Comparison of the Outcomes of Implantable Collamer Lens Surgery Performed by Fellows and Consultants in a Tertiary Eye Care Hospital

Abstract

Purpose

To compare the long-term outcomes and complication rates of implantable collamer lens (ICL) surgeries performed by fellows-in-training and consultant surgeons at a tertiary eye care hospital.

Patients and Methods

This was a retrospective cohort study. A chart review was performed for all patients who underwent ICL surgery for myopia and compound myopic astigmatism between January 2015 and December 2018 at King Khaled Eye Specialist Hospital and Reseach center, Riyadh, Saudi Arabia. Patients who underwent ICL implantation for hyperopia, keratoconus, or post-keratoplasty were excluded from the study. The outcomes and complication rates were compared based on whether the primary surgeon was a fellow (fellow group) or a consultant surgeon (consultant group). The primary outcome measure was the development of cataracts or endothelial cell loss, and the secondary outcome measure was visual acuity at each postoperative visit.

Results

A total of 182 eyes (114 patients) underwent ICL surgery for myopia. Mean spherical equivalent was −9.74±3.51 D for the fellow group and −9.96 ± 3.77 D for the consultant group. A toric ICL was placed in 73 (86.9%) and 80 eyes(83.6%) in the fellow and consultant groups, respectively. The median postoperative follow-up (interquartile range) for patients operated on by fellows and consultants was 31.50 (32) months and 28 (33) months, respectively. There was no statistical difference in the median change in endothelial cell count (ECC) between the groups (p = 0.812). Postoperatively, cataract developed in six eyes during follow-up; two were ICL-related. The mean LogMAR uncorrected distance visual acuity was 0.11 ± 0.14(20/25) and 0.11 ± 0.16(20/25) in the fellow and consultant groups, respectively. Visual acuity outcomes and complication rates were comparable between groups.

Conclusion

ICL implantation provided good refractive outcomes and long-term stability. There were no significant differences in postoperative ECC loss, cataract development, or other complications according to different levels of surgical experience.

Introduction

Implantable collamer lenses (ICL; Staar Surgical, Monrovia, CA, USA) have become increasingly popular among surgeons and patients as a safe and effective long-term procedure for correcting various refractive errors. In patients with high myopia, ICL improve vision and quality of life by reducing or eliminating the dependence on spectacles or contact lenses. The advantages of ICL implantation over keratorefractive surgery include a wider range of treatable ametropias, faster visual recovery, more stable refraction, and improved visual quality.¹ In cases of high myopia (≥ −8 diopters), using a phakic intraocular lens can lead to improved visual outcomes compared to keratorefractive procedures, while also offering greater safety than refractive lens exchange.² A comprehensive review examining complications in 2592 eyes following ICL implantation identified cataract formation as the primary postoperative complication, occurring in 5.2% of cases. Among these cataract cases, 15.4% were attributed to surgical trauma, while 33.8% of affected eyes demonstrated inadequate vault measurements (less than 200 μm). Regarding endothelial cell loss, the rates decreased over time from 9.9% at the 2-year follow-up to 3.7% at 4 years postoperatively.³ Cataract formation after ICL implantation is likely due to direct contact between the ICL and the crystalline lens or due to lens touch during surgical manipulation. A previous study from Saudi Arabia reported that the rate of explantation was highest in the first 2 years of the introduction of the ICL at a tertiary eye hospital. This observation suggests that a surgical learning curve effect may exist.⁴ The learning curve has been studied in ophthalmology in many surgical instances. Melles et al⁵ found no correlation in DMEK surgery between the learning curve and clinical outcomes such as best-corrected visual acuity (BCVA) and endothelial cell density. However, there were clear learning curve effects associated with the use of femtosecond lasers for cataract surgery.⁶ Adjustment to surgical technique and prior experience with a femtosecond laser seemed to flatten the learning curve.⁶ The importance of measuring the surgical learning curve has potential benefits for patient safety and surgical education.⁷ However, few studies have directly examined whether a learning curve exists in ICL implantation surgery. The aim of this study is to compare the long-term visual and safety outcomes of ICL V4c implantation performed by consultants and fellows-in-training. Specifically, the study evaluates postoperative cataract formation, endothelial cell loss, and visual acuity to determine whether surgical experience influences these outcomes.

