Pediatric corneal transplantation: techniques, challenges, and outcomes

Pediatric corneal transplant is a highly demanding and technically challenging procedure for the cornea surgeon in today's era. These cases pose unique challenges in clinical and surgical management. The indications of pediatric corneal transplant can be therapeutic, tectonic, optical, and cosmetic. Pediatric patients undergoing corneal transplants are at a high risk of graft infection, failure, rejection, dehiscence, and amblyopia due to young age, robust immune system, increased incidence of trauma, and compliance issues. The other factors contributing to graft failure can be allograft rejection, secondary glaucoma, corneal vascularization, multiple surgeries, vitreous prolapse, and lack of treatment compliance. A successful corneal transplant in children depends on meticulous preoperative evaluation, uneventful surgery, the expertise of a corneal surgeon, and regular and timely postoperative follow-up. Therapeutic and optical penetrating keratoplasty are the most commonly performed transplants in children. However, with the advancements in surgical technique and management protocol, the current focus has shifted toward lamellar keratoplasty. Lamellar keratoplasty offers early visual recovery and potentially fewer complications. Visual rehabilitation through corneal transplant in otherwise blind eyes can be a boon for the children. Recently, keratoprostheses have been promising in children with multiple graft failures. The current review gives insights into epidemiology, etiology, indications, clinical characteristics, investigations, management options, recent advances, and the future of pediatric corneal transplants. As surgical techniques continue to grow and comprehension of pediatric corneal transplants is improving, we can safeguard these eyes with the best possible anatomical and functional outcomes.

Simultaneous tectonic Descemet stripping endothelial keratoplasty and tectonic Bowman layer transplant for the management of corneal perforation

AIM

To report the outcomes of three cases of corneal perforation managed with simultaneous tectonic Descemet stripping endothelial keratoplasty (t-DSEK) and tectonic Bowman layer transplant (t-BLT) as an alternative to tectonic penetrating keratoplasty (t-PKP).

METHODS

Three eyes of three patients receiving simultaneous t-DSEK and t-BLT for corneal perforation were included. The technique for DSEK was modified depending on individual requirements. The t-BLT technique was standardised using an 8 mm graft and fixated with a running suture. Success was measured by the ability of this procedure to close a corneal perforation.

RESULTS

All three cases achieved tectonic eye globe restoration and remained stable during the minimum 3-month observation period. Reinterventions were relatively common: 2 cases required amniotic membrane transplant for persistent epithelial defects. One case required DSEK rebubbling. One case developed angle closure glaucoma requiring surgical peripheral iridectomy.

CONCLUSION

Simultaneous t-DSEK and t-BLT may be a useful strategy for the management of corneal perforation as an alternative management to t-PKP for selected cases.

Corneal Optical Densitometry in the Evaluation of 2-Year Graft Function Following Endothelial Keratoplasty

This study aimed to assess clinical application of the Scheimpflug corneal tomography for objective evaluation of corneal optical density in eyes undergoing Descemet's stripping endothelial keratoplasty (DSEK). In this prospective study, 39 pseudophakic eyes with bullous keratopathy were enrolled. All eyes underwent primary DSEK. Ophthalmic examination included best corrected visual acuity (BCVA) measurement, biomicroscopy, Scheimpflug tomography, pachymetry, and endothelial cell count. All measurements were taken preoperatively and within a 2-year follow-up period. Gradual BCVA improvement was observed in all patients. After two years, the mean and median BCVA values were 0.18 logMAR. A decrease in central corneal thickness was noted only during the first 3 months postoperatively and was followed by a gradual increase. Corneal densitometry decreased constantly and most significantly in the first 3 months postoperatively. The consecutive decrease in endothelial cell count of the transplanted cornea was most significant during the first 6 months postoperatively. Six months postoperatively, the strongest correlation (Spearman's r = -0.41) with BCVA was found for densitometry. This tendency was maintained throughout the entire follow-up period. Corneal densitometry is applicable for objective monitoring of early and late outcomes of endothelial keratoplasty, showing a higher correlation with visual acuity than pachymetry and endothelial cell density.

