Changes in Ocular Parameters and Intraocular Lens Powers in Aging Cycloplegic Eyes

Changes in ocular biometrics following cycloplegic refraction in strabismic and amblyopic children

This study was aimed to analyze ocular biometric changes following cycloplegia in pediatric patients with strabismus and amblyopia. Cycloplegia is routinely used to measure refractive error accurately by paralyzing accommodation. However, effects on axial length (AL), anterior chamber depth (ACD), keratometry (Km), and white-to-white distance (WTW) are not well studied in this population. This retrospective study examined 797 patients (1566 eyes) undergoing cycloplegic refraction at a Samsung Kangbuk hospital pediatric ophthalmology clinic from 2010 to 2023. Ocular biometry was measured before and after instilling 1% cyclopentolate and 0.5% phenylephrine/0.5% tropicamide. Patients were categorized by strabismus diagnosis, age, refractive error and amblyopia status. Differences in AL, ACD, Km, WTW, and refractive error pre- and post-cycloplegia were analyzed using paired t tests. ACD (3.44 ± 0.33 vs 3.58 ± 0.29 mm, P < .05) and WTW (12.09 ± 0.42 vs 12.30 ± 0.60 mm, P < .05) increased significantly after cycloplegia in all groups except other strabismus subgroup (Cs) in both parameters and youngest subgroup (G1) in ACD. Refractive error demonstrated a hyperopic shift from -0.48 ± 3.00 D to -0.06 ± 3.32 D (P < .05) in overall and a myopic shift from -6.97 ± 4.27 to -8.10 ± 2.26 in high myopia (HM). Also, AL and Km did not change significantly. In conclusion, cycloplegia impacts ocular biometrics in children with strabismus and amblyopia, significantly increasing ACD and WTW. Refractive error shifts hyperopically in esotropia subgroup (ET) and myopically in high myopia subgroup (HM), eldest subgroup (G3) relating more to anterior segment changes than AL/Km. Understanding cycloplegic effects on biometry is important for optimizing refractive correction in these patients.

Assessing the Impact of Tropicamide on Anterior Segment Parameters in Diabetic Patients: A Randomized Clinical Trial

INTRODUCTION

Evaluation of anterior segment parameters is crucial in ophthalmic procedures such as intraocular surgeries and contact lens fitting. However, the use of tropicamide in diabetic patients presents challenges due to its potential impact on biometric measurements. This study aims to investigate and compare the effects of 0.5% and 1% tropicamide on anterior segment parameters in diabetic patients.

METHODS

This double-masked randomized clinical trial enrolled 98 patients with diabetes mellitus. Participants were randomly assigned to receive either 0.5% or 1% tropicamide. Anterior segment parameters were measured using Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany) before and 30 minutes after tropicamide administration. Parameters included anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), keratometry, central corneal thickness (CCT), white-to-white distance (WTW), and pupillary diameter (PD).

RESULTS

Both concentrations of 0.5% and 1% tropicamide induced significant changes in anterior segment parameters. There was a notable increase in PD (2.99 ± 0.62, 3.11 ± 0.55, respectively, both P-values < 0.001), ACD (both 0.10 ± 0.05, both P-values < 0.001), ACV (16.69 ± 9.56, 17.51 ± 9.26, respectively, both P-values < 0.001), and WTW (0.06 ± 0.14, 0.03 ± 0.30, respectively, both P-values < 0.001), along with a decrease in ACA (-3.50 ± 10.65, -3.30 ± 6.87, P-value < 0.001 and P-value=0.001, respectively), and CCT (-6.10 ± 8.06, -6.39 ± 9.97, respectively, both P-values < 0.001) post-dilation. However, no significant changes were observed in keratometry (front Km (-0.03 ± 0.19, -0.04 ± 0.21, respectively), back Km (0.01 ± 0.05, 0.004 ± 0.05, respectively), P-values> 0.05).

