How Much Progress Has Been Made in Corneal Transplantation?

Determinants of Glaucoma Therapy Escalation After Descemet-Stripping Automated Endothelial Keratoplasty To Treat Pseudophakic Bullous Keratopathy: A Nested Case-Control Study

Purpose:

To study the determinants of glaucoma therapy escalation (GTE) after Descemet-stripping automated endothelial keratoplasty (DSAEK) for pseudophakic bullous keratopathy in an eye-care hospital in Saudi Arabia.

Methods:

This nested case-control study evaluated patients who required medical or surgical treatment for controlling glaucoma after DSAEK (defined as GTE; GTE group). A group of patients who did not require any intervention post-DSAEK served as controls (control group). Data were collected on preoperative, intraoperative, and postoperative parameters for DSAEK. Variables were compared between groups to evaluate risk factors for GTE and graft failure.

Results:

The study sample comprised 117 eyes (40 in the GTE group and 77 in the control group). Glaucoma was present in 20 (17.1%) of the eyes before DSAEK. The median duration of follow-up was 27 months [Interquartile range (IQR): 24; 42]. Intraoperative complications occurred in 4 eyes, and 2 eyes had a decentered donor button. Graft failure causing vision impairment and GTE at the final follow-up were noted in 19 (16.2%) and 40 (34.2%) eyes, respectively. Glaucoma prior to DSAEK was significantly associated with GTE [odds ratio (OR) = 6.4; 95% confidence interval (CI) 2.4; 18.3; P = 0.0004]. A history of penetrating keratoplasty (PK) was significantly associated with GTE after DSAEK [OR = 6.2 (95% CI 1.5; 24.7) P = 0.008]. At the last visit, GTE and graft failure were positively associated (OR = 27.2, P < 0.005).

Conclusion:

Escalation of glaucoma therapy was warranted in one in 3 eyes that had undergone DSAEK. GTE and graft failure are interrelated complications. Patients with glaucoma and PK have a higher risk of GTE post-DSAEK.

Trends in surgical procedures and indications for corneal transplantation over 27 years in a tertiary hospital in Japan

PURPOSE

To characterize trends in procedures, and indications for corneal transplantation over 27 years in a single referral center in Japan.

STUDY DESIGN

Retrospective study.

METHODS

Data from a consecutive series of corneal transplant surgery cases performed from 1991 to 2017at Ichikawa General Hospital were collected. The surgical procedures, indications, and causes of corneal endothelial dysfunction were evaluated.

RESULTS

Among 6,025 transplantations, a total of 3,991 cases underwent penetrating keratoplasty (PKP), 1009 underwent (deep) anterior lamellar keratoplasty, 746 underwent endothelial keratoplasty, and 309 underwent epithelial transplantation. Over that period the frequency of PKP decreased, whereas the frequency of lamellar keratoplasty increased. The four major surgical indications were bullous keratoplasty (BK 30.0%), regraft (24.2%), post-keratitis scars (17.1%), and keratoconus (11.4%). After dividing the study period into four time periods, we found that BK and regraft increased (from 20.3% to 34.5% and 18.2% to 31.1%, respectively), whereas post-keratitis scars and keratoconus decreased (from 26.0% to 9.5% and 14.1% to 7.2%, respectively) between the first and last period. Pseudophakic or aphakic BK were the major causes of corneal endothelial dysfunction until 2010. Cases of laser-iridotomy-induced BK peaked in 35 eyes (34.3% of BK) in 2000 and declined after 2013. Cases of Fuchs endothelial corneal dystrophy increased from 0 in 1991, to 15 eyes (18.5% of BK) in 2017.

CONCLUSION

Lamellar keratoplasty has replaced PKP in our hospital. BK and regraft have increased, whereas post-keratitis scars and keratoconus have decreased. Laser-iridotomy-induced BK has decreased during the past decade, whereas Fuchs endothelial corneal dystrophy has increased.

A 5-year analysis of endothelial vs penetrating keratoplasty graft survival in Chinese patients

AIM

To determine if there is any difference in long term graft survival between Descemet's stripping endothelial keratoplasty (DSEK) and penetrating keratoplasty (PK).

