Utility of retinoscopy to examine peripheral refraction

Purpose: This study explored whether retinoscopy (RET) provides comparable results of relative peripheral refraction (RPR) to open–field autorefractometry (AR) in myopic subjects.Methods: Peripheral refraction was measured in 20 myopic and 20 control adult subjects. Both central and peripheral refraction (20° nasal and temporal eccentricity) were measured using RET and open-field AR. Differences in the median central spherical equivalent (SE), median RPR, and median J45/J180 power vectors between the RET and AR techniques were analyzed. Moreover, Bland – Altman plots were used to assess the agreement between RET and AR methods for RPR measurements in MG. Results: For MG, the median RPR values were positive (hyperopic shift), and no significant differences were observed between the RET and AR techniques with respect to RPR measurement. In addition, we did not observe any significant differences in the RPR values between the nasal and temporal eccentricities for either the RET or AR technique for myopic subjects. There was also a significant correlation and agreement between the RET and AR technique for RPR measurements. With respect to central refraction, the median SE was slightly more positive for the RET than for the AR technique. Inside the CG, we also found significant correlation between the RET and AR technique for RPR measurements, and we observed a myopic shift in peripheral eccentricities. Conclusion: Our results show that retinoscopy may be a useful tool for objective measurements of RPR in myopic subjects and may be used interchangeably with the open-field AR method in everyday clinical practice. (AU)

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.

Objective and subjective assessment of accommodative insufficiency.

SIGNIFICANCE: A variety of subjective and objective procedures are available to measure the amplitude of accommodation. However, it is unclear whether the standard criterion of Hofstetter's minimum minus 2 D can be used to diagnose accommodative insufficiency with each of these techniques. PURPOSE: The use of objective dynamic retinoscopy and three subjective techniques to diagnosis accommodative insufficiency was examined. METHODS: A total of 632 subjects between 8 and 19 years of age were enrolled. Accommodative lag, monocular accommodative facility, and subjective (push-up, modified push-down, and minus lens) and objective (dynamic retinoscopy) amplitude of accommodation were quantified. Accommodative insufficiency was diagnosed based on Hofstetter's minimum minus 2 D for each subjective method, as well as adding an additional subjective criterion (either accommodative lag exceeding 0.75 D or monocular accommodative facility falling below the age-expected norms). RESULTS: The prevalence of accommodative insufficiency was lowest and highest with the push-up (7.9 and 1%) and dynamic retinoscopy (94 and 12%) procedures when measured without and with the additional subjective criteria, respectively. Comparing the validity of dynamic retinoscopy against the traditional criterion, moderate to low sensitivity and high specificity were found. However, adding the additional subjective criteria improved the findings with moderate to high sensitivity and high specificity. Using a cutoff for dynamic retinoscopy of 7.50 D showed moderate diagnostic accuracy based on likelihood ratios. CONCLUSIONS: It is clear that a revised definition of accommodative insufficiency is required, which must include the method of assessing accommodation. The various objective and subjective methods for quantifying the amplitude of accommodation are not interchangeable, and subjective assessment does not provide a valid measure of the accommodative response.

Efficacy of 3D-printed eye model to enhance retinoscopy skills.

We conducted a prospective study to evaluate the efficacy of simulation-based education using a three-dimensional (3D)-printed schematic eye model in improving the retinoscopy refraction skills of medical students. A schematic eye model was printed using a fused deposition modeling-based 3D printer. Twenty medical students randomized into 3D (n = 10) and control (n = 10) groups received a 1-h lecture on the principles and methods of manifest refraction and were shown how to use the retinoscope and sciascope bars. The 3D group additionally attended a tutorial on the schematic eye. Both groups performed refractive examinations on four eyes of volunteer patients, and the results were recorded as a baseline. Instructor feedback and refraction practice was provided with the 3D group or with control group. To account for subject fatigue, patients spent no more than 8 min on the examination. After a 1-h break to allow for fatigue and familiarity, refraction tests were repeated on four randomly selected eyes of patients. Students' refraction readings were compared with the autorefractor values using a spherical equivalent value and blur strength. All participants measured the time required to complete the refraction test and reported their subjective confidence in the results of each refraction test. Refractive errors before and after training did not differ between the control and 3D groups, with a significant improvement in errors observed in both groups (p = 0.005 and 0.008, respectively). The time to complete refraction before and after training did not differ between the two groups, both of which showed a significant reduction in time (p = 0.005 and 0.028, respectively). Pre- and post-training confidence scores for the accuracy of each refraction on a 10-point Likert scale were not significantly different. However, when comparing score changes between pre- and post-training, only the control group showed a significant increase in confidence (p = 0.005). Tests for the non-inferiority of refractive errors after training indicated that the 3D group was non-inferior to the control group. In conclusion, training in retinoscopy refraction skills using a 3D-printed eye model resulted in significant improvement in accuracy and speed compared to practice with real patients. Except for better confidence in the control group, schematic eye model training was not inferior to practice with real patients.

