Trends in the indications for penetrating keratoplasty in the midwestern United States

Comparison of Femtosecond Laser Assistance and Manual Trephination in Deep Anterior Lamellar Keratoplasty in the Treatment of Keratoconus: A Meta-Analysis

PURPOSE

To compare the efficacy and safety of femtosecond laser-assisted deep anterior lamellar keratoplasty (F-DALK) with those of manual-trephination DALK (M-DALK) in treating keratoconus.

DESIGN

Systematic review and meta-analysis.

METHODS

Through November 2022, we comprehensively searched PubMed, EMBASE, the Cochrane Library, and 4 Chinese databases. Studies that involved comparisons between F-DALK and M-DALK groups and that reported on relevant efficacy and/or safety parameters were included. Primary outcomes were uncorrected- and corrected-distance visual acuity and intraoperative complication rates. Secondary outcomes were spherical equivalent, topographic astigmatism, refractive cylinder, mean keratometry, endothelial cell density, suture removal time, and postoperative complication rates. These data were analyzed using Cochrane Review Manager software version 5.3.

RESULTS

This meta-analysis included 9 nonrandomized controlled studies involving 1713 eyes. In eyes treated with F-DALK, corrected-distance visual acuity at 1 to 6 months (weighted mean difference = -0.07 [95% confidence interval {CI} -0.10 to -0.03]; I2 = 0%; P < .001) after surgery was better and intraoperative Descemet membrane perforation occurred less often (odds ratio = 0.53 [95% CI 0.31-0.92]; I2 = 6%; P = .02) than in eyes treated with M-DALK. No clinically significant differences in other outcomes were found among the groups.

CONCLUSIONS

Both F-DALK and M-DALK are safe and efficacious for patients with keratoconus. Compared with M-DALK, F-DALK can provide better early visual acuity and reduce the intraoperative perforation rate, and its likely improvements to long-term visual quality and endothelial cell preservation warrant further investigation. In addition, the 2 techniques seem to be comparable regarding refractive outcomes and other complications.

Incidence of wound dehiscence after keratoplasty: a meta-analysis of observational studies

Background

The comprehensive investigation of the association between keratoplasty and wound dehiscence remains limited, despite corneal disease being a leading cause of visual impairment.

Methods

A meticulous search strategy was executed across prominent databases such as Web of Science, PubMed, Cochrane Library, and Embase. Data relevant to our research objective were extracted from eligible studies. The methodological quality of each study was assessed using the ROBINS-I tool, while statistical analysis was conducted utilizing STATA 17.0. To evaluate potential publication bias, the Funnel plot and Egger's test were employed.

Results

A total of 11 articles were deemed suitable for inclusion in our analysis. Our findings indicate that the overall incidence of wound dehiscence following keratoplasty was estimated to be 1.9% (95% CI: 0.013, 0.026), although substantial heterogeneity was observed (I2 = 72.798%). Notably, developed countries exhibited a higher incidence of wound dehiscence compared to their developing counterparts. Furthermore, the occurrence of wound dehiscence was found to be lower in deep anterior lamellar keratoplasty (DALK) procedures when compared to penetrating keratoplasty (PK). Analysis utilizing Egger's linear regression method yielded no evidence of publication bias (p = 0.91). Moreover, within the first year post-keratoplasty, approximately 31.4% of patients experienced wound dehiscence (95% CI: 0.149, 0.503), and 43.1% exhibited a decline in best-corrected visual acuity (BCVA) (95% CI, 0.341, 0.522).

Conclusion

The results of our study unveiled the occurrence rate of wound dehiscence following keratoplasty, exhibiting variations based on economic level and the specific surgical procedure employed. Furthermore, onset time of wound dehiscence and visual acuity warrant consideration.

Rescuing cellular function in Fuchs endothelial corneal dystrophy by healthy exogenous mitochondrial internalization

Fuchs endothelial corneal dystrophy (FECD) is characterized by an accelerated loss of corneal endothelial cells. Since the function of these cells is to maintain the cornea in a state of deturgescence necessary for its transparency, the depletion of corneal endothelial cells ultimately causes corneal edema and irreversible loss of vision. Evidence is accumulating regarding the central involvement of mitochondria in FECD. As we have previously shown, when endothelial cells die and are not replaced, the mitochondria of surviving cells must provide more energy to compensate, leading to a phenomenon we have called mitochondrial burnout. This burnout causes cell death, thus exacerbating an irreversible vicious circle responsible for FECD progression. Corneal transplantation, for which the transplant supply is insufficient, is the only curative alternative for FECD. It thus becomes imperative to find other avenues of treatment. In this article, we tested whether incorporating healthy mitochondria into FECD cells would improve pathological molecular markers of the disease. Using corneal endothelium explants from FECD patients, we demonstrated that incorporation of exogenous mitochondria into FECD cells by co-incubation reduces oxidative stress, increases mitochondrial membrane potential, and reduces mitophagy. In addition, internalization of exogenous mitochondria significantly reduces apoptosis (57% in FECD vs 12% in FECD with internalized mitochondria). Taken together, these results suggest that the internalization of exogenous mitochondria reverses the vicious circle involved in FECD, thus revealing a much-needed novel treatment alternative for FECD.

Penetrating Keratoplasty: Indications and Graft Survival by Geographic Region

Corneal transplantation, or penetrating keratoplasty (PK), is the most common form of solid-organ transplantation performed worldwide. Here, we evaluated the indications for PK and rates of transplant survival around the world by geographic region. We conducted a literature search of PubMed, MEDLINE, and Google Scholar databases and identified 155 relevant studies from 41 countries published between 1987 and 2021. The most common indications for PK were keratoconus in Europe, Africa, the Middle East, Australia, New Zealand, and Central and South America, bullous keratopathy in North America, and corneal scarring in Asia. The overall global mean graft survival rates at 1-, 2-, 3-, 5-, and 10-years were 88.6%, 81.2%, 78.9%, 72.8%, and 61.2%, respectively. Through this systematic analysis of PK by region, we hope to bring a new perspective to the corneal transplantation literature and to potentially highlight global differences and unmet needs in patient care.

New perspectives in keratoconus treatment: an update on iontophoresis-assisted corneal collagen crosslinking

Keratoconus is a bilateral, asymmetric and progressive corneal disease. It usually results in apical thinning and steepening with corneal deformation and impaired vision. Since the early 1990 s, corneal collagen crosslinking (CXL) has remained the primary treatment to stabilize the progression of the disease. Iontophoresis-assisted CXL (I-CXL) has been proposed as a non-invasive alternative to standard epithelium-off technique, showing promising results. In this article, we review up to date literature to provide state of art knowledge and future perspectives of I-CXL.

Clinical Characteristics and Outcomes of Short-term Repeat Corneal Transplantation

PURPOSE

To explore the primary indications, direct causes and graft survival of short-term repeat keratoplasty.

METHODS

An analytical cross-sectional study.

RESULTS

The primary indications for keratoplasty were infectious keratitis (67.9%) and immune keratopathy (12.8%). The direct causes of graft failure were infectious ulcer (43.6%) and recurrence (30.8%). Pre-operative hypopyon (P = 0.017, HR = 1.757) and use of decellularized porcine corneas as grafts (P = 0.005, HR = 2.690) were independent risk factors for graft failure. The Kaplan-Meier analysis revealed that the 1-year survival rate of 88 repeat grafts was 85.2%, and the 5-year survival rate was 79.2%. The survival rates of the repeat grafts were significantly higher than those of the first grafts (P < 0.001).

