Correlation between Placido-disc and rotating Scheimpflug keratometric findings before and after corneal crosslinking in children with keratoconus.

PURPOSE: To evaluate correlation between Placido-disc and rotating Scheimpflug keratometric findings in children with progressive keratoconus (KC) before and after corneal crosslinking (CXL) and investigate whether these limits of agreement varied according to disease severity. SETTING: Department of Ophthalmology of São Paulo Hospital, São Paulo, Brazil. DESIGN: Prospective nonrandomized open study. METHODS: Data obtained using rotating Scheimpflug-based tomography and Placido-disc-based topography devices were collected from preoperative and last follow-up postoperative children with KC operated on using standard CXL protocol. Correlation and agreement analyses were performed between the 2 devices before and after CXL to obtain keratometric (K) findings. RESULTS: 44 eyes from 44 patients aged 8 to 16 years were analyzed at all timepoints. All parameters were found to be strongly correlated before ( r = 0.84 to 0.99, P < .001) and after ( r = 0.93 to 0.99, P < .001) CXL. The mean Scheimpflug measurements of flat K, steep K, Kmax, mean K, and corneal astigmatism were higher than Placido-disc measurements in a preoperative period. This mean difference decreased in postoperative, but, with exception of Kmax and corneal astigmatism, Scheimpflug measurements remained higher. The mean parameter measurements from both devices decreased after CXL; 95% limits of agreement between instruments were wide for all parameters and decreased in postoperative and in mild KC. CONCLUSIONS: Keratometry measurements obtained using rotating Scheimpflug and Placido-disc technology were found to be closely correlated but not interchangeable before and after CXL in pediatric patients. Agreement between devices was better after CXL and in mild KC than in advanced KC.

Primary Pediatric Keratoplasty: Etiology, Graft Survival, and Visual Outcome.

PURPOSE: Interventional study to evaluate the etiology, visual outcome and survival of corneal transplantation in children and to identify the risk factors associated with graft failure. DESIGN: Retrospective, interventional consecutive case series. METHODS: Medical records of every child 7 years of age or younger who underwent primary penetrating keratoplasty at Department of Ophthalmology, Federal University of São Paulo were reviewed. The parameters evaluated were indications for keratoplasty, graft survival, and postoperative visual acuity (VA) improvement. Children underwent ophthalmologic examination before and after corneal graft, including VA, assessed by the preferential looking test and visual evoked potential. The analysis of transplant survival was performed using the Kaplan-Meier method. RESULTS: Fifty-six penetrating transplants were performed in 51 eyes of 43 children. The patients were divided into 2 groups: congenital (72.5%) and acquired (17.5%) corneal opacity. The main indication was congenital glaucoma (29.4%). The overall Kaplan-Meier graft survival rates were 64.7% in the postoperative average follow-up period of 24 months. There was no significant difference in graft survival between the congenital and acquired groups (Mantel-Cox P = .1031). There was significant improvement in VA in both groups (P = .0022 for congenital and P < .0001 for acquired). Rejection and diagnosis of congenital glaucoma were risk factors for graft failure. CONCLUSIONS: Congenital glaucoma was the main indication for corneal transplantation and despite the difficulties, prolonged survival and improved VA can be achieved in pediatric transplant. Complications such as rejection and early glaucoma were significantly associated with graft failure.