A safe Nd:YAG retroprosthetic membrane removal technique for keratoprosthesis

Incidence, risk factors, and treatment of retroprosthetic membranes following Boston keratoprosthesis eyes and the impact of glaucoma surgery

PURPOSE

To assess incidence, risk factors, and treatment of retroprosthetic membrane (RPM) formation in eyes following Boston keratoprosthesis (Kpro) implantation and their correlation with glaucoma drainage device placement (GDD).

METHODS

A retrospective review was performed on eyes that underwent Kpro type I or II implantation between 2005 and 2020 at a tertiary academic center. Multiple variables were collected including preoperative characteristics, presence of RPM, management of RPM, and outcomes including corrected visual acuity (VA). A Fischer's exact test was used to evaluate the significance of risk factors of RPM formation and an odds ratio was calculated for each possible risk factor. A Mann-Whitney U test was used to evaluate comparisons between outcomes and qualitative analyses.

RESULTS

Of the 87 eyes identified, 37 (43%) developed an RPM within an average of 1.5 years (range, 31 days-7.5 years) following Kpro implantation. Mean follow-up duration was 4.3 years. Eyes that developed RPM had significantly worse preoperative VA compared to those that did not (logMAR 2.55 vs. 2.28, p = 0.022). The mean number of prior penetrating keratoplasty procedures trended higher in eyes that developed RPM (2.46 vs. 2.18, p = 0.44) but was not significant. GDD placement after Kpro implantation was associated with an increased risk of RPM formation (RR = 1.69 p = 0.026). Of the 37 eyes that developed an RPM following Kpro, 17 (47%) were treated with Nd:YAG laser, and four of those 17 (21%) also underwent pars plana vitrectomy (PPV). Seven of 37 eyes (19%) underwent PPV without Nd:YAG. Comparisons between RPM occurrence and final VA were not significant.

CONCLUSIONS

The incidence of RPM formation following Kpro implantation was 43%. Eyes that developed RPM had significantly worse preoperative VA. GDD placement after Kpro implantation increased the risk of developing RPM. Final VA and occurrence of RPM were not significantly different between the Nd:YAG and PPV treatment groups.

Implantable self-aligning fiber-optic optomechanical devices for in vivo intraocular pressure-sensing in artificial cornea

Artificial cornea is an effective treatment of corneal blindness. Yet, intraocular pressure (IOP) measurements for glaucoma monitoring remain an urgent unmet need. Here, we present the integration of a fiber-optic Fabry-Perot pressure sensor with an FDA-approved keratoprosthesis for real-time IOP measurements using a novel strategy based on optical-path self-alignment with micromagnets. Additionally, an alternative noncontact sensor-interrogation approach is demonstrated using a bench-top optical coherence tomography system. We show stable pressure readings with low baseline drift (<2.8 mm Hg) for >4.5 years in vitro and efficacy in IOP interrogation in vivo using fiber-optic self-alignment, with good initial agreement with the actual IOP. Subsequently, IOP drift in vivo was due to retroprosthetic membrane (RPM) formation on the sensor secondary to surgical inflammation (more severe in the current pro-fibrotic rabbit model). This study paves the way for clinical adaptation of optical pressure sensors with ocular implants, highlighting the importance of controlling RPM in clinical adaptation.

No Light Perception Outcomes Following Boston Keratoprosthesis Type 1 Surgery

PURPOSE

To determine the incidence rate, principal causes, and clinical course of eyes developing no light perception (NLP) visual acuity (VA) following Boston Keratoprosthesis (B-KPro) type 1 surgery. Secondary objectives include determining the incidence rate, relative risk (RR), and survival probability with respect to NLP outcomes among eyes with congenital aniridia.

DESIGN

Retrospective, interventional case series.

SUBJECTS

All patients undergoing B-KPro type 1 surgery between October 2008 and June 2016 by a single surgeon at CHUM - Hôpital Notre-Dame.

