Outcome of penetrating keratoplasty in patients with bilateral corneal blindness

Demographic and Socioeconomic Determinants of Penetrating Keratoplasty Outcomes

PURPOSE

The aim of this study was to determine possible associations between demographic and socioeconomic factors and graft survival after penetrating keratoplasty (PK).

METHODS

This study was a retrospective chart review of patients undergoing PK at a tertiary-care corneal practice at Wills Eye Hospital between May 1, 2007, and September 1, 2018. The first PK of the first eye was included. The primary outcome measure was graft failure, defined as irreversible and visually significant graft edema, haze, or scarring. Demographic and socioeconomic factors included yearly average adjusted gross income (AGI) based on residential zip code, age, sex, and race. Two income groups were created: 1) individuals from neighborhoods with the lowest 10% of AGI (N = 82, AGI=$32,100 ± 4000) and 2) the remaining 90% of individuals (N = 740, AGI=$86,900 ± 52,200). Logistic regression analysis was performed to identify factors predictive of graft prognosis.

RESULTS

The 822 patients (822 eyes) included had a mean age of 57.1 ± 22.1 years at the time of PK. Over an average of 4.2 ± 3.1 years of follow-up, graft failure occurred in 35.3%. Age, sex, and follow-up duration were comparable between income groups (all P > 0.05). Black race was disproportionately represented in the lower-income group (50.0% vs. 11.5%, P < 0.001). Multivariable analysis identified predictors of graft failure including residing in a lower-income neighborhood [hazard ratio (HR) = 2.27, 95% confidence interval (CI) = 1.24-4.19, P = 0.008], younger age (HR = 0.99, 95% CI = 0.98-1.00, P = 0.046), and Black race (HR = 1.63, 95% CI = 1.03-2.56, P = 0.035).

CONCLUSIONS

Individuals with a lower income, younger age, and Black race may be more vulnerable to graft failure after PK. Further studies are warranted to identify reasons for these associations.

Corneal Regeneration Using Gene Therapy Approaches

One of the most remarkable advancements in medical treatments of corneal diseases in recent decades has been corneal transplantation. However, corneal transplants, including lamellar strategies, have their own set of challenges, such as graft rejection, delayed graft failure, shortage of donor corneas, repeated treatments, and post-surgical complications. Corneal defects and diseases are one of the leading causes of blindness globally; therefore, there is a need for gene-based interventions that may mitigate some of these challenges and help reduce the burden of blindness. Corneas being immune-advantaged, uniquely avascular, and transparent is ideal for gene therapy approaches. Well-established corneal surgical techniques as well as their ease of accessibility for examination and manipulation makes corneas suitable for in vivo and ex vivo gene therapy. In this review, we focus on the most recent advances in the area of corneal regeneration using gene therapy and on the strategies involved in the development of such therapies. We also discuss the challenges and potential of gene therapy for the treatment of corneal diseases. Additionally, we discuss the translational aspects of gene therapy, including different types of vectors, particularly focusing on recombinant AAV that may help advance targeted therapeutics for corneal defects and diseases.

Multiple deprivation, vision loss, and ophthalmic disease in adults: global perspectives

The association between socioeconomic position and morbidity and mortality has long been recognized. We evaluate the evidence for an association between multiple aspects of deprivation and ocular health in a global context. This is a systematic review of studies that evaluated deprivation in the adult population in the context of the major acquired causes of visual loss such as cataract, diabetic eye disease, glaucoma, age-related macular degeneration, and ocular trauma. The search strategy identified relevant studies reported between 1946 and August 2016, with randomized control trials, case-control, cohort, and cross-sectional study designs being selected for inclusion. The studies identified in this review from across the world demonstrate the extent to which the common themes such as low educational attainment and low income may be associated with increased incidence of various sight-threatening conditions and may adversely affect access to specialist assessment and delivery of treatment. Health inequality may always persist, but an increased recognition of the importance of the various impacts of deprivation may empower policy makers to target limited resources to the most vulnerable groups in order to deliver the greatest benefit.

