Accommodative esotropia: An outcome analysis from a tertiary center in Oman :OK Sreelatha, Hajar Ali Al-Marshoudi, Maha Mameesh, Sana Al Zuhaibi, Anuradha Ganesh, Oman Journal of Ophthalmology

ORIGINAL ARTICLE
Year : 2022 | Volume : 15 | Issue : 3 | Page : 274--278

Accommodative esotropia: An outcome analysis from a tertiary center in Oman

OK Sreelatha¹, Hajar Ali Al-Marshoudi², Maha Mameesh³, Sana Al Zuhaibi³, Anuradha Ganesh³,
¹ Department of Ophthalmology, Directorate of Health Services, Thiruvananthapuram, Kerala, India
² Department of Ophthalmology, College of Medicine and Health Sciences, Sultan Qaboos University, Seeb, Oman
³ Department of Ophthalmology, Sultan Qaboos University Hospital, Seeb, Oman

Correspondence Address:
O K Sreelatha
CHC, Kalakkode, Kollam, Kerala
India

Abstract

AIM: The aim of this study is to determine the outcome of accommodative esotropia (ET) and influencing factors in young Omani children. SUBJECTS AND METHODS: In this retrospective cohort, children diagnosed with accommodative ET who had followed up in a tertiary hospital from 2006 to 2011 were identified. Parameters studied included cycloplegic refraction and its change with time, ocular alignment, binocularity, visual acuity (VA), amblyopia, and requirement for surgery. RESULTS: A total of 51 patients were identified. Twenty-four patients were diagnosed with fully accommodative ET (FAET) and 27 with partially accommodative ET (PAET). The mean (± standard deviation [SD]) age of onset and reporting were 2.6 (±1.58) and 3.2 (±1.84) years in the two groups, respectively. The mean (SD) cycloplegic refraction at presentation was 4.50 (±1.66) in the FAET group and 3.65 (±1.67) in the PAET group. Anisometropia was present in 28% of patients. The mean follow-up period was 4.9 years. The following were detected in the final visit. A reduction in amblyopia from 43% to 6% of patients, binocularity in 75% of patients, and a mean increase of 0.64 (±1.3) D in cycloplegic refraction from the first visit (P = 0.005). The mean angle of deviation at near and distance was 29.86 (±15.21) and 17.80 (±10.14) prism diopters, respectively, in FAET patients and 30.15 (±14.83) and 29.53 (±15.53), respectively, in PAET patients. Thirty-seven percent of the PAET patients underwent surgery within 5 years from diagnosis. All participants in this cohort continued to wear glasses in the last follow-up visit. CONCLUSION: Most children with refractive accommodative ET have an excellent outcome in terms of VA and binocular vision. The PAET group was characterized by delayed reporting, the presence of anisometropia, and lower hypermetropia. Further study is required to determine the possibility of weaning glasses in FAET patients.

How to cite this article:
Sreelatha O K, Al-Marshoudi HA, Mameesh M, Al Zuhaibi S, Ganesh A. Accommodative esotropia: An outcome analysis from a tertiary center in Oman.Oman J Ophthalmol 2022;15:274-278

How to cite this URL:
Sreelatha O K, Al-Marshoudi HA, Mameesh M, Al Zuhaibi S, Ganesh A. Accommodative esotropia: An outcome analysis from a tertiary center in Oman. Oman J Ophthalmol [serial online] 2022 [cited 2023 Mar 28 ];15:274-278
Available from: https://www.ojoonline.org/text.asp?2022/15/3/274/360426

Full Text

Introduction

Accommodative esotropia (ET) is the most common form of childhood ET.[1],[2] The prevalence of accommodative ET has been estimated to be 1%–2% in the Western population.[2],[3] The convergent misalignment of visual axes has been attributed to hyperopia associated with an abnormal fusional divergence.[4],[5],[6] Accommodative ET initially presents as intermittent esodeviation between 1½ and 4 years of age.[3],[5],[6] It has a favorable prognosis if appropriate treatment is initiated early.[7],[8] Optical correction of hypermetropia is usually successful in reestablishing ocular alignment. There has always been a concern regarding striking a balance between achieving bifoveal fixation and avoiding interference with emmetropization by prescribing full hypermetropic refractive correction when treating accommodative ET in young children. The management of accommodative ET includes (1) identifying risk factors for the development of accommodative ET, (2) providing optimal refractive correction without interfering with the process of emmetropization, and (3) weaning of glasses when possible[9],[10],[11],[12] The current study aims to describe the clinical characteristics and outcome in Omani children with accommodative ET. To our knowledge, no similar study has been conducted in Oman.

Subjects and Methods

The medical records of all Omani children diagnosed with accommodative ET who attended the pediatric ophthalmology service in a tertiary referral hospital from January 1 to May 30, 2011, were reviewed retrospectively.

