Comparison of Spot Vision Screener and Tabletop Autorefractometer with Retinoscopy in the Pediatric Population

Objectives

Determining the accuracy of cycloplegic refractive error measurements made with the Spot Vision Screener (SVS, Welch Allyn Inc, Skaneateles Falls, NY, USA) is important for refractive assessment of uncooperative patients during optometric examinations. This study compared cycloplegic refractive errors measured by SVS and tabletop autorefractometer to cycloplegic retinoscopy in children.

Materials and Methods

Eighty-eight eyes of 44 subjects were examined in the study. Refractive error measurements were obtained under cycloplegia using retinoscopy, SVS, and Nidek ARK-530 tabletop autorefractometer (ARK-530, Nidek, Japan). Spherical and cylindrical values, spherical equivalents (SE), and Jackson cross-cylinder values at axes of 0° (J0) and 45° (J45) were recorded. Correlations between methods were analyzed using intraclass correlation coefficient (ICC) and Bland-Altman analysis.

Results

The mean age was 7 years (range: 6 months-17 years). Sixteen (36%) of the subjects were female and 28 (64%) were male. For SE there was excellent agreement between retinoscopy and SVS (ICC: 0.924) and between retinoscopy and tabletop autorefractometer (ICC: 0.995). While there was a moderate correlation between retinoscopy and SVS for cylindrical values (ICC: 0.686), excellent correlation was detected between retinoscopy and autorefractometer (ICC: 0.966). J0 and J45 crosscylinder power values were not correlated between retinoscopy and SVS (ICC: 0.472) or retinoscopy and tabletop autorefractometer (ICC: 0.442). Retinoscopy was correlated with both SVS and tabletop autorefractometer for all parameters within ±1.96 standard deviations in Bland-Altman analysis.

Conclusion

Cycloplegic retinoscopy is the gold standard for refractive error measurement in the pediatric population. However, it requires time and experienced professionals. This study revealed moderate to good agreement between SVS and retinoscopy, with better agreement in spherical errors than cylindrical errors. Although the SVS is intended for screening programs, it may also be useful in the pediatric eye office to estimate spherical refractive error in uncooperative patients.

Refractive error of canine cataract patients following implantation with three types of intraocular lenses

OBJECTIVE

To evaluate refractive state outcomes following phacoemulsification and implantation of 3 different intraocular lenses (IOLs).

ANIMALS

A prospective, randomized, controlled study was conducted on 43 client-owned dogs undergoing phacoemulsification with IOL implantation.

METHODS

Eyes were randomized to receive either an-vision Fo-X (n = 26), an-vision MD8 (18), or I-MED I-LENS (24) IOL. Refraction was measured 1 week, 1 month, and 3 months postoperatively using streak retinoscopy by 2 examiners masked to each other's results.

RESULTS

Postoperative refractive outcomes were highly correlated and not significantly different between 2 examiners for all time points (r = 0.97, 0.98, and 1.00; P = .76, .94, and .98, respectively). One week postoperatively, the refractive errors (mean ± SD) for Fo-X, MD8, and I-LENS were -0.14 ± 2.02 diopters (D), 0.97 ± 2.01 D, and 0.15 ± 2.55 D, respectively. One month postoperatively, the refractive errors were 0.35 ± 2.04 D, 0.06 ± 2.41 D, and -0.82 ± 2.20 D, respectively. Three months postoperatively, the refractive errors were -0.16 ± 2.67 D, 1.60 ± 2.99 D, and 0.59 ± 1.51 D, respectively. There were no significant differences in refractive error outcomes between Fo-X, MD8, and I-LENS at 1 week, 1 month, and 3 months postoperatively (P = .16; F(df=2,66)- = 1.89). However, the Fo-X was the only IOL to yield nearly emmetropic outcomes (±0.50 D) at all 3 time points.

CLINICAL RELEVANCE

The postoperative refractive states of dogs were not statistically different when comparing 3 types of IOLs at 3 postoperative time points, though the Fo-X was the only IOL to yield nearly emmetropic outcomes at all 3 time points.

A retinoscopic survey of donkeys and goats

PURPOSE

Assess the refractive states of donkeys and goats.

METHODS

Forty-two donkeys and 28 goats were enrolled. The mean ± SD ages were 7.68 ± 7.33 years for donkeys and 4.26 ± 2.33 years for goats. Seven donkeys and one goat were <6 months old. Retinoscopy was performed in alert animals, following cycloplegia in goats but not in donkeys. Normality was determined using the Kolmogorov-Smirnov test. The two primary meridians and two eyes were compared using Pearson's correlation and paired Student's t-tests. The association between refractive states and age was examined using one-way ANOVA in donkeys and a paired Student's t-test in goats. One-sample t-tests were conducted to assess if the refractive error distributions were significantly different from "0".

RESULTS

The mean ± SD spherical equivalent (SE) refractive errors of the right and left donkey eyes were -0.80 ± 1.03 D and -0.35 ± 0.95 D, respectively. The majority (86%) of the donkeys had an astigmatic refraction and eight (19%) had anisometropia. The mean SE refractive errors of the right and left goat eyes were -0.15 ± 1.1 D and -0.18 ± 1.2 D, respectively. The majority (54%) of the goat eyes had an astigmatic refraction and five (18%) had anisometropia. The right and left eye SE refractive errors were positively correlated in both species (both p = .9). Age was not correlated with refractive error in both donkeys (p = .09) and goats (p = .6).

CONCLUSIONS

Both goats and donkeys are emmetropic.

