Multifocal electroretinography response after laser photocoagulation of a subretinal nematode

Diffuse unilateral subacute neuroretinitis: review article

Diffuse unilateral subacute neuroretinitis (DUSN) is an ocular infectious disease that can lead to severe visual impairment and blindness. It usually occurs in healthy young individuals and depending on the stage of the disease, it may present as vitritis, multifocal gray-white lesions in the outer retina, and derangement of the retinal pigment epithelium, narrowing of the retinal vessels and optic atrophy. Parasites of different sizes and species have been proposed as the etiologic agent of DUSN, including Ancylostoma caninum, Toxocara canis, and others. Thus, it is hypothesized that different infectious worms may be considered as the likely cause of both an autoimmune and toxic form of nematode retinopathy. Because serologic testing is variable, the definitive diagnosis is made when clinical characteristics of DUSN are found in conjunction with an intraocular worm. Ancillary tests can assist in the differential diagnosis when the nematode cannot be visualized, such as fluorescein and indocyanine green angiography, electrophysiological tests, visual field studies, and more recently, optical coherence tomography angiography. Cases in which the worm can be identified, it is defined as confirmed DUSN, and eyes with the typical clinical features but without identification of the worm should be classified as presumed DUSN. In confirmed DUSN, the classic treatment is directly photocoagulation of the worm; however, it can only be visualized in 30% (to 40%) of cases. Treatment of presumed DUSN cases with high-dose oral albendazole has shown encouraging results. However, perhaps due to the disease’s rarity or its underdiagnosis, there are no studies comparing current treatment modalities in both presumed and confirmed DUSN. Due to the possibility of this disease being, in part, autoimmune nematode retinopathy, corticosteroids associated with both albendazole or laser therapy, could be in any way beneficial. Thus, further comparative studies are necessary to elucidate the best treatment for this potentially blinding disease.

Diffuse unilateral subacute neuroretinitis

Diffuse unilateral subacute neuroretinitis (DUSN) is a usually unilateral inflammatory disease characterized by an insidious, usually severe loss of peripheral and central vision. Clinical characteristics are manifested in early and late stages. Parasites of different sizes and several species of nematodes have been reported as the etiology of DUSN without conclusive evidence about the specific agent. Because serologic testing has been variable, the definitive diagnosis is made when the clinical characteristics of DUSN are found in conjunction with an intraocular worm. Laser photocoagulation, pars plana vitrectomy, thiabendazole, and albendazole have been used to treat DUSN with variable success.

Congenital nasolacrimal duct obstruction in premature children

PURPOSE

To determine the incidence of congenital nasolacrimal duct obstruction (CNLDO) in premature and full-term children.

METHODS

Medical records of 200 premature and 200 full-term children from July 2004 to November 2009 at the Peri-Peri Health Center were retrospectively reviewed. Fifty-three nasolacrimal ducts in 32 premature children (21 patients were bilateral) and 9 nasolacrimal ducts in 7 full-term children (2 patients were bilateral) diagnosed as having CNLDO were retrospectively examined.

RESULTS

Of the 200 premature children, 32 (16%) had CNLDO compared with 7 (3.5%) of the 200 full-term infants (P < .0001). Thirty premature infants and five full-term children underwent conservative treatment. Bilateral obstruction was found in all 3 extremely premature children (gestational age < 28 weeks), in 9 (69.23%) moderately premature children (gestational age of 28 to 31 weeks), in 9 (56.25%) mildly premature children (gestational age of 32 to 36 weeks), and in 2 (28.57%) full-term children (gestational age > 37 weeks).

CONCLUSIONS

This study reported a higher incidence of CNLDO in preterm infants when compared to full-term infants. This might be expected in light of the normal development of the nasolacrimal duct system, the patency of which normally occurs after the preterm infant is born.

Myiasis

Myiasis is defined as the infestation of live vertebrates (humans and/or animals) with dipterous larvae. In mammals (including humans), dipterous larvae can feed on the host's living or dead tissue, liquid body substance, or ingested food and cause a broad range of infestations depending on the body location and the relationship of the larvae with the host. In this review, we deeply discuss myiasis as a worldwide infestation with different agents and with its broad scenario of clinical manifestations as well as diagnosis techniques and treatment.

Ophthalmomyiasis with a singular subretinal track

PURPOSE

To report 3 cases of myiasis with a singular subretinal track in the Northeastern part of United States.

DESIGN

Noninterventional case series.

METHODS

Three patients from Pennsylvania were referred for evaluation of a linear and serpiginous retinal scar. Funduscopic examination and fluorescein angiography were performed to assess the referred retinal lesion.

RESULTS

Funduscopic examination showed a singular subretinal track from the superior periphery to either the posterior pole or inferior midperiphery in the study cases. Fluorescein angiography showed exudative retinal detachment in all 3 cases. Laser photocoagulation of the subretinal worm was performed in all reported cases.

CONCLUSIONS

Our case series represents a report of singular subretinal tracks presumably caused by the warble fly larva in the Northeastern part of United States.

Diffuse unilateral subacute neuroretinitis: report of a case from the Indian subcontinent and the importance of immediate photocoagulation

PURPOSE

To report a case of DUSN from the Indian subcontinent and emphasize the importance of immediate photocoagulation.

METHOD

Review of case record.

RESULT

The referring ophthalmologist had photographed the subretinal worm but had not undertaken laser photocoagulation. On presentation to us the patient had features typical of DUSN but no worm could be detected despite repeated examinations. Failure to localize the worm at subsequent examinations resulted in only partial recovery of vision.

CONCLUSION

Whenever the nematode is detected, immediate laser photocoagulation of the worm is necessary as the migratory worm may be difficult to identify later on. This is necessary to prevent the otherwise natural decline in vision.

The clinical applications of multifocal electroretinography: a systematic review

Multifocal electroretinography (mfERG) is an investigation that can simultaneously measure multiple electroretinographic responses at different retinal locations by cross-correlation techniques. mfERG therefore allows topographic mapping of retinal function in the central 40-50 degrees of the retina. The strength of mfERG lies in its ability to provide objective assessment of the central retinal function at different retinal areas within a short duration of time. Since the introduction of mfERG in 1992, mfERG has been applied in a large variety of clinical settings. This article reviews the clinical applications of mfERG based on the currently available evidence. mfERG has been found to be useful in the assessment of localized retinal dysfunction caused by various acquired or hereditary retinal disorders. The use of mfERG also enabled clinicians to objectively monitor the treatment outcomes as the changes in visual functions might not be reflected by subjective methods of assessment. By changing the stimulus, recording, and analysis parameters, investigation of specific retinal electrophysiological components can be performed topographically. Further developments and consolidations of these parameters will likely broaden the use of mfERG in the clinical setting.