Peripapillary hyper-reflective ovoid mass-like structures (PHOMS): clinical significance, associations, and prognostic implications in ophthalmic conditions

Optic disc edema in raised intracranial pressure was first described in 1853. Ever since, there has been a plethora of controversial hypotheses to explain its pathogenesis. I have explored the subject comprehensively by doing basic, experimental and clinical studies. My objective was to investigate the fundamentals of the subject, to test the validity of the previous theories, and finally, based on all these studies, to find a logical explanation for the pathogenesis. My studies included the following issues pertinent to the pathogenesis of optic disc edema in raised intracranial pressure: the anatomy and blood supply of the optic nerve, the roles of the sheath of the optic nerve, of the centripetal flow of fluids along the optic nerve, of compression of the central retinal vein, and of acute intracranial hypertension and its associated effects. I found that, contrary to some previous claims, an acute rise of intracranial pressure was not quickly followed by production of optic disc edema. Then, in rhesus monkeys, I produced experimentally chronic intracranial hypertension by slowly increasing in size space-occupying lesions, in different parts of the brain. Those produced raised cerebrospinal fluid pressure (CSFP) and optic disc edema, identical to those seen in patients with elevated CSFP. Having achieved that, I investigated various aspects of optic disc edema by ophthalmoscopy, stereoscopic color fundus photography and fluorescein fundus angiography, and light microscopic, electron microscopic, horseradish peroxidase and axoplasmic transport studies, and evaluated the effect of opening the sheath of the optic nerve on the optic disc edema. This latter study showed that opening the sheath resulted in resolution of optic disc edema on the side of the sheath fenestration, in spite of high intracranial CSFP, proving that a rise of CSFP in the sheath was the essential pre-requisite for the development of optic disc edema. I also investigated optic disc edema with raised CSFP in patients, by evaluating optic disc and fundus changes by stereoscopic fundus photography and fluorescein fundus angiography. Based on the combined information from all the studies discussed above, it is clear that the pathogenesis of optic disc edema in raised intracranial pressure is a mechanical phenomenon. It is primarily due to a rise of CSFP in the optic nerve sheath, which produces axoplasmic flow stasis in the optic nerve fibers in the surface nerve fiber layer and prelaminar region of the optic nerve head. Axoplasmic flow stasis then results in swelling of the nerve fibers, and consequently of the optic disc. Swelling of the nerve fibers and of the optic disc secondarily compresses the fine, low-pressure venules in that region, resulting in venous stasis and fluid leakage; that leads to the accumulation of extracellular fluid. Contrary to the previous theories, the various vascular changes seen in optic disc edema are secondary and not primary. Thus, optic disc edema in raised CSFP is due to a combination of swollen nerve fibers and the accumulation of extracellular fluid. My studies also provided information about the pathogeneses of visual disturbances in raised intracranial pressure.

To describe progressive tilting of the optic nerve head (ONH) and development/enlargement of parapapillary atrophy (PPA) observed in children with incipient myopia and to investigate factors associated with such changes. Retrospective, observational study. This study included 118 eyes of 118 Korean children who were assessed by serial disc photography at intervals of 1 year or more. All disc photographs were reviewed by 2 experienced ophthalmologists, and eyes were classified into 2 groups with respect to the change in the ONH appearance and development/enlargement of β-zone PPA: (1) ONH/PPA changed group and (2) ONH/PPA unchanged group. To quantify the ONH/PPA changes, the ratio of the horizontal to vertical disc diameter (HVDR) and the ratio of the maximum PPA width to vertical disc diameter (PVDR) were measured. Factors associated with ONH/PPA changes were evaluated using logistic regression analysis. Refractive errors were measured with cycloplegic refraction. Morphologic changes of the ONH/PPA as observed in serial disc photographs and its association with myopic shift. Mean subject age and refractive error at the time of initial fundus examination were 7.3 ± 3.7 years (range, 1-17 years) and -0.9 ± 1.9 diopters (range, -5.9 to +3.0 diopters), respectively. Mean follow-up period was 38.1 ± 19.6 months (range, 12-88 months). Fifty-one eyes (43%) were classified as the ONH/PPA change group. In the ONH/PPA change group, HVDR decreased from the initial value of 0.92 ± 0.08 to the final value of 0.86 ± 0.11, and the PVDR increased from the initial value of 0.08 ± 0.07 to the final value of 0.20 ± 0.11. The ONH/PPA changes were most remarkable in subjects between 7 and 9 years of age (odds ratio [OR] = 6.698; 95% confidence interval [CI], 2.296-19.546) and were associated with greater myopic shift during the follow-up period (OR = 0.483; 95% CI, 0.345-0.676). We demonstrate progressive tilting of the ONH, which was observed with development/enlargement of PPA in children who exhibited myopic shift. These findings suggest that tilted disc, as well as PPA, may be an acquired feature in myopic eyes, arising from scleral stretching. The author(s) have no proprietary or commercial interest in any materials discussed in this article. Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Making an accurate diagnosis of optic disc drusen (ODD) is important as part of the work-up for possible life-threatening optic disc edema. It also is important to follow the slowly progressive visual field defects many patients with ODD experience. The introduction of enhanced depth imaging optical coherence tomography (EDI-OCT) has improved the visualization of more deeply buried ODD. There is, however, no consensus regarding the diagnosis of ODD using OCT. The purpose of this study was to develop a consensus recommendation for diagnosing ODD using OCT.