Safety and Suitability of Implantable Collamer Lens (ICL) Implantation for Correction of Refractive Errors Without the Use of Dispersive Ophthalmic Viscosurgical Devices (OVDs)
Conditions: Refractive Errors, Myopia, Myopic Astigmatism, Hypermetropia
Sponsor: Loay Abdulmutalib Almusawi

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Study Protocol and Statistical Analysis Plan 
Study title: 
Safety and Suitability of Implantable Collamer Lens (ICL) Implantation 
for Correction of Refractive Errors Without the Use of Dispersive 
Ophthalmic Viscosurgical Devices (OVDs) 
Principal Investigator:  
Sohaib Ahmed Mahmood, MD 
Practicing ophthalmologist 
Ibn Al-Haithem teaching eye hospital 
 
Co-investigators:  
 
Loay Abdulmutalib Almusawi, MD 
Lecturer 
College of Medicine, University of Basrah 
 
Sarah Alhussein, MD 
Basrah health directorate 
 
 
 
 
 
 
Protocol Version Number and date: 
Draft 2.0  
20/10/2023 
 
Sponsor: Loay Abdulmutalib Almusawi, MD 
Lecturer 
College of Medicine, University of Basrah 
 
Ethics Committee Reference:  
 
Board Name: Scientific and Ethical Committee 
 
Approval number: 030409-004-2024 
Board Affiliation: College of Medicine, University of Basrah 
Phone:   Email: medical.college@uobasrah.edu.iq 
 

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List of Abbreviations 
BSS: Balanced Salts Solution 
CV: Coefficient of Variation 
ECD: Endothelial cells density 
ICL: Implantable Collamer Lens 
IOP: Intra-Ocular Pressure 
OVD: Ophthalmic Viscosurgical Device 
PIOL: Phakic Intra-Ocular Lens 
 
 

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Table of Contents 
1. Background ..................................................................................................................... 4 
2. Aim (objective) ............................................................................................................... 4 
3. Study Design and Methodology .................................................................................... 4 
3.1 Study overview ...................................................................................................................................................... 4 
3.2 Study setting/location ........................................................................................................................................ 4 
3.3 Study population .................................................................................................................................................. 4 
Eligibility criteria .................................................................................................................................................... 4 
3.4 Identification and recruitment of participants ........................................................................................ 5 
3.5 Study interventions / procedures ................................................................................................................. 5 
3.6 Data collection and analysis ............................................................................................................................. 5 
3.7 Handling of missing data ................................................................................................................................... 6 
4. Statistical Considerations ............................................................................................... 6 
4.1 Sample size and statistical power .................................................................................................................. 6 
4.2 Statistical methods ............................................................................................................................................... 6 
5. Ethical Considerations .................................................................................................... 6 
6. Study impact and significance...................................................................................... 7 
7. References ...................................................................................................................... 7 
 
 
 
 

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1 Background 
Refractive errors (myopia, hyperopia and astigmatism) are quite prevalent worldwide, they 
constitute the most common cause of visual impairment with myopia in particular being 
progressively increasing in its prevalence so that it is predicted that by 2050 nearly half of 
the world population will be myopic.1,2 Management modalities include correction with 
glasses, contact lenses, laser vision correction, intracorneal implants and intraocular 
refractive procedures such as phakic intraocular lens (PIOL) implantation which involves 
the use of implantable collamer lens (ICL) in many cases.3 PIOLs are being extensively used 
since they preserve the integrity of the cornea and thereby attaining higher quality of vision 
compared with conventional kerato-refractive procedures. Furthermore; they allow 
broader range of refractive errors to be corrected.3,4 The Staar V4c EVO visian ICL (Staar 
surgical Inc, Lake Forest, CA, USA) has demonstrated effectiveness and an excellent safety 
profile with more than one million ICL implants had already been performed globally.4 
However, complications such as raised intraocular pressure (IOP), cataract and pupillary 
block do happen.4,5 The ICL implantation procedure typically utilizes viscoelastics to 
facilitate introduction and positioning of the implant. Viscoelastics should be removed 
thoroughly at the conclusion of the procedure, and failure to do so may induce early 
postoperative IOP rise.6,7 It is logical to assume that viscoelastics use during surgery 
increases operation cost and time due to the extra steps involving the injection and 
removal of the substance. Increased manipulation during ICL implantation surgery and 
irrigation required to ensure adequate removal of viscoelastics may encourage cataract 
formation as well.5 Few studies investigated the safety and efficacy of ICL implantation 
without the use of viscoelastics, where they implemented balanced salt solution (BSS) 
instead as a novel technique8,9. In the present study we retrospectively investigated the 
safety and efficacy of modifying ICL implantation technique by using cohesive OVD only 
without using dispersive OVDs.  
 
