[Risk factors of cytomegalovirus infection in patients with failed corneal grafts]

Objective: To investigate the levels of cytomegalovirus (CMV) infection and associated risk factors in corneal transplant recipients who experienced transplant failure. Methods: This was a case-control study. Clinical data from 576 cases (576 eyes) of patients who underwent repeat corneal transplant surgery at the Department of Ophthalmology, Peking University Third Hospital, due to corneal transplant failure from January 2016 to May 2022 were collected. Of these, 305 were male and 271 were female, with a median age of 44.0 (0.7, 91.0) years. The CMV infection rate was analyzed based on the detection of CMV DNA in aqueous humor or corneal tissue during corneal transplant surgery. Patients were divided into the CMV group (CMV DNA positive) and the control group (herpes virus DNA negative). The main research indicators included the CMV infection rate, clinical characteristics, and risk factors in corneal transplant recipients. Chi-square tests and binary logistic analysis were used to compare differences between the two groups in general information, systemic diseases, ocular lesions, ocular surgical history, and local and systemic medications. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for each CMV infection risk factor. Results: The overall CMV infection rate was 21.9%(126/576), with annual rates ranging from 10.9% to 37.7% from 2016 to 2021. After applying inclusion and exclusion criteria, 378 patients were included in the control trial, with 126 in the CMV group and 252 in the control group. Statistically significant differences between the two groups were observed in systemic immune-related corneal lesions [CMV group: 38 (30.2%), control group: 26 (10.3%)], local immune and inflammatory corneal lesions [CMV group: 46 (36.5%), control group: 40 (15.9%)], congenital corneal opacity [CMV group: 46 (36.5%), control group: 48 (19.0%)] total number of corneal transplants (CMV group: 178 times, control group: 276 times), corneal deep neovascularization crossing the graft [CMV group: 104 (82.5%), control group: 68 (27.0%)] and severe opacity [CMV group: 44 (34.9%), control group: 30 (11.0%)]. Binary logistic regression analysis showed that systemic immune-related corneal lesions (OR=4.044, 95%CI 1.810-9.033, P<0.001), local immune and inflammatory corneal lesions (OR=3.554, 95%CI 1.569-8.052, P=0.002), congenital corneal opacity (OR=2.606, 95%CI 1.216-5.589, P=0.014), total number of corneal transplants (OR=3.206, 95%CI 1.753-5.864, P<0.001), corneal deep neovascularization crossing the graft (OR=8.347, 95%CI 3.967-17.559, P<0.001), and severe opacity (OR=3.063, 95%CI 1.221-7.682, P=0.017) were independent risk factors for CMV infection after corneal transplant. Conclusions: CMV infection was present in more than 1/5 of corneal transplant recipients who experienced transplant failure. CMV infection after corneal transplant may be related to immune rejection reactions and ocular inflammatory responses. Inflammatory corneal lesions associated with systemic or local immune abnormalities, congenital corneal opacity, and multiple corneal transplants may exacerbate the levels of inflammatory factors during the perioperative period of corneal transplant, increasing the risk of post-transplant CMV infection, leading to the infiltration of deep neovascularization and severe opacity in the cornea.

[Efficacy evaluation of 0.05% cyclosporine A and 0.1% tacrolimus eye drops in the treatment of severe dry eye associated with chronic graft-versus-host disease]

Objective: To evaluate the effectiveness and safety of 0.05% cyclosporine A and 0.1% tacrolimus eye drops in treating severe dry eye associated with chronic graft-versus-host disease (cGVHD). Methods: This non-randomized concurrent control trial enrolled 83 eyes from 83 patients with cGVHD-associated severe dry eye. The treatment had two phases. During the initial shock treatment period (0-3 months), 44 patients received 0.05% cyclosporine A eye drops (4 times/day; group A) and 39 patients received 0.1% tacrolimus eye drops (twice/day; group B) alongside basic treatment. In the maintenance treatment period (3-6 months), both groups used 0.05% cyclosporine A eye drops (twice/day) and sodium hyaluronate. Examinations were conducted at 1, 3, and 6 months after treatment initiation, assessing the Ocular Surface Disease Index (OSDI), corneal fluorescein staining (CFS) score, and fluorescein tear break-up time (BUT) for efficacy. visual acuity and intraocular pressure (IOP) were evaluated for safety, and patients' post-medication irritation symptoms were recorded. Results: The study included 52 males and 31 females, aged (28.57±15.67) years. After 1 month of treatment, the CFS score in group A significantly decreased from 10.0 (6.0, 14.0) to 5.0 (3.0, 8.5) (P<0.001). in group B, the CFS score also significantly decreased from 10.0 (6.0, 15.0) to 6.0 (2.0, 10.0), and the BUT increased from 2.0 (1.0, 2.0) s to 2.0 (1.8, 3.3) s (P<0.001). No significant OSDI decrease was observed in either group. No significant differences were found in OSDI, CFS score, and BUT between the two groups. After 3 months, group A showed significant improvement in OSDI, CFS score, and BUT (P<0.05), while group B only demonstrated significant CFS score decrease (P<0.05). OSDI was significantly lower in group A than group B (P<0.05). No significant differences were noted in CFS score and BUT between groups. After 6 months, OSDI, CFS score, and BUT were 18.9 (9.3, 34.2), 7.0 (3.0, 8.5), and 2.0 (1.0, 3.0) s in group A, and 10.9 (3.6, 35.4), 5.5 (2.8, 10.0), and 2.0 (1.0, 10.0) s in group B. In both groups, CFS scores significantly decreased and BUT increased (P<0.05). Visual acuity improved significantly in group A at 1, 3, and 6 months (P<0.05), while no significant changes were seen in group B. Irritation symptoms were transient and self-resolving in both groups. Conclusions: Both 0.05% cyclosporine A and 0.1% tacrolimus eye drops, when combined with local glucocorticoids, exhibited significant anti-inflammatory effects, effectively and safely treating severe dry eye in cGVHD patients. Although the onset of 0.05% cyclosporine A was slower than 0.1% tacrolimus, it offered more stable long-term effects and better symptom improvement.

