Entoptic Phenomenon of Intraocular Lens

**53**

better).

**Chapter 5**

**Abstract**

described.

**1. Introduction**

Pseudophakic Dysphotopsia

**Keywords:** pseudophakic dysphotopsia, negative dysphotopsia,

positive dysphotopsia, dysphotopsia, half-moon crescent

worldwide prevention and treatment of blindness.

**2. Pseudophakic dysphotopsia**

Pseudophakic dysphotopsia is an unwanted entoptic phenomenon caused by intraocular lenses. Dysphotopsias have been classified as positive (brightness, streaks, haze, or glare) and negative (temporal arc or half-moon crescent) in the visual field. These visual phenomena seem to be well tolerated cause in the case of positive dysphotopsia, but not as well in the negative cases that sometimes discomfort to the patient. The incidence of dysphotopsia ranges from 20% to 77.7%, and the prevalence seems not to be altered by the type of intraocular lens. Pseudophakic dysphotopsia continues to be enigmatic over time; however, many efforts are being made in order to resolve the mystery. In this chapter, the evolution of the dysphotopsia, possible causes, and proposed treatments will be

Cataract surgery has been one of the great ophthalmological contributions to the

The first cataract surgery was performed by an Indian surgeon, Sushruta, in the fifth century BC. [1–3]. Over time, improvements in cataract surgery led to many advances, such as the replacement of the opaque crystalline lens with an intraocular lens (IOL). The first IOL implant was performed by Sir Harold Ridley on November 29, 1949, at St. Thomas Hospital, London [4, 5]. Thanks to the contributions of many scientists and surgeons, techniques improved as well as IOL design. However, with the use of new technologies, complications or unwanted side effects may also

arise. Dysphotopsia secondary to IOL [6, 7], is the reason for this chapter.

Dysphotopsias are visual phenomena caused by light in phakic and pseudophakic patients. The term was introduced by Tester et al. [6] in the year 2000, and included all entoptic phenomena triggered by light (glare, halos, and dark arc). These phenomena frequently bother the patient, producing a certain degree of dissatisfaction, even in circumstances where there is good visual acuity (20/20 or

Dysphotopsia in phakic patients may improve with correction of the refractive error [8], special lenses [9], sunglasses [10], lenses with filters [11] and other techniques. In patients with significant cataracts, surgery is the option [6].

*Emely Zoraida Karam Aguilar*
