Thinking about Blindness, Risks, and Safety Trade-offs

Facing safety trade-offs through risk management


It’s time to structure my wanderings and face denial about the special problems of dangers of living with partial eyesight. This post starts a simple framework for analyzing risks and defining responses. Sighted readers may become aware of hassles and barriers presented to Vision Losers who may learn a few tricks from my experience.


Life is looking especially risky right now: financial follies, pirate attacks, natural disasters, ordinary independent activities, … A Vision Loser needs special precautions, planning, and constant vigilance. So, here I go trying to assemble needed information in a format I can use without freaking myself back into a stupor of denial.

Guiding Lesson: Look for the simplest rule that covers the most situations.

Appeals to experts and clever web searches usually bring good information, lots of it, way more than I can use. I discussed this predicament in the context of Literacy when I realized I couldn’t read the pie charts sufficiently well to understand asset allocations. I had 500 simulations from my “wealth manager”, projections to age 95, and my own risk profiles. But what I needed was a simple rule to live by, that fit these, now absurd, models, like

“Live annually on 4% of your assets”.

Another rule, one I obey, that could have saved $trillions is like:

Housing payment not to exceed 1/3 Income.

Such rules help focus on the important trade-offs of what we can and cannot do sensibly rather than get bogged down in complex models and data we can’t fully understand or properly control. If we can abstract an effective rule from a mass of details, then we might be able to refresh the rule from time to time to ask what changes in the details materially affect the rule and what adjustments can cover these changes. We can also use generally accepted rules to validate and simplify our models. This is especially important for the partially sighted since extra work goes into interpreting what can be seen and considerable guess work into what’s out there unseen.


I need comparable safety rules to internalize, realizing their exceptions and uncertainty. Old rules don’t work too well, like “Look both ways before crossing the street”. also listen, but what about silent cars. Or “turn on CNN for weather information” if I can’t read the scrolling banners.

Background from Software risk management


When I taught software engineering, the sections on project management always emphasized the need for Risk Management in the context of “why 90% of software projects fail”. This subject matter made the basis for a good teamwork lab exercise: prioritize the risks for a start up project. I dubbed this hypothetical project Pizza Central, a web site to compare local pizza deals and place orders, with forums for pizza lovers. Since all students are domain experts on both pizza deliveries and web site use, they could rapidly fill out a given template. Comparing results always found a wide divergence of risks among teams, some focused on website outage, others on interfaces, some on software platforms. So, one lesson conveyed among teams was “oops, we forgot about that”. My take-away for them was that this valuable exercise was easy enough to do but required assigned responsibilities for mitigating risks, tracking risk indicators, and sometimes unthinkable actions, like project cancellation.


I am about to try a bit of this medicine on myself now. Risk is a complicated subject, see Wikipedia. I’ll use the term as “occurrence of a harmful event” in the context of a project or activity. The goal is to mitigate both the occurrences and effects of these nasty events. But we also need indicators to tell when an event is ongoing or has happened. Since mitigation has a cost of response both to prevent and recover from events, it helps to have prioritization of events by likelihood and severity. So, envision a spreadsheet with event names, ratings for likelihood, severity, and costs, perhaps with a formula to rank importance. Associated with these events are lists of indicators, proposed mitigation actions with estimated costs. This table becomes part of a project plan with assigned actions for mitigations and risk tracking awareness across team members as a regular agenda item at project meetings..

Risk analysis for my workout/relaxation walk


I will follow this through on the example of my daily workout walk. I do not use my white cane because I feel safe enough, but really, is this a good tradeoff? Without the cane, I can walk briskly, arms swinging, enjoying shadows, tree outlines, and the calls of quail in the brush. The long white cane pushes my attention into the pavement, responding to minor bumps and cracks my strides ignore, and there’s even a rhythm to the pavement that adjusts my pace to a safe sensation. I would not think of walking without my guiding long white cane on a street crowded with consumers or tourists but this walk covers familiar terrain at a time frequented by other recreational walkers. This situation is a trade-off unique to the partially sighted, who only themselves can know what they can safely see and do, living with the inevitable mistakes and mishaps of the physical world.

Here are a few events, with occasional ratings on a 1-10 scale. For this application, I feel it’s more important to ask the right questions, albeit some silly, to surface my underlying concerns and motivate actions.

  1. Event: Struck by lightning, falling tree, or other bad weather hazard

    <Indicators<:Strong winds, thunder, glare ice

    <likelihood<: 8, with walks during

    <Severity<: 9, people do get whacked

    <Mitigation Actions and costs:<

    • -7, look for dark clouds. but Can’t see well enough in all directions over mountains
    • 0, Listen for distant thunder, also golf course warning sirens
    • -1, check CNN and weather channels, but hard to find channel with low accessibility remote and cable box, also reading banners and warning screens not always announced. FIND RELIABLE, USABLE WEATHER CHANNEL, ADD TO FAVORITES
    • Ditto for Internet weather information, but I never am sure I am on a reliable up-to-date website or stream, especially if ad supported
    • Ditto for Radio, using emergency receiver. ACTION: set up and learn to use.
    • For ice patches, choose most level route, beware of ice near bushes where sunlight doesn’t reach for days after a storm, walk and observe during afternoon melting rather than before dusk freezing

    Summary: I should keep emergency radio out and tuned to a station. ACTION needed for other threats than weather, also.

