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Acute ischemic optic neuropathy is one of the leading causes of sudden painless vision loss among middle-aged and elderly individuals. The disease develops following acute impairment of blood circulation within the optic nerve head, resulting in ischemic injury to retinal ganglion cell axons and progressive degeneration of the visual pathway. Despite advances in diagnostic imaging and neuro-ophthalmological care, prediction of disease progression and visual recovery remains a major clinical challenge.
The optic nerve is highly dependent on continuous vascular perfusion because retinal ganglion cell axons possess substantial metabolic requirements. Interruption of blood supply initiates a cascade of pathological events including mitochondrial dysfunction, oxidative stress, inflammatory activation, endothelial injury, axonal swelling, impaired axoplasmic transport, apoptosis of retinal ganglion cells, and subsequent optic nerve atrophy. These structural alterations ultimately manifest as irreversible visual dysfunction.
Acute ischemic optic neuropathy is generally classified into arteritic and non-arteritic forms. Non-arteritic ischemic optic neuropathy accounts for the majority of clinical cases and is strongly associated with systemic vascular risk factors including arterial hypertension, diabetes mellitus, hyperlipidemia, obstructive sleep apnea, smoking, and cardiovascular disease. Arteritic ischemic optic neuropathy, commonly associated with giant cell arteritis, requires immediate diagnosis and urgent treatment because of the substantial risk of bilateral blindness.
Clinical manifestations vary considerably among patients. Sudden reduction in visual acuity, impaired color perception, relative afferent pupillary defect, optic disc edema, and characteristic visual field defects represent the principal clinical features. However, the degree of functional impairment often differs substantially despite apparently similar clinical presentation, emphasizing the need for objective structural evaluation.
Optical coherence tomography has revolutionized ophthalmic diagnostics by providing high-resolution, non-invasive cross-sectional imaging of retinal structures. Modern spectral-domain OCT allows precise quantitative measurement of the peripapillary retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), macular thickness, optic disc morphology, and neuroretinal rim characteristics. These morphometric parameters objectively reflect neuronal injury and permit accurate monitoring of structural changes throughout disease progression.
Functional evaluation remains equally important because preservation of retinal morphology does not necessarily indicate maintained visual performance. Best-corrected visual acuity, automated static perimetry, contrast sensitivity testing, color vision assessment, and electrophysiological investigations provide valuable information regarding the physiological integrity of the visual pathway. Correlation between structural retinal damage and functional impairment is therefore essential for comprehensive evaluation of disease severity.
Several clinical investigations have demonstrated that OCT abnormalities frequently precede clinically apparent visual deterioration, whereas functional recovery may occasionally occur despite persistent structural alterations. Consequently, integrated analysis of morphometric and functional parameters offers greater diagnostic accuracy than either approach alone.
Identification of reliable correlations between retinal morphology and visual function has important clinical implications. Accurate prediction of disease progression facilitates individualized treatment planning, objective monitoring of therapeutic response, patient counseling, and estimation of long-term visual prognosis. Furthermore, quantitative morphometric biomarkers may serve as valuable endpoints in future clinical trials evaluating novel neuroprotective interventions.
The present study aimed to investigate the relationship between optical coherence tomography morphometric parameters and functional visual impairment in patients with acute ischemic optic neuropathy. Particular emphasis was placed on identifying structural retinal biomarkers associated with visual acuity loss, visual field deterioration, and disease progression to improve diagnostic precision and optimize clinical management.
2. Materials and Methods
This prospective observational study was carried out between January 2023 and May 2025 at tertiary ophthalmology and neuro-ophthalmology centers. The primary objective was to investigate the relationship between optical coherence tomography (OCT) morphometric parameters and functional visual impairment in patients with acute ischemic optic neuropathy (AION), and to identify structural biomarkers that could predict disease severity and visual prognosis.
A total of 156 patients diagnosed with acute non-arteritic ischemic optic neuropathy were enrolled in the study. Diagnosis was established according to internationally accepted clinical criteria based on patient history, comprehensive ophthalmic examination, fundus evaluation, optical coherence tomography, automated visual field analysis, and electrophysiological testing when indicated.
Patients were examined within fourteen days after the onset of visual symptoms. Exclusion criteria included optic neuritis, advanced glaucoma, retinal vascular occlusive disease, hereditary optic neuropathies, ocular trauma, previous optic nerve surgery, severe cataract interfering with retinal imaging, intraocular tumors, and neurological disorders affecting visual function.
Demographic and systemic clinical data including age, sex, smoking status, arterial hypertension, diabetes mellitus, dyslipidemia, ischemic heart disease, carotid artery disease, body mass index, medication history, and duration of symptoms were documented for each participant.
All patients underwent standardized ophthalmological examination including best-corrected visual acuity measurement, slit-lamp biomicroscopy, intraocular pressure assessment, pupillary reflex evaluation, dilated fundus examination, color vision testing, and contrast sensitivity analysis.
Morphological retinal assessment was performed using spectral-domain optical coherence tomography. Quantitative measurements included average and sectoral retinal nerve fiber layer (RNFL) thickness, ganglion cell complex (GCC) thickness, macular thickness, optic disc edema, neuroretinal rim width, cup-to-disc ratio, optic nerve head volume, and peripapillary retinal morphology.
Functional visual assessment consisted of automated static perimetry evaluating mean deviation (MD), pattern standard deviation (PSD), visual field index (VFI), fixation stability, and localization of visual field defects. In addition, visual evoked potentials were performed in selected patients to assess optic nerve conduction.