EEG changes as an indication of central nervous system involvement following cyclopentolate 1% eye drops; a randomized placebo-controlled pilot study in a pediatric population

To compare EEG-patterns after instillation of cyclopentolate versus placebo eye drops. Prospective, randomized, placebo-controlled, and observational pilot study is presented. Ophthalmology outpatient clinic Dutch metropolitan hospital. Healthy 6- to 15-year-old volunteers with normal or low BMI requiring a cycloplegic refraction/retinoscopy. Randomized; 1 visit 2 drops cyclopentolate-1% and 1 visit 2 drops placebo (saline-0.9%). Single-blind: conducting researcher. Double blind: subjects, parents, clinical-neurophysiology staff, neurologist, and statistician. A 10-min baseline EEG-recording, drop-application, and follow-up to at least 45 min. Primary outcome: Detection of CNS changes, i.e. EEG-pattern changes, following two drops of cyclopentolate-1%. Secondary outcome: Determination of the extent of these pattern changes. Thirty-six cyclopentolate-1% saline-0.9% EEG registrations were made in 33 subjects;  18 males and 15 females. Three subjects were tested twice (interval 7 months). Nine out of fourteen (64%) of the 11- to 15-year-old children reported impaired memory, attention, alertness, as well as mind wandering following cyclopentolate. Drowsiness and sleep were seen in EEG-recordings of 11 subjects (33%) following cyclopentolate. We observed no drowsiness nor sleep during placebo recordings. The mean time to drowsiness was 23 min. Nine subjects arrived in stage-3 sleep but none arrived in REM-sleep. In subjects without sleep (N=24), significant changes compared to placebo-EEG were present for many leads and parameters. The main findings during awake eye-open recording were as follows: 1) a significant increase of temporal Beta-1,2 and 3-power, and 2) a significant decrease in: a) the parietal and occipital Alpha-2-power, b) the frontal Delta-1-power, c) the frontal total power, and d) the occipital and parietal activation synchrony index. The former finding reflects cyclopentolate uptake in the CNS, and the latter findings provide evidence for CNS suppression. Cyclopentolate-1% eye drops can affect the CNS and may cause altered consciousness, drowsiness, and sleep with concomitant EEG results in both young children and children in puberty. There is evidence that cyclopentolate has the potency to act as a short acting CNS depressant. Nevertheless, however, cyclopentolate-1% can safely be used in children and young adolescents.

20/20: Where are Orthoptists Going?

The year 2020 has been greatly anticipated by the entire ophthalmic community. This year's Scobee lecture will be a photographic look at our past with the orthoptists and pediatric ophthalmologists we have learned from, taught, and worked with. A sobering snapshot of our present will reveal a world with extreme medical access inequality. This creates a need for an inexpensive screening device for amblyogenic anisometropia. A technique for such a fast and inexpensive screening device will be shown using first retinoscopy; and then compare the effectiveness of the direct Heine streak ophthalmoscope, a common ophthalmic instrument, will be shown to be effective in screening for ≥1 diopter of spherical anisometropia. The challenges of the present hint at an optimistic future for orthoptists, expanding their role as physician extenders to help ease the medical access inequalities in the world. Finally, I introduce the patron saint of the blind and those with vision impairment.

The Gimbalscope - A novel smartphone-assisted retinoscopy technique

The authors describe a novel technique of performing retinoscopy assisted with a smartphone (gimbalscope). We found this technique of digital retinoscopy to be useful for demonstrating and documenting retinoscopic reflexes and in addition as an easy teaching tool. This technical report explains the assembly of our smartphone-assisted retinoscope and provides examples of the range of normal and abnormal reflexes that can be captured.

Learning retinoscopy: A journey through problem space

PURPOSE

Retinoscopy is a skill that requires the integration of procedural skill and declarative knowledge. Whilst the actual technique is simple, retinoscopy is a complex skill to acquire and is one that students often find challenging. This study compared the strategies that novices, third-year students and experts use when performing retinoscopy, with the aim of identifying the key stages of learning that may enlighten teaching practice.

METHOD

This study employed a protocol-based approach in which the verbal protocols and cognitive strategies of novices, students and experts were recorded and then subjected to 'problem space' analysis.

RESULTS

Clear differences existed when the retinoscopy of novices, students and experts was directly compared using a standardised simulated task. Experts were more accurate in performance and used defined strategies to reach the goal. The presence of these strategies significantly predicted the accuracy of the retinoscopy result.

CONCLUSION

This study highlights the importance of meta-cognitive strategies and the need for an adequate theoretical foundation in skill acquisition. The underpinning knowledge provides a pedagogic tool that specifies activities which are beneficial to learning a clinical skill.

Refractive changes during off-the-axis retinoscopy in myopia

Purpose:

To analyze the refractive shift during off-the-axis retinoscopy under cycloplegic drugs in myopic patients during ocular examination.

Methods:

Prospective cross-sectional study was carried out among 10 myopic patients having refractive errors of −3.00 D or less. All the subjects underwent cycloplegic refraction by a single examiner at 0°, 10°, and 20°. Descriptive data were analyzed as mean and standard deviation. Paired t-test was used to compare the mean differences between on-axis (0°) and off-axis (10° and 20°) retinoscopy.

Result:

The mean spherical equivalent refraction of 10 myopic patients showed an increase in myopic shift with approximately 7% and 18% for 10° and 20° of eccentricity, respectively. Similarly, the mean spherical equivalent measure on axis (0°) and off axis (10° and 20°) were -2.5495, −2.737, and −3.0265, respectively. The mean spherical equivalent differences between on-axis (0°) and off-axis (10° and 20°) showed statistically significant differences with P < 0.05.

Conclusion:

This study concluded that a greater degree of eccentricity will induce a greater amount of errors in retinoscopy.

