Medically unexplained visual loss in adult patients

PURPOSE: To evaluate the characteristics of patients with nonorganic or medically unexplained visual loss (MUVL) presenting to a neuro-ophthalmology clinic. METHODS: A retrospective review of the case notes of patients identified from our diagnostic register. All patients had been followed up for at least 18 months and investigations (including, in all cases, neuroimaging) had failed to reveal any underlying pathology. To be included, patients had to have at least one inconsistent feature on visual function testing. RESULTS:: We identified 58 patients with MUVL. A total of 79% of patients were female and 21% were male. In total, 36% of patients had been seen in other medical specialties with unexplained symptoms. In all, 60% of patients complained of glare or pain. Of the patients with bilateral visual loss, the acuities were frequently the same in each eye and the most common pattern of visual field loss was concentric contraction. Those with unilateral visual loss had a more variable pattern of visual failure. In total, 22% of patients showed some visual recovery though this was usually incomplete. In one patient, organic pathology accounting for the visual symptoms became apparent after the end of the 18 month follow-up period. CONCLUSIONS: Medically unexplained symptoms, in general, form an important part of the workload in most medical specialties. Unexplained symptoms in ophthalmology have not been well studied. Terminology should be brought into line with that used in other medical specialties. Further work may help in the identification of positive diagnostic features of MUVL which should not be simply a 'diagnosis of exclusion'.     

Idiopathic photoreceptor dysfunction causes unexplained visual acuity loss in later adulthood

Progressive visual loss, caused by initially unrecognized retinal photoreceptor dysfunction predominantly affecting cones, developed in six patients in late adulthood. Because of minimal ophthalmoscopic retinal abnormalities, the patients initially had been suspected of having optic neuropathy or psychogenic visual loss. The correct diagnosis was ultimately established by finding electroretinographic abnormalities and color discrimination losses out of proportion to visual acuity loss. In no case was a causative agent or a family history of photoreceptor disease identified. In many other respects, however, features of the patients' illness resemble those described previously under the headings of cone dysfunction syndrome, cone dystrophy, cone degeneration, and cone-rod dystrophy.     

The incidence of unexplained visual loss following removal of silicone oil

Purpose

To assess the incidence and clinical features of unexpected visual loss after removal of silicone oil (ROSO).

Patients and methods

A retrospective cross-sectional observational study of 421 consecutive eyes, which underwent silicone oil removal at one institution over a 2-year period.

Results

Fourteen (3.3%) patients, (12 male, mean age of 53.1 years) suffered unexplained visual loss. In these eyes, the mean duration of silicone oil fill was 141 days (range 76–218). The mean loss of visual acuity was 3.7 (range 2–6) Snellen lines (SL) at 1 month, 3.5 (2–6) SL at 3 months and 2.91 (0–6) SL at 6 months. The change from preoperative visual acuity was statistically significant at all visits (P=0.02). Subgroup analysis of 20 fovea-sparing giant retinal tear (GRT) detachments, observed 10 (50%) cases of visual loss after ROSO. Electrodiagnostic testing suggested predominantly macular dysfunction, with optic nerve involvement in one case. Five of the 14 cases had variable recovery of vision.

Conclusion

There is a 3.3% overall incidence of visual loss following ROSO with a high rate (50%) observed in maculae on GRT detachments. Although recovery of visual acuity is seen in a minority of cases, visual loss after ROSO remains a serious and unexplained concern for vitreoretinal surgeons.     

Paracentral acute middle maculopathy as a cause of unexplained visual loss in central retinal vein occlusion

A 79-year-old man presented with unilateral unexplained sudden onset visual loss in the setting of central retinal vein occlusion (CRVO). Non ischemic CRVO in the right eye (RE) was confirmed on fluorescein angiography. Spectral domain optical coherence tomography (SD-OCT) showed absence of macular edema and hyperreflective band-like lesions in the middle retinal layers of the RE suggesting a diagnosis of paracentral acute middle maculopathy (PAMM). Patient was observed and after 3 months, best-corrected visual acuity in the RE spontaneously improved from 38 to 56 ETDRS letters. SD-OCT scans showed thinning of the inner nuclear layer of the RE. OCT angiography in the RE revealed a mild attenuation of the vascular flow signal in the superficial capillary plexus and patchy areas of vascular flow void in the deep capillary plexus, as compared to the fellow eye.The present case outlines the importance of recognising PAMM as a cause of unexplained visual loss. In the setting of a CRVO with sudden vision loss and absence of macular edema, clinicians should pay attention to any hyperreflectivity and/or to thinning of the middle retinal layers on SD-OCT.     

Functional visual loss

Patients with functional loss of visual acuity or visual fields range from the "deliberate malingerer" to the "suggestible innocent." Between these extremes are patients with varying mixtures of fraud and suggestibility. These patients do not, as a rule, have psychiatric disease and do not need to see a psychiatrist. The ophthalmologist must be able to control frustration with these patients to prove that the patient has better visual fields and visual acuity than admitted to, and so that he can perform a careful, dispassionate examination to establish that no organic disease is present. This examination makes it possible to offer believable reassurance to the patient. Simple reassurance seems to be effective therapy.     

