This was a hospital based prospective interventional study conducted over a period of 6 months (March 2019 to August 2019) and was conducted in the Department of Ophthalmology at Acharya Vinobha Bhave Rural Hospital, Sawangi, Wardha, Maharashtra.

This study was approved by the Institutional Ethics Committee of the University (Ref. DMIMS (DU)/IEC/01/7892) and was carried out in accordance with the declaration of Helsinki. 25 patients were in Group I (ocular viscoelastic device used) and 25 patients were in Group II (balanced salt solution via anterior chamber maintainer used).

All patients with cataract, attending the Ophthalmology Outpatient Department at Acharya Vinobha Bhave Rural Hospital were selected for the study after taking the inclusion and exclusion criteria into consideration.

Inclusion criteria: Patients presenting with cataract (Nuclear sclerosis grade II) during the study period; Age-50-70 years.

Exclusion criteria: Patients having other pre-existing corneal conditions (dystrophies, degenerations, scars) that might independently decompensate corneal endothelium. Patients with inflammatory diseases such as iritis. Patients with any retinal pathology (exudative age-related macular degeneration, proliferative diabetic vitreoretinopathy, retinal ischemic diseases). Patients with glaucoma (open angle, secondary). Patients with floppy iris syndrome and patients on Tamsulosine.

Patients who fulfilled the inclusion criteria and were not eliminated under the exclusion criteria were admitted to the Ophthalmology ward. After explaining the details of the study, written informed consent was taken from them. A single experiences surgeon performed all the surgeries.

Data collection tools and process: The patients age, sex and ocular history were noted. Visual acuity pre and post surgery as well as post operative complications, if any, were documented.

Preoperative: Written consent was taken from the patients willing for and fit for cataract extraction. Endothelial cell density and the % of hexagonal endothelial cells was measured at the central cornea using a noncontact specular microscope at a resolution of 640×480 pixels (TOPCON SP 1P08). All measurements were done by one person at a single clinical site.

Steps of surgery: The eye was fully dilated using E/D Tropicamide 0.8% + Phenylephrine 5%. Topical anaesthesia was given using E/D Proparacaine 5%. The eye speculum was then placed. Two clear corneal incisions of 1.1 mm were made with 15-degree lance tip near to the limbus. Two incisions were made- at 2’o’clock and at 10’o’clock. An anterior chamber maintainer of 1.1 mm diameter connected to a balanced salt solution bottle (80-95 cm above the patients head level) was introduced though the 2’o’clock incision and the irrigation was turned on in order to maintain a deep anterior chamber. The anterior chamber maintainer fit in the 2’o’clock incision such that there was no leakage.

In 25 patients (Group I) capsulorhexis was performed using viscoelastic device (OVD) to maintain a stable and safe space to work while in 25 (Group II) patients BSS circulation in the anterior chamber by means of the irrigation cannula which produced a positive pressure, was used for the same.

A 2.8 mm keratome was used to make a clear corneal incision at 12 ‘o’clock. After that, hydrodissection was performed with hydro cannula until a complete rotation of the nucleus was observed Then, phacoemulsification, aspiration and mass extractions were performed. Only foldable One-piece Intraocular Lens (IOLs) model with injector was used. Balanced salt solution flowed out of the anterior chamber when the intraocular lens cartridge was introduced though the incision. This resulted in a momentary shallowing of the anterior chamber. As the IOL injection began, the leakage stopped. The anterior chamber depth was maintained and the positive pressure expanded the capsule. As the IOL unfolded, a cannula was used to fix it in place. Corneal hydration was done followed by placing an eye pad and bandaging the eye.

Postoperative: The pad and bandage were opened the next day and vision was assessed using Snellen’s chart. Port operatively the following medications were prescribed- T. Ciprofloxacin 500 mg BD for 3 days, T. Ibuprofen 400 mg BD for 3 days, T Ranitidine 150 mg BD for 3 days, E/D Moxifloxacin 0.5 % + E/D Dexamethasone 0.1% 1 hourly for 2 weeks followed by QID for 2 months and E/D Homatropine 2% BD for 1 week. Patients were followed-up on 14th postoperative day for assessment of corneal endothelium using specular microscopy.

Statistical analysis was done by using descriptive and inferential statistics using Student’s paired and Unpaired t-test and software used in the analysis was SPSS 24.0 version and p<0.05 was considered as level of significance.

Overall mean phacoemulsification time, phacoemulsification energy, phacoemulsification suction time was similar in all the patients and all surgeries were conducted by a single surgeon. Mean surgical time and irrigation-aspiration suction time were marginally similar in both the groups [Table/Fig-1].

Out of the 25 patients in Group I 15 (60%) were male and 10 (40%) were female. Out of the 25 patients in Group II 13 (52%) were male and 12 (48%) were females. The mean age of the patients was 61.35±1.23 years. There were no intraoperative or postoperative complications.

The preoperative and 14^th day postoperative corneal endothelial cell count is depicted in [Table/Fig-2]. Both the groups showed a significant decrease in corneal endothelial cell count (p-value=0.001). The difference between the mean decrease in corneal endothelial cell count of the two groups was not significant (p-value=0.10) [Table/Fig-3].

