Workstation Lenses

Following the previous article on Visual Task Analysis, let’s turn our attention to suitable lens types for use at home, work or the office which will help alleviate some of the most common problems patients complain of in relation to Digital Eye Strain, Computer Vision Syndrome or general fatigue and eyestrain when sitting at their workstation.

Low Add Boost Lenses

“Low add boost” is the term given to accommodative support lenses which are designed to help pre-presbyopes, younger adults and students who experience difficulties with prolonged close vision tasks. These lenses have a smooth progression towards the bottom of the lens with a ‘low add’ introduced for when the direction of gaze drops typically when reading, or using a digital device. Due to the low add these lenses feel like a single vision lens to most wearers. Nearly all lens manufacturers have a lens offering in this category.

Enhanced Reading Lenses/Degressive Lenses

These lenses are considered as lenses that start off with the reading prescription in the lower part of the lens, which reduces in power by the ‘degression’ amount to give an increased working distance as the patient looks towards the top of the lens. Most are useful for intermediate and near tasks where a wide visual field is required, e.g. large PC monitor. Fitting parameters differ between manufacturers and careful consideration should be given to working distance, posture and workspace environment. These lenses should only be worn for intermediate and near tasks.

Occupational Lenses

Occupational Lenses differ from degressives in that they are more like a traditional PPL, most with soft design and a longer progression that give a wider intermediate area and slightly smaller or ‘restricted’ distance area. Most of these lenses can be ordered with different progression lengths and have a limited distance zone which gives clear vision up to 2 or 4 metres. These lenses should only be used ‘indoors’ and patients should be advised NEVER to drive in them. Patients may have a pair of occupational spectacles in addition to their general wear progressive lenses. Most lens companies offer lenses in this category.

Progressive Lenses

Many modern progressive lenses may actually be sufficient to give comfortable vision to the wearer without the need for a specific pair of ‘computer’ spectacles. Modern methods of production, including freeform surfacing, compensated powers, bespoke production by supplying additional fitting parameters enable a fully customised lens which will give the best possible visual acuity. Lens designs may also take into account eye movements, head position and even moving the bias within the lens to the intermediate zone if that is what is used most. Again, most lens manufacturers will have lenses available in this category.

There are many solutions available and with careful questioning the eyecare practitioner can tailor solutions to each patient’s needs.