[Imaging features of posterior polymorphous corneal dystrophy observed by in vivo confocal microscopy]

Objective: To identify and analyze imaging features of posterior polymorphous corneal dystrophy (PPCD) by in vivo confocal microscopy (IVCM). Methods: This retrospective case series enrolled 27 eyes of 18 patients (including 10 males and 8 females) who were diagnosed with PPCD at the Department of Ophthalmology in Peking University Third Hospital between January 2013 and December 2019. The mean age was (23.61±14.81) years. There were 9 monocular and 9 binocular cases. All patients were examined by slit-lamp biomicroscopy and IVCM. The visual acuity, the mean endothelial cell density, and the images of IVCM were analyzed in all cases. Results: The mean best-corrected visual acuity was 0.76±0.33, and the mean endothelial cell density was (1 723.6±698.3) cells/mm². The IVCM images of type 1 PPCD (vesicular lesions) showed hyperreflective, placoid or homocentric lesions at the level of the Descemet's membrane, hyporeflective, oval or round lesions at the level of the Descemet's membrane, and hyporeflective, crater-like lesions at the level of the endothelial cell layer. The IVCM images of type 2 PPCD (band lesions) displayed hyperreflective, band lesions and a fibrous strand structure at the level of the Descemet's membrane, hyporeflective, vesicular lesions at the level of the Descemet's membrane, and hyporeflective, trough-and ridge-like lesions at the level of the endothelial cell layer. The IVCM images of type 3 PPCD (geographic placoid opacities) showed loss of the hexagonal features of endothelial cells and epithelial-like cell transformation. Conclusions: PPCD primarily affects the endothelium and Descemet's membrane. IVCM could highlight the special characteristics of PPCD including hyperreflective lesions at the level of the Descemet's membrane, hyporeflective lesions at the level of the endothelial cell layer, and epithelial-like cell transformation of endothelial cells. IVCM is an invaluable tool for clinical diagnosis and dynamic monitoring of PPCD.

[Descemet's stripping endothelial keratoplasty (DSAEK) in failed penetrating keratoplasty patients: graft survival rate and its associated factors]

Objective: To explore graft survival rate and its associated factors of DSAEK in patients with endothelial decompensation after penetrating keratoplasty (PKP). Methods: A retrospective case study was conducted, including 51 patients (51 eyes) that underwent DSAEK for endothelial decompensation after PKP in Department of Ophthalmology in Peking University Third Hospital from June 2009 to September 2017. The mean recipient age was (43.3±21.0) years. There were 36 males and 15 females. Data comprising demographic details,surgical methods, complications,follow-up durations,final states of grafts,preoperative and postoperative risk factors were collected. Kaplan-Meier analysis was used to determine the cumulative probability of graft survival. Cox regression model was developed to examine for factors associated with graft survival. Results: Among 51 eyes,the overall graft survival rate was 78%(40/51). The cumulative probability was 85% (95%CI: 0.73-0.96) and 69% (95%CI: 0.52-0.86) at 1 year and 2 years, respectively. The median survival time was 42 months. The diameter of DSAEK graft and postoperative intraocular pressure correlated with the long-term survival of graft. Larger diameter of DSAEK graft was a protective factor for graft survival (HR=0.29, 95%CI: 0.12-0.73), while postoperative high intraocular pressure was a risk factor (HR=1.08, 95%CI: 1.00-1.16, HR=1.10, 95%CI:1.01-1.12). Recipient age, sex, lens status, the number of previous PKPs and previous glaucoma surgery had no significant effect on long-term survival (P>0.05). Conclusions: DSAEK is an effective treatment for endothelial decompensation after PKP,with favorable graft survival rate. Larger diameter of graft is beneficial to the long-term survival,while high postoperative intraocular pressure is a risk factor for graft failure. (Chin J Ophthalmol, 2019, 55: 428-434).

Ultralow-power complementary metal-oxide-semiconductor inverters constructed on Schottky barrier modified nanowire metal-oxide-semiconductor field-effect-transistors

We show that the threshold voltages of both n- and p-channel metal-oxide-semiconductor field-effect-transistors (MOSFETs) can be lowered to close to zero by adding extra Schottky contacts on top of nanowires (NWs). Novel complementary metal-oxide-semiconductor (CMOS) inverters are constructed on these Schottky barrier modified n- and p-channel NW MOSFETs. Based on the high performances of the modified n- and p-channel MOSFETs, especially the low threshold voltages, the as-fabricated CMOS inverters have low operating voltage, high voltage gain, and ultra-low static power dissipation.