Scanning Electron Microscopic Analysis of Biofilm Formation in Explanted Human Boston Type I Keratoprostheses.

PURPOSE: To describe the morphological distribution of host tissue and microbial biofilms on the intraocular surfaces of Boston type I keratoprostheses (KPros) explanted because of corneal melt. METHODS: Retrospective study of scanning electron microscopy (SEM) images from 4 explanted Boston type I KPros composed of polymethylmethacrylate and titanium. SEM images of KPro-associated ocular surfaces were reviewed for the presence of inflammatory cells, microbes, and/or biofilm formation. One sterile type I KPro was also imaged to serve as a (device only) control. RESULTS: All 4 KPros were explanted because of culture-negative, clinically "sterile" donor corneal melt with impending KPro extrusion. In all cases, the rough, irregular surfaces of the device harbored more adherent corneal epithelium and stromacytes, inflammatory cells, and bacteria than the smooth, polished surface of the KPro optic. Two KPros showed not only evidence of prior bacterial colonization but marked biofilm formation. CONCLUSIONS: SEM images of explanted KPros explanted for "sterile" corneal melt demonstrated evidence of biofilm formation despite negative donor corneal cultures and the absence of clinical suspicion for infection. These results suggest that "sterile" corneal melt may be due to inflammatory host responses to low microbial burdens as seen in biofilms and/or released antigens after antibiotic-induced lysis. There was increased adherence of host tissue cells and microbial biofilms on the nonpolished surfaces of the KPro. Polishing the intraocular polymethylmethacrylate and titanium KPro surfaces may decrease microbial adhesion and biofilm formation in human subjects with KPros, but what impact this will have on rates of postoperative endophthalmitis is unknown.

Image-guided femtosecond laser-assisted cataract surgery in Peters anomaly type 2.

UNLABELLED: We describe a technique for image-guided femtosecond laser-assisted cataract surgery in a case of Peters anomaly type 2. The femtosecond laser technology enabled reliable construction of a complete capsulotomy despite central corneal opacification and a tented anterior capsule. Use of an image-guided femtosecond laser for cataract extraction in Peters anomaly type 2 is a safe method for removing these complex cataracts while preserving capsular and corneal integrity. FINANCIAL DISCLOSURE: Dr. De la Cruz is a consultant to Alcon Surgical, Inc. No other author has a financial or proprietary interest in any material or method mentioned.

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.