Novel Findings about Myopia in Patients with Oculodermal Melanocytosis (Nevus of Ota).

Purpose: To test the hypothesis that ocular pigment in patients with oculodermal melanocytosis decreases myopia severity.Methods: Refractive and biometric parameters were measured and compared between pigmented eyes and non-pigmented contralateral eyes in oculodermal melanocytosis patients that underwent surgical ocular pigmentation removal. To assess pigmentation, the pigmentation score was measured in each quadrant of the sclera and added together for a cumulative score. For subgroup analyses, patients were categorized into three groups according to the severity of myopia in the non-pigmented eye.Results: Fifty-five patients (110 eyes) were included. Spherical power and spherical equivalent were significantly less myopic in pigmented eyes relative to contralateral non-pigmented eyes. The spherical powers of non-pigmented eyes were positively correlated with the difference in spherical power between contralateral eyes (r = 0.697, p < .001). The pigmentation scores of pigmented eyes were positively correlated with the ratio of myopia inhibition (r = 0.373, p = .005). In subgroup analyses, pigmented eyes exhibited significantly less myopic spherical powers and spherical equivalents than non-pigmented contralateral eyes in the moderate and high myopia groups. Pigmented eyes exhibited significantly shorter axial length than non-pigmented contralateral eyes in the high myopia group only.Conclusions: In patients with oculodermal melanocytosis, pigmented eyes exhibited less severe myopia relative to non-pigmented contralateral eyes. This suggested that ocular pigmentation inhibited myopic changes, potentially by blocking UV transmission. This study will be helpful in elucidating the mechanisms of myopic progression.

Nevus of Ota, a classic presentation / Nevus de Ota de presentación clásica

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Comparison of acquired bilateral nevus of Ota-like macules in men and women.

BACKGROUND: The clinical and histopathological characteristics of acquired bilateral nevus of Ota-like macules in men are poorly documented due to its rarity. AIMS: To compare the clinical and histopathological characteristics of acquired bilateral nevus of Ota-like macules in men with the condition in women. METHODS: We studied 11 men and 62 women, all with a clinical diagnosis of acquired bilateral nevus of Ota-like macules. Biopsies were taken from 5 men and 10 women and their clinical and histopathological features were compared. RESULTS: The most frequently affected site in men was the forehead [8 (73%) out of 11 patients]. Lesions on the forehead were more common in men than women (P = 0.001). In contrast to women, there was no apparent tendency of the lesions to become more blue with age in men. Concurrent melasma was observed in 14 (23%) out of 62 women, but not in men. Extra-facial acquired dermal melanocytosis was noted in 2 (18%) out of 11 men and in none of the 62 women. CONCLUSION: Significant differences were noted between men and women in the appearance of concurrent pigmentary lesions and the distribution of lesions. Extra-facial acquired dermal melanocytosis was noted in men.

[Normal and abnormal skin color]. / La couleur de la peau normale ou anormale.

The varieties of normal skin color in humans range from people of "no color" (pale white) to "people of color" (light brown, dark brown, and black). Skin color is a blend resulting from the skin chromophores red (oxyhaemoglobin), blue (deoxygenated haemoglobin), yellow-orange (carotene, an exogenous pigment), and brown (melanin). Melanin, however, is the major component of skin color ; it is the presence or absence of melanin in the melanosomes in melanocytes and melanin in keratinocytes that is responsible for epidermal pigmentation, and the presence of melanin in macrophages or melanocytes in the dermis that is responsible for dermal pigmentation. Two groups of pigmentary disorders are commonly distinguished: the disorders of the quantitative and qualitative distribution of normal pigment and the abnormal presence of exogenous or endogenous pigments in the skin. The first group includes hyperpigmentations, which clinically manifest by darkening of the skin color, and leukodermia, which is characterized by lightening of the skin. Hypermelanosis corresponds to an overload of melanin or an abnormal distribution of melanin in the skin. Depending on the color, melanodermia (brown/black) and ceruloderma (blue/grey) are distinguished. Melanodermia correspond to epidermal hypermelanocytosis (an increased number of melanocytes) or epidermal hypermelanosis (an increase in the quantity of melanin in the epidermis with no modification of the number of melanocytes). Ceruloderma correspond to dermal hypermelanocytosis (abnormal presence in the dermis of cells synthesizing melanins) ; leakage in the dermis of epidermal melanin also exists, a form of dermal hypermelanosis called pigmentary incontinence. Finally, dyschromia can be related to the abnormal presence in the skin of a pigment of exogenous or endogenous origin.

