Refractive surgery as a treatment tool for strabismus: systematic review.

The impact refractive surgery has on preoperative horizontal strabismus is rapidly evolving, and this knowledge can provide valuable clinical context when considering refractive surgery as a treatment for strabismus. 515 studies were identified, of which 26 met the inclusion criteria. Analysis indicated that refractive surgery resulted in an overall decrease in the mean uncorrected postoperative angle of deviation caused partially or fully due to refractive error and highlighted the varied outcome of refractive surgery on nonaccommodative horizontal strabismus with limited evidence to suggest refractive surgery for this type of strabismus. Efficacy of refractive surgery in reducing concomitant horizontal strabismus depends on several factors: type of horizontal ocular deviation, patient age, and extent of refractive error. Refractive surgery can be an effective treatment for refractive accommodative horizontal strabismus in patients with stable, mild to moderate myopia or hyperopia and should be considered with careful patient selection for optimum outcome.

Prevalence of Choroidal Abnormalities and Lisch Nodules in Children Meeting Clinical and Molecular Diagnosis of Neurofibromatosis Type 1.

PURPOSE: To determine the prevalence of choroidal abnormalities (CAs) and Lisch nodules (LNs) in children who met the clinical diagnostic criteria (CDC) alone and those with a molecularly confirmed diagnosis (MCD) of neurofibromatosis type 1 (NF1), and to ascertain any differences between the groups. METHODS: This was a cross-sectional observational study. All children who met the CDC and/or had MCD of NF1 and underwent eye examination were included. At least two CAs or LNs between the two eyes were set as a threshold to define the presence of either abnormality. Frequencies alongside 95% confidence intervals (CIs) were calculated. The relationship between patient age and the presence of LNs and/or CAs was estimated using logistic regression. RESULTS: The study cohort included 94 patients; CAs (64%) were more prevalent than LNs (41%) (0.22; 95% CI, 0.08-0.36; P = 0.0023). The probability of the presence of LNs was lower than that of CAs across all ages (odds ratio = 0.37; 95% CI, 0.20-0.69; P = 0.00173). CAs were exclusively found in 37% of patients and LNs in 16%; 80% had either CAs or LNs, or both. In the CDC group (n = 41), the difference in prevalence (CAs = 68%, LNs = 51%) did not attain statistical significance (0.17; 95% CI, -0.06 to 0.40; P = 0.18). In the MCD group (n = 53), the difference in prevalence (CAs = 60%, LNs = 34%) was significant (0.26; 95% CI, 0.006-0.47; P = 0.023). CONCLUSIONS: CAs were more frequent than LNs in pediatric NF1 patients regardless of age and MCD status. Combining ophthalmological exams with near-infrared imaging will increase the diagnostic reach in pediatric NF1. TRANSLATIONAL RELEVANCE: CAs detected on near-infrared imaging are objective biomarkers in NF1. They are more prevalent and detected earlier in the pediatric population compared with LNs. Hence, the presence of CAs should be routinely ascertained in children suspected with NF1.

Ocular motility disturbances after glaucoma drainage device implantation for paediatric glaucoma: a cross-sectional study.

AIM: To grade extraocular motility in the field of action of each extraocular muscle following superotemporal glaucoma drainage device (GDD) implantation in a paediatric population and to investigate which drainage device (Ahmed vs Baerveldt) yields less extraocular motility disturbance. METHODS: Cross-sectional study of children with a GDD implanted consecutively by a single surgeon who underwent ocular motility examination by two masked orthoptists. Ductions in the cardinal positions were graded. Ocular alignment, visual acuity, binocularity, stereopsis and intraocular pressure were also measured, and patient charts were reviewed. RESULTS: Thirty children each had one eye included. Twenty-one eyes had an Ahmed GDD and 9 had a Baerveldt GDD. Mean time between GDD insertion and ocular motility exam was 68 months in the Ahmed group and 19 months in the Baerveldt group. Exotropia was present in 46% and vertical heterotropia in 46% of children post-GDD insertion. Thirty-three percent of eyes had a moderate or severe limitation of elevation in abduction, 30% of elevation in adduction, 10% of abduction and 10% of adduction. There was a trend towards more eyes in the Ahmed group (62%) having at least a moderate limitation in ocular motility (-2 or worse; scale -1 to -4) compared with the Baerveldt group (22%). CONCLUSION: Strabismus is common in children with GDDs. Our motility and alignment findings are consistent with either a mass effect of the device and bleb and/or scarring beneath the plate in the quadrant of the GDD causing dysmotility, most commonly limitation towards the GDD.

Documentation of the Development of Various Visuomotor Responses in Typically Reared Kittens and Those Reared With Early Selected Visual Exposure by Use of a New Procedure.

A new procedure was used to study the development of gaze (responses to moving targets or laser spots in normal kittens, those that had been reared in total darkness to 6 weeks of age, and others that received a period of monocular deprivation (MD). Gaze responses were observed to all stimuli in normal kittens at between 25-30 days of age and striking responses occurred on the same day or the next. Despite slow acquisition of spatial vision in the dark reared kittens over 3 months, they were able to follow and even strike at moving visual stimuli within a day of their initial exposure to light. By contrast, for a week following a period of MD, kittens showed no gaze or striking responses to moving stimuli when using their previously deprived eye. The very different profiles of acquisition of visuomotor skills and spatial vision in visually deprived kittens point to a dissociation between the neuronal populations that support these functions.

Diagnostic occlusion test for acquired esotropia.

