Laser refractive surgery station

A surgery station is provided for refractive eye surgery by laser photoablation, with the patient in a normal and comfortable upright seated position. The surgery station comprises a head support unit for retaining the head of the seated patient in a fixed position relative to an optical examination instrument such as an operating microscope, and further with respect to a laser beam for performing refractive surgery by corneal photoablation.

BACKGROUND OF THE INVENTION 
This invention relates generally to surgery apparatus and systems for 
performing laser refractive eye surgery. More specifically, this invention 
relates to an efficient and economical surgery station adapted for 
performing refractive surgery by corneal photoablation, with a 
physician-patient interface that is more convenient to the doctor and less 
threatening to the patient. 
Refractive eye surgery has undergone significant advances in recent years, 
with the result that refractive surgery has been successfully demonstrated 
and approved for correcting vision errors particularly such as myopia 
(near-sighted). Such refractive surgery has the capability to restore 
normal, substantially 20/20 uncorrected vision, so that a patient is no 
longer required to wear corrective eyeglasses or contact lenses. Surgical 
restoration of normal uncorrected sight has tremendous potential in terms 
of overall lifestyle, long range cost, and convenience to millions of 
patients suffering from near-sightedness and other vision defects 
including, but not limited to hyperopia (far-sighted), astigmatism, etc. 
Restoration of normal sight additionally opens numerous occupational 
opportunities, such as police and firefighting, to persons who would not 
otherwise meet vision criteria. 
Radial keratotomy (RK) is one refractive surgery technique which has been 
practiced in the United States for the past few decades. In radial 
keratotomy a series of precision radial incisions are formed in the 
peripheral cornea to selectively and controllably weaken the cornea such 
that the normal intraocular pressure causes the peripheral cornea to push 
outwardly. This results in a relative flattening of the central optical 
zone of the cornea. This technique has proven effective to correct mild 
myopia, with the degree of correction being a function of the incision 
number and depth. However, concern regarding the long term stability of 
the incised cornea, especially in response to an impact blow to the head, 
has been a deterrent to the use of radial keratotomy as a routine vision 
correction procedure. 
More recently, photorefractive keratectomy (PRK) has been developed and 
approved for use in the United States as a refractive surgery procedure. 
In photorefractive keratectomy, an excimer laser source is used to reshape 
the outer or anterior surface of the cornea by photoablation, 
substantially without significant weakening of the corneal structure. 
Photorefractive keratectomy can be used to correct a significant range of 
myopic conditions by flattening the central optical zone of the cornea, or 
to correct hyperopia by reshaping the perimeter region of the cornea 
relative to the central optical zone. This technique (PRK) is rapidly 
becoming the preferred method of performing refractive eye surgery, with 
one commercial excimer laser system being marketed under the name Star by 
VISX, Incorporated of Santa Clara, Calif. 
Photorefractive keratectomy (PRK) requires removal of the epithelium layer 
in the central optical zone to be reshaped by laser photoablation. Removal 
of the epithelium layer has been accomplished by scraping with a blunt 
edge spatula, although improved epithelium debridement brushes have 
recently become available and computer controlled laser techniques for 
epithelium removal are under development. Following epithelium removal to 
expose the cornea, the excimer laser is carefully aligned with the 
patient's eye and then operated in a precision and computer controlled 
manner to reshape the anterior surface of the cornea by photoablation, 
wherein corneal cells are removed to reshape the anterior surface in a 
custom manner to correct the refractive errors for the specific patient. 
Following the surgery, a bandage contact lens is normally placed on the 
eye for a few days during which the epithelium is allowed to heal. 
Current PRK surgical techniques and systems require the epithelium removal 
and the laser photoablation steps to be performed while the patient is 
laying down or reclined in a supine position. In this regard, current 
techniques and devices for epithelium removal have essentially restricted 
the procedure to a supine patient orientation in order to provide a 
conventional physician-patient surgical interface which is both familiar 
and comfortable to the doctor. 
Since it is extremely important to perform the laser photoablation step 
substantially immediately after epithelium removal, prior to any 
significant corneal drying, the laser surgery step has also been performed 
with the patient remaining in the supine position. Unfortunately, however, 
this doctor-patient interface with the patient in a supine position can be 
extremely threatening and intimidating to the patient. Moreover, this 
supine orientation requires the doctor to procure an appropriate operating 
table or special reclinable chair in order to perform laser refractive 
surgeries, thereby increasing the requisite equipment cost and resultant 
cost of the surgery to the patient. 
The present invention is directed to an improved surgery station for 
performing laser refractive eye surgery, wherein the patient is oriented 
in a comfortable and relatively nonthreatening upright seated position. 
