Inclusion Criteria:
* Parent/guardian provision of signed and dated informed consent form for Baseline/Eligibility Examination.
* Completion of Baseline/Eligibility Examination with cycloplegia.
* Bilateral astigmatism: Astigmatism ≥2.25D in the most astigmatic eye and ≥1.75D in the fellow eye based on manual cycloplegic retinoscopy conducted at Baseline/Eligibility Examination.
* Parent/guardian willing to accept assignment to either randomized group.
* Parent/guardian provision of signed and dated informed consent form for randomized SPEC Study.
* Parent willing to commit to study visits every 180 days, to be contacted (phone, email, or text) for reports of spectacle wear, and to allow their child to wear the TheraMon® sensor on the spectacle headband.
* Child and Family are primarily English or Spanish speaking.
* Parent/guardian does not anticipate moving out of Tucson area prior to their child reaching age 1275 days (approximately age 3 ½ years).
* Parent/guardian has not enrolled another child in the SPEC trial.
Exclusion Criteria:
* Gestational age \<32 weeks (per parent report).
* Anisometropia ≥1.50 D spherical equivalent per manual cycloplegic retinoscopy conducted at the Baseline/Eligibility Examination.
* Current manifest strabismus per Baseline/Eligibility Examination.
* Ocular pathology per Baseline/Eligibility Examination (H44\* or H25\* diagnosis code).
* Previously diagnosed manifest strabismus or other ocular abnormalities (per parent report and per medical record):
* H25\* (Cataract)
* H44\* (Disorders of the Globe)
* H50\* (Strabismus)
* H55\* (Irregular Eye Movement and Nystagmus)
* Q15.0 (Congenital Glaucoma)
* Other diagnosis of an ocular abnormality
* Previous spectacle wear, amblyopia therapy, or vision therapy (per parent report and per medical record).
* H53\* (Amblyopia)
* Other spectacle wear, amblyopia therapy, or vision therapy
* Current or previous diagnosis of developmental or neurological conditions (per parent report and per medical record):
* H90.5 Congenital Deafness, and related disorders of hearing loss.
* G40.909 Epilepsy or other seizure disorder.
* P07.34 Prematurity 31 weeks, and other prematurity less than 32 weeks.
* P91.6 Hypoxic Ischemic Encephalopathy
* Q90.9 Down Syndrome, and other congenital syndromes associated with developmental delay.
* Q04.4 Septo-Optic Dysplasia
* Q91-Q92 Trisomy Other (13, 18, partial, complete, unbalanced translocations, mosaicism, duplications)
* R62.50 Developmental Delay, and related disorders exhibiting a delay in one or more streams of development (e.g. language, fine motor, gross motor, social).
* Other diagnosis of a developmental or neurological condition
* History of allergic response to dilating eye drops (per parent report):
* Local redness and swelling of the eyelid consistent with contact dermatitis which resulted in the parent being informed that the child had a drug allergy to one of the dilating eye drops (proparacaine or cyclopentolate) or one of the carrier or preservative agents used in the formulation of these drops.
