Most patients choosing a pair of sunspecs will do so based on the look of the frame alone. They will not normally consider the lens type umprompted, apart from maybe the colour of the lenses. So how can you advise a patient on the most suitable protection from a pair of sunspecs?
When advising a patient on sunspecs, the first question to ask is: “When will you be wearing them?” You can then also enquire as to whether they are for use in this country only, or for travel overseas? Ask whether they drive; or if they use their sunspecs by the water. Do they participate in water sports, or other hobbies that involve water? Do they play any sport? Do they cycle? Do they go on winter holidays, for example, skiing? The reason for all the questions is that different tints are available for a variety of different uses, and it is important to provide your patients with the best advice.
Firstly, the frame must be a good fit. If it is continually slipping forward and the patient is looking over the top of the frame, the eyes will not be adequately protected. Check the side length is correct and not too long or short. Ensure the frame is not too tight against the sides of the head as this will force the frame to slip forwards.
Similarly, check the frame is not too wide as it will then be loose. Check the bridge fitting; ideally, the eyes should be fairly central in the frame. The upper rim needs to be above the upper lid and above the eyebrows; it also needs to be close to the forehead to ensure no light can come through the top of the lens.
For sunglass use, we are mainly concerned with protecting the eyes from UV or infra-red (IR) radiation. IR radiation is present when the temperature is very hot, and so someone who spends a lot of time in an equatorial country, for example, should protect their eyes from IR radiation.
Most lenses we use in practice are made from plastic material, as they are lighter and safer than glass. Plastic lenses can be dip dyed in a tint bath to more or less any colour, and will include a UV filter so the eyes are protected from UV radiation.
Plastic lenses can also be polarised, and these lenses are very effective at cutting out reflected glare, for example, bright sunlight reflecting off a wet road. Care is needed, however, when driving in polarised lenses as they can blank out detail on digital screens such as Sat Navs and Heads Up displays. They are very effective when looking at water as they eliminate the reflections, enabling the wearer to see clearly through the water. In fact, they are often banned in fishing competitions as they give the wearer an unfair advantage as it makes seeing the fish much easier.
Photochromic lenses also offer UV protection, and they have the advantage that they can be worn all the time without the need to swap to a separate pair of sunspecs.
In conclusion, it is evident that not all sunspecs are the same. In next month’s OA Corner, we will look at sun protection for recreational use and winter sports.
Sue Deal FBDO R is a practising dispensing optician, ABDO College examiner, senior tutor and supervisor for dispensing opticians. She is also a practice visitor and external moderator for ABDO. She was recently awarded the ABDO Medal of Excellence for her outstanding services to the profession.