Vincenzo Scorcia1, Giuseppe Giannaccare2, Andrea Lucisano2, Mauro Soda2, Giovanna Carnovale Scalzo2, James Myerscough3, Marco Pellegrini4, Francesco Verdoliva2, Gabriele Piccoli2, Cristina Bovone5, Massimo Busin5. 1. Department of Ophthalmology, University Magna Græcia, Catanzaro, Italy; Istituto Internazionale per la Ricerca in Oftalmologia (IRFO), Forlì, Italy. Electronic address: vscorcia@libero.it. 2. Department of Ophthalmology, University Magna Græcia, Catanzaro, Italy. 3. Ospedale Privato Villa Igea, Forlì, Italy. 4. Ophthalmology Unit, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy. 5. Istituto Internazionale per la Ricerca in Oftalmologia (IRFO), Forlì, Italy; Ospedale Privato Villa Igea, Forlì, Italy; Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy.
Abstract
PURPOSE: To identify predictors of bubble formation and type during big-bubble deep anterior lamellar keratoplasty (BB-DALK) performed in keratoconus at different stages of severity. DESIGN: Retrospective Cohort Study. METHODS: Setting: University Magna Græcia (Catanzaro, Italy); Study Population: Consecutive keratoconus patients undergoing BB-DALK from September 2014 to February 2019. OBSERVATION PROCEDURE: Keratometric astigmatism, mean keratometry value (K-mean), highest keratometry value (K-max), thinnest point, anterior segment optical coherence tomography (AS-OCT)-based stage of ectasia. MAIN OUTCOME MEASURES: Rate of bubble formation and type; number and fate of micro-/macroperforation; conversion to mushroom keratoplasty (MK); comparison of parameters in patients with bubble formation vs failure and in type 1 vs type 2 bubble; areas under the curves (AUC) of preoperative parameters for distinguishing between bubble types. RESULTS: Pneumatic dissection succeeded in 113 of 155 eyes (72.9%), with 100 type 1 bubbles (88.4%), 11 type 2 (9.8%), and 2 mixed-type (1.8%). Microperforations were managed conservatively in type 1 bubbles; macroperforations occurring in both types of bubbles required conversion to MK. Preoperative K-mean and K-max values were significantly higher in eyes in which bubble formation succeeded (respectively, P = .006 and P < .013). Type 1 bubbles formed in eyes with significantly lower age, K-mean, and AS-OCT stages and higher pachymetric values (always P < .029). Age had the highest diagnostic power for discrimination between bubble types, followed by AS-OCT stage, pachymetry, K-mean, and astigmatism (respectively, AUC = 0.861, 0.779, 0.748, 0.700, 0.670). CONCLUSIONS: Older age and advanced stages of keratoconus were predictors of type 2 bubble formation during BB-DALK that was associated with an increased risk of complications.
PURPOSE: To identify predictors of bubble formation and type during big-bubble deep anterior lamellar keratoplasty (BB-DALK) performed in keratoconus at different stages of severity. DESIGN: Retrospective Cohort Study. METHODS: Setting: University Magna Græcia (Catanzaro, Italy); Study Population: Consecutive keratoconus patients undergoing BB-DALK from September 2014 to February 2019. OBSERVATION PROCEDURE: Keratometric astigmatism, mean keratometry value (K-mean), highest keratometry value (K-max), thinnest point, anterior segment optical coherence tomography (AS-OCT)-based stage of ectasia. MAIN OUTCOME MEASURES: Rate of bubble formation and type; number and fate of micro-/macroperforation; conversion to mushroom keratoplasty (MK); comparison of parameters in patients with bubble formation vs failure and in type 1 vs type 2 bubble; areas under the curves (AUC) of preoperative parameters for distinguishing between bubble types. RESULTS: Pneumatic dissection succeeded in 113 of 155 eyes (72.9%), with 100 type 1 bubbles (88.4%), 11 type 2 (9.8%), and 2 mixed-type (1.8%). Microperforations were managed conservatively in type 1 bubbles; macroperforations occurring in both types of bubbles required conversion to MK. Preoperative K-mean and K-max values were significantly higher in eyes in which bubble formation succeeded (respectively, P = .006 and P < .013). Type 1 bubbles formed in eyes with significantly lower age, K-mean, and AS-OCT stages and higher pachymetric values (always P < .029). Age had the highest diagnostic power for discrimination between bubble types, followed by AS-OCT stage, pachymetry, K-mean, and astigmatism (respectively, AUC = 0.861, 0.779, 0.748, 0.700, 0.670). CONCLUSIONS: Older age and advanced stages of keratoconus were predictors of type 2 bubble formation during BB-DALK that was associated with an increased risk of complications.