Clinical outcomes of gamma-irradiated sterile cornea in aqueous drainage device surgery: a multicenter retrospective study

Acute Sterile Keratolysis After Deep Anterior Lamellar Keratoplasty in a Patient With Keratoconus: A Case Report

PURPOSE

The purpose of this study was to report the outcomes of using gamma-irradiated sterile cornea (GISC) as a deep lamellar keratoplasty (DALK) graft in a patient with keratoconus.

METHODS

This is a case report.

RESULTS

A 33-year-old male patient diagnosed with keratoconus underwent DALK using a GISC and developed a persistent epithelial defect which eventually led to sterile keratolysis necessitating further surgical interventions. Management and slitlamp photography, anterior segment optical coherence tomography (AS-OCT), and histopathological examination of the explanted graft are described in detail.

CONCLUSIONS

This is the first reported case of sterile keratolysis after the use of GISC lenticule in DALK in a healthy patient with keratoconus. The underlying pathophysiology is not clearly understood, and some theories have been proposed in this report. Surgeons need to be aware of this rare complication and are encouraged to have a low threshold for graft replacement to ensure good clinical and visual outcomes. Developing a prospective complication registry to document complications after the use of GISC lenticules in ophthalmic surgery is recommended.

Review of Gamma-Irradiated Sterile Cornea: Properties, Indications, and New Directions

ABSTRACT

Gamma-irradiated sterile cornea (GISC) is a relatively new graft tissue that follows the 30-year success of irradiation to other tissues (bone and sclera) to lessen antigenic load and infection transmission. It can serve as a graft to cover glaucoma drainage devices, as graft tissue for frank or impending corneal perforations in tectonic keratoplasty, as graft tissue in lamellar keratoplasty, and as carrier tissue for keratoprosthesis. With the limited availability of fresh corneal tissue in less developed countries, GISC may fill a need for corneal tissue worldwide. It can be used in situations where corneal endothelium is not needed and with a greatly reduced risk of rejection and infection because of the effect of irradiation on corneal tissue.

Management of endophthalmitis related to glaucoma drainage devices: review of the literature and our experience

Glaucoma drainage device (GDD)-related endophthalmitis is a devastating complication of device implantation. There are no guidelines in the literature to assist clinicians in deciding if the GDD should be explanted or if patients require pars plana vitrectomy (PPV). This study compares the outcomes of GDD explantation with device retention and also independently compares the outcomes of PPV versus intravitreal antibiotics alone in patients with GDD-related endophthalmitis. A literature search for studies discussing GDD-related endophthalmitis from 2005 to 2019 was performed; 30 articles were included. The visual acuity/anatomical outcomes were compared between GDD explantation and retention, and between patients that received a PPV and those that did not. These outcomes were combined with a medical records review of 13 patients with GDD-related endophthalmitis from an academic institution. A total of 88 eyes were included. 70.5% underwent GDD explantation, while 37.8% received a PPV. GDD explantation was associated with a lower rate of evisceration/enucleation when compared to GDD retention (4.8% versus 19.2%, OR 0.22, 95% CI 0.05-1.01, p = 0.05), but visual acuity outcomes were similar. No eyes that received an immediate vitrectomy became phthisic or required evisceration/enucleation, compared an evisceration/enucleation rate of 15.2% in eyes treated solely with intravitreal antibiotics (OR 1.18, 95% CI 1.04-1.33, p = 0.04). Explantation of the GDD and immediate vitrectomy are both associated with better anatomical outcomes in GDD-related endophthalmitis. Further research is needed to provide more definitive guidelines in the ideal management of these patients.

Assessing patient cosmetic satisfaction after glaucoma drainage device surgery for different patch grafts

BACKGROUND

The use of a tissue patch graft is common practice with a glaucoma drainage device (GDD). Patch grafts can be visible in the palpebral fissure and may be cosmetically displeasing for some patients. The aim of this study was to report the cosmetic satisfaction of pericardial, scleral, and corneal patch grafts related to superior GDD surgery.

