suture-related problems, 5% had wound dehiscence and 10% had suture revision to correct astigmatism. Overall, the adverse events in the FLEK group appeared to be more frequent than in the PKP group. No trials reported information about quality of life or economic data. The overall methodological quality of the three trials was not satisfactory as most did not perform allocation concealment or masking of participants and outcome assessors, and all trials had a small sample size.

AUTHORS' CONCLUSIONS

The rapid growth of endothelial keratoplasty as the treatment of choice for FED is based upon the belief that visual recovery is more rapid, surgically induced astigmatism (regular and irregular) is less and rates of transplant rejection are lower with EK. This change in practice also assumes that the rates of long term transplant survival are equal for the two procedures. The practical differences between the surgical procedures mean that visual recovery is inherently more rapid following EK, but this review found no strong evidence from RCTs of any difference in the final visual outcome between EK and PKP for people with FED. This review also found that higher order aberrations are fewer following EK but endothelial cell loss is greater following EK. The RCTs that we included employed different EK techniques, which may have a bearing on these findings. EK procedures have evolved over the years and can be performed using different techniques, for example deep lamellar endothelial keratoplasty, Descemets stripping endothelial keratoplasty (DSEK), Descemets stripping automated endothelial keratoplasty (DSAEK), femtosecond laser-assisted endothelial keratoplasty and Descemet membrane endothelial keratoplasty (DMEK). More RCTs are needed to compare PKP with commonly performed EK procedures such as DSEK, DSAEK and DMEK in order to determine the answers to two key questions, whether there is any difference in the final visual outcome between these techniques and whether there are differences in the rates of graft survival in the long term?

Traumatic wound dehiscence after deep anterior lamellar keratoplasty

PURPOSE

To analyze the outcomes of traumatic wound dehiscence after deep anterior lamellar keratoplasty (DALK).

DESIGN

Retrospective and interventional case series.

METHODS

SETTING

Single hospital.

PATIENTS

A total of 338 consecutive cases were reviewed. Eleven eyes that had wound dehiscence related to ocular trauma were included.

MAIN OUTCOME MEASURES

Incidence and causes, best-corrected visual acuity (BCVA), and endothelial cell density were evaluated. Complications and secondary surgeries were recorded.

RESULTS

Seven patients were male (63.6%) and 4 patients were female (36.4%), with a mean age of 30.6 years (range, 24-40 years). The incidence of wound dehiscence was 3.2% (11/338). The mean interval between the initial DALK procedure and wound dehiscence was 9.45 months (range, 2-16 months). The mean follow-up time was 6 years. The most common trauma was a fist blow injury (36.3%). Descemet membrane perforation was observed in 8 eyes (72.7%); lens damage and vitreous prolapse occurred in 2 eyes (18.1%). The final BCVA was 0.51 and was maintained in 4 eyes (36.3%). At the final visit, 10 grafts (90.9%) were clear. The mean endothelial cell loss was 55.8% between before DALK and last visit.

CONCLUSION

Although the intact Descemet membrane protects against dehiscing traumas after DALK, a relative weakness at the graft-host junction tends to persist and a severe deforming force may result in graft dehiscence. This case series indicates that despite the fact that the visual results following the repair are acceptable, corneal endothelium seems to be subjected to severe damage, which puts graft survival chances at risk in the long term.

Clinical features of single and repeated globe rupture after penetrating keratoplasty

BACKGROUND

In this paper, we report our experience of the clinical features of single and repeated globe rupture after penetrating keratoplasty.

METHODS

We undertook a retrospective analysis of single and repeated globe ruptures following keratoplasty in eight eyes from seven consecutive patients referred to Kanazawa University Hospital over a 10-year period from January 2002 to March 2012. We analyzed their ophthalmic and demographic data, including age at time of globe rupture, incidence, time interval between keratoplasty and globe rupture, cause of rupture, complicated ocular damage, and visual outcome after surgical repair.