SUMMARY OF THE INVENTION 
In accordance with the invention, an improved laser refractive surgery 
station is provided for performing photorefractive eye surgery by laser 
photoablation with the patient oriented in a normal and comfortable 
upright seated position. The surgery station comprises a head support unit 
for supporting and retaining the head of a seated patient in a fixed and 
predetermined position relative to an optical examination instrument such 
as an operating microscope. The optical examination instrument is in turn 
coupled with a laser unit including a laser light source and related 
control means for producing a precision controlled laser beam that is 
aligned via the optical examination instrument with the patient's eye to 
perform the photorefractive surgery. 
In one preferred form, the surgery station comprises a base frame such as a 
table having the head support unit mounted thereon, wherein the head 
support unit typically includes an adjustable chinrest and/or related 
forehead rest in a position to support and retain the head of a patient 
seated on a conventional chair. The head support unit orients the 
patient's head relative to the optical examination instrument to enable 
the physician to examine the left or right eye of the patient, preferably 
with the physician seated relative to the base frame in a position 
opposite to the patient. With this doctor-patient interface, surgical 
preparation can be performed quickly and easily, including anesthetizing 
the patient's eye and removing the epithelial layer from a central optical 
zone thereof by known epithelium removal techniques. 
The optical examination instrument is movably supported on the base frame 
to accommodate accurate alignment with the patient's eye. The examination 
instrument is optically coupled by an array of mirrors to the laser unit 
to deliver the controlled laser beam to the patient's eye to perform the 
corneal photoablative surgery. In this regard, the laser control means 
includes appropriate control elements mounted on the base frame in a 
position accessible to the physician to enable accurate and facilitated 
control over the surgical procedure. 
In one alternative form, the surgery station includes the head support unit 
and related optical examination instrument mounted on a base frame in the 
form of an upright support pole or the like, for swinging movement 
relative to a traditional opthamologic examination chair. In this 
embodiment, the laser unit and related control elements are situated on or 
adjacent to the base frame, with appropriate mirror means or the like for 
optically coupling the laser beam to the examination instrument. 
Other features and advantages of the present invention will become more 
apparent from the following detailed description, taken in conjunction 
with the accompanying drawings which illustrate, by way of example, the 
principles of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As shown in the exemplary drawings, a laser photorefractive surgery station 
referred to generally by the reference numeral 10 is provided for 
performing refractive eye surgery by corneal photoablation. The surgery 
station 10 is designed to orient the patient in an upright seated position 
which is more convenient to the doctor and less threatening to the 
patient. 
The photorefractive surgery station 10 of the present application is 
specifically designed to perform photorefractive keratectomy (PRK) by 
which an excimer laser of particular wavelength and power is used to 
reshape the anterior surface of the cornea to correct refractive vision 
errors. The excimer laser is applied to a central optical zone of the 
cornea and functions to remove corneal cells by photoablation, to restore 
substantially normal uncorrected vision to the patient. PRK has been used 
effectively to reshape the cornea by flattening the central optical zone 
to correct a myopic (near-sighted) condition, or to reshape a peripheral 
region of the optical zone to increase the corneal curvature to correct a 
hyperopic (far-sighted) condition. One commercial excimer laser system for 
performing PRK surgeries is available from VISX, Incorporated of Santa 
Clara, Calif. under the name Star. 
In general terms, the surgery station 10 of the present invention is 
designed to facilitate PRK surgeries in an economical yet precision 
controlled and safe manner, with the patient beneficially oriented in an 
upright seated position which is relatively nonthreatening. The surgery 
station 10 permits the entire refractive surgery procedure to be performed 
with both the patient and the physician disposed in a comfortable and 
substantially normal seated upright interface. The station 10 further 
accommodates use in combination with conventional and/or existing seating 
apparatus of the type commonly present in an opthamologist's office, 
thereby reducing or minimizing the need for special and costly equipment 
dedicated to refractive surgery use, and the need for dedicated floor 
space attributable to such equipment. As a result, the present invention 
effectively reduces the cost of PRK surgeries and thereby advantageously 
expands the availability of PRK surgery to a wider range of prospective 
patients. 
FIGS. 1 and 2 show the surgery station 10 in one preferred form to include 
a base frame 12 in the form of a simple table having a top 14 adapted for 
seated reception of a patient and a doctor on opposite sides thereof, 
wherein both individuals are seated on conventional chairs 16. An 
adjustable head support unit 18 is mounted on a patient side of the table 
12 and includes a forehead rest 20 in combination with a conventional 
chinrest 22 which is adjustable and preferably motorized for supporting 
and retaining the patient's head 24 (FIG. 3) in a fixed position relative 
to the table. An optical examination instrument 26 such as an operating 
microscope or slit lamp includes a viewer 28 mounted on the base frame 12 
at the doctor side of the table for use by the physician during 
preparation for and performance of the refractive surgery. A computer 
screen 30 and related keyboard control panel 32 are also provided on the 
base frame, in association with the examination instrument 26, for 
appropriate use by the physician. 