Material and Methods

The Institutional Review Board of King Khaled Eye Specialist Hospital and Research Center (KKESH&RC), Riyadh, Saudi Arabia, approved this study (IRB Protocol number: PR 2034). The study was conducted in accordance with the principles of the Declaration of Helsinki. Written informed consent for the surgical procedure was obtained from all patients prior to surgery. However, the requirement for informed consent for participation in this retrospective study was waived by the Institutional Review Board. All patient data were anonymized and handled confidentially, with no identifiable information disclosed.

Patients

This retrospective cohort study evaluated patients who underwent ICL surgery for myopia and compound myopic astigmatism between January 2015 and December 2018 at KKESH&RC, Riyadh, Saudi Arabia. Patients who received an ICL for hyperopia, keratoconus, post-keratoplasty ametropia, and those under 18 or over 40 years of age at the time of the procedure were excluded. Data were divided based on whether the patient had undergone surgery by a fellow physician (fellow group) or a consultant surgeon (consultant group). A chart review was performed to collect data.

Preoperative Evaluation

All patients underwent a comprehensive medical and ophthalmic history assessment along with a complete ophthalmologic evaluation. This included measurements of the best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA), manifest and cycloplegic refraction, corneal topography, intraocular pressure, slit-lamp examination of the anterior segment, dilated fundus examination, and endothelial cell count (ECC). The criteria for selecting patients for ICL surgery for myopia included being at least 18 years old, having stable refraction for a minimum of 1 year prior to surgery, an anterior chamber depth of ≥2.8 mm, an ECC of ≥2500, and no signs of keratoconus. Patients wearing soft or hard contact lenses were advised to stop wearing the lenses for at least 7 and 30 days, respectively.

Fellowship Training

The fellows enrolled in the fellowship program at KKESH were board-certified and had performed >120 intraocular surgeries during their residency before starting the fellowship program. The fellows were required to perform a minimum of 25 ICL surgeries under the direct supervision of a consultant surgeon to meet the surgical requirements of the anterior segment fellowship curriculum.

Lens Power Calculation

ICL power was calculated using an online tool provided by the manufacturer, with all eyes aimed for emmetropia. Following the manufacturer’s guidelines, the suitable ICL size was chosen based on the anterior chamber depth (ACD) and the white-to-white (WTW) corneal diameter. A toric ICL was indicated to address both spherical and cylindrical refractive errors. WTW was measured by the consultant surgeon in all cases.

Operative Details

The surgical procedure for ICL implantation was performed by a consultant surgeon or a fellow under direct supervision of a consultant surgeon. For toric ICL cases, after the instillation of a topical anesthetic, the surgeon marked the horizontal axis with the patient sitting upright to account for any potential cyclotorsion when the patient was positioned supine. Preoperatively, the eyes were prepared in a sterile manner, and a topical anesthetic was applied. A small incision (approximately 3.2 mm) was made at the corneal periphery, and a cohesive viscoelastic substance was injected to maintain the anterior chamber. The folded ICL was then inserted through the incision using a specialized injector and carefully positioned behind the iris. Toric ICLs were aligned along the desired axis. After removing the viscoelastic material, the incision typically closed without suturing. Cohesive viscoelastic substances were used in all cases; however, irrigation details were not consistently documented in the operative notes. Surgical time was measured from incision to wound closure.

Postoperative Evaluation

Patients were typically evaluated 2 hours postoperatively to measure intraocular pressure (IOP) and on postoperative day 1, week 2, and months 1, 3, 6, and 12. The consultant determined whether the follow-up duration exceeded 1 year. The patients underwent measurements of visual acuity, IOP, slit-lamp examination, anterior segment optical coherence tomography (AS-OCT), and ECC.

