Jose de la Cruz

Visual outcomes of Boston keratoprosthesis implantation as the primary penetrating corneal procedure.

Purpose: To report the short-term visual outcomes and complications of keratoprosthesis surgery as the primary penetrating corneal procedure for patients at high risk for conventional corneal transplantation. Methods: A retrospective chart review was conducted of 21 eyes of 19 patients who underwent either Boston keratoprosthesis type I or type II as the primary penetrating corneal procedure from February 2007 to March 2011. Results: Nineteen type I (90.5%) and 2 type II (9.5%) Boston keratoprosthesis procedures were performed in 19 patients. Mean follow-up was 14.6 months (range, 6–36.3 mo). Primary indications for surgery included chemical or thermal injury, aniridia, and Stevens–Johnson syndrome. Preoperative best-corrected visual acuity (BCVA) ranged from 20/100 to light perception and was count fingers or worse in 20 eyes (95.2%). At last follow-up for all eyes, 15 eyes (71.4%) achieved BCVA ≥20/200 and 4 eyes (19%) improved to BCVA ≥20/50. No intraoperative complications occurred. Postoperative complications include retroprosthetic membrane formation (47.6%), cystoid macular edema (33.3%), elevated intraocular pressure (23.8%), glaucoma progression (14.3%), and endophthalmitis (4.8%). The initial keratoprosthesis was retained in 19 eyes (90.5%). Conclusion: The Boston keratoprosthesis, based on early follow-up, is a good alternative as a primary penetrating corneal procedure in a select group of patients with very poor prognosis for penetrating keratoplasty. Although complications can occur and require close monitoring, visual acuity significantly improved in the majority of patients.

Retroprosthetic Membrane and Risk of Sterile Keratolysis in Patients With Type I Boston Keratoprosthesis

PURPOSE To evaluate whether retro-backplate retroprosthetic membrane is correlated with risk of melt in patients with a type I Boston Keratoprosthesis (KPro). DESIGN Retrospective, observational case series. METHODS Study of 50 eyes of 47 patients with type I Boston KPro and postoperative anterior segment optical coherence tomography (AS OCT) imaging performed at the University of Illinois at Chicago. Main outcome measures were presence of retro-backplate membrane and development of melt requiring explantation. For eyes with melt, membrane thickness was measured using the AS OCT images obtained at the last visit before melt occurred. For eyes without melt, the last available AS OCT images were used for measurement. RESULTS AS OCT evidence of a retro-backplate membrane was observed in 100% of eyes that melted and in 34.1% of eyes that did not (P = .0034; risk ratio, 2.9; 95% confidence interval, 1.9 to 4.4). Retro-backplate membrane thickness in the melt group was 278 μm versus 193 μm in the nonmelt group (P = .025). CONCLUSIONS The retro-backplate portion of a retroprosthetic membrane is to be differentiated from the retro-optic portion seen at the slit lamp. The retro-backplate membrane as shown by AS OCT imaging is correlated with an increased risk of sterile keratolysis, possibly because of impedance of nutritional support from the aqueous humor. Further studies are needed to better standardize the AS OCT measurements of retro-backplate membranes as well as to identify early interventions to prevent progression of thin membranes once identified on AS OCT.

Imaging implanted keratoprostheses with anterior-segment optical coherence tomography and ultrasound biomicroscopy.

Purpose: To describe the anterior ocular segment findings of eyes with implanted Boston type 1 keratoprostheses (KPro) in vivo by using anterior-segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM). Methods: A retrospective, comparative study was made of patients with implanted KPros who were examined with AS-OCT (AC Cornea OCT) and UBM (OTI Scan 35-50MHz Ultrasound). Results: One pseudophakic and 1 aphakic eye were included in the study. Cross-sectional AS-OCT adequately imaged the components of the KPro (front plate with stem, back plate, and titanium ring), the corneal graft, and host cornea. The angles could be seen as open, filled with debris, or closed. Coronal AS-OCT showed en face views of each KPro part. Retrokeratoprosthetic membranes were depicted to be thick opacities covering the rear optical surface of the stem. UBM, on the other hand, imaged the KPro front plate as a muffin-shaped space at the apical center, with the corneal graft appearing wispy and the host cornea grainy. The back plate, titanium ring, and angles could not be resolved. Glaucoma tubes and posterior-chamber intraocular lens (PCIOL) haptics were imaged below the iris plane. Conclusions: Cross-sectional AS-OCT adequately imaged the components of the assembled KPro in vivo, as well as its interaction with surrounding anterior-segment structures. It allowed visualization of the anterior chamber, iris, and angle, essential in the postoperative care of these patients. Coronal AS-OCT showed graphic en face images of the KPro device and suspected retrokeratoprosthetic membranes. UBM, on the other hand, adequately imaged glaucoma tube shunts and PCIOL haptics beneath the iris plane.

Serial Analysis of Anterior Chamber Depth and Angle Status Using Anterior Segment Optical Coherence Tomography After Boston Keratoprosthesis.

