Persistent strabismus after cataract extraction

Cataract surgery is not associated with post-operative binocular vision anomalies in age-related cataract patients

PURPOSE

To compare the binocular vision status of patients pre- and post-cataract surgery, and to investigate the risk factors for patients who develop binocular vision anomalies post-surgery.

METHODS

A prospective study of patients (≥50 years) who elected to undergo bilateral cataract surgery was implemented. A comprehensive binocular vision test battery including stereopsis, ocular alignment, fusional vergence, vergence facility, near point of convergence and the Convergence Insufficiency Symptom Survey (CISS) was administered before the first surgery and at the third visit after surgery on the second eye. A detailed diagnostic classification protocol was applied to identify the presence of binocular vision anomalies pre- and post-surgery.

RESULTS

Seventy-three participants were included at baseline, 24 (33%) of whom were diagnosed with non-strabismic binocular vision anomalies (NSBVA), mainly convergence insufficiency (18/73, 25%). Fifty-one participants completed the post-operative evaluation, 17 (33%) of whom had NSBVA pre-surgery and 13 (26%) post-surgery (p = 0.48). There were a number of conversions from NSBVA to normal binocular vision and vice versa. Logistic regression showed that the adjusted odds ratio of pre-existing NSBVA diagnosis for predicting the risk of post-operative NSBVA was 6.37 (p < 0.01). There were no significant changes in most binocular vision measures post-surgery, except for a significant improvement in the CISS score (p < 0.01, Cohen's d = 0.83).

CONCLUSIONS

Binocular vision anomalies, especially convergence insufficiency, are prevalent in the age-related cataract population. Cataract surgery does not appear to be a significant risk factor for the development of new binocular vision anomalies. A pre-existing binocular vision anomaly is the main risk factor for predicting a post-operative binocular vision anomaly in this population.

Preoperative binocular vision characteristics in the age-related cataract population

Background

This study is the first part of the “Binocular Vision Anomalies after Cataract Surgery” study that aimed to investigate the impact of cataract surgery on binocular vision status in adults with age-related cataract. This study aimed to investigate the preoperative binocular vision status of participants with age-related cataract.

Methods

Patients who elected to undergo bilateral cataract surgery (≥50 years of age) were recruited. Clinical measures of binocular vision including stereopsis, ocular alignment, fusional vergence, vergence facility, convergence amplitude and a symptom survey related to binocular vision anomalies were administered. A detailed classification protocol was established to identify the presence of binocular vision anomalies. The frequency of specific binocular vision anomalies and normative data of binocular vision measures were reported.

Results

A total of 73 subjects were evaluated. No strabismus was detected in the cohort. Non-strabismic binocular vision anomalies were detected in 24 subjects (32.9%), of whom 18 (24.7%) had convergence insufficiency, 3 (4.1%) had basic exophoria, 2 (2.7%) had convergence excess, and 1 (1.4%) had fusional vergence dysfunction. Decreased vergence facility and convergence amplitude were more common compared to the pre-presbyopes (P < 0.01).

Conclusion

Binocular vision problems, especially convergence insufficiency, are common in the adults with age-related cataract. The study results demonstrate that the lack of normative binocular vision data for the presbyopic population is a significant gap in the literature and suggest the need for a study of normative data for this population.

Trial registration

The study was registered at ClinicalTrials.gov (NCT03592615, USA).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02418-7.