Study sample

Omani children aged 0–6 years at presentation, or who presented within 1 year of treatment started elsewhere, with a hypermetropia (spherical equivalent) >1.50 D, who showed significant reduction (>10 prism diopter [PD]) of ET with hypermetropic correction, and a minimum follow-up of 3 years was included in the study. Patients who had intraocular surgeries, any ocular condition that may affect visual acuity (VA) or refraction, including corneal irregularities, cataracts, retinal dystrophy, etc., and children with developmental delays were excluded from the study.

All the patients underwent a standard ophthalmology evaluation. Age-appropriate tests were used to measure VA. The angle of ET was measured for near and distance using prisms. Follow-up angle measurements were done with the given spectacle correction. Accommodative Convergence/Accommodation (AC/A) ratio was calculated using the heterophoria method, and a value above five was considered high. When possible, stereo acuity was measured using stereo acuity tests (Titmus stereo and Lang tests). The level of stereo acuity was not considered in this study. Measurable level of stereo acuity “present” or “absent” taken as the criteria. Bagolini striated lens test was performed in cooperative children in whom stereo tests could not be done or were reported negative. Cycloplegic refraction using atropine eye drops was done for all participants at regular intervals. A full hypermetropic correction was advised for all children. Bifocal glasses were prescribed for patients with high AC/A.

Amblyopia treatment was initiated in the presence of interocular VA difference of over two Snellen lines or when the child showed a fixation preference for one eye. Compliance with the use of glasses and occlusion therapy was assessed in every visit as good (90%–100% usage), fair (70%–85% usage), or poor (<60% usage).

Study patients were grouped into (1) Fully accommodative ET (FAET; ≤10 PD of deviation after wearing full hypermetropic spectacle correction for 8 weeks) and (2) Partially accommodative ET (PAET; >10 PD of residual ET even after wearing full hypermetropic spectacle correction for 8 weeks).

The study was approved by the institutional ethical committee.

Results

A total of 70 patients were identified with accommodative ET. Fifty-one (29 female and 22 male) patients met the inclusion criteria and were included in the analysis. The mean follow-up period was 4.9 years (range 3.1–5 years). Forty-five (88%) patients had 5 years of follow-up. Twenty-seven (47%) had FAET. High AC/A was found in 12 (24%) patients. The mean (standard deviation [SD]) age of onset was 2.6 (±1.58) years (range 3 months–6 years). The age of onset was >2 years in 29 (57%) patients. The mean (SD) reporting age was 3.2 (±1.84) years.

[Table 1] describes the clinical features of patients with FAET and PAET.{Table 1}

Angle of deviation

The mean (±SD) angle of deviation at the first visit was 30 (±15) PD at near fixation and 24 (±14) PD at distance fixation. The mean (±SD) angle of deviation after 5 years of follow-up was 8.5 (±8) PD at near fixation and 6 (±7) PD at distance fixation [Table 2]. After 5 years of treatment, for FAET, the mean (±SD) was 4.6 (±4.22) and 2.85 (±3.77) at near and distance, respectively. For PAET, 12.58 (±8.84) and 10.21 (±8.46) at near and distance, respectively. Thirty-seven percent (10 out of 27) of the PAET had strabismus surgery within the first 5 years of treatment.{Table 2}

Visual acuity and amblyopia

Reduction in VA at least in one eye at first visit was seen in 44% of patients. VA of <6/9 at the end of 5 years of treatment was seen in 7.8% of patients. Amblyopia was present in 6% of patients at the end of the 5-year follow-up compared to 43% of patients at presentation.

Hypermetropia and anisometropia

Mean (SD) hypermetropia was 4.1 (±1.7) D. Anisohypermetropia was noted in 28% of patients; 71% had amblyopia. Cycloplegic refraction showed an increase (0.64 D ± 1.3D) in hypermetropia in the initial 5 years (P = 0.005). The distribution of hypermetropia at first visit in different age groups is described in [Table 3].{Table 3}

Binocularity

Thirty-eight (75%) patients had binocularity at the end of 5 years of treatment. Of them, 28 had measurable stereo acuity, and 10 had a positive Bagolini striated lens test.

Compliance to glasses and amblyopia therapy

Good compliance to glasses was present in 48 (94%) patients. Fair to good compliance to patching was reported in 23 (89%) out of 26 patients.