Two-Step Iridocorneal Endothelial Syndrome Management: Endocapsular Intraocular Lens and Artificial Iris Followed by Descemet's Stripping Automated Endothelial Keratoplasty

A 54-year-old female presented with complaints of glare and progressive visual loss OS with a corrected distance visual acuity (CDVA) OS of 20/100. The patient had grade 1 corneal edema with a "beaten bronze" appearance on specularly reflected light, pseudopolycoria, and a nuclear sclerotic cataract. The diagnosis of nuclear cataract and progressive iris atrophy iridocorneal endothelial (ICE) syndrome was made, and the patient underwent uneventful phacoemulsification with capsular bag placement of an AcrySof SA60AT intraocular lens combined with pseudopolycoria repair using an endocapsular Model A REPER artificial iris. Six months later, the patient was submitted to a Descemet's stripping automated endothelial keratoplasty (DSAEK) procedure, and 6 months after that the CDVA was 20/32 with no corneal edema and normal intraocular pressure. This two-step surgical approach, combining phacoemulsification and endocapsular foldable iris prosthesis placement followed by DSAEK, may be considered a promising option to successfully treat progressive iris atrophy ICE syndrome patients.

Femtosecond laser semi-assisted Descemet stripping endothelial keratoplasty: 2-year outcomes of endothelial cell loss and graft survival

Purpose

To assess 2-year endothelial cell loss and graft survival after femtosecond laser semi-assisted Descemet stripping endothelial keratoplasty (FLS-DSEK).

Methods

In this prospective and noncomparative study carried out at Eye Hospital of Shandong First Medical University, 85 eyes (84 patients) with endothelial dysfunction receiving FLS-DSEK (n=62, 75.9%) or FLS-DSEK combined with phacoemulsification cataract surgery and intraocular lens implantation (n=23, 27.1%) from 2013 through 2016 were included. The graft endothelial cell loss, endothelial graft thickness, visual acuity, and complications after surgery were evaluated.

Results

Thin endothelial grafts were all successfully prepared, with no occurrence of perforation. The rate of endothelial cell loss was 17.4%, 18.8%, 19.9%, and 26.7%, and the central graft thickness was 113±54 μm, 102±40 μm, 101±28 μm, and 96±23 μm at 3, 6, 12, and 24 months, respectively. The median best-corrected visual acuity was 0.4 logMAR (range, 0–2 logMAR) at 24 months, demonstrating a significant difference from that before surgery (2 logMAR; range, 0.2–3 logMAR) (T=187.5, P<.001). Partial graft dislocation was the most common postoperative complication, with an occurrence rate of 14% (n=12), and it was associated with an abnormal iris-lens diaphragm (r=.35, P<.001). The other complications included a high intraocular pressure (n=5, 6%), endothelial graft rejection (n=4, 5%), and pupillary block (n=1, 1%). Endothelial graft decompensation occurred in the two eyes, and 98% (n=83) of the grafts survived at 24 months.

Conclusions

Data of the study suggest that the treatment using FLS-DSEK seems to be promising and might be considered a feasible choice in patients with endothelial dysfunction.

Trial registration

1. Date of registration: 2021-02-18

2. Trial registration number: ChiCTR2100044091

3. Registration site: https://www.chictr.org.cn/

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-021-05383-x.

Dye-based identification of the orientation of tissue for Descemet stripping automated endothelial keratoplasty: A laboratory-based study

Purpose:

To describe the features enabling the identification of the orientation of Descemet stripping automated endothelial keratoplasty (DSAEK) lenticule with the assistance of vital dyes.

Methods:

This is a blinded experimental lab-based study, including 30 microkeratome prepared precut DSAEK lenticules. The lenticules were divided into control and study arms which included 10 unstained and 20 stained lenticules, respectively. In the study arm, vital dyes like trypan blue (TB), brilliant blue (BB), indocyanine green (ICG) and fluorescein stain (FS) were used to stain 5 lenticules each. They were examined by experienced (group 1) and novice surgeons (group 2) to identify the correct orientation of the lenticule. The results were tabulated and analyzed.

Results:

Of the 30 lenticules examined, the average of total scores obtained by each observer was higher (78%) in group 1 as compared to group 2 (65.3%) which was statistically significant (P < 0.005). In group 1, the accuracy of identifying the correct orientation of unstained lenticules was 70% which improved to 82% on staining. The accuracy in group 2 was 58% with unstained lenticules which improved to 69% on staining. Within the study arm, irrespective of surgical experience, the accuracy was highest with BB (86%), followed by TB (82%), ICG (72%) and FS (62%).

Conclusion:

This study found that the accuracy of identifying the orientation of DSAEK lenticules increased with experience and with the assistance of staining using vital dyes. This accuracy improved with blue dyes like brilliant blue and trypan blue, irrespective of the level of experience.

