Conditions: Thyroid Carcinoma Radioactive Iodine Level
Allocation: NA | Intervention model: SINGLE_GROUP
Enrollment: 9
Healthy volunteers: no

Brief summary:
The purpose of this study is to explore whether administration of preservative free artificial tears will decrease the level of detectable radioiodine in the tears and nasolacrimal duct system of patients undergoing radioiodine therapy for thyroid carcinoma and thus decrease the risk of developing radioactive iodine associated nasolacrimal duct obstruction.

Detailed description:
Primary Objective:

\- To assess whether use of preservative free artificial tears following radioactive iodine administration will lower the level of radioactive iodine in the tears of patients treated with radioactive iodine for thyroid carcinoma.

Secondary Objective:

\- To evaluate whether artificial tears would be an effective preventative intervention to decrease the risk of developing nasolacrimal duct stenosis, which has been associated with radioactive iodine administration.

Arms:
arm 1: Day 1, patients will self-administer artificial tears every 15 minutes for 2 hours followed by every 30 minutes for at least 4 hours or until bedtime at night. On Day 2, patients will self-administer artificial tears every 1 hour for 12 hours. On Day 3, patients will self-administer artificial tears four times that day. On Day 4, patients will self-administer tears twice that day. Patients will be instructed to wear their contact lenses throughout their waking hours.

Interventions: intervention 1: Artificial Tears
Intervention descriptions: intervention 1: Self-Administered - utilizing eye drop preservative free vials

Protocol document:
ICF_001.pdf: 


VUMC Institutional Review Board  
2 
Informed Consent Document for Research
Study Title:  
Effect of Artificial Tears on Radioiodine Levels in the Nasolacrimal Duct System of  
Patients Following Radioiodine Therapy for Thyroid Carcinoma  
Version Date:  
1/7/2022 
PI:  
Dr. Rachel Sobel  
  
This box is for 
IRB USE ONLY 
Do not edit or delete 
  
Restrictions on daily activities include cessation of any other eye drops outside the designated artificial 
tear schedule of this study.  If you wear biweekly or monthly soft contacts, you must practice early 
cessation of each contact lens so that the lenses from each day can be collected in a sterile container for 
analysis. We will reimburse you for each of the contact lenses you dispose of prior the original intended 
cessation date. For example, if you wear monthly soft contacts on both eyes, we will reimburse you for 
the cost of 8 monthly soft contacts (4 days worth of bilateral contacts). There are no other costs to you 
for taking part in this study.   
  
  
  
Detailed Information: 
The rest of this document includes detailed information about this study (in addition to the information 
listed above).  
  
You are being asked to take part in this research study because you are receiving radioactive iodine 
therapy for thyroid carcinoma and wear bilateral soft contact lenses.     
You do not have to be in this research study. You may choose not to be in this study and get other 
treatments without changing your healthcare, services, or other rights.  You can stop being in this study 
at any time.  If we learn something new that may affect the risks or benefits of this study, you will be 
told so that you can decide whether or not you still want to be in this study.   Your medical record will 
contain a note saying you are in a research study and may contain some research information about 
you.  Anyone you authorize to receive your medical record will also get this information.  
Side effects and risks that you can expect if you take part in this study:  
All side effects and risks associated with artificial tears are rare; allergic reaction, including but not 
limited to skin rash, itching or hives, swelling of the face, lips, or tongue, blurry vision, change in vision, 
minimal risk to the cornea, watery eyes, eye redness, eye itching, eye irritation, or pain. 
Risks that are not known: 
Date of IRB Approval: 03/08/2022
Date of Expiration: 03/07/2023


VUMC Institutional Review Board  
3 
Informed Consent Document for Research
Study Title:  
Effect of Artificial Tears on Radioiodine Levels in the Nasolacrimal Duct System of  
Patients Following Radioiodine Therapy for Thyroid Carcinoma  
Version Date:  
1/7/2022 
PI:  
Dr. Rachel Sobel  
  
This box is for 
IRB USE ONLY 
Do not edit or delete 
None. Preservative-free artificial tears are FDA-approved eye drops used for the treatment of dry eyes 
and can be obtained over the counter.  
  