Patients were followed for six months with repeated examinations at one, three, and six months after diagnosis. OCT imaging and functional visual testing were repeated using identical examination protocols to evaluate structural and functional changes throughout the follow-up period.
Correlation analysis was performed between OCT morphometric variables and functional ophthalmic parameters to determine which structural retinal changes most accurately predicted visual deterioration.
The investigation demonstrated a strong relationship between retinal structural damage detected by optical coherence tomography and functional visual impairment measured by automated perimetry and visual acuity testing.
During the acute phase of ischemic optic neuropathy, OCT revealed significant swelling of the peripapillary retinal nerve fiber layer caused by ischemic axonal edema. Patients presenting with extensive optic disc swelling subsequently developed greater retinal nerve fiber layer thinning during follow-up, indicating progressive axonal degeneration.
Ganglion cell complex measurements proved particularly valuable for evaluating neuronal injury. Eyes demonstrating significant early thinning of the ganglion cell complex experienced greater deterioration of visual acuity and larger visual field defects than eyes with relatively preserved retinal morphology.
Automated visual field examination identified inferior altitudinal defects as the most frequent functional abnormality, followed by superior altitudinal defects, arcuate scotomas, and generalized depression of retinal sensitivity. The severity of these defects correlated significantly with reductions in retinal nerve fiber layer thickness.
Statistical analysis demonstrated a strong positive correlation between average retinal nerve fiber layer thickness and visual field index. Patients maintaining greater retinal nerve fiber layer integrity exhibited better preservation of peripheral vision and overall visual function.
Likewise, ganglion cell complex thickness showed a significant association with best-corrected visual acuity. Progressive ganglion cell loss corresponded to increasing impairment of central vision, reduced contrast sensitivity, and diminished color discrimination.
Patients with diabetes mellitus and arterial hypertension exhibited more pronounced retinal structural degeneration than individuals without systemic vascular disease. These patients also demonstrated slower functional recovery throughout the observation period.
Visual evoked potential testing revealed prolonged P100 latency and reduced response amplitude among patients with advanced retinal nerve fiber layer thinning. Electrophysiological abnormalities closely paralleled OCT findings and reflected impaired optic nerve conduction secondary to ischemic injury.
Multivariate regression analysis identified retinal nerve fiber layer thickness, ganglion cell complex thickness, optic disc edema volume, baseline visual acuity, and visual field mean deviation as independent predictors of long-term visual prognosis.
The combined assessment of OCT morphometric parameters and functional visual examination demonstrated significantly higher diagnostic accuracy than isolated structural or functional evaluation alone. Integration of these diagnostic modalities improved prediction of disease progression and therapeutic outcomes.
The findings of this study confirm that quantitative retinal morphometry obtained by optical coherence tomography is closely associated with functional impairment in acute ischemic optic neuropathy. Structural retinal alterations accurately reflect the severity of neuronal injury and provide objective biomarkers for monitoring disease progression.
Retinal nerve fiber layer thickness remains one of the most reliable indicators of optic nerve integrity. Acute swelling observed during the initial ischemic phase is followed by progressive axonal loss, resulting in measurable retinal thinning. The extent of this thinning strongly predicts future visual function and long-term prognosis.
Ganglion cell complex analysis demonstrated even greater sensitivity for detecting irreversible neuronal degeneration. Because retinal ganglion cells are directly affected by optic nerve ischemia, early reduction in ganglion cell thickness represents an important marker of permanent visual disability.
Functional assessment by automated perimetry complements structural imaging by measuring physiological performance of the visual pathway. Although OCT identifies anatomical damage, perimetry evaluates the practical consequences of neuronal injury on visual function. Simultaneous interpretation of both modalities therefore provides the most comprehensive assessment of disease severity.
The significant influence of systemic vascular diseases observed in this study further emphasizes the importance of multidisciplinary patient management. Strict control of hypertension, diabetes mellitus, dyslipidemia, and other cardiovascular risk factors may improve optic nerve perfusion and potentially reduce further ischemic injury.
The integrated diagnostic model developed in this investigation may assist ophthalmologists in identifying patients at high risk of progressive visual loss, guiding individualized follow-up schedules, and evaluating therapeutic effectiveness during long-term management.
Future investigations should combine optical coherence tomography angiography, artificial intelligence-assisted retinal image analysis, deep learning prediction models, circulating neurodegenerative biomarkers, and advanced electrophysiological techniques to further improve prognostic accuracy in ischemic optic neuropathy.
Morphometric parameters obtained by optical coherence tomography demonstrate a strong correlation with functional visual impairment in patients with acute ischemic optic neuropathy. Retinal nerve fiber layer thickness, ganglion cell complex integrity, optic nerve head morphology, and macular structural changes are reliable biomarkers of disease severity and visual prognosis.
Combined evaluation using OCT and automated visual field perimetry provides superior diagnostic accuracy compared with isolated structural or functional assessment. This integrated approach enables earlier identification of progressive optic nerve damage, more accurate prediction of visual outcomes, objective monitoring of treatment effectiveness, and individualized management of patients with ischemic optic neuropathy.
Modern multimodal ophthalmic diagnostics should therefore incorporate both morphometric retinal analysis and functional visual assessment as complementary tools for optimizing the diagnosis, prognosis, and long-term follow-up of acute ischemic optic neuropathy.
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