Dynamics of big bubble formation in deep anterior lamellar keratoplasty by the big bubble technique: <i>in vitro</i> studies

Dua, Harminder S; Faraj, Lana A; Kenawy, Mohamed B.; Al-Taan, Saief Laith Muhamed; El‐Alfy, Mohamed; Katamish, Tarek A; Said, Dalia G.

doi:10.1111/aos.13460

Cited by 47 publications

(32 citation statements)

References 25 publications

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“…In the BB procedure, air is injected into the recipient stroma through a trephine cut of desired diameter (usually 7.5–8 mm). Injected air follows a defined and reproducible path[ 49 ] to reach the PDL plane, to produce a Type-1 BB. This is the most common type, occurring in approximately 80% of patients.…”

Section: Deep Anterior Lamellar Keratoplastymentioning

confidence: 99%

Lamellar keratoplasty techniques

Singh

Said

Dua

2018

Indian J Ophthalmol

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Lamellar keratoplasty (LK) has revolutionized corneal graft surgery in several ways. Deep anterior LK (DALK) has eliminated risk of failure due to endothelial rejection. Endothelial keratoplasty (EK) has almost eliminated induced astigmatism and the “weak” graft–host junction as seen with penetrating keratoplasty (PK) and also reduced the risk of endothelial rejection. LK provided new insights into posterior corneal anatomy that led to better understanding and performance of DALK and to the development of another EK procedure, namely pre-Descemet's EK (PDEK). Surgical procedures for LK were further refined based on the improved understanding and are able to deliver better surgical outcomes in terms of structural integrity and long-term patient satisfaction, reducing the need of further surgeries and minimizing patient discomfort. In most specialist centers, anterior lamellar techniques like DALK and EK techniques like Descemet's stripping EK (DSEK) and Descemet's membrane EK (DMEK) have replaced the full-thickness PK where possible. The introduction of microkeratome, femtosecond laser, and PDEK clamp have made LK techniques easier and more predictable and have led to the innovation of another LK procedure, namely Bowman membrane transplant (BMT). In this article, we discuss the evolution of different surgical techniques, their principles, main outcomes, and limitations. To date, experience with BMT is limited, but DALK has become the gold standard for anterior LK. The EK procedures too have undergone a rapid transition from DSEK to DMEK and PDEK emerging as a viable option. Ultrathin-DSEK may still have a role in modern EK.

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Section: Deep Anterior Lamellar Keratoplastymentioning

confidence: 99%

Lamellar keratoplasty techniques

Singh

Said

Dua

2018

Indian J Ophthalmol

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“…The response is different between injection of air and injection of viscoelastic. Injected air follows a consistent path through spaces between lamellae (presumably around keratocytes) to reach the plane between the PDL (impervious to air) and deep stroma, separating the two in a type 1 BB, or through peripheral fenestrations in PDL to access the plane between PDL and DM to form a type 2 BB 11. No IBB occurred with air injection.…”

Section: Discussionmentioning

confidence: 95%

“…No IBB occurred with air injection. Though air takes a consistent path intrastromally11 a BB does not always result in vivo possibly due to the altered collagen content of scarred or keratoconus corneas. The path traversed by air appears to be too narrow for the viscoelastic used.…”

Section: Discussionmentioning

confidence: 99%

Deep anterior lamellar keratoplasty: dissection plane with viscoelastic and air can be different

et al. 2018

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BB obtained by injection of viscoelastic and air can be different. The former tends to occur at the site of injection, especially with midstromal injections, takes the form of tissue separation by stretch and tearing and does not cleave in a consistent plane like air. Surgeons should be aware of IBB created by viscodissection and not confuse it for a type1 BB. Intraoperative OCT should help identify IBB.

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“…The volume of air required to achieve the critical tissue pressure depends on the escape of air through the trabecular meshwork or through distinct peripheral holes in the stroma, during injection. [7][8][9] This confounder was eliminated by the use of the clamp, which prevented any escape of air, thus giving us an accurate measure of the mean tissue pressure required to create a BB overcoming tissue resistance, which was 96.25 +/ − 21.61 kpa. It has been recently demonstrated that air injected in the corneal stroma follows a consistent path regardless of the location, direction of bevel, and depth of the needle tip in the stroma.…”

Section: Discussionmentioning

confidence: 99%

“…It has been recently demonstrated that air injected in the corneal stroma follows a consistent path regardless of the location, direction of bevel, and depth of the needle tip in the stroma. 9 Once a type-1 BB was created, the intrabubble pressure was ascertained by advancing the needle into the cavity of the BB. This measured 10.16 +/ − 3.65 kpa.…”

Section: Discussionmentioning

confidence: 99%

Air pressure changes in the creation and bursting of the type-1 big bubble in deep anterior lamellar keratoplasty: an ex vivo study

AlTaan

Mohammed

Said

et al. 2017

Eye

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PurposeTo measure the pressure and volume of air required to create a big bubble (BB) in simulated deep anterior lamellar keratoplasty (DALK) in donor eyes and ascertain the bursting pressure of the BB.Patients and methodsTwenty-two human sclera-corneal discs were used. Air was injected into the corneal stroma to create a BB and the pressure measured by means of a pressure converter attached to the system via a side port. A special clamp was designed to prevent air leak from the periphery of the discs. The pressure at which air emerged in the corneal tissue; the bursting pressure measured after advancing the needle into the bubble cavity and injecting more air; the volume of air required to create a BB and the volume of the BB were ascertained.ResultsType-1 BB were achieved in 19 and type-2 BB in 3 eyes. The maximum pressure reached to create a BB was 96.25+/- 21.61 kpa; the mean type-1 intrabubble pressure was 10.16 +/- 3.65 kpa. The mean bursting pressure of a type-1 BB was 66.65 +/- 18.65 kpa, while that of a type-2 BB was 14.77 +/- 2.44 kpa. The volume of air required to create a type-1 BB was 0.54 ml and the volume of a type-1 BB was consistently 0.1 ml.ConclusionsDua's layer baring DALK can withstand high intraoperative pressures compared to Descemet's membrane baring DALK. The study suggests that it could be safe to undertake procedures such as DALK-triple with a type-1 BB but not with a type-2 BB.

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Dynamics of big bubble formation in deep anterior lamellar keratoplasty by the big bubble technique: in vitro studies

Cited by 47 publications

References 25 publications

Lamellar keratoplasty techniques

Lamellar keratoplasty techniques

Deep anterior lamellar keratoplasty: dissection plane with viscoelastic and air can be different

Air pressure changes in the creation and bursting of the type-1 big bubble in deep anterior lamellar keratoplasty: an ex vivo study

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