Comparison of the results of four different refraction measurement devices in children with retinoscopy

Purpose: The purpose of this study was to compare the results of 4 different autorefractometer devices with the results of retinoscopy in children. Methods: A total of 120 eyes of 60 patients aged between 6 and 18, who applied to Afyonkarahisar Health Sciences University unit of Pediatric Ophthalmology, were included in the study. Refraction with Plusoptix A09 (photoscreener) without cycloplegia was the first to be measured. Spherical and cylindrical values were recorded. Then, half an hour after the patients were instilled 2 drops of cyclopentolate with an interval of 5 minutes, dilated retinoscopy was performed, and spherical and cylindrical values were recorded. Autorefractometer measurements with cycloplegia were performed with Canon RK-F1 autorefractometer, Nidek Tonoref III and Retinomax K-Plus 3, and spherical and cylindrical values were recorded. Results: The mean age of the patients was 11.02 ± 2.1. The mean spherical equivalents were Canon RKF1 autorefractometer +0.045 ± 2.49, Nidek TonoRef III +0.023 ± 2.48, Retinomax K-Plus 3 +0.078 ± 1.42, Plusoptix A09 -0.119 ± 2.20, retinoscopy +0.124 ± 2.65. Moreover, the mean cylindrical values were Canon RK-F1 autorefractometer -0.893 ± 0.69, Nidek TonoRef III -0.927 ± 0.72, Retinomax K-Plus 3 -0.888 ± 0.73, Plusoptix A09 -0.883 ± 0.719, retinoscopy -0.923 ± 0.71. The statistical values compared with retinoscopy; Canon RKF1 spherical equivalent (p=0.376), cylindrical (p=0.515), Nidek TonoRef III spherical equivalent (p=0.485), cylindrical (p=0.198), Retinomax K-Plus 3 spherical equivalent (p=0.141), cylindrical (p=0.058), Plusoptix A09 spherical equivalent (p=0.085) and cylindrical (p=0.086) values were not different. Conclusions: In spherical and cylindrical refractive error detection, all 4 devices showed reasonable and consistent results compared to retinoscopy.

Why are we not doing retinoscopy in the school eye screening? Is distant visual acuity a sensitive tool for making referrals?

PURPOSE

School eye screening program is an integrated part of SarvaShikshyaAbhiyan. Distance visual acuity was the only tool used in such school eye screening for making referrals. We aim to evaluate the referral rate when only distance visual acuity was used as the screening tool versus using retinoscopy.

METHODS

School children were earlier screened using distant visual acuity as the sole criteria. They were again examined as per the guidelines recommended by State of Alaska and American Academy of Pediatrics, and the results of the two examinations were compared. Microsoft Excel 2007 was used for the statistical analysis.

RESULTS

Earlier 384 school children of class first to fourth (aged 6-10 years) had been screened using distant visual acuity. Of them, 87 (22.6%) were referred. The rest 297 (male 183 61.6%) students with a mean age of 7.8 years (standard deviation ± 1.23) were again examined and 42/384 (11%) were detected as having visual anomaly that were false negative/or missed during the initial screening. Refractive errors were detected in 33/42 (78.6%) students by retinoscopy. Retinoscopy showed the highest sensitivity (78.6%) and negative predictive value (96.6%) to detect all types of refractive error among all types of tests. Of 42 pair of eyes, 36 right eyes and 39 left eyes had refractive errors, mostly astigmatic, or hyperopic, which were missed earlier.

CONCLUSION

Only distance visual acuity failed to detect hyperopia and astigmatism properly. Introduction of retinoscopy would increase the validity of school eye screening.

A Novel Use of Retinoscopy for the Evaluation of Binocular Balance of Spherical Refractive Errors

PURPOSE

Binocular balancing is an important component of refractive correction to avoid asthenopic complaints. Polaroid filters are commonly used for binocular balancing; they rely on subjective examination and cannot represent daily visual activities. We describe a new examination approach to evaluate binocular balance with retinoscopy, which is an objective examination method and does not require strict patient cooperation.

METHODS

Healthy young individuals with refractive errors (under the age of 40) were included in this study. Each patient was examined by three different ophthalmologists in the same room at 20-min intervals. The first ophthalmologist performed refractive examination separately for each eye, the second physician used binocular balance tests with polaroid glasses, and the third physician practiced binocular balance test with retinoscopy. After completion of clinical examinations, autorefractometry was repeated with cycloplegia. The difference between the spherical equivalents (SE) of the eyes was calculated for each method and compared with the SE difference obtained by cycloplegic autorefractometry. The SPSS 21.0 software was used for the statistical tests.

RESULTS

The study included 30 patients (16 males, 14 females) and the mean age of the patients was 21 ± 8.5 years (range 10-37 years). There was no significant difference between the four groups for the interocular difference of SE (Greenhouse-Geisser F = 1.390, p = 0.257). The highest correlation was found between the retinoscopic binocular balance technique and cycloplegic autorefractometry (r = 0.878, p < 0.001). In addition, the intraclass correlation coefficient and the 95% limits of agreement supported strong agreement.

CONCLUSION

Currently used binocular examination tests are subjective and some patients give inconsistent answers impairing the reliability of the outcome. These tests cannot be performed on patients with limited ability to cooperate. This study demonstrates that the use of retinoscopy in the evaluation of binocular balance delivers reliable results and is a low-cost, practical approach to address the above-mentioned problems.

Agreement Between Retinoscopy, Autorefractometry and Subjective Refraction for Determining Refractive Errors in Congolese Children

OBJECTIVE

To assess the agreement between retinoscopy and autorefractometry and between subjective refraction and both retinoscopy and autorefractometry in Congolese children.

PATIENTS AND METHODS

Fifty-four children (6-17 years old) were enrolled consecutively in this cross-sectional study. Refraction was evaluated before and after cycloplegia (1% cyclopentolate) with retinoscopy and autorefractometry. Readings were compared (paired t-test) and agreement assessed with Bland-Altman plots. Subjective refraction was compared with the two methods to determine which one provides better reference estimates for subjective refraction.

RESULTS

Under cycloplegia, the spherical power was comparable between retinoscopy and autorefractometry (1.12 ± 1.37 D vs 1.22 ± 1.06D, P = 0.70), cylinder power was significantly more myopic on retinoscopy than autorefractometry (0.80 ± 1.10D vs -0.62 ± 0.66, P = 0.019), and SE was greater on autorefractometry than retinoscopy (0.91 ± 1.10D vs 0.72 ± 1.00D, P = 0.014). Retinoscopy and autorefractometry overestimated the power of spherical (P = 0.022 and 0.002, respectively) and cylindrical components (all P < 0.001). There was an agreement between retinoscopy and autorefractometry in measuring spherical (bias: 0.09 ± 0.16D; limit of agreement, LoA: -0.40 to 0.22D) and cylindrical power (bias: -0.18 ± 0.20D; LoA: -0.57 to 0.21D). Subjective refraction agreed with cycloplegic retinoscopy for determining SE power (bias: 0.11D; LoA: -0.51 to 0.73D).