CONCLUSION

Both concentrations of tropicamide exhibited comparable effects on anterior segment parameters in diabetic patients. These post-dilation changes should be considered for accurate intraocular lens power calculation and decision-making for cataract, phakic intraocular lens, and refractive surgeries.

Changes in ocular biological parameters after cycloplegia based on dioptre, age and sex

The effects of cycloplegia on ocular biological parameters in children have been extensively studied, but few studies have compared these parameters between different refractive states, ages, and sexes. Therefore, the purpose of this study was to investigate the changes in ocular biometry before and after cycloplegia in different groups based on dioptre, age and sex. We examined a total of 2049 participants in this cross-sectional study. A comprehensive eye examination was conducted before cycloplegia. Cycloplegia was implemented with the application of atropine or tropicamide. Ocular biological parameters were evaluated after cycloplegia, including axial length (AL), mean keratometry (K), flat keratometry (K1), steep keratometry (K2), central corneal thickness (CCT), anterior chamber depth (ACD) and white-to-white (WTW) distance. All the participants were categorized based on dioptre, age and sex. Statistical analysis was performed with paired t tests and Wilcoxon signed-rank tests. Regarding dioptre, AL was found to be increased significantly in the Fs, Ast and FA (p < 0.05) postcycloplegia groups. We observed significant increases in K, K1, K2 and ACD in the Fs group (p < 0.05) after cycloplegia. Regarding age, we found significant increases in AL, CCT and ACD in group 1 (p < 0.05), but AL decreased significantly in groups 2 and 3 (p < 0.05) postcycloplegia. There were no significant changes found in K, K1 and K2 in the three groups after cycloplegia (p > 0.05). Regarding sex, AL and WTW were found to decrease significantly among males and increase significantly among females (p < 0.05) postcycloplegia, while K, K1 and K2 showed the opposite trends. This study showed that there were differences in some ocular biological parameters after cycloplegia across different groups; in particular, there were significant differences in AL, CCT and ACD. Attention should be devoted to the influence of cycloplegia in clinical work.

Effect of pupil dilation on biometry measurements and intraocular lens power in eyes with high myopia

Purpose

The present study sought to evaluate the effects of pupil dilation on ocular parameter measurements and intraocular lens (IOL) power calculation using IOLMaster in highly myopic cataract patients.

Materials and methods

A total of 233 eyes were included in this prospective study and assigned to four groups based on range of axial length (AL) as follows: group A:26–28 mm, group B:28–30 mm, group C:30–32 mm, and group D:32–36 mm. Flattest and steepest keratometry (K1 and K2), AL, anterior chamber depth (ACD), lens thickness (LT), and white-to-white (WtW) were determined using IOLMaster before and after administration of topical tropicamide. The corresponding IOL powers were calculated using Sanders–Retzlaff–Kraff/theoretical (SRK/T), Haigis, and Barrett Universal II formulas.

Results

Variations in AL, K1 and K2 following dilation were not significant (P > 0.05 in all groups). The results showed that ACD increased significantly after dilation (P = 0.000 in all groups), whereas LT decreased significantly after dilation (P = 0.000, 0.000, 0.001, and 0.003). Post-dilation WtW increased significantly in Group A, B, and C (P = 0.001, 0.001, and 0.025) but not in Group D. When IOL power was calculated as a discrete variable, significant differences were observed between pre- and post-dilation IOL power.

Conclusion

Pupil dilation in cataract eyes with high myopia does not cause significant changes in AL and K. However, it significantly increases ACD as well as WtW values and significantly decreases the LT value. Surgeons should evaluate the effect of pupil dilation on IOL power prediction as the present findings show extreme cases. Notably, Barrett Universal II formula had the best concordance between different pupil conditions in long eyes.

Effect of age and cycloplegia on the morphology of the human crystalline lens: swept-source OCT study

PURPOSE

To evaluate the effect of age and cycloplegia on the morphology of the crystalline lens using a swept-source optical coherence tomography (SS-OCT) system.

