Visual Impairment

VISUAL IMPAIRMENT

– Written by Ciro Winckler and Andrea Jacusiel Miranda, Brazil

AETIOLOGY para athletes. This difference is due mainly with VI are divided into three sporting Visual impairment (VI) is caused by to the mean age of competing athletes classes. The minimal disability criteria to impairments to the ocular globe, optical as well as world regions for which para be eligible for participation in para sport is nerve or visual cortex, resulting in a sport is highly developed. Socioeconomic based on the American definition of legal functional limitation in the interaction development, the availability of primary blindness (visual acuity in 20/200)5. of the person with the environment. This healthcare and eye care services highly The current classification system is impairment can be divided into blindness determine the frequency with which these based on factors related to both visual and low vision, according to the degree of pathologies are recognised according to acuity and visual field (Table 2). While this remaining vision. Blindness encompasses each region2. classification system is based on biomedical the spectrum from complete vision loss concepts only, there is a great demand for to the perception of light and colour, but PARALYMPIC SPORTS adjustments to be made so that there is in a non-functional condition for motor The history of sport participation by an evaluation of the visual functionality learning. Low vision is defined as the ability persons with VI dates back to the beginning applied to each sport7. to perceive light, colour and form, but has of 20th century in athletics events, baseball Unique characteristics of the Paralympic limitations in the perception of space, and gymnastics taking place in the United classification system for athletes with VI are details, movement, three-dimensional and States3. Today, athletes with VI compete in noted in Table 3. Indeed, each Paralympic compound shapes1. the summer Paralympic sports of athletics, sport varies with regard to type of support It should be noted, of course, that there cycling, equestrian, football 5-a-side, goalball, offered to athletes with VI. In some sports are notable discrepancies between the judo, rowing, swimming and triathlon, as the athletes compete only in their sport class prevalence of various aetiologies of visual well as the winter sports of alpine skiing, and, in others, they compete in a single class impairment in the general population versus biathlon and cross country skiing4. Athletes (all classes together). Additionally, in some

138 Table 1

Main Etiology Characteristics Relevance to para athletes

1 Cataract Accounts of 51% of blindness globally (2010) Very commonly found among para athletes

Onchocerciasis (river As para sport in Africa continues to increase it 2 Seen most frequently in the African region blindness) may be seen more frequently Etiologies include vitamin A deficiency, rubella, 3 Childhood blindness cataract, retinopathy of prematurity, congenital Very common abnormalities Refractive errors and Etiologies include myopia, hyperopia with or Many of those affected are not eligible in VI 4 low vision without astigmatism functional classification Noted in individuals with chronic diabetes 5 Diabetic retinopathy Very uncommon mellitus Group of diseases with optic neuropathy as a High ocular pressure demands special medical 6 Glaucoma common endpoint attention in sport Age-related macular 7 Condition affecting older individuals Very uncommon degeneration Encompasses wide variety of infectious and Very commonly seen in para athletes, due to 8 Corneal opacities inflammatory eye diseases that scar the cornea many different and often uncommon eye diseases Since athletic performance also has a hereditary Ocular pathologies transmitted from parents to 9 Genetic eye diseases component, it is not unusual to find in para children by genetic inheritance athletes’ siblings Table 1: Most common etiologies of visual impairment globaly2.

sports, blindfolds are utilised to completely obscure the vision (and ensure equal level of Table 2 impairment) for all athletes, such as the B1 class, or for all athletes during competitions with combined classes. Impairment Class Range of Visual Function Finally, some sports allow for an escort- athlete such as a guide or pilot to assist Blindness B1 Visual acuity poorer than LogMAR 2.6. the athlete with VI. The function of the guide or pilot is to support the athlete in Visual acuity ranging from LogMAR 1.5 to 2.6 (inclusive) their limitation – visual orientation of the Low Vision B2 and/or visual field constricted to a diameter of less than 10 degrees. environment. For example, in the sport of athletics, the role of the guide is to run Visual acuity ranging from LogMAR 1.4 to 1.0 (inclusive) together with the athlete at the same pace, Low Vision B3 and/or visual field constricted to a diameter of less than read the environment and translate this to 40 degrees. the athlete with verbal and tactile cues. Table 2: Classification based on visual impairment in Paralympic Sports6.

