Download vision and sailing december 5, 1990

VISION AND SAILING
DECEMBER 5, 1990
Pam Pfister
5401 B Knoll Creek Drive
Hazelwood, MO 63042
731-0249
Cathy Phillips
Forest Hills Drive
Washington, MO 63090
225-7809
Modified by C. Hillier
SAILING
SAILING OVERVIEW
History: Although records of the most ancient sailing vessels have perished, it is known that the
Dutch were building and using yachts in the early 1600s, both for pleasure and trade. The
world's first yacht club was formed in 1720 in Ireland, and it was through this organization that
racing became a feature of yachting.
Sailing in America became popular as a means of easy transportation in a country without roads.
Racing was not initiated in the states until the mid-1800s. The first race for the America's Cup
took place in 1851, and since then, there have been more than twenty challenges for the cup.
The time period immediately following the Civil War is known as the "Big Schooner Era", and it
was not until the turn of the century that small-boat sailing found popularity. Today, the modern
classifications of sailing yachts consist of different racing classes: cruising yachts for cruising,
racing, or both; day sailors with neither competitive intentions nor overnight cruising abilities;
and catamarans. Within these broad classifications, there is great variety.
Synopsis: Today there are two general types of sailing craft: single-masted and double-masted,
and two sail plans: jib-headed (triangular-shaped sail) and gaff-headed (rectangular-shaped sail).
Sailboat hulls are divided into two definite types - centerboard and keel (see Sailing Terms
section). The main function of both devices is to furnish lateral resistance to keep the boat from
sliding sideways through the water. To carry the sail, masts are fitted into the hull. In addition,
rigging is used to help support and distribute the stresses to the hull proper.
Since the wind is the "power", a sailor must learn how to make the best use of it. When wind
fills a sail, it not only pushes the boat, but reduces the pressure on the sail's other side, which
pulls the hull along. The direction of the wind is up to nature, so the sailor must be able to reach
his or her destination regardless of which way it is blowing. The sources listed below are
excellent references from which the sailor can learn the art of sailing.
General Sailing Sources:
1.
See Encyclopedia of Sailing by the editors of One-Design & Offshore Yachtsman, with
Robert Scharff and Richard Henderson, an excellent illustrated book about sailing
including its history, equipment, catalog of boats, sailing rules and technique,
competition results, racing tactics, meaning of terms, and how to get the greatest
enjoyment from sailing.
2.
See This Is Sailing, A Complete Course by Richard Creagh-Osborne, a highly illustrated
book of sailing instruction.
3.
See Practical Sailing by Tony Gibbs, a guide to handling today's sailboats in fair or foul
weather.
SAILING TERMS
A very thorough glossary of sailing terms can be found in the Encyclopedia of Sailing listed
earlier. Some of the more common terms are defined as follows:
Aground: When the hull or keel of a boat touches the bottom.
Angle of Heel: Of a sailboat, its angle from the vertical at a given moment, depending on the
strength of wind, point of sailing, and stability of the hull.
Apparent Wind: The direction from which the wind appears to blow when aboard a boat in
motion.
Backstays: Rigging wires that lead from mast top aft to the ship's sides.
Batten: A thin wooden, metal, or plastic strip placed in a pocket in the leech of a sail to help
hold its form.
Beam: The maximum width measurement of a vessel. Also, in radio, a signal transmitted along
a narrow course for use in direction finding.
Bow: The forward end of a boat.
Capsize: Upset; turn over.
Centerboard: A keel-like device that can be hoisted or lowered in a well, or in a trunk, to act as
a keel in shoal-draft boats.
Come About: To bring the boat from one tack to the other when sailing into the wind.
Come Up Into the Wind: Steer toward the direction from which the wind is coming.
Daggerboard: A type of centerboard which does not pivot on a hinge, but is raised and lowered
vertically in the trunk.
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Fore-and-Aft: In the direction of the keel, from front to back.
Genoa: A large, overlapping jib or headsail which reaches the top of the forestay and whose
clew overlaps the mainsail. It is the principal power source on a modern racing sloop when
beating. Also called jenny.
Halyard: A line used to hoist sails.
Headsails: All sails forward of the mast.
Heel: The tilt, tip, listing, or laying over of a boat, usually due to the wind.
Helm: The tiller or wheel by which the rudder is controlled.
Jib: A triangular sail set forward of the mast.
Keel: The backbone of a boat running fore-and-aft.
Mainsail: The largest regular sail on a modern sailboat.
Mast: The vertical spar supporting the booms, sails, etc.
