Effect of the color of the intraocular lens on optical and visual quality

[Functional results of spectral correction of vision]

PURPOSE

To study the data of monocular and binocular multifocal electroretinogram (mfERG), flash visual evoked potential (f-VEP), spatial contrast sensitivity (SCS) with and without yellow filters in healthy elderly people.

MATERIAL AND METHODS

The study included 16 people (8 male and 8 female) with average age of 51.63±4.7 years. Their visual acuity was 0.5±0.35 without correction and 1.0 with correction. For spectral correction, we used Y1 color filters (CF) (analogue of SN60AT) from the «Lornet-M vision spectral correction kit» set with 80% light transmission and wave cut-off of 460 nm. Patients had mfERG recordings performed monocularly and binocularly, f-VEP monocularly, and their spatial contrast sensitivity (SCS) was measured (Astroinform SPE, Russia). The data acquired before and after applying CF was compared.

RESULTS

The data of SCS with light filter was slightly higher at medium and high spatial frequencies (SF): for the right eye on medium SF of 43.8 and 41.8 dB (p≤0.735), 41.5 and 39.8 dB (p≤0.061) for the left eye. The increase of mfERG P1 latency monocularly after application of CF in the R1 ring area was 3.0 ms (40.8-43.8ms) for the right eye (p≤0.05) and 0.9 ms for the left eye (43.7-44.5ms) (p≤0.326). The trend remained for simultaneous mfERG.

CONCLUSION

The influence of yellow filters on spectral vision correction can be manifested in inconsistency of SCS, f-VEP, monocular and binocular mfERG readings. Statistically significant differences in healthy individuals of 5th-6th age decades manifest as elongation of the latency of mfERG peaks.

Visual acuity and color discrimination in patients with cataracts

Color vision tests can give information about pathological changes in eye structures. The purpose of our research was to study the color vision sensitivity and visual acuity changes before and after cataract surgery. We used a saturated Farnsworth D15 color vision arrangement test to check color sensitivity changes in confusion line directions. The test is easily perceptible (essential to eldery patients), and it is possible to check color sensitivity changes in tritan, protan, and deutan confusion line directions. The results were analyzed in several ways: by summing the color differences between adjacent caps according to Bowman and averaging the color difference vectors according to Vingrys and King-Smith. Color difference vectors determine the severity (or confusion), selectivity (or scatter), and type of color deficiency to the presented cap arrangements. In the least squares regression method, the error type is determined by the angular proximity of the best-fit line to known confusion axes representing protan, deutan, tritan, or unspecified color defects. All three tests showed that cataract-induced lens opacity significantly decreases a patient's chromatic resolution in the visible light region. Before the cataract surgery, the D15 test stimulus arrangement sequence showed similarities with tritan color deficiency.

Occlusion for stimulus deprivation amblyopia

BACKGROUND

Stimulus deprivation amblyopia (SDA) develops due to an obstruction to the passage of light secondary to a condition such as cataract. The obstruction prevents formation of a clear image on the retina. SDA can be resistant to treatment, leading to poor visual prognosis. SDA probably constitutes less than 3% of all amblyopia cases, although precise estimates of prevalence are unknown. In high-income countries, most people present under the age of one year; in low- to middle-income countries, people are likely to be older at the time of presentation. The mainstay of treatment is correction of the obstruction (e.g., removal of the cataract) and then occlusion of the better-seeing eye, but regimens vary, can be difficult to execute, and traditionally are believed to lead to disappointing results.

OBJECTIVES

To evaluate the effectiveness of occlusion therapy for SDA in an attempt to establish realistic treatment outcomes and to examine evidence of any dose-response effect and assess the effect of the duration, severity, and causative factor on the size and direction of the treatment effect.

SEARCH METHODS

We searched CENTRAL (2018, Issue 12), which contains the Cochrane Eyes and Vision Trials Register; Ovid MEDLINE; Embase.com; and five other databases. We used no date or language restrictions in the electronic searches. We last searched the databases on 12 December 2018.

SELECTION CRITERIA

We planned to include randomized controlled trials (RCTs) and controlled clinical trials of participants with unilateral SDA with visual acuity worse than 0.2 LogMAR or equivalent. We specified no restrictions for inclusion based upon age, gender, ethnicity, comorbidities, medication use, or the number of participants.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology.

MAIN RESULTS

We identified no trials that met the inclusion criteria specified in the protocol for this review.

AUTHORS' CONCLUSIONS

We found no evidence from RCTs or quasi-randomized trials on the effectiveness of any treatment for SDA. RCTs are needed in order to evaluate the safety and effectiveness of occlusion, duration of treatment, level of vision that can be realistically achieved, effects of age at onset and magnitude of visual defect, optimum occlusion regimen, and factors associated with satisfactory and unsatisfactory outcomes with the use of various interventions for SDA.

Effect on contrast sensitivity after clear, yellow and orange intraocular lens implantation

The objective of this study is to evaluate contrast sensitivity function (CSF) after clear, yellow- and orange-tinted intraocular lens (IOL) implantation. This was a prospective randomized study of 98 patients with senile cataract for a period of 6 months from day 1 of August 2014 to day 31 of January 2015. After phacoemulsification, 33 patients were implanted with clear IOLs (AcrySof UV-filtering IOL, SA60AT), 32 patients were implanted with yellow coloured IOLs (AcrySof Natural blue-light-attenuating and UV-filtering IOL, SN60AT with IMPRUV(®) filter) and 33 patients were implanted with orange-tinted blue-filtering IOLs (PC440Y Optech). After 1 month, monocular CSF was done under photopic (85 cd/m(2)) and mesopic (3 cd/m(2)) illumination condition with CSV-1000 test. The best corrected visual acuity (BCVA) after 1 month was 0.021 ± 0.058 logMAR for clear lens, 0.022 ± 0.059 logMAR for yellow lens and 0.019 ± 0.065 logMAR for orange lens (p = 0.989). Uniocular average photopic contrast sensitivity was 1.36 ± 0.19, 1.43 ± 0.18 and 1.46 ± 0.15 log units for clear lens, yellow lens and orange lens, respectively (statistically not significant; p = 0.076). Average mesopic contrast sensitivity was 1.02 ± 0.21 log units for clear lens, 1.00 ± 0.17 log units for yellow lens and 0.99 ± 0.15 log units for orange lens (statistically not significant; p = 0.771). Yellow or orange coloured blue-filtering IOLs are comparable to clear IOLs in terms of photopic and mesopic contrast sensitivity.