CLINICAL MANAGEMENT There are several points that are not learned the socially accepted facial screen and asking questions at the same important to keep in mind when providing expressions associated with each emotion time) might be interpreted as lack of clinical care for athletes with VI. Among or with what one may want to infer, may attention. Touch can be used as a tool to the challenges facing the medical staff are it be through a smile of comprehension or better communicate, as it denotes interest two basic principles of clinical practice: a frown denoting doubt on what is being and may be used to anatomically explain empathy and communication. Nonverbal said. For this reason, when interacting an injury or better define where a pain is cues play an important role in physician- with athletes with VI, one must pay felt (always previously explaining where patient interactions, and often these rely special attention to voice intonation, both one is going to touch and having asked on visual information8,9. VI athletes are when speaking and when listening, as permission to do so10). often not able to pick up visual cues from well as one’s direction when speaking. Persons with blindness, particularly in medical staff. And for those with onset For example, not speaking directly at the congenital or early onset, may manifest of the impairment early in life, who have athlete (as when looking at a computer mannerisms15. These are repetitive

PARALYMPIC ATHLETES TARGETED TOPIC 139 VISUAL IMPAIRMENT

Table 3 behaviours or movements that do not Classes Escort/Support* Blindfold Combine appear to be directed towards obtaining a goal, for example, eye manipulation, body Athletics 11/12/13 Guide 11/12 11 rocking or flicking fingers in front of the eyes while staring at light. These are more Cycling 11/12/13 Pilot All X frequent when the person with blindness is experiencing stress or anxiety. Equestrian B1/B2 Caller B1/B2 As with all Paralympic sports, the Football physician must consider anti-doping B1 Goalkeeper B1 5-a-side regulations at all times, including which substances and methods are included on Goalball B1/B2/B3 All X the World Anti-Doping Agency (WADA) Prohibited List, as well as the impact Judo B1/B2/B3 of all prescribed substances on sports performance. Specific to athletes with Rowing B1/B2/B3 All X VI, providers must take care with use of acetazolamide and beta-blocker eye drops, Swimming 11/12/13 Tapper 11/12 11 often prescribed for glaucoma, both of Triathlon 11/12/13 Guide/Pilot All 11 X which are prohibited substances. Insulin, often prescribed for glycaemic control in Alpine Skiing B1/B2/B3 Guide B1/B2/B3 B1 X individuals with diabetes mellitus and diabetic retinopathy, is also a prohibited Biathlon B1/B2/B3 Guide B1/B2/B3 B1 X substance. Each case must be considered individually to determine whether such Cross Country B1/B2/B3 Guide B1/B2/B3 B1 X medications are ideal for treatment of Skiing the disease process, while also taking into * Support is mandatory for athletes in Class B1 or 11 however is an option for athletes in class consideration athlete performance. B2 or 12. The understanding of the VI mechanism Table 3: Characteristics of competition across Paralympic sports and classes for athletes with is fundamental as some types of exercises by VI. Class 11 is equivalent to B1, class 12 to B2 and class 13 to B3. Adapted from IPC 4. persons with specific impairments, without adjustments to the training protocol or environment, may worsen the impairment. is a condition analogous to the “phantom All of the above conditions can impact For example, contact sports such as goalball limb syndrome”16. The traditional treatment the performance, training and recovery of and judo should not be recommended approach is pharmacological intervention16. the athlete with VI. They also play a major for those at risk for retinal detachment11. Another important point to note is role when travelling to different time zones If contact sports are pursued by at-risk that athletes with no light perception (full for competition. Adjustments are necessary individuals, head protection should be used. blindness) may experience a disruption to minimise the effects on training quality In some more severe cases, jump training in their circadian rhythms18. This has the and performance. can induce retinal detachment. Precautions potential to result in: should also be taken for athletes with • Reduced peak performance, simple THE IMPACT OF VISUAL IMPAIRMENT ON diabetic retinopathy as heavy weightlifting reaction time and body temperature PHYSICAL CAPACITY dramatically increases blood pressure and regulation throughout the day19. Inherently, the presence of VI modifies may cause retinal bleeding12,13. Athletes with • Altered concentration and distribution the quantity of visual information received glaucoma require special attention during of melatonin throughout the day18. and limits one’s perception of environment. intense physical exercise, as changes in body • A delay in the prepubertal growth However, this is not only due to lack of position and increased respiratory volumes, period, especially in women20. visual information, but also due to limited especially with Valsalva manoeuvre, may • Later menarche in women21. exposure to incidental information over place the athlete at risk14. Finally, it is • Sleep disorders22. time24. Compensatory strategies are important to note that the reduced visual Furthermore, it is a challenge for B1 and necessary to minimise resultant limitations stimulus on the visual cortex may trigger B2 athletes to self-monitor hydration from in motor control and the spatial orientation. what is known as Claude Bonnet syndrome, the standpoint of urine colour and volume23. Visual impairment interferes in a which can cause visual hallucinations, most Although an imperfect measure, some significant way on the accomplishment commonly in the image of a person, and athletes use the smell of the urine as a guide, of specific aspects of performance in non- affects between 0.4 and 14% of people who since a stronger smell of urine is usually trained individuals, which differs from the lose their vision during their lifetime16,17. It associated with a higher concentration. pattern seen in trained athletes25. With

