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JCRS HIGHLIGHTS

Soosan Jacob

Posted: Wednesday, March 30, 2016

LONG-TERM CATARACT OUTCOMES

Patients undergoing cataract surgery can expect good long-term visual rehabilitation, a prospective longitudinal population-based cohort study conducted in Sweden suggests. The study included 190 patients who were interviewed and evaluated 15 years after undergoing surgery in a similar time frame. Fifteen years after surgery, the median corrected distance visual acuity (CDVA) in the operated eye had deteriorated from 20/20 postoperatively to 20/25 (P = .0001). Sixty per cent of the patients had worsening of CDVA of less than 0.1 logMAR units compared with postoperatively. All patients answered the same Visual Function-14 (VF-14) questionnaire preoperatively, four months postoperatively, and five, 10 and 15 years after surgery. Fifty-four per cent had no deterioration in subjective visual function, and 79 per cent had 10 points of decline or less. Previous Nd:YAG laser capsulotomy was more common in those younger than 65 years at surgery (49 per cent versus 25 per cent), which was highly statistically significant. The most common comorbidity causing large functional loss 15 years after surgery was age-related macular degeneration.
E Monestam, JCRS, “Long-term outcomes of cataract surgery: 15-year results of a prospective study”, Volume 42, Issue 1, 19-26.

 

OCT BIOMETRY

Axial length and anterior chamber depth are commonly measured with partial-coherence interferometry (PCI) or optical low-coherence reflectometry (OLCR) biometers. The OLCR biometer also measures the central corneal thickness, aqueous depth, lens thickness, pupil size, and corneal diameter. However, both biometers are known to fall short in determining the axial length in the presence of a dense nuclear and/or posterior subcapsular cataract. US researchers conducted a prospective evaluation of a new biometer (Argos) with swept-source optical coherence tomography (SS-OCT), and compared results with those obtained with the PCI and the OLCR biometers. They measured axial length, central corneal thickness, aqueous depth, anterior chamber depth, lens thickness, pupil size, corneal diameter, and anterior corneal radius of curvature (RAV). Measurements with the new SS-OCT biometer were repeatable and reproducible. Axial length measurements with the new biometer were comparable to PCI and OLCR measurements, with a faster and higher acquisition rate, even in the presence of a dense nuclear or posterior subcapsular cataract. The new system moved beyond current systems capabilities by using a swept-source that implements quasi-phase continuous tuning combined with multiple beam expanders at a swept rate of 2.5kHz, which is about five to 10 times larger than what can be achieved in current systems.
This swept-source enables very simple measurements of the
axial length.
H John Shammas et al, JCRS, “Biometry measurements using a new large-coherence–length swept-source optical coherence tomographer”, Volume 42, Issue 1, 50-61.