MYOPIA

RALPH P. GARZIA

STAGES - MYOPIA DEVELOPMENT

+Low hyperopia - less in the evening

+Emmetropia

Hyperopia at times

+Daily recurrent transient myopia, often times after near tasks or later in the day or when fatigued

+Transitional myopia

Variable amount of myopia

Fluctuations in magnitude

+Fixed magnitude of myopia

Indications of progression

+Stabilized myopia

PSEUDOMYOPIA -

WEIRD REFRACTIVE STUFF INDICATIVE OF PSEUDOMYOPIA

I.

Retinoscopy -1.25 20/20

Subjective -0.50 20/15

NOTE: a.) -0.75 D less minus for 1 line of VA; b.) with control of accommodation during a refraction, amount of myopia is reduced.

II.

Unaided VA OD, OS 20/30

OU 20/20

NOTE: acuity improvement under binocular conditions; accommodation more stable

III.

Unaided VA 20/30-

Subjective plano, 20/20

NOTE: subjective refraction stabilizes accommodation to an emmetropia status

IV.

Unaided VA 20/25

Subjective -1.00 20/20

NOTE: differential between amount of blur and the amount of minus for maximum VA

V.

Dry refraction vs. Wet refraction

NOTE: classic pseudomyopia profile of elimination or reduction of myopia under cycloplegic conditions

SUMMARY OF WIERD REFRACTIVE STUFF

1. Lack of correlation between VA, retinoscopy & subjective

2. Inconsistent effect of blurring lenses

3. Variable, noisy refraction

OPTOMETRIC RISK FACTORS (for myopia development or progression)

1. Weird refractive stuff as noted above

2. Refraction in infancy (age 1 year)

NOTE: 1.) children with + spherical equivalent, stay hyperopic; 2.) children with - spherical equivalent & x90 or no cylinder are more likely to be myopic during school age thanb x180.

3. Refraction when entering school

NOTE: a.) if child is myopic at age 5-6 years, the myopia will remain and probably increase; 2.) if spherical refraction Ò+1.50, very likely to remain hyperopic; 3.) if between +0.50 & +1.25, likely to be emmetropic; 4.) if between 0.00 & +0.50, a high probability of becoming myopic (80%). The probability is even greater if x90 astigmatism is present

4. Age at incidence

NOTE: i.e. earlier the onset, more likely a higher terminal amount of myopia

5. accommodative / convergence function are related to myopia progression

a. low PRA

b. esophoria at near point

c. high near point cross cylinder

NOTE: these looks like convergence excess / accommodative insufficiency

6. Presence of accommodative astigmatism

NOTE: evidence of increased levels of lenticular astigmatism

SYSTEMIC RISK FACTORS (for myopia development or progression)

1. Heredity

2. Socio-economic status

3. Ethnicity

4. Educational level

NOTE: higher educational level attained is related to higher prevalence and amounts of myopia (10 fold increase in myopia prevalence between the most and least educated, 18-54 years); e.g. optometry students, military academies, etc.

5. Early academic achievement

NOTE: children who become myopic are already better achievers in the early school years than those children who do not become myopic

6. Intelligence (IQ scores)

NOTE: there is a relationship between IQ and prevalence of myopia

7. Occupation

8. Nutrition, illness

MANAGEMENT

SCHOOL AGED CHILDREN

1. Full correction

NOTE: emmetropization is effected by image quality (i.e. blur). Therefore, you would want to fully correct refraction

2. Under correction

NOTE: traditional method of myopic control. Myopes are more susceptible to over minus refractions. Also, an undercorrection will reduce accommodative demands

3. Near point add

NOTE: bifocal corrections appear to be effective in cases of myopia progression associated with convergence excess / accommodative insufficiency

4. Orthoptics

NOTE: directed at remediation of the underlying convergence excess / accommodative insufficiency

5. Contact lenses

NOTE: hard or soft?

6. Hygiene

NOTE: good lighting, taking breaks, etc.

7. Over correction

8. BI prism

9. Nutrition

10. Biofeedback