140 Figure 1: The Impact of Visual Impairment on Physical Capacity. It is important to note that persons with VI may achieve similar physical performance to that of persons without VI when provided 39 Athlete with exposure to proper training . I

Performance Skill

• Technical differences • Incidental learning associated with visual privation24 classes26 Aerobic • Limitation in • Speed associated with spatial skill8 jump capacity27,28 alance an anaerobic • Low coordination and • Performance associated high fatigue in exercise37 with visual capacity29,30,31 resistance • Performance association between athlete with VI • Lower performance32 • Similar in uence of 27 and guide • Balance associated training in VI and NoVI35 with visual acuity level33 • Training improves reduction • Adjustments of balance Strength of fatigue index36 32 strategies • VO2 associated with visual classication37

• Similar performance of maximal strength in VI and NoVI34 • Limited performance I Athletes I of power in VI34 NoI Athletes ithout I this notion as a starting point, Figure 1 explains the higher incidence of lesions Acknowledgment provides a summary of the pattern of motor of the feet and legs that occur during The authors wish to extend their deepest responses observed in athletes with VI and daily activities in VI athletes, not directly gratitude to Brazilian Paralympic Academy/ how it is related to the development of related to sports23. Additional evidence APB and National Counsel of Technological physical abilities in this population. reveals that the greater the VI, the higher and Scientific Development/CAPES/Brazil the prevalence of injury in an athlete INJURY EPIDEMIOLOGY population43. This can be related to the Recent evidence demonstrate higher fact that postural stability is affected injury rates in athletes with VI that compete by vision and proprioception in blind in summer sports. At the 2012 Summer individuals tends to be worse than in those Paralympics Games the highest injury with partial vision resulting in abnormal References available at incidence rates was found in football gait and biomechanics, which can lead to www.aspetar.com/journal 5-a-side, followed by powerlifting, goalball, injuries43. wheelchair fencing, wheelchair rugby, athletics and judo1. Of the seven sports with CONCLUSION AND PRACTICAL the highest injury incidence rate, three APPLICATIONS were practiced exclusively by athletes with Although the presence of VI may impact Ciro Winckler Ph.D. VI and a fourth (athletics) is inclusive of all the performance of the athlete, sport-specific three VI classes. training and excellence in sports medicine Sport Science Coordinator, Brazilian In general, injuries to the lower limb, services may be helpful in mitigating any Paralympic Committee followed by the upper limb, were more detrimental effects. This process is guided Professor, São Paulo Federal University frequent in athletes with VI40,41. Acute by knowledge regarding the aetiology of VI São Paulo, Brazil traumatic injuries were particularly as well as its consequences on short- and prevalent in football 5-a-side41,42. This may long-term performance. From a practical Andrea Jacusiel Miranda M.D. be related to the VI, making athletes more standpoint, it is fundamental in this process vulnerable to bump into other players to provide excellent spatial orientation, Medical Doctor, Brazilian Paralympic Committee (with lack of a protective reflex), barriers adequate stimulation and an efficient in the training and competition area or channel of communication with sports objects on the field41. The same rationale medicine providers. Contact: [email protected]

PARALYMPIC ATHLETES TARGETED TOPIC 141