Study on Outcome of Phacoemulsification Cataract Surgery with Clear Corneal Steep Axis Incision

A prospective, observational study was conducted in the Department of Ophthalmology, Combined Military Hospital (CMH), Dhaka, Bangladesh, from April to October of 2019, to observe the outcome and determine the amount of surgically induced astigmatism in phacoemulsification cataract surgery done with clear corneal incision. A total of 60 patients were included in this study. Cataract extraction was done in all the patients by phacoemulsification through clear corneal incision with foldable intraocular lens implantation. All the surgeries were done with INTREPID Micro-Coaxial system using the INFINITI Vision system by the same surgeon under local anaesthesia. The patients were followed up on 1st, 7th, and 30th POD. The parameters recorded were uncorrected visual acuity, best-corrected visual acuity, slit lamp examination, and keratometry. Due to clear corneal incision on steep axis, the steep meridian became flat, from 44.329±1.473D (diopter) (as found in pre-operative keratometry) to 43.971±1.431D (on the 30th post-operative day). On the other hand, the flat meridian became steeper from 43.225±1.471D (pre-operative) to 43.225±1.501D (on the 30th day). At preoperative examination and 30th day follow-up visit, astigmatism was determined as 1.10±0.319 and 0.583±0.413 respectively. The change of astigmatism was statistically significant (P<0.05).


Introduction
Cataract is the leading cause of visual impairment and blindness in the world.There are various methods of cataract extraction, of them small incision cataract surgery (SlCS), and phacoemulsification cataract surgery are widely performed. 1Currently, phacoemulsification with posterior chamber intraocular lens (PCIOL) implantation is the most popular treatment modality for cataract.With the improvement in surgical techniques and the development of new technology, the recovery of visual function after cataract surgery has significantly improved.In the posterior chamber, phacoemulsification reduced endothelial cell loss while viscoelastic protected the cornea. 2In addition, the advent of foldable intraocular lenses (lOLs) has led to better results.
3 Visual rehabilitation after phacoemulsification largely depends on corneal astigmatism. 4In astigmatism, the rays of light cannot be made to produce a point image on the

Methods
This prospective, observational study was

Results
A total of 60 patients were included in the study.
Their age ranged between 40 and 75 years and most of the patients belonged to 52-63 years age group.Among the study patients, males were 42(70%) and females were 18(30%) and the male-to-female ratio was 2. As a result, an astigmatic person's vision is not as good as that of those who do not have astigmatism.Therefore, astigmatism significantly affects a patient's independence, quality of life, and well-being.Hence, the results could not be generalized for the country's population.We recommend further studies with larger samples with longer duration and in multi-centre to draw a better inference.

Hayashi K, Hayashi
conducted in the Department of Ophthalmology, Combined Military Hospital (CMH), Dhaka Cantonment, Dhaka, Bangladesh, between April and October of 2019.Inclusion criteria: 1. unilateral or bilateral age-related cataract, 2. between 40 and 75 years of age. the patient is unwilling to go through the procedure, 7) any cognitive disorder or psychiatric issues.A total of 60 patients who fulfilled the selection criteria for phacoemulsification cataract surgery CBMJ 2024 January: Vol. 13 No. 01 with IOLs implantation were included in the study.Under local anaesthesia, proper surgical toileting of the operation field was done with 5% povidone iodine and draped with sterile sheets and eye drapes.After properly exposing the operative field, the main incision was given.The clear corneal tunnel incision was performed with the side-port at 70 degree apart and to the left side of the main incision.The tunnel incision was done in all patients with a 2.4 mm Webal Edge knife and the side port with a 1.2 mm Webal edge knife.After continuous curvilinear capsulorrhexis and hydrodissection, the nuclear rotation and emulsification were done.In all patients, a 0.9 mm mini-flared ABS Kelman tip with a 45 degree bevel was used for phacoemulsification. 8 The cortical matter was removed by irrigation and aspiration techniques.Then a foldable IOL was implanted in the capsular bag.All incisions were left suture-less and were sealed by corneal stromal hydration.Patients' follow up was done on the 1st, 7th and 30th postoperative days (POD).A slit lamp examination and ophthalmoscopy were done routinely.Data was collected in a predesigned data collection sheet.All the data were doublechecked, compiled, and sorted properly.Appropriate statistical analysis was done using computer-based SPSS (Statistical Package for Social Science) software version 26.0, for windows.

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The change in the keratometric cylinder was examined by the simple subtraction method of calculating cylinders without regard to axis.Due to a clear corneal incision on the steep axis, we found that the mean (±SD) steep meridian became significantly flatter from preoperative keratometry 44.329 (±1.473)D to the 30th POD keratometry 43.971(±1.431)D. On the other hand, the mean (±SD) flat meridian became steeper from preoperative keratometry 43.225(±1.471)D to 30th POD keratometry 43.421(±1.501)D. Therefore, the pre-existing astigmatism reduced gradually over time.This study was compatible with the study done by Beltrame et al.; they showed significant woundrelated flattening and non-orthogonal steepening in 2 opposite radial sectors induced by different oblique cataract incisions.10 We found that preoperative mean (±SD) astigmatism was 1.104(±0.319)D. During postoperative follow-up on the 1st, 7th, and 30th PODs, mean astigmatism decreased to 0.954±0.494D, 0.708±0.407D, and 0.583±0.413D respectively.Thus, the mean preoperative astigmatism decreased significantly in the successive postoperative days.This study was compatible with the findings of Borasio et al., who showed the on-axis CCI induced flattening of the meridian of the incision at a mean of 0.63 D; however, the results were observed after eight weeks. 11Another study was done in the same institution and observed similar findings, i.e., after cataract surgery astigmatism was significantly decreased over time.12 CBMJ 2024 January: Vol. 13 No. 01 Conclusion Cataract surgery as a form of refractive surgery demands uncorrected, high-quality vision postoperatively.Ophthalmologists planning to provide quality vision for the patient after cataract surgery by phacoemulsification would be prudent to adopt the best-suited procedure to minimize the pre-existing astigmatism for the individual patient.As a result, in phacoemulsificationsurgery, an on-axis clear corneal incision may be a good option for significant correction of pre-existing corneal astigmatism.We had some limitations in our study.The follow-up schedule was short, and the sample size was small.