Incidence of Ultrathin Descemet Stripping Endothelial Keratoplasty Corneal Graft Rejection following Steroid Discontinuation

Purpose/Aims: To determine the incidence of corneal graft rejection in patients with approximately 1 year of steroid therapy following uDSEK. A shortened course of corticosteroids may be beneficial and a viable option in Ultrathin Descemet's Stripping Endothelial Keratoplasty (uDSEK).Materials and Methods: This retrospective cohort study evaluated corneal graft rejection rate in 170 cases of uDSEK that met inclusion criteria with approximately 1 year of steroid therapy. Corneal graft rejection was defined by anterior chamber cell/flare, keratic precipitates with/without corneal edema, and/or a rejection line. The following were collected retrospectively from January 1, 2005 through January 1, 2013: gender, age, race, indication for uDSEK, length of follow-up, length of steroid therapy. Continuous data were compared using Wilcoxon Rank Sum Test and categorical data were compared using Fisher's Exact Test.Results: The included eyes had an average length of steroid therapy of 431 days (range 85-720 days) with an average follow-up of 1274 days (range 395-3186 days). During the follow-up period without steroid, 5 of the 170 eyes were diagnosed with rejection (2.94%). Of the five eyes that experienced rejection, four eyes resolved after topical prednisone was reinstituted alone and did not require repeat uDSEK. The other eye was lost to follow-up. The cumulative probability of rejection after steroid cessation was calculated at 0.67% after 12 months, 2.20% after 18 months, 3.08% after 24 months, and 4.55% after 36 months.Conclusion: Discontinuation of topical steroid at approximately 1 year after uDSEK results in a low rate of corneal graft rejection and may prove extended use unnecessary.

Refractive outcomes following cataract combined with lamellar keratoplasty: femtosecond-DSEK versus microkeratome-DSAEK

PURPOSE

Prediction of postoperative refraction following posterior lamellar keratoplasty is crucial for choosing proper intraocular lens power in combined surgeries. Femtosecond laser-assisted Descemet stripping endothelial keratoplasty (FS-DSEK) creates thin, planar grafts while microkeratome-assisted Descemet's stripping automated endothelial keratoplasty (DSAEK) creates non-planar, concaved grafts. We evaluated whether this fundamental difference affects the refractive outcomes in cataract surgery combined with FS-DSEK compared to cataract surgery combined with microkeratome-assisted DSAEK.

METHODS

A retrospective analysis of 28 patients who underwent FS-DSEK combined with phacoemulsification and intraocular lens (IOL) implantation (group A) compared to 26 patients who underwent microkeratome-assisted DSAEK combined with phacoemulsification and IOL implantation (group B). Pre- and 1-year postoperative best-corrected visual acuity (BCVA), keratometry values, corneal thickness, central-to-peripheral graft thickness ratio (C/P ratio), and target postoperative spherical equivalent (SE) versus actual postoperative SE were analyzed.

RESULTS

Target postoperative SE and actual postoperative SE significantly shifted toward hyperopia in group B, but not in group A. Postoperative hyperopic shifts were 0.14 D and 1.13 D in groups A and B, respectively (P < 0.001). BCVA improved after surgery in both groups, with no significant difference between the groups. Postoperative C/P ratio differed significantly between the groups and was negatively correlated with postoperative hyperopic shift (r =  - 0.616, P < 0.001).

CONCLUSION

Refractive outcomes of cataract surgery combined with FS-DSEK are relatively neutral, whereas those of cataract surgery combined with microkeratome-assisted DSAEK cause significant hyperopic shift. Clinicians should select accordingly an appropriate intraocular lens power when performing these surgeries.

Standardized pachymetry-assisted manual lamellar dissection for Descemet stripping endothelial keratoplasty

PURPOSE

To present an alternative technique (Pachy-DSEK) for the manual preparation of thin endothelial lamellae in Descemet stripping endothelial keratoplasty (DSEK), as well as to evaluate its visual and anatomic outcomes.

METHODS

A retrospective chart review was conducted in 15 cases who underwent DSEK at a private eye clinic in Brazil (INOB, Brasília) from June 2017 to December 2019. All patients had ocular comorbidities and relative contraindications to Descemet membrane endothelial keratoplasty (DMEK). All endothelial lamellae were manually prepared by using a standardized technique. Best corrected visual acuity (BCVA), tomographic parameters and graft's thickness were evaluated preoperatively and at 6 months. Endothelial cell counts were evaluated preoperatively and at 12 to 24 months.

RESULTS

During preparation there was one case (6%) of peripheral tear and no tissue was lost. At 6 months, the median BCVA improved from 1.60 to 0.40 logMAR (p = 0.0009). There was no significant change in anterior (p = 0.507) and posterior astigmatism (p = 0.483), anterior (p = 0.683) and posterior mean keratometry (p = 0.767), and total corneal power (p = 0.952). The median central graft thickness at 6 months was 80 µm. Ultrathin grafts (<130 µm) were achieved in 80% of cases. At 12 to 24 months endothelial cell count decreased significantly. Graft's detachment occurred in two cases (13%) and endothelial rejection in one case (6%).