CONCLUSION

Infectious keratitis is the most common indication of short-term graft failure and is often failed by infectious ulcer and keratitis recurrence. While the decellularized porcine cornea is a promising application in developing countries, certain difficulties, such as graft melting, remain unresolved.

Changing trends in penetrating keratoplasty indications at a tertiary eye care center in Budapest, Hungary between 2006 and 2017

AIM

To analyze the changing trends in penetrating keratoplasty (PKP) indications.

METHODS

This retrospective study included all patients with PKP between 2006 and 2017. Patients were classified using histological diagnoses. Our groups were as the following: pseudophakic or aphakic bullous keratopathy, regraft, acute necrotizing and ulcerative keratitis, keratoconus, Fuchs' dystrophy, corneal dystrophy other than Fuchs', corneal scar, other diagnoses and failed endothelial keratoplasty graft. Additionally, two different time-periods (2006-2012 and 2013-2017) were analysed.

RESULTS

Totally 1721 histological analyses of 1214 patients were available for review. The diagnoses were pseudophakic or aphakic bullous keratopathy in 487 (28.3%), regraft in 443 (25.7%), acute necrotizing and ulcerative keratitis in 313 (18.2%), corneal scar in 153 (8.9%), keratoconus in 140 (8.1%). Fuchs' dystrophy in 61 (3.5%), corneal dystrophy other than Fuchs' in 46 (2.7%), other diagnoses in 44 (2.6%) and failed endothelial keratoplasty graft in 34 (2.0%) cases. From the first to the second analysed time-period, incidence of acute necrotizing and ulcerative keratitis, corneal scar, Fuchs' dystrophy increased (P≤0.032 for all) and incidence of keratoconus significantly decreased (P=0.015).

CONCLUSION

Pseudophakic or aphakic bullous keratopathy is the leading indication for PKP, followed by regraft and acute necrotizing and ulcerative keratitis.

A 27-Year Report from the Central Eye Bank of Iran

Purpose

To report the 27-year statistical data from the Central Eye Bank of Iran (CEBI) and its activity.

Methods

All CEBI records regarding procured eyes, tissue utilizations, corneal transplants per capita, and indications for keratoplasty from 1991 to 2017 were analyzed.

Results

In total, 115,743 whole eyes were donated during the 27-year period. Out of the 114,169 eyes donated between 1994 and 2017, 95,314 eyes were distributed for transplantation, and 95,057 corneas were actually transplanted. The mean annual rate of corneal transplants per capita was 55.10 - 6 ± 27.10 - 6 . Although penetrating keratoplasty (PKP, 70%) was the most common technique of corneal transplantation during the study period, it exhibited a decreasing trend between 2006 and 2017 (P = 0.048). It was in contrast to Descemet stripping automated endothelial keratoplasty (DSAEK) that demonstrated an increasing trend during the same period (P < 0.001). Keratoconus (KCN, 39.70%) was the most leading indication for keratoplasty over the last three decades followed by bullous keratopathy (BK, 18.5%), corneal scar and opacities (15.7%), and graft failure (GF, 7.5%), with an increasing trend for BK, GF, and KCN. A majority of scleral tissues (83.7%) were utilized for orbital implant protection.

Conclusion

An increasing trend in the number of procured eyes was observed over the past 27 years in Iran. The most leading indications for corneal transplantation were KCN and BK. While PKP was the most common keratoplasty technique, DSAEK showed an increasing trend over the last 12 years.

Chronology of cellular events related to mitochondrial burnout leading to cell death in Fuchs endothelial corneal dystrophy

Fuchs endothelial corneal dystrophy (FECD) is a degenerative eye disease characterized by corneal endothelial cell (CEC) death and the formation of guttae, an abnormal thickening of CEC’s basement membrane. At the tissue level, an oxidative stress causing mitochondrial damage and CEC death have been described to explain FECD pathogenesis. At the cellular level, our group has previously observed significant variability in the mitochondrial mass of FECD CECs. This led us to hypothesize that mitochondrial mass variability might play a key role in the chronology of events eventually leading to CEC death in FECD. We thus used different fluorescent markers to assess mitochondrial health and functionality as a function of mitochondrial mass in FECD corneal endothelial explants, namely, intra-mitochondrial calcium, mitochondrial membrane potential, oxidation level and apoptosis. This has led us to describe for the first time a sequence of events leading to what we referred to as a mitochondrial burnout, and which goes as follow. FECD CECs initially compensate for endothelial cell losses by incorporating mitochondrial calcium to help generating more ATP, but this leads to increased oxidation. CECs then resist the sustained need for more ATP by increasing their mitochondrial mass, mitochondrial calcium and mitochondrial membrane potential. At this stage, CECs reach their maximum capacity and start to cope with irreversible oxidative damage, which leads to mitochondrial burnout. This burnout is accompanied by a dissipation of the membrane potential and a release of mitochondrial calcium, which in turn leads to cell death by apoptosis.

Changing Trends in Penetrating Keratoplasty Indications between 2011 and 2018 - Histopathology of 2123 Corneal Buttons in a Single Center in Germany

Purpose: To analyse the changing trends in penetrating keratoplasty indications between January 2011 and December 2018, at the Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar, Germany. Patients and Methods: This is a retrospective review of 2123 corneal buttons of 1776 patients (1993 eyes, 56.0% males, age at the time of surgery 57.6 ± 18.7 years), who underwent penetrating keratoplasty (PKP) between January 2011 and December 2018. The classification was performed based on histological analysis and using the priority scheme of Brady et al., supplemented by a group of "failed endothelial keratoplasty grafts". Our groups were the following: pseudophakic or aphakic bullous keratopathy, regraft, failed endothelial keratoplasty graft, acute necrotizing and ulcerative keratitis, keratoconus, Fuchs' dystrophy, corneal dystrophy other than Fuchs', corneal scars and other diagnoses. Results: Between 2011 and 2018, keratoconus was the leading indication for PKP in 455 (21.5%) cases, followed by acute necrotizing and ulcerative keratitis in 384 (18.1%), regraft in 367 (17.3%), corneal scars in 350 (16.5%), pseudophakic or aphakic bullous keratopathy in 225 (10.6%), Fuchs' dystrophy in 194 (9.1%), other diagnoses in 64 (3.0%), corneal dystrophy other than Fuchs' in 52 (2.4%), and failed endothelial keratoplasty graft in 32 (1.5%) cases. Conclusions: With the introduction of posterior lamellar keratoplasty, keratoconus remains the leading PKP indication in our center with excimer laser-trephination on a routine basis. A trend towards increasing numbers can be observed regarding acute necrotizing and ulcerative keratitis patients and regrafts. However, the incidence of Fuchs' dystrophy decreased dramatically within PKP patients, with the introduction of posterior lamellar keratoplasty.