SETTING

Hospital.

DESIGN

Prospective cross-sectional study.

METHODS

The parameters including anterior chamber depth (ACD), the radii of curvature of the anterior and posterior surface of the crystalline lens (ALR and PLR), lens thickness (LT), lens equatorial diameter (LED), and lens vault (LV) were quantified by the SS-OCT before and after cycloplegia. The paired t test was used to compare the parameters before and after cycloplegia. A multivariate linear regression model was built to analyze the association between the parameters/cycloplegia-induced changes and age, while adjusting for the effect of axial length, refractive status, and sex.

RESULTS

76 individuals (age range, 18 to 86 years) were recruited. The ALR and ACD were negatively correlated with age (P ≤ .002), and the LT, LV, and LED were positively correlated with age (P ≤ .004). In participants younger than 60 years, the ALR and ACD significantly increased, whereas the LV and LT significantly decreased after cycloplegia (all P < .001). With aging, cycloplegia-induced differences of ALR (P = .001) and ACD (P = .014) significantly decreased, and of LT (P < .001), LT (P < .001), and LV (P = .001) significantly increased.

CONCLUSIONS

The crystalline lens morphology measured by the SS-OCT revealed steepening anterior surface and increasing equatorial diameter with age. Cycloplegia caused a significant change of anterior surface morphology in participants younger than 60 years, and this effect diminished with age.

Do Gender, Age, Body Mass and Height Influence Eye Biometrical Properties in Young Adults? A Pilot Study

BACKGROUND

Do gender, age, body mass and height influence eye biometrical properties in young adults?

METHODS

A total of 155 eyes (92 female, 63 male) of healthy subjects between the ages of 18 and 39 years were included in the study. The subjects' gender and age were recorded, and their body mass, height and biometrical properties of the eyes were measured.

RESULTS

The male subjects had significantly thicker and flatter corneas and lower minimal rim-to-disk ratios than the female subjects did. In both genders, age showed strong, negative correlations with anterior chamber depth and pupil diameter and a positive correlation with lens thickness. We also found significant, negative correlations between body height and mass with keratometry measurements, negative correlations between body height and optic disk rim area and rim volume, and positive correlations between body mass and axial length in both genders.

CONCLUSIONS

Biometric eye parameters differ among people. In addition to age and gender, which are usually taken into consideration when interpreting ocular biometry findings, we strongly suggest that body height and mass should be also routinely considered when interpreting eye biometry data, as these factors have an impact on ocular biometry.

Effect of eyedrops and applanation tonometry on optical biometry

PURPOSE

To determine whether eyedrops (phenylephrine, tropicamide, and fluorescein-proparacaine) and Goldmann applanation tonometry (GAT) have an effect on optical biometry measurements for preoperative cataract surgery workup.

SETTING

George Washington University, Washington, DC.

DESIGN

Nonrandomized controlled trial.

METHODS

Participants older than 18 years with no contraindications to eyedrops or tonometry were recruited. Optical biometry measurements were obtained on a single eye using the Lenstar LS900. One drop each of phenylephrine, tropicamide, and fluorescein-proparacaine was applied to the same eye, and measurements were repeated. GAT was performed, and measurements were repeated. For controls, the contralateral eye was also measured at each interval.

RESULTS

There was no statistically significant difference in mean predicted postoperative refraction (PPOR) keratometry (K) 1, K2, or axis postdrops and post-GAT 62 eyes (n = 62). After drops were applied, mean central corneal thickness increased from 540 to 542 µm (P = .0002), mean anterior chamber depth (ACD) increased from 3.68 to 3.70 mm (P < .0001), and lens thickness (LT) decreased from 3.66 to 3.65 (P = .001). After GAT, ACD increased to 3.76 mm (P < .0001), and LT increased to 3.60 mm (P < .0001). There was no statistically significant difference in PPOR or other parameters for the control eyes (n = 5).

