Abstract
Purpose:
To examine histomorphometrically the macular region of highly myopic eyes
Methods:
On horizontal anterior-posterior histological sections, we examined the region of the macula and optic nerve head of 138 human globes (axial length:20-35mm). In the parapapillary region, we differentiated between beta zone (Bruchs membrane without retinal pigment epithelium (RPE)), gamma zone (parapapillary region without Bruchs membrane), and delta zone (elongated and thinned gamma zone).
Results:
In 12 (8.7%) eyes, a macular Bruchs membrane defect (MBMD) was detected. The MBMD showed a complete lack of RPE and choriocapillaris, and an almost complete lack of photoreceptors. Presence of MBMD was associated with longer axial length (P<0.001), longer gamma zone (P=0.04) and delta zone (P<0.001), thinner peripapillary scleral flange, and lower thickness of the sclera just outside of the optic nerve meninges (P<0.001) and at the posterior pole (P<0.001). A MBMD was found only in eyes with an axial length of ≥27 mm. Presence of a MBMD was not significantly related to length of beta zone of parapapillary atrophy (P=0.09). In multivariate binary regression analysis, MBMD presence was significantly (P<0.001) associated only with axial length.
Conclusions:
Highly myopic eyes (axial length ≥27mm) can show a MBMD associated with complete loss of RPE and choriocapillaris, and marked reduction of photoreceptors and large choroidal vessels. MBMD presence was strongly associated with axial length and indirectly with parapapillary gamma zone and delta zone. The myopia associated secondary MBMDs may occur parallel to the myopia associated widening of Bruchs membrane opening around the optic nerve head.
Keywords: 605 myopia •
688 retina •
585 macula/fovea