Good effects that might result from this study:
The results of the study may provide possible a possible intervention for reducing the risk of developing 
radioactive iodine associated nasolacrimal duct stenosis.   
Procedures to be followed: 
You will be instructed to administer artificial tears into the right eye only in the following schedule:  Day 
1 (day of radioactive iodine therapy): every 15 minutes for 2 hours, then every 30 minutes for at least 4 
hours or until bedtime at night  
Day 2: once every 1 hour for 12 hours  
Day 3: four times   
Day 4: two times   
  
You must be wearing bilateral soft contact lenses at the time of radioactive iodine administration and for 
at least 12 hours a day. Contacts must be worn during artificial tear administration.   
  
Bedtime: remove RIGHT contact first, place in RIGHT lens case. Rinse your hands, pat dry. Then remove 
left contact, place in LEFT lens case. 
  
Store contacts in different lens case every night before going to sleep. Put a whole vial of GenTeal 
artificial tears to cover the contact lens in the case. One vial of tears for the right, and one vial of tears for 
the left. 
Day of Imaging (about 1 week after radioactive iodine): Bring the FOUR lens cases to the appointment 
so we can collect your contacts 
  
Ophthalmology Appointments:  
1st appointment: prior to radioactive iodine therapy  
2nd appointment: 8 months after therapy to assess for nasolacrimal duct obstruction  
3rd appointment: 16 months after therapy to assess for nasolacrimal duct obstruction  
4th appointment: 24 months after therapy to assess for nasolacrimal duct obstruction  
Date of IRB Approval: 03/08/2022
Date of Expiration: 03/07/2023


VUMC Institutional Review Board  
4 
Informed Consent Document for Research
Study Title:  
Effect of Artificial Tears on Radioiodine Levels in the Nasolacrimal Duct System of  
Patients Following Radioiodine Therapy for Thyroid Carcinoma  
Version Date:  
1/7/2022 
PI:  
Dr. Rachel Sobel  
  
This box is for 
IRB USE ONLY 
Do not edit or delete 
  
Payments for your time spent taking part in this study or expenses: 
One time $50 gift-card, given at the Nuclear Medicine follow-up appointment about 7 days from 
radioactive iodine therapy.   
Financial reimbursement to replace contact lenses if patient does not wear daily soft contact lenses 
Costs to you if you take part in this study: 
If you agree to take part in this research study, you and/or your insurance will not have to pay for the 
tests and treatments that are being done only for research.  However, you are still responsible for paying 
for the usual care you would normally receive for the treatment of your illness. This includes treatments 
and tests you would need even if you were not in this study. These costs will be billed to you and/or 
your insurance.   
You have the right to ask what it may cost you to take part in this study. If you would like assistance, 
financial counseling is available through the Vanderbilt Financial Assistance Program.  The study staff can 
help you contact this program. You have the right to contact your insurance company to discuss the 
costs of your routine care (non-research) further before choosing to be in the study. You may choose not 
to be in this study if your insurance does not pay for your routine care (non-research) costs and your 
doctor will discuss other treatment plans with you.  
Payment in case you are injured because of this research study: 
If it is determined by Vanderbilt and the Investigator that an injury occurred as a direct result of the tests 
or treatments that are done for research, then you and/or your insurance will not have to pay for the 
cost of immediate medical care provided at Vanderbilt to treat the injury.   
  
There are no plans for Vanderbilt to pay for any injury caused by the usual care you would normally 
receive for treating your illness or the costs of any additional care. There are no plans for Vanderbilt to 
give you money for the injury.   
  
