Faculty Bibliography

Fuchs endothelial corneal dystrophy (FECD) is the most common indication for corneal transplantation in the United States, accounting 36% of the almost 47,000 transplants performed in 2016. Although the surgical management of FECD has undergone a revolution over the past 20 years, its pathogenesis remains elusive, with multiple putative disease pathways and an ever increasing number of candidate genes thought to play a role. This review will summarize the recent advancements in our understanding of the biology of FECD, including potential parallels with neurodegenerative disease like amyotrophic lateral sclerosis and will highlight prospects for future treatment advances.

PURPOSE/OBJECTIVE:To compare the outcomes of Boston keratoprosthesis type 1 implantation after failed keratoplasty in patients who are blind or sighted in the contralateral eye. METHODS:Retrospective comparative case series of Boston keratoprosthesis type I recipients performed for failed keratoplasty, between January 1, 2008, and June 30, 2016, at a single center. Patients were divided based on the best-corrected visual acuity in the contralateral eye at the time of surgery: group I, ≤20/200, and Group II, >20/200. Preoperative diagnoses, postoperative visual acuity, device retention, and postoperative complications were compared. RESULTS:Group I (37 eyes) and group II (36 eyes) had similar demographics, median preoperative best-corrected visual acuity (count fingers) in the operated eye, and median duration of postoperative follow-up (37.4 vs. 45.2 months, respectively). Keratoprosthesis retention after the first year postimplantation was significantly better in group I versus group II (P = 0.038). Sterile vitritis and sterile keratolysis occurred more frequently in group II compared with group I (P = 0.013 and P = 0.056, respectively). At final examination, visual outcomes were not significantly different between the 2 groups. CONCLUSIONS:Most patients with failed keratoplasty who were implanted with a Boston keratoprosthesis type I experienced improved vision, and visual acuity of the contralateral eye did not seem to influence the visual outcome of surgery. However, patients with good vision in the contralateral eye were more likely to experience complications, possibly because of reduced vigilance when the other eye has ambulatory vision.

OBJECTIVES/OBJECTIVE:To examine clinical outcomes of oversized titanium back plates in type I Boston keratoprosthesis (KPro) implantation. METHODS:Retrospective study of 22 sequential eyes (20 patients) undergoing type I KPro implantation with an oversized titanium back plate (larger than trephined wound diameter by 1.0 mm or more), performed by a single surgeon (K.A.C.) from June 2010 to November 2014. Data were collected regarding preoperative eye characteristics, surgical details, and postoperative clinical outcomes. RESULTS:Mean follow-up time per eye was 24.1±14.9 months. All eyes had improved vision after surgery; 13 eyes (59.1%) maintained visual acuity improvement at last follow-up. Initial KPro's were retained in 19 eyes (86.4%); one eye required KPro replacement. Primary retroprosthetic membrane (RPM) developed in three eyes (13.6%), with similar occurrence in aniridic (14.3%) and nonaniridic eyes (13.3%). Secondary RPM's developed in two eyes (9.1%) after vitritis (one eye) and retinal and choroidal detachment (one eye). Glaucoma was a common comorbidity: 2 of 14 eyes (14.3%) with preoperative glaucoma had glaucoma progression, and 4 of 8 eyes (50.0%) without preoperative glaucoma developed glaucoma postoperatively. Other postoperative complications included retinal detachment (5 eyes, 22.7%) and idiopathic vitritis (3 eyes, 13.6%). CONCLUSIONS:Oversized titanium KPro back plates are associated with a low rate of primary RPM formation and may have particular utility in reducing primary RPM formation in aniridic eyes. Glaucoma remains a challenge in postoperative KPro management. Complex eyes, at increased risk of postoperative complications, require careful management.

OBJECTIVES/OBJECTIVE:To describe the postmortem histologic features after an unsuccessful Descemet membrane endothelial transfer (DMET) and assess any potential clinical implications. METHODS:Postmortem, an eye from a patient who previously underwent unsuccessful DMET for pseudophakic bullous keratopathy (PPBK) was harvested and processed for morphologic evaluation. RESULTS:Clinically and histologically, the host cornea showed evidence of diffuse stromal edema. Although the edges of the surgical descemetorhexis were well visualized, there was no evidence of endothelial migration or repopulation of the posterior stroma from any direction. A multilayered, retrocorneal membrane was present that appeared to originate from the trabecular meshwork. CONCLUSIONS:Descemet membrane endothelial transfer and "descemetorhexis alone" may be insufficient treatment for eyes operated on for PPBK, that is, eyes with a significantly depleted or dysfunctional endothelium.

