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ORIGINAL ARTICLE
Year : 2023 | Volume
: 37
| Issue : 1 | Page : 15-19
To study the learning curve of capsulorhexis in manual small incision cataract surgery among postgraduate residents in central India
Rajesh S Joshi1, Nida Raza1, Preeti Wadekar1, Nivedita Patil1, Sonali Tamboli1, Tanmay Surwade1, Namrata Bansode1, Avinash Turankar2
1 Department of Ophthalmology, Government Medical College, Nagpur, Maharashtra, India
2 Department of Pharmacology, Government Medical College, Nagpur, Maharashtra, India
Correspondence Address:
Rajesh S Joshi
77, Panchatara Housing Society, Manish Nagar, Somalwada, Nagpur - 440 015, Maharashtra
India
Source of Support: None, Conflict of Interest: None
DOI: 10.4103/sjopt.sjopt_135_21
PURPOSE: To evaluate the learning curve of continuous curvilinear capsulorhexis (CCC) and to assess the number of surgeries required to master it among residents in a postgraduate teaching institute.
METHODS: The present prospective observational study was based on the completion time and complication rates related to CCC performed using various techniques by 10 students in the 2nd (JR2) and 3rd-year (JR3) of residency. CCC was performed either by a cystotome or capsulorhexis forceps or by a combined method in 253 eyes, of which 160 eyes (63.2%) were operated by JR3 and 93 (36.8%) by JR2. The complication rates were studied with respect to the number of capsular extensions, posterior capsular rent (PCR), zonular dehiscence, need for senior surgical assistance, and nucleus drop.
RESULTS: The average time required for the completion of CCC was 412 ± 90.5 s. The average number of times residents required to fill the anterior chamber with viscoelastic was 6.9 ± 1.4. The average size of CCC was 7 ± 0.66 mm. Extended CCC was the most common complication. JR2 required assistance from a senior surgeon in 47 eyes (50.5%), whereas JR3 required assistance in 39 eyes (24.4%) (P = 0.0001). The rate of PCR was not significantly different in JR2 (7.5%) and JR3 (8.8%).
CONCLUSION: CCC is a difficult step to master in the trainee. Focusing and practicing on this step will help to reduce the complications and maximize proficiency. Approximately 6–eight surgeries are required to master CCC.
Keywords: Capsulorhexis, cataract surgery, complications of cataract surgery learning in residents, learning curve
Cataract surgery is the most commonly performed eye surgery in the world. With the increasing burden of cataracts in developing countries, there is a greater need for competent ophthalmologists who can perform cataract surgery without any complications. Therefore, the trends in surgical teaching of residents are changing with efforts directed toward instituting new learning tools and early introduction of cataract surgery in the residency program.[1],[2] However, the training of residents who are registered for the postgraduate course depends on the trend that is being followed in the institute. During the 1st year in an institute, residents work under the supervision of their immediate seniors. They observe surgeries, assist their immediate seniors, familiarize themselves with basic extraocular surgeries, and perform lid and conjunctival suturing under the microscope. Cataract surgery training begins before the completion of the 1st year of residency in a step-wise manner.
Continuous curvilinear capsulorhexis (CCC) is a vital step in all types of extracapsular cataract surgeries. Performing good CCC is crucial for successful cataract surgery. With the recent technological development in cataract surgery and the emergence of premium intraocular lenses (IOLs), CCC has gained considerable importance. A well-performed CCC is crucial for the long-term stability of the IOL and visual acuity. Most studies have reported that the CCC is the difficult learning part of cataract surgery and has a learning curve.[3],[4],[5],[6],[7],[8] The various methods to train residents in cataract surgery include chart and data review,[3],[4],[9] surgical simulator,[10],[11],[12] and digital video recording.[13],[14] The complication rate associated with CCC is variable and reported between 3.1% and 6.5%.[4],[8],[15],[16] There are several issues related to CCC learning such as the extension of the rhexis and very small or large CCC. The aim of any teaching program is surgical training with minimal or no complications. The residents are usually trained in a step-wise manner either from the first to the last step[17] or in a reverse direction.[16] Most studies on the learning of cataract surgery are performed by residents who have adequate cataract surgery training[3],[4],[7],[8],[11],[15],[16],[17],[18],[19],[20] and focus on extracapsular, phacoemulsification, or femtosecond cataract surgery.[13] The present study deals with the learning curve of junior residents in the ophthalmology department of a tertiary eye care center in central India on capsulorhexis, the most vital aspect of cataract surgery. We also attempted to find out how many surgeries are required to learn the step.
