Field and test information
To date, winter has been very mild (the eighth warmest January on record, here in New York State). Daytime temperatures have been as high as 60 F (16 C), down to perhaps 15 F (-9 C). There has been a fair amount of snow in the mountains, but also (unusually) January rains, even at elevation. The Costa Del Mar sunglasses have been used while hiking, snowshoeing and cross-country skiing. Elevations were from 500 ft (152 m) to 4000 ft (1219 m), sometimes in heavily wooded settings.
Product Use and Performance
I remain extremely pleased by the performance of the Fathom sunglasses, which have recently accompanied me on everything from trips to the stores to difficult snowshoe ascents, here in the Catskills and adjacent areas. In cold temperatures, I have found them fairly resistant to fogging, an important consideration for winter use. I've worn them briefly under ski goggles, and the combination (at least with the goggles I use, which have a soft flexible rim) is an effective one on those days that combine glare from the snow with bitter cold and high winds. Sadly, such episodes have so far proved a rare commodity this winter.
When cross-country skiing, I did find that more light from the low winter sun entered at the top of the frame than was wholly desirable. This may have been accentuated by my skiing stance. Otherwise, I have felt throughout this test that the coverage provided by the lenses on the Fathom sunglasses is adequate. I wouldn't have minded a slightly larger lens, or an extension of the frame to minimize light leakage from above, but these design components are not really required. The sunglasses, in almost all circumstances, perform admirably. However, Costa del Mar does offer a wide range (forty-odd) of styles, and my preference for a larger lens could certainly be accomodated with another frame. Fit itself is not an issue (the glasses showed little or no tendency to migrate from their position on the bridge of my nose); coverage is more a question of the style of frame chosen.
The reduction in glare is more than adequate. Winter, with its reflective ice and snow, can be a hard season on the eyes, especially when there's bright sun in the mountains. The lenses perform extremely well in these conditions, with minimal distortion of color. The enrichment of color vision I noted in my earlier reports is less evident, simply because the palette of winter lacks the rich greens of late summer and the reds and yellows of autumn.
The lenses continue to show no scratches that I can see. Although I have treated these glasses well, they have not been babied. They have accompanied me on bushwhacks, and have deflected a few branches, so this argues that the outer surface of the lens is moderately tough. As I noted in the Field Report, the inner surface of the lenses seem to mark easily, with fingerprints and traces of skin oils showing as iridescent smudges. Though this may be evident on close inspection, when the glasses are in use there's generally no noticeable smudging in the field of view, unless the soiling is quite bad. All of the surface coatings appear to remain intact. The frames show no evidence of wear or other damage (then again, unlike my reading glasses, I haven't sat on these yet).
Referring to my original test plan, I can now address almost all the issues I raised.
Question 1. Effectiveness. First, how well do the glasses cut glare in the yellow portion of the spectrum that they are intended to block? Fifty percent of incident light in this range is eliminated, according again to the product literature. I'll test this claim subjectively (snow and water are both tough mediums for sunglasses). Wearing them, I'll not only be gauging residual glare and any resulting eye fatigue, but the quality of color created by the light that is transmitted through the lens. Are certain portions of the color range distorted? Are the colors of leaves and flowers affected (as an amateur botanist, an issue of interest to me)? Do the lenses actually improve the quality of visual experience, as claimed? Do the glasses mask natural navigational cue such as shadows? This sounds like a minor issue, but I've found that some sunglasses definitely interfere with the sort of subliminal checking that most hikers do as they walk, especially off-trail.
Answer 1. Not only is glare hugely reduced, but color is definitely accentuated in a very positive manner, though without significant distortion other than the slight tint of the lens. If anything, navigational cues seem to be clearer wearing these, and my perception of the natural world is heightened.
Question 2. Utility. Often when hiking, I will move from sunny, open spaces to deep shade. Is it necessary to remove the glasses under such conditions, or does the world still seem bright enough? Do the sunglasses interfere in any way with viewing the various gizmos (altimeter, GPS, compass) that I sometimes use when hiking? How about map-reading? Do they work well in conjunction with a magnifying lens when sorting out small details of terrain etc. on a topo map? Are contour lines etc. easily read?
Answer 2. Because of the very slight tint, I have been able to wear these glasses almost to twilight. Indeed, I tend to forget I have them on. Map and instrument reading are unaffected, as is the use of a magnifying lens.
Question 3. Comfort. Though I have worn the frames for only a couple of hours, and have found them comfortable and attractive, that's a big difference from wearing them all day on a hike or backpack. Does the design of the frame keep the glasses correctly positioned on the face during intense physical activity, such as scrambling? Is the design of the frame such that the lenses can "breathe" and avoid fogging with sweat or ambient moisture? How well do the frames wrap my face; is there light visible at the periphery of vision. Am I able to push my sunglasses on top of my head when not needed and have them stay (my usual storage area for both reading and sunglasses when not in use over the day)!
Answer 3. The frame sits quite snugly, even when cross-country skiing or scrambling. Ideally, I would like a little more shielding of incident light from above, but this is generally not a terribly significant concern. The lenses don't easily fog, as a general rule; when they do, it is in predictable circumstances (cold glasses carried into a warm car, for example). They sit well enough on top of my head if I want to put them there, but given the potential fragility of the glass lenses, I tend to tuck them away. I like this pair of sunglasses too much to risk breaking them.
Question 4. Materials. Are the lenses resistant to scratching and wear (a very important point)? Are the co-injected composite nylon frames tough enough for the rigors of intense activity? Is there any tendency for them to distort (loosen up) over time? I've not worn nylon-framed glasses of any kind before. Will they withstand my klutziness, the occasional drop?
Answer 4. The lenses have resisted scratching. I've dropped the glasses a couple of times, without causing damage, although no great distance, and not on rock. The frames remain tight, and they continue to hug my face well.
Summary
These sunglasses are perhaps the best I have worn, although I can't claim vast experience. They enhance perception of the natural world to a surprising extent, and I have felt none of the low-light blues that I've experienced with heavily tinted shades. Since the main reason I'm out is to enjoy my surrounding, this is a huge plus. They are comfortable, can be used at low levels of illumination (so I don't feel that I've been plunged into darkness when passing though heavy woods), and I've found them an absolute pleasure to wear.
