One of my patients is 36 years old. He doesn’t need spectacles for distance but complains of visual discomfort and headaches with sustained near work. He works in an office with computers and paper documents. He doesn’t have any signs of a binocular vision anomaly and his amplitude of accommodation is around 7 dioptres. What is going on?
This sounds like emerging presbyopia.
We often think that presbyopia appears suddenly, at around the age of 40 years old.
But accommodative decline associated with presbyopia happens gradually throughout the lifetime. Between 20 to 40 years of age, accommodative amplitude decreases by approximately 5.00 DS. People may experience fatigue after periods of near work or find it uncomfortable to sustain near work.
Your patient may be measuring 7 dioptres of accommodative amplitude in your consulting room but he won’t be able to sustain this during his time in the office. He may manage to sustain 2-3 dioptres.
Ill-sustained accommodation is often the cause of asthenopic symptoms in emerging presbyopia. Consider fitting symptomatic, emerging presbyopes with a multifocal contact lens. Sadly, only about half of presbyopic-aged contact lens wearers use a multifocal contact lens.
Interestingly, symptomatic contact lens wearers approaching presbyopia (age 30 to 35 years) have been shown to benefit from the visual comfort offered by multifocal contact lenses. Sustained comfortable near vision is often enough to get the person through the adaptation period whereby they adapt to slight distance blur and glare around lights.
If a patient is approaching presbyopia and reporting visual discomfort symptoms due to accommodative fatigue, consider trialling a low-powered multifocal soft contact lens.