CONCLUSION

Retinoscopy and autorefractometry can be used interchangeably in children for determining the power of spherical and cylindrical components. Cycloplegic retinoscopy is better than autorefractometry to obtain SE reference values for subjective refraction in children.

School bus accommodation-relaxing skiascopy

Objective

Accurate estimation of hyperopia and astigmatism is challenging in delayed children. Conventional skiascopy holds rows of increasing power ± lenses vertically in front of one eye. The school bus accommodation-relaxing skiascopy (SBA-RS) design holds child-friendly, lenses +1 to +10D horizontally so that a higher power fogs the nontested eye-relaxing accommodation without cycloplegia.

Methods

Design: Evaluation of diagnostic test. Subjects: Patients undergoing comprehensive eye examination in a pediatric ophthalmology practice. Cycloplegic (cyclopentolate 1%) retinoscopy was compared to dry SBA-RS and Retinomax (Righton, Japan) during pediatric eye examinations. Outcome measures: correlations, Chi-square and receiver operating characteristic (ROC) curve.

Results

Of 470 patients with a median age 6 years, 238 were under the age of 60 months and 110 had developmental delays. For those with cycloplegic spherical equivalent hyperopia over 0.7 D, median (90% CI) value for retinoscopy was +2.63 D (+0.75, +6.88), for SBA-RS was +2.50 D (+0.50, +6.75) and less for 184 with Retinomax +1.88 D (-1.56, +6.13) but similar despite delays. Astigmatic cylinder SBA-RS +1.50 D (+0.25, +4.00) lagged retinoscopy +1.75 D (+0.75,+4.50) but Retinomax was greater +2.00 D (+0.25, +4.64). Cycloplegic refractive components such as spherical equivalent, cylinder, and J0 and J45 power vectors correlated highly and were near unity with SBA-RS and Retinomax with the latter deviating greater. SBA-RS screened for amblyopia risk factors up to 92% sensitive and 94% specific.

Conclusion

Accommodation-relaxing horizontal skiascopy very precisely estimates astigmatism power and axis and only lags cycloplegic refraction by about 0.15D in hyperopic patients fairly independent of neurodevelopmental delay. This technique can quickly estimate refraction even in delayed patients potentially reducing some need for cycloplegia.

Clinical Trials Registry

NCT03668067.

Estimation Dynamic Distance Direct Ophthalmoscopy (eDDDO): A novel, objective method for the quantitative assessment of accommodation in young children

Purpose

To describe estimation dynamic distance direct ophthalmoscopy (eDDDO) and compare it with the monocular estimation method of dynamic retinoscopy (eDR) for the assessment of accommodation in children.

Methods

In this prospective observational cohort study, an ophthalmologist performed eDDDO followed by eDR in children with normal eyes, and then under the partial effects of cyclopentolate and tropicamide to assess performance of eDDDO with eDR under the condition of pharmacologically induced accommodation failure. Only one eye of each child was recruited in the study. To study the inter-observer variation, two masked pediatric ophthalmology fellows performed eDDDO in the similar manner.

Results

For the comparison of eDDDO with eDR, 60 eyes of 60 patients were recruited. The mean age of the patients was 10.4 years. The mean accommodation on eDDDO was 3.0D, 5.1D, 9.8D, and 11.3D at 40 cm, 25 cm, 10 cm, and 8 cm, respectively and 3.0D, 5.0D, 9.5D, and 11.0D on eDR. The eDDDO overestimated accommodation by a mean 0.17D (95% CL 0-0.48D, P = 0.5). The correlation of eDDDO with eDR was excellent (Pearson r 0.98, T value 76.0). The inter-observer difference with eDDDO was not significant (mean 1D, 95% CL 0-2.6D, P = 0.9) and the correlation between two observers was excellent (Pearson r 0.9, T value 12.7). The eDDDO and eDR were also performed on 12 eyes of 6 children with a mean age of 8.5 years (range 8-12 years) under the partial effect of cyclopentolate and tropicamide, where eDDDO overestimated the accommodation by a mean 0.3D (95% CL 0- 1.2D, P = 0.7) and the correlation was excellent (Pearson r 1.0, T value 45).

Conclusion

eDDDO is a simple, reliable, quantitative, and objective technique of accommodation assessment for children. Further studies with larger sample are required to assess its performance in disorders of accommodation affecting younger children and in children with ocular comorbidities.

Cycloplegia and spectacle prescribing in children: attitudes of UK optometrists

PURPOSE

To survey a large number of UK-based optometrists, in a variety of settings, to determine current attitudes relating to the use of cycloplegia and spectacle prescribing in children aged ≤11 years.

METHODS

One thousand randomly selected members of the College of Optometrists (UK) were invited to complete an electronic questionnaire. The questionnaire was comprised of 42 questions relating to respondent demographics, practitioner use of cycloplegia and attitudes to using cycloplegia to assess childhood refractive error and prescribing spectacles for children aged ≤11 years.

RESULTS

Three hundred and eleven practitioners (31%) completed the questionnaire. Practitioners agreed that they are confident carrying out cycloplegic refraction (60%) and instilling cyclopentolate (77%); are not concerned about the time the procedure takes (69%); feel parents are receptive to its use (65%) and are not discouraged by side effects (72%). Most practitioners agreed that they would carry out a cycloplegic refraction in pre-school children (aged 2-4 years) at their first eye exam (34% vs 27%), but would not carry out a cycloplegic refraction in a child of school age (5-7 years: 25% vs 47%, 8-11 years: 12% vs 45%). More recently qualified practitioners are more likely to be proactive in using cycloplegia (Mann-Whitney, p = 0.003). Community practitioners prescribed at slightly lower levels of ametropia in non-strabismic children than those working in a hospital setting both in the present study and in comparison to previously published hospital optometry values, particularly for hyperopia at 1 year of age.

