Microincisions in Cataract Surgery
Tal Raviv, MD
Techniques of Incision Creation
The temporal clear corneal incision is the most commonly employed incision in modern
cataract surgery. The incision has many advantages over its predecessor superior scleral
incisions, but continues to be perfected with greater understanding of the dynamic architecture
and with emerging technologies such as femtosecond laser.
The benefits of today’s cataract incision are many including: its efficient creation, lack of
conjunctival trauma, bloodless operative field, applicability to topical anesthesia, allowance for
good intraoperative maneuverability, sutureless self-sealing nature, minimal induction of
astigmatism, and allowance for extremely rapid visual recovery. Though some problems
remain, such as lack of consistency and reproducibility, incompetence under certain intraocular
pressure extremes, risk of bacterial breaching and endophthalmitis, and vulnerability to
mechanical or thermal damage from phacoemulsification and lens insertion.
Architecture
Incisions can be created either uni-planar, bi-planar, or tri-planar. While surgeons each have
their preferences, studies[Ernest 1995][Fine 2007][May 2010] show that generally bi- or triplaned incisions have more integrity than single plane incisions. By incorporating both vertical
and horizontal elements, multiplane incisions are best able resist breach under pressure
extremes. Some authors have advocated square incisions [Ernest 1994][Masket 2007] as
having particular strength over more rectangular incisions. Finally, longer tunnel lengths (i.e.
2.0mm over 1.0mm are also more resistant to leakage [Masket 2010]. Though when too long,
they can cause corneal striae and distortion during surgery.
Location
As for location, the historical transition from superior scleral to temporal corneal took place for
multiple reasons including conjunctival sparing and increased efficiency. Comparing scleral to
corneal locations, scleral incisions are stronger and more self-sealing under longer lengths than
corneal incisions. They are also more forgiving to stretch and damage. Scleral incisions produce
less astigmatism (for constant size) by virtue of their further distance from the visual axis.
Finally, scleral incisions have been shown [Beltrame 2001] to cause less endothelial trauma,
likely due to their distal location away from the endothelium. However scleral incision require
more surgical time, conjunctival dissection, hemostasis, and increased anesthesia.
Surgeons have tried to optimize the efficiency of the corneal incision with the perceived safety
of scleral incisions with posterior limbal[Ernest 1996], sclerocorneal [Tsuneoka 1999], and blueline incisions [Buzard 1999]. While posterior limbal incisions produced an earlier fibroblastic
healing response than clear corneal incisions [Ernest 1998], they were also associated with
more bleeding and perhaps more intraocular inflammation [Dick 1999].
The axis of the incision while most commonly placed temporally for traditional coaxial
phacoemulsification, can be placed in any location. The primary differences in choice of
incision axis relates to astigmatism and accessibility. The temporal cornea affords advantages
in both accessibility and its minimal astigmatic effect [Barequet 2004] compared to incisions at
other locations, likely due to the longer horizontal corneal diameter. Most clear corneal
surgeons operate either temporally for consistency and astigmatic neutrality or on the steep
axis in order to affect the final refractive outcome.
Material: Steel vs Diamond
The blade used in cataract surgery has evolved historically. Stainless steel blades were common
in most of surgery and the steel von Graefe knife was one of the most famous in the evolution
of cataract surgery. The first published study [Durham 1968] of the use of a diamond knife in
cataract surgery was in 1968. In fact, it was the first use of a diamond knife in any human
surgery at the time. Subsequent scanning electron microscopy studies have shown diamond
blades to produce cleaner cuts on a cellular level than steel [Marshall 1986][Radner
1998][Jacobi 1998]. A single use silicon blade material was also found to be smoother than steel
on electron microscopy [Etter 2009]
Most surgeons today use either a reusable diamond blade or a disposable steel keratome.
Diamond blade advocates enjoy the exceptionally clean incisions, while keratome aficionados
prefer the tactile feedback and perceived control with steel. Disposable blades are affordable,
frequently bundled in phaco packs, easily interchangeable for different incision sizes, and avoid
sterility issues; diamond blades are expensive, require maintenance, and have theoretical prion
and TASS risk. While no direct studies compare the wound integrities of diamond vs. steel, most
authors agree that the final achieved wound architecture is more important than the material
used.
Blades themselves come in different bevels, angulations, steps and shapes with surgeons each
having a favorite. No studies directly compare the benefits of these blade characteristics to
each other, however Calladine [Calladine 2010] did report more reproducible length and planar
architecture by using a blade that had an incision-length measuring guide
Femtosecond
As femtosecond laser cataract surgery emerges [Masket 2010] and matures, we will continue to
hone our cataract incisions as we have our LASIK flaps. The femtosecond laser will allow us to
shape the length, angles, planes, and shapes of our incisions reproducibly to levels never before
achieved. We will be able to flare [Osher 2012] the incision internally to decrease oar-locking
and engineer a more consistently self-sealing incision.
Evaluating the Wound
Creating the cataract incision is one thing, but effectively evaluating the wound both
qualitatively and quantitatively afterwards is another. Wound integrity testing after clear
cornea cataract surgery is critical due to the association of corneal incisions and
endophthalmitis [Packer 2011].
