Endothelial cell loss analysis in phacoemulsification versus small incision cataract surgery: A randomised study

AIM:

To evaluate and compare endothelial cell changes in eyes undergoing phacoemulsification or manual small incision cataract surgery.

 OBJECTIVES:

PRIMARY OBJECTIVE:

To evaluate and compare endothelial cell changes in eyes undergoing phacoemulsification or manual small incision cataract surgery.

SECONDARY OBJECTIVE:

1. To compare the post-operative best corrected visual acuity (BCVA) in both the groups.

2. To correlate the average phacoemulsification time (APT) used in phacoemulsification group with endothelial cell loss

3. To compare the results in different axial length groups

MATERIAL  AND METHODS:

Study setting:

Study will be conducted in Department of Ophthalmology, King George’s Medical University, Lucknow and patients will be recruited from OPD. Informed consent will be taken in each case.

Study design:

This study is to be conducted after ethical approval. It is a tertiary care hospital based, prospective, randomized, parallel group study to compare endothelial cell loss in phacoemulsification and manual small incision cataract surgery.

Inclusion Criteria

·        Senile cataract of Nuclear grade III-V (LOCS III classification)

 Exclusion Criteria:

•      Endothelial cell density less than 1500 cells/mm3

•      History of previous ocular surgery

•      Any other coexisting ocular disease

•      Intraoperative surgical complication

 Sample sixe:

152 patients were recruited

Charan Biswas Formula ; n=z(1-α/2)2p(1-p)/d2

z(1-α/2)2 =1.96 at 95% CI

p( prevalence) = 1.2 %

d(margin of error) = 5%

n (sample size)=266

Due to COVID-19 pandemic and Nationwide lockdown, the patient recruitment and follow-up was adversely affected. Therefore, the calculated sample size could not be met. A total of 152 patients were contrived for the study.

METHODOLOGY:

Preoperative evaluation

The patients will be randomized by computer generated random number allocation.

Endothelial cell count, average size of cells, hexagonality, corneal cell thickness will be measured using specular microscope. Fixed frame analysis method will be used to capture the central area of cornea and four paracentral areas. Keratometry will be performed using IOL Master and axial length of eyes will be measured by  A scan ultrasound probe.

Postoperative evaluation

The patients will be divided into 3 groups based on their axial lengths- small, moderate and large. Postoperatively, assessment will be performed at 6 weeks. At follow up visit- visual acuity, anterior segment slit lamp examination, fundoscopy, and specular microscopy will be performed to evaluate the corneal endothelium. Non parametric tests will be used to find significance among the axial lengths, pre- and post-operative endothelial cell count, average size, hexagonality, corneal thickness and visual acuity in the two study groups. A probability value of 0.05 will be accepted as the level of statistical significance. P <0.05 will be considered statistically significant.