Proposed risk factors for failure of transplanted eye bank-prepared descemet stripping automated endothelial keratoplasty tissues

To investigate the possible risk factors for failure of transplanted eye bank-prepared Descemet stripping automated endothelial keratoplasty (DSAEK) tissues. In a retrospective study between March 2011 and March 2019, all the failed DSAEK cases (131 cases) reported to the Central Eye Bank of Iran were compared with a surgeon-matched successful DSAEK group (control, 126 cases) in terms of the donor, DSAEK tissue, and recipient characteristics. Univariate analysis indicated that the DSAEK tissue preparation from excised corneoscleral tissues (OR 2.17; P = 0.026) and donor conjunctival hyperemia (OR 1.62; P = 0.042) were more common in the re-DSAEK group than in the controls. Other donor and recipient characteristics as well as other DSAEK tissue criteria were not significantly different between the re-DSAEK and control groups. DSAEK lenticules in both re-DSAEK and control groups demonstrated symmetric contours. Subgroup analyses in the re-DSAEK group revealed a higher rate of surgeons' low to moderate experience in comparison to those of high experience (P < 0.001). Additionally, failed DSAEK was observed more commonly in donors aged over 50 years than among those under 30 years (P < 0.001). Our study showed that DSAEK tissues prepared from excised corneoscleral tissues and from donors with conjunctival hyperemia were associated with higher rates of re-DSAEK due to failed DSAEK. An increasing trend of re-DSAEK was observed with shorter surgeons' experience and more advanced donor's age.

[Ipsilateral automated anterior lamellar rotational autokeratoplasty in the treatment of superficial central stromal opacity]

Corneal opacity is one of the main causes of monocular blindness in the world. Various modifications of keratoplasty are considered radical, effective - and in some cases the only - way of visual rehabilitation of this category of patients. The article describes a case of using the original surgical method of ipsilateral automated anterior lamellar rotational autokeratoplasty. Application of the described surgical technique made it possible to preserve the advantages of the known methods of ipsilateral rotational penetrating autokeratoplasty (IRA) and to level out their main disadvantages. In addition, the use of anterior lamellar rotational autokeratoplasty allowed the endothelial layer of the cornea to remain intact; its decompensation is one of the main reasons for unsatisfactory outcomes of penetrating keratoplasty. The use of a microkeratome device and the formation of an interface between the layers of its own tissues made it possible to achieve clinically insignificant violation of light scattering in this zone. With the right choice of a patient with shallow local central corneal opacity and careful planning of the original method, ipsilateral lamellar rotational automated autokeratoplasty can be an alternative to both standard penetrating and lamellar allokeratoplasty.

TCF4 and COL8A2 Gene Polymorphism Screening in a Greek Population of Late-onset Fuchs Endothelial Corneal Dystrophy

BACKGROUND/AIM

Fuchs' endothelial corneal dystrophy (FECD) is a hereditary, progressive, bilateral, and irreversible disorder of the corneal endothelium. The purpose of this study was to develop a novel, accurate and high-throughput real-time polymerase chain reaction (PCR) method and melting-curve analysis in order to genotype the rs613872 polymorphism in the transcription factor 4 (TCF4) gene and to implement it on a well-ascertained sample of 22 Greek FECD patients and 58 healthy individuals, age- and sex-matched.

PATIENTS AND METHODS

DNA was extracted from blood samples, which were screened with the DNA sequencing method in order to detect the g.31753T>G/p.L450W (rs8035192) and g.31767C>A/p.Q455K (rs8035191) mutations in a COL8A2 genomic region.

RESULTS

TCF4 risk G allele frequency increased to 48% in FECD patients compared to 17% in healthy-subjects [OR=4.82 (95% CI=1.98-11.73)]. No p.L450W and p.Q455K COL8A2 gene mutations were detected.

CONCLUSION

We confirmed that rs613872 in the TCF4 gene is strongly and statistically associated with late-onset FECD in a Greek population.

Changing indications and surgical techniques for keratoplasty during a 16-year period (2003-2018) at a tertiary referral hospital in Japan

Purpose

To present the changing indications and surgical techniques for keratoplasty during a 16-year period (2003–2018) at a tertiary referral hospital in Japan.

Methods

Consecutive keratoplasty cases at Kanazawa University Hospital from January 2003 to December 2018 were retrospectively reviewed. Keratoplasty procedures included penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), anterior lamellar keratoplasty (ALK), Descemet’s stripping automated endothelial keratoplasty (DSAEK), and Descemet’s membrane endothelial keratoplasty (DMEK). Annual numbers and types of keratoplasty as well as underlying diseases for PK and total keratoplasty procedures were recorded, and annual trends were statistically analyzed using Cochran–Armitage test for trend.

Results

A total of 801 keratoplasty procedures (PK, 319 cases; DALK, 57 cases; ALK, 9 cases; DSAEK, 371 cases; and DMEK 45 cases; mean age, 66.9±16.3 years) were performed for 595 patients (302 males [329 eyes, 419 cases], 293 females [345 eyes, 382 cases]) during the 16-year period. The proportion of PK procedures decreased significantly in the beginning and showed a slightly increasing trend after a plateau around 2015. DSAEK was increasing after 2006 and reached a plateau around 2012. Among 10 underlying diseases for total keratoplasty, corneal opacity and dermoid were decreasing linearly. Failed PK and failed DSAEK were increasing linearly in the beginning and reached a plateau followed by a decreasing trend. In terms of the underlying disease for PK, bullous keratopathy was decreasing in the beginning and reached a plateau around 2015. A total of 19 PK procedures were performed on cases with recalcitrant bullous kerstopathy (BK) after 2010.

Conclusion

The distribution of keratoplasty procedures and underlying diseases changed significantly over 16 years at a tertiary referral hospital in Japan. PK procedure was significantly decreased and DSAEK procedure was significantly increased. PK for BK decreased significantly; however, PK remains a viable option for other recalcitrant corneal diseases.

Indications and Surgical Techniques for Corneal Transplantation at a Tertiary Referral Center

Purpose

The study aimed to review the indications and techniques for corneal transplantation at a tertiary referral center over a 5-year period.

Methods

Records of patients who underwent corneal transplantation at Khalili Medical Center, Shiraz, Iran from September, 2012 to September, 2017 were reviewed.

Results

A total of 1149 eyes of 956 patients underwent corneal transplantation. The most common indication was infectious corneal ulcers (n = 296, 25.8%), followed by keratoconus (n = 243, 21.1%), bullous keratopathy (n = 219, 19.1%), failed grafts (n = 117, 10.2%), non-herpetic corneal scars (n = 113, 9.8%), corneal stromal dystrophies (n = 33, 2.9%), pellucid marginal degeneration (n = 31, 2.7%), and trauma (n = 26, 2.3%); other indications included thin descemetocele, post-herpetic corneal scar, endothelial corneal dystrophies, anterior segment dysgenesis, corneal ectasia after laser in situ keratomileusis, and corneal fibrosis. Corneal transplantation techniques included penetrating keratoplasty (PKP, n = 789, 68.7%), deep anterior lamellar keratoplasty (DALK, n = 187, 16.3%), Descemet's stripping automated endothelial keratoplasty (n = 171, 14.9%), and keratolimbal allograft (n = 2, 0.1%) in descending order. In children (aged ≤18 years), the most common indication was keratoconus (n = 32, 41.6%), and the most common technique was PKP (n = 50, 64.9%). In patients aged 19-27 years, the most common indication was keratoconus (n = 89, 64.5%), and the most common technique was PKP (n = 75, 54.4%).

Conclusion

Infectious corneal ulcer was the most common indication, and PKP was the most prevalent technique in patients undergoing corneal transplantation. DALK was an emerging alternative surgical treatment in patients with corneal disorders in which corneal endothelium is spared.