CONCLUSIONS

This is the first study to report practitioner use of cycloplegia and attitudes to using cycloplegia to assess childhood refractive error and prescribing spectacles for children in a large number of UK-based optometrists practising in a variety of settings. The majority of practitioners responded in a positive manner to the use of cycloplegia and reported patterns of use which adhere closely to available professional guidance. However, outcomes indicate practitioners may appreciate more comprehensive evidence-based resources to inform their decision-making relating to use of cycloplegia in paediatric examination.

Repeatability of ARK-30 in a pediatric population

Purpose:

To determine repeatability and agreement of the ARK-30 handheld autorefractor with retinoscopy under cycloplegic and noncycloplegic conditions in children.

Methods:

Three consecutive autorefractor measurements (with and without cycloplegia) and retinoscopy were performed and compared in 30 randomized eyes of 30 children (mean age of 6.7 ± 2.7 years with spherical equivalent [SE] refraction from ‒4.01 to +7.38 D) in a cross-section and masked study. Bland–Altman analysis of autorefractor measurements (with and without cycloplegia) and agreement with retinoscopy were calculated with conventional notation (sphere [Sph] and cylinder [Cyl]) and vector notation (SE, J₀, and J₄₅ coefficients).

Results:

ARK-30 measurements without cycloplegia were lower than under cycloplegic conditions (Sph: ‒0.52 ± 2.37 D vs + 0.86 ± 2.60 D, P < 0.01; Cyl: ‒0.83 ± 0.80 D versus ‒0.78 ± 0.77 D, P = 0.37; and SE: ‒0.94 ± 2.19 D vs + 0.47 ± 2.44 D, P < 0.01, respectively) and statistically different (P < 0.03) from retinoscopy (Shp: +0.83 ± 2.66 D; Cyl: ‒0.71 ± 0.87 D; SE: +0.51 ± 2.49 D). Without statistical differences were in J₀ and J₄₅ coefficients. Cyloplegic autorefraction measures were not found to be statistically significantly different to retinoscopy measures. ARK-30 under cycloplegia shows better repeatability with lower limits of agreement (LoA) in Sph (LoA: ‒0.66 to +0.69 D), and SE (LoA: ‒0.66 to +0.65 D) than without cycloplegia (LoA: ‒1.45 to +1.77 D, and ‒1.38 to +1.74 D, respectively).

Conclusion:

Under noncycloplegic conditions, ARK-30 autorefractor has low repeatability and a tendency toward minus over correction in children. However, repeatability and agreement with retinoscopy under cycloplegic conditions allow use of ARK-30 in children to estimate refraction but not to substitute gold standard retinoscopic refraction.

Variant myopia: A new presentation?

Purpose:

Variant myopia (VM) presents as a discrepancy of >1 diopter (D) between subjective and objective refraction, without the presence of any accommodative dysfunction. The purpose of this study is to create a clinical profile of VM.

Methods:

Fourteen eyes of 12 VM patients who had a discrepancy of >1D between retinoscopy and subjective acceptance under both cycloplegic and noncycloplegic conditions were included in the study. Fourteen eyes of 14 age- and refractive error-matched participants served as controls. Potential participants underwent a comprehensive orthoptic examination followed by retinoscopy (Ret), closed-field autorefractor (CA), subjective acceptance (SA), choroidal and retinal thickness, ocular biometry, and higher order spherical aberrations measurements.

Results:

In the VM eyes, a statistically and clinically significant difference was noted between the Ret and CA and Ret and SA under both cycloplegic and noncycloplegic conditions (multivariate repeated measures analysis of variance, P < 0.0001). A statistically significant difference was observed between the VM eyes, non-VM eyes, and controls for choroidal thickness in all the quadrants (Univariate ANOVA P < 0.05). The VM eyes had thinner choroids (197.21 ± 13.04 μ) compared to the non-VM eyes (249.25 ± 53.70 μ) and refractive error-matched controls (264.62 ± 12.53 μ). No statistically significant differences between groups in root mean square of total higher order aberrations and spherical aberration were observed.

Conclusion:

Accommodative etiology does not play a role in the refractive discrepancy seen in individuals with the variant myopic presentation. These individuals have thinner choroids in the eye with variant myopic presentation compared to the fellow eyes and controls. Hypotheses and clinical implications of variant myopia are discussed.

Overestimation of hyperopia with autorefraction compared with retinoscopy under cycloplegia in school-age children

AIM

To compare sphere and cylinder refraction values using retinoscopy and autorefraction under cycloplegic conditions in children.

METHODS

This cross-sectional study was carried out using multistage cluster sampling. The target population was children aged 6-12 years in Shahroud, a northern city in Iran. Examinations included measurements of visual acuity, subjective refraction and objective refraction. Objective refraction was measured with and without cycloplegia with a retinoscope and an autorefractometer.

RESULTS

After applying the exclusion criteria, data from 5053 children were analysed. Spherical refraction results with autorefraction were significantly higher than results with retinoscopy (P<0.001). Refraction overestimation was significant in all age groups (P<0.0001). Comparison of differences in different spherical ametropia subgroups also showed a significant intermethod difference in all refractive states (P<0. 01). Overall, autorefraction tended to over plus hyperopics and under minus myopic cases compared with retinoscopy. The 95% limits of agreement for spherical values measured with the two techniques were -0.35 Diopter (D) to 0.50 D. The values of J₀ and J₄₅ vectors with autorefraction were significantly higher than those with retinoscopy (P<0.001). The 95% limits of agreement between the two methods for vectors J₀ and J₄₅ were -0.12 D to 0.15 D and -0.10 D to 0.11 D, respectively.