Data Collection

A data collection sheet was used to collect data on patient demographics, preoperative visual acuity, IOP, subjective refraction, ECC, ACD, and WTW measurements. Operative data were collected at the primary surgeon level, including time of surgery and complications. Postoperative data were collected at 2 weeks, 1 month, 3 months, and 6 months, and at the final follow-up.

Outcome Measures

The primary outcome measure was the difference in the percentage of eyes that developed cataracts or experienced significant endothelial cell loss between groups. The secondary outcome was the difference in the proportions of BSCVA grades between both groups at different follow-up visits.

Statistical Analysis

Data were entered into Excel 2010 (Microsoft Corporation, Redmond, Washington, USA) and analyzed using STATA 18.0 (StataCorp LLC, College Station, TX, USA). Categorical data were presented as counts and percentages, and continuous data were presented as means with standard deviation or medians with interquartile range (IQR), depending on the normality of the data. A scatter plot was constructed to visualize the relationship between the age at surgery and endothelial cell loss after ICL implantation. A line graph was used to compare IOP trends between the groups at various postoperative intervals.

Categorical variables were compared between groups using the chi-square test or Fisher’s exact test, as appropriate. For continuous variables, the Student’s t-test was used for normally distributed data, and the Mann–Whitney U-test was used for non-normally distributed data. Statistical significance was set at p<0.05.

Results

A total of 182 eyes from 114 patients underwent ICL surgery for myopia. The study population comprised 68 females (59.6%). A toric ICL was implanted in 73(86.9%) and 80eyes (83.6%) in the fellow and consultant surgeon groups, respectively.

Age of Patients

Patients operated on by consultant surgeons had a mean age of 27.15 years (SD 5.03), with a median of 25.78 years and an IQR of 6.77; (20-40) years. In comparison, patients treated by fellows had a mean age of 28.45 years (SD 5.23), median age of 27.90 years, and an IQR of 8.74 (18 - 39) years. The difference in age distribution between the two groups was not statistically significant (Mann–Whitney U-test, p = 0.078).

Preoperative Comparisons

There were no significant intergroup differences in patient age, sex, preoperative spherical equivalent, mean cylinder size, ECC, WTW, or ACD (Table 1). Preoperative visual acuity was similar, with 60.7% of patients in the fellow group and 67.3% in the consultant group having 20/20 or better vision.

Table 1.

Demographics and Preoperative Data of Patients Undergoing Implantable Collamer Lens Implantation by Fellows and Consultant Surgeons

		Surgeon				P
		Fellow		Consultant
		Count	%	Count	%
Sex	Male	19	34.5	27	45.8	0.223
	Female	36	65.5	32	54.2
Eye	OD	40	47.6	52	53.1	0.464
	OS	44	52.4	46	46.9
Best-corrected visual acuity	20/20	51	60.7	66	67.3	0.352
	20/25	33	39.3	32	32.7
Spherical equivalent	Low myopia (−0.25 to −5.9)	4	4.8	12	12.2	0.105
	Moderate myopia (−6.0 to −9.5)	49	58.3	45	45.9
	High myopia (>-9.5)	31	36.9	41	41.8
	Mean ±standard deviation	−9.74 ± 3.51		−9.96 ± 3.77		0.680
Cylinder	Mean ±standard deviation	−1.86 ± 1.15		−1.78±1.39		0.678
Endothelial cell count	<2500	13	17.8	14	18.4	0.923
	≥ 2500	60	82.2	62	81.6
	Mean±standard deviation	2845.16± 327.88		2821.91± 308.62		0.656
Tool used to measure white-to-white distance, mm	Caliper	78	92.9	90	91.8	0.823
	Orbscan	2	2.4	4	4.1
	Tomey	1	1.2	0	0.0
	Pentacam	3	3.6	4	4.1
Anterior chamber depth, mm	≤ 2.79	0	0.0	1	1.0	>0.999
	≥ 2.80	84	100.0	97	99.0
	Mean±standard deviation	3.20±0.22		3.28±0.26		0.042

Abbreviations: OD, oculus dexter (right eye); OS, oculus sinister (left eye).

