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Comparisons of Using Cycloplegic Biometry Versus Non-cycloplegic Biometry in the Calculation of the Cycloplegic
Zhirong Wang1, Rui Xie1, Ruiyu Luo1
1State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, 54 Xianlie S Rd, Guangzhou, 510060, China.
Insights
Cycloplegic biometry may overestimate lens power (LP) in children with low to moderate myopia. This finding is crucial for understanding refractive development and improving eye care research in pediatric populations.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Biometry
Background:
- Accurate crystalline lens power (LP) calculation is vital for understanding refractive development in children.
- Previous studies have not fully explored the impact of cycloplegia on LP calculations using biometry data.
- This study investigates the differences in LP calculations between non-cycloplegic and cycloplegic measurements in a pediatric cohort.
Purpose of the Study:
- To compare lens power (LP) calculated using non-cycloplegic and cycloplegic biometry data in children.
- To identify factors associated with differences in LP calculations.
- To inform research on refractive development in pediatric populations.
Main Methods:
- Biometric data (corneal radii, corneal power, anterior chamber depth, lens thickness, axial length) were collected from 821 children using IOLMaster 700 before and after cycloplegia.
- Lens power (LP) was calculated using Bennett's formula, with cycloplegic (cLP) and non-cycloplegic (nLP) values determined.
- Differences in LP (ΔLP) were analyzed concerning age, gender, and refractive state, with associated factors explored via correlation and regression analyses.
Main Results:
- Cycloplegia significantly affected anterior chamber depth, lens thickness, and anterior segment length (p < 0.001).
- No significant differences were found in axial length, corneal power, or AL/CR ratio post-cycloplegia.
- A significant difference was observed between nLP and cLP (p = 0.001), with a mean ΔLP of 0.11 ± 0.87 D. |ΔLP| was associated with ΔASL (p < 0.001).
Conclusions:
- Cycloplegic biometry may lead to an overestimation of lens power (LP) in children with low and moderate myopia.
- The findings highlight the importance of considering cycloplegia status in pediatric refractive error assessments.
- This research contributes to a better understanding of refractive development and may aid in future pediatric eye care research.
Introduction:
This study investigated the difference between the calculation of cycloplegic crystalline lens power (LP) using non-cycloplegic and cycloplegic biometry data in children, and associated factors were explored.
Methods:
A total of 821 children were enrolled and only right eye was analyzed. The corneal radii (CR), corneal power (CP), anterior chamber depth (ACD), lens thickness (LT), and axial length (AL) before and after cycloplegia were obtained using IOLMaster 700. Anterior segment length (ASL) was defined as ACD plus LT. The cycloplegic LP was calculated with Bennett's formula. In addition, LP calculated with cycloplegic data was defined as cLP, otherwise it was defined as nLP. The ΔLP (defined as the value as cLP minus nLP) was compared among age, gender, and refractive states groups. Associated factors of ΔLP and |ΔLP| were explored by Pearson's correlation and multivariate linear regression.
Results:
The mean age of the 821 subjects was 9.83 ± 2.97 years with a mean spherical equivalent refraction (SER) of - 1.06 ± 2.12 D. Overall, the ACD, LT, and ASL were significantly affected by cycloplegia agent (all p < 0.001; paired t test). Conversely, no statistically significant differences were documented in AL, CP, or AL/CR ratio before and after inducing cycloplegia (p = 0.917, p = 0.515, and p = 0.549, respectively). Significant difference was found between nLP and cLP (21.24 ± 1.58 D vs 21.43 ± 1.92 D, p = 0.001). The mean ΔLP was 0.11 ± 0.87 D (range from - 7.01 D to 7.08 D). Significant change in LP was found in low and medium groups, respectively (0.13 ± 0.81 D, p = 0.001; 0.11 ± 0.48 D, p = 0.043). In the multiple regression analysis, |ΔLP| was exclusively associated with ΔASL (β = 0.172, [95% CI 0.112-0.300], p < 0.001).
Conclusion:
Our results indicated that using cycloplegic biometry could lead to an overestimation in LP for low and moderate myopia eyes. This finding is likely to facilitate the refractive development research in children.
Trial Registration:
ClinicalTrials.gov identifier, NCT05247099.