CONCLUSION

By using ultrasonic pachymetry intra-operatively and standardizing graft preparation, most manually dissected endothelial lamellae were ultrathin. Pachy-DSEK was safe and effective for treating endothelial disfunction in eyes with ocular comorbidities. It may be a cost-effective alternative to automated dissection methods.

Modified thin manual Descemet stripping endothelial keratoplasty with air-guided, non-pachymetric donor lenticule dissection: outcomes of graft thickness and complication rate

AIM

To describe a modified technique of donor lenticule dissection for thin manual Descemet stripping endothelial keratoplasty (TM-DSEK).

METHODS

Donor material was soaked in balanced salt solution (BSS) for 30min, before being mounted on an artificial anterior chamber (AAC). Rather than BSS, the AAC was filled with filtered air, resulting in a visible reflection at the corneal endothelium-air interface. This reflection served as a landmark for the depth of the dissection, facilitating the creation of a thin lenticule with low risk of perforation. Dissection was commenced at a standardized depth of 500 microns, with no initial pachymetry necessary. Totally 29 donor corneas were dissected by a novice TM-DSEK surgeon. Dissection time, central graft thickness at 2mo and complications were analysed.

RESULTS

Results were similar to other endothelial keratoplasty techniques, despite the cases being performed by a novice DSEK surgeon. Mean dissection time was 7min (range 6-10). One graft perforation occurred (3.45%), but the air tamponaded the break and enabled dissection to be restarted and completed from a different location. Mean central graft thickness after at least two months follow-up was 106 microns (range 25-170).

CONCLUSION

A problem with manual DSEK is the risk of graft perforation by attempting to dissect too thin a lenticule, or creating a thick graft due to fear of perforating. This modified air-guided technique addresses this problem, and is recommended for surgeons either embarking on the learning curve, or who wish to achieve more consistently thin grafts while reducing perforation rates.

Sheets glide-assisted versus Busin glide-assisted insertion techniques for descemet stripping endothelial keratoplasty (DSEK): A comparative analysis

Background

The donor lenticule insertion techniques play a crucial role in outcomes following descemet stripping endothelial keratoplasty (DSEK) and the current study is aimed to compare two of the commonly performed donor lenticule insertion techniques in DSEK.

Method

Descemet stripping endothelial keratoplasty was performed in 48 eyes of 48 patients at two tertiary eye care centers from January 2014 to December 2016. At one center (Group 1), 26 patients had Sheets glide-assisted lenticule insertion whereas at other center (Group 2), 22 patients had Busin glide-assisted insertion of donor lenticule. Best corrected visual acuity (BCVA), manifest spherical equivalent, manifest cylinder, endothelial cell density (ECD) and percentage of endothelial cell loss (ECL) were compared between the two groups at 6 months after DSEK. In addition, intraopertaive and postoperative complications were also compared.

Results

At 6 months after DSEK, an insignificant difference was observed in BCVA [Group 1: 0.48 logarithm of the minimum angle of resolution (log MAR); Group 2: 0.50 log MAR (p = 0.74)], mean manifest spherical equivalent [Group 1: 0.64 diopter (D); Group 2: 0.59 D (p = 0.74)], mean manifest cylinder [Group 1: 1.35 D; Group 2: 1.32 D (p = 0.92)] and mean ECL [Group 1: 26.75%; Group 2: 28.76 (p = 0.44)] between the two groups. In addition, the rate of complications is similar between the two groups.

Conclusions

Both Sheets glide-assisted and Busin glide-assisted donor lenticule insertion techniques are associated with similar surgical outcomes after DSEK.

[Descemet's stripping endothelial keratoplasty (DSAEK) in failed penetrating keratoplasty patients: graft survival rate and its associated factors]