Until recent advances in imaging, only straightforward assessments of the cataract wound were
available. At the conclusion of surgery, surgeons could visually inspect the wound for damage
or incompetence, grossly evaluate its ability to maintain the anterior chamber, and detect
smaller aqueous leaks with Seidel testing [Cain 1981]. Beyond passive testing, surgeons could
check for dynamic leakage by applying pressure adjacent to the wound, to both increase IOP
and create wound deformation [May 2010]. The surgeon would then take appropriate actions
to ensure adequate closure was achieved by employing one, or a combination of, stromal
hydration, suturing, or experimentally -- a wound adhesive.
With the advent of the anterior segment Optical coherence tomography (OCT) and use of India
Ink particle flow studies, more light has been shed on the integrity of the cataract incision and
different modalities to seal it.
Static Wound evaluation
Imaging of the cataract wound’s architecture in the living eye (in vivo) was described by Fine
[Fine 2007] who used anterior segment OCT to study incisions on postoperative day one. One
of the surprising findings were the incisions’ arcuate profile – not the straight planar design
conceived. Calladine [Calladine 2007] further described the five classic OCT features of the clear
corneal incision: endothelial or epithelial gaping, loss of coaptation, endothelial misalignment,
and local Descemet’s detachment. At least one, and sometimes all five [Calladine 2010] of
these findings was seen in nearly all the incisions. With coaptation a clear passage of fluid
connected the intraocular and extraocular space.
OCT imaging studies also highlighted the discrepancy between surgeon’s intended incision
design and measurements versus achieved. While the five surgeons in Calladine’s study
attempted to execute a tri-planar incision, OCT imaging revealed only one third to have this
architecture, with two thirds being bi-planar, and one case uni-planar. OCT imaging also
revealed the wide range of achieved incision lengths versus attempted. In Calladine’s study,
the incision length varied greatly from 1.1 to 2.25 mm. Schallhorn [Schallhorn 2008] similarly
showed a wide range of incision lengths from 1.41 to 2.39mm despite the surgeons’ intended
2mm.
Newer fourier-domain OCT studies [Calladine 2010] [Li Wang 2012] and 3D OCT studies
revealed even more imaging detail. Li Wang found long term wound remodeling changes such
as late posterior wound retraction. The clinical significance of this is unknown, but emerged at
2 to 3 week post-op and was present in 75% of all eyes by 3 year postop.
Weikert [Weikert 2012] evaluated the microincision quantitatively using scanning electron
microscopy and showed that both the exterior and internal corneal surface showed no major
changes after incision creation, but that following phaco, micro descemet’s tears and areas of
endothelial cell loss were present in every case.
Dynamic Wound evaluation
Beyond the static wound morphology, characterizing what occurred through the incision in real
life scenarios proved critical. While the Seidel test for wound integrity had stood the test of
time, the seeming rise of endophthalmitis rates along with the popularization of the clear
corneal incision led to closer evaluation of the wound’s integrity.
Dynamic changes in wound architecture and fluid flow were evaluated by McDonnell
[McDonnell 2003] using OCT imaging and India Ink as a surrogate for bacterial contamination.
By varying IOPs in eye bank eyes, McDonnell demonstrated that while IOPs up to 50mmHg
didn’t cause loss of wound integrity or leakage, reduction of IOP to the 5-10mmHg range did
cause India Ink ingress and visible gaping of the wounds on OCT. This study formed the basis
for using India Ink, an opaque fluid with particle size similar to bacteria, as a model for ocular
surface fluid penetration in endophthalmitis. It also put the subjective Seidel test into question,
as even a negative Seidel was associated with India Ink inflow after sudden changes in IOP [May
2010}
Ocular hypotony became the potential culprit in contaminated conjunctival fluid imbibition
through gaping wounds. Since Shingleton [Shingleton 12], had showed that early postoperative
hypotony below 5mmHg was relatively common in the early postoperative period, further
studies of wound behavior under hypotony ensued.
Taban[Taban 2004] found that the angle of the incision influenced its integrity in different IOP
ranges. More horizontal (parallel to the corneal surface) incisions resisted higher IOP better, but
had more gaping with lower IOP, while more vertical (perpendicular to the corneal surface)
incisions sealed less well under high pressure, but had greater apposition under low pressure.
Sarayba further demonstrated India ink influx into seemingly self-sealing wounds after manual
pressure was applied to the corneal surface -- to stimulate eye rubbing or forceful blinking. The
authors observed India Ink influx in the brief period of relative hypotony after release of manual
pressure – denoting a vacuum effect.
While the above cadaver models perhaps lacked a fully functioning endothelial pump, other in
vivo evidence of hypotony induced fluid influx were seen with blood [Herretes 2005],
fluorescein[Chawdhary 2006], and trypan blue [Praveen2008]. This mounting evidence even
led to graphic descriptions of “the sucking corneal wound” [Francis 2009].
To see if specific wound architecture provided better integrity, May examined wounds of
different morphology to see which would be most resistant to influx of external ocular fluid.
Using the India ink experimental settings described above[May 2008], the author showed that
3mm incisions were better than 1.0mm long incisions and bi-planar incisions were superior to
single step incisions in preventing inflow during periods of hypotony or sudden changes in IOP.
May concluded that wound construction that incorporated vertical and horizontal components
was the most effective in preventing bacterial influx – as it was resistant to both low and high
pressure deformation.