METHODS

A retrospective 5-year cases analysis of bullous keratopathy secondary to Fuchs' endothelial dystrophy or pseudophakic bullous keratopathy, receiving either DSEK or PK. A total of 42 DSEK cases and 25 PK cases were included in the analysis.

RESULTS

In the 5-year analysis, graft survival rates were very similar in the two groups (DSEK 77.1% vs PK 76.0%, P=0.918, 95%CI: -6.3 to 33.4). Sub-analyses at 1y (DSEK 81% vs PK 95%, P=0.085, 95%CI: -29 to 3.6) and 2y (DSEK 81% vs PK 88%, P=0.381, 95%CI: -25.9 to 11.8) show a trend towards lower survival rates of DSEK vs PK, but the results were not statistically significant.

CONCLUSION

Long term 5-year graft survival is similar between the DSEK and PK methods of corneal transplant in Chinese patients with bullous keratopathy.

Overexpression of MMPs in Corneas Requiring Penetrating and Deep Anterior Lamellar Keratoplasty

Purpose

Matrix metalloproteinases (MMPs) comprise a family of zinc-dependent endopeptidases involved in wound healing processes, including neovascularization and fibrosis. We assessed MMP protein expression levels in diseased corneas of patients requiring penetrating and deep anterior lamellar keratoplasty. The purpose of this study was to test the hypothesis that upregulation of MMPs in diseased corneas is positively associated with clinical levels of corneal neovascularization and fibrosis.

Methods

Protein expression levels of nine individual MMPs were quantified simultaneously in human corneal lysates by using the Bio-Plex Pro Human MMP 9-Plex Panel and the MAGPIX technology. Measurements of MMP1, MMP2, MMP3, MMP7, MMP8, MMP9, MMP10, MMP12, and MMP13 were performed on diseased specimens from 21 patients undergoing corneal transplantation (17 for penetrating keratoplasty and 4 for deep anterior lamellar keratoplasty) and 6 normal control corneas.

Results

Luminex-based expression analysis revealed a significant overexpression of four of the nine MMPs tested (MMP2, MMP8, MMP12, and MMP13) in patient samples compared to control. Significant overexpression of MMP1, MMP2, MMP8, MMP12, and MMP13 was observed in diseased corneas with neovascularization compared with diseased corneas without neovascularization. Overexpression of MMP1, MMP2, MMP8, MMP12, and MMP13 also corresponded with the levels of corneal fibrosis. Finally, reduced expression of MMP3 was detected in keratoconus patients.

Conclusions

Multiple MMPs are expressed in the corneas of patients with chronic disease requiring keratoplasty even when the pathologic process appears to be clinically inactive. In particular, the expression of several MMPs (MMP2, MMP8, MMP12, and MMP13) is positively associated with increased levels corneal fibrosis and neovascularization.

Graft survival rate of deep anterior lamellar keratoplasty for keratoconus: A meta-analysis

BACKGROUND

Deep anterior lamellar keratoplasty (DALK) is an optional treatment for patients with keratoconus, and the associated graft survival rate varies. Herein, we aimed to explore the graft survival rate of DALK in patients with keratoconus.

METHODS

PubMed, Web of Science, and ProQuest databases were searched to retrieve the related articles. General data, clinical characters, and graft survival rates were obtained directly from the included studies and analyzed by meta-analysis.

RESULTS

A total of 12 articles were included. The merged 1-, 3-, and 5-year graft survival rates were 100% (99.9-100%, P < .001), 92.9% (89.8-95.9%, P < .001), and 90.4% (86.0-0.948%, P < .001), respectively. Lower heterogeneity was shown in each subgroup that was divided neither according to the sample number nor number of surgeons.

CONCLUSION

The survival rate slightly decreases year by year, but the overall trend seems relatively stable. Ensuring that all DALK procedures are performed by a single surgeon might be helpful to improve the graft survival rate after surgery.