METHODS

Baseline clinical data were collected for consecutive patients with glaucoma operated between 2014 and 2019 at two tertiary eye care institutions (for superiorly-placed) Ahmad glaucoma valve implant using sclera, cornea and pericardium patch graft. A patient questionnaire that contained 4 concise questions, with a Likert-scale grading relating to cosmetic satisfaction was administered by a telephone-based interview. Responses and scores for each question were compared across patients who received the three different types of graft. A binominal logistic regression analysis was used to assess the effects of age, gender, type of graft, number of previous ocular surgeries, and final visual acuity to explain differences.

RESULTS

We included 92 patients who met our inclusion criteria (24 patients received a corneal patch graft, 30 who received sclera and 38 who received pericardium). The mean (±SD) age was 50 (±17.5) years, and the average follow up was 20.7 (± 18.6) months. Regardless of the type of patch graft, most (67-84%) of patients were satisfied with the appearance of their eyes. Patients who received cornea or sclera were more likely to report that their eye looked 'abnormal' by others. Younger age was significantly associated with the response to this question.

CONCLUSION

Patients are generally satisfied with the appearance of their eye following GDD surgery with each of the patch grafts for superiorly-placed GDDs. Younger patients with cornea or sclera were more likely to report that their eyes looked abnormal.

Factors predicting long-term changes in refraction after lamellar keratoscleroplasty in children with limbal dermoids

OBJECTIVES

The objective of this study is to determine the factors that predict long-term changes in refraction after lamellar keratoscleroplasty in paediatric patients with limbal dermoids.

METHODS

A retrospective study of 66 children with limbal dermoids who had lamellar keratoscleroplasty correction with more than 1-year follow-up. Univariate and multivariate regression analyses were performed to investigate factors associated with the long term in refractive parameters, including spherical equivalent, astigmatism, and mean keratometry. The change value was defined as the postoperative refractive value minus the preoperative refractive value. The lower the value of changes, the more satisfied the effects on the correction of the preoperative refraction.

RESULTS

A total of 66 patients (mean surgical age: 3.5 ± 2.1 years) were assessed with at least 1-year follow-up. Amblyopia treatment duration was the only independent factor predicting the long-term changes in spherical equivalent between baseline and last follow-up visit (β = -0.030, P < 0.001). Lesion encroachment on the central and paracentral cornea (β = 0.502, P = 0.024), suture-related complications (β = 1.571, P < 0.001) and graft rejection (β = 0.983, P = 0.035) were significantly correlated with long-term changes in astigmatism. The long-term changes in refraction were not correlated with surgical age, lesion size, lesion depth, steroid-induced high intraocular pressure and changes in mean keratometry.

CONCLUSION

Suture-related complications and graft rejection should be carefully observed and appropriately treated in order to avoid the possible postoperative increase in astigmatism, especially for patients with lesion encroachment on the central and paracentral cornea. The long-duration amblyopia treatment after surgery appears to have a better correction effect on spherical equivalent in the long term, compared with astigmatism.

A review of long-term corneal preservation techniques: Relevance and renewed interests in the COVID-19 era

The growth of eye banking in India was showing positive trends until the nation was hit by unprecedented times as a result of the COVID-19 pandemic. The impact of this has led to a downward spiraling in eye banking activities globally. Several measures had to be implemented to tide over the crisis and strategies planned for future to prepare for the needs of corneal transplantation. While eye banks in India have been practicing short- term and intermediate storage preservation media, there is a definite need to evolve other methods of very long-term preservation. This review discusses various methods of long term corneal preservation, their relevance and applications in the present times. We reviewed relevant medical literature in English from PUBMED with the key words “Corneal preservation”, “Cryopreservation”, “Glycerol preservation”, Gamma Irradiation”, “Eye Banking” ,”COVID-19”.

Long-term clinical outcomes of keratoplasty using gamma-irradiated corneal lenticules

Objective

To report long-term clinical outcomes of gamma-irradiated corneal lenticules in partial and full-thickness keratoplasty.