MethodsAfter institutional ethics clearance and in accordance with the Declaration of Helsinki, this prospective and observational study was conducted from February 2019 to February 2020 on 10 junior residents in the 2nd year (JR2) and 3rd-year (JR3) of residency at a tertiary eye care center providing free services in central India. Of the 10 residents, three were JR3 and seven were JR2. At the start of the study, JR3 had performed a minimum of 18–20 surgeries and assisted 45–50 surgeries and JR2 had performed 12–15 surgeries and assisted 35–40 surgeries.
All patients were admitted 1 day before the surgery. The preoperative evaluation included the best-corrected visual acuity of both eyes, a thorough slit-lamp examination, intraocular pressure, retinal evaluation, and physician clearance for the surgery. Patients with a poorly dilating pupil (<5 mm); pseudoexfoliation; subluxated and complicated cataract; corneal opacity; previous ocular surgeries such as glaucoma; postvitrectomized eyes; one eye patients; patients with systemic problems such as cerebrovascular episodes, chronic obstructive airway diseases, and morbid obesity; and those not willing to participate in the study were excluded from the study.
On the day of surgery, the pupils were dilated with mydriatics (Appamide plus eye drops, Appasamy Ocular Device Private Limited, Puducherry, India). All patients were operated for cataract surgery under peribulbar anesthesia by a small incision. A fornix-based conjunctival flap was performed, and wet-field cautery was used to cauterize the bleeding vessels. A 6-mm linear scleral groove was made with the help of a No. 15 blade, and a sclerocorneal tunnel was prepared. A side port was created on the nasal side of the left eye is to be operated on, whereas it was created on the temporal side of the right eye is to be operated. The size of the side port was 0.9–2 mm depending on the preference of the resident performing the CCC. Air was injected into the anterior chamber. Trypan blue dye was injected under air to stain the anterior capsule. The anterior chamber (AC) was filled with viscoelastic (2% hydroxypropyl methylcellulose, Appavisc, Appasamy Ocular Devices, Puducherry, India). The observer noted the method used for the CCC (needle capsulotome, rhexis forceps, or combination of both), the time required for the CCC, the number of times the AC was filled with viscoelastic, CCC extension, size of CCC, and complications such as posterior capsular rent (PCR), nucleus drop, and the need for senior surgeon assistance to take over during the CCC was noted. The time required for the CCC was measured from the introduction of the cystotome or capsulorhexis forceps to the bringing out of the capsular flap from the AC. The size of the CCC was measured with the help of the Castroviejo caliper. After the completion of the CCC, caliper was placed over the cornea in a vertical and horizontal direction to measure the opening of the CCC. The average of the meridian was taken as the size of CCC. In the case of an irregular CCC, an average of three measurements in different directions was considered. The senior surgeon noted these observations either through the side-view observer scope or on the closed-circuit television. The data were entered into the pro forma after the completion of the surgery.
Statistical analysis
The data from the pro forma were entered in an Excel® sheet (Software version 14.1.0 (110310)/2011) (Microsoft Corporation, Redmond, WA, USA), and statistical analysis was performed with SPSS version 13.0 (SPSS Inc., Chicago, IL, USA). The data were described using mean ± standard deviation or number and percentage. Repeated analysis of variance test was applied for multiple comparisons and unpaired t-test was used to find any significant difference between the time difference and size of the CCC in the two groups. Fisher's exact test was used to find any significant difference between extended CCC, PCR, and senior surgeon assistance in between JR2 and JR3. Surgical assistance and the extended CCC were considered to obtain the number of surgeries required to master the step. P < 0.05 was considered statistically significant.