Treating the Incompetent Wound
While well-crafted, tri-planar, square, corneal incisions may be self-sealing in most cases, there
are instances where they may be less so and further security may be warranted. This may be
due to error in initial wound creation, such as premature blade entry with a short tunnel or
secondary to damage sustained during cataract removal and lens implantation.
Stromal Hydration
Stromal hydration is commonly employed by surgeons to help seal the corneal incision at the
conclusion of phaco. First the eye is filled to physiologic pressure with balanced salt solution to
close the posterior lip/valve mechanism of the wound. Then, the external wound is dried with
a sponge and observed for intra-ocular fluid leakage. If spontaneous leakage is present, the
surgeon can forcefully inject saline into the lateral and superior stromal walls of the incision
until whitening of the cornea is observed.
Clinically, most cataract surgeons have experienced the wound sealing benefit of stromal
hydration; it is almost universally effective in stopping wound leakage at the conclusion of
surgery. But controversy has arisen to its role, with critics pointing to its short lasting effect and
its possible distortion of the wound. Most importantly, does it protect from hypotony induced
inflow of contaminated ocular fluid in the immediate postoperative period.
Published studies have given us some insight. Mifflin [Mifflin 2012] showed that greater than
50% of incisions leaked pre-hydration, but none leaked post-hydration. In another stromal
hydration study, Calladine [Calladine 2009] found higher IOPs one hour post-operatively in the
stromal hydration group vs the control, likely due to less early micro- leakage. These higher
IOPs may protect from early postoperative hypotony and its potential vacuum effect.
Furthermore, Vasavada [Vasavada 2007] demonstrated that the ingress of Trypan-blue was
decreased several-fold by stromal hydration. Nevertheless, inflow of surface fluid has been
described even despite stromal hydration [Herretes 2005].
Early opponents of stromal hydration argued that the effect only lasted hours. But initial OCT
imaging studies [Fine 2007] showed stromal hydration to be present at least 24 hours after
surgery. More recent, higher resolution fourier domain OCT imaging found the effect lasted for
at least one week after surgery [Fukuda 2011]. These OCT studies also showed distortion of the
original wound architecture and an increase in descemet’s detachment in the stromal hydration
group – leading some to question [Walters 2011] the benefit of stromal hydration in the future
era of “touchless” minimally invasive surgery.
A variation of traditional stromal hydration using a secondarily constructed anterior stromal
pocket was found to be even more efficacious than conventional hydration with the application
of external pressure to the wound [Mifflin 2012]. OCT imaging of this ‘Wong’ pocket
demonstrates posterior compression of the internal lip presumably creating greater wound
apposition.
While stromal hydration is the standard of care today, further study is required to elucidate its
role in incision closure. If the wound’s integrity is in question before or after stromal hydration,
suture closure is the surgeon’s next option.
Sutures
Sutures have been the gold standard to achieve secure wound closure due to their historical
use in large incision cataract surgery. In clinical use, sutures have been used to seal ophthalmic
wounds for decades. Besides the obvious immediate effect of wound closure, many advocated
suturing of corneal incisions to minimize the slowly rising endophthalmitis rates observed with
transition to suture-less clear cornea surgery.
The literature is mixed on suture’s role. While some studies suggest that sutured [Thoms 2007]
corneal incisions were protective of endophthalmitis, others[Ng 2007] found no such protective
benefit from suture placement.
OCT imaging showed no architectural difference between sutured and unsutured wounds in the
one day to one month postoperative period [Li Wang2012]. But, surprisingly, May[May 2011]
showed convincingly that sutured corneal incisions had more India Ink influx than unsutured
incisions under sudden IOP fluctuations. The author observed[May 2012] that a single radial 100 nylon suture increased inner wound gaping on OCT and conjectured that the suture tract
itself contributed to potential infiltration.
In addition, sutures have the associated problems of increased surgical time, inconsistent effect
on astigmatism, and the need to be removed with a secondary procedure (in the case of nonbiodegradable material). Sutures that are left in place have been reported to induce
neovascularization, suture breakage, and suture abscess.
The standard of care remains to place a suture to stem leakage if stromal hydration is
ineffective or if gross wound distortion is present, but routine suture placement for theoretical
endophthalmitis prevention is not merited in the literature.
Tissue Adhesives
Tissue adhesives have recently been investigated for securing the cataract incision. Sutures
have been the gold standard historically but are imperfect. Could incisions be made even more
watertight with an adhesive sealant? This would benefit the incompetent wound not only
from grossly leaking, but by capturing micro-leaks in seemingly competent wounds – ensure
greater chamber stability for accommodative or toric IOLs and prevent endophtalmitis.
The ideal ocular adhesive or sealant would create a watertight seal to prevent influx of
potentially contaminated extra-ocular fluid during hypotony or leaks of aqueous during
moments of high IOP such as eye rubbing or forced blinking. It would be non-toxic, easy to
apply, incite no inflammation, produce no foreign body sensation or hyperemia, be
biodegradable, enhance wound healing and be optically clear.
For many years, cyanoacrylate and fibrin glue have been used off label in ophthalmology for
specific indications. Cyanoacrylates are used in corneal perforation or impending perforation,
while fibrin glue is commonly used for conjunctival and amniotic membrane transplantation.
However on the cornea, cyanoacrylate glue tends to be brittle, cause foreign body sensation,
and require a bandage contact lens. The more elastic 2-octyl cyanoacrylate (Liquid Bandage)
has been used in vivo [Meskin 2005] for sealing the cataract wound, but again foreign body
sensation and hyperemia were common.