METHODS

Records of patients having undergone B-KPro implantation were reviewed. Eyes with a final outcome of NLP were further reviewed to determine best recorded postoperative VA, time to NLP onset, clinical course, and principal cause. Descriptive statistics, incidence rates, Kaplan-Meier survival curves, and the RR of NLP outcomes among eyes with aniridia were determined. Statistical significance was defined as P < .05.

RESULTS

Records of 119 patients were included, with an average follow-up of 49.1 ± 26.8 months postoperatively. Nineteen eyes had a final outcome of NLP, representing 16.0%. The incidence rate of NLP was 0.04 cases per eye-year of follow-up. The most common principal causes were inoperable retinal detachment (n = 7, 36.8%), terminal glaucoma (n = 6, 31.6%), and carrier graft melt-related complications (n = 5, 26.3%). The RR of developing NLP among eyes with aniridia was 3.04 (P = .01).

CONCLUSIONS

No light perception is a devastating but uncommon outcome of B-KPro surgery. Patients with aniridia seem to be at increased risk. In spite of all available medical and surgical interventions, some eyes may still suffer this outcome.

Randomized controlled trial comparing Nd:YAG laser photocoagulation and bipolar electrocautery in the management of epistaxis

The objective of this study is to evaluate the efficacy and degree of comfort of Nd:YAG laser photocoagulation compared to bipolar electrocautery in the management of epistaxis. Seventy-two consecutive patients with a history of epistaxis were randomly assigned to receive treatment in an outpatient setting consisting of either bipolar electrocautery (group 1) or Nd:YAG laser photocoagulation (group 2). The study was conducted in university-affiliated teaching hospital. Seventy-two consecutive patients who suffered from anterior epistaxis and presented to the Otolaryngology Department at the Eye, Ear, Nose and Throat Hospital, Fudan University, between June 2015 and August 2015. The following outcome measures were assessed: bleeding intensity, bleeding frequency 4 and 16 weeks after treatment (0 = no bleeding, 1 = reduced bleeding, 2 = the same, and 3 = worse), participant perception of discomfort during treatment (grade 0-10, where 10 is the worst pain), and therapy duration and complications. At 16 weeks, 91% of the laser patients versus 91% of the bipolar electrocautery patients had no reported bleeding. The outcome scores at 4 and 16 weeks after treatment showed no significant difference between the two groups (P = 0.5 and P = 0.98, respectively; P > 0.05). The median pain levels experienced during the office laser and bipolar electrocautery procedures were 3.0 and 4.0, respectively, and the median durations of the laser and electrocautery therapies were 3.0 and 4.0, respectively. Neither groups had complications. It can be concluded that Nd:YAG laser photocoagulation and bipolar electrocautery are both effective in the treatment of epistaxis. These two therapies are recommended. As a whole, these two therapies, performed in an office setting, are timely, efficacious, and well tolerated in the treatment of epistaxis.

Vitreoretinal complications of the Boston Keratoprosthesis

The Boston Keratoprosthesis has allowed for visual restoration in patients with corneal blindness; however, vitreoretinal complications remain a significant cause of ocular morbidity. Retroprosthetic membranes, infectious endophthalmitis, sterile vitritis, vitreous hemorrhage, vitreous opacities, retinal detachment, cystoid macular edema, choroidal detachments, retinal vascular occlusion, and epiretinal membrane have all been described, may require the intervention of a vitreoretinal specialist, and are reviewed herein. A strong familiarity with associated posterior segment complications is important to maximizing patient outcomes.

Medium-term outcomes of boston type 1 keratoprosthesis implantation in Bangkok, Thailand

PURPOSE

The aim of this study was to investigate the medium-term outcomes after Boston type 1 keratoprosthesis surgery in patients with poor prognosis for standard keratoplasty.