Training in retinoscopy: learning curves using a standardized method.

BACKGROUND: Retinoscopy is one of the most effective objective techniques for evaluating refractive status, especially in non-cooperative patients. However, it presents a slow learning curve that often leads to student frustration. With the current Covid-19 pandemic and the need for social isolation, clinical education based on simulation has become more relevant. Therefore, we implemented retinoscopy laboratories and learning protocols to reduce student stress and learning time. METHODS: We conducted a study to evaluate the retinoscopy learning curve using a new training protocol proposal. One hundred trainees were assessed in four stages, corresponding to 08, 12, 16, and 20 hours of training. Six different refractive defects were used trying to reproduce frequent conditions of care. The time spent on the assessment was not considered as additional training time. To analyze the data, we used non-parametric statistics and linear regression to assess the variables associated with training time and performance rate. RESULTS: The mean performance score at 08 hrs was 32.49% (±16.69 SD); at 12 hrs was 59.75% (±18.80 SD); at 16 hrs was 70.83% (±18.53 SD) and at 20 hrs was 84.26% (±13.18 SD). Performance at 12 hrs was significative higher than 08 hrs of training, but did not show significant differences with the performance rate at 16 and 20 hrs. We found a strong positive correlation between performance and training time in retinoscopy (R = 0.9773, CI: 0.2678 - 0.9995 p = 0.0227). CONCLUSION: This study showed that an increasing number of hours of practice positively correlates with performance in retinoscopy. The elaboration of a protocol and standardization of performance per hour also allowed us to estimate that a minimum of 13.4 hrs of practice is required to achieve 60% performance. Using the resulting formula, it is possible to determine the number of hours of retinoscopy practice are necessary to reach a certain level of performance.

Comparison of the new self-contained darkroom refractive screener versus table-top autorefractor and cycloplegia retinoscopy in detecting refractive error.

PURPOSE: By comparing the results of the new self-contained darkroom refractive screener (YD-SX-A) versus table-top autorefractor and cycloplegic retinoscopy, to evaluate the performance of the YD-SX-A in detecting refractive error in children and adolescents and then judge whether it can be used in refractive screening. METHODS: Cross-sectional study. 1000 participants between the ages of 6 and 18 who visited the Optometry Center of the People's Hospital of Guangxi Zhuang Autonomous Region from June to December 2022 were selected. First, participants were instructed to measure their diopter with a table-top autorefractor (Topcon KR8800) and YD-SX-A in a noncycloplegic setting. After cycloplegia, they were retinoscopy by a professional optometrist. The results measured by three methods were collected respectively. To avoid deviation, only the right eye (1000 eyes) data were used in the statistical analysis. The Bland-Altman plots were used to evaluate the agreement of diopters measured by the three methods. The receiver operating characteristic (ROC) curves was used to analysis effectiveness of detecting refractive error of YD-SX-A. RESULTS: The average age of participants was 10.77 ± 3.00 years, including 504 boys (50.4%) and 496 girls (49.6%). When YD-SX-A and cycloplegia retinoscopy (CR) were compared in the myopia group, there was no statistical difference in spherical equivalent (SE) (P > 0.05), but there was a statistical difference in diopter spherical (DS) and diopter cylinder (DC) (P < 0.05). Comparing the diopter results of Topcon KR8800 and CR, the difference between each test value in the myopia group was statistically significant (P < 0.05). In the hyperopia group, the comparison between YD-SX-A and CR showed no statistically significant differences in the DC (P > 0.05), but there were significant differences in the SE and DS (P < 0.05). In the astigmatism group, the SE, DS, and DC were statistically different, and the DC of YD-SX-A was lower than that of CR and Topcon KR8800. Bland-Altman plots indicated that YD-SX-A has a moderate agreement with CR and Topcon KR8800. The sensitivity and specificity of YD-SX-A for detecting myopia, hyperopia and astigmatism were 90.17% and 90.32%, 97.78% and 87.88%, 84.08% and 74.26%, respectively. CONCLUSION: This study has identified that YD-SX-A has shown good performance in both agreement and effectiveness in detecting refractive error when compared with Topcon KR8800 and CR. YD-SX-A could be a useful tool for large-scale population refractive screening.

