Characterizing Refractive Errors, Near Accommodative and Vergence Anomalies and Symptoms in an Optometry Clinic

Refractive, accommodative and vergence parameters and associated anomalies cause symptoms of asthenopia. Patients consult eye care practitioners mainly due to symptoms they experience. To enhance targeted treatments from various anomalies, it is relevant to study symptoms with associating anomalies.

To determine the frequencies of refractive error, accommodative and vergence anomalies, and their associations with symptoms in sample of Black South Africans.

This prospective, cross-sectional study comprised consecutive participants aged 10-40 years who attended the author's optometry practice in a Black population in South Africa. Visual acuity, refraction, accommodative and vergence tests were performed. Anomalies were classified as either single measure or syndromes based on the number of failed clinical signs.

Participants (n = 254) had mean age 22.6 ± 7.22 years. Ninety-four were male (37%) and 160 were female (63%). The frequencies of syndrome anomalies were accommodative insufficiency 17 [(6.6%) 95% CI 3.9-10.5%)], accommodative infacility 32 [(12.6%)] 8.7-17.3%] and convergence insufficiency 22 [(8.6%, 5.1-12.3%)]. Frequencies of coexisting anomalies were refractive error and accommodative 150 (60.0%), refractive error and vergence anomalies 136 (54.4%) and vergence and accommodative disorders 155 (62.0%). Most patients were symptomatic (70.9%). Headache was the most frequent symptom (41.1%).

Accommodative anomalies were more frequent than refractive error and vergence anomalies. The high frequency of anomalies suggests a high uptake of optometric services for asthenopia. Accommodative anomalies were the most symptomatic. The study highlights the need for diagnosing visual symptoms and coexisting anomalies. Establishment of validated study protocols for all accommodative and vergence anomalies is recommended.