Corneal Transplantation in Disease Affecting Only One Eye: Does It Make a Difference to Habitual Binocular Viewing?

BACKGROUND

Clarity of the transplanted tissue and restoration of visual acuity are the two primary metrics for evaluating the success of corneal transplantation. Participation of the transplanted eye in habitual binocular viewing is seldom evaluated post-operatively. In unilateral corneal disease, the transplanted eye may remain functionally inactive during binocular viewing due to its suboptimal visual acuity and poor image quality, vis-à-vis the healthy fellow eye.

METHODS AND FINDINGS

This study prospectively quantified the contribution of the transplanted eye towards habitual binocular viewing in 25 cases with unilateral transplants [40 yrs (IQR: 32-42 yrs) and 25 age-matched controls [30 yrs (25-37 yrs)]. Binocular functions including visual field extent, high-contrast logMAR acuity, suppression threshold and stereoacuity were assessed using standard psychophysical paradigms. Optical quality of all eyes was determined from wavefront aberrometry measurements. Binocular visual field expanded by a median 21% (IQR: 18-29%) compared to the monocular field of cases and controls (p = 0.63). Binocular logMAR acuity [0.0 (0.0-0.0)] almost always followed the fellow eye's acuity [0.00 (0.00 --0.02)] (r = 0.82), independent of the transplanted eye's acuity [0.34 (0.2-0.5)] (r = 0.04). Suppression threshold and stereoacuity were poorer in cases [30.1% (13.5-44.3%); 620.8 arc sec (370.3-988.2 arc sec)] than in controls [79% (63.5-100%); 16.3 arc sec (10.6-25.5 arc sec)] (p<0.001). Higher-order wavefront aberrations of the transplanted eye [0.34 μ (0.21-0.51 μ)] were higher than the fellow eye [0.07 μ (0.05-0.11 μ)] (p<0.001) and their reduction with RGP contact lenses [0.09 μ (0.08-0.12 μ)] significantly improved the suppression threshold [65% (50-72%)] and stereoacuity [56.6 arc sec (47.7-181.6 arc sec)] (p<0.001).

CONCLUSIONS

In unilateral corneal disease, the transplanted eye does participate in gross binocular viewing but offers limited support to fine levels of binocularity. Improvement in the transplanted eye's optics enhances its participation in binocular viewing. Current metrics of this treatment success can expand to include measures of binocularity to assess the functional benefit of the transplantation process in unilateral corneal disease.

Penetrating keratoplasty for unilateral corneal disease: outcomes from a tertiary care hospital in Australia

PURPOSE

To assess the visual outcome after unilateral penetrating keratoplasty (PKP) in a heterogenous group of patients with unilateral corneal disease.

METHODS

A retrospective analysis of hospital records of patients who had undergone PKP at the Royal Victorian Eye and Ear Hospital, Melbourne, Australia, over a 10-year period, was performed. All cases with a history of corneal transplantation surgery in one eye and a best-corrected visual acuity (BCVA) more than or equal to 0.5 in the fellow eye with no corneal pathologic condition were included. Outcome measures included BCVA at 2 years, and overall graft survival.

RESULTS

Of the 498 grafts performed during the study period, 30 eyes (6%) met the inclusion criteria. The most common indications for PKP in the study group were bullous keratopathy (40%) and keratoconus (34%). The mean postoperative BCVA at 2 years (0.31 +/- 0.25; range, 0.033-1) was less than the mean BCVA of the fellow eye (0.77 +/- 0.20; range, 0.5-1) (P<0.00). Although there was a significant difference between the preoperative and postoperative BCVA (P<0.00), only 22% of patients could attain BCVA of more than or equal to 0.5. The major complications encountered were graft rejection (40%) and secondary graft failure (20%).

CONCLUSIONS

Unilateral PKP is most commonly performed to treat bullous keratopathy and keratoconus in Australia and may be associated with suboptimal visual outcome as compared to the normal fellow eye.