Who to call for any questions or in case you are injured: 
If you should have any questions about this research study or if you feel you have been hurt by being a 
part of this study, please feel free to contact
 during working hours or my 
Faculty Attending Ophthalmologist
 during working hours. If you 
cannot reach the research staff, please page the ophthalmology department at
  
  
Date of IRB Approval: 03/08/2022
Date of Expiration: 03/07/2023


VUMC Institutional Review Board  
5 
Informed Consent Document for Research
Study Title:  
Effect of Artificial Tears on Radioiodine Levels in the Nasolacrimal Duct System of  
Patients Following Radioiodine Therapy for Thyroid Carcinoma  
Version Date:  
1/7/2022 
PI:  
Dr. Rachel Sobel  
  
This box is for 
IRB USE ONLY 
Do not edit or delete 
For additional information about giving consent or your rights as a person in this study, to discuss 
problems, concerns, and questions, or to offer input, please feel free to call the VUMC Institutional 
Review Board Office at (615) 322-2918 or toll free at (866) 224-8273.  
Reasons why the study doctor may take you out of this study:  
Your study doctor may take you out of this study if staying in the study would be harmful to you or if you 
fail to follow instructions.
  
What will happen if you decide to stop being in this study? 
If you decide to stop being part of the study, you should tell your study doctor.  Deciding to not be part 
of the study will not change your regular medical care in any way.  
Clinical Trials Registry:   
A description of this clinical trial will be available on www.clinicaltrials.gov, as required by U.S. Law.  This 
website will not include information that can identify you.  At most, the website will include a summary 
of the results.  You can search this Web site at any time.  
  
Confidentiality:    
Data will be de-identified without any personal information that could connect you to the data. All data 
and contact lens specimens will be stored in a secure location, which only the study personnel will have 
access to.   
  
This study may have some support from the National Institutes of Health (NIH). If so, your study 
information is protected by a Certificate of Confidentiality.  This Certificate allows us, in some cases, to 
refuse to give out your information even if requested using legal means.   
  
It does not protect information that we have to report by law, such as child abuse or some infectious 
diseases.  The Certificate does not prevent us from disclosing your information if we learn of possible 
harm to yourself or others, or if you need medical help.   
  
Disclosures that you consent to in this document are not protected. This includes putting research data 
in the medical record or sharing research data for this study or future research. Disclosures that you 
make yourself are also not protected.   
  
Date of IRB Approval: 03/08/2022
Date of Expiration: 03/07/2023


VUMC Institutional Review Board  
6 
Informed Consent Document for Research
Study Title:  
Effect of Artificial Tears on Radioiodine Levels in the Nasolacrimal Duct System of  
Patients Following Radioiodine Therapy for Thyroid Carcinoma  
Version Date:  
1/7/2022 
PI:  
Dr. Rachel Sobel  
  
This box is for 
IRB USE ONLY 
Do not edit or delete 
Privacy: 
Any samples and information about you may be made available to others to use for research.  To protect 
your privacy, we will not release your name.  You will not receive any benefit as a result of the tests done 
on your samples. These tests may help us or other researchers learn more about the causes, risks, 
treatments, or how to prevent this and other health problems.   
Study Results: 
Results of the study will be shared with the participants of the trial by telephone or during a clinic visit.  
  
Authorization to Use/Disclose Protected Health Information What 
information is being collected, used, or shared?  
To do this research, we will need to collect, use, and share your private health information.  By signing 
this document, you agree that your health care providers (including both Vanderbilt University Medical 
Center and others) may release your private health information to us, and that we may use any and all 
of your information that the study team believes it needs to conduct the study.  Your private 
information may include things learned from the procedures described in this consent form, as well as 
information from your medical record (which may include information such as HIV status, drug, alcohol 
or STD treatment, genetic test results, or mental health treatment).     
  