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.

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.

Evaluation of a Pilot Protocol for Detecting Infant Hyperopia.

SIGNIFICANCE: Highly hyperopic children are at greater risk for developing conditions such as strabismus, amblyopia, and early literacy and reading problems. High hyperopia is a common finding in infants in a pediatric medical practice, and early detection can be done effectively in that setting with tropicamide autorefraction. PURPOSE: This study aimed to evaluate the effectiveness of a pilot screening program to detect high hyperopia in 2-month-old infants in a pediatric medical practice in Columbus, Ohio. METHODS: Cycloplegic refractive error (1% tropicamide) was measured by retinoscopy and autorefraction with the Welch Allyn SureSight (Welch Allyn/Hillrom, Skaneateles Falls, NY) in 473 infants (55.4% female) who were undergoing their 2-month well-baby visit at their pediatrician's medical practice. Cycloplegic retinoscopy (1% cyclopentolate) was repeated at a subsequent visit in 35 infants with ≥+5.00 D hyperopia in the most hyperopic meridian during the screening. RESULTS: Twenty-eight infants (5.9%) had high hyperopia (spherical equivalent, ≥+5.00 D), and 61 (12.9%) had high hyperopia (≥+5.00 D in at least one meridian of at least one eye) by retinoscopy with 1% tropicamide. The mean ± standard deviation spherical equivalent tropicamide cycloplegic refractive error measured with retinoscopy was +2.54 ± 1.54 D (range, -3.25 to +7.00 D) and with SureSight was +2.29 ± 1.64 D (range, -2.90 to +7.53 D). Retinoscopy done using 1% cyclopentolate was 0.44 ± 0.54 D more hyperopic in spherical equivalent than with 1% tropicamide ( P < .001). CONCLUSIONS: High hyperopia was a common finding in 2-month-old infants in a pediatric medical setting that could be detected effectively by cycloplegic autorefraction using tropicamide. Greater cooperation between pediatric primary vision and medical care could lead to effective vision screenings designed to detect high hyperopia in infants.

Using evidence-based psychological approaches to accommodation anomalies.

INTRODUCTION: Accommodation anomalies are frequently caused or exacerbated by psychological problems such as anxiety. Patients share many features with those with other anxiety based somatic symptoms such as stomach-ache, palpitations and headaches. They can be difficult to treat, and the ophthalmic literature rarely goes beyond diagnosis and ocular treatment. This study reports characteristics and outcomes of a short case series of patients with accommodation spasms and weaknesses assessed objectively, and outlines a psychological approach to treatment. METHODS: 23 patients (13 severe accommodative weakness or "paralysis," 10 accommodative spasm) aged between 8-30 years, were referred to our laboratory after diagnosis by their referring clinician and exclusion of pathology or drug-related causes. Their accommodation and convergence were assessed objectively with a laboratory photorefractive method, as well as by conventional orthoptic testing and dynamic retinoscopy. All interactions with the patients used an evidence-based psychological approach, to give them insight into how stress and anxiety can cause or exacerbate eye symptoms and help them to break a vicious cycle of anxiety and risk of deterioration. RESULTS: 83% were female and 57% had previously diagnosed anxiety or dyslexia (with many more acknowledging being "worriers"). Inconsistency of responses was the rule and all showed normal responses at some time during their visit. Responses were poorly related to the visual stimuli presented and objective responses often differed from subjective. Dissociation between convergence and accommodation was more common, compared to our large, previously reported, control groups. No participant had true paralysis of accommodation. Responses often improved dramatically within one session after discussion and explanation of the strong relationship between anxiety and accommodative anomalies. None have returned for further advice or treatment. CONCLUSIONS: Our approach explicitly addresses psychological factors in causing, or worsening, accommodation (and co-existing convergence) anomalies. Many of these patients do not realize that a certain amount of blur is normal in everyday life. Ocular symptoms are often a sign of anxiety, not the primary problem. By recognizing this, patients can be helped to address the triggering issues and symptoms often subside or resolve spontaneously. Well-meaning professionals, offering only ocular treatments, can deflect attention away from the real cause and can unwittingly be making things worse.