A laser unit 34 (FIG. 4) is mounted on the base frame 12 or in fixed 
relation thereto, such as by installing the laser unit 34 as part of a 
cabinet 36 forming a portion of the table. As shown, the laser unit 34 
comprises an excimer laser 40 with appropriate electronic modules 42 and 
gas supply canisters 44, for generating a laser beam used to perform the 
refractive surgery. A typical excimer laser for photoablation of the 
anterior surface of the cornea produces an ultraviolet beam having a wave 
length in the range of about 180-215 nanometers, and preferably about 200 
nanometers. An example of such excimer laser is an argon fluoride laser 
which produces a beam of light having a wave length of about 193 
nanometers. 
The laser light beam is reflected by an appropriately positioned array of 
mirrors 46 (FIG. 4) mounted on the base frame 12 to couple the laser beam 
to the optical examination instrument 26, which in turn controllably 
redirects the beam to the patient's eye to perform the photoablative 
surgery. Importantly, by use of the surgery station 10 of the present 
invention, the surgery can be performed quickly and easily, and without 
placing the patient in a threatening position or environment. 
More particularly, the surgery station is used as follows. The patient is 
positioned on the patient side of the table 12 in a normal upright seated 
position using a conventional chair 16 (FIG. 3). The patient's eye to be 
operated on is anesthetized by appropriate drops, and the patient's head 
24 is then positioned in a predetermined manner by means of the head 
support unit 18. The physician, also seated on a conventional chair 16, 
can then proceed to remove the epithelium in a central optical zone of the 
cornea in order to expose the underlying corneal tissue for laser 
photoablation. Removal of the epithelium is performed while the patient is 
seated, by use of a blunt edge spatula or an epithelial debridement brush. 
Alternately, the laser unit 34 can be aligned with the patient's eye to 
permit laser removal of the epithelium. 
In this regard, such alignment of the laser unit 34 with the patient's eye 
is accomplished by appropriate sliding or motor-driven adjustment of the 
viewer 28 of the optical examination instrument 26 preparatory to 
epithelium removal, so that the examination instrument 26 can be used by 
the physician during the epithelium removal step. When the epithelium 
removal is complete, the patient is already pre-positioned and pre-aligned 
with the laser unit 34 so that the photoablative surgery can proceed 
virtually immediately without needing to move the patient or otherwise to 
align laser devices with the patient's eye. Immediate performance of the 
laser surgery, as soon as possible following epithelium removal, enhances 
the accuracy of the photoablative process since there is no significant 
opportunity for the exposed corneal tissue to dry out before surgery. In 
addition, with the patient seated in the upright position, it is believed 
that photoablated material removal from the cornea will fall away from the 
patient's eye and not interfere with the surgical process, whereby 
improved vision correction results can be obtained. 
Following the surgery, the patient's eye is typically covered with a 
bandage contact lens for a few days during which the epithelium layer 
begins to reform and heal. 
FIG. 5 shows an alternative preferred form of the invention, wherein a 
modified patient chair 116 is provided in the form of a conventional 
patient examination chair of the type found in a typical opthamologist's 
office. A modified base frame 112 is mounted adjacent to the chair 116 and 
supports the head support unit 18 together with the optical examination 
instrument 26. FIG. 5 shows the base frame 112 in the form of a support 
pole with the head support unit 18 and the examination instrument 26 
mounted on a movable frame means such as a swingaway arm adapted for 
swinging movement between an operative position in front of the patient 
chair 116 and an out-of-the-way position displaced away from the patient 
chair. The examination instrument 26 is again optically coupled to the 
laser unit 34 which can be securely mounted as part of a common structure 
with the support pole, or otherwise securely mounted in a fixed or known 
position adjacent to the support pole. The surgery station shown in FIG. 5 
is used in the same manner as previously described with respect to the 
embodiment of FIGS. 1-4. 
For both versions of the invention as shown, the patient is seated in a 
comfortable and minimally intimidating position throughout the entire 
surgical procedure. As a result, the PRK surgery can be performed rapidly 
and efficiently, virtually in a walk-in, walk-out fashion, without 
necessitating the additional time and equipment for preparing, positioning 
and aligning the patient in a supine orientation. Moreover, the upright 
seated system of the invention is highly compatible with existing 
patient-seated opthamologic examination procedures and equipment, to 
minimize the space and equipment costs to provide for PRK surgery. 
A variety of further modifications and improvements to the invention will 
be apparent to those skilled in the art. Accordingly, no limitation on the 
invention is intended by way of the foregoing description and accompanying 
drawings, except as set forth in the appended claims.