Tayyaba Ayub, Mukhtar Hussain, Muhammad Akhtar, Mehran Hassan Aizaz.
Effect of Pinhole Size on the Improvement of Visual Acuity in Relation to the Level of Ammetropia.
Ophthalmol Update Jan ;15(4):348-50.

Background: Vision is a broad term used for one`s ability to perceive an object`s shape, colors and its fine details. The maximum perfection in one`s vision, is be able to gain maximum correction of refractive errors by using lenses and pinhole is an estimation by the eye care practitioner. It can be taken as a tool for the improvement of central vision in a person having refractive errors without any other pathology. To make the image more clear, sharp and defined we need to make pinhole size smaller so as to gain the phenomenon of diffraction that allows only central ray to pass through the nodal point.. Objectives: To check the variations in the visual acuity of different types of refractive errors by changing the size of pinhole. Method: It was an observational study involving the use of structured performa. A total of 200 adult patients, 100 males having refractive error more than �1.00D and 100 females also having refractive error more than �1.00D were checked by various sizes of pinhole and their visual acuity taken with three i.e. 0.50mm, 1.00mm and 1.50mm of pinhole diameter is compared. Results: Results shows that young patients with low refractive errors show better visual acuity with smaller size of pinhole while the patients with higher error or any opacity gave better visual acuity with larger size pinhole 1.50. Conclusion: In normal individuals with low refractive errors the visual acuity is better improved with 0.5mm and 1mm while the individuals with high error give better vision with larger sizes pinhole i.e. 1.50mm.

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