Skip to main content

Archived Comments for: Spectral-domain optical coherence tomography evaluation of postoperative cystoid macular oedema following phacoemulsification with intraoperative complication

Back to article

  1. Is the macular thickness a risk factor for development of phacoemulsification-associated cystoid macular oedema?

    Alejandro Allocco, Instituto Santa Lucia Parana

    20 March 2014

    Dear Sir,

                We read with interest the article by Khaw et al [1]. Authors assessed collateral damage associated with phacoemulsification in patients with intraoperative complication, such as post-operative Cystoid Macular Oedema (CMO), by using spectral-domain optical coherence tomography (OCT). In a prospective, observational, study, they observed development of CMO by serial OCT in 34% of 47 eligible eyes, as well as the expectable relationship with the macular thickness increase and best-corrected visual acuity decrease over time. To our opinion, albeit this cohort shed further light on the importance of serial OCT for early detection of CMO, it overlooks a crucial issue: the role of baseline macular thickness as a risk factor for CMO development. Indeed, authors found that the mean macular thickness at baseline was 273 ± 24 μm and 259 ± 21 μm among patients belonging to the CMO and non-CMO groups, respectively. Because of the p value was 0.06 (i.e. very close to the arbitrarily adopted significant level of 0.05), authors considered that this difference lacked statistical significance. However, we believe that such an assumption comes from a technical weakness of the study design, that is, the insufficient number of subjects. This issue would have been solved if authors would have estimated previously the minimal size of sample required to demonstrated statistically significant difference between groups. As an alternative, a bivariate analysis comparing the proportion of patients displaying   macular thickness at baseline ≥ 270 μm (as a tentative “risk cut-off”) among patients belonging to the CMO and non-CMO groups, with the corresponding odds ratio and p values would have been useful to address this question. In fact, the notion that a higher basal macular thickness renders patients more susceptible to develop enhanced inflammatory reaction seems attractive. 

    Therefore, we consider that knowing this potential predisposing factor prior to the surgery should be crucial to prevent or limit CMO associated with phacoemulsification in patients with intraoperative complication by administration of perioperative non-steroidal anti-inflammatory drugs (NSAID) to patients at risk. We have recently reviewed the role of steroids and NSAID in preventing the occurrence of CMO, after uneventful phacoemulsification [2]. Although their actual benefit remains to be fully elucidated, the dosing strategy we propose in this review might be useful to approach the above discussed target patients. Further studies are certainly required to definitively determine the most cost-effective management of this worrisome collateral damage in subjects with intraoperative complication undergoing phacoemulsification.     

    References:

    1. Keat Ween Khaw, Hee Hong Lam, Tsung Fei Khang, Azida Juana Wan Ab Kadir, Visvaraja Subrayan: Spectral-domain optical coherence tomography evaluation of postoperative cystoid macular oedema following phacoemulsification with intraoperative complication. BMC Ophthalmology 2014, 14:16.
    2. Alejandro R Allocco, Nicolás E Quintana, Julia A Ponce, Mauricio GB Magurno: Non Steroidal Anti Inflammatory Drugs in the Prevention of Cystoid Macular Edema after Uneventful Cataract Surgery. Clinical Ophthalmology, in press.

    Competing interests

    The authors declare no conflict of interest.

Advertisement