2 Aim(s) / Objective (s) 
Is omitting dispersive viscoelastic from the standard surgical technique and utilizing only 
cohesive OVDs (in what we call it reduced- OVD technique) safe and suitable? 
3 Study Design and Methodology 
3.1 Study Overview 
This is a retrospective cross-sectional comparative study.  
Data from private hospital records were accessed and analysed retrospectively. 
3.2 Study Setting / Location 
The study participants were all from Al-Ferdos private hospital in Baghdad, Iraq. 
3.3 Study Population 
All refractive surgery candidates attending the above hospital for the purpose of phakic 
introcular lens implantation were included in the study.  However, the initial group allocation 
occurred before the commencement of the study on the basis of surgeon and patient preference, 
thereby, randomization was on convenient basis.  
3.3.1.1 Eligibility Criteria 
To be eligible for enrolment into the study all of the inclusion criteria must be met. A participant 
will be excluded from the study if any of the exclusion criteria is present. 

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Inclusion Criteria 
Refractive surgery candidates 
Aged from 18-55 years 
Phakic intraocular lens implantation was performed (ICL type) 
Committing to at least one preoperative visit for baseline assessment and multiple 
postoperative visits (at least 2 visits within a year) for follow-up assessment. 
Exclusion Criteria 
Patients with incomplete data and no commitment to follow up visits 
Presence of the following ocular conditions preoperatively: unstable refraction, severe ocular 
surface disease, cataract, glaucoma, corneal pathology such as Fuch’s dystrophy or corneal 
scarring, uncontrolled intraocular inflammation, macular scarring or any other retinal issue that 
may adversely affect vision after surgery. 
 
3.4 Identification and Recruitment of Participants 
Potential participants will be identified by screening of all medical records from the above 
hospital regardless of the time of the surgery. 
Study investigators will identify study participants individually after screening of medical 
records. 
Since this study is retrospective, initial surgery consent was considered as the participant 
consent for the study. 
3.5 Study Interventions / Procedures 
After enrolment, the record of each participant is examined meticulously for completeness of 
preoperative and postoperative data pertaining to study including: 
Patient age and gender, date of the procedure and its operative notes including laterality and 
surgical steps. 
preoperative and postoperative assessments such as uncorrected and best corrected visual 
acuity, refractive error quantification both objectively utilizing an autorefractometer 
autorefractor Nidek ARK 1 (Nidek Inc, Gamagori, Japan) and subjectively as manifest refraction, 
clinical slit-lamp examination notes, intraocular pressure with air puff tonometers, AC depth 
assessment by Pentacam Scheimpflug (Oculus Optikgeräte GmbH Inc., Wetzlar, Germany), 
specular microscopy study of corneal endothelial cells (endothelial cell density (ECD), 
coefficient of variation (CV) and hexagonality) using Topcon SP-1p Specular Microscope 
(Topcon Corporation, Tokyo, Japan), 
Typically, there is a preoperative visit and multiple postoperative visits extending over the 
period of 1-2 years after the procedure. 
3.6 Data collection and analysis 
Data will be collected by study co-investigators with assistance from IT personnel at the 
respective hospital from patients records that were identified as eligible for the study according 
to the inclusion criteria above. According to their data, participants will be split into two groups:  
1- Traditional OVD group 