Bifocal use in hyperopic anisometropic amblyopia treated with atropine: a proof-of-concept randomized trial.

OBJECTIVES: To investigate the effect of bifocal wearing in the amblyopic eye when atropine is used in the sound eye for the treatment of hyperopic anisometropic amblyopia. METHODS: Children 4-8 years old were randomly assigned to bifocal + atropine (n = 16) or only atropine (control, n = 19) groups of treatment in a proof-of-concept study. Measurements included visual acuity (logMAR), prism and cover test, stereoacuity (Randot preschool or Randot circles), contrast sensitivity (MARS test), accommodation (Grand Seiko WAM5500 and dynamic retinoscopy), retinoscopic and subjective refraction, before starting treatment and at 6 months, except accommodation, which was remeasured at 9-11 months. Main outcome measure was change in logMAR lines of visual acuity, and secondary outcome measures were change in stereoacuity and contrast sensitivity in the amblyopic eye, at 6 months. RESULTS: Improvement in visual acuity of the amblyopic eye was significantly better (p = 0.04) in the atropine plus bifocal (3.3 ± 0.9 logMAR lines) than in the atropine only group (2.6 ± 0.8 logMAR lines), whereas change in stereoacuity and contrast sensitivity was not significantly different between the two groups. Differences in accommodative gain, which was impaired in the amblyopic compared to the sound eye, before treatment, decreased after treatment, in the atropine group (0.62 ± 0.16 vs 0.79 ± 0.2, p = 0.3), and atropine + bifocal group (0.69 ± 0.15 vs 0.82 ± 0.2, p = 0.4). CONCLUSIONS: Use of bifocal lens add in the amblyopic eye of children with hyperopic anisometropic amblyopia, treated by atropine penalization, is beneficial in the follow-up period of 6 months.

Clinical correlation between automated vision screening under cycloplegia and retinoscopy in young children.

PURPOSE: To evaluate the clinical performance of the Spot Vision Screener and establish clinical correlations between automated screening and retinoscopy following induction of cycloplegia in preverbal children. METHODS: In this prospective, cross-sectional study, children aged 6-36 months were evaluated using the Spot Vision Screener. A complete ophthalmologic examination, including cycloplegic refraction assessment, was performed, followed by repeat spot vision screening and retinoscopy in all cases to establish correlations regarding hypermetropia, myopia, and astigmatism following induction of induction cycloplegia. RESULTS: The study included 185 children. The sensitivity of the automated screener after cycloplegia was 100% (95%CI: 85.18-100%), and specificity was 87.04% (95%CI: 80.87-91.79%). Positive and negative predictive values were 52.27% (42.36-62.01%) and 100%, respectively. Compared to retinoscopy, the Spot Vision Screener overestimated spherical values by 0.62 D (95%CI: 0.56-0.69) in the right eye and by 0.60 (95%CI: 0.54-0.66) in the left eye and cylindrical values by -0.38 D in the right eye (95%CI: -0.42--0.33) and by -0.39 D in the left eye (95%CI: -0.43--0.34). For overall spherical and cylindrical values, the difference was 0.61 D (95%CI: 0.57-0.65) and -0.38 D (95%CI: -0.41--0.35) in the left and right eyes, respectively. CONCLUSION: A substantial correlation was found between retinoscopy and objective data captured by the device. This shows that technology can be used in conjunction, reaching a more accurate diagnosis and identifying amblyopia risk factors as early as possible. Photoscreening may make a difference at the population level for early screening and intervention.