Light and electron microscopic investigation of the process of healing of the naevus of Ota by Q-switched alexandrite laser irradiation.

Melanocytes in the naevus of Ota were destroyed by irradiation using the Q-switched alexandrite laser. This laser is highly selective and highly absorbed by melanosomes. Other cells and tissue components of the dermis remained almost intact. Melanosomes were vaporized or fragmented to subelectron microscopical size, or degenerated. If the irradiated energy was sufficient, melanocytes vanished and large vacuoles several times the size of dermal melanocytes formed at the sites. If it was too weak, dermal melanocytes were also vaporized, but vacuoles formed within them. Nuclei were no longer discernible. Following irradiation macrophages infiltrated the irradiated areas and scavenged degenerated melanosomes and cellular debris. Thus, discoloration of the skin was markedly reduced. Although a few melanocytes and melanophages remained, pigmentation cleared to a satisfactory level. Melanocytes and keratinocytes were also injured in the epidermis; however, the epidermis recovered completely. No scarring was observed.

Dermal melanocytosis: a clinical spectrum.

While most dermal melanocytoses are congenital or have an onset in early childhood, there is a group which is clearly acquired, with an onset in adult life. While the Mongolian spot typically disappears in childhood, other dermal melanocytoses persist for life. A brief review of the clinical spectrum of the dermal melanocytoses is undertaken and three illustrative cases are described: a case of congenital naevus of Ota, a case of acquired bilateral naevus of Ota-like macules, and an unusual case of a congenital dermal melanocytotic lesion on the left had which began to spread in adulthood. The possibilities regarding the pathogenesis of this intriguing group of disorders are considered.

[Ocular site of pigmentation in oculodermal melanocytosis]. / Localisation oculaire de la pigmentation dans la mélanocytose oculodermique.

Sixteen patients with oculodermal melanocytosis (Nevus of Ota, congenital ocular melanocytosis) were investigated for the location and the density of the ocular pigmentation, the increase in intraocular location and the malignant transformation. In all cases, conjunctivo-scleral dispersion pattern appeared as dispersed patches without any predominant site but a diffuse involvement of the angle. This finding points out that ODM may exhibit a characteristic dispersion pattern of pigmentation which is characteristic for ODM. For 14 patients intraocular pressures were < or = 18 mmHg, and for remaining 2 patients 21 and 22 mm Hg. Glaucomatous optic disc or perimetric changes were not found in any patient. In one case, a histologically verified ciliary-choroidal melanoma at a superior-temporal site co-existed at the same location as the ODM.

A new neurocutaneous syndrome possibly related to Ota's nevus.

The case of a 42-year-old Sudanese man is reported who had developed hyperpigmentation of the left face and rapidly progressive right hemiparesis followed by myoclonus at the age of 30. Blue-grey hyperpigmentation was noted in the territory of the left ophthalmic, maxillary and mandibular trigeminal nerve branches, with alopecia of the right face and axilla. CT of the brain revealed left-sided paraventricular calcifications and MRI showed atrophy of the left cerebral hemisphere and mesencephalon, a calcified haemangioma in the left basal ganglia, an old infarct in the right central pons, and cerebellar atrophy. This case resembles Ota's syndrome; however, atypical distribution of the facial nevus, the epidermal location of hyperpigmentation, and the combination of vascular and degenerative cerebral malformations indicate that this is a new hitherto unreported neurocutaneous vascular syndrome.