1
A Comparison of Wound Strength with and without
Hydrogel Liquid Ocular Bandage in Human Cadaver
Eyes

• Surekha Maddula, M.D., Don K. Davis, M.D., Peter
  J. Ness, M.D., Randall J. Olson, M.D.
• Department of Ophthalmology and Visual Sciences,
  John A. Moran Eye Center, University of Utah,
  Salt Lake City, Utah

This study was supported in part by an
unrestricted grant from Becton, Dickinson and
Company, Waltham, MA, USA and by
an unrestricted grant from Research to Prevent
Blindness, Inc., New York, NY, to the Department
of Ophthalmology Visual Sciences, University of
Utah. Dr. Olson is a consultant to Becton,
Dickinson and Company.
2
Introduction

• The advancements in microsurgery and
  disadvantages of sutures has shifted toward
  sutureless surgery in clear corneal incisions and
  pars plana vitrectomy procedures
• However, sutureless incisions are more likely
  than sutured incisions to leak after surgery, and
  a leaky wound is a potential source for bacterial
  endophthalmitis1,2
• Studies show that post operative leaking and
  sutureless surgery is associated with
  endophthalmitis due to ingress and egress of
  ocular fluids from changing ocular pressure2-5

3
Introduction

• Adhesive sealants on corneal or scleral wounds
  may be a solution to early post-operative
  incision leakage
• Polyethylene glycol (PEG) hydrogels are synthetic
  materials that may have advantages over
  biological materials.
• Hydrogel liquid ocular bandages are safe
• Comfortable
• Easy and quick to apply
• Persist on for several days
• Protect the wound
• Enhance wound strength

4
Objective

• The purpose of this study is to determine whether
  a hydrogel liquid ocular bandage is efficacious
  in improving wound strength.

5
Materials and Methods

• 5 cadaver eyes were obtained from Lions Eye Bank
  to test a total of 20 23-gauge incisions and 20
  clear corneal incisions
• In each eye a 23-gauge pars plana vitrectomy with
  Alcon Infinity was performed to remove vitreous
  that may potentially block incisions
• Pars plana incisions were created with 23-gauge
  MVR blades then tested for wound bursting
  strength by increasing bottle height of BSS
  connected to the optic nerve via 23-gauge needle.
  
• Each incision was tested with and without
  hydrogel liquid bandage, Ocuseal and then sealed
  with cyanoacrylate for a total of 4 pars plana
  incisions in each eye
• A clear corneal incision was then made with a
  2.8mm angled steel blade and the iris was
  removed, lens dislocated posteriorly and needle
  in optic nerve advanced into the anterior chamber
• Each clear corneal incision was then tested with
  and without Ocuseal and then sealed with
  cyanoacrylate for a total of 4 clear corneal
  incisions in each eye

6
Results
  23 Gauge Incisions 23 Gauge Incisions Clear Corneal Incisions Clear Corneal Incisions
  Bursting Pressure w/o ocuseal (mmHg) Bursting Pressure with ocuseal (mmHg) Bursting Pressure w/o ocuseal (mmHg) Bursting Pressure with ocuseal(mmHg)
Cadaver Eye 1        
Incision 1 18.6 246.2 (no burst) 37.2 100.7
Incision 2 14.9 246.2 (no burst) 44.7 110
Incision 3 35.4 212.6 35.4 89.5
Incision 4 44.7 210.7 18.6 96.9
Cadaver Eye 2        
Incision 1 87.7 246.2 (no burst) 93.2 169.7
Incision 2 44.8 246.2 (no burst) 67.1 175.3
Incision 3 55.9 246.2 (no burst) 70.9 246.2 (no burst)
Incision 4 50.4 246.2 (no burst) 95.1 194
Cadaver Eye 3        
Incision 1 65.3 179 41 233.1
Incision 2 76.5 167.8 55.9 195.8
Incision 3 70.9 158.52 52.1 246.2 (no burst)
Incision 4 76.5 160.4 44.7 246.2 (no burst)
Cadaver Eye 4        
Incision 1 57.8 231.3 67.1 246.2 (no burst)
Incision 2 37.3 18.6 52.2 246.2 (no burst)
Incision 3 46.6 235 52.2 171.6
Incision 4 69 246.2 (no burst) 67.1 214.5
Cadaver Eye 5        
Incision 1 28 190.2 57.8 240.6
Incision 2 26.1 186.5 102.6 246.2 (no burst)
Incision 3 26.1 246.2 (no burst) 67.1 246.2 (no burst)
Incision 4 26.1 91.4 67.1 246.2 (no burst)
7
Results

• Mean Leakage pressure was determined and compared
  using a student T-test.
• For non-parametric testing a Chi-square analysis
  was used.
• With four comparisons, significance with a
  Bonferroni correction for multiple comparisons
  was set at Plt.012