Port: The left side of a boat, looking toward the bow. Also, a harbor or place where vessels
enter and leave, as for commerce.
Rigging: A general term applying to all lines, shrouds, and stays necessary to spars and sails.
Sheet: A line used to trim a sail.
Spar: Mast, boom, spinnaker pole, etc.
Spinnaker: A large, light headsail used when a boat is sailing before the wind, or on a reach.
Starboard: The right side of a boat, looking toward the bow.
Stern: The back end of a boat.
Tack: To proceed to windward by sailing on alternate courses so that the wind is first on one
side of the boat and then on the other.
Telltale: Any pennant, feather, or piece of wool at the masthead or on the shrouds which
indicate wind direction. Same as masthead pennants.
Tiller: A bar connected with the rudder head. By this bar, the rudder is moved as desired.
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VISUAL DEMANDS OF SAILING
1.
Visual Acuity: Both static and dynamic visual acuity are important in sailing, due to the
need to discriminate fine detail when looking for buoys, markers, wind on the surface of
the water, other boats in the distance, etc. Although sailing is generally not a very fastmoving sport, dynamic visual acuity may become important in foul weather and other
extreme conditions.
2.
Peripheral Vision: Because sailboats tend to be very quiet, peripheral vision is
important in the detection of other boats or objects on either side of his or her sailboat.
3.
Depth Perception: Similar to driving a car, poor depth perception contributes to
decreased performance.
4.
Color Perception: A decrease in the ability to carefully discriminate colors would
become a factor in racing, where colored flags are used to mark the start and finish lines.
This would also impair the sailor's ability to distinguish the different colored marker
lights on buoys, especially at night.
5.
Eye Dominance: Not a particularly important factor in sailing, due to the nature of the
sport.
6.
Fixation Ability: Maintenance of fixation on a navigational or coastal target may be
crucial when navigating.
7.
Visual Memory: This would be important when racing around courses and in some
aspects of navigation such as tacking, recalling previous courses, shoals, conditions, etc.
8.
Central/Peripheral Awareness: This becomes important in racing conditions where the
sailor must maintain awareness of the whereabouts of other boats and navigational
markers.
9.
Spatial Localization: The sailor must maintain awareness of the location of other boats
with respect to his or her craft.
10.
Glare Sensitivity: Because it is a water sport, sailing exposes its participants to a large
amount of glare; this can be a hindrance to the glare-sensitive sailor.
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VISUAL SCREENING/TESTING PROCEDURES FOR SAILING
1.
Static Visual Acuity
a.
b.
2.
Dynamic Visual Acuity
a.
b.
c.
3.
AO Vectographic Slide
Randot
Stereo Fly
Vectograms (distance and near)
Keystone Visual Skills
Ocular Motility
a.
b.
c.
d.
7.
Automated perimeter
Wayne P.A.T. (Peripheral Awareness Tester)
B & L Vision Tester with Attachment
Depth Perception
a.
b.
c.
d.
e.
6.
Vistech Tester
Stereo Optical Contrast Sensitivity Targets
Peripheral Vision
a.
b.
c.
5.
Kirschner Rotator
Keystone or Bernell Rotator with Sherman Chart
Motorized J.W. Engineering Rotator
Contrast Sensitivity
a.
b.
4.
Normal Snellen Acuity Chart
Vectographic Chart
AcuVision 1000
Wayne Saccadic Fixator
Entrance Eye Movements
Projected King-Devick
Refractive Condition
a.
b.
c.
Autorefractor
Retinoscope
Subjective Testing
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8.
Eye/Hand/Body/Foot Coordinator
a.
b.
c.
d.
9.
Binocular Posture
a.
b.
10.
Night Sight Meter
Visual Localization
a.
b.
c.
16.
Bassin Anticipation Timer
Wayne Speed Trac
Glare Recovery/Night Vision
a.
15.
Tachistoscope
AccuVision 1000
Timing/Anticipation Skills
a.
b.
14.
+2.00/-2.00 Flipper
8 BI/8 BO Flipper
Speed/Span of Recognition
a.
b.
13.
Ishihara Plates
B & L Vision Tester
Accommodative Flexibility
a.
b.
12.
Cover Test
Von-Graefe (lateral and vertical)
Color Vision
a.
b.
11.
Wayne Saccadic Fixator with Footboard
AcuVision 2000
Reaction Plus
Reaction Coach
Brock String
Projected Stereoscopic Slides
Vectograms
Ocular Health
a.
b.
Ophthalmoscope
Binocular Indirect Ophthalmoscope
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c.
d.
