Pupil size affects coma value in certain eyes

When compared with eyes of normal axial length, high-myopic pseudophakic eyes with posterior staphyloma had significantly less internal coma and less coma variations during mydriasis, according to research published in Eye.

The researchers studied 60 eyes: 40 in highly myopic cataract patients with posterior staphyloma and 20 in cataract patients with normal axial length.

They found that the high-myopic pseudophakic eyes with posterior staphyloma had significantly lower values of internal coma - both under 4 mm and 6 mm pupil sizes - at 1 month after phacoemulsification and IOL implantation compared to eyes with normal axial length.

The high-myopic pseudophakic eyes with posterior staphyloma also had significantly lower internal total higher-order aberrations and third-order aberrations at 6-mm pupil size.

In addition, the researchers found statistically significant differences between the two groups in the variation from 4- to 6-mm pupil sizes for:

• internal coma
• internal third-order aberrations

• internal total higher-order aberrations
• ocular coma aberrations.

Strehl ratio increased significantly in high-myopic eyes and decreased slightly in normal axial length eyes after mydriasis, and modular transfer functions were found to vary in a statistically significant manner between the two groups at frequencies of 15, 30, 45 and 60 cycles/degree.

To read an abstract of the study, click here.