459 Pak J Ophthalmol. 2020, Vol. 36 (4): 459-460 

LETTER TO EDITOR 
 
 

Dear Sir 

I read the article published in your journal from 

authors Mahtab Mengal et al
1
 on the subject of 

trabeculectomy in congenital glaucoma. I have a keen 

interest in the subject they worked on and I appreciate 

authors’ hard work. The strength of the study was their 

very strict success criteria, which added a lot to my 

knowledge. However, there are few points I would like 

to get views from the authors’ for my better 

understanding. 

1. In material and methods, they stated the inclusion 
criteria and definition of congenital glaucoma as 

one entity. Did all or few or one of the features 

contributed to the diagnosis, because as much we 

know gender is never in definition of congenital 

glaucoma. Kindly comment. 

2. For sample size calculation why absolute precision 
of 0.10 was taken? Similarly, why anticipated 

population proportion of 92.3% was taken because 

the references they mentioned have no such 

figures. Moreover, reference no. 25 of their 

citation is not study about trabeculectomy so how 

they included it in the sample size calculation.
2 

How will they respond to this query? 

3. The authors have made some mistake in 
references, total references are 25 in their article 

but the attribution is of 27. How will they explain 

this? 

 I hope, you will get me these answers for updating 

my knowledge and better understanding. 

 
 

 

 

How to Cite this Article:  Mahsood YJ. Letter to 
Editor. Pak J Ophthalmol. 2020, 36 (4): 459-460. 

Doi: https://doi.org/10.36351/pjo.v36i4.1103 

 

 
 

Correspondence to: 

Yousaf Jamal Mahsood 

Assistant Professor Glaucoma 

Department of Ophthalmology 

Khyber Girls Medical College, Peshawar 

Email: yousaf82@hotmail.com 

 

 

REFERENCES 

1. Mengal M, Khan MA, Khan A, Ahmed M, 
Chaudhry RK, Khan NQ. Outcomes of 

Trabeculectomy in Congenital Glaucoma; 

Experience in Helpers Eye Hospital Quetta. Pak J 

Ophthalmol. 2020; 36 (3): 253-257. 

2. Tamcelik N, Özkiris A. Long-term results of 
viscotrabeculotomy in congenital glaucoma: 

comparison to classical trabeculotomy. Br J 

Ophthalmol. 2008; 92 (1): 36-39. 

 
REPLY 

We are glad to have received your response and 

appreciation, and I am thankful for the interest that 

you have shown in this topic. We will try to answer 

your questions, hopefully to your satisfaction, in the 

same order as you have put them before us. 

1. As for the first question, since our study was 
designed to recruit only patients with congenital 

glaucoma as participants, the operational 

definition of congenital glaucoma became the 

inclusion criteria as well. The reason for clearly 

stating that gender would not be a deciding factor 

within the inclusion criteria was to avoid any 

confusion among the research team during the 

recruitment process. 

2. Since cases of congenital glaucoma are not too 
frequent, and not all parents agree to have their 

children undergo trabeculectomy, therefore we 

decided that it would be adequate to have results 

that were precise within 10 percentage points 95% 

of the time. This was the reason for keeping the 

absolute precision value at 0.10 while the 

confidence interval remained 95%. The anticipated 

population proportion was chosen to be 92.3% 

based on available regional data, the referencing in 

the material and methods section however was 

failed to be updated along with the rest of the 

article and this has resulted in the wrong citation 

for the given value. The actual article for this 

number can be found in the reference number 14 

of the published article, which has been correctly 

cited for the figure of 92.3% in the introduction 

section of the published article. We are grateful to 

you for having raised this issue, and we will 

mailto:yousaf82@hotmail.com


Letter to Editor 

Pak J Ophthalmol. 2020, Vol. 36 (4): 459-460 460 

update the citation numbers for the material and 

methods section. 

3. For the last point, we would again like to express 
our gratitude at having brought up this point, and 

as mentioned, we will update the citation numbers 

for the material and methods section accordingly. 

 We hope that your queries have been 

answered to your satisfaction, and that all the 

points that were raised have been clarified 

adequately. The points you raised have been most 

pertinent and have helped us to rectify an 

oversight in our article. 

 

Mahtab Mengal 

Bolan University of Medical and Health Sciences 

(BUMHS), Quetta 

Email: mengalmahtab@yahoo.com 

 
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