CONCLUSION

Since the observed differences in spherical refraction and the cylindrical components obtained through retinoscopy and autorefraction are statistically significant, but clinically insignificant, and the two methods have a strong correlation and agreement, it can be concluded that autorefraction can be a suitable substitute for retinoscopy in children under cycloplegic conditions.

Intra- and inter- examiner repeatability of cycloplegic retinoscopy among young children

PURPOSE

To evaluate the intra- and inter-examiner repeatability of cycloplegic retinoscopy in young children aged 4-5 years old.

METHODS

Examiner 1 refracted all children in the first sample (n = 108); firstly with masked loose lenses, then using unmasked loose lenses (intra-examiner repeatability). Examiners 1 and 2 refracted all children in the second sample (n = 97) using unmasked loose lenses, blind to the child's refractive error, presence/magnitude of habitual spectacle correction and to each other's findings (inter-examiner repeatability). Refractions were performed on one eye chosen at random. Mean differences, 95% limits of agreement (LOAs) and confidence intervals were calculated for intra- and inter-examiner repeatability of sphere, cylinder and spherical equivalent refraction (SER).

RESULTS

Participants had a wide range of refractive errors (-1.50DS to +7.25DS; ≥4.50DC). Mean differences (95% LOAs) were small for both intra- and inter-examiner repeatability [Intra: Sphere 0.00D (-0.85, +0.85D), Cylinder -0.03D (-0.68, +0.62D), SER -0.06D (-0.90, +0.78D); Inter: Sphere -0.08D (-0.92, +0.76D), Cylinder -0.08D (-0.75, +0.59D), SER -0.13D (-0.95, +0.69D). A statistically significant proportional bias was present for intra-examiner repeatability of cylinder (ρ = 0.20, p = 0.04) and SER measurement (ρ = 0.19, p = 0.049). Proportional bias was not present for any other measure (p > 0.12). Examiners agreed on cylinder axis within ±20^° in 71% of refractions where astigmatism of -0.75D or higher was present. 80% of intra- and inter-examiner measures fell within ±0.50D for spherical and cylindrical components.

CONCLUSIONS

Differences of ±1.00D and ±0.75D or more for spherical and cylindrical measures respectively can be considered significant when performing cycloplegic retinoscopy on young children.

Calculation of posterior chamber intraocular lens (IOL) size and dioptric power for use in pet rabbits undergoing phacoemulsification

OBJECTIVES

To calculate the size and dioptric power of a posterior chamber intraocular lens (IOL) to achieve emmetropia in adult rabbits and to compare the dioptric power calculation results using a proprietary predictive formula to a retinoscopy-based method.

ANIMALS STUDIED

Three wild rabbit cadavers, seven pet rabbits with cataracts and ten healthy pet rabbits.

MATERIALS AND METHODS

Implant size was calculated using a capsular tension ring (CTR) (Acrivet^® , Berlin, Germany). Published and cadaveric biometric data were used in the predictive formula. An IOL power-escalation study compared the predicted values to the refraction results of one pet rabbit (P1) fitted with a + 41D canine IOL (Acrivet^® ) and six pet rabbits (P2-P7) fitted with prototype IOLs (Acrivet^® ). Retinoscopy of 10 healthy pet rabbits served as controls.

RESULTS

A 13.5 mm CTR fitted in all rabbits and permitted the use of a 13 mm IOL. The predicted IOL power ranged between +24D and +25D. The +41D IOL resulted in a refraction error of +8D. Progressive recalculation through a calibration formula led to the insertion of three +49D IOLs in two pet rabbits and a refraction of +6D to +8D, followed by seven +58D IOLs in four pet rabbits and a refraction median of 0D (range: -1.5D to +1D).

CONCLUSIONS

A 13 mm prototype IOL of +58D achieves emmetropia and is of adequate size for rabbits. The combined use of a CTR and retinoscopy is a useful method to calculate the size and refractive power of a new, species-specific, veterinary IOL.

A Comparison of Refraction Defects in Childhood Measured Using Plusoptix S09, 2WIN Photorefractometer, Benchtop Autorefractometer, and Cycloplegic Retinoscopy

PURPOSE

To compare Plusoptix (Gmbh, Nuremberg, Germany), 2WIN (Adaptica, Padua, Italy), the benchtop refractometer (Auto-Kerato-Refractometer KR-8900; Topcon Co, Tokyo, Japan), and retinoscopy with regard to the consistencies.

MATERIALS AND METHODS

In our prospective study, 200 eyes of 100 patients were included. We analyzed the demographics and characteristics of the patients, the percentage of patients from whom measurements could not be obtained, the measurements from both patients' eyes of pupil diameter, spherical, cylindrical, axis, and spherical equivalence.

RESULTS

The mean age ± SD was 7.8±4.5 years (range, 1-18 years). Pupil diameter measurements were found to be consistent (Cronbach's alpha value >0.8). The sphere and spherical equivalence measurements for both eyes were found to be consistent with each other in all apparatus (Cronbach's alpha value >0.8). However, consistency was found to be lower in cylindrical values and the Jackson cross-cylinder measurements at 0° and 45° axis were found to be inconsistent with each other (Cronbach's alpha value <0.8).

CONCLUSIONS

While consistency was observed in all methods in terms of sphere and spherical equivalence, consistency dropped in cylindrical values and no consistency was observed in axis values. It is important to take this point into consideration, especially in axis measurements.

Clinical Competency of 1-Year Trained Vision Technicians in Andhra Pradesh, India

PURPOSE

To assess clinical competency of 1-year trained vision technicians (VTs) in detecting and referring causes of visual impairment in India.

METHODS

Eye examination results and management plans for 328 patients examined by 24 VTs in 24 vision centers of LV Prasad Eye Institute in Andhra Pradesh were compared with those of a standard optometrist who examined the same patients. Eye examinations included retinoscopy and subjective refraction, slit lamp examination, applanation tonometry and undilated direct ophthalmoscopy. Data were analyzed for level of concordance in retinoscopy, spectacle prescription, disease detection and referral.