RESULTS

Five patients (71.4%) experienced a single globe rupture and two patients (28.6%) experienced repeated globe ruptures. Patient age at the time of globe rupture was 75.4 ± 6.8 (range 67-83) years. Four of the patients were men and three were women. During the 10-year study period, the incidence of globe rupture following penetrating keratoplasty was 2.8%. The time interval between penetrating keratoplasty and globe rupture was 101 ± 92 months (range 7 months to 23 years). The most common cause of globe rupture in older patients was a fall (n = 5, 79.8 ± 3.7 years, all older than 67 years). Final best-corrected visual acuity was >20/200 in three eyes (37.5%). In all except one eye, globe rupture involved the graft-host junction; in the remaining eye, the rupture occurred after disruption of the extracapsular cataract extraction wound by blunt trauma.

CONCLUSION

Preventative measures should be taken to avoid single and repeated ocular trauma following penetrating keratoplasty.

Suturing techniques and postoperative management in penetrating keratoplasty in the United Kingdom

Aims

To report on the suturing techniques and aspects of postoperative management in penetrating keratoplasty in the United Kingdom.

Methods

A postal questionnaire was sent to 137 ophthalmic consultants identified from a Royal College of Ophthalmology database as having a special interest in anterior segment surgery. The questionnaire surveyed surgeon preferences for surgical and suturing technique for penetrating keratoplasty surgery, and the postoperative care of corneal grafts.

Results

In all, 68% of questionnaires were completed and returned: 73% of respondents used a Flieringa ring or equivalent, 94% routinely used cardinal sutures, with 50.5% removing them at the end of the procedure. The most common suturing technique for routine penetrating keratoplasty was a single continuous suture (35%). In these cases, a 10/0 nylon suture was used by 89%. Sixty-six percent changed their technique in high-risk cases, 52% used a 3-1-1 knot, and 75% made a distinction between a reef and granny knot, with 76% using a reef. Thirty percent buried the knots within the donor material, and 29% within the host tissue. Twenty-five percent had no routine time for graft suture removal, but 41% removed them between 1 and 2 years post-surgery. After suture removal, 98% used steroids and 88% used topical antibiotics. Thirty-four percent stopped topical steroids before suture removal, with 38% stopping topical steroids more than 3 months prior to suture removal.

Conclusion

This survey demonstrates that there is considerable variation in suturing techniques and postoperative care for penetrating keratoplasty. These significant variations in practice need to be considered when interpreting outcomes and research.

Traumatic wound rupture after Boston type 1 keratoprosthesis implantation

OBJECTIVE

To describe the incidence, characteristics, causes, treatment, and outcomes of traumatic wound rupture in patients with Boston type 1 keratoprosthesis (KPro).

DESIGN

Retrospective case series.

PARTICIPANTS

We studied 136 eyes of 122 patients who underwent KPro implantation at a single institute between November 2004 and May 2011.

METHODS

A chart review was performed to determine the incidence, characteristics, causes, treatments, and outcomes of traumatic wound rupture.

RESULTS

The 4 eyes of 4 patients that sustained traumatic wound rupture resulted in an incidence of traumatic wound rupture of 2.9% (4/136). This complication occurred, on average, at 4.2 months (range, 1-9 months) after the KPro was implanted. All ruptures occurred at the graft-host junction. The 2 eyes that had complete keratoprosthesis extrusion experienced decreased vision postrupture, from hand motions to no light perception, and 20/300 to count-fingers vision, respectively. One eye that had 4 clock hours of superior wound rupture recovered vision postrupture from light perception to 20/40. One eye that had 2 clock hours of superior wound rupture maintained a stable vision of 20/125 after repair.

CONCLUSIONS

The incidence of traumatic wound rupture after keratoprosthesis is comparable to that after penetrating keratoplasty. Patients should be aware that traumatic rupture is a lifelong concern and should use protective measures to prevent this complication from occurring.

Traumatic wound dehiscence after penetrating keratoplasty: case series and literature review

PURPOSE

Blunt trauma after penetrating keratoplasty (PK) is a high risk for wound rupture at the donor-recipient interface. We present 6 cases of traumatic wound dehiscence after PK; we describe the morphologic and functional outcome after surgical intervention and provide a review of the current literature.

