The Use of an Infrared Eye Tracker in Evaluating the Reading Performance in a Congenital Nystagmus Patient Fitted with Soft Contact Lens: A Case Report

This chapter reports the use of an infrared eye tracker in providing more objective and quantitative results in evaluating the reading performance of a congenital nystagmus subject. A 14-year-old boy was fitted with silicone hydrogel contact lens to correct his high refractive errors. His distance visual acuities were 6/19 (both spectacles and contact lens), and his near visual acuity improved from N10 with spectacles to N8 after 10 weeks of wearing the prescribed contact lens. His reading speed doubled from 44 to 105 words per minute (wpm) with contact lens. The improvement in reading speed was consistent with the eye movement recording results which revealed the staircase eye movement pattern, typically found in individuals with normal vision. Furthermore, his mean fixation duration during reading was found to be longer with contact lens compared to wearing spectacles.

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