Who will see, use or share the information?  
The people who may request, receive or use your private health information include the researchers and 
their staff.  Additionally, we may share your information with other people at Vanderbilt, for example if 
needed for your clinical care or study oversight.  By signing this form, you give permission to the 
research team to share your information with others outside of Vanderbilt University Medical  
Center.  This may include the sponsor of the study and its agents or contractors, outside providers, study 
safety monitors, government agencies, other sites in the study, data managers and other agents and 
contractors used by the study team.   We try to make sure that everyone who sees your information 
keeps it confidential, but we cannot guarantee that your information will not be shared with others.  If 
your information is disclosed by your health care providers or the research team to others, federal and 
state confidentiality laws may no longer protect it.   
  
Date of IRB Approval: 03/08/2022
Date of Expiration: 03/07/2023


VUMC Institutional Review Board  
7 
Informed Consent Document for Research
Study Title:  
Effect of Artificial Tears on Radioiodine Levels in the Nasolacrimal Duct System of  
Patients Following Radioiodine Therapy for Thyroid Carcinoma  
Version Date:  
1/7/2022 
PI:  
Dr. Rachel Sobel  
  
This box is for 
IRB USE ONLY 
Do not edit or delete 
Do you have to sign this Authorization?  
You do not have to sign this Authorization, but if you do not, you may not join the study.  
  
How long will your information be used or shared?  
Your Authorization for the collection, use, and sharing of your information does not expire.  Additionally, 
you agree that your information may be used for similar or related future research studies.  
  
What if you change your mind?  
You may change your mind and cancel this Authorization at any time.  If you cancel, you must contact the 
Principal Investigator in writing to let them know by using the contact information provided in this consent 
form.  Your cancellation will not affect information already collected in the study, or information that has 
already been shared with others before you cancelled your authorization.  
If you decide not to take part in this research study, it will not affect your treatment, payment or 
enrollment in any health plans or affect your ability to get benefits. You will get a copy of this form 
after it is signed.  
  
STATEMENT BY PERSON AGREEING TO BE IN THIS STUDY 
I have read this consent form and the research study has been explained to me verbally.  All my 
questions have been answered, and I freely and voluntarily choose to take part in this study.    
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Date  
  
  
  
Signature of patient/volunteer   
  
  
  
  
  
Consent obtained by:    
Date of IRB Approval: 03/08/2022
Date of Expiration: 03/07/2023


VUMC Institutional Review Board  
8 
Informed Consent Document for Research
Study Title:  
Effect of Artificial Tears on Radioiodine Levels in the Nasolacrimal Duct System of  
Patients Following Radioiodine Therapy for Thyroid Carcinoma  
Version Date:  
1/7/2022 
PI:  
Dr. Rachel Sobel  
  
This box is for 
IRB USE ONLY 
Do not edit or delete 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Date  
  
  
  
Signature  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Printed Name and Title   
  
Time: ______________   
  
  
Date of IRB Approval: 03/08/2022
Date of Expiration: 03/07/2023

Prot_SAP_002.pdf: 
TITLE:  Effect of Artificial Tears on Radioiodine Levels in the Nasolacrimal Duct System of Patients Following Radioiodine Therapy 
for Thyroid Carcinoma 
 
April 17, 2020 
 
Coordinating Center: 
Vanderbilt University Medical Center 
Principal Investigator: 
Rachel Sobel, MD 
Vanderbilt University Medical Center 
1211 Medical Center Drive 
Nashville, TN, 37232, USA 
415-279-6578 
Rachel.k.sobel@vumc.org 
 
Study Coordinator: 
 
 
Megan Barrett 
615-875-4216 
megan.c.barrett.1@vumc.org 
 
 
Researchers: 
 
 
Irene Lee, MD 
817-715-2122 
Irene.lee@vumc.org 
 
Aaron Jessop, MD MBA 
Aaron.jessop@vumc.org 
 
Lindsey Bischoff, MD 
lindsay.bischoff@vumc.org 
 
Heather Cole, MD 
heather.cole.1@vumc.org 
 
 


 
1. 
OBJECTIVES 
 
1.1 
Primary Objectives 
 
1.1.1 To assess whether use of preservative free artificial tears following radioactive iodine administration will lower the level of 
radioactive iodine in the tears of patients treated with radioactive iodine for thyroid carcinoma.  
 