METHODS

Six patients with a traumatic wound dehiscence after PK were analyzed retrospectively from the files of the University Eye Hospital Hamburg-Eppendorf (1998-2009). In addition, a comprehensive literature review was performed.

RESULTS

The indications for PK were keratoconus, corneal scars, and Fuchs endothelial dystrophy. The age range was 22-81 years; the time span between PK and globe rupture was 1 month to 27 years. The cause of the dislocation was a fall or blunt trauma, through a branch, airbag, fist, or finger. The corrected distance visual acuity (CDVA) pretrauma ranged between hand movement and 20/32. The CDVA after wound repair was 20/400 to 20/25 depending on the severity of the trauma. In 3 of the 6 cases, visual rehabilitation was superior to the pretrauma vision, whereas in 3 cases the pretrauma CDVA could not be reached.

CONCLUSIONS

If a timely and adequate treatment of the traumatically dislocated transplant can be given, it is likely that the transplant will survive. Nevertheless, severely reduced visual acuity (i.e., < hand movement) and lens damage at the time of trauma are the most reliable predictors for the final visual outcome. A permanent loss of visual acuity is related rather to the intraocular damage (vitreous loss, vitreous bleeding, retinal tears, and retinal detachment) than to the readapted transplant itself.

Traumatic wound dehiscence after deep anterior lamellar keratoplasty

A 5-year-old boy who had undergone deep anterior lamellar keratoplasty (DALK) in the right eye 8 months earlier presented with a full-thickness graft-host junction dehiscence and iris prolapse following an injury with a rubber ball. The junction was resutured and the graft became clear within 5 weeks. To our knowledge, this is the first reported case of wound dehiscence after DALK in a child. Although Descemet's membrane might be considered a protective barrier following DALK, the graft-host junction remains vulnerable and can rupture with blunt trauma.

Endothelial keratoplasty versus penetrating keratoplasty for Fuchs endothelial dystrophy

BACKGROUND

Fuchs endothelial dystrophy (FED), first described by Ernst Fuchsis in 1910, is a condition in which there is premature degeneration of corneal endothelial cells. When the number of endothelial cells is reduced to a significant degree fluid begins to accumulate within the cornea. As a result the cornea loses its transparency and the individual suffers a reduction in vision. The only successful surgical treatment for this condition is replacement of part or all of the cornea with healthy tissue from a cadaveric donor. The established procedure, penetrating keratoplasty (PKP), has been used for many years and its safety and efficacy are well known. Endothelial keratoplasty (EK) is a relatively new surgical procedure and the safety and efficacy relative to PKP are unknown.

OBJECTIVES

The objective of this review is to collate information on the benefits and complications related to two surgical methods (PKP and EK) of replacing the diseased endothelial layer of the cornea with a healthy layer in people with FED.

SEARCH STRATEGY

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 2), MEDLINE (January 1950 to February 2011), EMBASE (January 1980 to February 2011), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to February 2011), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) and ClinicalTrials.gov (www.clinicaltrials.gov). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 6 February 2011.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing EK versus PKP for people (of any age and gender) who had been clinically diagnosed with FED. When assessing the primary and secondary outcome measures, only RCTs were included in the analysis. As per our protocol a description of data from non-randomised comparative studies is also reported. As RCTs may not detect differences in frequency of adverse events, when assessing these we included data from cohort studies with more than 50 participants and a follow-up of up to five years.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

The electronic searches identified one RCT, five non-randomised comparative studies and 34 cohort studies with a sample size of over 50 participants for inclusion. The RCT was conducted in the USA and included 28 eyes of 25 participants with FED. Although this is a very good RCT, there may be potential for bias due to lack of masking of assessors and possible selective reporting not being clearly reported. In this RCT, comparing EK versus PKP, best corrected visual acuity (BCVA) was similar at 24 months (PKP 0.20 ± 0.20 logMAR; EK 0.34 ± 0.35 logMAR; P = 0.23) and higher order aberrations (HOAs) (deviations of the performance of an optical system from the predictions of paraxial optics) were lower with EK. No other data were reported by the trial. Based on data obtained from both non-randomised comparative studies and individual cohort studies the endothelial rejection rate was between 5.3% and 23.2% for PKP and 2% and 4% for EK. However the mean follow-up duration in the EK cohort studies was noticeably shorter. The rate of EK graft dislocation requiring repositioning ranged from 3% to 63%, with the majority of studies having a rate of < 10%.

