Longitudinal Rehabilitation of Binocular Function in Adolescent Intermittent Exotropia After Successful Corrective Surgery

PurposeTo study the longitudinal rehabilitation of binocular visual function in adolescent intermittent exotropia (IXT) after successful surgery and compare the results with those of a normal population. The role of binocular function in ocular alignment stability was also evaluated postoperatively.MethodsIn this prospective study, 30 adolescents with IXT successfully corrected after 1 month were followed for 12 months, and 30 children with normal vision were enrolled as controls. Stereopsis, the fusional vergence amplitude, sensory fusion, and accommodative flexibility were measured to assess binocular function at baseline and 6 and 12 months postoperatively. The controls were tested once when they were enrolled in the study.ResultsThe deviation was −32.00 ± 8.60 prism diopters (PD) at distance fixation and −36.0 ± 9.10 PD at near fixation preoperatively with an average correction of 28.53 ± 3.79 PD and 30.67 ± 1.34 PD at 1 month postoperatively. Distance stereoacuity and near stereoacuity improved from 1 to 12 months postoperatively (p = 0.025 and p = 0.041, respectively). Compared with the controls, the fusional convergence reserve at distance (p = 0.025) and near (p = 0.033) fixations and fusion reserve ratio at distance (p = 0.000) and near (p = 0.000) fixations remained subnormal, whereas sensory fusion (p = 0.237), distance stereopsis (p = 0.120), and the fusional divergence amplitude at a distance (p = 0.168) were normal. However, no significant correlations were found between binocular functions at 1 month postoperatively and the postoperative drift.ConclusionBinocular function significantly improved from before to after successful corrective surgery and continued to improve from 1 to 12 months postoperatively in adolescents with IXT. No significant correlations were found between binocular functions at 1 month postoperatively and ocular alignment stability.

FREQUENCY OF REFRACTIVE ERROR AND AMBLYOPIA IN STRABISMUS IN PEDIATRIC AGE GROUP

Objective: To see the frequency and compare the type of refractive error and strabismus in amblyopic versus non amblyopic children. Study Design: Comparative cross sectional study. Place and Duration of Study: Armed Forces Institute of Ophthalmology, Rawalpindi, from Jan to Jul 2019. Methodology: The sample population comprised of 250 patients of new or previously diagnosed children with refractive error and strabismus presenting at children eye outdoor patient department of armed forces institute of ophthalmology. Strabismus was diagnosed by the consultant eye specialist on the basis of heterotropia at near or distance fixation. Amblyopia and refracttive error was assessed by a trained optometrist. Patients were classified into amblyopia and non- amblyopia groups. The type of squint and refractive error was noted down along with demographic details. Chi square test was used to assess thesignificance of association between various categorical variables. Results: A total of 250 participants were included with a mean age of 5.00 ± 1.07 years. Out of total, 132 (52.8%) were males while 118 (47.2%) were females. One hundred and fifty (59.5%) patients were suffering from amblyopia while 100 (39.5%) patients were normal with comparable vision in both the eyes. Out of 150 amblyopic patients 134 (89.3%) were suffering from unilateral amblyopia while 16 (10.6%) patients had amblyopia in both the eyes. Out of refractive errors astigmatism was present in 83 (55.3 %) of amblyopia patients while hypermetropia was present in 54 (36%) of the patients. Out of total patients of strabismus, 95 (63.3%) of non-alternating esotropic patients..........

Preoperative Variables Associated with Surgical Outcome for the Correction of Exodeviation

The success rate of exodeviation surgery in existing literature has been shown to be variable. This study sought to determine the success rate of surgery for exodeviation in Atlantic Canada and determine variables associated with surgical outcome. A retrospective chart review was performed, considering patients who had been assessed and surgically treated for exodeviation at the IWK Health Centre between 2011–2018. This study included 176 subjects, aged 1–75 years. Preoperative variables were compared between subjects with successful versus unsuccessful surgical outcomes, using the chi square, Fischer’s exact test and binary logistic regression. A success rate of 43% was determined. Smaller preoperative deviation size at near and distance fixation, as well as the basic type classification were associated with successful operative outcome. Left eye acuity showed a statistically significant association with surgical success outcome. In conclusion, these findings compliment those of previous groups, suggesting exodeviation surgery outcome is variable. Our results add to a growing list of variables implicated in outcomes for these subjects. A smaller deviation preoperatively was associated with success in existing data and in this study, and these findings may suggest a potential role for basic subtype into future exodeviation literature.