Fibrin adhesive was investigated [Hovanesian 2007] in eye-bank clear corneal incisions and
found to prevent ingress of India ink and egress of fluid compared to placebo. Fibrin adhesives
though are more difficult to prepare, have a high cost, have the inherent transmission risks of
pooled plasma, and are have not been studied for intra-ocular toxicity.
As for the tensile strength of these adhesives compared to sutures, Bannitt et al [Bannitt 2009]
showed that the mean IOP required for leakage was lowest for sutures, followed by fibrin
adhesive, and best with n-butyl-2-cyanoacrylate. Kaja et al [Kaja 2012] also demonstrated that
wounds sealed with n-butyl-2-cyanoacrylalte had a significantly higher leakage IOP compared to
sutures (120mmHg vs 84Hg in Bovine eyes and 140mmHg to 76mmHg in Porcine eyes)
Several other novel adhesives are experimentally being evaluated for sealing the corneal
incision. They range from biologic to synthetic to combinations or bio-synthetics. In addition,
corneal soldering [-Noguera 2007] and tissue welding [Menabuoni 2007] have been described.
Experimentally, soldering and welding were shown to be as strong or in some cases stronger
than sutures; both are complicated by requiring activation with a laser and may induce
astigmatism.
Of the other experimental adhesives, biodendrimers are synthetics that either photo-activate
with an argon laser [Degoricija 2007] or self-polymerize into a hydrogel sealant. A donor eye
study [Johnson 2009], showed a substantial increase in leaking pressures from 77mmHg for
unsealed wounds to 142mmHg with biodendrimer adhesive-sealed wounds. Similarly, the
strongly adherent hydrogel polymer prevented influx of India ink particles during IOP
fluctuations. These effects were visualized on OCT, where the homogeneous sealant was able
to flex and prevent leakage despite wound gape during IOP fluctuations. An in vivo histological
comparison [Berdahl 2009] of the biodendrimer adhesive to sutures found decreased long term
corneal scarring with the glued corneas.
The other large class of ophthalmic sealant is based on Polyethylene glycol (PEG) hydrogel
polymers (familiar to most ophhthalmologist as a component of artificial tears such as Systane,
Alcon). The adhesives are either polysaccharide-attached bio-synthetics [Bhatia 2007] such as
chondroitin sulfate-PEG [Strehin 2009] and dextran aldehyde-PEG[Chenault 2011] or pure
synthetic PEG polymers. All these PEG based adhesives have been shown to be non-toxic,
strongly bonding, and possess high burst pressures.
There are at least two commercially available PEG formulations available outside the United
States for wound closure: OcuSeal® Liquid Ocular Bandage (Beaver Visitec) and ReSure®
Adherent Ocular Bandage (Ocular Therapeutix). These synthetic PEG polymers (comprised
mostly of PEG and water) have a long track record of use in biomaterials and were engineered
for setting time, firmness, and durability. They are applied as a liquid and form a gel over the
incision in 30-45 seconds.
Eye bank eye studies have shown the PEG ocular bandages ReSure [Hovanesian 2009] and
OcuSeal [Maddula] to be watertight and highly effective in preventing ingress or egress of fluid
through the incision under supra-physiological IOP fluctuations. A highly detailed fourierdomain anterior segment OCT study [Calladine 2010] elegantly showed how the hydrogel
sealant strongly adheres to the wound edges where it provides a smooth protective barrier.
Even with wound deformation and gape, the hydrogel remains intact and can be visualized to
contain microleaks. The bandages acted as a pseudoepithelium and were replaced by healing
epithelium over the days and weeks postoperatively.
Conclusion
Our understanding of corneal incision structure and function continues to improve. Through
high resolution SEM imaging, fourier-domain anterior segment OCT, and India ink dynamic
studies, we strive closer to the goal of the perfect wound. With the more reproducible and
highly customizable wound designs afforded by femtosecond incisions and with novel corneal
sealants cataract surgery safety will rise even higher for our patients.
References:
Anders, N, D T Pham, H J Antoni, and J Wollensak. “Postoperative Astigmatism and Relative Strength of
Tunnel Incisions: a Prospective Clinical Trial.” Journal of Cataract and Refractive Surgery 23, no. 3 (April
1997): 332–336.
Banitt, Michael, João Baptista Malta, H Kaz Soong, David C Musch, and Shahzad I Mian. “Wound
Integrity of Clear Corneal Incisions Closed with Fibrin and N-butyl-2-cyanoacrylate Adhesives.” Current
Eye Research 34, no. 8 (August 2009): 706–710.
Barequet, Irina S, Edward Yu, Susan Vitale, Sandi Cassard, Dimitri T Azar, and Walter J Stark.
“Astigmatism Outcomes of Horizontal Temporal Versus Nasal Clear Corneal Incision Cataract Surgery.”
Journal of Cataract and Refractive Surgery 30, no. 2 (February 2004): 418–423.
Beltrame, G, M L Salvetat, M Chizzolini, and G Driussi. “Corneal Topographic Changes Induced by
Different Oblique Cataract Incisions.” Journal of Cataract and Refractive Surgery 27, no. 5 (May 2001):
720–727.