ResultsA total of 10 residents, three JR3 and seven JR2 were enrolled in the study and operated 253 eyes during the study period. Of the 253 eyes operated, 140 eyes (55.3%) had mature and 113 eyes (44.7%) had immature cataracts. Of these, 160 eyes (63.2%) were operated by JR3 and 93 (36.8%) by JR2. Two residents performed CCC with the help of capsulorhexis forceps, one performed with needle and capsulorhexis forceps, and seven residents performed with the needle only. The average time required for the completion of CCC is 412 ± 90.5 s (JR2 460 ± 46 s, JR3 300 ± 60 s, P = 0.03). The average number of attempts residents required to fill the AC with viscoelastic was 6.9 ± 1.4 (JR2 7.7 ± 1.3, JR3 5.3 ± 0.8). The average size of CCC was 7 ± 0.66 mm (JR2 7.4 ± 0.38 mm, JR3 6.2 ± 0.3 mm, P = 0.001). Extended CCC was the most common complication, followed by PCR. Residents who used needle had extended rhexis in 25 eyes, residents who used forceps had an extension in 20 eyes, and residents who used forceps and needle had an extension in seven eyes (P = 0.42). Details of the complications are listed in [Table 1]. JR2 required senior surgeon assistance in 47 eyes (50.5%), whereas JR3 required assistance in 39 eyes (24.4%) (P = 0.0001). The rate of PCR was not significantly different in JR2 (7.5%) and JR3 (8.8%) (P = 0.43). All 86 eyes required assistance (47 + 39). Total of 10 residents were included in the study (86/10 = 8.6). Therefore, approximately 6–8 surgeries are required to master CCC.
Table 1: Details of the complications during learning of continuous curvilinear capsulorhexis Discussion There have been studies on the transition from extracapsular cataract surgery to manual small-incision cataract surgery (MSICS) and from MSICS to phacoemulsification. Various teaching methodologies have been followed worldwide.[10],[11],[12],[13],[14] These studies have been conducted with participants having some experience in performing cataract surgeries and considerable hand-eye coordination as ophthalmic surgeries are performed under a microscope. In our study, although the participants assisted in cataract surgeries and were exposed to extraocular surgeries under an operating microscope, they were new to performing cataract surgery.
We focused on the most crucial step of cataract surgery, CCC, as it is the most challenging step for residents to master.[11] Perfecting the difficult portion of the surgery might help in building confidence for overall surgical improvement. We resorted to a teaching method that is neither the conventional start-to-finish strategy nor the full reverse way of learning cataract surgery. To get used to the hand-eye coordination and depth of focus required for the microscope, residents were exposed to simple steps of the cataract surgery such as viscoelastic removal after IOL implantation and suturing of the sclerocorneal tunnel before being included in the cohort. We termed this teaching method as the partial reverse way of teaching cataract surgery. Malavazzi et al. suggested the reverse way of teaching cataract surgery and obtained low rates of complications.[16] In the reverse way of learning, trainees perform less step-dependent procedures first such as viscoelastic clearance from the AC, cortex wash, and nucleus management, followed by IOL implantation. However, Suryawanshi et al. demonstrated that the conventional way of teaching cataract surgery is equally safe and effective.[21]
In our institute, we guide residents either through the observer scope or on the closed-circuit television. The same strategy was followed in this study. There are numerous ways to train residents. Daly et al. compared the surgical simulator and traditional wet-laboratory training for CCC in residents and discovered that both modalities were useful for teaching.[11] Bergqvist et al. demonstrated that repetitive training on the Eyesi simulator improved cataract surgery skills in medical students with no previous ophthalmic experience within a year from graduation.[22] However, simulators are expensive and not easily available. Ramani et al. performed a retrospective analysis of the effect of wet-laboratory training on the surgical outcome of MSICS performed by residents and concluded that wet-laboratory training assists in the improvement in the quality of surgery and postoperative visual outcome.[23] The disadvantage of wet-laboratory training is its maintenance and the cost involved in setting up the laboratory. Smith et al. evaluated the CCC teaching method of observing video clips and concluded that immediate error rectification by the observer is not possible in this type of teaching technology.[19]
In our institute, postgraduates are taught MSICS because it is easy to learn, is the surgery of choice in the developing world, can be performed in all cataract grades,[24],[25] and exhibits fewer complications compared with phacoemulsification cataract surgery in trainees.[26] In a large study conducted by Haripriya et al. the complication rate for trainees was significantly higher with phacoemulsification (4.8%) than with MSICS (1.46%).[26] During MSICS training, we introduce residents to the phacoemulsification steps such as performing a clear corneal incision, side port, and CCC.
