Hyperopia

Hyperopia (long sightedness) is a refractive error in which parallel light rays focus behind the retina in the relaxed eye, because the eye is too short or the optical power is too weak. Young people compensate by accommodating, which can mask the error (latent hyperopia) until accommodation weakens in the 40s. Most infants and young children are mildly hyperopic (about plus 2.00 dioptres at age 5), and this normally decreases with growth (emmetropisation).

• Causes: short axial length (commonest), flat cornea, weak lens, aphakia, pseudophakia, retinal tumours or orbital masses pushing the retina forward, central serous retinopathy, nanophthalmos (very short eye).
• Associations: accommodative esotropia in children, amblyopia (especially with anisometropia), premature presbyopia, angle closure glaucoma in high hyperopia, early cataract and reduced reading performance.
• Prevalence about 5 to 10 percent of children (higher in infants) and 25 percent of adults over 40.

• Children: usually no complaint; inward turning eye, tilted head, eye rubbing, reading difficulty, avoidance of near work, headaches, school difficulties.
• Adults: eye strain, headaches, blur at near that gets worse in the evening or with fatigue, difficulty with fine print, blur at distance in high hyperopia or older age, burning and tired eyes, watering.
• Examination: reduced near acuity and sometimes distance acuity in higher errors; esotropia with near focus; hypermetropic crowded optic disc appearance (pseudopapilloedema); shallow anterior chamber in high hyperopia.
• Red flags: esotropia, amblyopia or anisometropia in a child, leukocoria, severe pain with haloes (angle closure), sudden blur or distortion (central serous retinopathy), headaches with vomiting, high hyperopia with narrow angles, pseudopapilloedema needing differentiation from true disc swelling.

• Visual acuity, cover test, cycloplegic refraction (cyclopentolate 1 percent, 1 drop in each eye, twice, 5 minutes apart in children; atropine 1 percent twice daily for 3 days in young children with esotropia) because accommodation hides the true error.
• Fundus examination, optic disc assessment, dilated examination to exclude retinal disease.
• Gonioscopy and anterior chamber depth measurement (angle closure risk in high hyperopia), axial length and keratometry.
• Orthoptic assessment for strabismus and amblyopia.
• Differentials: presbyopia, accommodative insufficiency, convergence insufficiency, nanophthalmos, retinal detachment (late), uveal effusion.

• Children: observe low hyperopia without symptoms or squint; prescribe plus lenses for symptomatic children, esotropia, amblyopia risk, or significant error. Typical thresholds for correction without strabismus are plus 5.00 to 6.00 dioptres or more in infants, plus 3.50 to 4.50 dioptres in toddlers, and plus 2.50 to 3.00 dioptres in school age children. With accommodative esotropia, prescribe the full cycloplegic correction and review every 3 to 6 months.
• Amblyopia: patching of the better eye for 2 hours daily (moderate) to 6 hours daily (severe), or atropine 1 percent in the better eye on 2 days per week or daily, for months.
• Adults: spectacles or contact lenses worn constantly for high errors or for near tasks only for low errors; progressive or bifocal lenses with presbyopia.
• Refractive surgery: LASIK or PRK for up to about plus 4.00 dioptres; implantable lenses or refractive lens exchange for higher errors or with presbyopia.
• Angle closure risk: gonioscopy and laser peripheral iridotomy when narrow angles with risk features.
• Review every 6 to 12 months in children and every 2 years in adults; refer to ophthalmology or orthoptics for strabismus, amblyopia, high error or red flags.