Purpose: To analyze iris behavior and angle status using serial anterior segment optical coherence tomography (AS-OCT) after Boston keratoprosthesis (KPro). Methods: A prospective cases series consisted of 11 eyes with implanted type 1 KPro at a tertiary care institution. The patients underwent preoperative and serial postoperative AS-OCT imaging. The main outcome measures included anterior chamber angle (ACA) at representative meridians (0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees), grading of total ACA as open (>10 degrees), shallow (≥1 degrees and ⩽10 degrees) or closed (<1 degrees), preoperative anterior chamber depth (ACD), postoperative anatomical and functional ACD, and the presence of iris-back plate touch and peripheral anterior synechiae. Results: The mean follow-up with serial AS-OCT was 13.1 months. Preoperatively, 54.5%, 27.3%, and 18.2% of the eyes had open, shallow, and closed angles, respectively. The mean change in the effective ACD decreased postoperatively by 1.61 mm. At 0 degree and 180 degree meridians, the ACA decreased by a mean change of 6.95 degrees and 8.40 degrees, with a mean change of 8.12 degrees for all meridians. Eight (72.7%) eyes had synechiae with 7.3 and 6.7 clock hours of peripheral anterior synechiae and iris-back plate touch. At the last follow-up, 7 (63.6%) eyes had considerable progression of angle closure (change in grading of total angle), and 18.2%, 36.4%, and 45.5% had open, shallow, and closed angles, respectively. Conclusions: KPro implantation induced progressive angle closure, shallowing of the anterior chamber, and synechiae formation that is not visible on clinical examination. Serial AS-OCT plays an important role in the detection and monitoring of progressive angle closure, and clinical correlation is needed to assess the association with glaucoma development or progression.

Special considerations for pars plana tube-shunt placement in Boston type 1 keratoprosthesis.

The Boston type 1 keratoprosthesis has been successfully used in eyes with a poor prognosis for a conventional penetrating keratoplasty. The Boston Type 1 Keratoprosthesis Study Group reported significant postoperative vision improvement with a high rate of graft retention. However, glaucoma has significantly limited visual potential in patients with otherwise successful transplants. Given a crowded anterior chamber, scarring, and/or inability to visualize the anterior segment after the keratoprosthesis implantation, vitrectomy and pars plana tube placement is frequently necessary for intraocular pressure control. In addition, the need for optimal contact lens fitting after surgery necessitates a modified surgical technique for the combined procedure to avoid complications and to achieve optimal visual rehabilitation. We present our technique in a case series of combined vitrectomy and pars plana glaucoma shunt placement for the Boston type 1 keratoprosthesis.

Outcomes of boston keratoprosthesis implantation for failed keratoplasty after keratolimbal allograft

Purpose: To evaluate factors that contribute to keratoplasty failure after keratolimbal allograft (KLAL) and report the outcomes of Boston keratoprosthesis type I (KPro) as salvage therapy. Methods: Retrospective noncomparative case series of 7 eyes in 7 consecutive patients with ocular surface disease and limbal stem cell deficiency treated with KPro after failed KLAL. Mechanisms of graft failure, KPro device retention rate, and preoperative and postoperative best-corrected visual acuities were studied. Results: In the studied cohort, keratoplasty graft failure occurred at an average of 9.9 months (range, 1–17 months) after KLAL. Among the 7 eyes reviewed, 4 had tube shunts, 3 of which contributed directly to endothelial graft failure. One eye failed due to fungal keratitis, 1 eye failed due to immune-mediated endothelial rejection, and 2 eyes failed due to recurrent surface disease. During an average follow-up of 585 days (19.5 months) after KPro, best-corrected visual acuity improved from a median of counting fingers CF@2ft (range, hand motions to 20/400) to a median of 20/400 (range, CF@3ft to 20/25). There was 85.7% (6 of 7) retention of implanted devices at the last follow-up, with 1 eye requiring repeat KPro for corneal melt and implant extrusion after abrupt cessation of immunosuppression. Conclusions: Despite successful KLAL outcomes and systemic immunosuppression, patients who undergo ocular surface reconstruction with KLAL are still at risk for subsequent keratoplasty failure. Keratoprosthesis is a viable salvage therapy for visual rehabilitation in these patients. Adequate immunosuppression is important in postoperative management of these patients.

Anterior Segment Optical Coherence Tomography for the Quantitative Evaluation of the Anterior Segment Following Boston Keratoprosthesis

Objective To quantitatively evaluate the anterior segment using anterior segment optical coherence tomography (AS-OCT) following Boston keratoprosthesis type 1. Methods A retrospective study consisted of AS-OCT imaging at a single time point postoperatively in 52 eyes. Main outcomes measures include anatomical and functional anterior chamber depth (ACD), angle (ACA) and peripheral and proximal synechiae. Results The mean time point of imaging was 19.3 months postoperatively. Average anatomical and functional ACD was 2.0 and 0.21 mm respectively, and mean ACA ranged from 2.5° to 6.14° in representative meridians. An average of 8.7 clock hours of angle closure was observed in the 25 eyes in which all meridians were imaged. The majority of eyes showed peripheral (86.5%) and proximal (67.3%) synechiae. Conclusions AS-OCT is a useful tool for quantitative evaluation of anterior segment and angle after keratoprosthesis, which is otherwise poorly visible. The majority of eyes showed shallow ACD, extensive angle closure and synechiae formation.