Comparisons of objective and subjective refraction with and without cycloplegia using binocular wavefront optometer with autorefraction and retinoscopy in school-age children.

PURPOSE: To compare school-age children's objective and subjective refraction using a binocular wavefront optometer (BWFOM) with autorefraction and retinoscopy before and after cycloplegia. METHODS: Eighty-six eyes from 86 children (6-15 years old) were enrolled in this cross-sectional study. BWFOM objective and subjective refractions were compared with autorefraction and retinoscopy under cycloplegia. BWFOM refraction was evaluated before and after cycloplegia. Measurements were compared using a paired t-test; agreement was assessed using Bland-Altman plots. RESULTS: Under cycloplegia, the sphere, spherical equivalence, and J45 were significantly more negative on BWFOM objective refraction than autorefraction (- 1.39 ± 2.20 D vs. - 1.28 ± 2.23 D, P = 0.003; - 1.84 ± 2.38 D vs. - 1.72 ± 2.43 D, P = 0.001; - 0.02 ± 0.17 D vs. 0.03 ± 0.21 D, P = 0.004). The subjective sphere of BWFOM was less myopic, and the cylinder and the J45 were more negative than those with retinoscopy (- 1.17 ± 2.09 D vs. - 1.25 ± 2.20 D, P = 0.02; - 0.91 ± 0.92 D vs. - 0.76 ± 0.92 D, P < 0.001; - 0.01 ± 0.15 D vs. 0.03 ± 0.21 D, P = 0.028). For both BWFOM objective and subjective refraction, sphere and spherical equivalence with noncycloplegia were more myopic than those with cycloplegia (objective: - 1.76 ± 2.10 D vs. - 1.39 ± 2.20 D, - 2.21 ± 2.30 D vs. - 1.84 ± 2.38 D, P < 0.001; subjective: - 1.57 ± 1.92 D vs. - 1.17 ± 2.09 D, - 2.01 ± 2.13 D vs. - 1.62 ± 2.27 D, P < 0.001). Bland-Altman plots showed good agreement in spherical equivalence between BWFOM objective refraction and autorefraction (mean difference = 0.12 D, 95% confidence interval [CI] - 0.52 to 0.76), subjective refraction with retinoscopy (mean difference = - 0.01 D, 95% CI - 0.65 to 0.64), and BWFOM refractions with or without cycloplegia (objective: mean difference = - 0.37 D, 95% CI - 1.31 to 0.57; subjective: mean difference = - 0.39 D, 95% CI - 1.30 to 0.51). The time cost by BWFOM was significantly less than the total time of autorefraction and retinoscopy (264.88 ± 90.67 s vs. 315.89 ± 95.31 s, P < 0.001). CONCLUSION: BWFOM is a new device that realizes both objective and subjective refraction. For children's refractive errors, it is more convenient and quicker to obtain the proper prescription at a 0.05-D interval, and it is more accurate than autorefraction and retinoscopy under cycloplegia.

Identification of ocular refraction based on deep learning algorithm as a novel retinoscopy method.

BACKGROUND: The evaluation of refraction is indispensable in ophthalmic clinics, generally requiring a refractor or retinoscopy under cycloplegia. Retinal fundus photographs (RFPs) supply a wealth of information related to the human eye and might provide a promising approach that is more convenient and objective. Here, we aimed to develop and validate a fusion model-based deep learning system (FMDLS) to identify ocular refraction via RFPs and compare with the cycloplegic refraction. In this population-based comparative study, we retrospectively collected 11,973 RFPs from May 1, 2020 to November 20, 2021. The performance of the regression models for sphere and cylinder was evaluated using mean absolute error (MAE). The accuracy, sensitivity, specificity, area under the receiver operating characteristic curve, and F1-score were used to evaluate the classification model of the cylinder axis. RESULTS: Overall, 7873 RFPs were retained for analysis. For sphere and cylinder, the MAE values between the FMDLS and cycloplegic refraction were 0.50 D and 0.31 D, representing an increase of 29.41% and 26.67%, respectively, when compared with the single models. The correlation coefficients (r) were 0.949 and 0.807, respectively. For axis analysis, the accuracy, specificity, sensitivity, and area under the curve value of the classification model were 0.89, 0.941, 0.882, and 0.814, respectively, and the F1-score was 0.88. CONCLUSIONS: The FMDLS successfully identified the ocular refraction in sphere, cylinder, and axis, and showed good agreement with the cycloplegic refraction. The RFPs can provide not only comprehensive fundus information but also the refractive state of the eye, highlighting their potential clinical value.