Methods and Analysis

This multicentre, retrospective case series includes 23 patients who underwent surgery at three centres (India, Guatemala, and USA) between May 2009 and March 2018. The main outcome measures were epithelialization and retention for therapeutic keratoplasty and best spectacle-corrected visual acuity (BSCVA) for optical keratoplasty.

Results

Patients were categorised according to primary aetiology requiring corneal transplantation: non-inflammatory conditions, infectious keratitis and sterile keratolysis. Nine patients with non-inflammatory conditions underwent anterior lamellar keratoplasty (n=7) and Boston type 1 keratoprosthesis (n=2). All nine grafts remained intact and epithelialized during follow-up (median 24 months). In the seven patients who underwent anterior keratoplasty, the graft stayed optically clear during follow-up (median 12 months), with BSCVA between 20/20 and 20/40 in all but one patient who developed cataract. Nine patients with severe infectious keratitis had emergency patch grafting. Six of those grafts epithelialized and remained intact over a median of 30 months, providing tectonic support until optical keratoplasty with fresh tissue could be performed. Three grafts had recurrent infectious keratitis 1–3 months postoperatively, two of which underwent tectonic keratoplasty with fresh tissue which also eventually became infected during follow-up. In five additional patients with sterile keratolysis who underwent lamellar patch graft, two grafts remained intact during follow-up (median 36 months). Two patients had recurrent corneal melt within 1 month, and both had subsequent corneal surgery with fresh tissue which also failed. There were no donor-related complications.

Conclusion

Gamma-irradiated sterile corneal stromal lenticules can be considered as a viable alternative to fresh tissue in various clinical settings.

Electron Beam Irradiated Corneal Versus Gamma-Irradiated Scleral Patch Graft Erosion Rates in Glaucoma Drainage Device Surgery

INTRODUCTION

Patch graft erosion and implant exposure is a known complication of glaucoma drainage device (GDD) surgery. Recently, electron beam (e-beam) irradiated corneal tissue ha s become available; however, limited data exist on the rates of erosion for e-beam irradiated corneal grafts compared to traditional scleral grafts after GDD surgery.

METHODS

This retrospective study examines the records of 253 eyes from 225 adult subjects who underwent GDD surgery with either e-beam irradiated corneal or scleral grafts at the Casey Eye Institute by five surgeons between April 22, 2014 and October 11, 2017. Surgical procedures and the occurrence of graft erosion were determined using billing codes and verified by manual review of electronic health records.

RESULTS

The average age at the time of surgery was 61.3 ± 17.5 years (n = 200) and 60.8 ± 16.8 years (n = 53) for the e-beam irradiated cornea and sclera groups, respectively. The average follow-up time post-surgery was 416 ± 345 days and 495 ± 343 days for the e-beam irradiated cornea and sclera groups, respectively. There were no statistically significant differences in sex, age, follow-up time, and glaucoma diagnosis between the groups; however, the e-beam irradiated cornea group was statistically more likely to have an Ahmed implant as compared to the sclera group. No erosion events were noted in either group.

CONCLUSION

e-Beam irradiated corneal grafts were used 3.8 times more frequently relative to scleral grafts, yet there were no cases of graft erosion in either group during the follow-up period.

Long-Term Functional Outcomes of Glaucoma Tube Shunt Revision Surgery

PURPOSE

To characterize long-term outcomes of tube shunt revision surgeries and identify factors associated with their failure.

DESIGN

Retrospective chart review.

PARTICIPANTS

One eye from each of 179 patients who underwent tube shunt revision surgery at the Wilmer Eye Institute between 2004 and 2015 with a minimum follow-up of 6 weeks.

METHODS

Eligible eyes were identified from billing records and data related to their care were extracted from electronic medical records. Eyes were analyzed in aggregate and by indication for revision, including hypotony, high intraocular pressure (IOP), tube reposition, and tube exposure.

MAIN OUTCOME MEASURES

Surgical failure, defined as a need for further tube shunt revision or other glaucoma surgery, unsatisfactory IOP at last follow-up, or both. Secondary outcomes included postoperative infection and functional visual impairment.