METHODS

A prospective study of a case series was conducted at a university-based referral center from 2006 to 2013. Forty-two eyes of 40 patients with a minimum follow-up of 4 years were recruited. The main outcome measures included best spectacle-corrected visual acuity (BSCVA), keratoprosthesis retention, and complications.

RESULTS

The mean follow-up was 64.9 ± 15.2 months (range, 48-88 months). At 1 week, 90.5% had an improvement in BSCVA by ≥2 lines compared with that in preoperative BSCVA. The best-ever vision was reached by the end of 6 months. Nevertheless, 39.5% (15/38) could not maintain the improved vision. The major etiology of visual deterioration after initial gains was glaucoma (60%). The initial keratoprosthesis retention rate was 80.9%, corresponding to a failure rate of 4 per 100 eye-years or 0.04/eye-year. Autoimmune diagnosis was the independent risk factor for keratoprosthesis failure (hazard ratio, 5.68; 95% confidence interval, 1.41-22.85; P = 0.014). The common postoperative complications were glaucoma, retroprosthetic membrane, corneal melting, infectious keratitis, and endophthalmitis.

CONCLUSIONS

Boston type 1 keratoprosthesis is an alternative for patients who are not candidates for corneal transplants. However, there was a trend toward visual loss over time most commonly because of progressive glaucoma. Therefore, appropriate patient selection, lifelong follow-up, and early aggressive treatment of complications are recommended.

Retinal detachments after Boston Keratoprosthesis: incidence, predisposing factors, and visual outcomes

PURPOSE

To determine the rates, predisposing factors, and visual outcomes of retinal detachment (RD) after Boston Keratoprosthesis (KPro) implantation.

METHODS

In this noncomparative, interventional case series, the medical records of 170 patients (205 eyes) who underwent Boston type 1 and type 2 KPro implantation at the Massachusetts Eye and Ear Infirmary between April 1993 and June 2009 were retrospectively reviewed. Incidence and annual rates of RD were calculated, and the roles of possible predictive factors for RD after KPro were investigated. Main outcome measures were rates of and risk factors for RD, visual acuity after RD, and surgical outcomes after repair.

RESULTS

Sterile vitritis and autoimmune systemic disease significantly predisposed patients to RD after KPro placement. Of patients who developed RD after implantation, 50% progressed to visual acuity of no light perception despite surgical repair.

CONCLUSIONS

Inflammation plays a major role in RD development after KPro implantation. Patients with predisposing factors should be advised of the high rates of RD and comanaged with a vitreoretinal specialist.

Neodymium-yttrium-aluminum-garnet laser lysis of retained cortex after phacoemulsification cataract surgery

PURPOSE

To describe the use of the neodymium-yttrium-aluminum-garnet (Nd:YAG) laser to lyse residual cortex after phacoemulsification cataract surgery and report the complications and outcomes of treatment.

DESIGN

Interventional, retrospective case series.

METHODS

Consecutive patients who underwent Nd:YAG laser treatment for residual cortex at the Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan were identified by review of laser logs from 2005 to 2011. The medical records were reviewed, and the course and complications of treatment were recorded. The main outcome measures were improvement in subjective vision and corrected distance visual acuity.

RESULTS

Eighteen eyes of 18 patients, mean age 66 ± 11 years, were included. Eight eyes (44%) had intraoperative posterior capsule rupture. Before treatment with the Nd:YAG laser, all patients had subjective visual complaints, with 6 patients reporting counting fingers or worse visual acuity. Eleven patients (61%) were successfully treated with 1 session of cortical lysis, while 5 patients underwent 2 and 2 patients underwent 3 or more treatments. Five patients (28%) had elevated intraocular pressure (IOP) within 1 day of treatment, and 1 patient developed cystoid macular edema. All patients had resolution of subjective visual symptoms, and at final follow-up corrected distance acuity was 20/25 or better in 13 patients (72%).

CONCLUSIONS

The Nd:YAG laser can be used to lyse residual cortex after uncomplicated cataract surgery or cases with intraoperative posterior capsular rupture, and results in an improvement in subjective and corrected distance visual acuity. Elevated IOP is a common complication.