Contact lens surveillance cultures in boston type 1 keratoprosthesis patients

Objectives: To describe surveillance cultures of bandage contact lenses (BCL) in patients with a history of Boston type 1 keratoprosthesis (KPro) surgery. Methods: An institutional review board–approved retrospective review of patients with a history of Boston type 1 KPro surgery and BCL cultures between July 2008 and June 2010. Data on demographics, preoperative diagnosis, topical corticosteroid and antibiotic use, duration of BCL wear, clinical diagnosis of microbial keratitis or endophthalmitis, and culture results were recorded. Results: There were 14 patients (15 eyes) who underwent Boston type 1 KPro between July 2008 and June 2010 with BCL culture data. Ten eyes showed positive growth and one eye developed an infection. Thirty-four cultures were performed and 12 were positive. The most common organism cultured was coagulase-negative staphylococcus (CoNS). Positive cultures, colonization by non-CoNS pathogens, and infection occurred more frequently in patients with an ocular history of autoimmune disease or chemical burn. The growth of 15 or more CoNS colonies occurred only in patients not on vancomycin. An antibiotic was added to the regimen in response to positive cultures for three patients. Conclusions: Contact lens surveillance cultures may provide valuable information on the characteristics of microbial colonization, particularly in highlighting inflammatory disease and disuse of vancomycin as possible risk factors. Bandage contact lenses cultures also have the potential to be useful adjuncts in the clinical management of antibiotic therapy.

Outcomes of pars plana glaucoma drainage implant in Boston type 1 keratoprosthesis surgery.

Purpose:Glaucoma drainage implantation in conjunction with Boston Type 1 Keratoprosthesis placement is a surgical option in controlling postoperative glaucoma. The purpose of this study is to report outcomes of combined pars plana vitrectomy and glaucoma drainage implantation with corneal patch graft in Boston Type 1 Keratoprosthesis patients. Patients and Methods:A retrospective review of patients who underwent pars plana glaucoma drainage implantation in combination with Boston Type 1 Keratoprosthesis was performed. Preoperative and postoperative parameters collected and analyzed included: visual acuity, intraocular pressure, number of glaucoma medications to achieve intraocular pressure control, bandage contact lens fit, and postoperative complications. Results:Twenty eyes of 20 patients were identified; 95% had preoperative diagnosis of glaucoma, utilizing on an average 2.5 medications with an average intraocular pressure of 19.8 mm Hg (±6.3 mm Hg; range, 9 to 32.8 mm Hg). After placement of the pars plana glaucoma drainage implant, an average intraocular pressure of 19 mm Hg (±7.0 mm Hg; range, 8 to 30 mm Hg) by scleral pneumotonometry was achieved and 85% were deemed to have normal pressures by digital palpation. An average of 2.1 intraocular pressure-lowering medications were required on last follow-up. Average follow-up was 31.6 months (±17.4 mo; range, 12.3 to 71.6 mo). Two eyes required glaucoma drainage implant explantation: one eye due to endophthalmitis from a nonhealing corneal ulcer and the other eye due to corneal melt. None of our patients experienced conjunctival erosion over a pars plana positioned glaucoma drainage implant or tube. Conclusions:For the long-term management of glaucoma in keratoprosthesis patients, a posteriorly placed pars plana glaucoma drainage implant with corneal patch graft in conjunction with keratoprosthesis has a low risk of erosion and postoperative complications.

Histopathological and Immunohistochemical Analysis of Melt-Associated Retroprosthetic Membranes in the Boston Type 1 Keratoprosthesis

IMPORTANCE Retroprosthetic membrane (RPM) formation is the most common complication associated with the Boston type 1 keratoprosthesis and has been associated with corneal melt. OBJECTIVE To identify the histological and immunohistochemical characteristics of RPMs associated with corneal melt. DESIGN, SETTING, AND PARTICIPANTS Observational histopathological case series at a tertiary eye care referral center among patients who underwent Boston type 1 keratoprosthesis explantation because of donor corneal melt at the Illinois Eye and Ear Infirmary between January 1, 2011, and January 1, 2012. EXPOSURES Seven RPM specimens from 7 eyes were stained with hematoxylin-eosin, cytokeratin 7, cytokeratin AE1/3, smooth muscle actin, vimentin, and CD34. Light microscopy was used to evaluate specimens for inflammation and epithelial ingrowth. XY-karyotyping using fluorescence in situ hybridization was performed on 4 specimens with known donor-recipient sex mismatch. MAIN OUTCOMES AND MEASURES Histological and immunohistochemical characteristics of RPMs. RESULTS Inflammatory cells were present in 4 of 7 RPMs. In 3 of 4 sex-mismatched specimens, tissue XY-karyotyping of the RPM interphase cells was consistent with the host sex karyotype. The fourth specimen showed a mixture of recipient-type and donor-type cells. CONCLUSIONS AND RELEVANCE Melt-associated RPMs show variable degrees of inflammation. Most membranes seem to originate from a proliferation of host cells, but donor tissue may contribute in some cases.