1.2 
Secondary Objectives 
 
1.2.1 Secondary objective is to deduce whether artificial tears would be an effective preventative intervention to decrease the risk of 
developing nasolacrimal duct stenosis, which has been associated with radioactive iodine administration. Patients will be 
monitored over time for development of nasolacrimal duct stenosis symptoms, such as epiphora or tear duct infections.  
 
2. 
BACKGROUND 
 
2.1 
Study Disease(s) 
Radioactive iodine is commonly used for the treatment of thyroid carcinoma. The association of radioiodine therapy for the treatment 
of differential thyroid carcinoma with nasolacrimal duct dysfunction has been well documented in many research studies.1–3 Doses of 
150 mCi or more, which are frequently used in the treatment of thyroid carcinoma, have been found to significantly increase a 
patient’s risk of developing nasolacrimal duct obstruction.2,4,5 Prior studies have estimated the incidence of radioactive iodine 
associated nasolacrimal duct obstruction to be around 3 to 4.6%.2,6 
 
Prior case reports have documented radioactive iodine detection in the tears of patients following radioiodine ablation for thyroid 
cancer.7,8 A likely mechanism is that the radioactive iodine is taken up from the tears by the stratified columnar epithelial cells of the 
lacrimal sac and nasolacrimal ducts, leading to inflammation and fibrosis, and subsequent stenosis and obstruction of the lacrimal 
lumen over time.9  
 
The purpose of this study is to explore whether administration of preservative free artificial tears will decrease the level of detectable 
radioiodine in the tears and nasolacrimal duct system of patients undergoing radioiodine therapy for differential thyroid carcinoma. 
There are no current studies analyzing what threshold of radioactive iodine in tears is considered to be less likely to cause 
nasolacrimal duct stenosis. Given that radioactive iodine uptake by the epithelial cells lining the lacrimal sac is the likely cause of 
subsequent fibrosis and obstruction, the hypothesis is that decreasing the concentration of radioactive iodine in tears as much as 


 
possible with artificial tears will thus decrease the risk of developing nasolacrimal duct obstruction. We believe that the lower the 
radioactive iodine level in tears, the lower the risk of developing nasolacrimal duct obstruction. 
 
We will recruit a total of 5 patients who wear bilateral disposable contact lenses, have them self-administer preservative free artificial 
tears in the right contact-wearing eye (left contact-wearing eye will receive no tears), and obtain their tear-containing contact lenses 
from both eyes and measure radioiodine levels.  
 
 
3. 
PATIENT SELECTION 
 
3.1 
Eligibility Criteria  
 
There will be no age restriction to this study.  
Inclusion Criteria (must meet all below to be recruited):  
1. Radio-iodine therapy for thyroid cancer 
2. Radioiodine therapy ≥150mCi  
3. Patient wears contacts on both eyes 
 
3.2 
Exclusion Criteria 
Exclusion Criteria:  
1. Use of eye drops, other than artificial tears 
2. History of ocular/lacrimal gland trauma  
3. History of lacrimal drainage disease: canaliculitis, dacryocystitis 
4. Prior radiotherapy  
5. Current or prior use of chemotherapy drugs (i.e. 5-fluorouracil, docetaxel) 
6. Medical conditions that predispose to NLD stenosis   
a. Sarcoid 
b. Granulomatosis with polyangiitis 
c. Chronic lymphocytic leukemia 
 
 
4. 
REGISTRATION PROCEDURES 
 


 
Patients will be identified through the Nuclear Medicine and/or Endocrine department. Patients who meet all inclusion criteria will be 
asked whether they would like to participate in the study.  
 
