Cell Types of the Human Retina and Its Organoids at Single-Cell Resolution.

Human organoids recapitulating the cell-type diversity and function of their target organ are valuable for basic and translational research. We developed light-sensitive human retinal organoids with multiple nuclear and synaptic layers and functional synapses. We sequenced the RNA of 285,441 single cells from these organoids at seven developmental time points and from the periphery, fovea, pigment epithelium and choroid of light-responsive adult human retinas, and performed histochemistry. Cell types in organoids matured in vitro to a stable "developed" state at a rate similar to human retina development in vivo. Transcriptomes of organoid cell types converged toward the transcriptomes of adult peripheral retinal cell types. Expression of disease-associated genes was cell-type-specific in adult retina, and cell-type specificity was retained in organoids. We implicate unexpected cell types in diseases such as macular degeneration. This resource identifies cellular targets for studying disease mechanisms in organoids and for targeted repair in human retinas.

Corneal Endothelial Decompensation after Ocular Chemical Burn: Description of a New Finding.

BACKGROUND: Ocular chemical burn is an ophthalmological emergency. Therefore, chemical injuries should be promptly addressed in order to initiate the appropriate treatment as soon as possible and optimize the visual prognosis. We present a retrospective study of ten cases with ocular chemical burn including one with superglue and one with a liquid plaster material injury and describe their clinical course. HISTORY AND SIGNS: Ten adult patients (34 - 92 years, 8 males) presented with moderate to severe alkali or neutral chemical burns in our emergency clinics. They exhibited a variable degree of conjunctival injection, limbal ischemia, corneal erosion, and Descemet's folds. THERAPY AND OUTCOME: Patients were treated and complete corneal epithelial closure was achieved in all cases without significant signs of limbal stem cell insufficiency. Corneal endothelial insufficiency was observed in all cases. Nine patients had to be listed for corneal endothelial keratoplasty and one was treated with Descemet's stripping endothelial automated keratoplasty. CONCLUSIONS: Isolated corneal endothelial decompensation after chemical burns has not yet been described. The pathophysiological explanation of this observation remains, however, unknown. In view of this rare complication, it is important to follow patients after chemical ocular burn for possible development of endothelial decompensation.

Influence of Intraoperative Air Tamponade Time on Graft Adherence in Descemet Membrane Endothelial Keratoplasty.

PURPOSE: To study the influence of different intraoperative air tamponade times on graft adherence after Descemet membrane endothelial keratoplasty (DMEK). METHODS: In this interventional case series, we evaluated 117 eyes with Fuchs endothelial corneal dystrophy (FECD) that underwent DMEK using intraoperative air tamponade times of 60 minutes (group I; n = 39), 45 minutes (group II; n = 39), or 30 minutes (group III; n = 39). At 1 and 6 months postoperatively, graft adherence status, endothelial cell density, central pachymetry, and postoperative complications were recorded. RESULTS: At 1 month, 19 of the 117 eyes (16.2%) showed a clinically significant detachment (>1/3 of the graft surface area and affecting visual axis): 6 eyes in group I (15.4%), 5 eyes in group II (12.8%), and 8 eyes in group III (20.5%) (P = 0.82). A minor detachment (<1/3 of the graft surface area and not affecting visual axis) was observed in 6 eyes in group I (15.4%), in 7 eyes in group II (17.9%), and in 4 eyes in group III (10.3%) (P = 0.82). The overall rebubbling rate was 11%, with no difference among the groups (P = 0.07). Mean endothelial cell density decrease at 6 months was 41% (±17%) (P = 0.56), whereas mean central pachymetry decreased by 23 (±10) % (P = 0.77), with no differences between the groups. CONCLUSIONS: The incidence of graft detachment after DMEK for FECD did not differ between the eyes that had a 60-, 45-, or 30-minute intraoperative air tamponade. Reducing the intraoperative air tamponade time to 30 minutes may be considered for DMEK in eyes with uncomplicated FECD.

Tear Film Proteomics Reveal Important Differences Between Patients With and Without Ocular GvHD After Allogeneic Hematopoietic Cell Transplantation.

Purpose: To date, no biomarkers for ocular graft versus host disease (GvHD), a frequent complication following allogeneic hematopoietic cell transplantation (HCT), exist. In this prospective study, we evaluated the potential of human tear proteins as biomarkers for ocular GvHD. Methods: Tears from 10 patients with moderate-to-severe ocular GvHD were compared to 10 patients without ocular GvHD. After a full ocular surface clinical examination, tears were collected onto Schirmer strips and protein composition was analyzed by liquid chromatography tandem mass spectrometry. Statistical evaluation was performed using the Mann-Whitney U test to compare means and the false discovery rate method to adjust for multiple comparisons. Functional annotation of differentially expressed proteins was done with the PANTHER classification system. Results: We identified 282 proteins in tryptic digests of Schirmer strips; 79 proteins were significantly differentially expressed between the two groups, from which 54 were up- and 25 downregulated. The most upregulated proteins were classified as nucleic acid binding and cytoskeletal proteins, while the most extensively downregulated proteins belong to an array of classes including transfer and receptor proteins, enzyme modulators, and hydrolases. In addition to proteins already confirmed as differentially expressed in dry eye disease, we report changes in 36 novel proteins. Conclusions: This study reports the proteomic profile of tears in ocular GvHD for the first time and identifies a number of unique differentially expressed proteins. Further studies with a higher number of participants are necessary to confirm these results and to evaluate the reliability of these expression patterns in longitudinal studies.

