Lionel Kowal

Heterozygous mutations of the kinesin KIF21A in congenital fibrosis of the extraocular muscles type 1 (CFEOM1).

Congenital fibrosis of the extraocular muscles type 1 (CFEOM1; OMIM #135700) is an autosomal dominant strabismus disorder associated with defects of the oculomotor nerve. We show that individuals with CFEOM1 harbor heterozygous missense mutations in a kinesin motor protein encoded by KIF21A. We identified six different mutations in 44 of 45 probands. The primary mutational hotspots are in the stalk domain, highlighting an important new role for KIF21A and its stalk in the formation of the oculomotor axis.

Astigmatic change 1 year after excimer laser treatment of myopia and myopic astigmatism

Purpose: To evaluate the surgically induced astigmatism (SIA) 1 year after excimer laser photorefractive astigmatic keratectomy (PARK) and photorefractive keratectomy (PRK). Setting: Royal Victorian Ear and Eye Hospital, Melbourne, Australia. Methods: This study comprised 333 PARK patients and 155 PRK patients treated with a VISX 20/20 excimer laser and followed prospectively for 12 months. Vector analysis of the change in astigmatism was used to calculate the SIA in the PRK group and the percentage of astigmatism corrected in the PARK group. Results: Among patients with low cylinders astigmatic correction varied greatly, particularly in those treated for large amounts of myopia. The spherical PRK treatments yielded a mean induced postoperative astigmatism of 0.47 diopter. There was a linear relationship between this inadvertent SIA and increasing myopia. Conclusion: Excimer laser surgery for myopia creates a low degree of random, unpredictable SIA that may be the result of irregular epithelial thickening during postoperative healing. This creates a background noise of astigmatic change upon which the targeted astigmatic correction is superimposed.

Refractive surgery and strabismus

This review discusses the potential for strabismic complications after refractive surgery for hyperopia, myopia, anisomyopia, astigmatism and monovision, and how to avoid these complications. Guidelines are given for assessing patients with strabismus seeking refractive surgery. Screening tests are suggested that lead to stratification of refractive surgery patients into different risk groups each warranting a different intensity of evaluation.

Diplopia as a complication of laser in situ keratomileusis surgery

A case is presented of a patient with high myopia who developed vertical binocular diplopia after decentred laser in situ keratomileusis (LASIK) surgery with associated decompensation of pre‐existing exophoria into an exotropia. A 40‐year‐old man underwent LASIK surgery for high myopia in his right eye. Preoperatively, he was approximately –26.00/–2.00 × 35° with visual acuity of 6/12–2 in that eye. He also had an asymptomatic exophoria. After LASIK surgery, he achieved a refraction of –3.25/–0.50 × 80° with 6/21 best‐corrected visual acuity. He also developed binocular diplopia. The ablation zone had been decentred upwards and there was also an exo‐ and hypo‐deviation of his right eye. He was able to superimpose the two images in free space with vertical and horizontal prisms. A hard contact lens also resulted in superimposition of the two images. Vertical decentration of the ablation zone can induce a vertical prism effect after LASIK surgery and result in vertical diplopia. This together with abnormal optics also caused loss of best‐corrected vision and decompensation of his pre‐existing exophoria into an exotropia.

Botulinum Toxin in the treatment of strabismus. A review of its use and effects

Botulinum Toxin as a medical therapy was introduced by Dr Alan Scott more than 20 years ago. The first clinical applications of Botulinum Toxin type A (BT-A) were for the treatment of strabismus and for periocular spasms. Botulinum Toxin type A is often effective in small to moderate angle convergent strabismus (esotropia) of any cause, and may be an alternative to surgery in these cases. Botulinum Toxin type A may have a role in acute or chronic fourth and sixth nerve palsy, childhood strabismus and thyroid eye disease. The use of BT-A for strabismus varies enormously in different cities and countries for no apparent reason. Botulinum Toxin type A may be particularly useful in situations where strabismus surgery is undesirable. This may be in elderly patients unfit for general anaesthesia, when the clinical condition is evolving or unstable, or if surgery has not been successful. Botulinum Toxin type A can give temporary symptomatic relief in many instances of bothersome diplopia irrespective of the cause. Ptosis and acquired vertical deviations are the commonest complications encountered. Vision-threatening complications are rare. Repeated use of BT-A is safe.

Refractive surgery and diplopia.

of-life changes for patients. Although only a very small number of potential patients will be at risk of developing strabismic complications after refractive surgery, it is incumbent on the refractive surgeon to be fully educated about these risks. This review provides (i) minimum screening techniques, and (ii) risk stratification guidelines, with the aim of detecting and avoiding potential complications without depriving patients of the potential benefits of refractive surgery.

Predictability of excimer laser treatment of myopia and astigmatism by the VISX Twenty-Twenty

Background: To determine the predictability of excimer laser photorefractive keratectomy (PRK) to correct myopia, astigmatism, or both between −1.00 and −19.00 diopters (D). Setting: Royal Victorian Eye and Ear Hospital, East Melbourne, Australia. Methods: This study comprised 1218 consecutive eyes treated with a VISX TwentyTwenty excimer laser and followed prospectively for 12 months. Low myopia was treated with one ablation zone (6.0 mm), high myopia with two ablation zones (5.0 and 6.0 mm), and extreme myopia with three ablation zones (4.5, 5.0, and 6.0 mm). Maximum spherical treatment was 15.00 D at the corneal plane. Data were analyzed to determine the predictability of the postoperative outcomes by preoperative refraction. Results: Nine hundred eighty eyes (80.5%) were available for the 12 month follow‐up. The predictability of refraction and uncorrected and best corrected visual acuities progressively decreased with increasing myopia, although a comparable percentage of spherical correction was achieved at each diopter of myopia. The likelihood of losing lines of best corrected visual acuity and corneal haze increased with increasing myopia. Conclusion: These data can be used to counsel patients of likely outcomes of excimer laser PRK to correct myopia.