RESULTS

VTs demonstrated moderate to good levels of agreement in refraction, disease detection and referral. Sensitivity and specificity for ocular pathology identification were 77.4% (95% confidence interval, CI, 69.4-84.2%) and 86.6% (95% CI 81.1-91.1%), respectively. The highest sensitivity was demonstrated in detecting significant cataract (91.5%) and refractive error (83.0%). VT spectacle prescriptions were accurate 76% of the time for mean spherical equivalent and 65% of the time for astigmatism. VT sensitivity in detecting posterior segment abnormalities was low (18.5%) resulting in failure to detect retinal conditions such as diabetic retinopathy and maculopathy. Despite lack of recognition of the specific pathology, referral decisions were correct in 78.4% of cases.

CONCLUSION

VTs in India competently detect and manage or refer the two most common causes of visual impairment; uncorrected refractive error and cataract. Over two-thirds of patients received accurate and appropriate services from VTs, suggesting that they are a useful and competent cadre for rural and remote eye care.

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 98 children (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 after 10 min cyclopentolate. Finally, 30min 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 (range 12-72mo). 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.

Comparison of the Retinomax hand-held autorefractor versus table-top autorefractor and retinoscopy

AIM

To compare noncycloplegic and cycloplegic results of Retinomax measurements with findings achieved after cycloplegia using table-top autorefractor and retinoscopy.

METHODS

The study included 127 patients (mean age 96.7mo, range 21 to 221). Retinomax (Rmax) (Nikon Inc., Japan) was used to obtain noncycloplegic refraction. Under cycloplegia, refraction was measured with Rmax, table-top autorefractor (TTR) (Nikon NRK 8000, Inc., Japan) and retinoscopy. The values of sphere, spherical equivalent, cylinder and axis of cylinder were recorded for Rmax, TTR and retinoscopy in each eye. All results were analyzed statistically.

RESULTS

THE MEAN SPHERIC VALUES (SV), SPHERICAL EQUIVALENT VALUES (SEV) AND CYLINDRICAL VALUES (CV) OF THE NONCYCLOPLEGIC RMAX (SV: 0.64 D, SEV: 0.65 D and CV: 0.03 D, respectively) were found to be significantly lower than cycloplegic TTR (1.43 D, 1.38 D and 0.3 D; P=0.012, P=0.011 and P=0.04, respectively) and retinoscopy (1.34 D, 1.45 D and 0.23 D; P=0.04, P=0.002 and P=0.045, respectively). Mean cycloplegic SV, SEV, CV were not significantly different between Rmax and TTR, Rmax and retinoscopy, TTR and retinoscopy. Cycloplegic or noncycloplegic axis values were not different between any method.

CONCLUSION

Rmax may be used successfully as a screening tool but may not be accurate enough for actual spectacle prescription. Cycloplegic Rmax measurements may be able to identify refractive error in children because of approximate results to retinoscopy.

Non-cycloplegic spherical equivalent refraction in adults: comparison of the double-pass system, retinoscopy, subjective refraction and a table-mounted autorefractor

AIM

To evaluate the accuracy of spherical equivalent (SE) estimates of a double-pass system and to compare it with retinoscopy, subjective refraction and a table-mounted autorefractor.

METHODS

Non-cycloplegic refraction was performed on 125 eyes of 65 healthy adults (age 23.5±3.0 years) from October 2010 to January 2011 using retinoscopy, subjective refraction, autorefraction (Auto kerato-refractometer TOPCON KR-8100, Japan) and a double-pass system (Optical Quality Analysis System, OQAS, Visiometrics S.L., Spain). Nine consecutive measurements with the double-pass system were performed on a subgroup of 22 eyes to assess repeatability. To evaluate the trueness of the OQAS instrument, the SE laboratory bias between the double-pass system and the other techniques was calculated.

RESULTS

The SE mean coefficient of repeatability obtained was 0.22D. Significant correlations could be established between the OQAS and the SE obtained with retinoscopy (r=0.956, P<0.001), subjective refraction (r=0.955, P<0.001) and autorefraction (r=0.957, P<0.001). The differences in SE between the double-pass system and the other techniques were significant (P<0.001), but lacked clinical relevance except for retinoscopy; Retinoscopy gave more hyperopic values than the double-pass system -0.51±0.50D as well as the subjective refraction -0.23±0.50D; More myopic values were achieved by means of autorefraction 0.24±0.49D.

CONCLUSION

The double-pass system provides accurate and reliable estimates of the SE that can be used for clinical studies. This technique can determine the correct focus position to assess the ocular optical quality. However, it has a relatively small measuring range in comparison with autorefractors (-8.00 to +5.00D), and requires prior information on the refractive state of the patient.

A psychophysical technique for estimating the accuracy and precision of retinoscopy

BACKGROUND

The accuracy and precision of retinoscopy need to be evaluated in an objective and unambiguous manner to judge an individual's performance in this task during training or in research for consistent measurements of refractive error. This study describes and evaluates a psychophysical technique for obtaining simultaneous and unbiased estimates of accuracy and precision in retinoscopy.

METHODS

Subjects with zero to 12 years of experience with retinoscopy performed the psychophysical task on a model eye (75 subjects) and on a cyclopleged human eye with spherical refractive error (30 subjects). Subjects made forced choice judgments of 'with' or 'against' for lens powers within ± 0.5 D of expected neutrality (in 0.12 D steps), each placed 20 times before the eye in random order. Accuracy and precision were determined from the mean and standard deviation of the resultant psychometric function.

RESULTS

Subjects could be qualitatively divided into those with good and poor accuracy and precision based on the task outcomes. The median and inter-quartile range of accuracy (no experience: 0.16 ± 0.34 D; four or more years of experience: 0.06 ± 0.11 D) and precision (no experience: 0.30 ± 0.39 D; four or more years of experience group: 0.13 ± 0.08 D) improved with task experience (p < 0.001). Median accuracy and precision in the human eye were similar to the model eye (p > 0.8). Accuracy and precision were poorly correlated with each other for both the human eye and model eye (|ρ| ≤ 0.20; p ≥ 0.09 for all).