Surgical Time and Complications

The median surgical time was significantly longer for procedures performed by fellows than for those performed by consultants (20 min [IQR, 5] vs 12 min [IQR, 6], respectively; p < 0.001). No intraoperative complications occurred in either group.

Postoperative Comparisons

The mean duration of follow-up was 31.35 ± 15.87 months in the fellow group and 30.73 ± 16.27 months in the consultant group (p = 0.799). The mean IOP on postoperative day 1 was higher in fellow-operated eyes than in consultant-operated eyes (15.7 mmHg [95% CI, 14.9 to 16.5] vs 14.3 mmHg [95% CI, 13.6 to 15.0]). The mean difference was 1.4 mmHg [95% CI, 0.3 to 2.5], p = 0.013. The mean IOP did not differ significantly between the two groups at any other time point (2 hours postoperatively, p = 0.992; weeks 2–4, p = 0.816; month 3, p = 0.488; month 6, p = 0.989; last follow-up, p = 0.237) (Figure 1). Mild corneal edema was documented in four (4.8%) patients in the fellow group and in one patient in the consultant group. Wound leakage was present in two patients in the fellow group on postoperative day 1 and was managed with a bandage contact lens, which was removed the following day. No significant differences were noted in the risk of corneal edema or wound leakage on day 1 between the groups. The mean ECC decreased from baseline to the last follow-up by 7.17% (95% CI, −9.58 to −4.76; n = 58) in fellow-operated eyes and by 5.68% (95% CI, −7.40 to −3.96; n = 58) in consultant-operated eyes; the mean difference was −1.49% points (95% CI, −4.42 to 1.44; p = 0.316). Age at surgery was not significantly associated with percentage change in ECC in either group (fellow: R² = 0.03, p =0.183; consultant: R² < 0.01, p = 0.935) (Figure 2). No significant difference was noted in the median percentage change in ECC between the groups (p = 0.812). The median (IQR) percent decrease in ECC from baseline to the last follow-up was 3.97 (7) in the fellow group compared with 3.79 (4) in the consultant group.

Figure 1.

Comparison of mean intraocular pressure over time in patients who underwent implantable collamer lens implantation by fellow or consultant surgeons.

Figure 2.

Relationship between age at surgery and endothelial cell loss after implantable collamer lens implantation by fellow and consultant surgeons. ECC, endothelial cell count.

Both groups demonstrated notable improvement in uncorrected visual acuity over time, with similar final outcomes observed between the fellows and consultants (Table 2 and Table 3).

Table 2.

Uncorrected Visual Acuity on Day 1 and at the Last follow up in Patients Who Underwent Collamer Lens Implantation by a Fellow or Consultant Surgeon

Surgeon	VA, LogMAR
		Day 1				Last Follow-Up
	n	Mean	SD	Median	IQR	Mean	SD	Median	IQR
Fellow	78	0.28	0.23	0.18	0.38	0.11	0.14	0.05	0.18
Consultant	89	0.30	0.28	0.18	0.30	0.11	0.16	0.10	0.18

Abbreviations: LogMAR, logarithm of the minimal angle of resolution; SD, standard deviation; IQR, interquartile range; VA, visual acuity.

Table 3.

Uncorrected Visual Acuity on Day 1 and at the Last Follow-Up in Patients Who Underwent Toric Implantable Collamer Lens Implantation by a Fellow or Consultant Surgeon

Surgeon	VA, LogMAR	Day 1				LFU
	n	Mean	SD	Median	IQR	Mean	SD	Median	IQR
Fellow	68	0.29	0.24	0.18	0.38	0.12	0.14	0.10	0.18
Consultant	73	0.30	0.29	0.18	0.38	0.12	0.16	0.10	0.18

Abbreviations: LogMAR, logarithm of the minimal angle of resolution; SD, standard deviation; IQR, interquartile range; LFU, last follow-up.

