|Year : 2018 | Volume
| Issue : 1 | Page : 12-14
Comparison of effective phaco time and ultrasound time among 2.8 mm and 2.2 mm phacoemulsification in various grades of cataract
Lakshmi Bomalapura Ramamurthy, Kavitha Chikkanayakanahalli Venugopal, Pavana Acharya, Sahana Raviraj Manipur
Department of Ophthalmology, Hassan Institute of Medical Sciences, Hassan, Karnataka, India
|Date of Web Publication||18-Jan-2018|
Lakshmi Bomalapura Ramamurthy
Department of Ophthalmology, Room No. 705, HIMS Ladies Hostel, Hassan Institute of Medical Sciences, Hassan - 573 201, Karnataka
Source of Support: None, Conflict of Interest: None
Purpose: The purpose of this study is to compare the effective phaco time (EPT) and ultrasound time (UST) between phacoemulsification incisions of 2.8 mm and 2.2 mm among different grades of cataract and analysis of phacoenergy used. Materials and Methods: A prospective, interventional study was done on 300 eyes of 300 patients. Among them, 150 patients underwent 2.8 mm incision (Group-A), and 150 patients underwent 2.2 mm incision (Group-B) phacoemulsification. Cataract was graded into nuclear sclerosis (NS) 1–5 and white soft cataract. Phaco parameters were noted as EPT and UST in seconds. Statistical analysis was done using unpaired t-test using SPSS software. Results: Higher mean EPT and UST values were noted in 2.2 mm group than in 2.8 mm group in all grades of cataracts. On comparing the difference between two groups, higher mean values of EPT and UST in 2.2 mm incision were statistically significant in cataracts of NS Grade - 3, 4, and 5 (P < 0.001). However, the higher mean values in NS-2 and soft cataracts were statistically insignificant. Early postoperative striate keratopathy was noted in five patients in Group-A (2.8 mm) and ten patients in Group-B (2.2 mm). Conclusion: Dissipation of energy was higher in terms of EPT and UST in 2.2 mm group with statistically significant higher mean values in grades of NS-3, 4, and 5 concluding that 2.8 mm incision would be a safer option among higher grades of cataract.
Keywords: 2.2 mm incision, 2.8 mm incision, microincision cataract surgery, phacoemulsification
|How to cite this article:|
Ramamurthy LB, Venugopal KC, Acharya P, Manipur SR. Comparison of effective phaco time and ultrasound time among 2.8 mm and 2.2 mm phacoemulsification in various grades of cataract. J Clin Ophthalmol Res 2018;6:12-4
|How to cite this URL:|
Ramamurthy LB, Venugopal KC, Acharya P, Manipur SR. Comparison of effective phaco time and ultrasound time among 2.8 mm and 2.2 mm phacoemulsification in various grades of cataract. J Clin Ophthalmol Res [serial online] 2018 [cited 2018 Dec 14];6:12-4. Available from: http://www.jcor.in/text.asp?2018/6/1/12/223570
Cataract surgery is the most widely performed surgery worldwide. Phacoemulsification is the main procedure of modern cataract surgery. Cataract surgery is not simply a procedure to remove the opaque lens but aims at achieving best possible visual outcome with maximum safety and minimum invasiveness. These goals have created a trend toward a smaller wound from a 10 mm incision used for extracapsular cataract extraction to 2.8 mm–2.2 mm incisions in phacoemulsification that is associated with less surgically induced astigmatism (SIA), better fluidics, faster recovery, less tissue damage, and inflammation. Ultrasonic energy used during phacoemulsification can carry the risk of endothelial cell loss and tissue damage, especially in hard cataracts.
Many clinical studies are in place today comparing the effects of different phacoemulsification procedures and different grades of cataract., There is very little information available in literature comparing the phacoemulsification incisions and various grades of cataract. This study has been conducted in large scale comparing the phaco parameters and grades of cataract in two different incisions of 2.2 and 2.8 mm, respectively. With this background, we aimed at comparing effective phaco time (EPT) and ultrasound time (UST) between 2.8 mm and 2.2 mm incisions among different grades of cataract in phacoemulsification surgery.
| Materials and Methods|| |
A prospective, comparative interventional study was done on 300 eyes of 300 patients with various grades of cataract selected to undergo phacoemulsification surgery, during the study period of August 2014–March 2015. Considering our hospital phacoemulsification surgery statistics, time duration of the study, and calculation based on the present prevalence of cataract surgery rates, with a precision rate of 8%, a sample of 300 was considered in the study. Patients were allocated alternatively to each group comprising 150 subjects each. The study adhered to the Declaration of Helsinki and approval for the study was obtained from Institutional Ethics Committee.
Conventional phacoemulsification technique with 2.8 mm incisions was done on 150 patients and was classified as Group-A. Microincision cataract surgery (MICS) technique with 2.2 mm incision was done on 150 patients and was classified as Group-B. Both groups with 150 patients in each were interviewed for demographic data, and confirmation of ocular, systemic, and medical histories were undertaken.
The inclusion criteria included patients aged above 30 years with a transparent central cornea, pupil dilation at the preoperative examination of at least 6 mm, all grades nuclear cataract with normal fundus examination.
Patients with complicated/traumatic cataract or ocular pathologies, posterior segment pathologies, seropositive reports for human immunodeficiency virus, and hepatitis B surface antigen, with a history of the previous ocular surgeries, and any other ocular or neurological diseases that may affect visual acuity were excluded from the study.
All patients fulfilling inclusion and exclusion criteria were included in the study. Patients were explained about the preexisting condition of the eye, details of the procedure, and probable complications in their local language and informed consent was taken from the patients and their attenders. Patients were allocated into the two groups – Group-A (2.8 mm) and Group-B (2.2 mm) based in incision size.
