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Running and the eye.

Edsel Ing, MD, FRCSC, Associate Professor, University of Toronto, Ophthalmology

Address for correspondence: Edsel Ing, MD; Toronto Eyelid Strabismus & Orbit Surgery Clinic; Toronto East General Hospital; 650 Sammon Avenue, K306; Toronto, Ontario M4C 5M5; E-mail: eingLidStrab@aol.com; Fax: 416-385-3880.

Dr. Ing has no financial interests in any of the products or technologies discussed in this article.

Introduction

This article reviews some of the vision problems that may affect runners starting with the front of the eye, and proceeding posteriorly. The topics discussed include refractive errors, unstable tear film, eyelid problems, glaucoma, cataract, and retinal problems. Pupil abnormalities, diplopia, and transient visual loss have been grouped under neuro-ophthalmic entities. The conclusion of the article discusses guidelines for return to running after eye surgery, eye injuries in runners and their possible prevention, and runners with visual handicaps.

Dry Eyes

One of the most common reasons for ophthalmic consultation is ocular irritation from ''dry eyes" or more appropriately tear film instability. The tear film protects and comforts the eyes, and the high index of refraction between air and tears makes for an important refractive surface that facilitates clear vision.

Patients with tear film instability frequently complain of sandy, burning eyes, worse at the end of the day, or after prolonged reading or driving. The gritty, burning sensation from an unstable tear film is often exacerbated by the air currents and increased evaporation during endurance running, especially with cold weather events and arid environments.

Paradoxically patients with unstable tear film may have watery eyes, from reflex tearing when the eye is trying to protect itself from corneal exposure.

There are many potential treatments for dry eyes, the most common being artificial tears and ointments. Tear drops are easier to use during a race than ointment. Artificial tears can be in bottles which contain preservatives, or in single use packets which are preservative free, and less irritating to the eye. Ointments last longer than tear drops, but can cause transient blurry vision.

Some runners with dry eyes may like the slow release hydroxypropyl cellulose pellets, called Lacriserts, which are instilled in the lower fornix of the eye and dissolve over several hours. Liposomal sprays to the closed eyelids can also help patients with dry eyes.

Glasses are a simple method to decrease tear evaporation. Another method of preserving tears are punctal plugs which can be permanent or temporary.

The quality of the tear film may be improved by nutritional supplementation, with dietary omega-3 supplementation.

Refractive Error

Many runners with refractive error prefer contact lenses to glasses when running. Runners with refractive error may complain that spectacles move with each stride. Contact lens proponents indicate there is less fogging and splattering with contacts, especially during inclement weather. In extreme cold, though, contact lenses can freeze on the eye.

The most commonly available contacts are the larger diameter, flexible soft contact lenses. Soft contacts are more comfortable and due to their increased surface area, are less prone to dislodge. Rigid gas permeable lenses require daily wear for comfortable adaptation. The rigid contact corrects astigmatism better, and the hard surface is more impermeable making the lenses easier to clean. Most rigid gas permeable lenses have higher oxygen permeability than soft contacts, which is better for the avascular cornea. Hybrid contact lenses with a rigid center but soft peripheral carrier are available for patients with high astigmatism who cannot wear toric soft lenses, but want more comfort than a typical rigid lens.

The contact lens wearer with dry eyes can consider the following during endurance running or training. New lenses tend to be more comfortable. Meticulously cleaned lenses are better tolerated. Increasing the blink rate is a simple way to increase corneal wetting, and rewetting drops can be used. Soft contacts designed for dry eyes include Acuvue Oasys and Proclear Compatibles.

Many runners with refractive error have chosen or are contemplating laser-assisted in situ keratomileusis (LASIK). LASIK is a corneal refractive procedure where a hinge flap of the cornea is made and the underlying corneal stroma is excimer lasered, altering the refractive power. LASIK is potentially cheaper than long-term use of contacts and will not dislodge like contacts, although there is a chronic risk of flap dehiscence with trauma. Dry eyes may become markedly worse after LASIK and, of course, some runners may find this uncomfortable. Glare and halos sometimes occur post-LASIK which can be more problematic at night when the pupils dilate. Myopic athletes who get LASIK in their late 30s or early 40s may have more difficulty viewing their running watch or bicycle computers due to presbyopia.

