F1000Research F1000Research 2046-1402 F1000 Research Limited London, UK 10.12688/f1000research.140576.1 Study Protocol Articles A comparative study of central macular thickness and endothelial cell changes in patients with diabetes mellitus undergoing phacoemulsification.

[version 1; peer review: awaiting peer review]

 Kulkarni Aditi Conceptualization Investigation Methodology https://orcid.org/0009-0009-8380-4592 a 1 Thool Archana Supervision Validation Writing – Review & Editing 1 Ophthalmology, JNMC Datta meghe institute of higher education and research, Wardha, Maharashtra, 442001, India ask26031996@gmail.com

No competing interests were disclosed.

 8 11 2023 2023 12 1446 13 10 2023 Copyright: © 2023 Kulkarni A and Thool A 2023 This is an open access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

One of the most prevalent causes of blindness worldwide is cataracts. Along with the lens, Diabetes mellitus can impact all ocular structures. Diabetics have a higher incidence of cataract formation due to a variety of reasons. Diabetic people may have thicker corneas. The most frequent reason for poor vision recovery after surgery is macular edema, which is caused by cataract surgery. Therefore, after phacoemulsification, we are measuring the central macular thickness and central corneal thickness in diabetics in order to observe the post phacoemulsification macular edema and any significant changes in corneal thickness. We expect a morphological changes in endothelial cells, increase central corneal thickness and increase central macular thickness post-operatively after uncomplicated phacoemulsification surgery.

 Diabetic retinopathy macular thickness uncomplicated phacoemulsification surgery The author(s) declared that no grants were involved in supporting this work. Introduction

One of the most prevalent causes of blindness worldwide is cataracts. According to the WHO, cataracts account for 47.8% of blindness worldwide, leaving 17.7 million people without sight. 1 Cataracts are to blame for 80% of the blindness in India. 2

The prevalence of diabetes mellitus (DM), a chronic systemic illness, has risen over time. Along with the lens, DM can impact all ocular structures. Diabetics have a higher incidence of cataract formation due to a variety of reasons such as age and glycaemic control were consistently associated with cataract development. Nowadays, cataract surgery is a routine and a safe process because of technology. However, diabetics are still at risk for problems that might impair vision, including posterior capsular opacification, diabetic retinopathy development, diabetic macular edoema (ME), postoperative ME, and diabetic retinopathy. 3

Maintaining corneal clarity depends heavily on the corneal endothelium. Since corneal endothelial cells are mitotic in vivo, maintaining the health of this cell layer is crucial as the cell density declines with ageing and disease. The corneal endothelium may experience structural and functional problems as a result of diabetes, which will reduce the cellular reserve available to respond to stress. Long-term illness and situations where there is inadequate metabolic control have both been shown to cause significant endothelial cell loss. It was of worry that the medical management of diabetes or the retinal complications would cause endothelial cell loss and damage. Additionally, diabetic patients may experience an increase in corneal thickness. In research comparing diabetic and non-diabetic patients having cataract surgery, the decrease in ECD is larger in diabetic patients in every instance. 4

To keep an eye on corneal edoema, one measures central corneal thickness (CCT). Patients with diabetes typically experience increased corneal thickness. 5 The severity of diabetic retinopathy and corneal thickness are related. After cataract surgery, the corneal endothelial cells’ morphological stability and functional integrity are crucial for maintaining long-term corneal transparency. After cataract surgery, endothelial cell loss and corneal decompensation have been well-documented. 6 The intraoperative manipulation of the cornea during surgical procedures that include entry into the anterior chamber results in some endothelial cells being damaged. Endothelial cell density and morphology vary as a result of neighboring cells enlarging and sliding across to maintain endothelial cell continuity after endothelial cell loss. A little endothelial injury following surgery might also result in a transient increase in corneal thickness. 7 Endothelial cell density and central corneal thickness can be assessed clinically using specular microscopy. 8

The most frequent reason for poor vision recovery after surgery is macular edoema, which is caused by cataract surgery. 9 – 11 OCT is helpful for measuring both quantitative and qualitative macula characteristics. Though the precise mechanism is unknown, studies have demonstrated a greater prevalence of post-operative macular edoema in eyes with diabetic retinopathy and pre-existing macular edoema. 12 – 14

This study is important to observe the morphological changes in endothelial cells, increase central corneal thickness and increase central macular thickness post-operatively after uncomplicated phacoemulsification surgery. This will be useful in assessing the significant corneal and macular changes in patients with diabetic following phacoemulsification.

