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Optics and refractive errors
| Content Provider | Scilit |
|---|---|
| Author | Ahmed, Nemat Kouli, Omar Khalil, Mostafa Kousha, Obaid |
| Copyright Year | 2019 |
| Description | Axial length of the eyeball is measured from the corneal surface to the retinal pigment epithelium/Bruch membrane. The majority of axial lengthening of the eye occurs within the first 3–6 months of life. Astigmatism occurs when the refractive power of the eye is not the same in all meridians (directions) due to a change in the shape of the lens or cornea's curvature, frequently described as 'rugby ball-shaped'. Cylindrical lenses are lenses that contain a cylinder in a single plane surface, and unlike spherical lenses, they focus the light into a line rather than a point. Hence, a spherical lens has the same power in all meridians, whereas a cylindrical lens has power in one meridian only. Presbyopia refers to an age-related loss of accommodative ability of the eye. It can be either due to an increase in lens size and hardness, or due to ciliary muscle dysfunction. Book Name: The Duke Elder Exam of Ophthalmology |
| Related Links | https://api.taylorfrancis.com/content/chapters/edit/download?identifierName=doi&identifierValue=10.1201/9780429275081-2&type=chapterpdf |
| Ending Page | 32 |
| Page Count | 12 |
| Starting Page | 21 |
| DOI | 10.1201/9780429275081-2 |
| Language | English |
| Publisher | Informa UK Limited |
| Publisher Date | 2019-07-30 |
| Access Restriction | Open |
| Subject Keyword | Book Name: The Duke Elder Exam of Ophthalmology Oncology Lenses Spherical Meridians Refractive Cylindrical |
| Content Type | Text |
| Resource Type | Chapter |