AUTHORS' CONCLUSIONS

There is no high quality evidence that EK is superior to PKP in the treatment of FED considering the studies that satisfied our primary and secondary outcome measures. One RCT demonstrated that HOAs are lower following EK and some lower quality evidence suggests that endothelial rejection episodes may be less with EK. These findings should be interpreted with caution as they are based on data with risk of biases. Further RCTs of visual and refractive outcomes needs to be performed in this field, comparing EK to PKP, with a larger sample size and at least five years of follow up. To avoid bias due to a surgeon's learning curve, procedures should be performed by experienced surgeons only. Quality of life and vision should also be evaluated. The risk of endothelial rejection will be difficult to address in the context of a RCT because of power considerations but large non-randomised comparative case series and corneal graft registry outcome data will be useful in this regard.

Postoperative risk factors influencing corneal graft survival in the Singapore Corneal Transplant Study

PURPOSE

To determine postoperative risk factors that influence long-term corneal graft survival.

DESIGN

Prospective cohort study.

METHODS

Nine-hundred one consecutive penetrating keratoplasty procedures for optical, therapeutic, or tectonic indications from the Singapore Corneal Transplant Study. Univariate and multivariate analysis was performed for postoperative risk factors; Cox proportional hazards regression with a time-dependent covariate was used for preoperative, intraoperative, donor, and postoperative risk factors in a combined model.

RESULTS

Raised intraocular pressure (20.7%) was the most common complication, followed by rejection (18.2%), whereas glaucoma surgery (7.9%) and repeat grafting (7.3%) were the most common procedures after penetrating keratoplasty. The primary graft failure rate was 1.4%, and late failure was seen in 9.4% of eyes. In the combined regression model, rejection (hazard ratio [HR], 3.4; P = .00), microbial keratitis (HR, 3.6; P = .00), endophthalmitis (HR, 7.7; P = .00), primary disease recurrence (HR, 73.9; P = .00), wound dehiscence (HR, 2.8; P = .02), lid surgery (HR, 2.3; P = .02), glaucoma surgery (HR, 2.46; P = .02), and repeat grafting (HR, 3.2; P = .00) were the significant postoperative failure predictors; the significant preoperative and intraoperative factors identified were female gender, graft size of less than 7 mm and more than 9 mm, primary diagnosis, preoperative inflammation, and preexisting perforation.

CONCLUSIONS

Postoperative complications and operative procedures after grafting have an adverse effect on graft survival.

[Traumatic wound dehiscence after keratoplasty]

PURPOSE

To assess the patient characteristics, risk factors, and outcomes of penetrating keratoplasty wound dehiscence.

PATIENTS AND METHOD

Retrospective chart review of 11 eyes of 11 patients with corneal grafts who underwent repair of penetrating keratoplasty wound dehiscence from January 1986 to January 2006 in the Ophthalmology Department at the Besançon Minjoz Hospital (France).

RESULT

The mean time between penetrating keratoplasty and wound dehiscence was 3.3 years (range, 1-140 months). In all cases, dehiscence involved the junction between graft and host. The mean age at time of wound dehiscence was 47 years (range, 23-89 years). Falls were the most common mechanism of trauma, especially in the elderly population. There was a wide range of visual outcomes in the 11 patients, with six patients with best corrected visual acuity less than 1/20. There were no cases of endophthalmitis.

CONCLUSION

Patients with corneal transplants have a life-long risk for wound traumatic dehiscence. This complication may be reduced by the regular use of eye protection by all corneal transplantation patients.