Objective: To explore graft survival rate and its associated factors of DSAEK in patients with endothelial decompensation after penetrating keratoplasty (PKP). Methods: A retrospective case study was conducted, including 51 patients (51 eyes) that underwent DSAEK for endothelial decompensation after PKP in Department of Ophthalmology in Peking University Third Hospital from June 2009 to September 2017. The mean recipient age was (43.3±21.0) years. There were 36 males and 15 females. Data comprising demographic details,surgical methods, complications,follow-up durations,final states of grafts,preoperative and postoperative risk factors were collected. Kaplan-Meier analysis was used to determine the cumulative probability of graft survival. Cox regression model was developed to examine for factors associated with graft survival. Results: Among 51 eyes,the overall graft survival rate was 78%(40/51). The cumulative probability was 85% (95%CI: 0.73-0.96) and 69% (95%CI: 0.52-0.86) at 1 year and 2 years, respectively. The median survival time was 42 months. The diameter of DSAEK graft and postoperative intraocular pressure correlated with the long-term survival of graft. Larger diameter of DSAEK graft was a protective factor for graft survival (HR=0.29, 95%CI: 0.12-0.73), while postoperative high intraocular pressure was a risk factor (HR=1.08, 95%CI: 1.00-1.16, HR=1.10, 95%CI:1.01-1.12). Recipient age, sex, lens status, the number of previous PKPs and previous glaucoma surgery had no significant effect on long-term survival (P>0.05). Conclusions: DSAEK is an effective treatment for endothelial decompensation after PKP,with favorable graft survival rate. Larger diameter of graft is beneficial to the long-term survival,while high postoperative intraocular pressure is a risk factor for graft failure. (Chin J Ophthalmol, 2019, 55: 428-434).

Different graft thicknesses after Descemet stripping endothelial keratoplasty for bullous keratopathy in the two eyes of the same patient

Objective

To describe a very unique case of two Descemet stripping automated endothelial keratoplasty (DSAEK) surgeries performed in both eyes of the same patient with an extremely different graft thickness and overall corneal thickness but with the same corrected distance visual acuity (CDVA) 2 years after surgery.

Case presentation

A 75-year-old woman with bilateral bullous keratopathy (BK) was submitted to DSAEK surgeries in both eyes, first in right and after 6 months in left eye. CDVA was 20/160 in the right eye and 20/63 in the left eye. Corneal thickness evaluated by anterior segment optical coherence tomography was 569 µm in the right eye and 560 µm in the left eye. The root mean square (RMS) was 2.1 in the right and left eyes. Endothelial cell densities were not detectable in both eyes. The estimated precut donor graft thickness from eye bank was 250 and 40 µm in the right and in the left graft, respectively. Two years after surgery CDVA was 20/25 in both eyes. Corneal thickness was 633 µm with a lenticule thickness of 206 µm in the right eye and 439 µm with a lenticule thickness of 48 µm in the left eye. The RMS was 1.7 in the right eye and 1.4 in the left eye. Endothelial cell density was 2.272 cells/mm² in the right and 2.154 cells/mm² in the left eye.

Conclusion

DSAEK was safe and effective in the treatment of BK. In our report, the visual outcome resulted to be poorly related either to donor graft thickness or to postoperative corneal thickness.

POSTOPERATIVE THINNING OF LAMELLAR DONOR GRAFT AFTER CONVENTIONAL DESCEMET'S STRIPPING AUTOMATED ENDOTHELIAL KERATOPLASTY

- The purpose of this study was to evaluate postoperative deturgescence of lamellar donor graft after conventional Descemet's stripping automated endothelial keratoplasty (DSAEK). It was a prospective study that included 55 eyes of patients (mean age 70.9±9.4 years; female 61.8%, male 38.2%). Preoperative thickness of lamella was compared with postoperative thickness six months after surgery. Central lamellar graft thickness decreased from 142±27 µm preoperatively to 124±20 µm 6 months postoperatively (p<0.01). After performing conventional DSAEK corneal transplantation, surgeons should expect deturgescence of corneal graft and reduction in thickness of lamellae by about 12% of initial thickness according to our results. We found this information important for better planning of surgical procedures and knowing what to expect after surgery, as well as for better cooperation with eye banks when ordering pre-cut corneal tissue.

[Pre-descement membrane endothelial keratoplasty for treatment of patients with corneal endothelial decompensation]

