Clinical trial NCT02872012
Conditions: Ocular Anesthesia
Sponsor: University of Michigan
Start date: 2016-03-01; Completion date: 2018-06-01
Enrollment: 23 participants; Allocation: RANDOMIZED; Intervention model: PARALLEL

Brief summary:
The cryoanesthesia (CA) device is designed to provide anesthesia to a focal area on the surface of the eye immediately prior to intraocular injections.

The investigators plan to carry out a pilot study to collect preliminary data on the effectiveness of the cryoanesthesia (CA) device in minimizing the pain caused by intravitreal injections (IVT).

Detailed description:

Arms: arm 1: All patients will have one eye randomized to receiving anesthesia via the cryoanesthesia device which anesthetizes by chilling rather than by use of drug, prior to receiving an intravitreal injection.

Comment: Cryoanesthesia Device is the name of the device. arm 2: All patients will have one eye randomized to receiving anesthesia via the cryoanesthesia device which anesthetizes by chilling rather than by use of drug, prior to receiving an intravitreal injection.

Comment: Cryoanesthesia Device is the name of the device. arm 3: All patients will have one eye randomized to receiving anesthesia via the cryoanesthesia device which anesthetizes by chilling rather than by use of drug, prior to receiving an intravitreal injection.

Comment: Cryoanesthesia Device is the name of the device. arm 4: All patients will have one eye randomized to receiving anesthesia via the cryoanesthesia device which anesthetizes by chilling rather than by use of drug, prior to receiving an intravitreal injection.

Comment: Cryoanesthesia Device is the name of the device. arm 5: All patients will have one eye randomized to receiving anesthesia via the cryoanesthesia device which anesthetizes by chilling rather than by use of drug, prior to receiving an intravitreal injection.

Comment: Cryoanesthesia Device is the name of the device. arm 6: Participants randomized to this arm will have their other eye receive anesthesia via the current standard of care treatment method (lidocaine) prior to receiving an intravitreal injection.

Lidocaine: Lidocaine will be applied to the non-cryoanesthesia eye.
Interventions: intervention 1: Cryoanesthesia device intervention 2: Lidocaine
Intervention descriptions: intervention 1: The study will be carried out in patients receiving bilateral injections. One eye will be anesthetized using the cryoanesthesia device, developed at the University of Michigan. This has been assessed to be a Non-significant Risk device. intervention 2: Lidocaine applied to the non-cryoanesthesia eye.

Protocol documents:
Prot_000.pdf: 
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Cryoanesthesia for Intravitreal Injections 
 
PI: Anjali Shah, MD 
 
NCT02872012 
 
 
 
 
 
Protocol Version 4.0 
 
IRB Approved 11Apr2018 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


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Cryoanesthesia for Intravitreal Injections 
PI: Anjali Shah, MD 
 
1.0  Purpose of the Investigation (Background): 
In 2004, Friedman and colleagues (Friedman, O'Colmain et al. 2004) applied age, ethnicity, and 
gender specific rates of age-related macular degeneration to the 2000 US census and estimated that 
1.75 million Americans had exudative macular degeneration. Population based estimates suggest that 
this number will increase to 2.95 million or more by the year 2020. Using these same principles 
Western Europe was estimated to have over 3.3 million patients with exudative macular degeneration 
in 2004. These numbers are likely underestimates of the true prevalence of this disease. The majority 
of these patients are receiving intravitreal injection therapy (IVT) multiple times per year in one or 
both eyes. Recent studies have demonstrated that IVT is at least as successful as laser therapy in 
treating vision threatening retinal disease in patients with diabetic retinopathy and retinal vein 
occlusions, resulting in IVT becoming the standard of care in these patients as well. In addition, there 
are several novel therapies in clinical trials that utilize intravitreal delivery.   
The rapidly growing demand for IVT has led to severe strain on clinic work flow, as IVT is a time 
consuming procedure. Ophthalmologists perform these injections in busy clinics, frequently treating 
60 to 70 patients a day. These injections are painful, and ophthalmologists typically choose various 
methods of anesthesia for IVT. The standard of care (SOC) is to provide anesthesia by either applying 
cotton-tipped applicators soaked in lidocaine, applying lidocaine gel, or giving a subconjunctival 
lidocaine injection. These methods of anesthesia increase the time for patient preparation by several 
fold. The other commonly used option is to provide anesthesia via topical eye drops, which is more 
time efficient, but may result in patient discomfort (Blaha, Tilton et al. 2011, Davis, Pollack et al. 
2012, Sanabria, Montero et al. 2013, Xing, Dorrepaal et al. 2014). Developing a device to provide 
rapid anesthesia of the ocular surface will improve patient comfort and physician efficiency. A recent 
case report on a patient with an allergy to lidocaine demonstrated that excellent anesthesia is possible 
with the application of ice to the ocular surface.(Lindsell, Miller et al. 2014) The cryoanesthesia 
device provides very focal, rapid cooling, resulting in a safer, more reproducible, and more effective 
way of delivering anesthesia to the ocular surface. With over 8 million injections given annually in the 
United States alone, the impact of this device would be significant.   


