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Parapapillary atrophy: histological gamma zone and delta zone.

Jonas JB, Jonas SB, Jonas RA, Holbach L, Dai Y, Sun X, Panda-Jonas S - PLoS ONE (2012)

Bottom Line: It was not significantly (P = 0.28) associated with axial length.Beta zone was significantly (P = 0.004) larger than the region with occluded choriocapillaris.It was not significantly (P = 0.24) associated with glaucomatous optic neuropathy.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Medical Faculty Mannheim of the Ruprecht-Karls-University Heidelberg, Germany. Jost.Jonas@umm.de

ABSTRACT

Background: To examine histomorphometrically the parapapillary region in human eyes.

Methodology/principal findings: The histomorphometric study included 65 human globes (axial length:21-37 mm). On anterior-posterior histological sections, we measured the distance Bruch's membrane end (BME)-optic nerve margin ("Gamma zone"), BME-retinal pigment epithelium (RPE) ("Beta zone"), BME-beginning of non-occluded choriocapillaris, and BME-beginning of photoreceptor layer. "Delta zone" was defined as part of gamma zone in which blood vessels of at least 50 µm diameter were not present over a length of >300 µm. Beta zone (mean length:0.35±0.52 mm) was significantly (P = 0.01) larger in the glaucoma group than in the non-glaucomatous group. It was not significantly (P = 0.28) associated with axial length. Beta zone was significantly (P = 0.004) larger than the region with occluded choriocapillaris. Gamma zone (mean length:0.63±1.25 mm) was associated with axial length (P<0.001;r(2) = 0.73) with an increase starting at an axial length of 26.5 mm. It was not significantly (P = 0.24) associated with glaucomatous optic neuropathy. Delta zone (present only in eyes with axial length of ≥27 mm) was associated with axial length (P = 0.001) and scleral flange length (P<0.001) but not with glaucoma (P = 0.73).

Conclusions/significance: Parapapillary gamma zone (peripapillary sclera without overlying choroid, Bruch's membrane and deep retinal layers) was related with axial globe elongation and was independent of glaucoma. Delta zone (no blood vessels >50 µm diameter within gamma zone) was present only in highly axially elongated globes and was not related with glaucoma. Beta zone (Bruch's membrane without RPE) was correlated with glaucoma but not with globe elongation. Since the region with occluded choriocapillaris was smaller than beta zone, complete loss of RPE may have occurred before complete choriocapillaris closure.

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Related in: MedlinePlus

Scatterplot showing the distribution size of gamma zone versus axial length (locally weighted scatterplot smoothing (LOESS) statistics).
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pone-0047237-g005: Scatterplot showing the distribution size of gamma zone versus axial length (locally weighted scatterplot smoothing (LOESS) statistics).

Mentions: Mean length of gamma zone was 0.63±1.25 mm (median: 0; range: 0 to 6.19 mm). In univariate analysis, gamma zone was not significantly associated with age (P = 0.84) nor gender (P = 0.76). In the non-highly elongated group (axial length ≤26.0 mm), the glaucomatous group and the non-glaucomatous group did not vary significantly in size of gamma zone (0.03±0.08 mm versus 0.03±0.07 mm; P = 0.71). In a similar manner in the highly elongated group (axial length >26.0 mm), the glaucomatous group and the non-glaucomatous group did not vary significantly in size of gamma zone (0.75±1.21 mm versus 0.83±1.18 mm; P = 0.86). Gamma zone size was not significantly related with vertical globe diameter (P = 0.18) and horizontal globe diameter (P = 0.08). Size of gamma zone significantly increased with axial length in a non-linear manner (P<0.001; quadratic regression correlation coefficient r2 = 0.73). In a LOESS (locally weighted scatterplot smoothing) statistics, the increase in gamma zone size started at an axial length of about 26.5 mm (Fig. 5). Gamma zone size was significantly correlated with the thickness of the peripapillary scleral flange (P<0.001; quadratic regression correlation coefficient r2 = 0.68). In a LOESS statistics, the increase in gamma zone size started at a thickness of the peripapillary scleral flange of 0.3 mm or less (Fig. 6). Size of gamma zone significantly increased with the length of the peripapillary scleral flange (P<0.001; r2 = 0.74; equation of the regression line: Length of Gamma zone = 1.61×Length of Scleral Flange −0.52 mm). The diagram showed a steep increase in the length of gamma zone starting a scleral flange length of 0.8 mm (Fig. 7).