 
5. 
TREATMENT AND/OR IMAGING PLAN 
 
5.1 
Agent Administration 
 
Artificial tears are the study agent of interest and bear minimal risks and side effects. The regimen for self-administration of artificial 
tears is as follows: on Day 1, patients will self-administer artificial tears every 15 minutes for 2 hours followed by every 30 minutes 
for 4 hours. On Day 2, patients will self-administer artificial tears every 1 hour for 12 hours. On Day 3, patients will self-administer 
artificial tears four times that day. On Day 4, patients will self-administer tears twice that day. Patients will be instructed to wear 
their contact lenses throughout their waking hours. The rationale for this proposed regimen is to dilute the radioactive iodine from the 
tear ducts with frequent administration of artificial tears. Zettinig et al showed that radioiodine levels are highest in tears on the first 
day and significantly decrease over 4-5 days,8 which serves as the underlying rationale for having patients self-administer artificial 
tears for four days.  
 
Routine whole body scintigraphy (WBS) and/or single photon emission computed tomography (SPECT-CT) will be obtained around 1 
week post-radioiodine as part of the routine care patients receive after having radioiodine administration for treatment of thyroid 
cancer. No adjustments will be made to this routine imaging that patients receive. We will analyze the routine images for localization 
of radioiodine in the intranasal and nasolacrimal duct regions. 
 
 
5.1.1 Primary and Secondary Endpoint 
 
 The primary endpoint will be to assess for the development of nasolacrimal duct obstruction over two years in 8 month intervals. 
Every 8 months, each patient will be assessed in the ophthalmology clinic for nasolacrimal duct dysfunction via tear duct irrigation. 
The secondary endpoint is the level of radioactive iodine measured in the tears of patients collected via their contact lenses. Patients 
will be asked to store their daily contact lenses in sterile container for subsequent radioactive iodine level analysis via a well counter 
in the Nuclear Medicine department. These contact lenses will be collected at their 1 week routine appointment with Nuclear 
Medicine.  
 


 
 
5.1.2 Other Modality(ies) or Procedures 
 
Patients’ tears will be collected through contact lenses (4 days worth from both eyes of each patient), which will be stored in unused 
contact lens containers daily and subsequently collected during routine 1 week follow-up appointments with Nuclear Medicine. The 
lenses will be analyzed for radioactive iodine levels. Routine post-radioiodine imaging (single-photon emission computed tomography 
and/or whole body scintigraphy) will be obtained to assess for radioactivity in the nasolacrimal or intranasal region.  
 
6. 
STATISTICAL CONSIDERATIONS 
 
Radioactive iodine levels from the right contact lenses of patients will be compared to that of the left contact lenses that did not have 
exposure to artificial tears. The data gathered will be analyzed by the statistics personnel in the department of Ophthalmology.  
 
In more detail: the area under the curve (AUC) of all four days for each patient was calculated as the sum of the four trapezoid areas 
under the I-131 exposure values. To meet the normality assumption, I-131 activities and AUCs were logarithmically transformed to 
obtain geometric mean I-131 activities of each day and geometric mean AUCs. The Shapiro-Wilk test was used to evaluate the normal 
assumption for logarithmically transformed AUCs (log-AUCs). The 95% confidence intervals (CI) of the AUCs were constructed for 
the right experimental eyes and left control eyes, assuming normality for log-AUCs, which were compared between the two groups 
using paired t-tests. Statistical analyses were conducted using R version 4.1.2 (R Project for Statistical Computing, www.r-
project.org). Two sided p<0.05 was considered statistically significant.  
 
 
7. 
ADVERSE EVENTS:  LIST AND REPORTING REQUIREMENTS  
Preservative- free artificial tears have rare side effects. Because they are preservative free, there is minimal harm to the cornea. 
Possible side effects include watery eyes, possible allergic reaction, eye irritation not present before use of the artificial tears, or 
possible blurry vision. Persistent irritation of the eyes is an indication for stopping artificial tears.  These side effects will likely end 
with discontinuation of the artificial tears and are unlikely to have long-term sequela.  
 
