Dear Editor,
This is regarding the comments on “Efficacy of dorzolamide in improving ocular blood flow in patients with open-angle glaucoma: The Indian carbonic anhydrase inhibitor trial.” Thank you for your comments[1] and interest in reading our article.[2]
The study was a single-blinded one where in the glaucoma consultant knew about the patient but the radiologist who performed Doppler was not aware of the diagnosis and the treatment history of the patient.[3] Moreover, the radiologist was in another center so he was not having access to the case records and we did take Doppler imaging for healthy volunteers too during the study period.
Yes, it is a good suggestion. Literature has enough evidence to prove that dorzolamide eye drops increase the ocular blood flow when compared with timolol[4] and latanoprost.[5] But in our study, we had studied the efficacy of only dorzolamide as it was a pilot study to see the effect in Indian eyes as there was no publication regarding this aspect from our country at the time of initiation of this study.
Color Doppler imaging (CDI) measurements were taken using GE healthcare produces these Ultrasound machines with a 7.5 MHz linear probe in the same center with a single qualified examiner.
The values are highly interpreter-dependent so it would be better to do any follow-up with the same examiner. The values do change with the pressure exerted during an examination, so we made sure that all scans were done by an experienced radiologist.
We understand the importance of retinal nerve fiber analysis and follow-up in our study but we were not able to get those data due to logistic issues.
We once again appreciate your input. As researchers and constant learners, it is encouraging to know that our article has reached many ophthalmologists.
Financial support and sponsorship
Research Grant from Cipla.
Conflicts of interest
There are no conflicts of interest.
References
- 1.Srikanth K, Khurana DA. Comments on:Efficacy of dorzolamide in improving ocular blood flow in patients with open-angle glaucoma:The Indian carbonic anhydrase inhibitor trial. Indian J Ophthalmol. 2023;71:2312–3. doi: 10.4103/IJO.IJO_3282_22. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Nivean PD, Ariga M, Chithra MR, Gohil P, Das S, Jaideep G. Efficacy of dorzolamide in improving ocular blood flow in patients with open-angle glaucoma:The Indian carbonic anhydrase inhibitor trial. Indian J Ophthalmol. 2022;70:4164–7. doi: 10.4103/ijo.IJO_1055_22. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.David S, Khandhar PB. StatPearls. Treasure Island (FL): StatPearls Publishing; 2022. [Updated 2022 Jul 18]. Double-Blind Study. Available from:https://www.ncbi.nlm.nih.gov/books/NBK546641/ [Google Scholar]
- 4.Fuchsjäger-Mayrl G, Wally B, Rainer G, Buehl W, Aggermann T, Kolodjaschna J, et al. Effect of dorzolamide and timolol on ocular blood flow in patients with primary open angle glaucoma and ocular hypertension. Br J Ophthalmol. 2005;89:1293–7. doi: 10.1136/bjo.2005.067637. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Zeitz O, Matthiessen ET, Reuss J, Wiermann A, Wagenfeld L, Galambos P, et al. Effects of glaucoma drugs on ocular hemodynamics in normal tension glaucoma:A randomized trial comparing bimatoprost and latanoprost with dorzolamide [ISRCTN18873428. BMC Ophthalmol. 2005;5:6. doi: 10.1186/1471-2415-5-6. [DOI] [PMC free article] [PubMed] [Google Scholar]