Improving precision for detecting change in the shape of the cornea in patients with keratoconus

To investigate a method for precision analysis to discriminate true corneal change from measurement imprecision in keratoconus (KC). Thirty patients with KC and 30 healthy controls were included. Coefficients of repeatability and limits of agreement (LOA) were compared using multiple measurements for inter-observer and inter-device agreement with the Pentacam HR, Orbscan IIz, and Tomey Casia SS-1000. Correlation of repeated measurements was evaluated using a linear mixed effect model (also called random effect model). A formula was derived for the theoretical expected change in precision and compared with measured change. Correlation between measurements from the same eye was small (R = 0.13). The 99.73% LOA (3 SD) of the mean of three measurements, provided better precision than 95% LOA (2 SD) of single cut-off values as expected from statistical theory for uncorrelated measurements for evidence of a significant change in corneal shape in patients with keratoconus. This enabled the determination of cut-off values for the detection of true change in corneal shape. The mean of three repeated measurements will provide better precision when there is minimal correlation. Three (rather than two) standard deviations provides a precise estimate of the LOA within or between observers and can be used as a reliable measure for identifying stage-independent corneal shape changes (progression) in keratoconus.

A 10-year review of underlying diseases for endothelial keratoplasty (DSAEK/DMEK) in a tertiary referral hospital in Japan

Purpose

To report a 10-year review of endothelial keratoplasty (EK) procedures, Descemet's stripping automated endothelial keratoplasty (DSAEK) and Descemet's membrane endothelial keratoplasty (DMEK), and underlying diseases at a tertiary referral hospital in Japan.

Study design

A single-center, retrospective case series.

Methods

We retrospectively reviewed all medical records of bullous keratopathy (BK) surgically treated by EK (DSAEK/DMEK) at Kanazawa University Hospital from January 2007 to December 2016. Changes or modifications to the annual number of EK procedures and underlying diseases were analyzed.

Results

During this period, 320 EK procedures (DSAEK: 288 cases, DMEK: 32 cases) were performed on 250 patients. Total annual EKs gradually increased from 19 to 45 cases between 2007 and 2016. The annual number of DSAEKs was stable, although the proportion of DSAEKs to other procedures decreased significantly as re-DSAEKs and DMEKs increased. BK after argon laser iridotomy (ALI) was the leading cause in 2007, followed by Fuchs' endothelial dystrophy (FED) and failed penetrating keratoplasty. In 2016, BK after trabeculectomy (TLE) was most prevalent, followed by failed DSAEK, failed penetrating keratoplasty, and pseudophakic BK. The decreased ALI and FED, and increased BK after TLE and failed DSAEK were statistically significant.

Conclusion

The distribution of EK procedures (DSAEK/DMEK) and underlying diseases changed over 10 years at a tertiary referral hospital in Japan. The proportion of re-DSAEK and DMEK increased among all EK procedures. Most significantly, among the underlying diseases, decreased ALI and FED and increased TLE and failed DSAEK were observed. Extended multicenter analysis may further elucidate the changes in EK procedures and the causes of BK in Japan.

DMEK versus DSAEK for Fuchs’ endothelial dystrophy: A meta-analysis

Purpose:

To compare the safety and efficacy profiles of Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK) in adult patients with Fuchs’ endothelial dystrophy.

Methods:

Electronic database search on MEDLINE and CENTRAL from inception to August 2017. We included all comparative studies of DMEK versus DSAEK in patients with diagnosed Fuchs’ endothelial dystrophy. Studies assessing rescue procedures were excluded to minimize bias. Primary outcome: mean difference in best-corrected visual acuity (BCVA) at 3, 6, and 12 months postoperatively. Secondary outcomes: rates of graft primary failure, rejection, and rebubbling; other graft-related issues; mean difference in endothelial cell density; subjective visual outcomes; and patient satisfaction.

Results:

A total of 10 retrospective studies of moderate methodological quality were included (n = 947 eyes, 646 DMEK). BCVA was better with DMEK at all evaluated time points (0.16 logMAR at 12 months) comparing to DSAEK (0.30 logMAR; p < 0.001). DMEK had a 60% lower rate of rejection (risk ratio (RR) 0.4, 95% CI (0.24, 0.67), p = 0.0005), but required more rebubblings (RR = 2.48, 95% CI (1.32, 4.64), p = 0.005). DMEK had more primary graft failures and less endothelial cell density loss, but statistical difference was not reached. More patients were satisfied after DMEK (odds ratio = 10.29, 95% CI (3.55, 29.80), p < 0.0001).

Conclusion:

DMEK showed better postoperative results regarding BCVA, patient satisfaction, and graft-related issues. However, the small number of studies with short follow-up times and other methodological issues prompt us to interpret these results carefully.

Outcome of repeat penetrating keratoplasty in eyes with failed penetrating keratoplasty

Objectives:

To report the outcomes of penetrating keratoplasty (PKP) surgeries in eyes with failed PKP.

Methods:

This was a retrospective, non-comparative, descriptive case series. Thirty eyes of 30 patients with failed PKP comprised our study group, they were reviewed from January 2007 to December 2012 at the King Khaled Eye Specialist Hospital, Riyadh, Kingdom of Saudi Arabia. Data were collected on best corrected visual acuity before and after one week, one month, 3 months, 6 months, one year, and 2 years following PKP. Intraoperative and postoperative complications, changes in intraocular pressure (IOP), additional surgical procedure and other ocular comorbidities were also documented. The visual outcomes at 6 months and one year were associated with risk factors.

Results:

Before intervention, 18 (60%) eyes had vision <20/400. Vision was 20/20 to 20/60 in 10 (30%) eyes at 6 months, 17 (57%) eyes at 12 months, and 22 (73%) eyes at 24 months. The variation in IOP at different follow up periods was not significant (p=0.2). The presence of other ocular comorbidity was not significantly associated with functional visual outcome (p=0.4). Additional surgical procedure after repeat PKP enabled a regain of excellent vision in 9 (47%) eyes at one year. The numbers for past corneal surgeries were significantly associated with the visual outcome at 6 months.

Conclusion:

Penetrating keratoplasty to manage failed PKP resulted in reducing visual disabilities.

Changing Indications in Penetrating Keratoplasty: A Systematic Review of 34 Years of Global Reporting

BACKGROUND

Penetrating keratoplasty (PK) ranks among the oldest and most common kinds of human tissue transplantation. Based on the hypothesis that reported indications for PK significantly vary between global regions and over time, the present systematic review aimed to provide a thorough overview of global PK indications as reported in peer-reviewed manuscripts.

METHODS

A literature search of PubMed and MEDLINE was conducted to retrieve articles published from January 1980 to May 2014. Indications for PK within 7 global regions were compared using a modified classification system for PK indications and analyzed via multivariate regression.

RESULTS

A total of 141 publications from 37 countries were included, recording 180 865 PK cases. Postcataract surgery edema was the predominant indication in North America (28.0%) and ranked second in Europe (20.6%), Australia (21.1%), the Middle East (13.6%), Asia (15.5%), and South America (18.6%). Keratoconus was the leading indication in Europe (24.2%), Australia (33.2%), the Middle East (32.8%), Africa (32.4%), and South America (22.8%). It ranked third in North America (14.2%). Keratitis was the primary indication in Asia (32.3%). Fuchs endothelial corneal dystrophy was the fourth most common indication in North America (12.9%) and Europe (10.2%) and fifth in South America (3.8%). Multivariate analysis supported these results and revealed individual regional changes over time.