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In this group of patients, the ICL was implanted utilizing both cohesive and 
dispersive ophthalmic viscosurgical device. 
2- Reduced OVD group 
In this group of patients, the ICL was implanted with the use of cohesive OVD only. 
There is one primary outcome of interest which is the unaided visual acuity after the surgery, 
and several secondary outcomes including postoperative intraocular pressure, corneal specular 
microscopy parameters (ECD, CV and hexagonality), and the observed adverse events that can 
happen during the operation or postoperatively. 
Data will then be stored electronically in a sheet format to enable for later statistical analysis. 
Data collection was started at the conduct of the study in March 2024, and it is expected to be 
completed 3-4 months later. 
3.7 Handling of Missing Data 
Section 3.5 of this protocol defines the data sets that will be collected from patients. Any missing 
information in this regard would be considered as incomplete data and this will meet an 
exclusion criterion and thereby a participant would be totally excluded from the study even if all 
other parameters are present. 
4 Statistical Considerations 
Biostatisticians had been consulted regarding the statistical analysis of data from this study. 
4.1 Sample size and statistical power 
This study involves a convenient non-probability sample based on the availability of patients 
records in the respective center for enrolment and analysis. 
4.2 Statistical methods 
After collection of data from patients records and its subjection to thorough analysis for 
incompleteness and exclusion criteria, these data will be stored electronically in sheet 
formats for later analysis. All statistical test and subsequent analyses will be performed using 
SPSS version 26 (IBM statistical software). Data will be classified into categorical and 
numerical. Categorical variables were described using frequencies and percentages and were 
analysed using Chi-squared test. Numerical variables, described as mean + standard 
deviation, will be subjected to tests of normality to determine the appropriate statistical tests 
for inter- and intra-group comparisons. Unpaired t test or Mann-Whitney test was used to 
compare the two groups (traditional and modified OVD) according to fulfilled statistical 
assumptions. These two groups were compared for statistically significant difference 
regarding all parameters that were collected as per section 3.5 of this protocol. These 
statistical comparisons were made both preoperatively to determine baseline characteristics 
of the study participants and postoperatively to determine any significant difference 
between the two groups. Within the same group whether traditional or reduced OVD, all of 
the aforementioned parameters were compared again pre- and postoperatively this time 
using either one sample paired t test or Wilcoxon signed-rank test according to fulfilled 
statistical assumptions. Significance was considered at P value less than 0.05. 
5 Ethical Considerations 
The study merely investigates the records of patients that had already undergone refractive 
surgeries. It followed the principles of the “Declaration of Helsinki” and local laws and 
regulations. 

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The study was approved by the institutional review committee at the respective hospital and a 
similar committee at the college of medicine of university of Basrah according to the local 
guidelines and protocols. Written informed consent was obtained from each patient before the 
surgery.  
Patients data are to be stored safely electronically using dedicated computers for the task. 
Patients privacy and confidentiality was taken into account. 
6 Study Impact and Significance 
Traditionally dispersive OVDs has been used extensively during loading and implantation steps 
of ICL surgery. Reducing both the amount and the types of viscoelastics used (cohesive only) 
might potentially reduce cost and time of the procedure and might provide a substitute for 
safety studies regarding omitting or further reduction of cohesive OVDs and utilizing BSS only 
which carries lower risk of raised IOP and lower cost of the procedure. 
7 References 
1- Hashemi et al. Global and regional estimates of prevalence of refractive errors: Systematic 
review and meta-analysis. Journal of Current Ophthalmology 30 (2018) 3e22. 
http://dx.doi.org/10.1016/j.joco.2017.08.009 
2- Holden et al. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 
through 2050. Ophthalmology. Volume 123, Number 5, May 2016 
http://dx.doi.org/10.1016/j.ophtha.2016.01.006 
3- American Academy of Ophthalmology. Refractive Errors & Refractive Surgery Preferred 
Practice Pattern. Clinical guideline 2017 http://dx.doi.org/10.1016/j.ophtha.2017.10.003  
4- Mark Packer. Meta-analysis and review: effectiveness, safety, and central port design of the 
intraocular collamer lens. Clinical Ophthalmology. 2016:10 1059–1077.  
5- Fernandes et al. Implantable collamer posterior chamber intraocular lenses: a review of 
potential complications. J Refract Surg. 2011 Oct;27(10):765-76. doi: 10.3928/1081597X-
20110617-01. 
6- Almalki S, Abubaker A, Alsabaani NA, Edward DP. Causes of elevated intraocular pressure 
following implantation of phakic intraocular lenses for myopia. Int Ophthalmol. 
2016;36(2):259–65.  
DOI: 10.1007/s10792-015-0112-4 
7- Senthil S, Choudhari NS, Vaddavalli PK, Murthy S, Reddy JC, Garudadri CS. Etiology and 
management of raised intraocular pressure following posterior chamber phakic intraocular lens 
implantation in myopic eyes. PLoS One. 2016;11(11):e0165469. DOI: 
10.1371/journal.pone.0165469 
8- Peng Pan et al. A novel ophthalmic viscosurgical devicefree phakic intraocular lens 
implantation makes myopic surgery safer. Eye and Vision. (2020) 7:18  
https://doi.org/10.1186/s40662-020-00185-4  
9- Peng et al. Safety of implantable Collamer lens implantation without ophthalmic viscosurgical 
device: a retrospective cohort study. Medicine. (2020) 99:24 
http://dx.doi.org/10.1097/MD.0000000000020691