Ultraviolet Radiation & the Eye

Ultraviolet radiation can cause many ocular problems including skin cancer, pterygia and pingeculae (solar elastoses), corneal keratopathy, cataracts (lens opacity), and possibly macular degeneration.

UVB ultraviolet radiation, in particular, causes sunburn which predisoposes to skin cancer. UVA, however, is also potentially carcinogenic, and is thought to cause wrinkles and sun damaged skin.

The incidence of skin cancers such as basal cell carcinoma, squamous cell carcinoma, and melanoma has increased dramatically over the last few decades. It is not uncommon for clinicians to see skin cancer patients in their fourth or fifth decade, even in temperate climates. Sunscreen cannot be applied close to the eye, so structures such as the eyelid margin are particularly at risk.

The prevention of skin cancer must begin in childhood (1) as most of the lifetime sun damage to the skin occurs during the pediatric years. It is unfortunate that many children are not using a hat, sunglasses or sunscreen during recess, outdoor gym class or after school, which often coincide with peak periods of sun exposure.

Sunglasses with 100% UV absorption should state on their label UV absorption up to 400 nm. Broad brimmed hats offer better sun protection than caps.

Glaucoma

Glaucoma is an optic neuropathy from accelerated attrition of the ganglion cells, in part due to higher intraocular pressure than the individual eye can withstand. Patients with primary open angle glaucoma or simple glaucoma can continue to run, knowing that jogging decreases intraocular pressure, even in patients who are already using glaucoma drops (2). However, pigment dispersion, a form of secondary open angle glaucoma, might be made worse with exercise. With pigment dispersion glaucoma, the lens zonules rub against the posterior surface of the iris and release pigment that may clog the trabecular meshwork and increase intraocular pressure.

Subluxated Lens & Cataracts

Trauma, collagen abnormalities, and homocystimiria may predispose to the uncommon finding of lens subluxation or dislocation. Because a subluxated lens may still have some useful refractive power and since lens removal is not always complication-free, some patients co-exist with their lens problem. However, patients with ectopia lentis, who participate in endurance running, are at chronic risk of exacerbating their lens malposition. This may lead to corneal compromise or glaucoma

The National Runners Health Study, a prospective epidemiologic cohort study found that men who Tan 64 km (approx. 40 miles) per week had a 35% lower risk of cataract than those who ran less than 16 km (approx. 10 miles) per week (3). Furthermore, men who had the fastest 10K finish times had half the risk of developing cataracts compared to the least fit men. One of the proposed mechanisms for this finding is that running decreases C reactive protein, and C reactive protein may be a mediator for cataract development.

Retinal Problems

Age-related macular degeneration is the leading cause of central visual loss in people over age 50 and affects 15 million North Americans. A healthy retina is comparable to a healthy lawn of green grass. In dry macular degeneration, the diseased retinal pigment epithelium and drusen cause bald spots in the "lawn." In wet macular degeneration, there is choroidal neovascularisation, akin to weeds growing in the bald spots of the lawn. The National Runners Health study also found that runners with higher mileage had decreased risk of age-related macular degeneration. HDL cholesterol is increased with exercise (4) and elevated HDL cholesterol correlates with a lower risk of macular degeneration.

For the great majority of the population, exercise reduces the risk of diabetes, hypertension, and central retinal vein occlusion (5). This is notwithstanding the several case reports of central retinal vein occlusion and marathon runners retinopathy described in runners (6). Running usually augments the fibrinolysisn and coagulation cascade equally in normal individuals. Runners who develop venous occlusive disease have a prothrombotic state due to augmented coagulatory activation and dehydration.

Neuro-Opthalmic Problems (Pupils, Diplopia, Vision loss, Papilledema)

At the 1974 Boston Marathon, Kenneth Myers found that visual function tests such as accommodation, stereopsis, near phorias, and peripheral fields were not affected by systemic fatigue (7). We will, however, review some case reports of running-induced neuro-ophthalmic conditions.

There are many case reports of diplopia being exacerbated by running. Possible mechanism for this include decompensation of existing phorias, myasthenia gravis with fatigue, increased temperature with neuronal cross-talk in demyelination (Uhtoffs phenomenon), and exercise-induced vasospasm.

Altered cerebrospinal fluid dynamics might occur with Chiari syndrome and pseudotumour cerebri, causing diplopia. Occasionally, neuroimaging of patients with exercise-induced diplopia will reveal tumors or aneurysms. It may be difficult to elucidate if the diplopia is completely attributeable to the brain lesion or it's just an incidental finding.