Beltrame, Giorgio, Maria L Salvetat, Giobatta Driussi, and Marzio Chizzolini. “Effect of Incision Size and
Site on Corneal Endothelial Changes in Cataract Surgery.” Journal of Cataract and Refractive Surgery 28,
no. 1 (January 2002): 118–125.
Berdahl, John P, John J DeStafeno, and Terry Kim. “Corneal Wound Architecture and Integrity After
Phacoemulsification Evaluation of Coaxial, Microincision Coaxial, and Microincision Bimanual
Techniques.” Journal of Cataract and Refractive Surgery 33, no. 3 (March 2007): 510–515.
Berdahl, John P, C Stark Johnson, Alan D Proia, Mark W Grinstaff, and Terry Kim. “Comparison of Sutures
and Dendritic Polymer Adhesives for Corneal Laceration Repair in an in Vivo Chicken Model.” Archives of
Ophthalmology 127, no. 4 (April 2009): 442–447.
Berdahl, John P, Bokkwan Jun, John J DeStafeno, and Terry Kim. “Comparison of a Torsional Handpiece
Through Microincision Versus Standard Clear Corneal Cataract Wounds.” Journal of Cataract and
Refractive Surgery 34, no. 12 (December 2008): 2091–2095.
Bhatia, Sujata K, Samuel D Arthur, H Keith Chenault, Garret D Figuly, and George K Kodokian.
“Polysaccharide-based Tissue Adhesives for Sealing Corneal Incisions.” Current Eye Research 32, no. 12
(December 2007): 1045–1050.
Buzard, K A, and J L Febbraro. “Transconjunctival Corneoscleral Tunnel ‘Blue Line’ Cataract Incision.”
Journal of Cataract and Refractive Surgery 26, no. 2 (February 2000): 242–249.
Cain, W, Jr, and R M Sinskey. “Detection of Anterior Chamber Leakage with Seidel’s Test.” Archives of
Ophthalmology 99, no. 11 (November 1981): 2013.
Calladine, Daniel. “Optical Coherence Tomography Studies of Clear Corneal Incision Wound
Architecture.” Journal of Cataract and Refractive Surgery 37, no. 7 (July 2011): 1375; author reply 1375–
1376.
Calladine, Daniel, and Richard Packard. “Clear Corneal Incision Architecture in the Immediate
Postoperative Period Evaluated Using Optical Coherence Tomography.” Journal of Cataract and
Refractive Surgery 33, no. 8 (August 2007): 1429–1435.
Calladine, Daniel, and Vaughan Tanner. “Optical Coherence Tomography of the Effects of Stromal
Hydration on Clear Corneal Incision Architecture.” Journal of Cataract and Refractive Surgery 35, no. 8
(August 2009): 1367–1371.
Calladine, Daniel, Mina Ward, and Richard Packard. “Adherent Ocular Bandage for Clear Corneal
Incisions Used in Cataract Surgery.” Journal of Cataract and Refractive Surgery 36, no. 11 (November
2010): 1839–1848.
Can, Izzet, Hasan Ali Bayhan, Hale Celik, and Başak Bostancı Ceran. “Anterior Segment Optical Coherence
Tomography Evaluation and Comparison of Main Clear Corneal Incisions in Microcoaxial and Biaxial
Cataract Surgery.” Journal of Cataract and Refractive Surgery 37, no. 3 (March 2011): 490–500.
Cavallini, Gian Maria, Luca Campi, Giulio Torlai, Matteo Forlini, and Elisa Fornasari. “Clear Corneal
Incisions in Bimanual Microincision Cataract Surgery: Long-term Wound-healing Architecture.” Journal
of Cataract and Refractive Surgery 38, no. 10 (October 2012): 1743–1748.
Chawdhary, Satish, and Aashish Anand. “Early Post-phacoemulsification Hypotony as a Risk Factor for
Intraocular Contamination: In Vivo Model.” Journal of Cataract and Refractive Surgery 32, no. 4 (April
2006): 609–613.
Chen, Wei-Li, Chung-Tien Lin, Chia-Yun Hsieh, I-Hua Tu, Willie Y W Chen, and Fung-Rong Hu.
“Comparison of the Bacteriostatic Effects, Corneal Cytotoxicity, and the Ability to Seal Corneal Incisions
Among Three Different Tissue Adhesives.” Cornea 26, no. 10 (December 2007): 1228–1234.
Chenault, H Keith, Sujata K Bhatia, William G Dimaio, Grant L Vincent, Walter Camacho, and Ashley
Behrens. “Sealing and Healing of Clear Corneal Incisions with an Improved Dextran aldehyde-PEG Amine
Tissue Adhesive.” Current Eye Research 36, no. 11 (November 2011): 997–1004.
Degoricija, Lovorka, C Starck Johnson, Michel Wathier, Terry Kim, and Mark W Grinstaff. “Photo Crosslinkable Biodendrimers as Ophthalmic Adhesives for Central Lacerations and Penetrating
Keratoplasties.” Investigative Ophthalmology & Visual Science 48, no. 5 (May 2007): 2037–2042.
Dick, H B, O Schwenn, F Krummenauer, R Krist, and N Pfeiffer. “Inflammation After Sclerocorneal Versus
Clear Corneal Tunnel Phacoemulsification.” Ophthalmology 107, no. 2 (February 2000): 241–247.
