|Year : 2019 | Volume
| Issue : 1 | Page : 14-24
Comparative study between the effects of different concentrations of methylcellulose on the corneal endothelium during phacoemulsification
Sherif M Akef Saleh, Rafiq M.F ELGhazawy, Amr I.S ElAwamry, Rania G Zaki Afifi
Department of Ophthalmology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
|Date of Submission||23-Dec-2018|
|Date of Acceptance||28-Dec-2018|
|Date of Web Publication||26-Apr-2019|
Sherif M Akef Saleh
Faculty of Medicine, Ain Shams University, Cairo
Source of Support: None, Conflict of Interest: None
Purpose To study the effect of different concentrations of methylcellulose on the corneal endothelium during phacoemulsification using specular microscopy.
Patients and methods Sixty patients with immature senile cataract were equally distributed into two groups according to the concentrations of hydroxypropyl methylcellulose (HPMC) used during phacoemulsification surgeries. In the first group, HPMC 2% was used, and in the second group, HPMC 2.4% was used. Preoperative and 1-month postoperative evaluations were done including visual acuity testing, slit lamp examination using Topcon SL-3C, intraocular pressure measurement using Goldmann Applanation Tonometer, fundus examination, and corneal endothelium assessment by Tomey Specular Microscope EM-3000.
Results Preoperatively, no significant difference was recorded in age, sex, visual acuity, intraocular pressure, and endothelial cell count among the two groups. Postoperatively, the two groups had a significant decrease in endothelial cell count, but the decrease was less in group 2 using methylcellulose 2.4% (13.494%) than in group 1 using methylcellulose 2% (14.515%). There was an equal and significant improvement in visual acuity in the two groups.
Conclusion Methylcellulose 2.4% and methylcellulose 2% were comparable in their ability to protect the corneal endothelium during phacoemulsification; in general, both viscoelastics can be effeciently and safely used in performing phacoemulsification.
Keywords: corneal endothelium, methylcellulose, phacoemulsification
|How to cite this article:|
Akef Saleh SM, ELGhazawy RM, ElAwamry AI, Zaki Afifi RG. Comparative study between the effects of different concentrations of methylcellulose on the corneal endothelium during phacoemulsification. J Egypt Ophthalmol Soc 2019;112:14-24
|How to cite this URL:|
Akef Saleh SM, ELGhazawy RM, ElAwamry AI, Zaki Afifi RG. Comparative study between the effects of different concentrations of methylcellulose on the corneal endothelium during phacoemulsification. J Egypt Ophthalmol Soc [serial online] 2019 [cited 2020 May 29];112:14-24. Available from: http://www.jeos.eg.net/text.asp?2019/112/1/14/257218
| Introduction|| |
The corneal endothelium consists of a single layer of hexagonal cells located in the back surface of the cornea. Anteriorly it is continuous with corneal stroma by Descemet’s membrane, and posteriorly it is in direct contact with the aqueous fluid filling the anterior chamber of the eye .
The endothelial layer of the cornea keeps up corneal transparency by guaranteeing it remains in a state of incomplete deturgescence. Adjacent cells have numerous lateral interdigitations and possess gap and tight junctions along their lateral cell membrane. The Na+/K+ ATPase pump is an essential component that exist with a high density on the endothelial cells lateral borders .
Endothelial cell thickness keeps on changing all throughout life. From childhood to eighth decade of life, the cell density decays from 4000 cells/mm2 to approximately 2600 cells/mm2. The focal endothelial cell thickness diminishes at a normal rate of 0.6% every year in typical corneas .
Endothelial cells have no mitotic action in vivo; be that as it may, people are brought into the world with a critical save. It has been seen that eyes with endothelial cell tallies underneath 500 cells/mm2 might be in danger for the advancement of corneal edema. Endothelial cell morphology also correlates with endothelial pump function. Variation in cell size (polymegathism) and variation in cell shape (pleomorphism) reflect poor endothelial function, which leads to an increasing risk of postoperative significant corneal edema and even corneal decompensation after phacoemulsification .
Specular microscopy is used to view and record the picture of the corneal endothelium .
Cataract medical procedure is a standout among the most as often as possible performed medication worldwide , and within the most recent decades, enormous upgrades have been made with respect to methodology and also the technology of phacoemulsification machines as well as the continuous update of additive tools that improve the postoperative results .
In this regard, the use of ophthalmic viscoelastic gadgets [ophthalmic viscoelastic device (OVD)] during the procedure has developed into the focal point of logical and clinical intrigue; OVDs can be valuable to keep up stable well-formed anterior chamber and can broaden and stabilize pupil size in poor dilating pupils thus minimize intraoperative complications .
