Contact lenses are only desired by and required for the younger patient. In an aging population there are new challenges as contact lens practitioners where we can apply the benefits of silicone hydrogel lenses. This type of lens will become increasingly common, and to the benefit of both practitioners and patients. The dry eye syndrome often associated with the elderly becomes less significant with these lenses.
In this case study, I present my patient GB, born 1928 (age 78), who was originally fitted with haptic lenses in the 1950s, refitted with PMMA corneal lenses during the 1960s, was refitted with gas permeable lenses in the 1980s, then changed to conventional hydrogel lenses in the 1990s “for social wear only”. I first saw her in 2000 when she was 72. At that time she expressed her dissatisfaction with her then current contact lenses, especially since she had to use reading spectacles over the lenses. She particularly detested spectacle wear, perceiving it as a sign of infirmity!
Her refraction and visual acuities were:
OD +3.75/-0.25x170 6/6+
OS +4.50/-0.50x90 6/5- Add 2.25 N5
At her first visit, I prescribed conventional hydrogel progressive lenses R/ +5.00 L/ +6.00, with which she achieved 6/6 binocularly and N6. However she was only able to wear these lenses for a little more than 6 hours per day, and by 2003 stopped wearing them because they irritated her. I tried changing her care solutions, without success.
Slit lamp findings were unremarkable at all visits except that she exhibited a poor tear film with considerable conjunctival folding. Despite 50 years of contact lens wear, her corneas were remarkably healthy. I suggested that the patient may have reached the end of the road of contact lens wear. Her previous experience with rigid lenses precluded these, as adaptation problems may have been insurmountable for this patient. I then mentioned the new silicone hydrogel lenses to the patient, and she was very keen to try them, despite there not being a varifocal option (at that time).
The patient was very keen to try silicone hydrogel lenses on a flexible wear basis, this being a perceived benefit to offset having to use reading glasses while wearing contact lenses. GB is a keen birdwatcher and the compromise of monovision would be unacceptable to her. I prescribed 8.60 R/ +3.75 L/ +4.50 to be worn for six days continuously, then cleaned and left out overnight.
Her comments when I saw her one week later was that her vision was fine (R/ 6/6- O/R +1.00 6/5- L/ 6/5- O/R +0.50 6/5), but the comfort was “marvelous”. She exhibited no redness and her eyes “felt good”. Her eyes did feel tired late evening, but she had minimal blur on awakening. The slit lamp examination revealed no corneal oedema, an excellent fit. Her lenses were changed to 8.60 R/ +4.75 L/ +5.00, and at the three month check GB reported none of the tiredness at the end of the day and was extremely happy with the lenses.
GB’s life is enhanced by these lenses. She can sit in her conservatory and watch birds through her binoculars, and otters playing in the pool below her window. She uses comfort drops as and when necessary, and whilst she uses her lenses for one week extended wear, she varies this according to how her eyes feel, sometimes wearing them for more than a week, and removing them if she feels less than well.
This happy situation continued until she came in to see me for a routine contact lens check in April 2005, when the acuity in her left eye had dropped to 6/24-. The anterior eye and contact lenses were normal, but ophthalmoscopy and a retinal photograph revealed a massive retinal haemorrhage, for which she was referred for opthalmological investigation.
I last saw this patient in February 2006, when she was still wearing the lenses. Her vision in her left eye remains 6/60, but she accepts this as an inevitability of old age. A remarkable lady!
Discussion
We have an aging population. In 2000 the over 60s represented 10% of the world population, but by 2050 they are predicted to reach 22.1%, and by 2100 28.1% [1]. Many of these people have worn various contact lenses for decades, in a variety of modalities. It is our challenge to use lenses that enable such patients to continue in comfortable and safe contact lens wear. These patients will often have corneal changes that may be attributed to previous contact lens wear, but have persisted in wearing contact lenses. Their corneae are basically resilient, and despite the changes in ocular tissues associated with age, are often fundamentally healthy.
Dryness is still one of those major changes in the aging eye, and it is here that silicone hydrogel lenses can offer benefits. The reduction in water loss from the lens, may be the reason for better ocular health and lens comfort. It may also be the case that with the loss of manual dexterity associated with the aging patient, flexible wear options become desirable. Viewed holistically, an older person with better vision at night is at a lower risk of trips and falls - these may be life-threatening for that individual.
A multifocal silicone hydrogel lens is due for launch in the UK shortly, and it is hoped that this will further enhance the usefulness of these lenses for older patients.
The dry eye symptoms of the older patient can be effectively managed by the use of comfort drops, and this will further enhance their contact lens comfort. Although the lens insulates the cornea, dessication of the exposed conjunctiva may be the cause of mild discomfort. However, this should not be confused with solution toxicity reactions (see Detecting solution incompatibility: a case study).
References
- Long range world population projections: Based on the 1998 revision. The population division, department of economic and social affairs, United Nations Secretariat.
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