Effects of corneoconjunctival transposition, posterior lamellar keratoplasty and modified deep lamellar endothelial keratoplasty on streak retinoscopy in equine cadaver eyes.

OBJECTIVE: Evaluate the effects of corneoconjunctival transposition (CCT), posterior lamellar keratoplasty (PLK) and modified deep lamellar endothelial keratoplasty (DLEK) on streak retinoscopy in equine cadaver eyes. METHODS: Intraocular pressure (IOP) was maintained at 25 ± 3 mmHg in 35 equine cadaver eyes. Streak retinoscopy was performed prior to (NO VISCO) and following (VISCO) intracameral injection of 1.0 ml of viscoelastic. Following optical coherence tomography (OCT), an axial CCT [n = 11] or PLK [n = 12], or peripheral DLEK [n = 12] was performed. Streak retinoscopy and OCT were repeated postoperatively. RESULTS: Postsurgical net meridional and spherical refraction for CCT [Horizontal (H): 3.4 (95% CI 2.4-4.4) diopters (D), p < .001, Vertical (V): 3.5 (95% CI 2.7-4.4) D, p < .001, Spherical: 3.5 (95% CI 2.6-4.3) D, p < .001] and PLK [H: 3.2 (95% CI 2.2-4.1) D, p < .001, V: 2.8 (95% CI 2.0-3.6) D, p < .001, Spherical: 3.0 (95% CI 2.2-3.8) D, p < .001] were significantly increased from presurgical (VISCO) values. No difference between presurgical (VISCO) and postsurgical values were identified for the DLEK. Postoperative OCT revealed space between anterior and posterior corneal grafts and corneal undulation associated with suture placement. CONCLUSION: Meridional and spherical refraction had a hyperopic shift following CCT and PLK, with a significantly higher value in the vertical meridian for the CCT. Pre- and postoperative refraction was not significantly different for the DLEK. This supports that the DLEK has a lesser effect on immediate postoperative refraction compared with CCT or PLK.

Wavefront aberrometry repeatability and agreement-A comparison between Pentacam AXL Wave, iTrace and OPD-Scan III.

INTRODUCTION: To compare intrasession agreement and repeatability of wavefront aberration measurements from three different aberrometers obtained using Hartmann-Shack, ray tracing and automated retinoscopy methods, as well as their interdevice agreement. METHODS: Three consecutive measurements were obtained using the Pentacam AXL Wave, the iTrace and the OPD-Scan III in 47 eyes of 47 patients. Wavefront refractions, root mean square of total aberrations (RMS total), RMS of higher-order aberrations (HOA) and second-, third- and fourth-order HOAs were exported for 4-mm pupils. Wavefront refractions were converted into vector components: M, J0 and J45 . Intrasession agreement and repeatability were evaluated using intraclass correlation coefficients (ICCs) and repeatability coefficients (RCs); interdevice agreement was assessed using the Bland-Altman method. RESULTS: The intrasession agreement and repeatability of RMS HOA were comparable between the three devices; both the Pentacam AXL Wave and the OPD-Scan III had better intrasession agreement and repeatability for the RMS total than the iTrace (p ≤ 0.02). Intrasession repeatability for the majority of second- and third-order aberrations was better on the Pentacam AXL Wave than on the iTrace (p ≤ 0.01) and OPD-Scan III (p ≤ 0.04), although their agreement and repeatability in spherical aberration were comparable (p ≥ 0.24). Significant systematic differences and proportional bias were detected for almost all refraction power vectors and Zernike coefficients among the three devices. CONCLUSIONS: In this study, all three devices provided good-to-excellent agreement for aberration measurements. Most of the individual Zernike's components were not exchangeable between different aberrometers. Their relative intrasession performance in agreement and repeatability varied significantly across different ocular aberration parameters.

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.