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1.1 
Name of Investigational Device: 
Cryoanesthesia device 
1.2 
Intended Use of the Investigational Device: 
The cryoanesthesia (CA) device is designed to provide anesthesia to a focal area on the surface of 
the eye immediately prior to intraocular injections. The device is a portable, handheld device that 
utilizes thermoelectric cooling to rapidly anesthetize a 4x4 mm area on the surface of the eye. It is 
designed to decrease patient discomfort before, during, and after intraocular injections compared to 
current anesthetic methods.  
1.3 
Risk Analysis: 
Safety Studies: 
Our confidence in our ability to create a safe device is based on clinical studies that occurred with 
the advent of cryotherapy to treat ocular tumors and retinal tears. The goal of cryotherapy to treat 
retinal tears and choroidal and retinal tumors is to create tissue destruction, and the initial pre-
clinical and clinical safety studies of these therapies provided a wealth of histopathologic data that 
has guided our initial safety studies. Chi and Kelman (Chi and Kelman 1967) studied corneal 
endothelial viability following the application of cryotherapy at various temperatures to the cornea 
for 20 seconds. They reported no endothelial cell loss at -10°C with largely reversible cell loss at 
-20°C. Irreversible endothelial cell loss occurred at the temperature of -80°C, particularly in eyes 
treated with a larger probe tip. Maumenee and colleagues (Maumenee and Kornblueth 1949) carried 
out a safety study looking at the toxicity of -78°C applied to a rabbit cornea for 5 seconds (6 mm 
treatment spot). They found cellular damage within the first 5 days that completely resolved at days 
10 and 12. Curtin and colleagues (Curtin, Fujino et al. 1966) examined the effect of -40°C applied to 
rabbit sclera via histopathology. The temperature was applied until retinal whitening was seen 
(generally 10-20 seconds). The authors reported minor cell loss at days 2 and 4 post treatment. 
These changes were no longer apparent at days 7, 14, and 21 post treatment. In a separate study, 
scleral bursting strength was found to remain stable following 6 cryotherapy treatments of -60°C 
applied for 1 minute each.(Beckman, Leff et al. 1975)  
More recently, cryotherapy histopathologic damage on human cadaveric eyes was studied using 
atomic force microscopy. 3 eyes were sectioned into 30 scleral sections. A cryoprobe at -80°C was 
used for treatments. Three groups were treated for 5, 10, or 20 seconds respectively (N=6 in each 
group). One group received a sham treatment (room temperature probe applied to sclera, N=6) and 
one group did not come into contact with the probe (control, N=6). All scleral sections were 
examined via atomic force microscopy. Lee and colleagues found that eyes treated at -80°C for 5 
seconds showed mild changes in scleral thickness and collagen fibril density (mild increase due to 
inflammation). These changes were more marked in the eyes treated for 10 or 20 seconds. Eyes 
treated for 5 seconds had no significant nanostructural differences in the diameter of collagen fibrils 
compared to controls. There were significant changes in eyes treated for 10 or 20 seconds. (Lee, 
Choi et al. 2013) This study showed that temperatures that are designed to cause tissue damage, and 
are many times colder than our device is capable of achieving, do not cause significant damage if 
applied for short periods of time. Studies of cryosurgery have demonstrated reversible nervous 
system blockade at temperatures ranging from 0°C to -10°C, with no pathologic tissue 
damage.(Garamy 1967)  
Testing Completed – Animal Safety Study: 
Our team completed preliminary safety testing using a specialized and more powerful non-portable 
prototype with the capability of achieving temperatures as cold as -40°C. We treated 20 New 
Zealand rabbits, utilizing 2 treatment times (10 and 30 seconds) and the following 10 temperatures: 
20°C, 0°C, -5°C, -10°C, -15°C, -20°C, -25°C, -30°C, -35°C and -40°C. Each rabbit received 


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treatments just posterior to the limbus at the 1:30, 4:30, 7:30, and 10:30 meridians in both eyes. A 
total of 10 animals were included in phase 1, and each rabbit received 4 treatments per eye for 30 
seconds. A total of 10 animals were included in phase 2, and each rabbit received 4 treatments per 
eye for 10 seconds. All animals were sacrificed 1 week following application of the cryo-anesthesia 
probe. The eyes were removed and sent to Comparative Biosciences Inc. for processing and 
histopathologic evaluation.  
Comparative Biosciences, Inc. offers GLP and non-GLP preclinical toxicology, efficacy, 
pharmacology, pharmacokinetics-pharmacodynamics, histopathology, and safety studies on all 
laboratory species. They are a fully-staffed, state-of-the-art, AAALAC-accredited purpose-built 
facility with both an in house histopathology laboratory and a full time quality assurance unit. They 
are registered with the FDA, USDA, and OLAW. Histopathology was read by certified veterinary 
pathologist.   
None of the eyes manifested signs of clinical toxicity immediately following treatment. 
Histopathologic toxicity at the limbal zone was minimal and consisted of small microhemorrhage, 
with scattered lymphocytes and monocytes and some local edema seen in a few eyes. The majority 
of these findings were located in myocytes. However, no ocular muscles were treated in any animal 
during this study. The pathologic findings of focal hemorrhage, inflammation, and myocyte damage 
relate to artifact/crush injuries to the muscles/ocular surface that occurred using 0.5 forceps to 
position the eyes of the anesthetized rabbits in a way that permitted exposure of the treatment sites 
(Fig 1). In all eyes, the anterior segment (cornea, iris, ciliary process, lens and sclera were 
within normal limits, as was the retina and optic nerve. Of note, none of the eyes treated with -
40C for 10 seconds had any histopathologic findings. The coldest temperature planned for the 
proposed study is -10C (23F) for 20 seconds.  
 
