Comments on “A Prospective Observational Study on Changes in Intraocular Pressure and Iridocorneal Angle Following the Use of Escitalopram and Amitriptyline”

We read with interest the article by Mandal et al. ¹ It is a pertinent study on the effect of escitalopram and amitriptyline on intraocular pressure (IOP) and iridocorneal angle.

Escitalopram and amitriptyline are commonly used antidepressants. ² The authors choosing two drugs belonging to different classes of antidepressants was relevant as it would help choose a drug for patients predisposed to angle closure.

However, we feel the study methodology could have been more rigorous. Firstly, it needs to be considered that IOP is a dynamic variable. Various factors, including the time of the day or the position of the patient, are known to alter IOP. ³ An average (mean) of multiple readings of IOP is an accepted practice.^4,5 Secondly, slit lamp gonioscopy, although useful in the clinical setting, is less useful in a research setting due to poor reproducibility. ⁶ Wide inter-observer variations exist between general ophthalmologists and glaucoma specialists in assessing gonioscopic findings. ⁷ Further, gonioscopy assessment is affected by testing conditions, such as ambient illumination. ⁸ Hence, reporting the average of multiple IOP readings, employing uniform testing conditions, and ensuring agreement between observers would have been useful.

Pupillary dilatation resulting from the anticholinergic action or increased serotonin levels has been proposed as a possible mechanism for the raised IOP caused by selective serotonin reuptake inhibitors. ⁹ Further, the authors could have employed imaging techniques, such as anterior segment optical coherence tomography and ultrasound biomicro- scopy, to assess the changes in the iridocorneal angle.^10,11 Hence, both monitoring the pupillary dilatation and imaging techniques could have helped in understanding the mechanism underlying the variations in the IOP following the psychotropic intake.

Psychological stress can elevate IOP even in healthy individuals. ¹² Besides, anxiety and depression can increase the risk of progression of glaucoma. ¹³ Hence, it would have been worthwhile to rate the severity of anxiety and depression symptoms in the patients, to see if that was a confounding factor to account for the differences in IOP.

The risk of an acute IOP spike would depend on the configuration of the angle at baseline. In an Asian study, a narrower angle width, observed through gonioscopy, was the only clinical parameter identified for a significant increase in the IOP after pupil dilation. ¹⁴ It is unlikely that an eye with a wide open angle would go into acute angle closure. Hence, reporting the IOP and angle changes at the baseline would help ascertain whether angles that were narrower at the baseline showed more significant variations.

Overall, this study is a significant contribution. However, consideration of the points we raised would have further strengthened it.