Functional visual loss

Functional visual loss is a common problem encountered in practice. It must be recognized that this problem occurs in patients who have organic illness. Manual perimetry is the most effective method for evaluating functional visual loss, and the presence of a central scotoma in a functional visual field strongly suggests that organic pathology is present.Neuropsychological and psychiatric intervention can be useful in treating these patients.     

Unexplained visual loss

Dominant optic atrophy is the most common heredodegenerative optic neuropathy. Typically, patients present with slowly progressive, bilaterally decreased central visual acuity. Subtle central or cecocentral visual field defect and normal peripheral isopters are demonstrated with perimetry. A defect in blue-yellow discrimination (tritan error axis) is the most common type of dyschromatopsia, however protan and deutan axes may be superimposed. A characteristic optic disk appearance includes temporal disk pallor with excavation. An autosomal dominant inheritance pattern can often be elicited from the family history.     

Transient monocular visual loss

Transient monocular visual loss may be caused by a variety of ophthalmic and systemic conditions. Management depends on identifying the cause. Embolic occlusions of arteries supplying the eye are a most important cause. Such emboli often arise from the heart, aorta, and internal carotid arteries. The most common embolic substances are white platelet-fibrin and red erythrocyte-fibrin thrombi, cholesterol crystals, and calcific particles. Retinal vasoconstriction is another important cause of transient monocular visual loss. The conditions that cause anterior ischemic optic neuropathy may occasionally cause transient visual loss. Transient monocular visual loss may also be related to conditions that cause papilledema and some conditions intrinsic to the eye, such as optic disk drusen and colobomas.     

Sprint car visual loss

A 16-year-old boy developed bilateral visual loss 24 hours after a sprint car accident. Bilateral central scotomas were demonstrated but were unexplained by a thorough eye examination and neuro-imaging. A diagnosis of commotio retinae was established by multi-focal ERG testing. This relatively new technique is discussed, including comparison to full-field ERG and clinical applications.     

Postoperative progressive visual loss

A 61-year-old man was admitted with postoperative progressive bilateral visual loss following a parasagittal meningioma resection. No risk factor predisposing to an ischemic optic neuropathy was present and routine radiologic examinations did not reveal any pathology of the central or peripheral visual pathways. Mucin-positive adenocarcinoma cells were detected in the cytological examination and orbital MRI revealed metastatic infiltration of the optic chiasm and optic nerves. The primary site of the malignancy could not be established.     

Transient monocular visual loss

PURPOSE: To provide a practical update on the diagnosis and management of transient monocular visual loss (TMVL). DESIGN: Perspective. METHODS: Review of the literature. RESULTS: TMVL is an important clinical symptom. It has numerous causes but most often results from transient retinal ischemia. It may herald permanent visual loss or a devastating stroke, and patients with TMVL should be evaluated urgently. A practical approach to the evaluation of the patient with TMVL must be based on the patient's age and the suspected underlying etiology. In the older patient, tests should be performed to investigate giant cell arteritis, atherosclerotic large vessel disease, and cardiac abnormalities. In the younger patient, TMVL is usually benign and the evaluation should be tailored to the particular clinical setting. CONCLUSIONS: Specific prevention strategies are tailored to the most likely cause of TMVL and the patient's underlying risk factors. Prevention of a future event should begin in the ophthalmologist's office with education and aggressive treatment of artherosclerotic risk factors.     

Sudden painless visual loss

Common signs and symptoms of temporal arteritis include headache, scalp tenderness, jaw claudication, anemia, and an elevated sedimentation rate (ESR). Severe complications can include blindness, retinal artery occlusion, and optic neuropathy. While temporal arteritis may be suggested by patient history, other causes that can mimic its presentation must be considered, especially when visual loss occurs in the setting of a normal funduscopic exam. We report a case of invasive sino-orbital aspergillosis that mimicked the clinical signs and symptoms typically associated with temporal arteritis. A high index of suspicion and appropriate radiological and laboratory studies prevented delays in formulating the correct diagnosis and treatment plan.     

Cone-rod dysfunction in patients with unexplained reduction in visual acuity

Electrophysiologic tests were performed in 233 patients who complained of reduced visual acuity with no satisfactory clinical explanation. The functional integrity of the retina was assessed from the light-and dark-adapted electroretinogram., Macular function and conduction in the optic nerves were estimated from the flash visual evoked potentials. Of the 233 patients 78 were grouped together on the basis of the electrophysiologic and clinical findings. They were characterized by subnormal electroretinogram responses with the cone system more affected than the rod system. The flash visual evoked potential responses were of abnormal waveform and prolonged implicit times. Most of these patients exhibited normal fundi. The reduction in visual acuity, the degree of electroretinogram deficits and the pattern of the visual evoked potential responses were similar in both eyes of each, patient, indicating a symmetric disorder. Slight deterioration of visual acuity and electrophysiologic variables were observed in 37 of the patients who were followed up over a period of up to 8 years. The electrophysiologic findings indicate that about 20% of patients complaining of unexplained reduction in visual acuity were suffering from a diffuse retinal disorder affecting the peripheral retina as well as the macular region. On the basis of electrophysiologic findings and clinical symptoms, we suggest grouping these patients under a new entity: cone-rod dysfunction.