Each patient underwent a routine ophthalmological workup that included visual acuity for near and distant vision, slit-lamp examination for anterior segment evaluation, intraocular pressure measurement, tropicamide dilatation followed by refraction and fundoscopy. Patients were posted for cataract surgery after ascertaining physician fitness.
All surgeries were performed by a single-experienced surgeon under peribulbar anesthesia after pupillary dilation with tropicamide 1%. A single planar clear corneal incision was created using a 2.8 mm metal tip knife in the conventional phacoemulsification group (Group-A) and a 2.2 mm metal tip knife in the microincision phacoemulsification group (Group-B). Two side ports were created using a 1.2 mm clear-cut side port knife. Phacoemulsification was done by AMO Sovereign Compact white star machine using direct chop technique, with Kelman 30-degree tip in both the groups and readings of phacomachine noted under headings – (1) EPT (2) UST in seconds. Phaco machine settings are depicted in [Table 1]. After effective emulsification, foldable intraocular lens (IOL) was injected with a suitable cartridge in both the groups and IOL was dialled. The anterior chamber formed and clear corneal incision wound hydrated and water sealed.
All patients were evaluated on postoperative day 1 for visual acuity with a special reference toward complications such as striate keratopathy and wound stability. Further, patient follow-ups were done on week 1, week 3, and week 6. In each visit, vision was documented and other complications if any were noted.
A comparative analysis was made regarding the different parameters of phaco machine for various grades of cataract in two types of incisions - 2.8 mm and 2.2 mm. Statistical analysis was done using SPSS software (version 18.0, SPSS Inc, IBM Corporation, Chicago, USA) to analyze the data, using unpaired independent sample t-test and P < 0.05 was considered statistically significant.
| Results|| |
The results of 300 eyes in both the groups were analyzed. Mean age group was 61 ± 3.2 years. There were 179 females and 121 males in the study. Group-A consisted of 79 males and 71 females, while Group-B consisted of 42 males and 108 females. Different grades of cataract in both the groups are shown in [Table 2].
The values of EPT and UST were recorded in seconds. These parameters were recorded for both the groups in all grades of cataract and are represented in [Table 3]. A significantly higher mean EPT and UST were obtained in Group-B (2.2 mm) for all grades of cataract with statistically significant difference in nuclear sclerosis (NS) Grades 3, 4, and 5, (P < 0.05) indicating more dissipation of energy in higher grades of cataract.
|Table 3: Effective phaco time and ultrasound time values for various grades of cataract in both groups (s)|
Click here to view
The difference of mean values of EPT and UST in NS2 and soft white cataract was statistically insignificant. Early postoperative striate keratopathy was noted in five patients in Group A (2.8 mm) and ten patients in Group B (2.2 mm), which resolved over a span of 1–2 weeks. No other complications were observed during the study.
| Discussion|| |
Incision of 2.8 mm phacoemulsification represents conventional coaxial phacoemulsification technique while 2.2 mm phacoemulsification represents a new level of development as MICS. According to Jeong et al., an incision of 2.2 mm, sustained more ultrasound exposure and prolonged case time, causing moderate postoperative corneal edema. We found that there was more dissipation of energy in 2.2 mm incision group with higher EPT and UST in all grades with statistically significant difference in Grades 3, 4, and 5, but this difference was statistically insignificant in grade 2 and white soft cataract. This higher dissipation of energy in 2.2 mm group could be attributed to fluid hindrance in 2.2 mm group leading to more exposure of ultrasound energy.
A study by Dosso et al. on comparing the outcomes of coaxial microincision cataract surgery versus conventional coaxial cataract surgery gives statistically significant differences among the two groups with respect to UST (P = 0.0002) and surgical time (P = 0.005), being higher in MICS. In this continuum, our study also shows significant difference not only in UST but also in EPT and mean percentage of energy dissipated in 2.2 mm group.
Wang et al. in comparing different incisions in phacoemulsification opines that the reduction of incision size from 2.6 mm to 2.2 mm offered no greater reduction of SIA. With reference to above study, 2.8 mm conventional incision would not cause significant SIA. Hence, in harder grades of cataract, 2.8 mm would prove to be a safer option in view of lesser energy dissipation. A study by Kahraman et al. and Wilczynski et al. in comparing surgical trauma and endothelial cell loss among MICS and conventional phacoemulsification mentions that there is more postoperative corneal swelling in MICS group along with increased endothelial cell loss even though it was statistically insignificant., In this context, our study supports by showing relatively more cases of postoperative striate keratopathy in 2.2 mm group. However, we did not consider endothelial cell count in our study.
Considering the pros and cones of both the incisions, it can be opined that 2.2 mm would be a better option up to nuclear Grade 2 or 3 while harder cataract warrants 2.8 mm incision phaco for lesser dissipation of energy in view of better outcome.
The outcome of energy dissipated would have been better assessed by considering endothelial cell count. However, due to unavailability of the equipment, this could not be assessed. Considering SIA into the study would have made the comparison more comprehensive. Since the previous studies have already established the minimal difference of astigmatism among 2.8 mm and 2.2 mm, this was not included in the study.
| Conclusion|| |
Conventional 2.8 mm incision and microincision of 2.2 mm can be employed in phacoemulsification procedure. However, there was more dissipation of energy in terms of EPT and UST in 2.2 mm group for harder cataracts. There was statistically significant higher mean EPT and UST values in NS Grades - 3, 4, and 5 in 2.2 mm group conveying that 2.8 mm can be considered as a safer option for harder cataracts.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]