Quantitative AS-OCT vault measurements were not consistently recorded during the study period; therefore, only subjective slit-lamp vault grades (low/normal/high) at the last follow-up were available. Low vault was observed in 22.2% of eyes operated on by fellows (18/81) and 10.3% of eyes operated on by consultants (10/97), whereas normal vault was observed in 71.6% vs 84.5% and high vault in 6.2% vs 5.2%, respectively (p = 0.082). There was no evidence of a statistically significant correlation between subjective vault grade and percentage change in ECC in either the consultant-operated subgroup (ρ = 0.088, p = 0.513, n = 58) or the fellow-operated subgroup (ρ = −0.219, p = 0.108, n = 55).

Table 4 summarizes postoperative adverse events after ICL implantation. Among the six patients who developed cataracts after ICL implantation, only two cases were identified as being directly related to the ICL procedure (Table 5). ICL-attributable cataract occurred in 2 of the 84 fellow-operated eyes (2.4%) and in none of the consultant-operated eyes (0/98). The risk difference was 2.4% points (95% CI −1.7 to 8.3, p = 0.209). Notably, the two patients with ICL-related cataracts were older at the time of surgery (37 years and 39.5 years) and one of the patients had low vault, which could be a contributing factor for cataract formation. Furthermore, Most patients had high spherical equivalent values, with one exception (Case 5, −3.87). Six patients underwent secondary procedures. One eye underwent ICL rotation and was adjusted to the correct axis in each group, and one eye underwent ICL repositioning due to trauma in the consultant group. One patient in the fellow group had an ICL exchange due to a high vault. One patient in the fellow group underwent ICL explantation for blunt trauma and cataract surgery performed by a consultant.

Table 4.

Adverse Events Following Implantable Collamer Lens Surgery Performed by Fellow and Consultant Surgeons

Complication/Secondary Procedure		Surgeon				p
		Fellow		Consultant
		Freq	%	Freq	%
Cataract*	Yes	3	3.6	3	3.1	>0.999
	No	81	96.4	95	96.9
Glaucoma	Yes	3	3.6	1	1.0	0.336
	No	81	96.4	97	99.0
Secondary procedure	No secondary procedure	81	96.4	95	96.9	0.814
	Cataract surgery	0	0.0	1	1.0
	ICL rotation	1	1.2	1	1.0
	ICL repositioning	0	0.0	1	1.0
	ICL explantation	1	1.2	0	0.0
	ICL exchange	1	1.2	0	0.0

Notes: *Two of the 6 cataracts were ICL-related. Statistical significance was set at P <0.05.

Abbreviation: ICL, implantable collamer lens.

Table 5.

Characteristics of Six Eyes (Five Patients) Who Developed Cataracts During Follow-Up After Implantable Collamer Lens Implantation

No.	Age, Years at Time of Surgery	Eye	BCVA, Preop	Surgeon	Duration of Surgery, Minutes	Vault Subjective, LFU	AS-OCT, LFU, mm	Cataract Type	SE, preop	UCVA, LFU	Surgery to Last Follow-Up Duration, Months
1	36	OS	20/20	Consultant	10	Normal	Normal	PSC, Post-thyroidectomy plus radiation	−8.12	20/40	48
2	36	OD	20/20	Consultant	13	Normal	Normal	PSC, Post-thyroidectomy plus radiation	−9.37	20/40	48
3	37	OS	20/20	Fellow	26	Normal	Not available	Faint ASC 6 months postop	−12.37	20/30	15
4	22	OS	20/25	Fellow	14	Normal	Not available	Blunt trauma 2 years after ICL; underwent ICL repositioning	−15.87	20/50	58
5	39.5	OS	20/25	Fellow	15	Low	Low	Low vault faint lens opacity, 2 years postop	−3.87	20/25	48
6	40	OD	20/20	Consultant	9	Normal	Not available	PSC, had barrage laser for retinal holes 2 years post op	−9.5	20/25	60

Abbreviations: SE, spherical equivalent; ICL, implantable collamer lens; BCVA, best-corrected visual acuity; UCVA, uncorrected visual acuity; AS-OCT, anterior segment optical coherence tomography; PSC, posterior subcapsular cataract; OD, oculus dexter (right eye); OS, oculus sinister (left eye); LFU, last follow-up. Bolded rows indicate ICL-attributable cataracts.