CONCLUSIONS

Systematic analysis reveals characteristic chronological and regional differences in reported global PK indications. Leading reported indications for PK between 1980 and 2014 were keratoconus (Europe, Australia, the Middle East, Africa, and South America), pseudophakic bullous keratopathy/aphakic bullous keratopathy (North America), and keratitis (Asia).

Trends in Corneal Transplantation in Keratoconus

PURPOSE

To determine recent trends in and sociodemographic/comorbid conditions associated with penetrating keratoplasty (PK) and lamellar keratoplasty (LK) for keratoconus (KCN).

METHODS

Patients with KCN and subsequent PK and LK procedures were identified using International Classification of Diseases, 9th revision (ICD-9) and Current Procedural Terminology (CPT) billing codes. The change in surgical rates was calculated over a decade, and multivariate analysis demonstrated factors associated with undergoing surgery.

RESULTS

A total of 21,588 patients with KCN underwent 1306 PK procedures and 109 LK procedures during the study period. Individuals were significantly less likely to undergo PK from 2009 to 2012 compared with 2001 to 2008 [odds ratio (OR) 0.57, 95% confidence interval (CI) 0.47-0.68, P < 0.001]. Multivariate analysis revealed the factors that increased the likelihood of PK alone and included age 20 to 40 (OR 1.90, 95% CI, 1.19-3.04, P < 0.001), black race (OR 1.36, 95% CI, 1.06-1.74, P = 0.01), and education less than a bachelor's degree or only a high school diploma (OR 1.94-2.84, P < 0.001 for all comparisons). Female sex (OR 0.74, 95% CI, 0.63-0.88, P < 0.001) and household net worth either between 150 and 249k (OR 0.64, 95% CI, 0.48-0.84, P < 0.001) or more than $500,000 (OR 0.71, 95% CI, 0.51-0.99, P = 0.03) were traits associated with decreased odds of PK. No significant associations for LK were observed.

CONCLUSIONS

The rate of PK in KCN is decreasing in the United States. The third or fourth decade of life, male sex, black race, lower education, and greater household net worth are associated with increased odds of PK.

Collagen synthesis disruption and downregulation of core elements of TGF-β, Hippo, and Wnt pathways in keratoconus corneas

To understand better the factors contributing to keratoconus (KTCN), we performed comprehensive transcriptome profiling of human KTCN corneas for the first time using an RNA-Seq approach. Twenty-five KTCN and 25 non-KTCN corneas were enrolled in this study. After RNA extraction, total RNA libraries were prepared and sequenced. The discovery RNA-Seq analysis (in eight KTCN and eight non-KTCN corneas) was conducted first, after which the replication RNA-Seq experiment was performed on a second set of samples (17 KTCN and 17 non-KTCN corneas). Over 82% of the genes and almost 75% of the transcripts detected as differentially expressed in KTCN and non-KTCN corneas were confirmed in the replication study using another set of samples. We used these differentially expressed genes to generate a network of KTCN-deregulated genes. We found an extensive disruption of collagen synthesis and maturation pathways, as well as downregulation of the core elements of the TGF-β, Hippo, and Wnt signaling pathways influencing corneal organization. This first comprehensive transcriptome profiling of human KTCN corneas points further to a complex etiology of KTCN.

Existence of Neural Crest-Derived Progenitor Cells in Normal and Fuchs Endothelial Dystrophy Corneal Endothelium

Human corneal endothelial cells are derived from neural crest and because of postmitotic arrest lack competence to repair cell loss from trauma, aging, and degenerative disorders such as Fuchs endothelial corneal dystrophy (FECD). Herein, we identified a rapidly proliferating subpopulation of cells from the corneal endothelium of adult normal and FECD donors that exhibited features of neural crest-derived progenitor (NCDP) cells by showing absence of senescence with passaging, propensity to form spheres, and increased colony forming efficacy compared with the primary cells. The collective expression of stem cell-related genes SOX2, OCT4, LGR5, TP63 (p63), as well as neural crest marker genes PSIP1 (p75(NTR)), PAX3, SOX9, AP2B1 (AP-2β), and NES, generated a phenotypic footprint of endothelial NCDPs. NCDPs displayed multipotency by differentiating into microtubule-associated protein 2, β-III tubulin, and glial fibrillary acidic protein positive neurons and into p75(NTR)-positive human corneal endothelial cells that exhibited transendothelial resistance of functional endothelium. In conclusion, we found that mitotically incompetent ocular tissue cells contain adult NCDPs that exhibit a profile of transcription factors regulating multipotency and neural crest progenitor characteristics. Identification of normal NCDPs in FECD-affected endothelium holds promise for potential autologous cell therapies.

Corneal stromal demarcation line after accelerated crosslinking using continuous and pulsed light

PURPOSE

To evaluate and compare the depth of corneal stromal demarcation line after accelerated collagen crosslinking (CXL) using continuous and pulsed light ultraviolet-A (UVA) exposure.

SETTING

Department of Ophthalmology, Arcispedale Santa Maria Nuova, Reggio Emilia, Italy.

DESIGN

Retrospective case series.

METHODS

Patients with progressive keratoconus were assigned to 1 of 2 treatment protocols using the same irradiation device for accelerated CXL. Patients assigned to Group A received accelerated CXL using continuous UVA light exposure at 30 mW/cm(2) for 4 minutes. Patients assigned to Group B received accelerated CXL using pulsed UVA light with 8 minutes (1 second on/1 second off) of UVA exposure at 30 mW/cm(2) and energy dose of 7.2 J/cm(2). One month after surgery, corneal stromal demarcation line depth was measured by 2 independent observers using anterior segment optical coherence tomography (AS-OCT).

RESULTS

A total of 60 patients were assessed. Corneal stromal demarcation line was easily identified on AS-OCT scans in all eyes by both observers. The mean depth of stromal demarcation line was 149.32 ± 36.03 μm in Group A and 213 ± 47.38 μm in Group B. The difference in stromal demarcation line depth between groups was statistically significant (P < .001).

CONCLUSIONS

Using accelerated CXL, the corneal stromal demarcation line was significantly deeper using pulsed rather than continuous light exposure.

FINANCIAL DISCLOSURE

No author has financial or proprietary interest in any material or method mentioned.

Trends in Indications and Techniques of Corneal Transplantation in Iran from 2006 to 2013; an 8-year Review

Purpose:

To report changing trends in indications and techniques of corneal transplantation in Iran.

Methods:

We reviewed eye bank records of 47,129 patients who had undergone corneal transplantation between 2006 and 2013 at different eye centers throughout Iran.

Results:

The most common indication for corneal transplantation was keratoconus (KCN, n = 21,350 eyes, 45.3%), followed by bullous keratopathy (BK, n = 8,566 eyes, 18.2%), corneal opacity and scar (COS, n = 7,158 eyes, 15.2%), graft failure (n = 3,252 eyes, 6.9%), corneal dystrophies (n = 2,553 eyes, 5.4%), and infectious keratitis (n = 2,238 eyes, 4.7%). Over the study period, there was a significant increase in the frequency of BK (P = 0.001) and graft failure (P = 0.025), and a significant decrease in the relative frequency of COS (P = 0.012). The prevalence of KCN (P = 0.172), infectious keratitis (P = 0.107), and corneal dystrophies (P = 0.836) remained unchanged. The most common technique of corneal transplantation was penetrating keratoplasty (PKP, n = 33,476 eyes, 71.0%), followed by deep anterior lamellar keratoplasty (DALK, n = 8,363 eyes, 17.7%), Descemet's stripping automated endothelial keratoplasty (DSAEK, n = 3,516 eyes, 7.5%), tectonic (n = 1752, 3.7%), and keratolimbal allograft (KLAL, n = 19 eyes, 0.1%). Regarding the shift in surgical techniques, a significant increase was observed in DSAEK (P < 0.001), whereas PKP was significantly decreased (P = 0.005) over the 8-year period. No significant change was seen in the rates of DALK (P = 0.354), tectonic graft (P > 0.999) and KLAL (P = 0.151).