Figure 1 | Site of cryotherapy treatment, preclinical safety study 
 
 
Risks of the Proposed Study: 
The primary risks patients will be exposed to relate to those that occur with IVT (SCH, conjunctival 
hyperemia and injection, and corneal keratopathy). The risks of the CA device include mild ocular 
discomfort secondary to the cold temperature.  
All patients will receive topical anesthetic drops (proparacaine) prior to focal anesthesia (either CA 
or SOC). These drops will help reduce the occurrence of pre-injection discomfort. The topical 
anesthetic drop will provide baseline anesthesia if there is minimal anesthetic effect achieved by 
cryoanesthesia. Topical proparacaine use as stand-alone anesthesia prior to intravitreal injections is 
one of the common methods of providing anesthesia and is considered within the standard of care 
for intravitreal injections (Blaha et al., 2011, Davis 2012).  
Patients receiving SOC undergo the risk of increased corneal keratopathy. In addition, patients 
receiving the SOC have an increased risk of post injection pain. The risk of mild ocular discomfort 


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with CA is mitigated by the use of proparacaine and also poses less risk to patients than topical 
lidocaine.   
   1.3.1  Primary Objective: 
We plan to carry out a pilot study to collect preliminary data on the effectiveness of the 
cryoanesthesia (CA) device in minimizing the pain caused by intravitreal injections (IVT) and 
determine the most effective temperature and time of treatment. Specifically, we intend to 
record patients’ subjective injection pain. The study will be carried out in patients receiving 
bilateral injections, and one eye will be anesthetized using the CA device, with the fellow eye 
receiving anesthesia via a topical lidocaine gel (SOC), a common method of providing 
anesthesia in current clinical practice. 
   1.3.2 Exploratory Objective(s): 
We will measure injection preparation pain, 4-hr, and 24-hr post injection pain. Patients will 
rate ocular irritation immediately after injection as well as 4 and 24 hours after injection (1 – 
no irritation; 2 – mild irritation 3 – moderate irritation 4- marked irritation). Patients will rate 
visual function in the treated eye immediately after injection as well as 4 and 24 hours after 
injection (1 – no changes from baseline; 2 – mild blurring of vision 3 – moderate blurring of 
vision 4- marked blurring of vision).  Physicians will record patients’ objective response to 
intraocular needle penetration (1 – no pain/movement; 2 – mild pain/movement 3 – marked 
pain/movement with the injection). In addition, physicians will record the following common 
ocular side effects following IVT: subconjunctival hemorrhage (SCH), conjunctival 
hyperemia, and conjunctival injection. These will be assessed via a slit lamp examination 
performed within 30 minutes and 24 hours of the administration of the intravitreal injection. In 
addition, each eye will be assessed for other signs of anterior segment toxicity, including AC 
reaction or hypotony. Patients will be examined or receive a call 1 week after the injection to 
assess any adverse effects.  
1.4 
Anticipated duration of the clinical investigation: 
We plan to recruit 40 patients for this study, and each patient will receive a single injection in each 
eye. Most patients receiving bilateral injections receive both injections in a 1-2 week period (1 eye at 
day 0, and the second eye by day 14). This is the current standard period between intravitreal 
injections, and is used regardless of the form of local anesthesia delivered. Some patients receive 
bilateral injections during the same clinic visit. First eye treatment will be randomly assigned to one 
of the CA treatment groups and the other eye will be randomly assigned to SOC.  
2.0 
 Study Design: 
2.1    General Study Design: 
 
Prospective, interventional pilot study. 
 
2.1.1 
Study Design Schematic: 


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          2.2   Subject Selection: 
 
2.2.1 
General characteristics of the proposed subject population(s): 
Patients age >18 years old with bilateral macular disease due to either exudative 
macular degeneration or diabetic retinopathy requiring bilateral IVT and who had at 
least one prior IVT. To be included in this study, patients must be able to give 
informed consent.  
 
Patients with bilateral macular disease requiring bilateral IVT will enable us to 
compare the effectiveness of CA compared to SOC in terms of pain reduction, with 
each patient serving as their own control.  
 
2.2.2 
Anticipated Number of Research Subjects: 
We anticipate recruiting and enrolling 40 patients to complete this study (10 for each 
CA group). We expect that all 40 patients will complete the study.  
 
