Preventive Ophthalmology Melissa A. Dator & Jay Grace U. Hernandez ASMPH 2013

Blindness and Visual Impairment: Global Facts  284 million people are visually impaired worldwide – 39 million are blind  80% of visual impairment can be prevented, treated or cured!

Blindness in the Philippines  one hundred children lose their sight every week  Almost half of these cases are either treatable or preventable.  Poor nutrition, measles, and premature birth are among the leading causes of preventable blindness in children.  Early detection and treatment are the keys to saving the sight of these children.

 Individuals at risk should be easily identified  Population screening should be easy to perform, accurate and reliable  Preventive measures should be effective and acceptable to the target population  Needs cooperation among all members of society

Prevention of OCULAR injuries

Occupational Injuries  Usually from grinding or drilling jobs – propels small fragments of metal that lodge on the cornea or penetrate the globe  Using tools with sharp ends  Obtain accurate history to identify possible penetrating injury  Any worker presenting with unexplained visual loss or intraocular inflammation should be assessed

Chemical Injuries  Industrial chemicals with high concentrations of alkali or acid  Severe ocular damage – bilateral with poor visual outcome  Immediate Copious Lavage for at least 5 minutes

Protective Equipment  Workers must be properly trained in the use of tools, machinery, chemicals  Safety goggles must be worn at all times  Educate

Non-Occupational Injuries

 High incidence of severe injuries in various sports  #1 cause of eye injuries in children under 16  Corneal abrasions, lid hematomas, retinal detachments, internal bleeding  Availability of toughened plastic protective glasses with refractive correction

Windshield Injuries  Seatbelt Law  Marked reduction in incidence of severe ocular and facial damage

Bottle Cork Injury

Violent Assaults  Unexploded Bombs and Land mines – major cause of corneal blindness in children in countries at war

Ultraviolet Irradiation  Can lead to acute keratitis, corneal disorders (Pterygium), Basal Cell Carcinoma and Melanoma of the eyelids  Evidence linking UV exposure to cataract

 Sunglasses = NOT protective  Exposure to UV light happens at birth  Not advisable to put sunblock on the eyes  Educate public of dangers of prolonged sun exposure

Solar Retinopathy  Self inflicted macular damage by deliberate sun gazing without an adequate filter  Produces a thermal burn on the macula of the eye  Prevented by using adequate filters when observing eclipses  Best way = watch on TV

Prevention of Acquired Ocular Infections

 Infections – major cause of preventable ocular morbidity  Major barrier to infection – epithelium of the cornea and conjunctiva  Can be damaged directly by trauma (surgical or contact lens) or secondary effects of abnormalities of the outer eye (lid abnormalities or tear deficiency)  Corneal or Conjunctival Epithelial Defect (trauma or surgery) – use prophylactic antibiotic therapy  Avoid accidental epithelial injury in compromised eyes  Comatose patients are at risk for corneal exposure – prophylactic eyelid taping

Preoperative and Perioperative Prophylaxis  Ocular environment must be assessed pre-op to identify and treat any sources of pathogenic organisms  Pre-op instillation of Povidone-Iodine into conjunctival sac has shown to be beneficial  S. epidermidis – major cause of endophtalmitis after cataract surgery; colonizes the eyelids  Sterility must be ensured in the operative field

Contact Lens Wear and Suppurative Keratitis Pseudomonas keratitis demonstrating stromal suppuration with surrounding corneal edema and anterior chamber hypopyon. Patient had a history of extended contact lenswear.  Abnormal load of pathogenic organisms and recurrent minor trauma to corneal epithelium  Incidence higher with soft lenses, extended wear  Should be advised to keep a pair of glasses available once lenses are uncomfortable

Corneal Ulcerations  Developing countries  Greatest risk factor – trauma from agricultural activities  India: fungal and bacterial ulcers that occur after corneal abrasions can be prevented using antibiotic ointment 3x/day for 3 days

Neonatal Conjuntivitis  Neisseria gonorrhea, Chlamydia, Herpes Simplex, S. aureus, Haemophilus, S. pneumoniae  Exposure occurs during passage down birth canal  Treat mothers prior to delivery  Crede’s prophylaxis – topical erythromycin