Patients with comorbid ocular conditions were not allotted to the residents to ensure uniformity of the cohort. The majority of the eyes had pupillary dilatation over 5 mm and a normal or deep AC. Of the 253 eyes operated on, 140 (55.3%) had a mature and 113 (44.7%) had an immature cataract. None had intumescent cataracts. We recommended the staining of the anterior capsule with trypan blue for every case. Staining assists in the visualization of the anterior capsule during CCC. Dada et al. stressed the staining of the anterior capsule when trainees performed cataract surgery even in immature cataracts to reduce the incidence of complications.[7] The observer could make out the CCC margin and the extension to the periphery and intervene to avoid complications associated with CCC extension. Seven residents preferred to perform CCC with a needle, two residents with rhexis forceps, and one with a needle and rhexis forceps. The choice of instrumentation for CCC depends on what the residents learn from their immediate seniors and mentors. CCC extension was the most common complication observed in the study, with 36 eyes (22.5%) performed by JR3 and 16 eyes (17.2%) by JR2 displaying this complication. Dooley and O'Brien also agreed that CCC was the most difficult step to learn as a trainee.[27] Adnane et al. also studied the CCC complications in residents learning cataract surgery.[28] The same was highlighted by many authors.[3],[4]
Extended CCC was seen more (n = 25) in eyes operated by residents using the needle capsulotome compared with those using forceps (n = 20) and a combination of forceps and needle capsulotome (n = 7). Residents (n = 7) preferred to use a needle capsulotome to forceps (n = 2) and the combined approach (n = 1). It was beyond the scope of this study to investigate whether the forceps had better control than the needle capsulotome, leading to fewer extended CCCs. The average time required for the completion of CCC in JR2 (460 ± 46 s) was more than in JR3 (300 ± 60 s). The time required for performing CCC also included the adjustment of the microscope, senior surgeon assistance in case of an extended CCC, and the filling of the AC with viscoelastic. JR2 needed to fill the AC more times than JR3 (JR2 7.7 ± 1.3, JR3 5.3 ± 0.8), suggesting that experience helps to reduce the surgical time. A similar observation was made by Smith et al., in their study, on the evaluation of CCC by 3rd-and 4th-year postgraduate students and experienced surgeons from recorded videos.[19]
We also studied the size of the CCC. The size of CCC was measured by the Castroviejo caliper. However, the accurate way to measure CCC is with help of using a CCC marker. Due to the nonavailability of the marker, we have to resort to this measurement of the size of CCC. In the learning phase, we expected the size of CCC to be either on the larger or smaller side. The average size of CCC was 7 ± 0.66 mm (JR2 7.4 ± 0.38 mm, JR3 6.2 ± 0.3 mm). A large-size CCC (6–7 mm) is usually preferred in MSICS to bring the nucleus out from the capsular bag. A large-size CCC is more difficult to correct than a small size. Large-size CCC and extended CCC to the posterior capsule may lead to prolapse of vitreous in the AC and nucleus drop. A proper-sized CCC requires practice and continuous monitoring. We could not compare the CCC size in trainees learning cataract surgery, as there are no studies in the literature comparing the CCC size in residents to the best of our knowledge.
We also studied the rate of PCR as part of the study. The rate of PCR was not significantly different in JR2 (7.5%) and JR3 (8.8%). However, it was difficult to conclude whether the PCR was associated with the CCC or other steps of the cataract surgery. The PCR rate in trainees performing cataract surgery is variable and ranges from 4.9% to 10%.[2],[9],[16],[21],[23],[27],[29] The variability in the occurrence of PCR in various studies is probably due to the differing trainee experience, methods followed to assess the teaching method and stage of intervention by the supervisor.
Looking at the PCR rate in trainees, we were encouraged to start teaching cataract surgery to 1st-year junior residents (JR1) (at least till the CCC level) under supervision so as to create consistency in the training of the residents. This addresses the inadequate and inconsistent training of residents in various studies[30],[31],[32] and helps to develop cataract surgical skills in residents to tackle the backlog of cataract surgeries. Considering the number of times JR2 needed surgical assistance and the rate of extended CCC, approximately 6–8 surgeries are required to master this step. However, this is not a magic number. It could be variable in different setups with different expertise. We could not compare our results as there is no available literature on the number of cases to master CCC.
The limitation of the study was the small sample size and inclusion of residents with unequal experience. The reason for these limitations was that at any given time, there are residents who are in their early phase of residency (JR1) and residents with 2 years of experience (JR3). Hence, an equal sample would have led to a sample of 4–5 residents only.
ConclusionThus, CCC is a difficult step to master for trainees learning cataract surgery. Focusing on and practicing this step will help to reduce the complications and maximize proficiency. Approximately 6–8 surgeries are required to master the CCC.
Acknowledgment
We would like to thank Dr. Rohit Khanna, Consultant Ophthalmologist, LVP Eye Institute, Hyderabad, India, for the statistical assistance.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
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