There have been no studies conducted regarding the dose delay or dose reduction of artificial tears. It is possible that increasing the 
frequency of administration of artificial tears may increase the risk of developing the above possible side effects.  
 
 


 
8. 
STUDY OVERSIGHT AND DATA REPORTING / REGULATORY REQUIREMENTS 
 
The Vanderbilt-Ingram Cancer Center (VICC) oversees patient safety and data monitoring for its investigator-initiated and NIH-NCI 
funded clinical trials through its Data and Safety Monitoring Committee (DSMC). The purpose of the DSMC is to ensure the efficient 
implementation and management of VICC Data and Safety Monitoring Plan (DSMP). The Committee maintains authority to intervene 
in the conduct of studies as necessary to ensure clinical research performed at VICC achieves the highest quality standards. 
The VICC DSMC meets on a quarterly basis and ad hoc to discuss data and safety monitoring of clinical trials and to oversee the 
VICC DSMP. Internal audits for compliance with adverse event reporting, regulatory and study requirements, and data accuracy and 
completion are conducted according to the VICC DSMP according to study phase and risk. The committee reviews all serious adverse 
events (SAE) on Vanderbilt sponsored investigator-initiated studies on a quarterly basis and provides DSMC SAE review reports to 
the Vanderbilt IRB. 
 


 
9. 
REFERENCES 
1.  Solans R, Bosch JA, Galofré P, et al. Salivary and lacrimal gland dysfunction (sicca syndrome) after radioiodine therapy. J Nucl 
Med. 2001;42(5):738-743. 
2.  Kloos RT, Duvuuri V, Jhiang SM, Cahill KV, Foster JA, Burns JA. Nasolacrimal drainage system obstruction from radioactive 
iodine therapy for thyroid carcinoma. J Clin Endocrinol Metab. 2002;87(12):5817-5820. doi:10.1210/jc.2002-020210 
3.  da Fonseca FL, Yamanaka PK, Kato JM, Matayoshi S. Lacrimal System Obstruction After Radioiodine Therapy in Differentiated 
Thyroid Carcinomas: A Prospective Comparative Study. Thyroid. 2016;26(12):1761-1767. doi:10.1089/thy.2015.0657 
4.  Al-Qahtani KH, Al Asiri M, Tunio MA, et al. Nasolacrimal duct obstruction following radioactive iodine 131 therapy in 
differentiated thyroid cancers: review of 19 cases. Clin Ophthalmol. 2014;8:2479-2484. doi:10.2147/OPTH.S71708 
5.  Ali M. Iodine-131 Therapy and Nasolacrimal Duct Obstructions: What We Know and What We Need to Know. Ophthalmic 
Plastic and Reconstructive Surgery. 2016;32(4):243-248. doi:10.1097/IOP.0000000000000647 
6.  Burns JA, Morgenstern KE, Cahill KV, Foster JA, Jhiang SM, Kloos RT. Nasolacrimal obstruction secondary to I(131) therapy. 
Ophthalmic Plast Reconstr Surg. 2004;20(2):126-129. 
7.  Bakheet SM, Hammami MM, Hemidan A, Powe JE, Bajaafar F. Radioiodine secretion in tears. J Nucl Med. 1998;39(8):1452-
1454. 
8.  Zettinig G, Karanikas G, Hanselmayer G, Havlik E, Dudczak R. Radioactive contamination of contact lenses during radioiodine 
therapy. Nucl Med Commun. 2000;21(10):955-957. 
9.  Ali MJ, Vyakaranam AR, Rao JE, Prasad G, Reddy PVA. Iodine-131 Therapy and Lacrimal Drainage System Toxicity: Nasal 
Localization Studies Using Whole Body Nuclear Scintigraphy and SPECT-CT. Ophthalmic Plast Reconstr Surg. 2017;33(1):13-
16. doi:10.1097/IOP.0000000000000603