Prevention of Iatrogenic Ocular Infection

Epidemic Keratoconjunctivitis  Adenovirus – hands, tonometer, droppers that rubbed against infected eyes  Pseudomonas aeruginosa – ophthalmic solutions  Sterilize tonometer by wiping with 70% isopropyl alcohol swabs then allow to dry before use  Immerse in disinfectant at the end of each working day

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Prevention of Ocular Damage due to Congenital Infections

 Rubella and CMV – most damaging to the infant  Rubella can be prevented by vaccination Infantile Glaucoma

Toxoplasmosis  May lead to  Chorioretinitis  Cerebral or Cerebellar Calcification  Hydrocephalus  CNS Abnormalities  Prevention: eating meat that is well cooked, washing fruits and vegetables, wearing gloves when disposing cat litter

Prevention of Genetic Diseases with Ocular Involvement

 Genetic counseling  childhood diabetes  retinitis pigmentosa  consanguineous mating  Retinoblastoma  Neurofibromatosis  Amniocentesis  Down syndrome

Early Detection of Treatable Ocular Disease

Age-Related Macular Degeneration  leading cause of permanent visual loss in the elderly in industrialized countries >50 yo  Types:  atrophic ("dry") degeneration  exudative ("wet") degeneration

Dry vs. Wet

Delaying Onset of Central Visual Loss

Treatment:  Medical  Laser photocoagulation of subretinal neovascular membranes  photodynamic therapy following IV verteporfin  Surgical:  translocation of the macula  intravitreal vascular endothelial growth factor inhibitors  ranibizumab (Lucentis), bevacizumab (Avastin)  repeated intravitreal injection

Primary Open-Angle Glaucoma  major cause of preventable blindness worldwide  2M Americans, half undiagnosed  Prevalence  0.1% for aged to 3% for over age 70  Effective tx: detection on earlier stage Ophthalmic Assessment  fluorescein angiography

Open Angle Glaucoma

 Latest Asia-Pacific Glaucoma Guidelines  case detection: conducting a comprehensive ophthalmologic examination on pt >35 yo seek ophthalmic attention for any reason

Prevention of Amblyopia "Lazy Eye"  diminished visual acuity in one eye in the absence of organic eye disease  Central vision: 0-6 or 7 y/o  2 main abnormalities  Strabismus  Anisometropia

Prevention of Amblyopia

Strabismus  Esotropia or exotropia  double vision  unused eye- not developed, unless the good eye is patched  No functional connection with the visual centers of the brain.

Anisometropia  Young children are more concerned with the perception of near objects than with those at a distance  favors the nearsighted eye  monocular blindness due to failure of visual development in an unused eye  incidence of anisometropia is about %

Prevention: Early diagnosis  Test VA of all preschool children  occlusion therapy  Illiterate "E" chart / "Home Eye Test"  Pediatricians: VA test = <4yo  Photorefraction  screening for anisometropia, ametropia, astigmatism, and strabismus in preschool children

Prevention of Ocular Damage Due to Systemic Diseases

 Diabetic retinopathy  diabetics- regular fundal examination  Blood sugar control  Proper diet  Juvenile rheumatoid arthritis  Uveitis  severe loss of vision due to glaucoma, cataract, or band keratopathy has already occurred  Regular ophthalmic screening Vitamin A deficiency disease  large intramuscular doses of vitamin A followed by corrective diet

Prevention of Visual Loss due to Drugs

Prevention of Visual Loss Due to Drugs  Ophthalmic drugs:  packaged and labelled  color-labelling  Medication history  to avoid duplication and possible overdosage

 Atropine and scopolamine: dilate the pupil in iridocyclitis  may precipitate acute glaucoma in pt with narrow anterior chamber angles.  prolonged use: conjunctivitis and allergic eczema of the eyelids.  Preservatives in eye drops: allergic reactions, cicatrizing conjunctivitis (cicatricial pemphigoid)  Topical anesthetics  Avoid prescribing or avoid long-term use  severe corneal ulceration and scarring

 Corticosteroids  depress the local defense mechanisms: corneal infection  worsen herpetic keratitis  prolonged use: open-angle glaucoma, posterior subcapsular cataract  unwise use of topical corticosteroids: severity of herpes simplex virus and varicella-zoster virus corneal infections Systemic drugs:  keratopathy, retrobulbar neuritis, retinopathy, and Stevens-Johnson syndrome (erythema multiforme)  A MUST:  take a careful history of the patient's use of drugs as part of the initial examination.