OBJECTIVE: To assess the effect of the 45-minute diagnostic occlusion test (DOT) on the measured esodeviation in patients with acquired esotropia. METHODS: After the routine ophthalmic examination, 67 patients with acquired esotropia were randomly assigned to either the patch group (37 subjects) or the control group (30 subjects). For both groups the mean distance and near deviations before and after 45 minutes were compared. RESULTS: The mean pre- and post-DOT measurement at distant target for the patch group was an esodeviation of 6.7 ±â€…7.5 prism diopters (PD) and 13.2 ±â€…11.7 PD, respectively. The 45-minute DOT induced an average increase of the esotropia of 6.4 ±â€…5.9 PD in the patch group (p = 0.0001). For the control group, the first and second mean measurement were similar, 9.2 ±â€…7.6 PD and 9.1 ±â€…6.5 PD, respectively (p = 0.103). The mean pre- and post-DOT esodeviation at near distance for the patch group were 10.1 ±â€…10.1 PD and 18.7 ±â€…13.7 PD (p = 0.001). Following the DOT, >5 PD change was noted in 26 (70.1%) from a near distance target (p = 0.001). For the control group, the mean near first and second measurements were 13.9 PD and 15.0 PD, respectively. CONCLUSION: Performing DOT in acquired esodeviations may help to reveal the full deviation and ultimately decrease the risk of surgical undercorrection by eliminating tonic fusional divergence. The DOT can be applied clinically for acquired esotopia to accurately measure the angle of deviation.

Bifocals Fail to Improve Stereopsis Outcomes in High AC/A Accommodative Esotropia.

PURPOSE: To assess whether stereopsis outcomes of patients with accommodative esotropia with high accommodative convergence/accommodation relationship (AC/A) were improved after treatment with bifocal glasses compared with single-vision lenses. DESIGN: Retrospective cohort study. PARTICIPANTS: Patients with high AC/A accommodative esotropia; evidence of stereopsis, binocularity (on Worth 4-dot testing), or improvement in near angle with +3.00 D lenses; and at least 4 years of records available for review, who were seen in the Department of Ophthalmology at Boston Children's Hospital between 2006 and 2014. METHODS: Use of bifocal or single-vision glasses. Charts were reviewed retrospectively. Stereopsis was log transformed for statistical analysis. Linear (for stereopsis) or logistic (for surgery) regression was used to control for confounders. MAIN OUTCOME MEASURES: Stereopsis at final follow-up, difference in stereopsis between final and initial visits, and progression to strabismus surgery. Secondary outcomes included final near and distance deviations. RESULTS: Of the 180 patients who met inclusion criteria, 77 used bifocals and 103 used single-vision lenses. Bifocals did not improve stereopsis outcomes compared with single-vision lenses. In both groups, stereopsis was similar at the initial and final visits, with similar improvement in both groups. Children in the bifocal group had a 3.6-fold higher rate of strabismus surgery than children in the single-lens group (P = 0.04.) Additionally, children in the bifocal group had near deviations 4 PD larger than those with single lenses at final follow-up, even after controlling for age and initial deviation (P = 0.02). These results did not change if surgical patients were eliminated or in the subgroup with initial distance deviation of 0 PD in full hyperopic correction. CONCLUSIONS: Despite their widespread use, there is no evidence that bifocals improve outcomes in children with accommodative esotropia with high AC/A. In our retrospective review, children with bifocals had higher surgical rates and a smaller improvement in near deviation over time. Although our results suggest that eliminating bifocals could reduce the cost and complexity of care while potentially improving quality, prospective, randomized controlled trials are needed to determine whether a change in practice is warranted.

Recovery of visual functions in amblyopic animals following brief exposure to total darkness.

KEY POINTS: Occlusion of one eye of kittens (monocular deprivation) results in a severe and permanent loss of visual acuity in that eye, which parallels closely the vision loss characteristic of human amblyopia. We extended earlier work to demonstrate that amblyopic vision loss can be either blocked or erased very fast by a 10 day period of total darkness following a period of monocular deprivation that begins near birth and extends to at least 8 weeks of age. The parameters of darkness were strict because no visual recovery was observed after 5 days of darkness. In addition, short periods of light introduced each day during an otherwise 10 day period of darkness obliterated the benefits. Despite recovery of normal visual acuity, only one-quarter of the animals showed evidence of having attained normal stereoscopic vision. A period of total darkness may catalyse and improve treatment outcomes in amblyopic children. A 10 day period of total darkness has been shown to either block or erase the severe effects on vision of a prior short period of monocular deprivation (MD) in kittens depending on whether darkness is contiguous or is delayed with respect to the period of MD. We have extended these earlier findings from kittens for which the period of MD began at 1 month and lasted for 1 week to more clinically relevant situations where MD began near birth and lasted for ≥ 6 weeks. Despite the far longer MD and the absence of prior binocular vision, all animals recovered normal visual acuity in the previously deprived eye. As before, when the period of darkness followed immediately after MD, the vision of both eyes was initially very poor but, subsequently, the acuity of each eye increased gradually and equally to attain normal levels in ∼ 7 weeks. By contrast, when darkness was introduced 8 weeks after MD, the visual acuity of the deprived eye recovered quickly to normal levels in just 1 week without any change in the vision of the fellow (non-deprived) eye. Short (15 or 30 min) periods of illumination each day during an otherwise 10 day period of darkness obliterated all the benefits for vision, and a 5 day period of darkness was also completely ineffective. Measurements of depth perception indicated that, despite possessing normal visual acuity in both eyes, only about one-quarter of the animals showed evidence of having attained normal stereoscopic vision.