Final answer:
To reduce eyestrain from prolonged focusing at one depth, practice the '20-20-20 rule,' use corrective lenses as needed, and consider eye exercises or refractive surgery like LASIK.
Step-by-step explanation:
To relieve eyestrain caused by focusing intensely at one depth of vision for long periods, it is important to regularly change the focus of your eyes from near to far distances. The eye accommodates close vision by making the lens more converging, a state in which the eye is fully accommodated. This is controlled by the ciliary muscle and can lead to eyestrain when done excessively. To help with this condition, you can practice the "20-20-20 rule," where every 20 minutes, you look at something 20 feet away for at least 20 seconds. Additionally, ensuring proper lighting, taking regular breaks, using corrective lenses if needed, and possibly considering vision therapy or eye exercises can assist in reducing eyestrain. In some cases, refractive surgery like LASIK may be an option for permanent correction of focus issues.