The preoperative and 14^th day postoperative hexagonality of the corneal endothelial cells showed a significant decrease in percentage of hexagonal cells (p-value- 0.001) [Table/Fig-4].

The difference between the mean decrease in percentage of hexagonal cells of the corneal endothelium of the two groups was not significant (p-value=0.32) [Table/Fig-5].

As compared to preoperative values, Group I and Group II showed a significant decrease in corneal endothelial cell count and percentage of hexagonal cells postoperatively (p=0.001). There was no significant difference between the two groups in terms of the decrease in cell count and percentage of hexagonal cells caused postoperatively (p-value=0.01).

Erden Y et al., in their study concluded that although the postoperative differences in CECs were similar in the visco as well as the BSS study groups, the surgical time was significantly shorter in the BSS Group. This would result in the added advantage of shorter surgical time and the possibility of performing a greater number of operations and thus a more cost-effective use of the operating room [13]. The difference in surgical time could be due to the fact that in their study all grades of cataract were included. In our study only cataracts with Grade II nuclear sclerosis were used to maintain uniformity.

Oksuz H et al., described a technique to perform capsulorhexis without viscoelastic, but IOL implantation was done with the use of viscoelastic and they concluded that this was an easy, safe and cheap alternative to using Viscoelastic. They achieved a complete capsulorhexis. They compared the IOP pre and postoperatively (day 1) and found a significant increase (p-value <0.05). The IOP reduced to preoperative levels by one week [14].

Studeny P et al. reported a 1 month and 6 month post-operative reduction in endothelial cell density of 9.76%±13.5%, 10.7%±12.6%, respectively in the OVD group and 9.07%±12.7%, 9.13%±13.7%, respectively in the hydroimplantation group. The difference between the two were insignificant [15]. This was similar to the findings seen in the present study which also showed no significant difference between the two groups.

Techniques of using viscoelastic only during continuous curvilinear capsulorhexis or only during IOL implantation have been described. In the index study, the corneal endothelium of the patients in Group II was not exposed to visco throughout the procedure as both continuous curvilinear capsulorhexis and IOL implantation were performed with continuous infusion of BSS via AC maintainer.

The corneal endothelial cell density and the percentage of hexagonal cells are indices to assess the quantity and quality of the corneal endothelium respectively, which is why we have chosen to study these two parameters.

The present authors have included only patients with Grade II nuclear sclerosis in the present study to ensure uniformity, so that the grade of cataract does not influence the surgical time and energy used which in turn might influence the endothelial cell count and hexagonality.

Minor complications like mild corneal epithelial oedema and mild aqueous flare can interfere with the assessment of the corneal endothelium. The cornea was assessed on the 14^th postoperative day so that in case these minor complications occurred postoperatively, they would settle by the 14^th postoperative day. Furthermore, the present authors did not want other confounding factors (such as age related loss of corneal endothelial cells) to influence our results, which is why we have chosen a single and shorter follow-up date.

The study by Lee HY et al., had similar results to this study, but they compared the high viscosity OVD Amvisc Plus^™ (Bausch & Lomb Incorporated, Bridgewater, NJ, USA) with BSS during hydrophilic acrylic IOL implantation and found a decrease of ~3% after 3 months without significant differences between both groups [16].

Milla E et al. reported the difference between phacoemulsification with and without AC infusion. The anterior chamber was maintained during phacoemulsification using the continuous irrigation option through the phaco probe. OVD was used in both groups and it was found that the endothelial cell density was significantly reduced on day 7 in the continuous infusion group. By day 30 there was no statistically significant difference between the two groups. In the present study, authors found no statistically significant difference on day 14 in endothelial cell loss [17].

Nayak BK and Jain EK, found no statistically significant difference in the corneal endothelial cell loss between the ACM without OVD’s (7.38%) and the OVD (7.47%) group measured one month post-surgery. This was similar to the findings of the index study [18].

In a study conducted by Wang H et al., it was found that at 1 week, 1 month, and 6 months after surgery, the percentage of corneal endothelial cell loss of the group with no viscoelastic device was significantly lower than that of conventional viscoelastic device group and at each postoperative time point, the corneal endothelial hexagonal cell density was significantly greater in the former than the later. In their study, they used Viscoelastic in both groups during the continuous curvilinear capsulorhexis step and IOL implantation was done by a viscoless technique in one of the groups. This was different from the method used in this study, where all steps of the surgery were done without visco in Group II. This might have caused a difference in the results [19].

Schulze SD et al., found no additional benefit in the use of OVDs during IOL implantation using a single-hand injector and a hydrophilic acrylic IOL. They found no significant difference in the decrease in corneal endothelial cell count between their two study groups [20].

A bigger sample size and a longer follow-up period is required to study any delayed implications of the use of OVD and BSS on the corneal endothelial morphology and cell count. This study included patients having Grade II nuclear sclerosis and so the results might not stand true for other grades of cataract and complicated cataract.

Phacoemulsification with the use of continuous balanced salt solution infusion via anterior chamber maintainer is an efficient alternative to ocular viscoelastic device. We can also conclude that when an experienced surgeon performs the surgery, there isn’t a significant difference in endothelial cell count or change in cell morphology when surgery is done with the use of continuous infusion with balanced salt solution as compared to when it is done with ocular viscoelastic device.