Prism Diopters Of Orthophoria Research Articles

Acquired comitant esotropias – comparison of surgical outcomes of accommodative vs non-accommodative types

ABSTRACT Purpose: To compare the motor and sensory outcomes of strabismus surgery and the factors affecting surgical success in acquired acute non-accomodative esotropia (ANAET) and partially accommodative refractive esotropia (pARET). Methods: A retrospective chart review of patients with ANAET and pARET who underwent unilateral or bilateral horizontal rectus muscle surgery between January 2020 and December 2021 was conducted. Patients with postoperative follow-up of at least six weeks were included. Patients with pattern deviation, lateral incomitance, and near-distance disparity were excluded. Motor success was defined as a postoperative deviation within eight prism diopters of orthophoria. Sensory success was defined as presence of binocular single vision (BSV) for both distance and near (Worth four dot test). The effect of factors like age at onset, age at surgery, amblyopia before surgery, duration of squint before treatment, presence or absence and magnitude of vertical deviation, preoperative angle of deviation, and spherical equivalent on the motor and sensory success in each group were analyzed and compared. Results: 38 patients with ANAET and 33 patients with pARET were included. The mean age of onset of esotropia was 8.55 ± 4.65 years and 4.39 ± 2.27 years (p < .001) and the mean age at surgery was 10.62 ± 4.99 years and 7.89 ± 2.84 years (p = .006) in the ANAET and the pARET group respectively. The mean duration of the final follow-up was 38.51 weeks in the ANAET and 48.68 weeks in the pARET group (p = .089). Patients were successfully aligned for both distance and near in 81.5% of patients in the ANAET and 78.9% of patients in the pARET group at the final follow-up (p. 0.775). A BSV for both distance and near at the final follow-up was seen in 81.2% vs 66.6% of patients in the ANAET and the pARET group respectively (p = .25). A good near stereoacuity (<120 arcsecs) was seen in 60.6% and 41.9% of the ANAET and the pARET groups respectively (p = .175). The percentage of patients in the ANAET group who had orthophoria, any esodeviation, and any exodeviation for distance at the final follow-up was 63.1%, 34.2% and, 2.6%. The percentage of patients in the pARET group in similar categories was 36.3%, 42.4% and, 21.2%. None of the demographic and preoperative factors were found to affect the surgical outcomes in the two groups. Conclusions: The motor and sensory outcomes were similar in the two groups. A higher proportion of ANAET patients remained orthophoric during the follow-up. The patients in the pARET group showed a tendency toward exodrift.

Long-Term Binocularity in Accommodative Esotropia

Purpose: To find clinical factors related to the long-term outcome of binocularity in accommodative esotropia. Methods: Forty-nine patients with accommodative esotropia who were followed over 5 years after successful optical alignment within 8 prism diopters of orthophoria at near and distance with glasses including bifocals were included. The patients who had stereo acuity better than 50 seconds/arc and central fusion without suppression scotoma at the final visit were divided into the bifoveal fusion group and the others were divided into the peripheral fusion group. Clinical factors were analyzed between the two groups (Chi-square test, student t-test). Results: Of the 49 patients, 15 patients were included in the bifoveal fusion group and 34 patients were included in peripheral fusion group. Mean follow-up was 88.9 ± 25.4 months. Clinical factors that were significantly related to the bifoveal fusion group were older age of onset, shorter duration of misalignment, intermittent esotropia at the initial visit and after initial optical correction, smaller residual deviations at distance after initial optical correction and at the final visit, and lesser amblyopia. Conclusions: To obtain better levels of long-term binocularity, optical correction should be done as early as possible, before the presence of constant eye misalignment or amblyopia, and the residual esodeviations after optical correction should be kept as small as possible. J Korean Ophthalmol Soc 2015;56(5):759-763

Outcome Study of Graded Unilateral Medial Rectus Recession for Small to Moderate Angle Esotropia

To report an outcome study of 123 consecutive patients treated by graded unilateral medial rectus recession for small to moderate angle esotropia over an 8-year period with a minimum follow-up of 6 months. The records of patients who underwent unilateral medial rectus recession for constant esotropia measuring 15 to 35 prism diopters (PD) were reviewed. Unilateral medial rectus recession of 5.0, 5.5, 6.0, 6.5, and 7.0 mm was performed for 15 to 18, 19 to 20, 21 to 25, 26 to 30, and 31 to 35 PD of esodeviation, respectively. Postoperative follow-up was at least 6 months. Successful alignment was defined as ±5 PD of orthophoria in primary and lateral gaze while viewing distant and near accommodative targets. The eyes of 96.8% of the patients were successfully aligned and the average deviation corrected was 17.33 ± 1.16 PD for 5 mm, 18.57 ± 2.51 PD for 5.5 mm, 23.67 ± 4.91 PD for 6 mm, 26.68 ± 3.87 PD for 6.5 mm, and 31.93 ± 3.26 PD for 7 mm unilateral medial rectus recession at 6-month follow-up. Seventy-four patients (83.2%) with more than 6 months of follow-up achieved successful alignment, 14 (15.7%) were under-corrected, and 1 (1.1%) was overcorrected. Successful alignment was achieved in most esotropic patients treated by the graded unilateral medial rectus recessions. The surgical guidelines provide a reference for the treatment of small to moderate angle esotropia.