Objective: To investigate the clinical outcomes of Pre-descement membrane endothelial keratoplasty (PDEK) for treatment of patients with corneal endothelial decompensation. Methods: Retrospective study of case series. The cases of 20 patients (20 eyes) who were diagnosed with corneal endothelial decompensation induced by various original diseases and received PDEK during July 2016 and December 2016 at Zhongshan Ophthalmic Center have been analyzed. The participants included 8 males and 12 females with an average age of (59.3±11.8) years. All 20 patients received PDEK operation, the Dua's layer, descement membrane and endothelium of donor tissue were separated from the underlying stroma with the application of big-bubble technique, and donor discs with diameters of 7.75 or 8.00 mm were harvested with scissors. The donor discs were stained with 0.06% trypan blue and loaded on inserters which were then gently inserted into the anterior chamber of the recipient. When the rolled inserted graft was unfolded, air was carefully injected into the anterior chamber underneath the graft so that the graft can attach to the stroma of the recipient. Post-operation follow-ups of over 6 months have been conducted for all patients, the best spectacle corrected visual acuity (BSCVA), the position of donor disc, corneal thickness and corneal endothelial cell density (ECD) were documented. The pre-operation and post-operation (6 months postoperatively) corneal thickness data of the patients were analyzed with paired sample t test. Results: The success rate of preparing PDMEK donor disc with big-bubble technique is 90% (18/20). Eighteen patients (90%) received PDMEK surgery successfully. Anterior segment optical coherence tomography (AS-OCT) results indicated that sixteen donor discs (16/18) were well attached to the back surface of the recipient stroma, and that two discs (2/18) dislocated at 6 days after surgery. At 6 months post-operatively, the corneas of 14 patients (14/18) turned clear with their BSCVA ranging 0.4 to 1.0, and the ECD was (1 389.3±373.2) cells/mm(2) for the patients with clear corneas. At 6 months post-operatively, the average corneal thickness of the patients reduced to (605±45) μm from the preoperative level of (655±56) μm, and the differences are of statistical significance (t=2.137, P=0.032). Conclusions: Application of big-bubble technique could effectively secure the success rate of PDEK disc preparation and control the loss of donated corneas. PDEK disc can be easily handled and unrolled in the anterior chamber, which could improve the postoperative clinical outcomes. (Chin J Ophthalmol, 2018, 54: 105-110).

Glaucoma after corneal replacement

Glaucoma is a well-known complication after corneal transplantation surgery. Traditional corneal transplantation surgery, specifically penetrating keratoplasty, has been slowly replaced by the advent of new corneal transplantation procedures: primarily lamellar keratoplasties. There has also been an emergence of keratoprosthesis implants for eyes that are high risk of failure with penetrating keratoplasty. Consequently, there are different rates of glaucoma, pathogenesis, and potential treatment in the form of medical, laser, or surgical therapy.

[Clinical research progress in endothelial keratoplasty]

Endothelial keratoplasty (EK) has gradually replaced penetrating keratoplasty (PKP) and has become the main method for the treatment of endothelial dysfunction in developed countries in recent years. EK is safe and effective and can achieve good postoperative vision. The surgical techniques and postoperative effects have been improved continuously along with the development of microsurgical technology and surgical instruments. The EK surgeries mainly include Descemet stripping endothelial keratoplasty (DSEK), Descemet stripping automated endothelial keratoplasty (DSAEK), Descemet membrane endothelial keratoplasty (DMEK) and ultra-thin Descemet stripping automated endothelial keratoplasty (UT-DSAEK), which have different characteristics and advantages compared with PKP. In this article, the characteristics of different EK surgeries, postoperative effects and related complications in clinical research are reviewed. (Chin J Ophthalmol, 2017, 53: 714-720).

Incidence of cystoid macular edema after Descemet's stripping automated endothelial keratoplasty

AIM

To determine the incidence of cystoid macular edema (CME) after Descemet's stripping automated endothelial keratoplasty (DSAEK).

METHODS

This study included all consecutive patients operated in a Spanish tertiary reference hospital over a period of four years. A total of 55 eyes from 47 patients matched the selection criteria. CME was diagnosed clinically at the slit-lamp and confirmed by optical coherence tomography.

RESULTS

Six cases of CME were diagnosed postoperatively, which represented an incidence of 11%. Three patients had previously undergone DSAEK alone (7%; 3/41) and the other three, DSAEK combined with phacoemulsification (21%; 3/14). Five out of six patients with CME responded to standard therapy.

CONCLUSION

CME is a possible complication after DSAEK and can be treated with standard therapy. CME appears more frequently when DSAEK is combined with phacoemulsification and posterior chamber (PC) intraocular lens (IOL) implantation. Intraoperative damage to the corneal endothelial cells might play a role in the pathogenesis of CME. As long as the causes remain unclear, we recommend administering prophylaxis when risk factors are present or when combined surgery is planned.