Factors Limiting the Visual Outcome After Descemet Stripping Automated Endothelial Keratoplasty: Comprehensive Analysis Including the Graft Position and Irregularity

PURPOSE

To investigate factors affecting best postoperative corrected distance visual acuity (CDVA) in patients who have undergone Descemet stripping automated endothelial keratoplasty (DSAEK).

METHODS

Forty-two eyes of 42 patients with predominantly non-Fuchs endothelial corneal dystrophy after DSAEK were retrospectively evaluated. All patients were examined using anterior segment optical coherence tomography when their best postoperative CDVA had been achieved. We analyzed the relationship between best postoperative CDVA and preoperative, intraoperative, and postoperative factors, including corneal higher-order aberrations (HOAs), corneal backward scattering, graft irregularity, and graft decentration. Variables with P < 0.2 in univariate analysis were entered into a multivariate linear regression model to determine the factors affecting best postoperative CDVA.

RESULTS

Mean CDVA improved from 1.16 ± 0.46 preoperatively to 0.22 ± 0.19 logarithm of the minimum angle of resolution equivalents postoperatively (P < 0.0001). Best postoperative CDVA was achieved 11.6 ± 7.7 months after DSAEK. Multivariate analysis showed that anterior corneal coma-like HOAs and venting incisions inside the pupil area were significantly correlated with best postoperative CDVA (t = 2.90, P = 0.006; t = 2.62, P = 0.01, respectively). No significant relationship was found between the visual outcome and any other factor, including posterior corneal HOAs, corneal backward scattering, graft decentration, and graft irregularity.

CONCLUSIONS

Irregularity of the anterior corneal surface and venting incisions inside the pupil area are important factors that impair best postoperative CDVA in patients who have undergone DSAEK. In contrast, our results indicate that the graft position and irregularity might not have a strong influence on the visual outcome after DSAEK.

[Novel concepts for treatment of the corneal endothelium with nanoparticles]

BACKGROUND

The number of corneal transplantations has increased in Germany in recent years. One reason is an earlier time point of surgery due to less invasive posterior lamellar grafting techniques. To date, penetrating and lamellar corneal transplantations are the only established therapeutic options to treat corneal diseases resulting from endothelial cell pathologies.

AIM

This review article provides an insight into nanoparticle-related translational strategies to improve or to avoid corneal transplantation.

RESULTS

Nanoparticle-based strategies for optimization of the corneal endothelium have different fields of application: 1. during donor cornea cultivation in culture medium, 2. for single cell injection therapies and 3. to treat the patients' own endothelium in an effort to avoid transplantation.

CONCLUSION

Several translational concepts exist to improve or to avoid grafting of a donor cornea. The coming decade will provide established alternatives to conventional corneal transplantation.

Light scattering measurements in electron-beam sterilized corneas stored in recombinant human serum albumin

Irradiated corneal tissues have been used for a variety of ophthalmic procedures including glaucoma drainage device covers and lamellar grafts. The maintenance of corneal clarity is important, as light obstructions resulting from processing or long-term storage of irradiated corneas may negatively affect vision and postoperative cosmesis. It has been reported that corneal tissues can be preserved in human serum albumin (HSA), however, the clarity of corneas after long-term storage in HSA has not been well described. Furthermore, the use of donor-pooled serum increases the risk for transmission of blood-borne diseases and may induce an immune response in the recipient. Here, we examined changes in corneal clarity due to electron-beam (e-beam) irradiation and storage in a recombinant human serum albumin (rHSA). Dark-field microscopy was employed to examine the light scattering effects of fresh and irradiated corneas. Compared to measurements taken prior to tissue preparation and e-beam treatment, irradiated corneas showed an average 2.6% increase in light scattering (P = 0.002). Irradiated corneas stored in rHSA at room-temperature for 20 months showed an average increase of 11.6% light scattering compared to fresh corneas (P ≪ 0.01), but did not negatively affect the visualization of printed text, and were deemed suitable for transplant use. Therefore, the slight increase in cornea light scattering, and resulting reduction in corneal clarity, after e-beam treatment and long-term storage in rHSA may not be clinically significant. These results suggest that e-beam sterilized corneal grafts may be used as an alternative to fresh tissue for certain ophthalmic applications.