Tonometer
Visual Fields Tester
VISION TRAINING TECHNIQUES WHICH MIGHT ENHANCE PERFORMANCE OF
THE VISUAL SKILLS IMPORTANT FOR SAILING
1.
Visual Acuity: Best-correctable visual acuity, via a correct spectacle prescription, will
optimize performance. Water spraying on spectacles is detrimental to acuity, and glare
and bright sunlight may also effect performance, so the sailor may have to choose which
is most important to him or her - soft contact lenses for unencumbered vision, or polaroid
goggles for protection from glare, ultraviolet radiation, and water.
2.
Peripheral Vision
a.
b.
c.
3.
Depth Perception
a.
b.
4.
Excellent stereopsis is the goal. Training binocularity with BI and BO prism, with
vectograms and anaglyphs, and other stereo targets should enhance visual function
and result in enhanced stereopsis.
Red/green sports tranaglyphs from Bernall can help build ranges.
Ocular Motility
a.
b.
c.
d.
5.
Awareness of peripheral vision can be enhanced (see Central/Peripheral Awareness
section, no. 14).
If a visual field defect is present, the sailor can be counseled on how to compensate
for the difficulty.
Field expansion devices can be prescribed.
Pegboard Rotators
AcuVision 2000
Computerized Anaglyphic Trainer
Wayne Saccadic Fixator
Eye/Hand/Body/Foot Coordination
a.
b.
c.
d.
Wayne Saccadic Fixator:
1) Normal use with the hands
2) Balance Board helps train the sailor's balance system in response to visual
signals.
Balance Board
Fitter
Billy Board
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6.
Visualization: Visualization is very important when remembering what was seen on a
chart previously. Below is an example of how to use the principles of visualization.
a.
b.
7.
Speed of Recognition
a.
b.
8.
Analyze: Before sailing, the sailor must incorporate as much visual detail about the
plan of action into his or her visual memory. Orientation of where equipment and
ropes are will improve performance. Try to keep a visual videotape of the details
for your mind to replay later while sailing.
Visualize: Use the time before sailing to replay the mental videotape to yourself,
seeing specific details about your plan. Break down specific parts of your plan into
detail. The more sensory modalities you incorporate into your visualization
process, the more it will support you later. Precede your performance with a visual
picture of you performing the desired action (e.g., the perfect turn).
Train this visual skill with the same instruments used to measure or test this skill.
Make progressions from easy toward most difficult.
Speed of Focusing
Train with Red/Green Anaglyphic accommodative rock or flippers.
9.
Glare Recovery Speed
a.
b.
c.
10.
No specific training.
Antireflective coatings and polaroid lenses may be used if eyewear is worn.
Perhaps Vitamin A and B2 therapy.
1) Vitamin A therapy = 10,000 units/day
2) Vitamin B2 (Riboflavin) therapy = 2.5 milligrams/day
Ability to See in Dim Illumination
a.
b.
c.
Antireflective coatings.
High transmission lenses if the athlete uses glasses.
Vitamin therapy as above.
11.
Ability to Withstand Eye Fatigue Without Decreased Performance: Use
visualization as much as possible while competing to enhance concentration and give the
sailor a definite plan of attack. This is very helpful in pulling him or her through the
competition, even when the athlete becomes fatigued. Visualization should help provide
a consistency so performances will not be erratic.
12.
Color Perception: Consultation so the sailor can work around his or her problem and
negate its effect.
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13.
Visual Memory
a.
b.
c.
14.
Central/Peripheral Awareness
a.
b.
c.
d.
15.
Tachistoscope.
Barrier Techniques.
The Memory Book by Jerry Lucas is a good reference for understanding and
applying principles of visual memory more fully.
Wayne "stick-ups" are good for training.
AcuVision 2000.
As you go about your day, just concentrating on how much detail you can gather
from your periphery without actually looking directly at the details (with central
fixation) is great training for this visual skill.
This skill is not something that is developed overnight. You have to work at it
daily until you are good at it. This skill should transfer well to sailing.
Spatial Localization
a.
b.
Train with the same instruments and equipment you use to measure and test this
skill.
Instruments:
Brock String (in all 9 positions of gaze).
SAILING-RELATED SPORTS VISION PROBLEMS
PROBLEM
POSSIBLE SOLUTION
1. Wind: Contact lenses tend to dry out and
be uncomfortable.
Good lubrication solutions for both hard and
soft lenses can help. Instill a few drops per eye
before race and as needed. Sunglasses.
2. Vision correction needed: Wind and
water splashing into eyes can hinder
optimal correction.