OVDs may decrease substantial intraocular pressure (IOP) vacillations amid medical procedure. These variances are likely an inclining hazard factor for expulsive hemorrhage, and if an intraoperative back capsular tear happens, OVDs can encourage to push vitreous in reverse, facilitate to tamponade the vitreous posteriorly, and prevent vitreous prolapse into the anterior chamber, assisting intraocular lens (IOL) implantation relaying on the anterior lens capsule in the ciliary sulcus .
One of the fundamental viewpoints in OVD usage is assurance of intraocular structures specifically the corneal endothelium cells throughout phacoemulsification procedure, mostly owing to concealment of free radical formation .
Likewise OVDs play an important role in avoiding corneal endothelial contact with the iris, lens particles, surgical instruments, and IOL during and after the implantation process, and all of these risks can lead to irreversible endothelial cell loss .
| Aim of the work|| |
The aim is to study the effect of different concentrations of methylcellulose on the corneal endothelium during phacoemulsification using specular microscopy.
| Patients and methods|| |
Sixty patients with immature senile cataract are equally distributed into two groups according to the concentration of hydroxypropyl methylcellulose (HPMC) usage during phacoemulsification procedure. This study was completed in agreement to the fundamentals of the Declaration of Helsinki and performed according to the recommendations of Faculty of Medicine, Ain Shams University Research Ethical Committee.
Patients with senile nuclear cataract of grade II and grade III according to Lens Opacity Classification System  were included.
In the first group, HPMC 2% was used, and in the second group, HPMC 2.4% was used during the procedure.
Before the surgery, all the patients were subjected to complete ophthalmological examination including visual acuity testing, measuring of IOP using Goldmann Applanation Tonometer, slit lamp biomicroscopy that was done using Topcon SL-3C, and fundus examination.
Corneal edndothelium was assessed by Tomey Specular Microscope EM-3000 Specular microscopy.
The clinical examination and specular microscopy was done preoperatively and at 1-month postoperative to detect endothelial cell loss after phacoemulsification and to compare the protective effect of different concentrations of HPMC on the corneal endothelium during phacoemulsification procedure.
History of previous ocular surgery or trauma, History of uveitis or glaucoma, significant corneal scarring, or opacification corneal dystrophies were the exclusion criteria.
| Results|| |
The collected data were coded, tabulated, and statistically analyzed using IBM statistical package for the social sciences software (2013; IBM Corporation, Chicago, Illinois, USA).
Descriptive statistics were done for quantitative data as minimum and maximum of the range as well as mean±SD for quantitative data as number and percentage.
Inferential analyses were done for quantitative variables using independent t test in cases of two independent groups with parametric data and paired t test in cases of two dependent groups with parametric data.
The level of significance was taken at P value less than 0.05 as significant, otherwise nonsignificant. The P value is a statistical measure for the probability that the results observed in a study could have occurred by chance.
Regarding sex distribution, in group 1, there was 14 males and 16 females, whereas in group 2, there was 13 males and 17 females, with no significant difference between the two groups ([Table 1], [Figure 1]).
Regarding laterality distribution, in group 1, there were 21 right eyes and nine left eyes, whereas in group 2, there were 19 right eyes and 11 left eyes, with no significant difference between the two groups ([Table 2], [Figure 2]).
Regarding cataract grade distribution, in group 1, there were 24 nuclear cataract (NC) II cases and six NC III cases, whereas in group 2, there were 27 NC II cases and three NC III cases, with no significant difference between the two groups ([Table 3], [Figure 3]).
Comparing the age distribution of the two study groups, it was found that the mean age in group 1 was 61.733±6.074 years, ranging from 51 to 75 years, whereas in group 2, the mean age was 62.967±7.43 years, ranging from 50 to 78 years, with no significant difference between the two groups ([Table 4], [Figure 4]).