Dupont-Monod, Sylvère, Antoine Labbé, Nicolas Fayol, Alexis Chassignol, Jean-Louis Bourges, and
Christophe Baudouin. “In Vivo Architectural Analysis of Clear Corneal Incisions Using Anterior Segment
Optical Coherence Tomography.” Journal of Cataract and Refractive Surgery 35, no. 3 (March 2009):
444–450.
Durham, D G, and M H Luntz. “Diamond Knife in Cataract Surgery.” The British Journal of Ophthalmology
52, no. 2 (February 1968): 206–209.
Elkady, Bassam, David Piñero, and Jorge L Alió. “Corneal Incision Quality: Microincision Cataract Surgery
Versus Microcoaxial Phacoemulsification.” Journal of Cataract and Refractive Surgery 35, no. 3 (March
2009): 466–474.
Ernest, P H, R Fenzl, K T Lavery, and A Sensoli. “Relative Stability of Clear Corneal Incisions in a Cadaver
Eye Model.” Journal of Cataract and Refractive Surgery 21, no. 1 (January 1995): 39–42.
Ernest, P H, K T Lavery, and L A Kiessling. “Relative Strength of Scleral Corneal and Clear Corneal Incisions
Constructed in Cadaver Eyes.” Journal of Cataract and Refractive Surgery 20, no. 6 (November 1994):
626–629.
Ernest, P H, and T Neuhann. “Posterior Limbal Incision.” Journal of Cataract and Refractive Surgery 22,
no. 1 (February 1996): 78–84.
Ernest, P, R Tipperman, R Eagle, C Kardasis, K Lavery, A Sensoli, and M Rhem. “Is There a Difference in
Incision Healing Based on Location?” Journal of Cataract and Refractive Surgery 24, no. 4 (April 1998):
482–486.
Etter, Jonathan, John Berdahl, Bokkwan Jun, Matthew Caldwell, and Terry Kim. “Corneal Wound
Integrity and Architecture After Phacoemulsification: Comparative Analysis of Corneal Wounds Created
by Silicon and Steel Blades.” Journal of Cataract and Refractive Surgery 35, no. 7 (July 2009): 1313–1314.
Fine, I Howard, Richard S Hoffman, and Mark Packer. “Profile of Clear Corneal Cataract Incisions
Demonstrated by Ocular Coherence Tomography.” Journal of Cataract and Refractive Surgery 33, no. 1
(January 2007): 94–97.
Francis, Ian C, Athena Roufas, Edwin C Figueira, Vivek B Pandya, Gaurav Bhardwaj, and Jeanie Chui.
“Endophthalmitis Following Cataract Surgery: The Sucking Corneal Wound.” Journal of Cataract and
Refractive Surgery 35, no. 9 (September 2009): 1643–1645.
Fukuda, Shinichi, Keisuke Kawana, Yoshiaki Yasuno, and Tetsuro Oshika. “Wound Architecture of Clear
Corneal Incision with or Without Stromal Hydration Observed with 3-dimensional Optical Coherence
Tomography.” American Journal of Ophthalmology 151, no. 3 (March 2011): 413–419.e1.
Gajjar, Devarshi, Mamidipudi R Praveen, Abhay R Vasavada, Deepak Pandita, Vaishali A Vasavada, Dhara
B Patel, Kaid Johar, and Shetal Raj. “Ingress of Bacterial Inoculum into the Anterior Chamber After
Bimanual and Microcoaxial Phacoemulsification in Rabbits.” Journal of Cataract and Refractive Surgery
33, no. 12 (December 2007): 2129–2134.
Herretes, Samantha, Walter J Stark, Ashkan Pirouzmanesh, Johann M G Reyes, Peter J McDonnell, and
Ashley Behrens. “Inflow of Ocular Surface Fluid into the Anterior Chamber After Phacoemulsification
Through Sutureless Corneal Cataract Wounds.” American Journal of Ophthalmology 140, no. 4 (October
2005): 737–740.
Hovanesian, John A. “Cataract Wound Closure with a Polymerizing Liquid Hydrogel Ocular Bandage.”
Journal of Cataract and Refractive Surgery 35, no. 5 (May 2009): 912–916.
Hovanesian, John A, and Vicken H Karageozian. “Watertight Cataract Incision Closure Using Fibrin Tissue
Adhesive.” Journal of Cataract and Refractive Surgery 33, no. 8 (August 2007): 1461–1463.
Jacobi, F K, H B Dick, and R M Bohle. “Histological and Ultrastructural Study of Corneal Tunnel Incisions
Using Diamond and Steel Keratomes.” Journal of Cataract and Refractive Surgery 24, no. 4 (April 1998):
498–502.
Johnson, C Starck, Michel Wathier, Mark Grinstaff, and Terry Kim. “In Vitro Sealing of Clear Corneal
Cataract Incisions with a Novel Biodendrimer Adhesive.” Archives of Ophthalmology 127, no. 4 (April
2009): 430–434.
Kaja, Simon, Daryl L Goad, Fatima Ali, Ashley Abraham, R Luke Rebenitsch, Savak Teymoorian, Rohit
Krishna, and Peter Koulen. “Evaluation of Tensile Strength of Tissue Adhesives and Sutures for Clear
Corneal Incisions Using Porcine and Bovine Eyes, with a Novel Standardized Testing Platform.” Clinical
Ophthalmology (Auckland, N.Z.) 6 (2012): 305–309.