2.2.3 
Inclusion Criteria: 
Inclusion criteria: Patients age >18 years old with bilateral macular disease due to 
either exudative macular degeneration or diabetic retinopathy requiring bilateral IVT. 
Only patients with at least one previous IVT will be recruited.  To be included in this 
study, patients must be able to give informed consent.  
 
2.2.4  Exclusion Criteria: 
Exclusion Criteria: Patients < 18 years of age. Patients with unilateral disease, or 
patients with bilateral disease who are not able to give informed consent. Patients with 
preexisting conjunctival, episcleral or scleral defects or disease will be excluded. 
 
2.3  Study Procedures: 
Pilot Study
40 patients receiving bilateral IVT
Eye 1
Cryoanesthesia
Group 1:
Temp: -7°C
Cooling 
Time: 20 sec
Group 2:
Temp: -5°C
Cooling 
Time: 20 sec
Group 3:
Temp: -10°C
Cooling 
Time: 20 sec
Group 4:
Temp: -10°C
Cooling 
Time: 10 sec
Eye 2
Standard of 
Care (SOC)
Lidocaine Gel


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2.3.1 
Screening Procedures: 
 
 
Physician will verify the need for IVT prior to beginning the study. 
 
2.3.2 
Study Treatment or Diagnostic Product Procedures: 
Device Overview:  
The cryoanesthesia device is a handheld instrument measuring approximately 10 
inches in length and 1.5 inches in diameter. A 4×4 mm area at the tip of the device is 
placed against the eye and cooled to the temperature setpoint (e.g., -5°C, -7°C, or -
10°C) via activation of a switch on the device. Cooling slows conduction of pain 
fibers in the conjunctiva (outermost layer of the eye) and the sclera (white of the eye) 
to a depth less than a millimeter. The key features of the device include a temperature 
regulating feedback loop to maintain highly accurate temperature control and a 
lockout mechanism to prevent excessive cooling. Two small protrusions on the tip 
leave temporary indentations on the surface of the eye to guide subsequent placement 
of the intravitreal needle. The cooling region of the device is located on a replaceable 
metal tip. An “ON” switch is first activated to cool the contact region of the device, 
after which this region is placed against the eye, initiating rapid cooling to anesthetize 
the injection site while simultaneously marking the cooled location. After the 
specified cooling time is reached, the device is removed, immediately after which the 
physician performs intravitreal injection.    
 
 
 
 
Instructions for administering CA: 
All physicians taking part in this study will receive a practical training session on use 
of the prototype prior to study initiation to ensure that they are comfortable operating 
the device.   
 
Injection procedure: 
After obtaining written consent, the brow above the eye to receive intravitreal 
treatment will be marked. Next, one drop of proparacaine will be applied into the eye 
to at least 5 minutes before any additional steps. Once the patient is ready, another 
drop of proparacaine will be applied and the physician or his assistant will then swab 
the lids with betadine. The physician will place a lid speculum in the patient’s eye. A 
drop of betadine will be applied at the site of treatment. The physician or his assistant 
will then activate the CA device by pressing the main button. He or she will review 
the LED display to verify that the device is set to achieve the correct temperature and 
time setpoints depending on the arm of the study to which the patient is randomized. 
The physician will adjust the temperature and time set points using the main device 
button if they are not correctly entered. The physician will then verbally review the 
selected treatment temperature and time, after which he or she will activate the device 
to enable the device tip to reach the required temperature. Immediately prior to 
placing the device tip against the eye, the physician will press the activation switch, 
after which he or she will apply the device to the surface of the eye. When the timer 
sounds, he or she will remove the device from the surface of the eye. The device tip 
has markers on it that will leave a temporary indentation 3 and 4 mm from the limbus. 
Immediately before giving the injection, the physician will place a drop of betadine on 
the surface of the eye at the site marked for the injection and wait 20 seconds. The 
physician will then give the intravitreal injection.  
 
The procedure for the patients receiving SOC will be similar to that described above. 
After obtaining written consent, the brow above the eye to receive intravitreal 


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treatment will be marked. Next, one drop of proparacaine will be applied into the eye 
to receive at least 5 minutes before any additional steps. Once the patient is ready, 
another drop of proparacaine will be applied and the physician or his assistant will 
then swab the lids with betadine. The patient will then have lidocaine gel placed on 
the eye and left in place for a minimum of 3 minutes prior to IVT. The 3-minute 
waiting period is needed to allow the lidocaine gel to diffuse through the sclera. 
Following completion of numbing, the eyelids will be swabbed with betadine and the 
physician will place the lid speculum. The physician will use a caliper to measure 3 or 
4 mm from the limbus of the eye, place a drop of betadine over this spot, wait 20 
seconds and then administer the injection.  
2.3.2.1 Allocation to Treatment: 
Patients will be randomly assigned to 1 of the 4 CA treatment groups and the 
SOC arm. Patients will be randomized to have their first eye receive either 
CA or SOC.  
 