Comparing the best-corrected visual acuity (BCVA) in the two groups, we found that the mean preoperative BCVA in group 1 was 0.189±0.075, ranging from 0.1 to 0.3, and the mean postoperative BCVA was 0.557± 0.097, ranging from 0.5 to 1, whereas in group 2, the mean preoperative BCVA was 0.162±0.067, ranging from 0.05 to 0.3, and the mean postoperative BCVA was 0.59±0.121, ranging from 0.5 to 1. These results show significant increase in the BCVA postoperatively in both groups, with no significant difference between the two groups ([Table 5], [Figure 5],[Figure 6]).
|Figure 5 Pre-operative and Post-operative best corrected visual acuity in the two groups.|
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|Figure 6 Pre-operative and post-operative best corrected visual acuity in the two groups.|
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Comparing the IOP in the two groups ([Table 6], [Figure 7],[Figure 8],[Figure 9],[Figure 10]), we found that the mean preoperative IOP in group 1 was 16.647±1.833 mmHg, ranging from 12 to 19 mmHg, and the mean postoperative IOP was 15.2±1.883 mmHg, ranging from 10 to 18 mmHg. The mean IOP drop was 1.267±0.828 mmHg, ranging from 0 to 3 mmHg, and the mean IOP drop percentage was 7.715±5.319% ranging from 0 to 21.43%.
|Table 6 Preoperative and postoperative intraocular pressure comparison in the two groups|
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|Figure 7 Pre-operative and post-operative IOP comparison in the two groups.|
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|Figure 8 Pre-operative and post-operative IOP comparison in the two groups.|
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|Figure 10 IOP Drop Percentage in the 2 groups. IOP, intraocular pressure.|
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However, in group 2, we found that the mean preoperative IOP was 15.967±2.297 mmHg, ranging from 11 to 20 mmHg, and the mean postoperative IOP was 14.6±2.191 mmHg ranging from 10 to 18 mmHg. The mean IOP drop was 1.367±1.033 mmHg, ranging from 0 to 3 mmHg, and the mean IOP drop percentage was 8.428±6.32%, ranging from 0 to 20%. There was no significant difference between the two groups.
Comparing the endothelial cell count (ECC) in the two groups ([Table 7], [Figure 11],[Figure 12],[Figure 13],[Figure 14]), we found that the mean preoperative ECC in group 1 was 2488.367±180.835 ranging from 1865 to 2783 and the mean postoperative ECC was 2126.167±144.934 ranging from 1650 to 2330. The mean endothelial cell loss was 362.267±52.020 mmHg, ranging from 215 to 453 mmHg, and the mean endothelial cell loss percentage was 14.515±1.458%, ranging from 11.53 to 17.17%.
|Table 7 Preoperative and postoperative endothelial cell count in the two groups|
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|Figure 11 Pre-operative and post-operative endothelial cell count in the two groups.|
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|Figure 12 Pre-operative and post-operative endothelial cell count in the two groups.|
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However, in group 2, we found that the mean preoperative ECC was 2488.900±131.852, ranging from 2286 to 2742, and the mean postoperative ECC was 2153.233±119.219, ranging from 1966 to 2382. The mean endothelial cell loss was 335.667±21.170, ranging from 295 to 376, and the mean endothelial cell loss percentage was 13.494±0.667%, ranging from 12.36 to 14.69%.
These results shows a significant decrease in the ECC postoperatively (P=0.012).
| Discussion|| |
Since the presentation and the expanding use of the strategy of phacoemulsification, numerous investigations have been done to look at the viability of various viscoelastics (OVDs) in the assurance of corneal endothelium safety during the procedure.
In our study, we looked at the protective effect of two distinct convergences of hydroxypropyl methylcellulose on the corneal endothelium during the procedure: group 1 with utilization of the concentration of 2%, and the other group (group 2) with the utilization of the concentration of 2.4%.
The demographic statistic information was compared regarding age and sex of the patients in the two groups, demonstrating no significant difference. The mean age in group 1 was 61.73±6.07, and in group 2, it was 62.96±7.430. An important factor in the study is age, as there is a physiological decline of ECC and function with aging, and also the density of senile cataract increases with aging.
Preoperative specular microscopy ECC was compared in the two groups, with no significant difference between the two groups: group 1 mean ECC was 2488.367±180.835 ([Figure 1]a) and group 2 mean ECC was 2488.900±131.852 ([Figure 2]a).
Likewise postoperative ECC in the two groups using specular microscopy was compared, and there was significant difference between the two groups: group 1 mean ECC was 2126.167±144.934 ([Figure 1]b) and group 2 mean ECC was 2153.233±119.219 ([Figure 2]b).
The corneal endothelial cell loss was comparable in the two groups: in group 1, it was 362.267±52.020 (14.515±1.458%), and in group 2, it was 335.667±21.170 (13.494±0.667%) with slightly better safety protection in group 2.
These outcomes demonstrates that HPMC 2.4% gives preferable assurance protection over HPMC 2% on corneal endothelium during the phacoemulsification in terms of the postoperative ECC and the endothelial cell loss.
Various studies have been done to investigate the adequacy and protective effect of various viscoelastics during phacoemulsification procedure ,,,,,.