Bilateral combined resection-recession of the same rectus muscle versus Fadenoperation for treatment of purely tonic esotropias

Purpose: To compare the efficiency of bilateral combined resection-recession surgery of the medial rectus muscle versus using a modified Fadenoperation for surgical management of esotropias that totally resolve under general anesthesia, which we called “purely tonic” esotropias. Methods: We included 65 unselected consecutive cases of patients with purely tonic esotropias who underwent surgery between October 2017 and 2018. Patients were divided into group I, who underwent a combined resection and recession of medial recti muscles, and group II, who underwent a bilateral medial rectus Fadenoperation using posterior strapping. A satisfactory outcome was defined as deviation ⩽10 prism diopters (PD), at near and distance fixation, between 3 and 6 months postoperatively. Results: Mean initial deviation was in group I, 19.6 PD and 32.0 PD, in group II, 23.6 PD and 33.5 PD, at distance and near fixation respectively. Postoperatively, in group I, 31 patients (91.2%) showed satisfactory alignment at near and distance fixation. Post-operatively, in group II, 25 patients (80.6%) showed satisfactory alignment at near and distance fixation. Conclusion: Our results suggest both techniques are good options to treat purely tonic esotropias.

Prevalence of Heterophoria in Tibetan Grade-One Students: The Lhasa Childhood Eye Study

Introduction. The study aims to explore the prevalence of heterophoria and associate factors in Tibetan grade-one students. Methods. The Lhasa Childhood Eye Study (LCES) is a school-based cohort study. 1942 grade-one students from 7 elementary schools were randomly sampled by stratified cluster sampling. Ocular examinations were performed in participants, including ocular motility, distance and near visual acuity, cycloplegic autorefraction, and stereoacuity. The near (33 cm) and distance (6 m) fixation cover test was used to differentiate orthophoria, heterophoria, and heterotropia, and the magnitude of the phoria was measured by the Maddox rod and prisma. Results. Of 1856 grade-one students completing all the ocular examinations, 1852 participants finished the ocular alignment test. The mean age was 6.82 ± 0.46 years (range 6∼10 years); 981 (52.97%) were males, and 871 (47.03%) were females. The prevalence of phoria was 22.89% (n = 424). At distance fixation, the prevalence of heterophoria, exophoria, and esophoria was 4.64%, 4.21%, and 0.43% separately, while at near fixation, the prevalence was 22.73%, 22.35%, and 0.38%. No vertical phoria was detected. The mean magnitude of heterophoria at near and distance fixation was −7.63 ± 5.15 PD (exo: −7.83 ± 4.91 PD, eso: +5.67 ± 3.61 PD) and −4.84 ± 5.94 PD (exo: −6.26 ± 4.20 PD, eso: +8.13 ± 3.04 PD). The prevalence of esophoria was associated with hyperopia (OR = 6.38, 95% CI: 1.15–35.28, P = 0.03; OR = 5.42, 95% CI: 1.04–28.24, P = 0.04) and amblyopia (OR = 16.02, 95% CI: 1.81∼141.96, P = 0.01; OR = 11.37, 95% CI: 1.34∼96.52, P = 0.03) at near and distance fixation. The prevalence of exophoria was associated with myopia at near fixation (OR = 2.43, 95% CI: 1.47–4.00, P <0.01). In the near heterophoria group, the proportion of children with abnormal stereoacuity was 23.26% (n = 97), significantly higher (χ2 = 5.70, P = 0.017) than that in orthophoria (17.99%, n = 244). Conclusions. In Lhasa, grade-one pupils have a lower prevalence of heterophoria. Near exophoria was associated with myopia, while esophoria was related to hyperopia and amblyopia both near and distance. Heterophoria may be one of the affected factors for reducing stereoacuity.

Can Clinical Measures of Postoperative Binocular Function Predict the Long-Term Stability of Postoperative Alignment in Intermittent Exotropia?

Purpose. To evaluate whether clinical measures of postoperative binocular functions could predict the long-term stability of postoperative ocular alignment in children with intermittent exotropia. Methods. A retrospective study was performed in thirty-nine children (median: 7 years) who have been surgically treated from intermittent exotropia without overcorrection (less than 10 prism diopters [pd] of exodeviation at 1 month postoperatively). Angles of deviation and binocular functions were measured preoperatively and at 1 month, 6 months, and the final follow-up visit (≥24 months) postoperatively. We examined the relationships between postoperative drift (change of ocular alignment) and binocular functions (sensory fusion, fusional convergence amplitude, and stereoacuity). Results. The surgical success rate (esophoria/tropia ≤5 pd to exophoria/tropia ≤10 pd) dropped to 76.9% at 6 months after surgery and to 53.8% at individuals’ last visit (mean: 37 months). The mean exodrift was 7.7 ± 9.2 pd from the postoperative month 1 to the final visit (p<0.001) on distance fixation. Distance stereoacuity, central fusion, and fusional convergence amplitude significantly improved following surgery (p<0.05). However, no significant correlation was found between their binocular functions measured at the beginning of each follow-up period and the postoperative drift (all p>0.13). Conclusion. Our findings suggest that the clinical measures of sensory fusion, fusional convergence amplitude, and stereoacuity cannot serve as a robust predictor for the long-term stability of postoperative ocular alignment in patients who underwent successful surgery without overcorrection at 1 month postoperatively.