Conclusion:

KCN was the most common indication and PKP was the most prevalent technique used for corneal transplantation. Significant changes in surgical techniques were observed over the past 8 years; DSAEK demonstrated an increasing trend while PKP showed a decrease.

Evidence against ZNF469 being causative for keratoconus in Polish patients

PURPOSE

Keratoconus (KTCN) is a degenerative disorder characterized by stromal thinning and protrusion of the cornea, resulting in severe impairment of visual function. A recent study proposed that rare heterozygous mutations in ZNF469 determine KTCN aetiology.

METHODS

To investigate the contribution of ZNF469 to KTCN, we Sanger sequenced ZNF469 in 42 unrelated Polish patients with KTCN and 49 Polish individuals with high myopia (HM) and compared the results with whole-exome sequencing (WES) data performed in 268 Polish individuals without ocular abnormalities.

RESULTS

The average number of ZNF469 non-synonymous variants was 16.31 and 16.0 for individuals with KTCN and HM, respectively (p = 0.3724). All identified variants were previously reported. Alternative allele frequency (AAF) was determined based on the WES results. Among missense variants, only one (rs528085780) has AAF ≤ 0.001 and was identified in one patient with sporadic KTCN. However, the resulting Arg1864Lys substitution was not predicted to be deleterious.

CONCLUSION

In summary, we have not found a significant enrichment of sequence variants in ZNF469 in Polish patients with KTCN. High prevalence of ZNF469 variants identified in our KTCN group is typical for a common genetic variation observed in general population. Our findings indicate that variation in ZNF469 is not responsible for KTCN and other genetic variants are involved in the development and progression of this disease in Polish patients.

Changing trends in corneal graft surgery: a ten-year review

AIM

To review indications and corneal tissue use for penetrating and lamellar surgery between 2002 and 2011.

METHODS

The surgical reports of corneal grafts performed during 2002-2011, using tissues supplied by the Eye Bank of Piedmont (Italy), were reviewed retrospectively. Patient demographic data, date of intervention, indication for surgery, and surgical technique used were recorded. Surgical techniques included penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK) and endothelial keratoplasty (EK). The χ (2) test was used to compare the distribution of indications and types of surgical technique used, for corneal grafts done during 2002-2006 versus those done during 2007-2011.

RESULTS

The number of corneal grafts increased by 30.7% from 2002-2006 to 2007-2011 (from 1567 to 2048). Comparing the two periods, both main indications and surgical techniques changed significantly. In 2007-2011, the proportion of interventions for aphakic/pseudophakic bullous keratopathy (from 16.8% to 21.3%), graft failure (from 16.4% to 19.1%) and Fuchs endothelial dystrophy (from 12.8% to 16.7%) all increased significantly (P<0.05), while those for keratoconus decreased significantly (from 35.6% to 27.3%; P<0.001). In 2007-2011, the proportion of PK decreased significantly (from 92.4% to 57.2%; P<0.001) while that of EK and DALK went from 0.4% to 30.2% (P<0.001) and from 7.2% to 12.6% (P<0.001) respectively.

CONCLUSION

During 2002-2011 the number of interventions increased significantly for corneal endothelial diseases and graft failure. The growing demand for interventions for these diseases corresponded to the widespread adoption of EK techniques. The use of DALK also increased, but more moderately than EK procedures.

Indications and techniques employed for keratoplasty in the Eastern province of Saudi Arabia: 6 years of experience

BACKGROUND AND OBJECTIVES

Keratoplasty services in Saudi Arabia have progressed steadily in the past few decades. We sought to identify the leading indications and types of keratoplasty performed in the Eastern Province of Saudi Arabia over a six-year period and to compare these indications with published data.

DESIGN AND SETTING

This was a retrospective descriptive analysis of the records of patients who underwent keratoplasty at four ophthalmology centers in the Eastern Province between 2008 and 2013.

PATIENTS AND METHODS

All keratoplasty procedures were included in the analysis. The primary surgical indication and type of surgery were identified for each case.

RESULTS

Keratoplasties included 570 penetrating keratoplasty, 217 deep lamellar keratoplasty, 80 triple procedures, 24 descemet stripping automated endothelial keratoplasty and 12 Boston keratoprosthesis implantations. The mean age of all patients was 28.8 years (range 14-72 years), and 58.9% of the patient were males. The lead.ing indication for keratoplasty was keratoconus 53.10%, bullous keratopathy 13.80%, corneal scarring 10.7%, regrafts 9.1%, and stromal dystrophies 4.9%.

CONCLUSIONS

In this study, the leading indications for keratoplasty were keratoconus, bullous keratopathy, corneal scarring, regrafts and stromal dystrophies. A significant increasing trend for descemet's stripping automated endothelial keratoplasty surgeries was observed in spite of the number of cases.

Immunosuppressants for the prophylaxis of corneal graft rejection after penetrating keratoplasty

BACKGROUND

Penetrating keratoplasty is a corneal transplantation procedure in which a full-thickness cornea from the host is replaced by a graft from a donor. The use of various immunosuppressants to prevent graft rejection, the most common cause of graft failure in the late postoperative period, is increasing.

OBJECTIVES

To assess the effectiveness of immunosuppressants in the prophylaxis of corneal allograft rejection after high- and normal-risk keratoplasty.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2015, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2015), EMBASE (January 1980 to May 2015), China National Knowledge Infrastructure (CNKI) (January 1913 to February 2015), VIP database (January 1989 to February 2015), Wanfang Data (www.wanfangdata.com) (January 1990 to February 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the English language databases on 18 May 2015 and the Chinese language databases on 20 February 2015.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) assessing the use of immunosuppressants in the prevention of graft rejection, irrespective of publication language.

DATA COLLECTION AND ANALYSIS

We used standard procedures expected by Cochrane. The primary outcome was clear graft survival at 12 months after penetrating keratoplasty. Secondary outcomes included graft rejection, best-corrected visual acuity, and quality of life. We defined 'high-risk keratoplasty' as repeat keratoplasty and other indications of reduced graft survival.