Aims and objectives

Aim – To compare the morphological and functional endothelial changes and central macular thickness, preoperatively and postoperatively, in patients with diabetes mellitus undergoing phacoemulsification.

Objectives – To compare the central corneal thickness in diabetic patients undergoing phacoemulsification, preoperatively and postoperatively, by specular microscopy. To compare the endothelial cell density in diabetic patients undergoing phacoemulsification, preoperatively and postoperatively, by specular microscopy. To study the coefficient of variation and resultant hexagonality of corneal endothelial cells in diabetic patients undergoing phacoemulsification, preoperatively and postoperatively, by specular microscopy. To compare the central macular thickness in patients with diabetes mellitus undergoing phacoemulsification, preoperatively and postoperatively, by optical coherence tomography.

Trial Design – Prospective, interventional study.

 Protocol

Inclusion criteria – Patients included with grade 2–4 cataract according to LOCS III coming to ophthalmology OPD AVBRH with type 2 diabetes mellitus upto 10 years with diabetic retinopathy and macular edema present or absent who is willing to provide written informed consent.

Exclusion criteria – Patients having traumatic cataract,pseudoexfoliation syndrome, glaucoma, corneal dystrophy, complicated cataract which includes lens induced glaucoma, post uveitic cataract, subluxated lens, etc., previous intra-ocular surgery, intraoperative complications during cataract surgery, high myopia and high hyperopia, age younger than 40 years, preoperative endothelial cell count less than 1,000 cells per square millimeter, patients lost to follow up are not included in study.

 Outcomes

Primary outcome – Morphological changes will be seen in endothelial cells, increase central corneal thickness and increase central macular thickness post-operatively after uncomplicated phacoemulsification surgery. We expect a morphological change in endothelial cells, increase central corneal thickness and increase central macular thickness post-operatively after uncomplicated phacoemulsification surgery. We are examining a sample size of 95 patients preoperatively and post operatively.

Sample size calculation: N =

Sample size for mean difference (Single arm) n 1 = n 2 = Z α + Z β 2 σ m 2 2 ε − δ 2

Z α = 1.64

α = Type I error at 5%

Z β = 0.84

β = Type II error at 20%

σ m = std.dev

ε = True Difference in means

Mean 1 st group =236.28, Mean 2 nd group = 235.58 (Before & After).

True difference between two treatment groups before & after for effect in Central foveal thickness = 0.7

Mean Difference in reference treatment = 0.7

Standard Deviation = 4.7

(as Per Reference article)

And clinically, relevant difference (δ) = 2.4 (Assumed for Superiority)

(Assumed 20% decrease) as per reference article values ε − δ = 1.7 N = 2 ∗ 1.64 + 0.84 2 ∗ 0.07 2 / 2 − 0.7 − − 2.4 2 = 95 per group

(Reference Article): Akkaya et al., Central macular thickness after phacoemulsification surgery.

 Analysis

Descriptive statistics will be tabulated & presented over frequency & percentage for categorial assessment and over mean & standard deviation for quantitative assessment The mean and standard deviation of the outcome variables’ data will be examined for normal distribution. The interquartile range (IQR) and skewed distributions will be found using median statistics. For descriptive statistics, categorical and binary variable frequencies and percentages will be tallied. All the results will be performed & calculated using R-software free version. The analysis of the inferential statistics will follow the guidelines.

Dissemination – Planning to Publish In indexed journal and present the study in National Conference Proceedings.

Study status – The Recruitment of participants is yet to be started.

 Ethical considerations

Institutional Ethical Clearance has been obtained on

IEC No – DMIMS (DU)/IEC/2022/200

CTRI Registration was done – 25/07/23

CTRI reference Number – REF/2023/07/070915

Data availability

There are no data associated with this study.

 Acknowledgements

I would like to acknowledge Mr Laxmikant Umate Sir, who has helped me in sample size calculation and data analysis planning.

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