Ambliopia anisometropia

Anisometropic amblyopia is blurred vision due to refractive anomaly without any anatomical disorders of the eyes. It is frequently found among children in their growth and development periods. The prognosis depends on the ambylopia severity, management, patient’s obedience to the management, and age. We report a case of anisometropic amblyopia in a 8-year-old boy with his main complaint was blurred vision of both eyes. The ophthalmological examination showed the visual acuity of both eyes 6/40, PH 6/9. Several tests that showed normal results were as follows: eyeball movements to all directions; pupil responses to light; Hischberg test; cover test dan cover uncover test at near and far distance fixation; alternate cover test; and worth four dots and Maddox rod tests. Cyclopegical refraction with streak retinoscopy at 50 cm distance resulted in right eye S-4.00 C-3.00 x1800 6/9 and left eye S-1.25 C-3.25 x1800 6/7.5; autorefraction of right eye S-4.50 C-3.25 x70 and of left eye S-1.25 C-4.25 x1710. Anterior and posterior segments of both eyes were normal. Conclusion: In this case, the diagnosis was confirmed as anisometropic amblyopia and compound myopic astigmatism of the right and left eyes. The prognosis was dubia ad bonam. The patient was treated with maximal correction glasses and observed for the first four weeks, and then would be evaluated continuously untill the vision was normal. Keywords: amblyopia anisometropia, vision, refraction anomalyAbstrak: Ambliopia anisometropia merupakan gangguan penglihatan akibat kelainan refraksi tanpa disertai adanya kelainan anatomik pada mata yang sering terjadi pada masa perkembangan anak. Prognosis sangat tergantung pada derajat ambliopia, penanganan, kepatuhan pasien terhadap penanganan, dan usia pasien. Kami melaporkan kasus ambliopia anisometropia pada seorang anak berusia 8 tahun, dengan keluhan utama penglihatan kedua mata kabur. Dari pemeriksaan oftalmologik didapatkan visus ODS 6/40, PH 6/9. Beberapa pemeriksaan yang dilakukan memperlihatkan hasil normal, yaitu: pergerakan bola mata ke segala arah; respon pupil terhadap cahaya; Hischberg test; cover test dan cover uncover test pada fiksasi jarak dekat dan jauh; alternate cover test; serta worth four dots test dan Maddox rod test. Pemeriksaan refraksi sikloplegik dengan streak retinoscopy pada jarak 50 cm didapatkan mata kanan S-4,00 C-3,00 x1800 6/9 dan mata kiri S-1,25 C-3,25 x1800 6/7,5 dan pemeriksaan autorefraksi mata kanan S-4,50 C-3,25 x70 dan mata kiri S-1,25 C-4,25 x1710. Pemeriksaan segmen anterior dan posterior mata kanan dan kiri dalam batas normal. Simpulan: Diagnosis pada kasus ini ialah ambliopia anisometropia ODS dan astigmatisma miopikus kompositus ODS, dengan prognosis dubia ad bonam. Terapi yang diberikan ialah kacamata koreksi maksimal dan diobservasi selama 4 minggu pertama, dan akan dievaluasi terus sampai ketajaman penglihatan normaL. Kata kunci: ambliopia anisometropia, ketajaman penglihatan, kelainan refraksi

Convergence Insufficiency/Divergence Insufficiency Convergence Excess/Divergence Excess: Some Facts and Fictions

Great discrepancies are often encountered between the distance fixation and the near-fixation esodeviations and exodeviations. They are all attributed to either anomalies of the AC/A ratio or anomalies of the fusional convergence or divergence amplitudes. We report a case with pseudoconvergence insufficiency and another one with pseudoaccommodative convergence excess. In both cases, conv./div. excess and insufficiency were erroneously attributed to anomalies of the AC/A ratio or to anomalies of the fusional amplitudes. Our purpose is to show that numerous factors, other than anomalies in the AC/A ratio or anomalies in the fusional conv. or divergence amplitudes, can contaminate either the distance or the near deviations. This results in significant discrepancies between the distance and the near deviations despite a normal AC/A ratio and normal fusional amplitudes, leading to erroneous diagnoses and inappropriate treatment models.