Contact Lenses

• Introduction• Prevalence• History• Types• Indication• Contra-indication• Complication• Acanthamoeba Keratitis.

.Topics

Contact Lens is a thin lens placed directly on the surface of the eye. Contact lenses are considered medical devices and can be worn to correct vision, or for cosmetic or therapeutic reasons.

.Introduction

• Around 125 million people use contact lenses worldwide.

• Contact lens market was estimated at $6.1 billion

• Average age of contact lens wearers globally was 31 years old and two thirds of wearers were female.

• Egypt??

.Some Statistics

• Medical Use • In Sports and other outdoor activities (instead of glasses)• Cosmoteic use (non-medical)

.Common Uses

Famous Italian architect, mathematician and inventor Leonardo da Vinci produced the first known sketches (in 1508) that suggested the optics of the human eye could be altered by placing the cornea directly in contact with water.

.History

.HistoryF.A. Muller created the first known glass contact lens in 1887. Other reports say Swiss physician Adolf E. Fick and Paris optician Edouard Kalt created and fitted the first glass contact lenses to correct vision problems in 1888.

.HistoryIn 1936, New York optometrist William Feinbloom (1904-1985) introduced scleral lenses made of a combination of glass and plastic that were significantly lighter than older glass-blown contacts.

.HistoryIn 1948, California optician Kevin Tuohy (1919-1968) introduced the first contact lenses that resembled modern gas permeable (GP) contact lenses of today.

.HistoryPerhaps the biggest event in the history of contact lenses was the invention of the first hydrophilic hydrogel soft contact lens material by Czech chemists Otto Wichterle and Drahoslav Lim in 1959. that led to the 1971 launch of the first FDA-approved soft contact lenses in the United States — Bausch + Lomb's "SofLens" brand contacts.

• Rigid gas-permeable • Daily-wear soft lenses• Extended-wear• Extended-wear disposable• Planned replacement:

.Types

Optical Indications

• Most wearers use lenses to correct errors of refraction instead of using glasses.

• majority are myopic with or without astigmatism.

Medical Indications• Keratoconus• Unilateral Aphakia• Irregular Astigmatism and/or Corneal Opacification• Nystagmus• After Penetrating Keratoplasty• or refractive surgery

.Indication

 First it is important to evaluate the patient’s motivation, ocular needs, and ocular and medical history.  

Primary ocular contraindications to the use of contact lenses:

1. Any acute or subacute inflammation 2. Acute and chronic ocular infections3. Any eye disease affecting the cornea, conjunctiva, and lids (e.g.,

epithelial fragility, endothelial failure, dry eye, allergy, pinguecula, pterygium)

4. Corneal hypesthesia5. Uncontrolled glaucoma6. Vitreocorneal touch in aphakia7. Psychological intolerance to the foreign body

.Contra-indication

.Complicationsit is important to evaluate the patient’s motivation, ocular needs, and ocular and medical history.

• Corneal edema ( ttt: higher oxygen prem)• Corneal distortion (test for astigmatism)• Sterile infiltrates (ttt: topical steroid drops)• Neovascularization (removing stimuli)• Keratitis : Hypoxic - toxic - suppurative • Microbial Keratitis: i.e Pseudomonas

• Acanthamoeba is a genus of amoebae, one of the most common protozoa in soil, and frequently found in fresh water and other habitats.

• When present in the eye, Acanthamoeba strains can cause acanthamoebic keratitis, which may lead to corneal ulcers or even blindness.

• This condition occurs most often among contact lens wearers who do not properly disinfect their lenses, exacerbated by a failure to wash hands prior to handling the lenses.

• AK treatment is usually difficult• Neomycin, ketoconazole, diamdines• Keratoplasty may sometimes be required.

Acanthamoeba Keratitis

Prevalenceo A recently published study was conducted by an institution in Austria. The

goal was to diagnose Acanthamoeba keratitis to give an overview of proven cases of Acanthamoeba infections in Austria during the past 20 years indicated that:

o 89% of the infected patients were contact lens wearers, o where,60% of the infected patients were females.

In Egypt:

• 2014: 49.2% of samples collected from 10 different examined swimming-pool water at Cairo

• 2015: 33.3% and 16.7% of inlet and outlet samples at Damanhour Drinking Water Treatment Plant (DWTP) before and after conventional drinking wate treatment

Acanthamoeba Keratitis

Wash your hands properly

Rub the surface of the contact lens before storing.

Use only sterile products

Contact lens solution must be discarded upon opening the case, and fresh solution used instead.

.Precautions DO DO not

• Saline solution and rewetting drops donot disinfect CL

• Avoid using tap water to wash or store contact lenses.

• Do not sleep in contact lenses unless prescribed.

• Never after swimming.

• Never swap lenses with others

• Never put in your mouth.

• See your optometrist regularly for evaluation

Google Smart Contact Lens

.A scene from the future

• Our review indicated no recent reports for prevalence of contact lenses usage in Egypt.

• We also indicated no reports for acanthamoeba keratitis prevalence in Egypt, so there is an apparent need for reports of current state of the disease among contact lenses weares as there are reports of high prevalence of Acanthamoeba in Fresh water.

.Home Message

Thank You

Done By:Hatem Refaat El-Sheemy

Eman M. Roshdey Yara Gamal

Mohamed Salah Anas El Raei

Under Supervision ofProf.Dr. Hala El-Mofty

15-12-2015