There are many case reports of transient visual loss with running, usually attributed to vasospasm or acephalgic visual migraine (8,9). Uhtoffs phenomenon may also cause transient vision loss. Athletes with demyelination and Uhtoff's phenomenon may consider using cold drinks prior to and during exercise, avoiding dark clothing, and using evaporative cooling garments.

It has been reported that the endogenous opiates released during running may cause smaller pupils, i.e. miosis in both eyes, after running (10). If only one pupil is smaller after running and there is an ipsilateral ptosis, facial pain, and perhaps decreased facial sweating, Horner's syndrome from internal carotid artery dissection should be suspected (11). Internal carotid artery dissection is a potentially life-threatening condition that has been described after numerous activities including neck manipulation, running, and even sneezing. Some patients can have retinal or cerebral ischemia during the first two weeks following carotid dissection, if antithrombotic treatment is not initiated.

Papilledema in association with marathon running has been described from cerebral venous sinus thrombosis (12). A case report of a 30-year-old man who died from brainstem herniation and papilledema after a marathon (13) described the patient as collapsing at the finish line. He was then treated for a post-marathon hyponatremia of 133-Discussion with the patient's widow revealed he had symptoms of subarachnoid hemorrhage three months prior to the marathon but continued with marathon training. On race day, his incompletely recovered cerebral edema from subarachnoid hemorrhage was exacerbated by hyponatremia and/or intravenous rehydration with one litre of 5% dextrose and one litre of NaCl. The authors indicated how difficult it would have been to elucidate this patient's underlying problem because of the symptom overlap of hyponatremia and increased intracranial pressure (e.g. vomiting and lethargy). The authors suggest, however, that fundoscopy might have been the most useful diagnostic test to identify the patient's need for urgent neuroimaging.

Return to Running After Eye Injury

As exemplified by the last case report, marathon runners will persist in running even when severely injured. It was difficult for me to find any evidence-based articles concerning return to running after eye surgery.

The following are only guidelines and patients must accept that return to running before six weeks post-operatively carries some degree of risk. Most of the LASIK surgeons I talked to advise patients to resume running one to three weeks after LASIK surgery. If patients are running on trails or in heavy traffic, protective eye wear should be used.

Following cataract surgery, there is a potential risk that finger rubbing against the cataract wound might cause endophthalmitis. If there is instability of the lens zonules, perhaps lens dislocation might also occur. In patients with older style plate haptic intraocular lenses, running immediately after YAG laser capsulotomy is not advisable.

After delicate retina surgery, waiting four to six weeks before running is advisable. If there is an intraocular gas bubble tamponade, flying to a marathon event can be a potential risk for gas expansion, although most commercial flights have pressurized cabins.

Most retina surgeons have not indicated to me that running causes retinal detachment. The incidence of retinal detachment has decreased even though the number of runners has increased over the last few decades. Some runners with retinal detachment in one eye worry about the risk of contralateral involvement if they continue to run. Practically speaking, retina surgeons routinely examine and treat the contralateral eye if there are areas of weakness in the contralateral retina. Obviously if a runner notices worsening of flashes or floaters, or field loss while running they should stop running and have their eyes dilated and examined.

Opthlamic & Visual Considerations in Injury Prevention

Running is in general a safe sport. Ocular surface injuries usually result from trauma with tree branches. Runners exercising along roadways are rarely subjected to injury from intraocular foreign bodies (15). Running alone at night is a potential risk factor for unprovoked attacks which may involve the eye and face.

The biggest health risk to runners is injury from motor vehicle collisions. The Road Runners Clubs of America recommends keeping the "eyes up" when running, high visibility running gear, and maintaining eye contact with drivers who are stopped. Studies on visual perception suggest that the biological running motion of reflectors on the extremities increased visibility three times, compared with light-colored clothing (16). Runners wearing lights may be seen in dark of night at distances as far away as 800 m, whereas reflective clothing with biological motion was detectable at 400 m. Brightly colored yellow or orange clothing might be detected at 137 m which is usually better than the threshold of a drivers braking time on most roadways (17). White t-shirts were only seen at 15 m, well below the threshold of stopping safety. White t-shirts were only detected slightly better than dark running apparel.