RESULTS

With a median follow-up of 4.2 years, 126 failures occurred among 179 eyes. By Kaplan-Meier analysis, the cumulative rates of surgical failure at 1, 2, and 5 years after revision were 49%, 59%, and 74%, respectively. Most revision failures (105/126) were the result of the need for additional surgery, whereas 11 eyes showed IOP above target levels and 10 eyes showed dysfunctionally low IOP at the last follow-up. Factors associated with failure in a stepwise regression model were revision for hypotony (hazard ratio [HR], 6.79; P = 0.002), different surgeons performing the original and revision surgeries (HR, 2.80; P = 0.002), longer duration of symptoms before revision (P = 0.01), revision of a right eye (HR, 1.92; P = 0.03), and presumed preoperative infection (HR, 2.47; P = 0.04). In univariate analysis, success varied significantly by prior surgeon (P = 0.01), but not by revision surgeon. There was a 16% cumulative incidence of postoperative infection, with the highest risk in those with presumed preoperative infections (P = 0.01) and in persons of non-African, non-European derivation (P = 0.03).

CONCLUSIONS

The estimated rate of failure of tube shunt revision is 75% by 5 years, most often because of a need for further surgery. The major potentially modifiable feature associated with success is tube shunt revision being performed by the original surgeon.

Aqueous Drainage Device Erosion: A Review of Rates, Risks, Prevention, and Repair

Aqueous drainage device tube erosions require prompt intervention to prevent endophthalmitis. As the use of drainage devices in glaucoma surgery continues to increase, recognizing and managing tube erosions is a pertinent issue. This review provides a comprehensive overview of tube erosions, including the rates of erosion with various types of patch grafts, the risk factors associated with erosion, and approaches to repair in order to counsel and treat our patients to prevent endophthalmitis.

Measurement of Gamma-Irradiated Corneal Patch Graft Thickness After Aqueous Drainage Device Surgery

Importance

Exposure of the tube of an aqueous drainage device (ADD) through the conjunctiva is a serious complication of ADD surgery. Although placement of gamma-irradiated sterile cornea (GISC) as a patch graft over the tube is commonly performed, exposures still occur.

Objectives

To measure GISC patch graft thickness as a function of time after surgery, estimate the rate of graft thinning, and determine risk factors for graft thinning.

Design, Setting, and Participants

Cross-sectional study of graft thickness using anterior segment optic coherence tomography (AS-OCT) was conducted at the Wilmer Eye Institute at Johns Hopkins Hospital. A total of 107 patients (120 eyes, 120 ADDs) 18 years or older who underwent ADD surgery at Johns Hopkins with GISC patch graft between July 1, 2010, and October 31, 2016, were enrolled.

Intervention

Implantation of ADD with placement of GISC patch graft over the tube.

Main Outcomes and Measures

Graft thickness vs time after ADD surgery and risk factors for undetectable graft.

Results

Of the 107 patients included in the analysis, the mean (SD) age of the cohort was 64 (16.2) years, 49 (45.8%) were male, and 43 (40.2%) were African American. The mean time of measurement after surgery was 1.7 years (range, 1 day to 6 years). Thinner grafts were observed as the time after surgery lengthened (β regression coefficient, -60 µm per year since surgery; 95% CI, -80 µm to -40 µm). The odds ratio of undetectable grafts per year after ADD surgery was 2.1 (95% CI, 1.5-3.0; P < .001). Age, sex, race, type of ADD, quadrant of ADD placement, diagnosis of uveitis or dry eye, and prior conjunctival surgery were not correlated with the presence or absence of the graft.

Conclusions and Relevance

Gamma-irradiated sterile corneal patch grafts do not always retain their integrity after ADD surgery. Data from this cross-sectional study showed that on average, the longer the time after surgery, the thinner the graft. These findings suggest that placement of a GISC patch graft is no guarantee against tube exposure, and that better strategies are needed for preventing this complication.