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 Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 57  |  Issue : 4  |  Page : 275-278

Capsulorhexis flap dimensions between manual continuous curvilinear capsulorhexis and zepto-assisted capsulotomy: A prospective study


Department of Ophthalmology, M. N. Eye Hospital, Chennai, Tamil Nadu, India

Date of Submission22-Oct-2019
Date of Decision24-Oct-2019
Date of Acceptance30-Oct-2019
Date of Web Publication26-Dec-2019

Correspondence Address:
Dr. R L Naveena
M. N. Eye Hospital, 781, T. H. Road, Tondiarpet, Chennai - 600 021, Tamil Nadu
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/tjosr.tjosr_93_19

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  Abstract 


Purpose: The purpose of this study is to compare rhexis flap dimensions between manual continuous curvilinear capsulorhexis (CCC) and zepto-assisted capsulotomy. Methods: A prospective study including consecutive 10 patients of CCC and consecutive 10 patients of zepto capsulotomy. Two methods were used to compare the CCC and zepto capsulotomy flaps. In the first method, digital caliper was used to compare the vertical and horizontal dimensions of the CCC and zepto flaps under microscope. In the second method, New Eyes software was used to measure the rhexis flap dimensions from the postoperative slit-lamp photo. Dilated slit-lamp photograph is captured and capsulorhexis size, shape, continuity, and intraocular lens (IOL) optic coverage was evaluated. Results: The t-test was used for the statistical analysis. The mean difference between the flap dimensions in the two groups is not statistically significant. The coefficient of variation is more in manual than the Zepto method for all the parameters, i.e., DC_VL (10.0% vs. 0.6%); SW_VL (12.5% vs. 0.8%); DC_HL (14.2% vs. 0.3%); and SW_VL (19.0% vs. 0.3%). Discussion: Zepto-assisted capsulotomy is very precise and has a good predictability and repeatability. Complications can be related to technique. Both methods ensure optimal IOL-optic coverage, but the repeatability of rhexis dimensions is more with zepto than CCC.

Keywords: Cataract surgery, continuous curvilinear capsulorhexis, precision pulse capsulotomy, rhexis, zepto capsulotomy


How to cite this article:
Nivean M, Naveena R L, Nishanth M, Nivean P, Nishanth S. Capsulorhexis flap dimensions between manual continuous curvilinear capsulorhexis and zepto-assisted capsulotomy: A prospective study. TNOA J Ophthalmic Sci Res 2019;57:275-8

How to cite this URL:
Nivean M, Naveena R L, Nishanth M, Nivean P, Nishanth S. Capsulorhexis flap dimensions between manual continuous curvilinear capsulorhexis and zepto-assisted capsulotomy: A prospective study. TNOA J Ophthalmic Sci Res [serial online] 2019 [cited 2020 Jan 19];57:275-8. Available from: http://www.tnoajosr.com/text.asp?2019/57/4/275/273994




  Introduction Top


Cataract surgery is the most commonly performed ophthalmic procedure worldwide with major anatomical and optical goal being, a well-centered posterior chamber intraocular lens (IOL). Anterior capsulotomy has evolved from an era of the can-opener capsulotomy to continuous curvilinear capsulorhexis (CCC) and more recently to precision pulse anterior capsulotomy. A smooth-edged capsulotomy renders the capsular bag opening its strength, for subsequent steps of phacoemulsification and is considered ideal if it is round, continuous, well-centered, and overlaps the IOL around its circumference. This study aims to compare rhexis flap dimensions between manual CCC and zepto-assisted capsulotomy. Manual CCC as described by Gimbel and Neuhann[1] is a circular, central, curvilinear opening in the anterior capsule. Manually, the capsulorhexis [Figure 1] can be fashioned by creating a small tear in the center of the anterior capsule and later advancing the resulting capsular flap into a circular shape by guiding the leading edge with the needle cystotome.[1] Continuous curvilinear capsulorrhexis may decrease the rate of posterior capsular opacification, especially if biconvex or posterior convex IOLs, which remain closely apposed to the capsule are used.[2]
Figure 1: Manual capsulorhexis

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Zepto capsulotomy or precision pulse capsulotomy system uses a nonlaser highly focused, fast, multipulse, low-energy discharge, which provides a reproducible, precisely automated, and fairly affordable technology to perform CCC. Zepto capsulotomy is performed using a device with a soft collapsible tip and circular Nitinol cutting element that is connected to a control console.[3] Nitinol being superelastic allows the capsulotomy tip to be collapsed into a narrower and elongated shape for entry through a clear corneal incision of 2.2–2.4 mm. It, later on, re-expands automatically to its original circular shape within the anterior chamber (AC). PPC system delivers a brief series of fast electrical pulses over 4 ms, which prevents any heat dissipation beyond the Nitinol ring.[4] The tip is fully inserted into the AC maintained by ophthalmic visco surgical devices and is gently opposed to capsular surface without any undue pressure. Suction is applied through the suction cup which ensures uniform application of energy to anterior capsule. After anterior capsulotomy has been performed and subsequently suction is reversed automatically, the tip is taken out.

