Mark Steele

The Clinical Utility of Visual-Evoked Potential Acuity Testing

We assessed the clinical utility of objectively measured acuity using visual-evoked potentials. The technique was first standardized in normal emmetropic subjects and then applied to uncorrected myopic subjects. We found that visual-evoked potential acuity could accurately indicate Snellen acuity in emmetropia and corrected myopia; however, the two measures were highly correlated only in those uncorrected myopic subjects with visual acuities of 20/100 or better. In subjects with poorer than 20/200 uncorrected visual acuity caused by myopia, estimates of visual-evoked potential acuity could not be obtained. The correlation between these two measures of visual acuity was also lower in patients with decreased Snellen acuity attributable to retinal or ocular disease. We found that patients with unexplainable claims of decreased visual acuity could be diagnosed as having functional visual loss based on objective visual-evoked potential acuities.

Esotropia associated with high myopia.

Purpose of review The aim of the present article is to describe the pathophysiology of esotropia associated with high myopia, commonly known as heavy eye syndrome, and discuss the preoperative evaluation and surgical options in these complex patients. Recent findings Numerous studies have looked to determine the cause of esotropia in patients with high myopia. Orbital imaging has shown a nasal displacement of the superior rectus muscle and an inferior displacement of the lateral rectus muscle. As such, traditional resection-recession surgery can be ineffective in these patients. Instead, correcting the deviant muscles paths is necessary. Recent studies have shown that loop myopexy with or without medial rectus recession can be performed without sclera fixation sutures to correct the underlying pathophysiology. Summary Heavy eye syndrome or strabismus fixus is a rare restrictive strabismus. Careful preoperative evaluation must be performed in order to correctly diagnose these patients. If posterior globe prolapse with superior and lateral rectus muscle displacement is seen, loop myopexy can be a well tolerated and effective procedure in treating heavy eye syndrome.

The Role of Superior Oblique Posterior Tenectomy Along With Inferior Rectus Recessions for the Treatment of Chin-up Head Positioning in Patients With Nystagmus

PURPOSE To evaluate the clinical outcomes of bilateral superior oblique posterior 7/8th tenectomy with inferior rectus recession on improving chin-up head positioning in patients with horizontal nystagmus. METHODS Medical records were reviewed from 2007 to 2017 for patients with nystagmus and chin-up positioning of 15° or more who underwent combined bilateral superior oblique posterior 7/8th tenectomy with an inferior rectus recession of at least 5 mm. RESULTS Thirteen patients (9 males and 4 females) were included, with an average age of 7.3 years (range: 1.8 to 15 years). Chin-up positioning ranged from 15° to 45° degrees (average: 30°). Three patients had prior horizontal muscle surgeries, 1 for esotropia and 2 for horizontal null zones causing anomalous face turns. Ten patients underwent other concomitant eye muscle surgery: 3 had esotropia, 1 had exotropia, and 2 had biplanar nystagmus null point requiring a horizontal Anderson procedure. Four patients underwent simultaneous bilateral medial rectus tenotomy and reattachment. All patients had improved chin-up positioning. Eight patients had complete resolution, whereas 5 had minimal residual chin-up positioning. Three patients developed an eccentric horizontal gaze null point with compensatory anomalous face turn with onset 2 weeks, 2 years, and 3 years postoperatively. Average follow-up was 42.7 months. No postoperative pattern deviations, cyclodeviations, or inferior oblique overaction were seen. No surgical complications were noted. CONCLUSIONS Bilateral superior oblique posterior 7/8th tenectomy in conjunction with bilateral inferior rectus recession is a safe and effective procedure for improving chin-up head positioning in patients with horizontal nystagmus with a down gaze null point. [J Pediatr Ophthalmol Strabismus. 2018;55(4):234-239.].