Combined Eyelid and Strabismus Surgery: Examining Conventional Surgical Wisdom

To determine whether satisfactory results of both eyelid surgery and strabismus surgery can be obtained when these procedures are performed in the same setting in selected patients. Nine patients (16 eyelids) who had undergone surgery in the same setting for eyelid malposition and strabismus of the horizontal rectus muscles, with or without concurrent vertical rectus muscle surgery, were retrospectively reviewed. Eyelid malposition surgery success was defined as a postoperative margin reflex distance (MRD1) within 1 mm of the target. Strabismus surgery success was defined as a postoperative deviation within 8 prism diopters of orthophoria or a decrease in binocular diplopia if the patient had a less than 8 prism diopters deviation in primary gaze preoperatively. Eyelid retraction repair was performed on 13 upper eyelids, levator advancement was performed on 2 eyelids, and frontalis suspension was performed on 1 eyelid. Four patients underwent bilateral medial rectus recession and the remaining 5 patients received varying strabismus surgery. Four patients received adjustable sutures. Mean follow-up was 11 months. Postoperatively, 13 of 16 eyelids (81%) achieved an MRD1 within 1 mm of the target. Eight of 9 patients (89%) demonstrated satisfactory strabismus correction. Combined eyelid malposition and strabismus surgery can be successfully performed in selected cases, particularly when the strabismus surgery involves the horizontal rectus muscles. Combined surgery is not recommended in cases that do not involve the horizontal rectus muscles.

Unaugmented Vertical Muscle Transposition Surgery for Chronic Sixth Nerve Paralysis

Introduction: Chronic sixth nerve palsy can cause incapacitating diplopia requiring vertical muscle transposition surgery. Augmentation of surgery, with lateral fixation sutures, medial rectus recession or botulinum toxin injection, is associated with an increased risk of complications. Purpose: Our aim was to evaluate the efficacy and safety of unaugmented full-tendon vertical rectus transposition in chronic sixth nerve paralysis. Methods:Longitudinal study of 21 patients with chronic sixth nerve paralysis of longer than 6 months duration, who underwent superior and inferior recti transposition surgery without medial rectus recession or botulinum toxin injection. Details of surgery, preoperative and postoperative examinations including full orthoptic examination were obtained from an electronic database. Outcomes included the change in angle of deviation, the requirement for further surgery to the medial rectus and postoperative improvement in diplopia. SPSS software (Version 12.0.1, SPSS Inc. Chicago, IL) was used to summarize baseline characteristics and outcomes and to compare preoperative and postoperative deviation (paired t-test). Results: Twenty-one patients (10 (47.6%) men and 11 (52.4%) women) with a mean age of 41 years (range 4 to 74 years) were operated in the period between April 1998 and November 2000. Eighteen patients had unilateral and three had bilateral acquired sixth nerve palsy. Nineteen patients required unilateral surgery and two had bilateral transposition procedures. In patients with unilateral sixth nerve palsy, mean esotropia in primary position before surgery was 46.7 prism-diopters (PD) (95% CI 35.9–57.4 PD) and improved to 14.6 PD after surgery (95% CI 6.4–22.7 PD). The angle of deviation was significantly reduced by an average of 32.1 PD (p < 0.001, paired t-test; 95 % CI 22.6–41.6 PD). Over all, 10 patients (55.6%) had a well-controlled esophoria with a postoperative alignment of within 10 PD of orthophoria without diplopia in the primary position, for distance and near. A further six patients (28.6%) required additional medial rectus recessions to achieve success. The only complication observed was slippage of the inferior rectus in one patient (4.2%), who consequently required further surgery. Conclusion: Botulinum toxin infiltration of the medial rectus in vertical rectus transposition surgery may be unnecessary, incurring cost, additional attendances and interventions for patients. Less than a third of all patients in our series required additional medial rectus recession later.

Sensory Deviations Subsequent to Senile Cataract

To evaluate the effect of extracapsular cataract extraction with posterior chamber intraocular lens (IOL) implantation in patients with sensory deviations subsequent to senile cataract. Twenty patients with dense cataract and associated sensory deviations underwent follow-up between April 1996 and April 1998 after extracapsular cataract extraction with posterior chamber IOL implantation in the deviating eye. All patients underwent follow-up for a minimum period of 6 months. Preoperatively, all patients had a visual acuity of PL positive (perception of light present) and PR (projection of rays) accurate in the deviating eye. Two patients had an esodeviation, and 18 patients had an exodeviation. Postoperatively, all patients had a corrected visual acuity of 20/40 or better in the operated eye at 12 weeks. Nineteen patients had ocular alignment within +/-8 prism diopters of orthophoria at 12 weeks. Sensory deviations subsequent to senile cataract usually resolve spontaneously after cataract surgery if visual gains are 20/40 or better. The prognosis for binocular vision is good.