[Descemet's membrane endothelial keratoplasty for treatment of patients with corneal endothelial decompensation]

Objective: To evaluate the clinical outcomes of Descemet's membrane endothelial keratoplasty (DMEK) for treatment of patients with corneal endothelial decompensation in China. Methods: Interventional case series. Ten patients (10 eyes) with the diagnosis of corneal endothelial decompensation received DMEK during July 2016 and September 2016 in Zhongshan Ophthalmic Center. Descemet's membrane of the donor tissue was carefully stripped from the underlying stroma manually and cut with a 7.75- or 8.0-mm-diameter donor punch. After stained with 0.06% typan blue, the donor disc loaded on an inserter was gently inserted into the anterior chamber of the recipient. When the rolled graft was unfolded, air was carefully injected into the anterior chamber underneath the graft, so that the graft attached to the stroma of the recipient. All patients were followed up for 3-6 months. The best spectacle corrected visual acuity, the status of donor disc, corneal thickness and corneal endothelial cell density were documented and analyzed. Results: At 1 day after surgery, 1 donor disc presented a rolled edge, and repeated DMEK surgery was performed for this patient. The remaining 9 donor discs presented in place well. At 1 month after surgery, 7 donor discs were found to well attach to the back surface of the recipient stroma with normal corneal posterior surface using anterior segment optical coherence tomography. The average corneal thickness reduced to (620±67) μm from preoperative (680±78.3) μm (t=2.677, P=0.025). At 3 months after surgery, 6 patients achieved clear corneas with best spectacle corrected visual acuity ranging from 0.4 to 0.8. The endothelial cell density was 1 342.3±436.5 (872 to 1 933) cells/mm(2) in the patients with clear corneas. The average corneal thickness reduced to (612±70) μm (t=2.971, P=0.016). Conclusions: DMEK could improve visual acuity for corneal endothelial decompensation, but there were more technical difficulties in Chinese eyes. (Chin J Ophthalmol, 2017, 53: 534-539).

Clinical Outcomes of Descemet Membrane Endothelial Keratoplasty During the Surgeon Learning Curve Versus Descemet Stripping Endothelial Keratoplasty Performed at the Same Time

PURPOSE

To compare outcomes after Descemet Membrane Endothelial Keratoplasty (DMEK) and traditional Descemet Stripping Endothelial Keratoplasty (DSEK) during the surgeon's DMEK learning curve in a prospective, non-randomized, consecutive, interventional case series.

METHODS

Consecutive patients presenting to the university eye clinics and undergoing endothelial keratoplasty were included. Data including patient demographics, visual acuity, endothelial cell counts and complications were recorded at baseline, as well as 3 and 6 months post-operatively. The primary outcome for this study was BSCVA at 6 months. Pre-specified secondary outcomes included endothelial cell counts and complication rates.

RESULTS

A total of 60 eyes of 42 consecutive patients met inclusion criteria, underwent endothelial keratoplasty, and were included in this analysis. Of these, 18 eyes of 14 patients had DSEK while 42 eyes of 28 patients had DMEK. After controlling for baseline visual acuity, study participants undergoing DMEK had a statistically significant approximately half-line improvement in visual acuity compared with DSEK at 3 months (P=0.05) but not at 6 months (P=0.22). DMEK patients experienced an average of 43% endothelial cell loss compared with 25% in DSEK. There were 5 primary graft failures after DMEK compared with 0 after DSEK and but this was not a statistically significant difference (P=0.09).

CONCLUSION

During the surgeon's DMEK learning curve there was some evidence of improved visual acuity outcomes in DMEK. We observed worse 6-month endothelial cell loss among DMEK patients; however this may improve with surgeon experience.

Comparison of Long-term Clinical Outcomes between Descemet's Stripping Automated Endothelial Keratoplasty and Penetrating Keratoplasty in Patients with Bullous Keratopathy

Purpose

To compare 2-year clinical outcomes of Descemet's stripping automated endothelial keratoplasty (DSAEK) and penetrating keratoplasty (PK) in patients with bullous keratopathy.

Methods

A retrospective chart review was performed to obtain 2 years of follow-up data of DSAEK or PK at a single center from March 2009 to September 2012. The study comprised 15 eyes of DSAEK and 11 eyes of PK. Outcome measures included best-corrected visual acuity (BCVA), spherical and keratometric changes, central corneal thickness, endothelial cell density, intraocular pressure, and postoperative complications. Graft survival rate was assessed by Kaplan-Meier survival analysis.