 2.3.2.2 Treatment Adherence/Study Compliance:  
If a patient is does not require, or refuses, an injection in either eye, they will 
be removed from the study. Because IVT prevents blindness, the refusal of 
IVT is extremely rare. In addition, it is extremely rare for patient who have 
been determined to need IVT to have improvement in vision prior to IVT. 
If patients withdraw from the study, we will plan to recruit additional patients 
to replace them.  
 
2.3.3 
Follow-up Procedures: 
 
   2.3.3.1 Procedures to Assess Efficacy: 
Patients will record their subjective pain (pre-injection preparation pain, 
injection pain, and 24 hr post injection pain) using a visual analog scale (1 to 
10, with 10 being severe pain and 1 being no pain). The study coordinator will 
call the patients within 4 hours after their injection to review their 4-hr post 
procedure pain scores with them. Patients will be asked to return in 24 hours 
for anterior segment examination and 24-hr post injection pain assessment. 
Patients treated on Friday will be asked to return on Saturday for their 24-hr 
post injection assessment.  
 
 
2.3.3.2 
Procedures to Assess Safety: 
Physicians will record the following common ocular side effects following 
IVT: SCH, conjunctival hyperemia, and conjunctival injection. These will be 
assessed via a slit lamp examination performed within 30 minutes and 24 
hours of the administration of the intravitreal injection. Patients will undergo 
an anterior segment ocular examination 1 day following their intravitreal 
injection, and the physician will again record the presence of SCH, 
conjunctival hyperemia, conjunctival injection, and corneal keratopathy. In 
addition, each eye will be assessed for other signs of anterior segment 
toxicity, including AC reaction or hypotony. Patients will be assessed by a 
phone call 1 week after injection in each eye for any adverse events. 
 
Physicians will score ocular side effects of CA and SOC. We will conduct 
interim analysis every 12 weeks or following every 10th patient treated, 
whichever happens first, and will suspend the study if there appears to be 
significantly more ocular side effects following CA. For the reasons laid out 


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above (in the device description), we believe this device is minimal risk and 
has a very low probability of causing ocular side effects.  
 
 
2.4 
Study Outcome Evaluations: 
 
 
2.4.1 
Study Endpoints. 
Primary Endpoint:  
1. Injection pain - Pain rating on a visual analogue scale (1 to 10) 
 
Exploratory Endpoints: 
1. Injection preparation pain - Pain rating on a visual analogue scale, 1 to 10. 
2. 4-hr post injection pain - Pain rating on a visual analogue scale, 1 to 10. 
3. 24-hr post injection pain - Pain rating on a visual analogue scale, 1 to 10. 
4. Physician recorded time from initiation of treatment to completion of the 
intravitreal injection.  
5. Physician scored patient response to pain (1: no pain/movement; 2: mild 
pain/movement 3: marked pain/movement with the injection) 
6. Physician scored ocular side effects within 30 minutes of administration of the 
intravitreal injection and 1 day following the injection (SCH, conjunctival 
hyperemia, conjunctival injection, and corneal keratopathy): 1: No ocular side 
effects; 2: mild ocular side effects (trace to 1+ SCH, conjunctival hyperemia, 
conjunctival injection, or corneal keratopathy; 3: Marked ocular side effects (SCH 
involving at least 25% of the ocular surface, 2-4+ conjunctival hyperemia or 
conjunctival injection, or 2-4+ corneal keratopathy). In addition, each eye will be 
assessed for other signs of anterior segment toxicity, including AC reaction or 
hypotony. 
7. Time required to deliver IVT. The assistant will start timing the procedure from 
immediately after proparacaine instillation into the eye until after the eye receives 
IVT.  
8. Patients rating of ocular irritation immediately after injection as well as 4 and 24 
hours after injection: 1 – no irritation; 2 – mild irritation 3 – moderate irritation 4- 
marked irritation.  
9. Patients rating of visual function in the treated eye immediately after injection as 
well as 4 and 24 hours after injection: 1 – no changes from baseline; 2 – mild 
blurring of vision 3 – moderate blurring of vision 4- marked blurring of vision. 
 
 
2.4.2 
Outcome Data and Data Analysis: 
Primary Endpoint: Pain rating on a visual analogue scale (1 to 10): 1, no pain, to 10, 
severe pain. 
Exploratory Endpoints:  
1. Pain rating on a visual analogue scale (1 to 10): 1, no pain, to 10, severe pain. 
2. Physician recorded time from initiation of treatment to completion of the 
intravitreal injection. 
3. Physician scored patient response to pain (1 – no pain/movement; 2 – mild 
pain/movement 3 – marked pain/movement with the injection) 
4. Physician scored ocular side effects within 30 minutes of administration of the 
intravitreal injection and 1  day following the injection (SCH, conjunctival 
hyperemia, conjunctival injection, and corneal keratopathy): 1 No ocular side 
effects; 2 mild ocular side effects (trace to 1+ SCH, conjunctival hyperemia, 
conjunctival injection, or corneal keratopathy; 3. Marked ocular side effects (SCH 


