Cumulative dissipated energy in eyes with and without corneal opacity.

Objective: To compare ultrasonic energy delivered into the eye [cumulative dissipated energy, (CDE)] and frequencies of required auxiliary surgical methods during phacoemulsification surgery in eyes with and without corneal opacity. Methods: The study was designed as a retrospective comparative observational study. The study group [Corneal Opacity Group, (COG)] was comprised of 31 eyes of 31 cataract patients with corneal opacity. Only nebular and macular corneal opacities (according to slit-lamp based classification of Agrawal) were included in the study. The control group (CG) was comprised of 40 eyes of 40 cataract patients without corneal opacity. The CDE values were obtained using the Centurion system (Alcon, Fort Worth, TX) and the patients were followed-up postoperatively for a period of one month. Results: The mean age of the subjects was 71.46 ± 8.86 years (52-89) in COG and 66.12 ± 5.96 years (55-80) in CG (p >0.05). In COG, the most common etiologic factors were trauma, keratitis, and degenerative diseases. The mean CDE value was 15.16 ± 8.71 (2.20-42.65) in COG and 10.04 ± 6.28 (3.77-31.80) in CG and it was found as significantly higher in COG (p=0.003). Some auxiliary surgical methods including posterior synechiolysis and anterior capsule staining were more commonly performed in COG (p=0.044 and p=0.040, respectively). No intraoperative or postoperative complication was observed. Conclusion: More ultrasonic energy is delivered into the eye and more auxiliary surgical methods are needed in cataract patients with corneal opacity who underwent phacoemulsification. Abbreviations: CDE = Cumulative dissipated energy, COG = Corneal Opacity Group, CG = Control group, IOL = Intraocular lens, LOCS = Lens Opacities Classification System, BCVA = best-corrected visual acuity, SRK/T = Sanders, Retzlaff, and Kraff theoretical, OVD = ophthalmic viscosurgical device, SPSS = Statistical Package for the Social Sciences.