CONCLUSIONS

GAT and phenylephrine, tropicamide, and fluorescein-proparacaine drops did not affect the primary outcome of PPOR. This suggests that cataract surgery candidates do not need to return for a separate preoperative visit for optical biometry.

Effects of Cyclopentolate Hydrochloride Dosage on Anterior Segment Parameters in Young Adults (Measured with Pentacam)

Purpose

To assess the effects of 0.5% and 1% cyclopentolate on the main parameters of the anterior segment (central corneal thickness (CCT), anterior chamber angle (ACA), depth (ACD) and volume (ACV)) in low/moderate myopia and hyperopia along with the effect on IOP.

Patients and Methods

Both eyes of 30 subjects (15 myopic and 15 hyperopic) with mean age±standard deviation of 21.4±3.6 years were enrolled. Each participant was administered two drops of cyclopentolate 1% in the right eye and two drops of cyclopentolate 0.5% in the left eye, 15 minutes apart. All participants underwent intraocular pressure (IOP) measurement using noncontact tonometry, and anterior chamber parameter measurement using Pentacam.

Results

Following the use of 0.5% and 1% cyclopentolate among the hyperopic group, there was a statistically significant increase in ACD for 1% (pre 2.762±0.28 mm and post 2.89±0.25 mm) and 0.5% (pre 2.71±0.28 and post 2.86±0.27 mm) and ACV for 1% (pre 141.40±20.59 mm³ and post 154.35±19.69 mm³) and 0.5% (pre 137.40±20.48 mm³ and post 152.93±20.50 mm³). In contrast, ACA decreased with both doses 1% and 0.5%, but was not statistically significant (p for both >0.05%). With 0.5% and 1% cyclopentolate among the myopia group, there was a significant increase in ACD following cyclopentolate 1% (pre 3.18±0.22 mm and post 3.25±0.21 mm) and 0.5% (pre 3.200±0.22 mm and post 3.26±0.05 mm), p˂0.05. The ACV was significantly increased following 1% cyclopentolate, p˂0.001. The ACA showed a statistically significant decrease following cyclopentolate 1%, P=0.01, but not a significant decrease after cyclopentolate 0.5%, P=0.170. There was a significant increase in the IOP after 1%, p˂0.001, while a decrease with 0.5%, p=0.008.

Conclusion

A topical dosage of cyclopentolate 1% showed significant changes in ACA and ACV among the hyperopia and myopic groups compared to 0.5%. Therefore, it is important to consider the use of a 0.5% cyclopentolate dosage to minimize changes to anterior chamber parameters.

Comparisons of atropine versus cyclopentolate cycloplegia in myopic children

CLINICAL RELEVANCE

In clinical practice, 1% atropine and 1% cyclopentolate are used as cycloplegia agents to diagnose refractive error. The influence of 1% atropine on ocular biometry is obscure, and the impact of 1% cyclopentolate remains controversial.

BACKGROUND

This study aims to compare the effects of atropine versus cyclopentolate cycloplegia on ocular biometry in myopic children and to determine the sites of action for atropine.

METHODS

A total of 207 myopic children aged 6-12-years were included in the analysis. All participants underwent comprehensive eye examinations before and after cyclopentolate cycloplegia, after which they were randomly assigned into two groups, A and B, in a ratio of 1:1, to receive 1% or 0.01% atropine, respectively. The treatment was administered once every night for a week. Participants were re-examined one week later.