MAIN RESULTS

We included six studies conducted in Germany (three studies), Iran, India, and China. Three studies were conducted in people undergoing high-risk keratoplasty and investigated three different comparisons: systemic mycophenolate mofetil (MMF) versus no MMF; systemic MMF versus systemic cyclosporine A (CsA); and topical CsA versus placebo. One study compared topical tacrolimus to topical steroid in people with normal-risk keratoplasty, and two studies compared topical CsA to placebo in people experiencing graft rejection after normal-risk keratoplasty. Overall, we considered the trials to be at unclear or high risk of bias.MMF may not improve clear graft survival (risk ratio (RR) 1.06, 95% confidence interval (CI) 0.84 to 1.33, 1 RCT, 87 participants, low-quality evidence) but may reduce the risk of graft rejection (RR 0.49, 95% CI 0.22 to 1.08, 1 RCT, 87 participants, low-quality evidence) compared to no MMF. Visual acuity was not reported.In 1 study of 52 people comparing systemic MMF and systemic CsA, there were no graft failures in the first year of follow-up. Data from the longest follow-up (three years) suggest that there may be little difference in the effect of these two treatments on clear graft survival (RR 1.10, 95% CI 0.90 to 1.35, low-quality evidence). There was low-quality evidence of an increased risk of graft rejection with systemic MMF compared to systemic CsA, but with wide CIs compatible with increased risk with systemic CsA (RR 1.48, 95% CI 0.56 to 3.93, low-quality evidence). Visual acuity was not reported.One study of 84 people comparing topical CsA to placebo did not report clear graft survival at 1 year, which suggests that all grafts survived to 1 year. This study suggests that the use of topical CsA probably leads to little or no difference in graft rejection (RR 1.00, 95% CI 0.39 to 2.58, moderate-quality evidence). At one year, the mean difference (MD) between the two groups in visual acuity was 0.07 (95% CI -0.01 to 0.15, moderate-quality evidence).Topical CsA probably does not have an effect on clear graft survival in people experiencing graft rejection after normal-risk keratoplasty compared to placebo (RR 1.03, 95% CI 0.96 to 1.10, 2 RCTs, 283 participants, moderate-quality evidence). There were inconsistent findings on graft rejection, with one study reporting a reduced incidence of graft rejection in the CsA group (RR 0.35, 95% CI 0.14 to 0.87, 230 participants) but the other study reporting a higher average number of episodes of graft rejection in people treated with CsA (MD 1.30, 95% CI 0.39 to 2.21, 43 participants). Overall, we judged this to be low-quality evidence due to risk of bias and inconsistency. There was no evidence for a difference in visual acuity between the 2 groups at final follow-up (approximately 18 months, range 2 to 33 months) (MD 0.04, 95% CI -0.10 to 0.18, 1 RCT, 43 participants, low-quality evidence).In 1 study comparing topical tacrolimus to topical steroid, the graft survived in all of the 12 treated participants and 20 control participants at 6 months. Graft rejection was rare (0 out of 12 versus 2 out of 20) (RR 0.32, 95% CI 0.02 to 6.21, low-quality evidence). Visual acuity was not reported.None of the studies reported on quality of life. We identified an unpublished trial of basiliximab (Simulect) (NCT00409656), probably completed in 2005.

AUTHORS' CONCLUSIONS

Current evidence on the effect of immunosuppressants in the prevention of graft failure and rejection after high- and normal-risk keratoplasty is largely low quality because the number of trials was limited, and, in general, the trials were small and at risk of bias. Future trials should be large enough to detect important clinical effects, conducted with a view to minimising the risk of bias, and they should measure outcomes important to patients.

Molecular Screening of Keratoconus Susceptibility Sequence Variants in VSX1, TGFBI, DOCK9, STK24, and IPO5 Genes in Polish Patients and Novel TGFBI Variant Identification

PURPOSE

Keratoconus (KTCN) is a degenerative disorder of the eye that results in the conical shape and thinning of the cornea and is a leading cause for corneal transplantations. A number of studies suggest that genetic factors play a role in KTCN etiology. Some candidate gene variants have recently been shown to be associated with KTCN. The purpose of our study was to verify the role of VSX1, TGFBI, DOCK9, IPO5, and STK24 sequence variants in Polish KTCN patients.

METHODS

Forty-two Polish patients with sporadic KTCN and 50 control individuals were enrolled into this study. Both affected and unaffected individuals underwent detailed ophthalmic examination. The mutations screening in the candidate genes was performed by the direct sequencing method.

RESULTS

Analysis of VSX1, TGFBI, DOCK9, IPO5, and STK24 genes identified numerous sequence variants. Variants c.-264_-255delGGGGTGGGGT, c.627 + 23G > A, c.809-6_809-5insT, and c.*200G > T in the VSX1 gene, and heterozygous c.1598G > A mutation (Arg533Gln) in exon 12 of TGFBI were detected for the first time in KTCN patients. Two known sequence variants of TGFBI c.1620T > C (Phe540Phe) and c.1678 + 23G > A were observed in KTCN patients and control individuals. The newly reported c.717 + 43A > G substitution in intron 7 of DOCK9 was identified in both KTCN patients and healthy individuals.

CONCLUSIONS

Our investigation showed that KTCN-related sequence variants of analyzed genes were found in a very small proportion of the studied patients indicating that genes other than VSX1, TGFBI, DOCK9, IPO5, and STK24 are involved in the development and progression of KTCN in Polish patients. Our results support the hypothesis about the genetic heterogeneity of KTCN.

Serial biomechanical comparison of edematous, normal, and collagen crosslinked human donor corneas using optical coherence elastography

PURPOSE

To noninvasively evaluate the effects of corneal hydration and collagen crosslinking (CXL) on the mechanical behavior of the cornea.

SETTING

Cleveland Clinic Cole Eye Institute, Cleveland, Ohio, USA.

DESIGN

Experimental study.

METHODS

An optical coherence elastography (OCE) technique was used to measure the displacement behavior of 5 pairs of debrided human donor globes in 3 serial states as follows: edematous, normal thickness, and after riboflavin-ultraviolet-A-mediated CXL. During micromotor-controlled axial displacements with a curved goniolens at physiologic intraocular pressure (IOP), serial optical coherence tomography scans were obtained to allow high-resolution intrastromal speckle tracking and displacement measurements over the central 4.0 mm of the cornea.

RESULTS

With no imposed increase in IOP, the mean lateral to imposed axial displacement ratios were 0.035 μm/μm ± 0.037 (SD) in edematous corneas, 0.021 ± 0.02 μm/μm in normal thickness corneas, and 0.014 ± 0.009 μm/μm in post-CXL corneas. The differences were statistically significant (P<.05, analysis of variance) and indicated a 40% increase in lateral stromal resistance with deturgescence and a further 33% mean increase in relative stiffness with CXL.

CONCLUSIONS

Serial perturbations of the corneal hydration state and CXL had significant effects on corneal biomechanical behavior. With an axially applied stress from a nonapplanating contact lens, displacements along the direction of the collagen lamellae were 2 orders of magnitude lower than axial deformations. These experiments show the ability of OCE to quantify clinically relevant mechanical property differences under physiologic conditions.

FINANCIAL DISCLOSURES

Proprietary or commercial disclosures are listed after the references.

Fuchs endothelial cornea dystrophy: a review of the genetics behind disease development

Fuchs dystrophy represents the most common form of endothelial dystrophy and is a significant cause of visual impairment. The cause of Fuchs dystrophy is a complicated combination of both genetic and environmental factors. Understanding the underlying causes of the disease can potentially lead to new medical treatments preventing loss of vision.

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?

Indications of penetrating keratoplasty in southern India

AIM

To study the indications of penetrating keratoplasty in Southern India.

SETTINGS AND DESIGN

Retrospective study.

MATERIAL AND METHODS

Retrospective evaluation of eye bank records from December, 2002 to December, 2012 with respect to indications for penetrating keratoplasty.