Clinical Outcome of Rebubbling for Graft Detachment After Descemet Membrane Endothelial Keratoplasty.

PURPOSE: To assess the clinical outcome after successful rebubbling procedures for visually significant graft detachment after Descemet membrane endothelial keratoplasty (DMEK). METHODS: From a total of 760 consecutive DMEK surgeries, 41 eyes required rebubbling. Of those, 33 eyes of 31 patients were successful and were included in our retrospective outcome analysis study. Main outcome measures were compared with those of matched controls with uneventful primary DMEK (attached DMEK grafts without rebubbling). Rebubbling was performed on average 25 (±20) days (range 7-91 days) after DMEK. All eyes were evaluated for best-corrected visual acuity, endothelial cell density (ECD), pachymetry, and complications up to 6 months after rebubbling. RESULTS: At 6 months after DMEK, best-corrected visual acuity in rebubbled eyes did not differ from that in control eyes (P = 0.514). The mean ECD decrease was higher in rebubbled than in control eyes (54% vs. 35%, respectively, P = 0.001). Pachymetry did not differ between both groups (P = 0.153). After rebubbling, one buphthalmic eye showed temporary intraocular pressure elevation and 5 eyes had minor graft edge detachment that did not require further treatment. CONCLUSIONS: Rebubbling for DMEK graft detachment may result in similar visual outcomes as in uncomplicated DMEK, when performed within the first 6 to 8 postoperative weeks. However, rebubbled eyes may have lower ECD, which may be attributed to additional air bubble trauma and/or selection bias through more extensive manipulation during initial DMEK or higher risk of graft detachment in more complicated eyes.

Preliminary outcome of hemi-Descemet membrane endothelial keratoplasty for Fuchs endothelial dystrophy.

BACKGROUND/AIMS: To evaluate the clinical outcome of a full-diameter, untrephined, semicircular Descemet graft in a consecutive series of Descemet membrane endothelial keratoplasty (hemi-DMEK), potentially allowing the harvesting of two grafts from a single donor corneoscleral rim. METHODS: Interventional case series of 10 eyes of 10 patients with Fuchs endothelial dystrophy. Best corrected visual acuity (BCVA), endothelial cell density (ECD) and central corneal thickness (CCT) were evaluated up to 6 months postoperatively, and intraoperative and postoperative complications were recorded. RESULTS: Hemi-DMEK was successful in 9 out of 10 eyes; one eye showed persistent graft detachment despite rebubbling and underwent a secondary DMEK. BCVA improved in all successful hemi-DMEK eyes: at 6 months 100% of eyes (n=7) reached ≥20/40 (≥0.5), 86% (n=6) ≥20/25 (≥0.8), 29% (n=2) ≥20/20 (≥1.0) and 14% (n=1) reached 20/17 (≥1.2). Two eyes were excluded from visual analysis due to low visual potential. Preoperative donor ECD declined from 2744 (±181) cells/mm2 to 940 (±380) cells/mm2 centrally at 6 months postoperatively (n=9), with (donor and/or host) endothelial cell redistribution over bare stromal areas adjacent to the graft. Average CCT decreased from 745 (±153) µm preoperatively to 520 (±37) µm at 6 months. Four eyes required rebubbling for visually significant graft detachment. No other complications occurred throughout the study period. CONCLUSIONS: Hemi-DMEK may give visual outcomes similar to those in conventional DMEK. If ECD decrease and graft detachment rate would prove acceptable in larger series, hemi-DMEK could have the potential to double the availability of donor tissue for endothelial keratoplasty.

Rebubbling Techniques for Graft Detachment After Descemet Membrane Endothelial Keratoplasty.

PURPOSE: To describe rebubbling techniques in eyes with a visually significant graft detachment after Descemet membrane endothelial keratoplasty (DMEK). METHODS: Retrospective observational analysis at a tertiary referral center. A total of 41 eyes (39 patients) received rebubbling: 39 eyes (37 patients) had 1 and 2 eyes had 2 rebubbling procedures. Anterior segment optical coherence tomography and surgical videos were used to determine the best incisional approach for air injection, intraoperative maneuvers, and success rate (graft reattachment) at 1 week postoperatively. RESULTS: Rebubbling was performed on average 26 (±21) days (range: 7-92 days) after DMEK. Graft edge visibility and configuration of graft detachment were important parameters for the incisional approach for air injection: the air cannula was introduced in the area of graft attachment (attached area approach) (n = 25) or detachment (detached area approach) (n = 16). After excluding upside-down grafts (n = 3), the rebubbling success rate in total was 87% (33/38 eyes); in the attached area approach, it was 92% (22/24 eyes); and in the detached area approach, it was 79% (11/14). Of 14 eyes that had rebubbling later than 1 month postoperatively, 11 were successful; in 8 eyes, the graft seemed too stiff and/or immobile to allow complete unfolding. CONCLUSIONS: Rebubbling is a feasible procedure to manage graft detachment after DMEK if the graft is correctly oriented. Proper preoperative planning may aid in minimizing intraoperative complications and may increase the success rate. Late interventions (>1 month postoperatively) may still produce graft reattachment, but increased graft stiffness and/or fibrosis may complicate complete graft unfolding.