RESULTS

Cyclopentolate cycloplegia caused a decrease in choroidal thickness (-3 ± 9 μm, p = 0.001), elongation of axial length (9 ± 16 μm, p < 0.001), loss of lens power (-0.14 ± 0.37 dioptre, p < 0.001), and a hyperopic shift (0.14 ± 0.22 dioptre, p < 0.001) in both groups. However, ocular biometry showed different changes after one-week use of 1% or 0.01% atropine (all p < 0.001). In Group A, choroid thickening (24 ± 13 μm, p < 0.001) and reduced axial length (-30 ± 27 μm, p < 0.001) were observed after atropine cycloplegia, with greater changes in lens power (0.50 ± 0.37 dioptre, p < 0.001) and spherical equivalent (0.52 ± 0.23 dioptre, p < 0.001). Group B showed a slight increase in choroidal thickness following one-week use of 0.01% atropine (6 ± 9 μm, p < 0.001), but other biometric measures showed no significant changes.

CONCLUSION

Cyclopentolate and atropine cycloplegia have different effects on ocular biometry. Both 1% cyclopentolate cycloplegia and 0.01% atropine resulted in choroidal thickening, indicating that the choroid may be a site of action for atropine.

The effect of cycloplegia on the ocular biometry and intraocular lens power based on age

BACKGROUND

To investigate the effect of cycloplegia on the ocular biometry and intraocular lens (IOL) power in different age groups.

METHODS

This cross-sectional study enrolled 240 right eyes of 240 healthy volunteers. Three groups were formed (range to years; group 1: 50-60, group 2: 30-40 and group 3: 10-20, respectively). We measured keratometry, central corneal thickness (CCT), white-to-white (WtW) distance, anterior chamber depth (ACD), and axial lentgh (AL) both before and after cycloplegia. The IOL powers were calculated using Sanders-Retzlaff-Kraff/theoretical (SRK/T), Holladay 1 and Haigis formulas. AL-Scan (Nidek Co., Gamagori, Japan) was used for all measurements.

RESULTS

There was a significant increased in keratometry, CCT, ACD, AL, and Holladay 1 after cycloplegia (p < 0.05), whereas WtW, SRK/T, and Haigis were not changed significantly in group 1 (p > 0.05). Keratometry, SRK/T, Haigis, and Holladay 1 significantly decreased; ACD and WtW significantly increased postcycloplegia (p < 0.05) but AL and CCT did not change significantly in group 2 (p > 0.05). Significant increased in ACD, CCT, WtW, and AL, significant decreased in SRK/T and Haigis were observed postcycloplegia (p < 0.05), while the changes in keratometry and Holladay 1 were not significant in group 3 (p > 0.05).

CONCLUSIONS

This study demonstrated there is significant difference in many ocular parameters and IOL power formulas before and after cycloplegia. Especially, ACD showed significant changes in all age groups. Therefore, to avoid refractive prediction errors the IOL power calculation formulas using the ACD should be considered.

The Effect of Cycloplegia on the Ocular Biometric and Anterior Segment Parameters: A Cross-Sectional Study

Introduction

To evaluate the effects of cycloplegia on the biometric components and anterior segment parameters of the eye.

Methods

In this cross-sectional study, changes to axial length (AL), anterior chamber depth (ACD) lens thickness, anterior chamber angle (ACA) and volume, corneal thickness in the pupil center (PC), corneal curvature (CC) and white-to-white (WTW) following cycloplegia induced by tropicamide 1% in 42 eyes of patients aged 23–58 years were assessed. Biometric components and anterior segment parameters were measured using an IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany) and a Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany), respectively.

Results

Significant statistical changes in ACD (increased by 0.06 ± 0.05 mm; p < 0.001), anterior chamber volume (increased by 15.19 ± 10.32 mm³; p < 0.001), ACA (decreased by 2.18 ± 10.20°; p = 0.029) and lens thickness (decreased by 0.02 ± 0.03 mm; p < 0.001) were observed post-cycloplegia, while the changes in CC, corneal thickness in the PC, WTW and AL were not statistically different (p > 0.05). Also, a significant inferior displacement of the PC along the vertical axes was seen (p = 0.020).

Conclusion

Cycloplegia resulted in a deeper ACD and thinner lens thickness. These changes should be considered in determining intraocular lens (IOL) power to prevent refractive surprises in cataract surgery and also in the phakic IOL implantation.