Post-surgical visual outcome and complications in Boston type 1 keratoprosthesis

OBJECTIVE

To describe the visual outcome of patients who underwent Boston type 1 keratoprosthesis (KPro1) implantation, and describe serious sight-threatening post-operative complications.

METHODS

We performed an analysis of the clinical records of all patients who underwent Boston keratoprosthesis implantation (BKI)in our institution from May 2006 to February 2011.

RESULTS

A total of 41 eyes of 37 patients were included in the final analysis, of whom 22 (59.45%) were male and 15 were (40.54%) female. The mean age was 56.44 years (range 2-90). The most frequent diagnoses were bullous keratopathy, autoimmune diseases, such as Stevens-Johnson syndrome (SJS)/Lyell syndrome (LS), and aniridic keratopathy. The mean number of previous keratoplasties (PK) was 2.36 (range 0-8), the mean number of previous non-PK surgeries was 1.58 (range 0-9). The mean follow-up time was 22.17 months (range 3-46). The mean best corrected visual acuity (BCVA) logMAR before surgery was 2.05 (range 1.10-2.52), and the mean best corrected visual acuity achieved after surgery was 1.16 (range 0.08- 2.70). The most frequent complication was the formation of retroprosthetic membrane (RPM) which appeared in 22 (53.65%) eyes. Of these, 6 (27.27%) appeared after another surgery. Fourteen (63.63%) RPM required treatment, an average of 1.71 (range 1-4) laser YAG applications were performed, and surgical membranectomy was performed in 3 patients. Eleven (26.82%) eyes showed chorioretinal adhesion problems, 6 (14.63%) of which occurred after follow-up of BKI surgery. Infectious complications occurred in 7 (17.07%) cases; 2 (4.87%) patients had infectious keratitis and 5 (12.19%) endophthalmitis.

CONCLUSIONS

Visual function improved in most patients. Those with prior multiple ocular surgeries and alterations of systemic immunity such as SJS, LS, and diabetes mellitus are at increased risk for serious sight-threatening complications, such as RPM, chorioretinal detachment and infection. Nevertheless, we consider KPro as an effective alternative in patients with multiple ocular pathology and imminent risk of rejection of a new KP.

Boston type 1 keratoprosthesis: the New York Eye and Ear experience

PURPOSE

The Boston keratoprosthesis has had variable success rates in the past. However, significant modifications to design and management have recently led to successful outcomes. This study was undertaken to evaluate the outcomes of the Boston type 1 keratoprosthesis at our institution.

METHODS

A retrospective chart review was performed of all Boston type 1 keratoprosthesis procedures conducted at a single practice at the New York Eye and Ear Infirmary from December 2006 to August 2010. Outcome measures included visual acuity, retention rates, and complications.

RESULTS

In all, 58 eyes of 51 patients who received a Boston type 1 keratoprosthesis were included. The most common indication for the keratoprosthesis was failed penetrating keratoplasty (PK) (81.0%; mean 2.4±1.3 PKs per eye). Glaucoma was the most common comorbidity (75.9%). Pre-operative best corrected visual acuity (BCVA) was <20/400 in 87.9% of eyes. At last follow-up, 43.1% of eyes had a BCVA of 20/200. Retention rate was 87.9% over an average follow-up of 21.5±11.4 months (median 22 months, range 3-47 months). Complications increased with time, with 65.5% of eyes experiencing at least one event by 6 months and 75.9% by 1 year. The most common post-operative complication was retroprosthetic membrane formation (50.0%).

CONCLUSIONS

The Boston type 1 keratoprosthesis provides visual recovery for eyes with multiple PK failures or with poor prognosis for primary PK, showing excellent retention rates. However, there is a trend towards a decline in visual acuity with time and the development of late complications, highlighting a need for longer-term studies.