Effects of Cyclopentolate on Form Deprivation Myopia in Guinea Pigs

Purpose: To investigate the effects of intravitreal injection of cyclopentolate on form deprivation myopia in guinea pigs. Methods: Thirty-five guinea pigs at age of 3 weeks were randomly divided into 5 groups (n = 7 for each group): deprived, deprived plus saline, deprived plus cyclopentolate, normal control, and cyclopentolate group. Form deprivation was only performed in right eyes with translucent membranes for 4 weeks. Physiological saline and cyclopentolate were intravitreally injected into deprived eyes at four-day intervals. All the left eyes remained untreated as group control. Refraction was measured by retinoscopy after cycloplegia. The axial dimensions were measured by A-scan ultrasound. Subsequently, retinal histology was observed by light microscopy. Results: After 4 weeks of treatment, intravitreal injection of cyclopentolate significantly reduced the degree of myopia in the deprived eyes (from -3.92 D to -0.86 D, P < 0.001), and retarded the increase of vitreous chamber depth (from 3.83 ± 0.06 mm to 3.70 ± 0.05 mm, P < 0.001) and axial length (from 8.42 ± 0.04 mm to 8.30 ± 0.05 mm, P < 0.001) in the deprived eyes. Histological ex-amination revealed no evidence of retinal damage of eyes injected with physiological saline or cy-clopentolate compared with normal control eyes. Conclusions: Intravitreal administration of cy-clopentolate reduces axial elongation of the deprived eyes in guinea pigs. Further investigations are required to identify the optimal dose.

Comparison of non-cycloplegic photorefraction,cycloplegic photorefraction and cycloplegic retinoscopy in children

AIM: To compare the results of noncycloplegic photorefraction, cycloplegic photorefraction and cycloplegic refraction in preschool and non-verbal children.METHODS: One hundred and ninety-six eyes of 98children(50 females, 48 males) were included in the study. Firstly, non-cycloplegic photorefraction was achieved with Plusoptix A09; secondly, cycloplegic photorefraction was carried out with Plusoptix A09 after10 min cyclopentolate. Finally, 30 min after instillation of twice cyclopentolate, cycloplegic refraction was obtained with autorefraction and/or standard retinoscopy. Spheric equivalent, spheric power, cylindric power and cylindrical axis measurements were statistically compared.RESULTS: The mean age was 28.8±18.5mo(range12-72mo). The differences in spherical equivalent, spheric power and cylindrical power measured by the three methods were found statistically significant(P 【0.05).The spherical equivalent and spheric power measured by cycloplegic photorefraction were statistically higher than the measurements of the other methods(P 【0.05). The cylindrical power measured by cycloplegic refraction was statistically lower than the measurements of the photorefraction methods(P 【0.05). There was no significant difference in cylindrical axis measurements between three methods(P 】0.05).CONCLUSION: For the determination of refractive errors in children, the Plusoptix A09 measurements give incorrect results after instillation of cyclopentolate.Additionally, the cylindrical power measured by Plusoptix A09 with or without cycloplegia is higher. However, the non-cycloplegic Plusoptix A09 measures spheric equivalent and spheric power similar to cycloplegic refraction measurements in preschool and non-verbal children.

Lag of accommodation predicts clinically significant change of spherical equivalents after cycloplegia

AIM: To evaluate related factors with the change of spherical equivalents(ΔSE) and determine the suitable predictor of clinically significant ΔSE(≥0.50 D) with cyclopentolate hydrochloride on Chinese children. METHODS: A total of 145 right eyes of 145 children aged 4 to 15 y were enrolled. Intraocular pressure, axial length and lag of accommodation(LOA) were assessed before cycloplegia induced by 3 drops of 1% cyclopentolate at 5-minute intervals. SE was measured before and 1 h after the first drop of cyclopentolate. ΔSE was compared between different gender groups and among refractive groups. Multivariate linear regression analysis was performed to find related factors with ΔSE. ROC analysis was used to figure out the suitable predictor of clinically significant ΔSE.RESULTS: For the total 145 eyes, the mean SE reached up to-0.70±1.86 D from-1.30±1.62 D, with the mean ΔSE of 0.60±0.55 D. The mean ΔSE were 0.63±0.55 D and 0.57±0.56 D respectively in the male and female group(P=0.40). The mean ΔSE was significantly different among different refractive groups(P<0.0001), with the ΔSE of hyperopia group(1.12±0.64 D) larger than that of the emmetropia(0.56±0.43 D, P=0.001) and myopia group(0.32±0.28 D, P<0.0001). The ΔSE was correlated with LOA(B=-0.54, P<0.0001), cycloplegic SE(B=0.10, P<0.0001) and age(B=-0.04, P=0.015). ROC curve indicated that LOA predicted clinically significant ΔSE by 82% [area under the curve(AUC)=0.82] alone, while the value was slightly improved to 85%(AUC=0.85) in combination with axial length and 86%(AUC=0.86) in association with axial length as well as age.CONCLUSION: After cycloplegia with cyclopentolate, the ΔSE decreases with larger LOA, longer axial length and older age. Specifically, LOA plays a more vital role in predicting clinically significant ΔSE.

The Causes of Distress in Paediatric Outpatients Receiving Dilating Drops

Background/aims: Paediatric outpatients are often dilated with cyclopentolate drops. These cause discomfort and distress, which may impede subsequent examination. We aimed to determine the distress caused by cyclopentolate drops, and other factors in the clinic environment. Methods: Over an 8 week period, questionnaires were issued to guardians of all paediatric outpatients aged under 10 years receiving cyclopentolate. The childrens’distress was graded on a scale of 1 - 10 (1 = no distress, 10 = severe distress). Waiting time and ease of examination were recorded. Data was analysed using Stata statistics, and significant differences were reported at the P < 0.05 level. Results: The 72 children were grouped as under 4 years (n = 43, Group A), aged 4 - 7 years (n = 19, Group B), and aged 7-10 years (n = 10, Group C). Median distress levels at home (baseline), on arrival, on dilation, and on examination were as follows: Group A;1, 2, 7, 6 respectively;Group B;1, 1, 6, 2 and Group C;1, 1, 4.5, 1. All age groups were significantly more distressed on examination compared to baseline. Distress scores on examination were significantly greater for Group A, in keeping with the greatest number of suboptimal examinations. Guardians reported that a prolonged waiting time and bright examination lights also contributed to distress. Conclusions: This study confirms that cyclopentolate causes significant distress in young children, and in 45% of very young children, the examination is difficult. Proxymetacaine prior to cyclopentolate is a possible solution, but other distressing factors should also be addressed for optimal outcomes.