RESULTS

During the period considered for study, 102 penetrating keratoplasties were performed. The leading indications for penetrating keratoplasty were corneal scarring (60.7%), followed by regrafting (12.7%), spheroidal degeneration (9.8%), aphakic bullous keratopathy (5.88%), pseudophakic bullous keratopathy (2.94%), acute infectious keratitis (2.94%), corneal dystrophy and keratoconus (4.9%). Healed infectious keratitis (72.88%) was the most common subcategory among the eyes with corneal scarring followed by traumatic corneal scars (16.12%).

CONCLUSION

Corneal scarring from healed infectious keratitis are the most common indication for keratoplasty in Southern India.

Lithium treatment increases endothelial cell survival and autophagy in a mouse model of Fuchs endothelial corneal dystrophy

BACKGROUND

Lithium previously has been shown to reduce both endoplasmic reticulum (ER) and oxidative stress in other in vitro and in vivo model systems. We investigated lithium's effects on cultured corneal endothelial cells (CECs) exposed to these types of stress and in a mouse model of Fuchs endothelial corneal dystrophy (FECD).

METHODS

Viability of cultured bovine CECs was determined by CellTiter-Glo. 2-month-old Col8a2(Q455K/Q455K) mutant (Q455K) and C57/Bl6 wild type animals were divided into two groups of 15 mice. Group I received 0.2% lithium carbonate-containing chow and Group II received control chow for 7 months. Confocal microscopy, transmission electron microscopy, real-time PCR (RT-PCR) and western blot were performed.

RESULTS

Pretreatment with lithium increased viability of cultured CECs after H2O2 and thapsigargin exposure compared with untreated controls (p<0.05). In vivo analysis of mouse corneal endothelium showed the following: endothelial cell density of lithium treated Q455K was higher than for untreated Q455K (p<0.01). transmission electron microscopy of lithium treated Q455K showed normal endothelium with enlarged autophagosomes, but untreated Q455K showed dilated ER and guttae. Compared with untreated Q455K endothelium, lithium treated Q455K showed significant upregulation of P62, Tmem74, Tm9sf1 and Tmem166 by RT-PCR and of Atg5-12 conjugate by western blotting indicating that lithium treatment increased autophagy. Although RT-PCR unexpectedly showed increased levels of lithium response genes, caspase 12, Gsk3β, Arrβ2 and Impa1, western blotting showed the expected downregulation of Arrβ2 and Impa1 proteins in response to lithium treatment.

CONCLUSIONS

Lithium increases cultured CEC survival against ER and oxidative stress. Increased autophagy in lithium treated endothelium in a mouse model of FECD suggests autophagy may contribute to increased endothelial cell survival.

Investigation of VSX1 sequence variants in South Indian patients with sporadic cases of keratoconus

Background

The involvement of VSX1 gene for the genetic basis of keratoconus is unclear and controversial. The genetic screening of VSX1 from different ethnic populations can enlighten this subject. The aim of the present study is to investigate the role of VSX1 gene in patients with sporadic cases of keratoconus from South India.

Methods

The VSX1 gene coding regions, including exon-intron boundaries were screened by direct sequencing analysis in 117 sporadic cases of keratoconus. The identified variations were also analyzed in 108 ethnic matched healthy blood donors.

Results

In the VSX1 gene screening, no pathogenic mutation was identified, whereas we could find the presence of four reported single nucleotide polymorphisms; c.546A>G (rs12480307), c.627+23G>A (rs6138482), c.627+84T>A (rs56157240) and c.504-24C>T (IVS3-24C). These variations were observed in similar frequency between cases and controls.

Conclusions

The lack of VSX1 pathogenic variations in a large number of unrelated sporadic keratoconus patients tend to omit its role, and corroborate the involvement of other genetic, environmental or behavioural factors in the development of this complex disorder.

Functional corneal endothelium derived from corneal stroma stem cells of neural crest origin by retinoic acid and Wnt/β-catenin signaling

Corneal endothelial dysfunction remains a major indication for corneal transplantation. Both corneal endothelial cells and stromal cells originate from the neural crest, but have distinct phenotypes and function in the adult cornea. We previously reported that stem cells isolated from the adult corneal stroma [cornea-derived precursors (COPs)] show characteristics of multipotent neural crest-derived stem cells. In this study, we report the induction of functional tissue-engineered corneal endothelium (TECE) from mouse and human COPs. TECE was engineered from Wnt1-Cre/Floxed EGFP mouse COPs in a medium containing retinoic acid and glycogen synthase kinase (GSK) 3β inhibitor (activator of Wnt/β-catenin signaling). The expression levels of major markers characterizing corneal endothelial function (Atp1a1, Slc4a4, Car2, Col4a2, Col8a2, and Cdh2) were significantly upregulated. Both retinoic acid and GSK 3β inhibitor upregulated the expression of Pitx2, a homeobox gene involved in the development of the anterior segment of the eye. GSK 3β inhibitor increased Atp1a1 expression and Na,K-ATPase pump activity of TECE, which was significantly higher than COPs or control 3T3 cells, and 2.6-fold higher than cultured mouse corneal endothelial cells. Mouse TECE transplanted into rabbit corneas maintained transparency and corneal thickness, whereas control corneas without TECE showed marked edema and increased corneal thickness. Furthermore, we successfully induced TECE from human COPs, and human TECE transplanted into rabbit corneas also maintained corneal transparency and thickness. This protocol enables efficient production of corneal endothelium from corneal stromal stem cells by direct induction, which may lead to a novel stem cell therapy for corneal endothelial dysfunction.

Changing indications and surgical techniques for corneal transplantation between 2004 and 2009 at a tertiary referral center

Purpose:

The aim of this study is to report the indications, techniques, and clinical outcomes of corneal transplantation and investigate any changing trends in surgical techniques over a 6 year period.

Materials and Methods:

Records of patients who had undergone any kind of corneal transplantation at Labbafinejad Medical Center, Tehran, Iran, from January 2004 to December 2009 were reviewed to determine the indications and types of corneal transplantation. Postoperative best-corrected visual acuity, refractive error, graft clarity, and complications were reported.

Results:

During this period, 1859 eyes of 1624 patients with a mean age of 41.3 ± 21.3 years underwent corneal transplantation. The most common indication was keratoconus (38.4%) followed by aphakic/pseudophakic bullous keratopathy (11.7%), previous failed grafts (10.6%), infectious corneal ulcers (10.1%), non-herpetic corneal scars (7.6%), trachoma keratopathy (4.7%), stromal corneal dystrophies (4.6%), post-herpetic corneal scar (3.7%), Fuchs’ endothelial dystrophy (0.8%), and congenital hereditary endothelial dystrophy (0.4%). Techniques of corneal transplantation included penetrating keratoplasty (PKP; 70.9%), deep anterior lamellar keratoplasty (DALK; 20.1%), conventional lamellar keratoplasty (LKP; 4.4%), and Descemet's stripping automated endothelial keratoplasty (DSAEK; 2.3%). Over the study period, there was a significant increase in the relative frequency of infectious corneal ulcers, failed grafts, and trachoma keratopathy. Additionally, a significant reduction was observed in PKP and LKP procedures, and volume of DALK and DSAEK increased significantly. At final follow-up, 69.0% of grafts were clear in the PKP group. This figure was 82.6%, 82.7%, and 97.6% in the DALK, LKP, and DSAEK groups, respectively.

Conclusion:

Keratoconus was the most common indication and PKP was the most prevalent technique used for corneal transplantation. However, significant changes in the indications and surgical techniques were observed from 2004 to 2009.