Rest
Maximum Accommodation
  • Used for viewing and focusing distant objects.
  • Ciliary muscles are relaxed, suspensory ligaments taut
  • Refractive power is low.
  • The lens is thin and has less curvature.
  • Used for viewing and focusing closer objects.
  • Ciliary muscles are contracted, suspensory ligaments relaxed
  • Refractive power is high.
  • The lens is thick can has more curvature.

When the Ciliary muscles are at rest the lens is thin and has low curvature. At this time the refractive power of the lens is fairly low and is therefore best suited for focusing distant objects where the light rays are travelling almost parallel and not much refraction is needed. This differed from when the Ciliary muscles are contracted and the lens becomes thicker and has more curvature to allow for maximum accommodation as there is a higher power of refraction making it more suited for closer objects where the light rays are coming from different angles and a higher amount of refraction is needed.

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Figure 5.1 represents the process occur when both the Ciliary muscles are contracted and relaxed causing maximum accommodation and rest respectively. This diagram also represents the refractive power of both lenses and their primary use.



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