Preventive Ophthalmology

Melissa A. Dator & Jay Grace U. HernandezASMPH 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

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

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

HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHINGHAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHINGHAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHINGHAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHINGHAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHING HAND WASHINGHAND WASHING HAND WASHING HAND WASHING HAND WASHING

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

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 40-49 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 0.75-1%

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

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.