In this retrospective, interventional consecutive case series, we included 11 eyes from 7 patients who were clinically diagnosed with irreversible corneal decompensation secondary to ARS and treated with keratoplasty at the Ophthalmology Department of Peking University Third Hospital from January 2014 to January 2021. The study was conducted in compliance with the principles of the Declaration of Helsinki and approved by the Human Research Ethics Committee of Peking University Third Hospital. Informed consent to use images and data in this study was obtained from each participant or their guardian.
Patients were diagnosed according to the following inclusion criteria [3–5]: (1) bilateral congenital anterior segment dysgenesis, including iris abnormalities, such as iris stromal hypoplasia, corectopia, polycoria, ectropion uveae, iridocorneal adhesion or posterior embryotoxon; (2) corneal edema and/or opacity; with or without (3) systemic abnormalities, including midface dysmorphism, dental abnormalities, redundant periumbilical skin or other systemic defects.
Preoperative case records were reviewed for the following data: demographics (age at time of keratoplasty, and sex), ocular histories (medical and surgical interventions), best-corrected visual acuity (BCVA) (LogMAR visual chart), IOP (Goldmann tonometer), slit-lamp findings, central corneal thickness (CCT) and anterior chamber depth (ACD) (anterior segment optical coherence tomography) (AS-OCT, Visante, Carl Zeiss Meditec, Dublin, CA, USA), morphological changes and endothelial cell density (ECD) in central endothelial cells (in vivo confocal microscopy) (ICVM, Heideberg Retina Tomograph 3 with Rostock Cornea Module; Heideberg Engineering, GmBH, Dossenheim, Germany), and ECD of the donor tissue (Specular microscope Group I, Class A) (HAI EB-3000 xyz, HAI laboratories, Inc., USA). For LogMAR values worse than 1.6, the following previously described scale was used: counting fingers, 2.0; hand motion, 2.3; light perception, 2.6; and no light perception, 2.9 .
All keratoplasty operations were performed by a single surgeon (JH). In addition to their own or their guardians’ wishes, patients with severe edematous corneas or extremely shallow anterior chambers underwent PK, while the others underwent DSAEK. Referring to the standard procedures, PK (4 grafts, 3 patients) and DSAEK (8 grafts, 5 patients) were performed to replace the full-thickness edematous cornea and the diseased corneal endothelium, respectively [14, 15].
Synechiolysis and special considerations for PK. After full-thickness corneal trephination, the iris adhered to the excised cornea was cut with microscissors. Iridocorneal adhesion was carefully broken with viscoelastic (Abbott Medical Optics, Abbott Park, Illinois, USA) or microscissors. Then, the donor tissue was transferred to the host and sutured with 10-0 Prolene sutures. To reduce the risk of peripheral anterior synechiae (PAS) and secondary glaucoma postoperatively, a 0.75 to 1.00 mm oversized donor cornea was sutured, which depended on each patient’s specific requirements.
Synechiolysis and special considerations for DSAEK. An epithelial trephine mark with a diameter of 7.5 or 8.0 mm was made. Viscoelastic from the paracentesis incision was required to break iridocorneal adhesion and maintain the anterior chamber. However, the iris that adhered to the cornea tightly was broken with the mental stab knife. A reverse Terry-Sinskey hook (Bausch and Lomb Surgical, St. Louis, MO, USA) was used to score the endothelium/DM. Then, a Terry Scraper (Bausch and Lomb Surgical) was used to smooth out the rough recipient bed, especially the periphery. Gentle pressure was applied to the inner cornea, taking care not to tear or disrupt corneal stromal fibers. To avoid postoperative PAS and angle obstruction, the 1.5 mm rim of endothelium/DM within the limbus was left behind. The donor tissue was prepared by a Moria automated lamellar therapeutic keratoplasty microkeratome and associated artificial anterior chamber (Moria Inc. Doylestown, PA, USA). A donor lenticule ranging from 120 to 150 µm in thickness was recommended. Removing viscoelastic, the donor lenticule was inserted into the anterior chamber with the suture pull-through insertion technique [14, 15] and unfolded in balanced salt solution (BSS, Alcon, Fort Worth, TX, USA). A lenticule-sized bubble was injected from the paracentesis incision, and the donor lenticule was positioned and centered with a roller. The air bubble was maintained for 10 minutes and then reduced to 75% volume in the anterior chamber. The patient remained supine for 4 hours as required after DSAEK.
Topical eye drops, including prednisolone acetate (1.0%, Allergan, Inc., Irvine, CA, USA), levofloxacin (0.5%, Santen Co., Ishikawa, Japan) (patients aged 12 years or older) or tobramycin (0.3%, Alcon Laboratories, Inc., Fort Worth, TX) (patients younger than 12 years), and artificial tears were administered 4 times daily for the first week, with a gradual decrease as clinically indicated in the following 12 months. Then, a maintenance regimen of low-dose steroids was used from 12 months to 18-24 months after keratoplasty. Tobramycin and dexamethasone eye ointment (tobramycin 0.3% and dexamethasone 0.1%, Alcon Laboratories, Inc., Fort Worth, TX) was required every night for the first week after PK. Cyclosporin (1%, North China Pharmaceutical Company, Ltd., Shijiazhuang, Hebei Province, China) (DSAEK) or tacrolimus (0.1%, Senju Pharmaceutical Co. Ltd., Japan) (PK) was applied 4 times daily from 1 week after keratoplasty, with a gradual decrease as clinically indicated in the following 18 to 24 months. All children were referred to a pediatric ophthalmologist for amblyopia treatment 1 month after keratoplasty.
Patients were routinely evaluated at 1, 3, 7 and 30 days, 3 months, 6 months, and 12 months after keratoplasty and twice per year thereafter. More frequent reviews were performed as necessary. BCVA, IOP, corneal clarity and complications were recorded at each follow-up. ICVM for determining central ECD was performed at 1, 6, and 12 months and once per year thereafter. Graft rejection, primary graft failure and secondary graft failure were described in detail previously [16, 17]. The values were excluded from the following analysis in the presence of irreversible corneal decompensation and repeat keratoplasty.
The endothelial cell loss (ECL) rate was calculated by subtracting postoperative ECD from baseline donor ECD and then dividing by baseline donor ECD and multiplying by 100. The distribution of the data was assessed for normality via the Kolmogorov-Smirnoff-Lillefors test. Data are presented as the mean ± standard deviation. The data with a normal distribution were estimated using a t-test. Analysis for data with nonnormal distributions was performed using the Wilcoxon Mann-Whitney or Wilcoxon signed rank test as appropriate. Categorical variables were compared using Chi-square/Fisher’s exact test. The potential association between the 6-month ECL rate and the 12-month ECL rate and previous glaucoma surgeries, baseline IOP, ACD before keratoplasty, type of keratoplasty, and additional glaucoma surgeries after keratoplasty was assessed by analysis of variance. A two-sided P value < 0.05 was considered statistically significant. Statistical analysis was performed using IBM SPSS statistics, version 24.0 (SPSS, Inc., Chicago, IL, USA).