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involving at least 25% of the ocular surface, 2-4+ conjunctival hyperemia or 
conjunctival injection, or 2-4+ corneal keratopathy). In addition, each eye will be 
assessed for other signs of anterior segment toxicity, including AC reaction or 
hypotony.  
5. Time from anesthesia initiation (proparacaine drops) to IVT delivery.  
6. Patients rating of ocular irritation immediately after injection as well as 4 and 24 
hours after injection: 1 – no irritation; 2 – mild irritation 3 – moderate irritation 4- 
marked irritation.  
7. Patients rating of visual function in the treated eye immediately after injection as 
well as 4 and 24 hours after injection: 1 – no changes from baseline; 2 – mild 
blurring of vision 3 – moderate blurring of vision 4- marked blurring of vision.   
3.0        Reporting of Adverse Effects to the IRB:   
In accordance with applicable policies of the University of Michigan Institutional Review Board 
(IRBMED), the investigator-sponsor will report, to the IRB, any observed or volunteered adverse 
effect that is determined to meet all of the following criteria: 1) associated with the investigational 
device or, if applicable, other study treatment or diagnostic product(s); 2) a serious adverse effect; 
and 3) an unexpected adverse effect.  Adverse event reports will be submitted to the IRB in accordance 
with the respective IRB procedures.  
Applicable adverse effects will be reported to the IRB as soon as possible and, in no event, later than 
10 calendar days following the investigator-sponsor’s receipt of the respective information.  Adverse 
effects which are 1) associated with the investigational drug or, if applicable, other study treatment or 
diagnostic product(s); 2) fatal or life-threatening; and 3) unexpected will be reported to the IRB 
within 24 hours of the investigator-sponsor’s receipt of the respective information.  
Follow-up information to reported adverse effects will be submitted to the IRB as soon as the relevant 
information is available.  If the results of the sponsor-investigator’s follow-up investigation show that 
an adverse effect that was initially determined to not require reporting to the IRB does, in fact, meet 
the requirements for reporting; the investigator-sponsor will report the adverse effect to the IRB as 
soon as possible, but in no event later than 10 calendar days, after the determination was made. 
 
3.1      Withdrawal of Subjects Due to Adverse Effects: 
Patients will only have a single exposure to the device (10 to 20 seconds in length). Should a 
patient not tolerate the discomfort of the cold tip for the entire duration and be unable to 
receive full CA, that patient would be removed from the study.  
If a patient withdraws from the study, the patient data will be destroyed.  Another patient will 
be recruited to take their place, provided that the additional patient can be recruited and treated 
within the allotted study time frame.  
 
 
3.2     Monitoring Plan: 
This monitoring plan will be followed in monitoring the University of Michigan as a single 
site approved for performance of a Nonsignificant Risk Device protocol under FDA guidance 
for Significant and Nonsignificant Riske devices, entitled, Cryoanesthesia. As the scope of 
this study is utilizing a Nonsignificant risk device involving 40 adults, this monitoring plan 
will be performed by the Sponsor-Investigator (S-I). The monitoring frequency shall be as 
follows: after 20 participants have been enrolled and again after all 40 patients have been 
enrolled. 
 
 
 
 
 
 
Purpose: 
The purpose of the monitoring plan is to facilitate compliance with good clinical practices, 
FDA guidelines and regulations which require monitors to verify the following: 


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 
The rights and well-being of participants are protected 
 
Reported data are accurate, complete, and verifiable from source documents 
 
Trial conducted in compliance with currently approved protocol and other applicable 
regulatory requirements 
 
This document identifies key monitoring activities and specifies the date to be reviewed over 
the course of a clinical trial.  
 
 
 
 
Site initiation and Qualification: 
 
 
 
Prior to study initiation, the S-I will review the following information: 
 
IRB approved version of the approved protocol for the study 
 
IRB approved Informed Consent Forms and processes 
 
AE and SAE definitions and reporting procedure, including plans for S-I review of all 
adverse events. It is recommended that the S-I contact the Michigan Institute for Clinical 
and Health Research IND/IDE Assistance Program (MIAP) for assistance with any 
reporting requirements to the FDA.  
 
CRF completion and maintenance process 
 
Creation and organization of the Investigator Study Binder 
 
Device accountability (e.g. access to storage, storage location, and dispensing of the device) 
will be maintained in study records. If not, the study records, state where the investigational 
product accountability records will be maintained.  
 
 
 
 
Interim Monitoring: 
At the two study team meetings (after enrollment of 20 subjects and again after enrollment has 
been completed), the S-I will review the following: 
 
Informed consent obtained for each participant 
 
Adherence to protocol eligibility criteria 
 
CRF completion 
 
Documentation of device use on the subject 
 
Monitor data and quality through routine review of submitted data to identify and follow-
up on missing data, inconsistent data, or data outliers 
 
Check and review of the regulatory binder and all essential documents 
 
Review of all SAEs and subject withdrawals 
 
Enrollment issues and targets 
 
Protocol amendments and their approval by the IRB 
 
Protocol deviations 
 
Personnel changes and required training 
 
Verifying continuous institutional review board (IRB) approval 
 
Any other issue as deemed important to the conduct of the study 
 
 
 
 
Reporting and Follow-up: 
If there are any significant findings, the S-I will follow-up any noncompliance, potential 
noncompliance, data irregularities, or other deficiencies identified along with a description of 
any actions taken, to be taken, or recommended, including the person responsible for 
completing actions and the anticipated date of completion. 
 
