Abstract
Purpose: :
To develop an anterior segment ocular computer tomography (AS-OCT) algorithm to preoperatively determine the optimal size of donor graft for DSAEK surgery and suitability for insertion of anterior chamber (AC) phakic intraocular lenses (IOLs), using the Zhongshan Assessment Program (ZAP, Guangzhou, China), an imaging analysis software measuring anterior segment parameters with the Carl Zeiss Visante AS-OCT.
Methods: :
Cross-sectional, observational study of 750 consecutive phakic right eyes of healthy Chinese patients aged 50 years and above. We included posterior corneal arc lengths (PCAL), a novel parameter defined as the posterior corneal border distance between scleral spurs.
Results: :
Mean age of 63.3 +/- 7.9 years with 349 males and 401 females. Anterior segment parameters measured were posterior corneal arc length (PCAL) (12.924 +/- 0.544 mm), anterior chamber depth (ACD) (2.684 +/- 0.309 mm), central corneal thickness (CCT) (562.39 +/- 31.85 µm), anterior corneal curvature (ACC) (7.35 +/- 0.37 mm) and posterior corneal curvature (PCC) (6.65 +/- 0.34 mm). ACC has a positive correlation with PCC (R2 = 0.67, p < 0.001). There was no correlation between PCAL and other corneal parameters, and no correlation was found between age and ACD (R2 = 0.03), CCT (0.02), PCAL (0.008), ACC (0.00) or PCC (0.00).
Conclusions: :
Determination of corneal parameters using the ZAP program allows for fast, non-invasive analysis of the anterior segment. This is the largest series of PCAL measurements for Chinese eyes providing a comparative demographic baseline for optimizing DSAEK donor graft size, suitability for insertion of AC phakic IOLs and for comparison with demographic data of other ethnic groups, whilst offering useful information for prospective studies in lamellar and refractive procedures.
Keywords: imaging/image analysis: clinical • anterior segment • cornea: clinical science