Surgery – Instruments – Corneal cutter or guide for corneal cutter
Reexamination Certificate
1999-11-04
2003-08-26
Dawson, Glenn K. (Department: 3761)
Surgery
Instruments
Corneal cutter or guide for corneal cutter
C606S167000, C606S107000
Reexamination Certificate
active
06610075
ABSTRACT:
FIELD OF THE INVENTION
The invention herein relates to a keratome having a cutter head with a suspended stabilized reciprocating blade, an improved suction ring accepting an applanator and with entrance and cutting guideways for presenting and applying the cutter head and its suspended blade to the cornea, drive means for automated translation of the cutter head, and blade insertion cooperating with the cutter head.
BACKGROUND OF THE INVENTION
A keratome is an instrument used in ophthalmic surgery and, more particularly, in surgery to reshape the cornea for vision correction. A keratome incises a generally spherical segment of the cornea except for a connecting hinge. The cornea segment is lifted and held aside while the exposed truncated cornea surface is shaped for vision correction. Thereafter, the spherical cornea segment is repositioned to cover the shaped, truncated cornea surface. The cornea segment heals to the shaped surface, resulting in a reshaped cornea that acts as a corrective lens.
It will be appreciated that a keratome must achieve an accurately positioned, surgically precise cut with minimal tissue damage to enhance the healing process. Further, the cut must remain uncontaminated, also to aid the healing process and avoid irritation and infection.
In accurately positioning and performing a cornea cut, it is known to use a suction ring as an interface with the eye. Suction is used to temporarily secure the suction ring to the eye in a desired position. Typically, a suction ring is secured to the sclera, near the periphery of and surrounding the cornea.
It is also desirable to measure the cornea and coordinate the extent of the incision with the size of cornea in order to remove a properly sized cornea segment and to provide an appropriate hinge in conjunction with the excised cornea segment.
It is also known to apply a cutting instrument with the suction ring. Thus, the suction ring positions and presents the cutting instrument with respect to the cornea. Clearly, if any slippage or disengagement of the suction ring occurs, a correspondingly inaccurate cut may also occur. Present suction rings occasionally do experience slippage or disengagement, and it is believed this occurs because of a poor interface with the surface of the sclera resulting in loss of suction or uneven suction along various segments of the ring. Currently, engagement of a cutting instrument with a suction ring is often difficult to achieve, because the engagement must be precise, making the engagement difficult to initiate.
Precision of the cornea cut requires proper positioning of a cutting instrument with respect to the cornea, which is achieved by the location and secure attachment of the suction ring, and also requires a very smooth operating cutting blade. Cutting instruments often use a reciprocating cutting blade to achieve a smooth, precise incision. Any flutter in the operation of the reciprocating cutting blade can cause a somewhat ragged incision, with consequent difficulties in replacing the cornea segment and smooth healing thereof.
The cornea cut must also remain uncontaminated, because any foreign matter in the incision may become encapsulated and cause irritation and possible infection. Cutting instrument designs which support a cutting blade on a bearing surface adjacent the area of the incision increase the risk of contamination. Contact between the cutting blade and the bearing surface creates friction and wear. This not only heats the cutting blade, but also sloughs off microscopic metal wear particles. These may lodge in the cornea incision, with undesirable effect.
It is also desirable to translate the cutting instrument across the cornea in a smooth manner and to reliably stop the translation of the cutting instrument at the furthest extent of the cut. Non-damaging withdrawal of cutting instrument is also desirable.
There is also a need to quickly and easily load blades into the cutting instrument, and to remove blades after use.
Therefore, there is a need for a keratome including a suction ring that easily, accurately and securely positions a cutting instrument with respect to the cornea and that provides a surgically precise, uncontaminated incision of a cornea segment. There is an additional need for improved automation in making the incision.
SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the invention herein to provide a keratome for ophthalmic surgery.
It is an additional object of the invention herein to provide a keratome that achieves accurate and secure engagement with the eye.
It is another object of the invention to provide a keratome that facilitates accurate, pre-cut measurement of the cornea.
It is also an object of the invention to provide a keratome including a cutting instrument that is easily and accurately engageable with a suction ring secured to the eye.
It is an additional object of the invention to provide a keratome with automated translation of a cutting instrument across a suction ring.
It is a further object of the invention to provide a keratome that achieves an accurate and smooth cut.
It is another object of the invention to provide a keratome that avoids contamination of the incision made on the cornea.
It is also an object of the invention to provide a keratome with simple and efficient changing of the blade in a cutting instrument.
According to general aspects of the invention herein, a keratome generally comprises a suction ring and a cutting instrument having a cutter head guided into precision sliding engagement with the suction ring, the cutter head including a suspended, reciprocating blade. An applanator is receivable on the suction ring for measuring the segment of cornea to be cut, and the cutting instrument is adjustable or preset for length of cut.
Also according to aspects of the invention, a keratome generally comprises a cutting instrument having a cutter head including a reciprocating blade with a cutting edge extending below a sole surface, and a suction ring. The suction ring includes an eye ring adapted to be secured to an eye by suction and defines a cornea aperture presenting the cornea of the eye for cutting a cornea segment. The suction ring furthers includes a shoe from which the eye ring extends, the shoe defining a cutting guideway configured for receiving the cutter head in precision mating sliding engagement for passing the cutting edge of the cutter blade over the cornea aperture and thereby incising a cornea segment. The shoe further defines an entrance guideway extending from and generally aligned with the cutting guideway, the entrance guideway configured for receiving the cutter head in orienting sliding engagement positively positioning the cutter head into the aforesaid precision mating sliding engagement in the cutting guideway.
According to additional aspects, the cutter head defines two tongues extending downwardly at the edges of its sole surface, and the cutting guideway includes two guide grooves respectively receiving the tongues. The cutting guideway guide grooves are fully defined at the transition between the entrance guideway and the cutting guideway. According to further aspects, the entrance guideway is partially defined by a guide hoop of the shoe, and the cutter head is cooperatively shaped to enter the guide hoop and progressively orient the cutter head for entry to the cutting guideway. The guide hoop is preferably positioned substantially at the transition between the entry guideway and the cutting guideway. Also, according to further aspects, the entrance guideway includes curbs upstanding along the marginal edges of an entrance ramp portion of the shoe for generally aligning the cutter head with the guide hoop, the shoe defines side rails extending from the guide hoop, and the cutter head has side rail pockets slidingly receiving the side rails. Thus, there are multiple points of contact between the cutter head and the shoe defining the entrance guideway, serving to align the cutter head for sliding movement in the cutting guideway. The foregoing configurations o
Levesque Gaston J.
Sutton David F.
Becton Dickenson and Company
Dawson Glenn K.
Frederick James R.
Ware Fressola Van Der Sluys & Adolphson LLP
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