Discussion

In this study, fellows-in-training achieved outcomes that were statistically comparable to those of consultant surgeons given that both patient groups were comparable in terms of preoperative data. Both groups had comparable visual outcomes and complication rates. In addition, operative time was longer for fellow-performed than consultant-performed procedures (median, 20 vs 12 min; p<0.001), consistent with a learning-curve effect. Evaluation of the surgical learning curve has potential benefits for patient safety and surgical education. There are two main types of variables: measuring the surgical process and the clinical outcome.⁷ surgical literature suggests that complication rates are inversely associated with surgical volume.⁸ This suggests a short learning curve for ICL implantation if surgeons are already performing intraocular surgery. Loss of endothelial cell density (ECD) after ICL implantation remains a common concern. The effect of ICL implantation on ECD has been previously evaluated.^9–11 Edelhauser et al¹¹ demonstrated that the cumulative ECD loss ranged from 8.4% to 8.9% over the first 3 years, and from 8.4% to 9.5% over the first 4 years, depending on the calculation method used. In contrast, Goukon et al⁹ reported that the endothelial cell loss rates in eyes that received an ICL with a central hole and a conventional ICL were 0.3% and 1.1%, respectively, at 2 years postoperatively. ECD following ICL implantation for high myopia compared to low myopia has been previously evaluated with no significant loss of ECD greater than 30% at 1 year follow-up.¹⁰ We found no significant difference in the median percent change in ECC between groups (p = 0.812). The median (IQR) percent decrease in ECC from baseline to the last follow-up for eyes operated on by fellows was 3.97 (7), compared to 3.79 (4) for eyes operated on by consultants.

Several factors have been reported to be associated with postoperative endothelial cell loss. Zhang et al¹² studied the effect of irrigation and aspiration (I/A) on ECD after ICL surgery and reported a slight postoperative reduction in ECD compared with conventional irrigation using balanced salt solution. Edelhauser et al¹¹ suggested that surgical manipulation can affect ECD and that the cornea undergoes a prolonged period of endothelial remodeling. This remodeling process is reflected in ECD changes following surgical trauma. In the current study, the method of viscoelastic removal, bottle height, and fluid volume were not consistently documented in the operative notes, representing a limitation of retrospective data collection. However, the surgical manipulation parameters available for analysis did not appear to significantly influence postoperative ECD change.

Cataract formation is another potential complication following ICL implantation.¹³ Several factors have been associated with cataract development following ICL surgery. Patient-related factors, including high myopia and advanced age at the time of surgery, may predispose patients to postoperative cataract formation.^14,15 Surgical factors also play a role in postoperative cataract development. The surgeon’s experience can significantly impact the amount of manipulation and surgical trauma encountered during the ICL procedure. Sánchez-Galean et al¹⁶, reported that lens opacities developed in the early postoperative period, likely due to surgically-induced trauma. They found that most of the opacity cases occurred during the first or second ICL implantation procedure performed by surgeons who had recently begun performing the ICL implantation. They also observed a learning curve effect, with lens opacities occurring more frequently during the early surgical experience period. In their study, the incidence of lens opacities decreased from 19% in the first 16 cases to 0% in the subsequent 43 cases performed by the same surgeon. In the present study, two patients developed late-onset cataracts after ICL implantation for myopia, despite no history of postoperative trauma or medication use (Table 5). Both patients were older at the time of surgery, and their procedures were performed by fellows. Because of the retrospective study design, it was not possible to determine whether these were among the fellows’ initial cases. The irrigation method was not specified, and all patients in this series received miotic agents. These findings suggest that multiple factors may have contributed to cataract development. Vault is a key parameter after V4c ICL implantation and has been proposed to influence both cataract development and endothelial cell loss through changes in postoperative anterior segment configuration. Prior clinical evidence suggests that inadequate, particularly low, vault is associated with higher rates of postoperative cataract, and observational studies have also linked -high vault with greater endothelial cell loss.^17,18 In our study, postoperative vault was assessed using categorical slit-lamp grading rather than standardized quantitative imaging. There was no evidence of a statistically significant correlation between subjective vault category and percentage change in ECD in either the consultant-operated subgroup (ρ = 0.088, p = 0.513, n = 58) or the fellow-operated subgroup (ρ = −0.219, p = 0.108, n = 55). Therefore, within the constraints of categorical vault assessment, no detectable relationship was found between vault status and endothelial cell loss.

