Morphometric analysis of pars plana development in humans

Area of Science:

• Ophthalmology
• Pediatric Ophthalmology
• Ophthalmic Anatomy

Background:

• Quantitative data on human pars plana development is limited.
• Understanding pars plana dimensions is crucial for infant eye surgery.
• This study characterizes pars plana growth in relation to age and eye size.

Purpose of the Study:

• To provide a morphometric description of pars plana growth.
• To analyze pars plana development relative to postconceptional age.
• To examine the relationship between pars plana width and axial length.

Main Methods:

• Histologic specimens from 204 human eyes (10 weeks to 5 years) were analyzed.
• Axial length and temporal pars plana width were measured using a reticule system.
• Statistical analysis examined correlations between pars plana width, axial length, and postconceptional age.

Main Results:

• Rapid pars plana growth occurred between 26-35 weeks gestation.
• A linear relationship between pars plana width and axial length was observed after axial length reached 12 mm (r=0.918, P=0.0001).
• At 38-42 weeks postconception, mean pars plana width was 1.87 mm and mean axial length was 17.7 mm. By 62 weeks postconception, pars plana width was consistently >= 3 mm and axial length >= 19 mm.

Conclusions:

• Pars plana develops in the second trimester, with accelerated growth from 26-35 weeks gestation.
• Pars plana dimensions correlate strongly with axial length and postconceptional age.
• Pars plana vitreous surgery is feasible by 62 weeks postconception (approximately 6 months), assuming a 3 mm pars plana width is required.