PURPOSE/OBJECTIVE:To propose a new treatment paradigm for chemical burns to the eye - in the acute and chronic phases. METHODS:Recent laboratory and clinical data on the biology and treatment of chemical burns are analyzed. RESULTS:Corneal blindness from chemical burns can now be successfully treated with a keratoprosthesis, on immediate and intermediate bases. Long term outcomes, however, are hampered by early retinal damage causing glaucoma. New data suggest that rapid diffusion of inflammatory cytokines posteriorly (TNF-α, etc) can severely damage the ganglion cells. Prompt anti-TNF-α treatment is markedly neuroprotective. Long term profound reduction of the intraocular pressure is also vital. CONCLUSION/CONCLUSIONS:A new regimen, in addition to standard treatment, for severe chemical burns is proposed. This involves tumor necrosis factor alpha (TNF-α) inhibition promptly after the accident (primarily for retinal neuroprotection), prophylactic maximal lowering of the intraocular pressure (starting immediately), and keratoprosthesis implantation in a later quiet state.

PURPOSE/OBJECTIVE:To quantitatively evaluate the angle anatomy in eyes with the Boston type I keratoprosthesis (B-KPro) differing in the back plate (BP) material and size using anterior segment optical coherence tomography. METHODS:B-KPro eyes with poly(methyl methacrylate) (PMMA) (7.0 and 8.5 mm) and titanium (7.0, 8.5, and 9.5 mm) BPs were imaged with anterior segment optical coherence tomography. The angle opening distance at 500 μm from the scleral spur (AOD500), trabecular iris surface area at 500 μm from the scleral spur (TISA500), and trabecular iris angle at 500 μm from the scleral spur (TIA500) were measured. Among the visible quadrants, the average, the temporal, the widest, and the narrowest angle of each eye were included in the analysis. Average time between B-KPro implantation and imaging was 7.5 ± 1.4 years for a PMMA BP and 2.4 ± 2.3 years for a titanium BP (P < 0.0001). RESULTS:We analyzed 17 B-KPro eyes with PMMA BPs and 24 B-KPro eyes with titanium BPs. The average AOD500 (394.1 ± 226.9 vs. 454.5 ± 255.6 μm, P = 0.44), average TIA500 (26.2 ± 14.2 vs. 29.8 ± 13.9 degrees, P = 0.43), and average TISA500 (0.15 ± 0.08 vs. 0.17 ± 0.10 μm, P = 0.52) were not statistically different between eyes with PMMA and titanium BPs, nor were the temporal, the narrowest, and the widest angle measurements of each eye (all P > 0.05). Similarly, no significant differences were found between the angle measurements of B-KPro eyes with a titanium BP diameter of 8.5 or 9.5 mm (all P > 0.05). CONCLUSIONS:We successfully visualized the angle anatomy in 66.1% of the imaged eyes, including all BPs studied. Neither the material nor the size of the B-KPro BP had a significant impact on the angle anatomy.

PURPOSE/OBJECTIVE:To describe the clinical course, surgical experience, and postoperative outcomes of 3 patients with Fuchs endothelial dystrophy who underwent Descemet membrane endothelial keratoplasty (DMEK) after failed Descemet stripping without endothelial keratoplasty. METHODS:Three patients who underwent DMEK for management of persistent corneal edema after deliberate Descemet stripping in the setting of Fuchs endothelial dystrophy were identified. Patients were examined at day 1, week 1, and months 1, 3, and 6 after DMEK. Visual acuity, central corneal thickness (CCT), and evaluation of central corneal endothelial cell counts were recorded. RESULTS:Two women and one man, aged 56, 72, and 68 years, were included. The time interval between primary Descemet stripping and DMEK ranged from 3.5 to 8 months. Preoperative visual acuities were 20/200, 20/300, and 20/80. Immediately before DMEK, no patients had countable central endothelial cells, and CCTs were 825, 1034, and 878 μm. After DMEK, all patients had improvement in visual acuity to 20/70, 20/20, and 20/20 with CCTs of 529, 504, and 528. The postoperative period in the first case was notable for the immediate development of a pigmented pupillary membrane with posterior synechiae, as well as cystoid macular edema, of uncertain chronicity, noted 1 month postoperatively. The second case also developed posterior synechiae. Two cases completed 6-month endothelial cell counts totaling 2200 and 3114 cells per square millimeter (endothelial cell loss of 13% and 5.3%). CONCLUSIONS:DMEK is a reliable procedure to facilitate corneal rehabilitation and visual recovery in the event of poor corneal clearance after Descemet stripping without endothelial keratoplasty.