Effect of progressive addition lenses on myopia progression in Japanese children: a prospective, randomized, double-masked, crossover trial.

PURPOSE: This prospective, randomized, double-masked, crossover trial was conducted to evaluate the clinical effectiveness of progressive addition lenses (PALs) compared with single-vision lenses (SVLs) on myopia progression in Japanese children. METHODS: Ninety-two children fulfilling the inclusion criteria (age: 6-12 years, spherical equivalent refractive errors: -1.25 to -6.00 D) were randomly allocated to either 18 months of wearing PALs (near addition: +1.50 D) followed by 18 months of SVLs (group 1), or 18 months of wearing SVLs followed by 18 months of wearing PALs (group 2), and were followed up for 3 years (two-stage crossover design). The primary outcome measure was myopia progression, as determined by cycloplegic autorefraction. RESULTS: Eighty-six (93%) children completed both treatment periods. A mixed-model, two-way analysis of variance (ANOVA) performed using 3-year data identified a significant treatment effect of PALs compared with SVLs (P = 0.0007), with a mean 18-month difference of 0.17 D (95% CI: 0.07-0.26 D). This analysis also indicated a significant period effect (P = 0.0040) and a significant treatment-by-period interaction (P = 0.0223): Group 1 showed a slower myopia progression than did group 2. CONCLUSIONS: The use of PALs slowed myopia progression, although the treatment effect was small, as previously reported in ethnically diverse children in the United States. The significant treatment-by-period interaction suggests that early application of PALs would probably be more beneficial for these age and refraction ranges (isrctn.org number, 28611140).

Downward deviation of progressive addition lenses in a myopia control trial.

PURPOSE: To clarify how the downward deviation of progressive addition lenses (PALs) reduces their near-addition effect in schoolchildren participating in a myopia control trial. METHODS: Among 95 schoolchildren wearing PALs for 6 months (age range: 6-12 years; refractive error range: -6.00 to -1.25 D), facial images were captured with a digital still camera placed 60 cm in front of the eyes while he or she was looking ahead with natural head posture. The vertical deviations of PALs from their ideal position (mm) were evaluated by analysing these images. RESULTS: The mean (+/-SD) downward deviations of PALs for the right and left eyes were 3.7 +/- 2.3 and 3.7 +/- 2.0 mm, respectively, and the largest downward deviation was 10.2 mm. For simulations using the average downward deviation, the near-addition effect of PALs was reduced to 30 and 63% of the expected value at the 10 degrees and 20 degrees downward eye positions, respectively. CONCLUSIONS: The downward deviation of PALs is a significant factor in reducing their therapeutic effect for near-addition. To ensure the proper alignment of PALs in children, the conventional spectacle-frame-fitting procedure is not sufficient, and repeated confirmation using a testing method similar to that used in this study is required.

Accommodative lag under habitual seeing conditions: comparison between myopic and emmetropic children.

PURPOSE: To determine whether or not myopic children have a larger lag of accommodation than emmetropic children under natural seeing conditions. METHODS: In 61 myopic children (age, 9.5 +/- 1.3 years; spherical equivalent refractive error, -6.50 to -1.00 D), accommodative response was objectively measured while they were binocularly viewing a target at 50.5, 32.5, 20.9, or 16.0 cm (1.98-6.25 D) through fully correcting glasses. In the 33 children who habitually wore spectacles, the accommodative responses were also measured while they wore their own spectacles. As controls, 18 emmetropic children were recruited. Accommodative response gradients and lags were compared between the groups after calibration for residual refractive errors and the vertex distance of the glasses. RESULTS: With fully correcting glasses, the myopic children showed a larger mean lag of accommodation than the emmetropic children, as well as wide intersubject variation. However, when the children wore their habitual, usually undercorrecting, spectacles, accommodative lags markedly decreased, and a significant correlation was found between residual refractive errors after correcting for the spectacles and accommodative lags. Myopic children with near-point exophoria tended to show smaller lags of accommodation. CONCLUSION: Under binocular viewing conditions, myopic children when viewing the target through fully correcting glasses tend to show larger lags of accommodation than emmetropic children, but the lags of accommodation are usually reduced by their spectacle undercorrection.

Myopia control trial with progressive addition lenses in Japanese schoolchildren: baseline measures of refraction, accommodation, and heterophoria.

PURPOSE: To describe baseline measures of refraction, accommodation, and heterophoria in Japanese schoolchildren enrolled in a randomized clinical trial that examines whether progressive addition lenses slow myopic progression compared with single-focus lenses. METHODS: Ninety-five children with myopia between -1.25 and -6.00 D spherical equivalent were recruited. Their ages ranged from 6 to 12 years; 46% were girls. The main outcome measure for the trial was progression of myopia determined by cycloplegic (0.5% tropicamide) autorefraction. Accommodative lags and heterophoria were also evaluated. RESULTS: Because data were similar in both eyes, they are reported for the right eye only. The mean (+/-SD) cycloplegic autorefraction (spherical equivalent) was -3.22 +/- 1.22 D. The cycloplegic subjective refraction was larger (less myopic) than the noncycloplegic subjective refraction by 0.25 +/- 0.22 D. The mean distance prescription was larger (undercorrection) than the mean cycloplegic autorefraction by 0.74 +/- 0.37 D. The mean accommodative lag for a 4.74 D target was 2.05 +/- 0.98 D. Near-point esophoria was found in 29 (31%) of the children when their refractive errors were fully corrected with glasses. CONCLUSIONS: The measurements reported herein will serve as a basis for assessing changes that occur over a 3-year follow-up period. Compared with the baseline measurements in the Correction of Myopia Evaluation Trial, clear differences were observed in the mean cycloplegic autorefraction and distance prescriptions. The accommodation and heterophoria data showed characteristics similar to those recently reported in myopic children abroad.