Parapapillary atrophy: histological gamma zone and delta zone.

Jonas JB, Jonas SB, Jonas RA, Holbach L, Dai Y, Sun X, Panda-Jonas S - PLoS ONE (2012)

Scatterplot showing the distribution size of gamma zone versus axial length (locally weighted scatterplot smoothing (LOESS) statistics).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3475708&req=5

pone-0047237-g005: Scatterplot showing the distribution size of gamma zone versus axial length (locally weighted scatterplot smoothing (LOESS) statistics).
Mentions: Mean length of gamma zone was 0.63±1.25 mm (median: 0; range: 0 to 6.19 mm). In univariate analysis, gamma zone was not significantly associated with age (P = 0.84) nor gender (P = 0.76). In the non-highly elongated group (axial length ≤26.0 mm), the glaucomatous group and the non-glaucomatous group did not vary significantly in size of gamma zone (0.03±0.08 mm versus 0.03±0.07 mm; P = 0.71). In a similar manner in the highly elongated group (axial length >26.0 mm), the glaucomatous group and the non-glaucomatous group did not vary significantly in size of gamma zone (0.75±1.21 mm versus 0.83±1.18 mm; P = 0.86). Gamma zone size was not significantly related with vertical globe diameter (P = 0.18) and horizontal globe diameter (P = 0.08). Size of gamma zone significantly increased with axial length in a non-linear manner (P<0.001; quadratic regression correlation coefficient r2 = 0.73). In a LOESS (locally weighted scatterplot smoothing) statistics, the increase in gamma zone size started at an axial length of about 26.5 mm (Fig. 5). Gamma zone size was significantly correlated with the thickness of the peripapillary scleral flange (P<0.001; quadratic regression correlation coefficient r2 = 0.68). In a LOESS statistics, the increase in gamma zone size started at a thickness of the peripapillary scleral flange of 0.3 mm or less (Fig. 6). Size of gamma zone significantly increased with the length of the peripapillary scleral flange (P<0.001; r2 = 0.74; equation of the regression line: Length of Gamma zone = 1.61×Length of Scleral Flange −0.52 mm). The diagram showed a steep increase in the length of gamma zone starting a scleral flange length of 0.8 mm (Fig. 7).

Bottom Line: It was not significantly (P = 0.28) associated with axial length.Beta zone was significantly (P = 0.004) larger than the region with occluded choriocapillaris.It was not significantly (P = 0.24) associated with glaucomatous optic neuropathy.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Medical Faculty Mannheim of the Ruprecht-Karls-University Heidelberg, Germany. Jost.Jonas@umm.de

ABSTRACT

Background: To examine histomorphometrically the parapapillary region in human eyes.

Methodology/principal findings: The histomorphometric study included 65 human globes (axial length:21-37 mm). On anterior-posterior histological sections, we measured the distance Bruch's membrane end (BME)-optic nerve margin ("Gamma zone"), BME-retinal pigment epithelium (RPE) ("Beta zone"), BME-beginning of non-occluded choriocapillaris, and BME-beginning of photoreceptor layer. "Delta zone" was defined as part of gamma zone in which blood vessels of at least 50 µm diameter were not present over a length of >300 µm. Beta zone (mean length:0.35±0.52 mm) was significantly (P = 0.01) larger in the glaucoma group than in the non-glaucomatous group. It was not significantly (P = 0.28) associated with axial length. Beta zone was significantly (P = 0.004) larger than the region with occluded choriocapillaris. Gamma zone (mean length:0.63±1.25 mm) was associated with axial length (P<0.001;r(2) = 0.73) with an increase starting at an axial length of 26.5 mm. It was not significantly (P = 0.24) associated with glaucomatous optic neuropathy. Delta zone (present only in eyes with axial length of ≥27 mm) was associated with axial length (P = 0.001) and scleral flange length (P<0.001) but not with glaucoma (P = 0.73).

Conclusions/significance: Parapapillary gamma zone (peripapillary sclera without overlying choroid, Bruch's membrane and deep retinal layers) was related with axial globe elongation and was independent of glaucoma. Delta zone (no blood vessels >50 µm diameter within gamma zone) was present only in highly axially elongated globes and was not related with glaucoma. Beta zone (Bruch's membrane without RPE) was correlated with glaucoma but not with globe elongation. Since the region with occluded choriocapillaris was smaller than beta zone, complete loss of RPE may have occurred before complete choriocapillaris closure.

Show MeSH
Related in: MedlinePlus