Visually Handicapped Runners

Legal blindness is defined as acuity less than 20/200 in the better seeing eye, or visual field less than 20 degrees in both eyes. A normal monocular visual field extends 170 degrees horizontally and 130 degrees vertically. The U.S. Association of Blind Athletes classifies blind runners in three categories B1-B3, with B1 being the most visually impaired (18). The Boston Athletes Association groups all blind runners in one race category. At the Boston Marathon, running guides are allowed for B1 and B2 athletes. These guides can verbally guide their charges or run with them on a tether, or their elbow. In crowded marathons, if the rules allow a longer tether, some advocate that the guide should wrap the tether around their chest or waist with the blind runner in tow. The guide then only needs to find a single-width path for the blind runner. The blind athlete should only hold the tether between their digits, rather than wrapping the cord around their wrist/fingers, to avoid sprains or dislocations. The aid stations are particularly difficult for blind runners to negotiate, as one might imagine.

In summary, many conditions can affect the runner's eyes, and awareness of them will decrease the risk of injury and enhance enjoyment of sport.

REFERENCES

(1.) Ing E. Sun safety in children. Can J Ophthalmol 2009: 44(4):e31.

(2.) Konstantinos N. Asouhidou I, et al. Aerobic exercise and intraocular pressure in normotensive and glaucoma patients. BMC Ophthalmol 2009: 13(9):6.

(3.) Williams PT. Prospective epidemiological cohort study of reduced risk for incident cataract with vigorous physical activity and cardiorespiratory fitness during a 7-year follow-up. Invest Ophthalmol Vis Sci 2009: 50:95-100.

(4.) Williams PT. Prospective study of incident age-related macular degeneration in relation to vigorous physical activity during a 7-year follow up. Invest Ophthalmol Vis Sci 2009; 50:101-106.

(5.) Gale J, Wells AP, Wilson G. Effects of exercise on ocular physiology and disease. Surv Ophthalmol 2009; 54(3):349-55.

(6.) Labriola LT, Friberg TR, Hein A. Marathon runner's retinopathy: case report. Semin Ophthalmol 2009: 24(6):247-50.

(7.) Myers KJ. Marathon running and vision. Am Optom Assoc 1976; 47(4):515-20.

(8.) Imes RK, Hoyt WE Exercise-induced transient visual events in young healthy adults. J Clin Neuroophthalmol 1989; 9(3):178-80.

(9.) John A, Frank Dettwiler B, Fleischhauer J, Sturzenegger M, Mojon DS. Exercise-induced vasospastic amaurosis fugax. Arch Ophthalmil 2002; 120:220-222.

(10.) Macdonald DJ, McKillop EC. Carotid dissection after treadmill running. Br J Sports Med 2006; 40(4):e10.

(11.) Allen M, Thierman J, Hamilton D. Naloxone eye drops reverse the miosis in runners--implications for an endogenous opiate lest. Can J Appl Sport Sci 1983; 8(2):98-103.

(12.) MRCOphth Case Studies Neuro-ophthalmology, Case 18: http://www.mrcophth.com/pd/venousthrombosisa.htm.

(13.) Petzold A, Keir G, Applehv I. Marathon related death due to brainstem herniation in rehydriaion-related hyponatraemia: a case report. J Med Case Reports 2007; 1:186-195.

(14.) Hagan J. Running and retinal detachments: http://www.medhelp.org/user_journals/show/144150/Activity-after-Retinal-Detachment-Surgery.

(15.) Jaycock P, Poon W, Wigley F, Williamson J, Williamson TH. Three cases of intraocular foreign bodies as a result of walking or running along roadways. Am J Ophthalmol 2004: 137:585-6.

(16.) Tyrrell RA, Brooks J, Balk SA, Carpenter TL, Pedestrian Conspicuity at Night: How Much Biological Motion is Enough? Transporation Research Board Annual Meeting, Washington, 2006, Paper #06-2607.

(17.) Robbins L. Collision course. Runners World Jan. 2010: http://www.runnersworld.com/article/0,7120,s6-238-267-270-13373-0,00. html.

(18.) United States Association of Blind Athletes IBSA Visual Classifications: http://www.usaba.org/Pages/sportsinformation/visualclassifications.html.
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Title Annotation:vision problems of runners
Author:Ing, Edsel
Publication:AMAA Journal
Article Type:Disease/Disorder overview
Geographic Code:1CANA
Date:Sep 22, 2010
Words:2938
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