LETTERS TO THE EDITOR
|Year : 2022 | Volume
| Issue : 6 | Page : 1192-1194
Visual morbidity in stroke survivors: A pilot study
Arya R Nedumgattil1, Sanitha Satyan1, Madhukar Mohan2, Jomal Mathew2, Ashok Menon2
1 Department of Ophthalmology, Little Flower Hospital and Research Center, Angamaly, Kerala, India
2 Department of Neurology, Little Flower Hospital and Research Center, Angamaly, Kerala, India
|Date of Submission||16-May-2022|
|Date of Decision||11-Jul-2022|
|Date of Acceptance||30-Jul-2022|
|Date of Web Publication||04-Nov-2022|
Department of Neurology, Little Flower Hospital and Research Center, Angamaly - 683 572, Kerala
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Nedumgattil AR, Satyan S, Mohan M, Mathew J, Menon A. Visual morbidity in stroke survivors: A pilot study. Ann Indian Acad Neurol 2022;25:1192-4
With a documented cumulative incidence of 105-152/100,000 annually, and a crude prevalence of 44.29-559/100,000 during the past decade, stroke remains a major cause of chronic adult disability in our country. In Kerala, stroke prevalence was found to be 300/100,000 in a survey of noncommunicable diseases covering 84,456 adults. Stroke assessment and rehabilitation conventionally focuses on motor function but disability may also lie in the domains of sensory perception, communication, executive function, or memory. A large proportion of the brain being devoted to visual processing and visually guided tasks, stroke frequently results in visual abnormalities., Visual impairment worsens functionality and hinders rehabilitation. Stroke-afflicted patients may also have pre-existing unattended ophthalmic conditions like suboptimally corrected refractive errors, cataract, undetected glaucoma, diabetic and hypertensive retinopathy, or age-related macular degeneration (ARMD) that can compound stroke-related visual morbidity and risk of falls. Addressing correctable problems such as refractive errors and vision-impairing cataracts can hugely improve quality of life. However, guidelines recommending routine ophthalmological or optometric evaluation in stroke survivors are ignored in resource-stressed healthcare systems because they are time-consuming and patient-perceived success is often negligible. This prospective hospital-based observational pilot study aimed to address the lacuna in Indian literature pertaining to the visual burden inpatients with ischemic stroke.
In accordance with Helsinki guidelines, following clearance by the Institutional Ethical Committee, adult patients hospitalized with a first ischemic arterial stroke were recruited after obtaining informed consent; those with language or cognitive disturbances or impairment of sensorium precluding ophthalmologic assessment were excluded. Ophthalmic evaluation was carried out prior to discharge. Clinical details, prior ocular and comorbid history, and brain imaging findings were recorded. Visual acuity at distant and near fixation was checked and refraction performed. Visual field, latent strabismus with cover test, color vision, extraocular movements, gaze, convergence, and visual neglect were assessed.
The study population consisted of 52 patients, 36 males, and 16 females, aged 37–88 years with ischemic stroke involving the basal ganglia (six patients), thalamus (10), and pons (5). Large artery involvement in the middle cerebral and posterior cerebral artery territories was seen in 18 and 13 patients, respectively. The mean period of ophthalmic evaluation, carried out by a single optometrist and ophthalmologist, was 7 days, post-onset of stroke. The results have been compiled in [Table 1] and [Table 2]. Field defects were detected in 8 of 44 patients in whom reliable, reproducible perimetry results could be obtained; six had hemianopia while two had peripheral constriction. Forty-seven patients (90.3%) had visual impairment due to refractive error; in 10, visual acuity did not improve even after correction. Ocular pathology was noted in 41 patients.
In the United Kingdom “Impact of Visual Impairment after Stroke” (IVIS) study, visual abnormalities were found in 752 of 1033 assessable patients with acute stroke making up 58% of stroke admissions. A similarly high incidence of visual morbidity was found in our small cohort of 52 patients. Over 70% were found to have correctable refractive errors and potentially treatable ophthalmological conditions, particularly cataract. Visual impairment benefitting from refractive correction alone was reported in 14% of stroke patients from Northern Ireland. Not all cataracts cause visual impairment; although undetected cataract was common in a poststroke study from Hongkong only 14.2% resulted in significant visual loss. Uncorrected refractive errors and undetected ocular conditions would be commoner in developing countries where routine optometric check-ups are rare and ophthalmologists are consulted only when reading or vision is significantly impaired. Stroke patients from Nepal had ocular comorbidities such as cataract (10%), refractive error (27.5%), ARMD (10%), diabetic retinopathy (7.5%), hypertensive retinopathy (12.5%), and optic atrophy (2.5%). In IVIS, 420/752 patients had ocular problems that predated or aggravated the vision impairment caused by stroke.
Where visual abnormalities resulting from stroke are concerned, informative data can be derived from two large multicenter studies from England., In IVIS, where assessment was carried out a median of 4 days poststroke, new visual abnormalities were found in 616/1033 (59.6%). The earlier, “vision in stroke” (VIS) study, recruited patients referred for detailed evaluation at a median of 22 days poststroke. Of 915 referrals, 37.5% had reduced central visual acuity and 52% had peripheral field loss, most commonly homonymous hemianopia. Acquired strabismus was noted in 16% and ocular motility disorders in 68%. Fifteen percent had visual inattention and 4.6% had other visual perceptual disorders. The prevalence of visual field loss in our cohort (18%) was comparable to other centers., Nevertheless, the true incidence of immediate poststroke hemianopia may have been underestimated as patients excluded due to disturbances of language and cognition are likely to have also had hemianopia; moreover 10% of patients with poststroke homonymous hemianopia may recover their field within the first 10 days. Imaging correlated with the field defects in most cases but hemianopia also occurred in patients with apparently isolated ganglionic and thalamic infarcts, possibly due to involvement of lateral geniculate body or the geniculo-calcarine tract. Partial hemianopia may improve over 10–12 weeks aided by cortical reorganization and adaptive strategies, which could be enhanced by dedicated rehabilitative measures. Tools to overcome persistent hemianopia include prism glasses, scrolling text and typoscopes to aid reading but not all interventions have a robust evidence base. Visuospatial neglect was detected in 13.6% of patients. Inattention and other perceptual disorders are more common in the acute stages. Neglect may occur with or without hemianopia and is more frequent with right hemispheric lesions. Mirror therapy may be a useful rehabilitation technique. Convergence insufficiency, although tabulated with ocular comorbidities [Table 2], may also result from stroke but compared to IVIS, the prevalence of visual field defect, strabismus and ocular motility defects was lower.
Significant disparity exists in visual assessment and care even in healthcare systems with advanced stroke services. Existing screening methods lack sensitivity due to dependence on symptoms reported by the patient or caregiver. Rowe et al. recommend a standardized format for vision screening and assessment as well as a 15-item questionnaire for assessing quality of life poststroke. Despite its limitations and small sample size, the results confirm that there is significant visual morbidity among stroke survivors, much of it potentially correctable in the form of refractive errors and cataract. An optometrist and ophthalmologist should be integral members of the stroke rehabilitation team with early visual assessment and correction being among the goals concurrent with motor and cognitive rehabilitation.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]