Medial rectus muscle pulley posterior fixation sutures in accommodative and partially accommodative esotropia with convergence excess

BACKGROUND The use of medial rectus pulley posterior fixation sutures to treat esotropia with convergence excess has limited support in the literature. We describe our results using this technique to treat patients with large near-distance disparities. METHODS We retrospectively analyzed records of patients with accommodative or partially accommodative esotropia and convergence excess 13(Δ) or greater treated with bilateral medial rectus muscle recessions augmented by pulley posterior fixation. Surgical doses of recessions were calculated for the mean of distance and near deviations. Primary outcome measures were ocular alignment at distance and near and near-distance disparity. RESULTS A total of 26 patients were identified by the record review. Mean age at surgery was 5.4 years (range, 1.8-11.0 years) and mean follow-up time 12.7 months (range, 1.0-37.6 months). Mean preoperative distance esotropia was 22.9(Δ) (range, 0(Δ)-53(Δ)), with a mean near-distance disparity of 26.4(Δ) (range, 13(Δ)-53(Δ)). At 1 to 3 months postoperatively, mean distance deviation was 0.5(Δ) exotropia (range, 18(Δ) exotropia to 12(Δ) esotropia), with a statistically significant decrease in mean near-distance disparity to 4.5(Δ) (range, 0(Δ)-26(Δ); P < 0.001). Three-quarters of patients (77%) achieved 0(Δ) to 9(Δ) esotropia at 1 to 3 months, with 4 overcorrections for distance and 2 undercorrections for distance and near. At final follow-up 2 patients had persistent exotropia less than 10(Δ). CONCLUSIONS Augmentation of bilateral medial rectus recessions with pulley posterior fixation resulted in a significant decrease in near-distance disparity in this group of patients with accommodative and partially accommodative esotropia and convergence excess, with a low rate of persistent overcorrection for distance.

Effectiveness of a Binocular Video Game vs Placebo Video Game for Improving Visual Functions in Older Children, Teenagers, and Adults With Amblyopia: A Randomized Clinical Trial

Importance Binocular amblyopia treatment using contrast-rebalanced stimuli showed promise in laboratory studies and requires clinical trial investigation in a home-based setting. Objective To compare the effectiveness of a binocular video game with a placebo video game for improving visual functions in older children and adults. Design, Setting, and Participants The Binocular Treatment of Amblyopia Using Videogames clinical trial was a multicenter, double-masked, randomized clinical trial. Between March 2014 and June 2016, 115 participants 7 years and older with unilateral amblyopia (amblyopic eye visual acuity, 0.30-1.00 logMAR; Snellen equivalent, 20/40-20/200) due to anisometropia, strabismus, or both were recruited. Eligible participants were allocated with equal chance to receive either the active or the placebo video game, with minimization stratified by age group (child, age 7 to 12 years; teenager, age 13 to 17 years; and adult, 18 years and older). Interventions Falling-blocks video games played at home on an iPod Touch for 1 hour per day for 6 weeks. The active video game had game elements split between eyes with a dichoptic contrast offset (mean [SD] initial fellow eye contrast, 0.23 [0.14]). The placebo video game presented identical images to both eyes. Main Outcomes and Measures Change in amblyopic eye visual acuity at 6 weeks. Secondary outcomes included compliance, stereoacuity, and interocular suppression. Participants and clinicians who measured outcomes were masked to treatment allocation. Results Of the 115 included participants, 65 (56.5%) were male and 83 (72.2%) were white, and the mean (SD) age at randomization was 21.5 (13.6) years. There were 89 participants (77.4%) who had prior occlusion. The mean (SD) amblyopic eye visual acuity improved 0.06 (0.12) logMAR from baseline in the active group (n = 56) and 0.07 (0.10) logMAR in the placebo group (n = 59). The mean treatment difference between groups, adjusted for baseline visual acuity and age group, was −0.02 logMAR (95% CI, −0.06 to 0.02; P = .25). Compliance with more than 25% of prescribed game play was achieved by 36 participants (64%) in the active group and by 49 (83%) in the placebo group. At 6 weeks, 36 participants (64%) in the active group achieved fellow eye contrast greater than 0.9 in the binocular video game. No group differences were observed for any secondary outcomes. Adverse effects included 3 reports of transient asthenopia. Conclusions and Relevance The specific home-based binocular falling-blocks video game used in this clinical trial did not improve visual outcomes more than the placebo video game despite increases in fellow eye contrast during game play. More engaging video games with considerations for compliance may improve effectiveness. Trial Registration anzctr.org.au Identifier: ACTRN12613001004752

Arterial macroaneurysm of the optic disc

A 64-year-old man presented with an arterial macroaneurysm on the optic disc, an unusual location for retinal arterial macroaneurysm. The macroaneurysm resolved spontaneously without sequelae.