8
Results
2.8 mm Corneal Incisions 23-Gauge Scleral Incisions
Mean Leakage without liquid ocular bandage 59.5 /-21.0mmHg 47.9/-21.4mmHg
Mean Leakage with liquid ocular bandage 198.1/-57.6mmHg 200.6/-60.4mmHg
P value for above two comparisons Plt.0001 P lt .0001
Number of Incisions without leakage at maximal pressure without bandage 0 out of 20 0 out of 20
Number of Incisions without leakage at maximal pressure with bandage 8 out of 20 7 out of 20
P value for above two comparisons P .009 P .014
Table. Intraocular pressure at which incision
leakage was noted for both 23-gauge scleral and
2.8 mm limbal incisions in human cadaver eyes,
both with and without use of a hydrogel liquid
bandage formulated for ocular use. Our maximal
attainable intraocular pressure was 246mmHg, the
figure which we used when the incision did not
leak at this pressure. We also compare the number
of incisions that did not leak at our maximal
attainable pressure of 246mmHg.
9
Discussion

• The goal of an ocular bandage is to protect
  injured tissue, and to help the reemergence of a
  normal anatomic and functional state of the
  ocular incision through wound remodeling and
  repair.
• Advantages to synthetic hydrogel sealants over
  fibrin and cyanoacrylate alternatives
• Quick and easy to prepare and use
• Can be applied at neutral pH1
• Require no external energy source
• Safe and tolerable in the eye, non-toxic and no
  antigenicity or immune response6
• 85 water content after application has physical
  properties comparable to tissue, and suitable to
  fill in irregularities and conform to the normal
  architecture
• Polymerization after application takes
  approximately
• 45 seconds to achieve maximal strength
• Watertight and flexible that cornea can resist
• egress and ingress of ocular surface
• contaminants by 92 over incisions
• without such a bandage7
• Removal is not an issue as it breaks down
• under physiological conditions and
  degradation
• products are water soluble and cleared
  through body

10
Conclusions

• Postoperative hypotony and fluctuations in
  intraocular pressure secondary to incision
  leakage is a concern8-10
• Pressure changes in the eye are consequences of a
  faulty incision and can cause egress of the
  contaminated tear film into the eye, potentially
  leading to endophthalmitis
• A hydrogel liquid bandage has the potential
  advantage of easy and quick application, is well
  tolerated, and resists incision distortion due to
  its malleable nature
• Our results showed that the hydrophilic acrylic
  hydrogel PEG bandage is statistically significant
  for resistance to wound leakage at very high
  intraocular pressures for both 2.8mm corneal
  incisions and 23-gauge scleral incisions.
• Application of hydrogel liquid ocular bandage
  allows for substantially higher intraocular
  pressures before leakage when compared to the
  native wound and we suggest its use in the early
  postoperative period for procedures using
  sutureless incisions.

11
References

• 1. Grinstaff MW. Designing hydrogel adhesives for
  corneal wound repair. Biomaterials 2007
  285205-5214
• 2. Nagaki Y, Hayasaka S, Kadoi C, Matsumoto M,
  Yanagisawa S, Watanabe K, et al. Bacterial
  endophthalmitis after small-incision cataract
  surgery. effect of incision placement and
  intraocular lens type. J Cataract Refract Surg
  2003 2920-26
• 3. Results of the Endophthalmitis Vitrectomy
  Study. A randomized trial of immediate vitrectomy
  and of intravenous antibiotics for the treatment
  of postoperative bacterial endophthalmitis.
  Endophthalmitis Vitrectomy Study Group. Arch
  Ophthalmol 1995 1131479-1496
• 4. Wallin T, Parker J, Jin Y, Kefalopoulos G,
  Olson RJ. Cohort study of 27 cases of
  endophthalmitis at a single institution. J
  Cataract Refract Surg 2005 31735-741
• 5. Kunimoto DY, Kaiser RS. Incidence of
  endophthalmitis after 20- and 25-gauge
  vitrectomy. Ophthalmology 2007 1142133-2137
• 6. Kim T, Kharod BV. Tissue adhesives in corneal
  cataract incisions. Curr Opin Ophthalmol 2007
  1839-43
• 7. Hovanesian JA. Cataract wound closure with a
  polymerizing liquid hydrogel ocular bandage. J
  Cataract Refract Surg 2009 35912-916
• 8. Irak-Dersu I, Nilson C, Zabriskie N, Durcan J,
  Spencer HJ, Crandall A. Intraocular pressure
  change after temporal clear corneal
  phacoemulsification in normal eyes. Acta
  Ophthalmol 2009 Epub ahead of print
• 9. Schwenn O, Dick HB, Krummenauer F, Krist R,
  Pfeiffer N. Intraocular pressure after small
  incision cataract surgery temporal sclerocorneal
  versus clear corneal incision. J Cataract Refract
  Surg 2001 27421-425
• 10. Gupta OP, Ho AC, Kaiser PK, Regillo CD, Chen
  S, Dyer DS, et al. Short-term outcomes of
  23-gauge pars plana vitrectomy. Am J Ophthalmol
  2008 146193-197