Maár et al.  conducted a study to evaluate the defensive effect of sodium hyaluronate 1% (Healon) and sodium hyaluronate 3%-chondroitin sulfate 4% (Viscoat) during phacoemulsification procedure. They demonstrated no significant difference among preoperative and postoperative endothelial cell thickness estimations in either group.
Another study was done in 1999 by Miller and Colvard  to look at the capacity of Healon GV (sodium hyaluronate 1.4%) and Viscoat (sodium chondroitin sulfate 4.0%-sodium hyaluronate 3.0%) to ensure the protection and safety of the corneal endothelium during phacoemulsification and foldable IOL implantation. It showed that there was no statistically significant difference between the two groups regarding pachymetry, ECC, or average endothelial cell size. However, Viscoat showed slight superior ability to preserve the hexagonality of endothelial cells over Healon GV.
Another research was done in 2012 by Espíndola et al.  to analyze the effects and results of two ophthalmic viscosurgical gadgets, DisCoVisc (1.6% hyaluronic acid, 4.0% chondroitin sulfate) and 2.0% hydroxypropyl methylcellulose, during phacoemulsification.
The data demonstrated that DisCoVisc (1.6% hyaluronic acid, 4.0% chondroitin sulfate) was increasingly effective and was less demanding to be removed after IOL implantation than 2.0% hydroxypropyl methylcellulose. Likewise, the corneal ECC was significantly higher after the utilization of hyaluronic acid/chondroitin sulfate than with hydroxypropyl methylcellulose, which demonstrated better security of the corneal endothelium.Moschos et al.  analyzed the corneal changes of Viscoat (sodium chondroitin sulfate 4.0%-sodium hyaluronate 3%) and Visthesia (sodium hyaluronate 1.5% and lidocaine hydrochloride 1%) in patients experiencing phacoemulsification. They proposed that Viscoat is increasingly sheltered and defensive for the corneal endothelium throughout the procedure, whereas Visthesia is in prevalent effective with respect to intraoperative agony. Patients of the two groups gained magnificent visual acuity postoperative.
Vajpayee et al.  compare the adequacy and safety of three ophthalmic viscosurgical gadgets that are routinely utilized in the procedure: Viscoat (sodium chondroitin sulfate 4.0% and sodium hyaluronate 3.0%), Healon GV (sodium hyaluronate 1.4%), and Healon 5 (sodium hyaluronate 2.3%).
They demonstrated that Viscoat, Healon GV, and Healon 5 give practically identical outcomes as far as viability and safety in performing the procedure is concerned, with no significant contrasts among the three groups in the postoperative corneal thickness or ECC.
Storr-Paulsen et al.  analyzed the protective effect of cohesive and dispersive OVDs, Celoftal (HPMC 2%), Vitrax (sodium hyaluronate 3%), and Healon (sodium hyaluronate 1%) on the corneal endothelium in phacoemulsification with implantation of a foldable posterior chamber IOL.
They demonstrated that each of the three groups had a significant loss in cell count; however, the decline was fundamentally less in the Vitrax gathering (6.97%) than in the Celoftal (18.03%) and Healon gatherings (18.46%). No changes in cell size, hexagonality, or corneal thickness were seen inside any of the three gatherings or among the gatherings. There was an equivalent and critical increment in visual keenness.
The referenced studies about the viability and the defensive effect of various ophthalmic viscoelastics demonstrated outcomes like our investigation with respect to the defensive effect of methylcellulose with its distinctive concentrations on the corneal endothelium during phacoemulsification, so the two concentrations (2 and 2.4%) can be utilized securely and adequately in the procedure to diminish the endothelial cell loss and guarantee the postoperative corneal lucidity, which gives the patients better visual outcomes and quicker recuperation.
| Conclusion|| |
The use of OVDs has become essential and important in modern cataract surgery by phacoemulsification to perform safer surgery and for better and faster visual recovery for the patients.
In our study, we compared the effect of different concentrations of methylcellulose (2 and 2.4%) on the corneal endothelium during phacoemulsification.
The study results showed postopertaive significant improvement in BCVA and significant endothelial cell loss in both study groups, but the results were comparable in both groups with no effect on the clinical outcomes.
So it is advised to use both concentrations of methylcellulose (2 and 2.4%) during phacoemulsification to protect the corneal endothelium, to perform the surgery with high safety profile, and to decrease the incidence of intraoperative complications, which leads to fast postoperative visual recovery and the ability to perform daily life activities in a normal way.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13], [Figure 14]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]