4.0 
Description of the Investigational Device: 
Prototype Description:  


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The cryo-anesthesia device is a handheld instrument measuring approximately 10 inches in length and 
1.5 inches in diameter, and weighing 0.8 pounds. A 4×4 mm2 area at the tip of the device is placed 
against the eye and cooled to a user-specified temperature setpoint between -5 and -10°C via 
activation of a switch on the device (Figure 2). The temperature setpoint is selected prior to device 
activation. Ocular surface cooling slows conduction of pain fibers in the conjunctiva (outermost layer 
of the eye) and the sclera (white of the eye) to a depth less than a millimeter. The key features of the 
device include a temperature regulating feedback loop that maintains highly accurate and precise 
temperature control and an integrated timer that controls the duration of cooling, both of which 
facilitate sufficient cooling and prohibit excessive cooling.  Two small protrusions on the tip leave 
temporary indentations on the surface of the eye to guide placement of the intravitreal needle. The 
cooling region of the device is located on a replaceable metal tip. An “ON” switch is first activated to 
cool the contact region of the device, after which this region is placed against the eye, initiating rapid 
cooling to anesthetize the injection site while simultaneously marking the cooled location. After the 
specified cooling time is reached, the device is removed, immediately after which the physician 
performs intravitreal injection.  
 
 
Figure 2 | Cryoanesthesia device.   
 
 
Safety Features: 
 
At maximum power, the device achieves a temperature of -12°C. Any device malfunction 
would result in an increase in this temperature rather than a decrease.   
 
Prior studies as well as our own histological studies with rabbits indicate that this minimum 
cooling temperature (-12°C) is not low enough to cause ocular tissue damage, even with 
extended exposure. For the purpose of the study, the device will not be set to a temperature 
colder than -10°C. 
 
A temperature regulating feedback loop maintains highly accurate and precise temperature 
control, and an integrated timer controls cooling time. 
 
The device tip is replaced with a new sanitized or sterile tip before each use to help ensure 
safe contact with the eye surface. 
 
Device tip indents the eye surface, guiding subsequent needle placement. 
 
Ergonomic and lightweight design, facilitating safe use on or near the eye.  
 
Low operating voltage (11 V). 
 
Prototype Description:  


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The device uses thermoelectric (Peltier) cooling to create the low temperature required for 
cryoanesthesia; thermoelectric cooling has the advantages of being lightweight, small, solid-state (thus 
no fluids or moving parts), and electrically driven (thus allowing straightforward control of 
temperature). The device uses a unique design for efficient heat spreading in which an inner arm made 
from a thermally conductive metal (1 in Fig. 3: cold arm) is simultaneously cooled by a group of 
Peltier modules (2 in Fig. 3) and is thus able to achieve a large cooling power and maintain a low 
temperature at the cooling surface on the replaceable tip (3 in Fig. 3).  This configuration also allows 
the Peltier modules to reject heat to an area of a heat sink (4 in Fig. 3) that is not only large and hence 
efficient but also extended away from the cooling surface, thus allowing a narrow shape with better 
visual clearance during use.  
 
Figure 3 | Device structure. 1–cold arm, 2–Peltier module, 3–replaceable cold tip, 4–heat sink, 5–air 
inlet, 6–air vent, 7–vice-like mechanism, 8–protrusions 
 
Air is received from the inlet openings (5 in Fig. 3) by an electric fan, cools the fins, and exits through 
vents at a location far from the replaceable tip (6 in Fig. 3). The location of the vents far from the 
replaceable tip not only reduces parasitic convection heating at the tip surface but also prevents the 
airflow from drying the eye surface. A rechargeable lithium ion battery pack (28 Wh), which provides 
sufficient energy on a single charge to operate the device at -10˚C for approximately one hour (~100 
treatments), can be easily removed from the rest of the device to facilitate simple charging. 
Temperature control is achieved by an electrical feedback loop that samples the tip temperature using 
a thermal sensor and provides appropriate power to the thermoelectric coolers via pulse width 
modulation (PWM) of the DC battery source. While the cooling surface is unable to reach a 
temperature lower than -12˚C when the device is operated at typical room temperature (20˚C), a 
failsafe automatically powers the device off if the cooling surface falls below -12˚C. Other automatic 
power offs occur if the battery temperature exceeds 60˚C or the heat sink temperature exceeds 50 ˚C.  
A single button on the device is used to set the cold tip temperature and timer duration, as well as 
power the Peltier modules. Operation of the button comprises: 1) Clockwise rotation to increase the 
cold tip temperature setpoint, 2) Counter-clockwise rotation to decrease the cold tip temperature 
setpoint, 3) Clockwise rotation while the button is pushed, to increase the timer duration, 4) Counter-
clockwise rotation while the button is pushed, to decrease the timer duration, and 5) Double-pressing 
to activate the Peltier modules. A second tactile button located near the grip position is used to activate 
(or deactivate) the timer. When the timer is activated, the device produces two consecutive beeping 
sounds at low and high frequencies, followed by beeping sounds every 10 seconds during the timer 
duration, and finally two long consecutive beeping sounds at high and low frequencies when the timer 
1 
3 
2 
4 
5 
6 
7 
8 