Discussion

The usual age of onset of accommodative ET is 2–4 years.[1] The youngest patient in our cohort was 3 months of age. Younger age of onset (below 6 months) has been reported in 8%–27% of patients in previous studies.[13],[14] Children with FAET were found to be older than those with PAET in our study, and the same has been reported in other studies.[7] In our cohort, the PAET group had a mean period of 10 months of delayed reporting compared to the FAET group. Delayed initiation or partial compliance with an optical correction may contribute to PAET development.[8] Previous studies have also reported that PAET may develop due to uncorrected hyperopia or nonaccommodative factors such as congenital fusion dysfunction and rectus muscle dysfunction due to the absence of an effective treatment in FAET patients.[15]

More than one-third of patients had amblyopia at the initial visit. Amblyopia was more prevalent (nearly 75%) among anisometropes. Mulvihill et al.[8] reported a similar finding about amblyopia among anisometropes. Anisometropia appears to increase the risk of accommodative ET development, even though the hypermetropia may be low. This is particularly seen in the presence of amblyopia.[6],[7],[16] Similar to other studies, we report a good visual outcome in our cohort. Good outcomes appear to be linked to compliance with glasses and amblyopia therapy. Amblyopia reduced from 40% to 6% after the treatment.

Patients with FAET demonstrate better stereopsis compared to those with PAET.[7] Good stereopsis is achievable when esodeviation is ≤4 PD at distance and ≤5 PD at near fixation.[17],[18] Patients with FAET have a lesser disruption in binocularity. Further, achieving near orthophoria with appropriate spectacle correction reduces the incidence of amblyopia in patients with FAET compared to patients with PAET. More than half of the patients with PAET had impaired binocularity despite optimum hypermetropic correction. A delayed presentation with consequent delay in initiation of spectacle correction in patients with PAET results in a residual angle of esodeviation precluding binocular single vision. Earlier onset (≤2 years of age) of the deviation seen in patients with PAET may be the reason for reduced stereo acuity in this group. Wilson et al.[18] reported that in accommodative ET, a constant ET for over 4 months and the development of monofixation syndrome led to reduced stereo acuity.[19]

Similar to other studies,[7],[8] patients with FAET in the study cohort were found to have higher hypermetropia than those with PAET. A slight increase (mean 0.50D) in hypermetropia was noted over 5 years. Other studies, too, have described this trend.[10],[20],[21] Mulvihill reported stable hypermetropia in patients with accommodative ET over a mean follow-up of 4.5 years.[8] A study with a longer follow-up of 10 years reported an average decline of hypermetropia 0.1D per year in patients with accommodative ET.[7],[22] Decrease in hypermetropia on longer follow-up may be attributed to emmetropization.[10] Typically, normal children undergo a rapid decrease in hypermetropia between 3 and 9 months of age, followed by a long period of near-emmetropia from 1 to 5 years of age. Children with accommodative ET show little change and at times, a slight increase in hypermetropia up to 7 years of age, followed by a decrease in hypermetropia after 7 years of age.[21]

Patients with FAET demonstrate better control of ET when given full hypermetropic correction than when undercorrected even by as little as one diopter.[23] This has led to the practice of providing maximum hypermetropic correction for accommodative ET. All our patients received full hypermetropic correction, and none had discontinued the hypermetropic correction throughout the study period. Biler reported that partial or full optical correction of hyperopia had a similar effect on refractive development of the eye in children with accommodative ET.[11] The treatment of accommodative ET in children older than the age of 5 years did not appear to affect refractive development.

Previous studies have reported that patients with accommodative ET retain their hypermetropic correction even in adulthood.[24] However, Mohney et al.[7] reported a spectacle discontinuing rate of 8%, 20%, and 37% by 5, 10, and 20 years, respectively, after diagnosis in their cohort. Gradual weaning children out of spectacles has been advocated as it may increase the proportion of patients who can discontinue spectacle wear, even at an earlier age.[12] Esodeviation without correction and its decline may be a clinical indicator for reducing hyperopic correction.[25] Adequate accommodative ability seems to be a prerequisite for establishing optimal hyperopic undercorrection. It is not appropriate to consider a reduction in hyperopic correction in the presence of reduced bilateral accommodative amplitude. The development of myopia and degradation of ocular alignment may be indicators of early emmetropization in patients with FAET.[9]

Although the angles of deviation at near fixation were similar in both FAET and PAET groups, the initial angle at distance fixation was smaller in the FAET group than in the PAET group. Other studies have reported smaller angles in patients with FAET.[7] A total of 37% of the patients with PAET in our cohort underwent strabismus surgery within the first 5 years of diagnosis. Mohney et al.[7] reported that 13.5% and 75.8% of patients with FAET and PAET, respectively, required strabismus surgery during 10 years of follow-up. Patients with FAET may decompensate over time.[26] None of the patients with FAET in our cohort showed decompensation within the first 5 years of diagnosis. However, a longer follow-up and larger sample are required to assess the long-term outcome.

Conclusion

The current study demonstrates a favorable outcome of treatment in refractive accommodative ET. Early onset of the disease and delayed presentation are likely to have a negative effect on binocularity and VA. All the patients in our study continued to require full hypermetropic correction. The presence of anisometropia, early onset, delayed treatment, and lower levels of hypermetropia may suggest a greater predilection for developing PAET. Future studies with longer follow-up may address the possibility of weaning of hypermetropic correction in patients with FAET.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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