Results

There were no differences in patient baseline characteristics between the two groups. At postoperative 2 years, better BCVA of 0.69 ± 0.51 logarithm of the minimum angle of resolution (logMAR) was found after DSAEK compared to 0.88 ± 0.48 logMAR after PK. Refractive cylinder in DSAEK and PK was −2.60 ± 1.53 and −6.00 ± 1.05 diopters (D), respectively, and keratometric cylinder was 3.27 ± 3.70 and 6.34 ± 3.51 D, respectively, at postoperative 2 years. The difference of mean spherical equivalents between postoperative 1 month and 2 years was 0.84 D after DSAEK and 2.05 D after PK. A hyperopic shift of 1.17 D was present after 2 years of DSAEK. The mean endothelial cell density at postoperative 2 years was 1,548 ± 456 cells/mm² for DSAEK and 1,052 ± 567 cells/mm² for PK, with a cell loss of 19.96% vs. 52.38%, respectively when compared to postoperative 1 month. No significant difference in central corneal thickness was found between DSAEK and PK (592 ± 75 vs. 563 ± 90 µm, respectively). Finally, the 2-year survival rate did not differ significantly between DSAEK and PK (93.3% vs. 81.8%, respectively, p = 0.344).

Conclusions

Compared to PK, DSAEK provided more stable refractive errors with better visual outcome, lower endothelial cell loss, and a lower rate of graft rejection at postoperative 2 years in patients with bullous keratopathy.

[Complications of Descemet Stripping Automated Endothelial Keratoplasty (DSAEK)]

BACKGROUND

Lamellar keratoplasties, e.g. Descemet's stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) are considered the procedures of choice for corneal endothelial diseases. In comparison to penetrating keratoplasty (PK) they are associated with faster visual rehabilitation, a lower risk of complications and a decreased necessity for follow-up visits, which reduces the burden on quality of life in elderly patients. In order to advise patients regarding the indications for surgery and to facilitate the follow-up management, it is important to know the most important complications associated with these keratoplasty techniques.

RESULTS AND DISCUSSION

The most important preoperative complication is a delayed indication for the operation. In contrast to PK, DSAEK and DMEK surgery should be provided at an earlier stage of disease as chronic edema alters the stroma and reduces the speed of visual recovery. The most important complications during or early after surgery are detached lamellae, pupillary blocks with increased pressure or air bubbles in the vitreous cavity in patients with previous vitrectomy. The main long-term complications include chronic increased intraocular pressure and immune-mediated graft rejections in DSAEK patients after reducing or stopping topical corticosteroid therapy. This article describes the potential complications of endothelial keratoplasty and provides a detailed explanation of strategies to avoid these complications.

Evolving Techniques in Corneal Transplantation

Corneal transplantation is one of the most common types of human transplant surgery. By removing a scarred or damaged host cornea and replacing it with a clear and healthy donor transplant, this procedure helps to restore vision in a variety of corneal diseases. The traditional technique for corneal transplantation, penetrating keratoplasty (PKP), involves transplantation of all corneal layers. Over the past decade though, there has been a trend away from PKP as surgeons have developed partial thickness transplant procedures, such as deep anterior lamellar keratoplasty and Descemet stripping automated endothelial keratoplasty. These partial thickness transplant procedures selectively replace diseased host corneal tissue, while conserving healthy and functioning tissue. This review describes current surgical techniques in the field of corneal transplantation, with special emphasis on indications for transplantation and postoperative outcomes.

A comparison of posterior lamellar keratoplasty modalities: DLEK vs. DSEK

Purpose

To compare clinical outcomes after deep lamellar endothelial keratoplasty (DLEK) with Descemet stripping endothelial keratoplasty (DSEK) performed as initial cases by a single surgeon.

Methods

Sixteen patients with corneal endothelial were enrolled. Eight patients (8 eyes) underwent DLEK and 8 patients (8 eyes) DSEK. We measured uncorrected visual acuity, best corrected visual acuity (BCVA), manifest refraction, corneal endothelial count, interface opacity via Schiempflug imaging, and contrast sensitivity, as well as tracked postoperative complications over the first postoperative year.

Results

Primary graft failure occurred in two DLEK cases and one DSEK case, all of which were excluded for further analysis. The average 12-month postoperative BCVA was 20/70 in the DLEK group and 20/50 in the DSEK group, with the difference not statistically significant. No significant differences were identified between the 2 groups in terms of mean spherical equivalent and refractive astigmatism, although individuals in the DSEK group tended toward hyperopia. The average endothelial cell count at postoperative month 12 was 1849±494 in the DLEK group and 1643±417 cells/mm² in the DSEK group, representing cell losses of 26.2% and 31.9%, respectively. No significant differences in endothelial cell count or endothelial cell loss were observed between groups. Early postoperative donor disc dislocation occurred in two eyes after DLEK and one eye after DSEK. Interface opacities and contrast sensitivities were similarly not significantly different between groups.

Conclusions

No significant differences in any assessed clinical outcome were observed between individuals undergoing DLEK and DSEK, when performed as initial cases by a single surgeon.