Toric ICL implantation has been reported to be safe and effective for patients with myopic astigmatism. Moshirfar et al¹⁹ reported that 13% of patients who underwent toric ICL implantation required additional enhancement procedures, and 1 patient required ICL repositioning. In the current study, fellows achieved final visual outcomes comparable to those of consultants in toric ICL cases. One patient in each group had ICL rotation that required readjustment to the correct axis. These results suggest that toric ICLs are a viable option for surgeons at an early stage of the learning curve. Nevertheless, meticulous patient selection is essential, and patients with risk factors for postoperative cataract development should be counseled appropriately regarding the potential for lens opacification and subsequent intervention.

This study had several limitations. Due to the retrospective design, a priori sample size calculation was not performed. Instead, the study included all eligible cases available within the predefined study period. Consequently, the sample size was determined by the number of cases meeting the inclusion criteria during the study window, which may have limited the statistical power to detect small or moderate associations. In addition, fellow training level was not documented in the operative notes, and individual cases could not be reliably attributed to specific fellows; therefore, analyses could not be stratified by fellow training stage. This may have introduced heterogeneity into the fellow cohort and limited the interpretability of subgroup comparisons. Intraoperative parameters, such as irrigation method and fluid volume, were not evaluated, although they may have contributed to endothelial cell loss and cataract formation. Additionally, the ICL loading process was not evaluated, which is relevant because the hydrophilic material of the lens is susceptible to damage during handling. This is particularly important for toric ICL implantation, in which accurate axis alignment is critical for optimal visual outcomes. Furthermore, haptic tucking beneath the iris was not assessed. This maneuver may induce mechanical stress on the crystalline lens; however, the longer surgical time observed in fellow-performed procedures suggests that this step may require additional time and technical skill. Quantitative AS-OCT vault measurements were not consistently recorded throughout the study period. Therefore, reliance on categorical slit-lamp vault assessment may have reduced measurement precision and limited the ability to detect small postoperative vault differences. Surgical simulations have demonstrated benefits for residents performing phacoemulsification.²⁰ However, for ICL procedures, structured wet-lab training focused on procedure-specific steps may be beneficial. Such training could include determining the appropriate amount of viscoelastic agent required, safely creating the incision without excessive pressure on the globe, tucking the haptics beneath the iris with minimal manipulation, and optimizing irrigation bottle height for viscoelastic removal without inducing lens changes. Additionally, learning techniques for managing ICL flipping is particularly important for novice surgeons, as this may significantly reduce surgical time, especially for procedures performed under topical anesthesia. Careful patient selection remains essential for ICL implantation, and long-term annual follow-up may be necessary to monitor postoperative procedural safety.

Conclusion

In conclusion, Visian ICL V4c implantation for correction of myopia and compound myopic astigmatism appears safe and effective, providing stable visual and refractive outcomes with low adverse event rates across levels of surgeon experience. In this cohort, outcomes after procedures performed by fellows and consultants were comparable; however, fellow-performed procedures were supervised, and the safety profile observed here may not be directly generalizable to unsupervised early-career surgeons. The incidence of cataract was low and may have been influenced by careful patient selection and continued refinement of preoperative assessment parameters.

Funding Statement

The authors received no financial support for the research, authorship, and/or publication of this article.

Data Sharing Statement

Data supporting the results in this manuscript are available from the corresponding author on reasonable request, subject to applicable ethical and privacy restrictions.

Disclosure

The authors report no conflicts of interest in this work.