Accommodative lag under habitual seeing conditions: comparison between adult myopes and emmetropes.

PURPOSE: To clarify whether myopes show poor accommodative response and thus have a larger accommodative lag under natural seeing conditions. METHODS: Forty-three adults without other ocular abnormalities were classified into the early-onset myopia (EOM, n=28) and the emmetropia (EMM, n=15) groups. The subjects wore glasses or contact lenses that they habitually used, and accommodative responses to four accommodative targets (16.0-50.5 cm from their eyes) were measured under a monocular or binocular condition using an open-field infrared autorefractometer. RESULTS: Under a binocular condition, the accommodative lag for each target was significantly smaller in the EOM group (analysis of variance, P<.01), but the mean slope of the accommodative stimulus-response function did not significantly differ between the EOM and EMM groups (1.05+/-0.11 and 1.02+/-0.10 D/D, respectively). The mean slope under a binocular condition was significantly steeper than that under a monocular condition in both groups (paired t-test, P<.05). CONCLUSIONS: In adults with EOM, the accommodative stimulus-response function was not impaired, and the habitual accommodative lag was rather small, probably due to the reduced accommodative demand by a vertex distance and/or the intentional undercorrection of spectacles.

Contribution of vergence adaptation to difference in vertical deviation between distance and near viewing in patients with superior oblique palsy.

PURPOSE: To evaluate the adaptive vertical vergence aftereffect and determine whether it contributes to a difference of vertical deviation with respect to gaze distance in patients with vertical strabismus. DESIGN: Prospective noncomparative studies. METHODS: Eighty-four patients with unilateral superior oblique palsies were enrolled and classified into three types-A, B, and C-based on the difference in vertical deviation between distant and near viewing. The prism adaptation test was performed for 2 to 3 hours to correct vertical deviation and the response of vertical deviation to the prism adaptation test was compared among the three types RESULTS: Adaptive vertical vergence aftereffect, defined as an increase of deviation by 5 prism diopters or more with the prism adaptation test, was identified in 13 patients (16%) at distance and in 23 patients (27%) at near viewing. Among the three types, the adaptive vergence aftereffect contributed mostly to the type B, in which distance deviation exceeds near deviation. Nine patients (39%) of type B changed to type A category with the prism adaptation test; and of these, 7 increased near deviation so that the deviation difference between distant and near viewing decreased. CONCLUSION: The adaptive vertical vergence aftereffect contributes to a difference in vertical deviation between distant and near viewing. The vertical prism adaptation test is specifically useful to determine the extent of surgery by breaking fusional vergence in patients with hypertropia in whom deviation differs with respect to viewing distance.

Accuracy of suture adjustment in adjustable strabismus surgery evaluated at the initial postoperative examination.

PURPOSE: To clarify the efficacy of sliding-noose type adjustable suture strabismus surgery, we evaluated the accuracy of suture adjustment based on data from the initial postoperative examination performed 1-4 weeks after the surgery. METHODS: Thirty-four patients with various types of strabismus participated [age range, 12-79 years; range of far deviation, 4-123 prism diopters (PD)]. Under sub-Tenon anesthesia, a recession (with or without a resection or muscle transposition) was performed with an adjustable suture (Guyton's procedure), and the suture was adjusted 6-24 hours after surgery. RESULTS: Twenty-six (76%) patients required suture adjustment one to eight times. In 50% and 75% of our patients, the errors from individual target angle were within +/- 0.8 and +/- 2.0 PD, respectively, whereas 2 (6%) patients with esotropia showed an undercorrection larger than 10 PD. The error distribution was almost the same throughout the range of preoperative deviation. CONCLUSION: By using an adjustable suture with a sliding noose, pinpoint alignment of the eyes can be achieved in more than half of the cases, at least in the early postoperative period.

[Accuracy of suture adjustment in sliding noose type adjustable strabismus surgery].

PURPOSE: To clarify the efficacy of adjustable suture strabismus surgery with sliding noose, we evaluated the accuracy of suture adjustment. METHODS AND SUBJECTS: Thirty-four patients with various types of strabismus participated [age range: 12-79 years, range of far deviation: 4-123 prism diopters(PD)]. Under sub-Tenon anesthesia, a recession(with or without an additional resection or a muscle transposition) was performed with an adjustable suture(Guyton's procedure), and the suture was adjusted 6-24 hours after the surgery. Based on the initial postoperative examination performed 1-4 weeks(mean: 2.8 weeks) after the surgery, errors in the far deviation from the individual target were analyzed. RESULTS: Twenty-six(76%) patients required suture adjustment 1-8 times. In 50% and 75% of our patients, the errors were within +/- 0.8 and +/- 2.0 PD, respectively, whereas 2(6%) patients with esotropia showed an undercorrection larger than 10 PD. Distribution of the errors was the same throughout the range of pre-operative deviation. CONCLUSION: By using the sliding noose type adjustable suture, a pin-point alignment of the eyes can be established in more than 50% of cases, at least, in the early post-operative period.