Kim, Terry, and Bhairavi V Kharod. “Tissue Adhesives in Corneal Cataract Incisions.” Current Opinion in
Ophthalmology 18, no. 1 (February 2007): 39–43.
Luo, Lixia, Haotian Lin, Mingguang He, Nathan Congdon, Ye Yang, and Yizhi Liu. “Clinical Evaluation of
Three Incision Size-dependent Phacoemulsification Systems.” American Journal of Ophthalmology 153,
no. 5 (May 2012): 831–839.e2.
Maddula, Surekha, Don K Davis, Peter J Ness, Michael K Burrow, and Randall J Olson. “Comparison of
Wound Strength with and Without a Hydrogel Liquid Ocular Bandage in Human Cadaver Eyes.” Journal
of Cataract and Refractive Surgery 36, no. 10 (October 2010): 1775–1778.
Marshall, J, S Trokel, S Rothery, and R R Krueger. “A Comparative Study of Corneal Incisions Induced by
Diamond and Steel Knives and Two Ultraviolet Radiations from an Excimer Laser.” The British Journal of
Ophthalmology 70, no. 7 (July 1986): 482–501.
Masket, Samuel, and Shaleen Belani. “Proper Wound Construction to Prevent Short-term Ocular
Hypotony After Clear Corneal Incision Cataract Surgery.” Journal of Cataract and Refractive Surgery 33,
no. 3 (March 2007): 383–386.
Masket, Samuel, Melvin Sarayba, Teresa Ignacio, and Nicole Fram. “Femtosecond Laser-assisted
Cataract Incisions: Architectural Stability and Reproducibility.” Journal of Cataract and Refractive Surgery
36, no. 6 (June 2010): 1048–1049.
May, William, Juan Castro-Combs, Walter Camacho, Priscila Wittmann, and Ashley Behrens. “Analysis of
Clear Corneal Incision Integrity in an Ex Vivo Model.” Journal of Cataract and Refractive Surgery 34, no. 6
(June 2008): 1013–1018.
May, William N, Juan Castro-Combs, Renata T Kashiwabuchi, Hans Hertzog, Woranart Tattiyakul, Yasin A
Kahn, Flavio Hirai, Emily W Gower, and Ashley Behrens. “Bacterial-sized Particle Inflow Through Sutured
Clear Corneal Incisions in a Laboratory Human Model.” Journal of Cataract and Refractive Surgery 37,
no. 6 (June 2011): 1140–1146.
May, William N, Juan Castro-Combs, Renata T Kashiwabuchi, Woranart Tattiyakul, Saima Qureshi-Said,
Flavio Hirai, and Ashley Behrens. “Sutured Clear Corneal Incision: Wound Apposition and Permeability to
Bacterial-Sized Particles.” Cornea (April 16, 2012).
May, William N, Juan Castro-Combs, Gilherme G Quinto, Renata Kashiwabuchi, Emily W Gower, and
Ashley Behrens. “Standardized Seidel Test to Evaluate Different Sutureless Cataract Incision
Configurations.” Journal of Cataract and Refractive Surgery 36, no. 6 (June 2010): 1011–1017.
McDonnell, Peter J, Mehran Taban, Melvin Sarayba, Bin Rao, Jun Zhang, Rhett Schiffman, and Zhongping
Chen. “Dynamic Morphology of Clear Corneal Cataract Incisions.” Ophthalmology 110, no. 12 (December
2003): 2342–2348.
Menabuoni, Luca, Roberto Pini, Francesca Rossi, Ivo Lenzetti, Sonia H Yoo, and Jean-Marie Parel. “Laserassisted Corneal Welding in Cataract Surgery: Retrospective Study.” Journal of Cataract and Refractive
Surgery 33, no. 9 (September 2007): 1608–1612.
Meskin, Seth W, David C Ritterband, Daniel E Shapiro, Jaroslaw Kusmierczyk, Susan S Schneider, John A
Seedor, and Richard S Koplin. “Liquid Bandage (2-octyl Cyanoacrylate) as a Temporary Wound Barrier in
Clear Corneal Cataract Surgery.” Ophthalmology 112, no. 11 (November 2005): 2015–2021.
Van Meter, W S, C Breen, D P Hainsworth, and R Geissler. “Scanning Electron Microscopy of Corneal
Incisions Using Steel, Diamond, and Sapphire Blades.” Ophthalmic Surgery 21, no. 7 (July 1990): 475–
480.
Mifflin, Mark D, Krista Kinard, and Marcus C Neuffer. “Comparison of Stromal Hydration Techniques for
Clear Corneal Cataract Incisions: Conventional Hydration Versus Anterior Stromal Pocket Hydration.”
Journal of Cataract and Refractive Surgery 38, no. 6 (June 2012): 933–937.
Ng, Jonathon Q, Nigel Morlet, Max K Bulsara, and James B Semmens. “Reducing the Risk for
Endophthalmitis After Cataract Surgery: Population-based Nested Case-control Study: Endophthalmitis
Population Study of Western Australia Sixth Report.” Journal of Cataract and Refractive Surgery 33, no. 2
(February 2007): 269–280.
Osher, Robert H. “Internal Flare: Modification of Wound Construction for Microincisional Cataract
Surgery.” Journal of Cataract and Refractive Surgery 38, no. 4 (April 2012): 721–722.
