The effect of simulated cataract light scatter on retinal vessel oximetry

Patel, Samip; Hudson, Chris; Flanagan, John G.; Heitmar, Rebekka

doi:10.1016/j.exer.2013.09.004

Cited by 16 publications

(22 citation statements)

References 27 publications

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“…Previous reports have shown that the measurement of arterial and venous retinal oxygen saturation tended to be lower in images of poor quality 16,17. To minimize the effects of cataract in this study, we excluded 26 patients, whose “image quality” was <6.0 before surgery.…”

Section: Discussionmentioning

confidence: 91%

The effect of vitreomacular and cataract surgery on oxygen saturation in retinal vessels

Nakano¹,

Manabe²,

Osaka³

et al. 2017

OPTH

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PurposeTo evaluate the effects of vitreomacular and cataract surgery on retinal oximetry in vitreomacular disease.Patients and methodsThirty-eight eyes with epiretinal membrane (ERM) and 15 with idiopathic macular hole (MH) underwent 25 gauge pars plana vitrectomy combined with cataract surgery and intraocular lens implantation. Retinal oximetry was performed using the Oxymap T1 before, 1 month, and 6 months after surgery. Oxymap T1 simultaneously captures monochrome images of the fundus at two different wavelengths of light. Built-in Oxymap Analyzer software measures the oxygen saturation and vessel diameter.ResultsMean arterial oxygen saturation significantly increased from 96.8%±6.2% to 100.2%±5.8% at 1 month and to 99.6%±5.8% at 6 months after surgery (P<0.01). Mean venous oxygen saturation also significantly increased from 54.6%±7.5% to 61.2%±6.4% at 1 month and to 62.6%±5.9% at 6 months after surgery (P<0.01). Mean arteriovenous (A-V) difference decreased from 42.2%±6.6% to 39.0%±7.8% at 1 month and to 37.0%±6.9% at 6 months after surgery (P<0.01). The ERM and MH groups showed similar changes in retinal oxygen saturation. However, there were no significant changes in the caliber of major retinal vessels after surgery (from 125.2±15.2 μm to 124.0±15.4 μm in artery, from 168.7±14.6 μm to 169.8±14.6 μm in vein).ConclusionOxymap T1 was able to measure the increase in oxygen saturation in retinal arteries and veins, which led to a decrease in the A-V difference in oxygen saturation after vitrectomy combined with cataract surgery.

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Section: Discussionmentioning

confidence: 91%

The effect of vitreomacular and cataract surgery on oxygen saturation in retinal vessels

Nakano¹,

Manabe²,

Osaka³

et al. 2017

OPTH

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“…In vivo , Patel et al. () introduced an additional plano lens filled with a polybead solution that simulated light scatter to mimic the changes in lens morphology. The light scatter model used in this study incorporated polybead microspheres, mimicking a forward light scatter similar to that produced by the ultra‐structural features of human lens fibre cells (Costello et al.…”

Section: Discussionmentioning

confidence: 99%

Preoperative and postoperative measurements of retinal vessel oxygen saturation in patients with different grades of cataracts

Chen

Lin

Chen

et al. 2016

Acta Ophthalmologica

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“…We previously explored the effects of scatter on dual‐wavelength oximetry (Patel et al. ) and were able to demonstrate that simulated light scatter alters retinal vessel oximetry parameters. One of the limitations of this study was the small numbers of participants, vessels assessed and image size due to the optical set‐up.…”

Section: Discussionmentioning

confidence: 99%

“…Vessel saturation calculations depend on the absorption spectra, which in turn can be affected by light scatter, media opacity and illumination (Heitmar & Cubbidge ; Patel et al. ). We have previously explored the influence of light scatter using a polybead model (Patel et al.…”

Section: Introductionmentioning

confidence: 99%

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The influence of simulated cataract on retinal vessel oximetry measurements

Heitmar

Attardo

2015

Acta Ophthalmologica

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ABSTRACT.Purpose: To assess the impact of human crystalline lens opacification and yellowing, similar to that observed in patients with cataracts, on retinal vessel blood oxygen saturation measurements using custom manufactured soft contact lenses. Methods: Ten healthy, non-smoking individuals were enrolled for this study. All subjects underwent digital blood pressure measurements, assessment of noncontact intra-ocular pressure, pupil dilation and retinal vessel oximetry using dual-wavelength photography (Oximetry Module, Imedos Systems). To simulate lens changes, three different contact lenses were inserted, one to simulate opacities followed by two more lenses to simulate different levels of lens yellowing (Cantor & Nissel). Results: The measurements obtained showed an opposite change in arterial and venous oxygen saturation and optical density ratio across conditions, resulting in a statistically significant difference in arterial minus venous oxygen saturation value (p = 0.003). However, this difference was only significant for the 'opacity' condition but not for the 'yellowing' conditions. Conclusion: Lenticular changes such as cataracts can impact on spectrophotometric analysis in particular dual-wavelength retinal vessel oximetry. Hence, lenticular assessment and cataract grading should be considered when assessing elderly individuals and patient groups developing cataract earlier in life such as those suffering from diabetes mellitus.

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The effect of simulated cataract light scatter on retinal vessel oximetry

Cited by 16 publications

References 27 publications

The effect of vitreomacular and cataract surgery on oxygen saturation in retinal vessels

The effect of vitreomacular and cataract surgery on oxygen saturation in retinal vessels

Preoperative and postoperative measurements of retinal vessel oxygen saturation in patients with different grades of cataracts

The influence of simulated cataract on retinal vessel oximetry measurements

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