CONCLUSION

The psychophysical retinoscopic task could differentiate subjects based on their accuracy and precision and also capture key elements of improvement in retinoscopic performance with experience. Retinoscopic performance using this task was similar to previous reports using routine clinical retinoscopy. Therefore, the psychophysical technique may be used to evaluate and monitor objectively retinoscopic performance.

Clinical comparison of the Welch Allyn SureSight™ handheld autorefractor vs. streak retinoscopy in dogs

OBJECTIVE

To compare the Welch Allyn SureSight™ wavefront autorefractor with retinoscopy in normal dogs.

ANIMALS STUDIED

Fifty privately owned dogs (100 eyes) of 20 breeds, free of ocular disease. Mean ± SD age: 5.7 ± 3.25 years (range: 6 months-13 years).

PROCEDURES

The refractive error was determined in each eye by two experienced retinoscopists using streak retinoscopy as well as by an autorefractor operated by two different examiners. Measurements were performed before and approximately 30-45 min after cycloplegia was induced by cyclopentolate 0.5% and tropicamide 0.5% ophthalmic solutions.

RESULTS

Mean ± SD noncyclopleged retinoscopy net sphere was -0.55 ± 1.14 (range: -3.75 to 3.5) diopters (D). Mean cyclopleged retinoscopy net sphere was -0.52 ± 1.18 (range: -4.25 to 2) D. Mean ± SD noncyclopleged autorefractor spherical equivalent (SE) was -0.42 ± 1.13 D (range: -3.36 to 2.73) D. Mean cyclopleged autorefractor SE was 0.10 ± 1.47 (range: -5.62 to 3.19) D. Noncyclopleged autorefraction results were not significantly different from streak retinoscopy (whether noncyclopleged or cyclopleged, P = 0.80 and P = 0.26, respectively). Cyclopleged autorefraction results were significantly different from noncyclopleged or cyclopleged streak retinoscopy (P < 0.0001 in both states). There was no significant difference between noncyclopleged and cyclopleged streak retinoscopy (P = 0.97).

CONCLUSIONS

Noncyclopleged autorefraction shows good agreement with streak retinoscopy in dogs and may be a useful clinical technique. Cycloplegia does not significantly affect streak retinoscopy results in dogs.

A comparison of the Plusoptix S08 photorefractor to retinoscopy and cycloretinoscopy

BACKGROUND

The aim was to compare outcome measures of refractive error by the Plusoptix S08 photorefractor with measures obtained by retinoscopy and cycloretinoscopy in children.

METHOD

The refractive error of the right eye of 144 non-strabismic children, aged 2.5 to 5.5 years, was determined by Plusoptix S08 photorefraction, retinoscopy and cycloretinoscopy. Agreement between outcome measures of refractive error (spherical error, cylindrical error and spherical equivalent) by the three techniques were tested by Bland-Altman limits of agreement.

RESULTS

The mean difference for spherical equivalent results of photorefraction (P(se)) minus those of retinoscopy (R(se)) and photorefraction minus those of cycloretinoscopy (CR(se)) were +0.53 ± 0.62 D and -0.22 ± 0.75 D, respectively. The 95 per cent limits of agreement for spherical photorefraction with retinoscopy and cycloretinoscopy were ±1.22 D (range -0.69 to +1.75) and ±1.47 D (range -1.69 to +1.25), respectively. The mean difference for cylindrical results of photorefraction (P(c)) minus those of retinoscopy (R(c)) and Pc minus those of cycloretinoscopy (CR(c)) were +0.11 ± 0.39 D and +0.13 ± 0.44 D, respectively. The 95 per cent limits of agreement for P(c) with R(c) and CR(c) were ±0.76 D (range -0.65 to +0.87) and ±0.86 D (range -0.73 to +0.99), respectively. The mean and standard deviation of weighted axes difference, comparing Plusoptix S08 and retinoscopy was 0.25 ± 0.36 and comparing Plusoptix S08 and cycloretinoscopy was 0.29 ± 0.51. Eighty-two per cent of the spherical equivalent findings in photorefraction and cycloretinoscopy show a difference of within 1.00 D. Regarding cylindrical power, this percentage is 96.6 per cent.

CONCLUSION

As the findings demonstrate a fairly good consistency between the results of the Plusoptix S08 Photorefractor without using cycloplegic agents and those of cycloretinoscopy, the Plusoptix S08 is a fairly accurate tool to estimate refractive errors of children in the limited working range of the instrument.

A comparison of manifest refractions, cycloplegic refractions and retinoscopy on the RMA-3000 autorefractometer in children aged 3 to 15 years

PURPOSE

The study was conducted to compare the accuracy of readings of the RMA-3000 autorefractometer (Topcon, Tokyo, Japan) with traditional retinoscopy as a means of determining the approximate subjective refraction in children after cycloplegia.

METHODS

142 children aged 3 to 15 years were included. All children had their refractive status measured with the RMA-3000 autorefractometer (noncycloplegic autorefraction [AR]). Subsequently all children underwent cycloplegia and the refractive status was estimated again with the autorefractometer (cycloplegic autorefraction [ARC]) and traditional retinoscopy (RC) by examiners who were unaware of the results from the other techniques.

RESULTS

From 69 right eyes with negative sphere we observed that the sphere power was significantly higher (more than 0.5 diopters) in AR than in ARC (P = 0.0001) and RC (P = 0.0001). From the 73 normal and hyperopic right eyes we observed that the sphere power was significantly lower (more than 0.5 diopters) in AR than in ARC (P = 0.0001) and RC (P = 0.0001).

CONCLUSIONS

The use of the autorefractometer in children (in whom accommodation is more active than older patients) without cycloplegia may underestimate the actual hyperopia and overestimate the actual myopia. Manual retinoscopy is still the most accurate technique to estimate refractive status in children.