Zepto system [Figure 2] has been observed to achieve a clean anterior capsulotomy in all kinds of cataracts and is especially useful for complicated cases with intumescent or brunescent lenses, zonulopathy, small pupils, and cases of cataract with corneal opacity.[3] Chang et al. 2016[3] reported PPC to be equally safe and with no greater zonular stress compared with CCC in human cadaver eyes. PPC technique claims to have a short learning curve and success even in challenging cataract cases with reported consistent creation of a round, appropriately sized capsulotomy.[5]
Figure 2: Zepto device

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Thompson et al.[6] compared the anterior lens capsulotomy edge tear strength created by manual CCC, femtosecond laser capsulotomy, and automated Zepto device. The strength of PPC capsulotomy edge was found to be significantly stronger than that produced by femtosecond laser or manual CCC. This may be due to the rolled edges of the capsulotomy after the energy has been applied to the capsule. Hooshmand et al.[7] evaluated the clinical safety and performance of PPC device in 100 eyes having cataract surgery. They reported a high incidence of incomplete capsulotomy and radial tear rate that was possibly associated with the use of a dispersive OVD. They also found that edges of the capsulotomy were frayed when capsulotomy specimens were evaluated by scanning electron microscopy and by clinical examination of patients during the postoperative period.[8]

Methods

This prospective study was done in a tertiary eye care center in South India. Patients undergoing phacoemulsification cataract surgery either by conventional CCC with a bent 26G cystotome or zepto-assisted capsulotomy were recruited for the study. Consecutive 10 patients of CCC and consecutive 10 patients of Zepto capsulotomy were included in the study. Eyes with Pseudoexfoliation syndrome, pupil dilation <6 mm, shallow AC <2.5 mm for zepto, and Calcified ALC were excluded from the study. Two methods were used to compare the CCC and zepto capsulotomy flaps. In the first method, digital caliper was used to compare the vertical and horizontal dimensions of the CCC and zepto flaps under microscope [Figure 3]a, [Figure 3]b, [Figure 3]c, [Figure 3]d, [Figure 3]e, [Figure 3]f and [Table 1]a and [Table 1]b. In the second method, New Eye Software from Shanghai, China. Software was used to measure the rhexis flap dimensions from the postoperative slit-lamp photo [Figure 4]a and [Figure 4]b and [Table 2]a and [Table 2]b. The dilated slit-lamp photograph is captured, and capsulorhexis size, shape, continuity, and IOL optic coverage were evaluated. The IOL centration and coverage were assessed on the basis of coverage of IOL optic in all four quadrants by the capsulotomy/capsulorhexis margin. Continuity of the capsulorhexis refers to the absence of radial extension or tear of the capsulorhexis edge.
Figure 3: (a-f) Digital caliper - Rhexis measurement

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Figure 4: (a) New Eyes Software measurement – Continuous curvilinear capsulorhexis. (b) New Eyes Software measurement – Zepto

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  Results Top


Capsulorhexis characteristics in the two groups such as the vertical and horizontal diameter of rhexis flap and shape were compared.

The t-test was used for the statistical analysis. The mean difference between the flap dimensions in the two groups is not statistically significant [Table 3] and [Table 4].
Table 3: Digital Caliper measurement summary

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Table 4: Neweyes software measurement summary

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However, the coefficient of variation is more in manual method than the Zepto method for all the parameters, i.e., Digital Caliper-Vertical-DC_VL (10.0% vs. 0.6%); Digital Caliper-Horiontal-DC_HL (14.2% vs. 0.3%); Software measurement-vertical-SW_VL (12.5% vs. 0.8%); Software measurement-horizontal-SW_VL (19.0% vs. 0.3%) [Table 3] and [Table 4].


  Discussion Top


Zepto-asssited capsulotomy is very precise and has good predictability and repeatability. Complications can be related to the technique.

  • Manual CCC is as good as zepto and ensures optimal IOL optic coverage when done by an experienced surgeon
  • Both methods ensure optimal IOL-optic coverage, but the repeatability of rhexis dimensions is more with zepto than CCC
  • Optimal IOL-optic coverage ensures proper centration of IOL and the prevention of PCO, which is achieved by both techniques.


Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Gimbel HV, Neuhann T. Development, advantages, and methods of the continuous circular capsulorhexis technique. J Cataract Refract Surg 1990;16:31-7.  Back to cited text no. 1
    
2.
Arshinoff S. Mechanics of capsulorhexis. J Cataract Refract Surg 1992;18:623-8.  Back to cited text no. 2
    
3.
Chang DF, Mamalis N, Werner L. Precision pulse capsulotomy: Preclinical safety and performance of a new capsulotomy technology. Ophthalmology 2016;123:255-64.  Back to cited text no. 3
    
4.
Chang DF. Zepto precision pulse capsulotomy: A new automated and disposable capsulotomy technology. Indian J Ophthalmol 2017;65:1411-4.  Back to cited text no. 4
[PUBMED]  [Full text]  
5.
Waltz K, Thompson VM, Quesada G. Precision pulse capsulotomy: Initial clinical experience in simple and challenging cataract surgery cases. J Cataract Refract Surg 2017;43:606-14.  Back to cited text no. 5
    
6.
Thompson VM, Berdahl JP, Solano JM, Chang DF. Comparison of manual, femtosecond laser, and precision pulse capsulotomy edge tear strength in paired human cadaver eyes. Ophthalmology 2016;123:265-74.  Back to cited text no. 6
    
7.
Hooshmand J, Abell RG, Allen P, Vote BJ. Thermal capsulotomy: Initial clinical experience, intraoperative performance, safety, and early postoperative outcomes of precision pulse capsulotomy technology. J Cataract Refract Surg 2018;44:355-61.  Back to cited text no. 7
    
8.
Hooshmand J, Abell RG, Goemann K, Davies PE, Vote BJ. Ultrastructural integrity of human capsulotomies created by a thermal device. Ophthalmology 2018;125:340-4.  Back to cited text no. 8
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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