  2. Event: Trip over something

    <Indicators<: Stumbling, breaking stride, wary passers-by

    <likelihood<: 5,

    <Severity<: 6

    <Mitigation Actions and costs:<

    • 0, Follow well-defined, familiar route with smooth pavements, rounded curbs – I DO THIS!
    • Never take a short cut or unpaved path.

    • $100, wear SAS walking shoes with Velcro tabs, NO SHOE LACES to trip over
    • 0, detour around walkers with known or suspected pets on leashes, also with running kids or strollers.
    • 0, take deliberate steps up and down curbs, use curb cuts where available. Remember that gutters below curbs often slope or are uneven. Don’t be sensitive that people are watching you “fondle the curb”.
    • Detour around construction sites, gravel deliveries, … Extra caution on big item trash pickup days when items might protrude from trash at body or head level.
    • Detour around bushes growing out over sidewalks, avoiding bush runners, also snakes (yikes)

    Summary: I feel safe from tripping now that I have eliminated shoe laces and learned, the hard way, not to take curbs for granted.

  3. Event: Hit by some vehicle

    <Indicators<: Movement, perhaps in peripheral vision; noise

    <likelihood<: 5

    <Severity<: 7

    <Mitigation Actions and costs:<

    • 0, stay on sidewalks, if not overgrown by brush
    • 1, walk when others are out and about, expecting auto and bicycle drivers to be aware
    • find a safe, regular road crossing, away from an irregular intersection, and jay walk. Is this wise?
    • Do not walk at times of day when sun may blind drivers, e.g. winter days when sunsets are long and low
    • Do not trust ears. Bicycles are quiet on smooth pavements, move rapidly down hill. Also hybrid cars may run silently.
    • Halt completely when in the vicinity of noisy delivery trucks or car radios. Blending hearing and seeing requires both be at maximum capacity.
    • Remember that eerie white cross memorial indicating a dangerous intersection with cars coming around a blind curve and often running stop sign. Also shout at speeders and careless drivers.
    • REJECTED: Use white cane to warn others I’m limited at seeing them. I don’t think the white cane adds more warning than my active body motion.

    Summary: I am currently using 3 safe routes, must not let mind wander at each intersection and crossing. ACTION: sign a petition for noise indicators on silent motors.

  4. Event: Getting lost

    <Indicators<Unfamiliar houses, pavements, in intersections

    <likelihood< 1,

    <Severity<: 1

    <Mitigation Actions and costs:<

    • Follow same routes through established neighborhoods
    • $1000, get GPS units and training. Consider when I move and need to define new walking routes.
    • Beware or boredom to tempt alternate routes.

    Summary: I used to get lost, turned around in neighborhoods, no longer take those excursions. 3 regular walking paths will do.

  5. Event: Cardiac attack

    <Indicators<: frequent stops, pain, heavy breathing

    <likelihood<: Hey, that’s why I do these walks, to build breathing stamina at an altitude of 5000 ft with several serious up and down hill stretches.

    <Severity<: Something’s gonna get me, hope it’s quick.

    <Mitigation Actions and costs:<

    • Exercise regularly to maintain condition.
    • Checkup when Medicare allows and physicians are available (thanks U.S. health care system)

    Summary: Not to worry as long as walks feel good.

Risk Management Summary

I choose this walk as my primary exercise activity, have integrated it into my daily routine, and generally feel better as well as safe. Eliminating shoe laces removed a major stupid cause of minor stumbling and potential falls. I have avoided unsafe and confusing trajectories. My main fears are: Fedex or UPS delivery trucks, fast downhill bikes, pet greetings, loose children, persistent brush-hidden ice patches. My cane would, in this environment, change attention from moving objects toward pavement which is smooth and uncluttered. The cane would do little to warn off threats — they either notice me or not. I choose to balance my partial sight used cautiously with improving listening skills and opt to walk faster and more comfortably without the leading cane and its frequent catches in cracks and grass.

Actions: While walking may not be the main reasons, I must gear up with that emergency radio for other threats. More generally, I must learn about emergency information sources that fit my vision capabilities.

References on Risks

  1. Wikipedia on Risk
  2. How to for risk management
  3. Risks to the public using software, decades of examples of software-related events and management as risks
  4. ‘Nothing is as Simple’ blog, a phrase to remember and examples
  5. Previous post on Literacy and reading charts, how I discovered I couldn’t read pie chart data
  6. Previous Post ‘Grabbing my Identity Cane to Join the Culture of Disability’. I have now progressed through orientation and mobility training to using a longer cane with a rolling tip.
  7. Emergency preparedness checklists for Vision Losers — TBD
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2 Responses to “Thinking about Blindness, Risks, and Safety Trade-offs”

  1. horning94301 Says:

    One additional consideration for ice patches (remembered from my days in a cold climate): Water tends to puddle in nearly flat areas, and even sighted persons often fail to notice it and slip on “black ice.”

  2. Lessons from 2008 ‘As your world changes’ « As Your World Changes Says:

    [...] As Your World Changes Adjusting to vision loss with class, using technology « Thinking about Blindness, Risks, and Safety Trade-offs [...]

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