Soft contact lenses provide unencumbered
vision. The athlete should be educated on how
to prevent washout. Protective eyewear
provides the advantage of tint and protection
from injury, but spray or loss of eyewear make
this less than optimal.
3. Glare and sunlight: During daylight
hours, both can be a problem, especially
glare in contact lens wearers.
Dark-tinted or polaroid lenses with a glare coat
are optimal for water glare.
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4. Loss of spectacles from water splash.
Floatation device or sports strap should be
implemented. Sports goggles should also have
holes in the sides to prevent fogging. Contact
lenses are optimal. To further avoid their loss,
advise the sailor to hold his or her lids tightly
closed when chances of washout are greatest.
MOST COMMON OCULAR INJURIES SUSTAINED DURING SAILING
Studies have shown that significant injuries may be more of a problem for competitive, elite
sailors who sail in high wind and use faster equipment. Inexperienced sailors are also at risk for
injury.
1.
Environmental consequences:
a.
b.
c.
d.
e.
f.
cataracts
pterygium
dry eye
ultraviolet retinitis
splash keratosis
skin cancer
2.
Corneal abrasion
3.
Bacterial conjunctivitis
4.
Trauma to the globe may result in:
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
periorbital contusions, edema or fracture
blow-out orbital fracture
entrapped extraocular muscles
subconjunctival hemorrhage
miotic, mydriatic, or fixed pupils
iris defects
hyphema
angle recession
traumatic cataract
vitreous hemorrhage
retinal hemorrhage, tears, or detachment
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PROTECTIVE/CORRECTIVE EYEWEAR FOR SAILING
Eyewear for sailors should fulfill several requirements, including best-visual acuity, stable
vision, and protection. Soft contact lenses are rapidly replacing other forms of correction in
most sports, because they provide a natural vision condition. The capillary attraction provides
greater stability/centration of a soft contact lens than rigid. Peripheral vision is not hindered,
because the lens moves with the eye. Also, soft contact lenses do not fog up or get dirty like
spectacles do. To further improve the patient's success with soft contact lenses and sailing,
several guidelines should be followed:
1.
Fit the flattest keratometry reading that will remain stable. Use a soft contact lens with a
large diameter (2.0-2.5 mm beyond the limbus) to increase centration and stability. A
lens such as the Sport Mate is ideal; it is a large-diameter lens, with a mid-water content.
Its large OZD decreases flare, glare, and distortions. Sailing accentuates the risk of
losing soft contact lenses because of the intensity of impact when the sailor is splashed
with water. To further avoid this, advise the patient to hold his or her lids tightly closed
when chances of washout are greatest.
2.
Disinfect soft contact lenses immediately after water activity to decrease the chance of an
organism causing an infection.
3.
Put lenses in a half hour before water activity to fully adapt to lenses.
Other alternatives for those who are not candidates for soft contact lenses are prescription
protective goggles. The optimal goggle has holes in the side to prevent fogging, ultraviolet
protection, a glare coat, a floatation device, and a polaroid or tinted lens.
OCULAR SUPPLIES NEEDED IN A SAILOR'S FIRST AID KIT
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Sterile eyewash
Q-tips
Penlight
Oval eye pads
Gauze pads
Dermacel tape
Ice pack
Butterfly bandages
Artificial Tears
DMV
Saline
Spare, labeled contact lenses
Phone numbers of eye care professionals
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APPROPRIATE EMERGENCY FIRST AID FOR SAILING INJURIES
The skipper or additional crew should know how to:
1.
2.
3.
4.
5.
Instill ophthalmic drops
Lavage an eye with a foreign body
Handle contact lenses (hard and soft) and remove them from the eye.
Lacerations should be closed with a butterfly bandage and evaluated for stitches.
With any blunt trauma, an ice pack should be applied immediately and the individual
taken to an optometrist or ophthalmologist for examination.
BIBLIOGRAPHY
Contact Lenses for Dynamic Sports. International Academy of Sports Vision, vol. 6, F2,
Summer 1990.
Creagh-Osborne, Richard. This Is Sailing, A Complete Course. United Nautical Publishers,
1972.
Encyclopedia of Sailing. Harper & Row Publishers, 1971.
Gibbs, Tony. Practical Sailing. The Haddon Craftsmen, Inc., 1971.
Gregg, James R. Vision and Sports. Butterworths, 1987.
Injuries in Sailboard Enthusiasts. British Journal of Sports Medicine, vol. 22, F3, Sept. 1988, pp.
95-97.
Sports and Vision News Backgrounder. American Optometric Association, May 1982.
©1998 American Optometric Association
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