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duration has expired. If the “Timer” button is pushed again before the set time is reached, two short 
consecutive beeps at high and low frequencies occur and the timer is immediately terminated.   
 
A user readies the device by first inserting the replaceable tip into the cold arm. A vice-like 
mechanism (7 in Fig. 3) is used to provide both convenient tip replacement and sufficient pressure 
between the replaceable tip and cold arm for good thermal contact. The replaceable tip is coated by a 
thin hydrophobic polymer layer that mitigates ice adhesion between the device and tissue. Two small 
protrusions (8 in Fig. 3) on the replaceable tip leave temporary indentations on the eye surface to guide 
subsequent treatment (e.g., placement of the intravitreal injection needle 3 or 4mm from the corneal 
limbus).  
 
After setting the desired cold tip temperature setpoint and timer duration and inserting the replaceable 
tip, the user operates the device by first double-pressing the main (“rotation & push”) button, which 
turns on the Peltier modules and brings the tip temperature to the setpoint (this takes approximately 20 
seconds for a setpoint of -10˚C). He or she then brings the tip into contact with the patient’s eye and 
presses the “timer” button (which responds with a beep). If the timer duration is set to 10 (or 30) 
seconds, the device maintains -10 ˚C for 10 (or 30) seconds and then beeps. After the timer duration, 
the device returns to ambient temperature.  
 
 There are no anticipated changes to the device during the course of this study.  
 
5.0    Future Studies: 
We plan to conduct a second phase of the study where we will compare the SOC to only one 
cryoanesthesia temperature setpoint and one time setpoint, selected after the analysis of the first 40 
patients. 
 
 
References:  
 
Beckman, H., S. Leff and H. S. Sugar (1975). "Scleral bursting strength. Results after treatment with ruby 
laser, cryotherapy, or diathermy." Arch Ophthalmol 93(6): 428. 
Blaha, G. R., E. P. Tilton, F. C. Barouch and J. L. Marx (2011). "Randomized trial of anesthetic methods for 
intravitreal injections." Retina 31(3): 535-539. 
Chi, H. H. and C. D. Kelman (1967). "Histopathology of corneal endothelium after freezing." Int Ophthalmol 
Clin 7(2): 369-380. 
Curtin, V. T., T. Fujino and E. W. Norton (1966). "Comparative histopathology of cryosurgery and 
photocoagulation. Observations on the advantages of cryosurgery in retinal detachment operations." Arch 
Ophthalmol 75(5): 674-682. 
Davis, M. J., J. S. Pollack and S. Shott (2012). "Comparison of topical anesthetics for intravitreal injections : a 
randomized clinical trial." Retina 32(4): 701-705. 
Friedman, D. S., B. J. O'Colmain, B. Munoz, S. C. Tomany, C. McCarty, P. T. de Jong, B. Nemesure, P. 
Mitchell, J. Kempen and G. Eye Diseases Prevalence Research (2004). "Prevalence of age-related macular 
degeneration in the United States." Arch Ophthalmol 122(4): 564-572. 
Garamy, G. (1967). "Engineering aspects of cryosurgical instruments employing liquid nitrogen." Int 
Ophthalmol Clin 7(2): 283-308. 
Lee, S. J., S. Choi, M. S. Kim, Y. Cheong, H. W. Kwak, H. K. Park and K. H. Jin (2013). "Short-term effect of 
cryotherapy on human scleral tissue by atomic force microscopy." Scanning 35(5): 302-307. 
Lindsell, L. B., D. M. Miller and J. L. Brown (2014). "Use of topical ice for local anesthesia for intravitreal 
injections." JAMA Ophthalmol 132(8): 1010-1011. 


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Maumenee, A. E. and W. Kornblueth (1949). "Regeneration of the corneal stroma cells; review of literature 
and histologic study." Am J Ophthalmol 32(8): 1051-1064. 
Sanabria, M. R., J. A. Montero, M. V. Losada, M. Fernandez-Munoz, A. Galindo, I. Fernandez, R. M. Coco 
and A. Sampedro (2013). "Ocular pain after intravitreal injection." Curr Eye Res 38(2): 278-282. 
Xing, L., S. J. Dorrepaal and J. Gale (2014). "Survey of intravitreal injection techniques and treatment 
protocols among retina specialists in Canada." Can J Ophthalmol 49(3): 261-266.