Packer, Mark, David F Chang, Steven H Dewey, Brian C Little, Nick Mamalis, Thomas A Oetting, Audrey
Talley-Rostov, and Sonia H Yoo. “Prevention, Diagnosis, and Management of Acute Postoperative
Bacterial Endophthalmitis.” Journal of Cataract and Refractive Surgery 37, no. 9 (September 2011):
1699–1714.
Praveen, Mamidipudi R, Abhay R Vasavada, Devarshi Gajjar, Deepak Pandita, Vaishali A Vasavada, Viraj A
Vasavada, and Shetal M Raj. “Comparative Quantification of Ingress of Trypan Blue into the Anterior
Chamber After Microcoaxial, Standard Coaxial, and Bimanual Phacoemulsification: Randomized Clinical
Trial.” Journal of Cataract and Refractive Surgery 34, no. 6 (June 2008): 1007–1012.
Radner, W, R Menapace, M Zehetmayer, C Mudrich, and R Mallinger. “Ultrastructure of Clear Corneal
Incisions. Part II: Corneal Trauma After Lens Implantation with the Microstaar Injector System.” Journal
of Cataract and Refractive Surgery 24, no. 4 (April 1998): 493–497.
Rosen, Emanuel S. “Incision Decisions.” Journal of Cataract and Refractive Surgery 34, no. 6 (June 2008):
877–878.
Sarayba, Melvin A, Mehran Taban, Teresa S Ignacio, Ashley Behrens, and Peter J McDonnell. “Inflow of
Ocular Surface Fluid Through Clear Corneal Cataract Incisions: a Laboratory Model.” American Journal of
Ophthalmology 138, no. 2 (August 2004): 206–210.
Schallhorn, Julie M, Maolong Tang, Yan Li, Jonathan C Song, and David Huang. “Optical Coherence
Tomography of Clear Corneal Incisions for Cataract Surgery.” Journal of Cataract and Refractive Surgery
34, no. 9 (September 2008): 1561–1565.
Shingleton, Bradford J, Rhonda B Rosenberg, Roberta Teixeira, and Mark W O’Donoghue. “Evaluation of
Intraocular Pressure in the Immediate Postoperative Period After Phacoemulsification.” Journal of
Cataract and Refractive Surgery 33, no. 11 (November 2007): 1953–1957.
Strehin, Iossif, Winnette McIntosh Ambrose, Oliver Schein, Afrah Salahuddin, and Jennifer Elisseeff.
“Synthesis and Characterization of a Chondroitin Sulfate-polyethylene Glycol Corneal Adhesive.” Journal
of Cataract and Refractive Surgery 35, no. 3 (March 2009): 567–576.
Taban, Mehran, Bin Rao, Jacob Reznik, Jun Zhang, Zhongping Chen, and Peter J McDonnell. “Dynamic
Morphology of Sutureless Cataract Wounds--effect of Incision Angle and Location.” Survey of
Ophthalmology 49 Suppl 2 (March 2004): S62–72.
Taban, Mehran, Melvin A Sarayba, Teresa S Ignacio, Ashley Behrens, and Peter J McDonnell. “Ingress of
India Ink into the Anterior Chamber Through Sutureless Clear Corneal Cataract Wounds.” Archives of
Ophthalmology 123, no. 5 (May 2005): 643–648.
Thoms, Susan S, David C Musch, and H Kaz Soong. “Postoperative Endophthalmitis Associated with
Sutured Versus Unsutured Clear Corneal Cataract Incisions.” The British Journal of Ophthalmology 91,
no. 6 (June 2007): 728–730.
Tsuneoka, H, and Y Takahashi. “Scleral Corneal 1-plane Incision Cataract Surgery.” Journal of Cataract
and Refractive Surgery 26, no. 1 (January 2000): 21–25.
Vasavada, Abhay R, Praveen R Mamidipudi, Devarshi Gajjar, Vaishali Vasavada, Viraj Vasavada, and
Shetal Raj. “Benefits of Stromal Hydration.” Journal of Cataract and Refractive Surgery 36, no. 3 (March
2010): 530.
Vasavada, Abhay R, Mamidipudi R Praveen, Deepak Pandita, Devarshi U Gajjar, Vaishali A Vasavada,
Viraj A Vasavada, Shetal M Raj, and Kaid Johar. “Effect of Stromal Hydration of Clear Corneal Incisions:
Quantifying Ingress of Trypan Blue into the Anterior Chamber After Phacoemulsification.” Journal of
Cataract and Refractive Surgery 33, no. 4 (April 2007): 623–627.
Walters, Thomas R. “The Effect of Stromal Hydration on Surgical Outcomes for Cataract Patients Who
Received a Hydrogel Ocular Bandage.” Clinical Ophthalmology (Auckland, N.Z.) 5 (2011): 385–391.
Wang, Li, Lena Dixit, Mitchell P Weikert, Richard B Jenkins, and Douglas D Koch. “Healing Changes in
Clear Corneal Cataract Incisions Evaluated Using Fourier-domain Optical Coherence Tomography.”
Journal of Cataract and Refractive Surgery 38, no. 4 (April 2012): 660–665.
Weikert, Mitchell P, Li Wang, James Barrish, Ramon Dimalanta, and Douglas D Koch. “Quantitative
Measurement of Wound Architecture in Microincision Cataract Surgery.” Journal of Cataract and
Refractive Surgery 38, no. 8 (August 2012): 1460–1466.