Effect of the pigment-free optical zone diameter of decorative tinted soft contact lenses on visual function.

1. JOURNAL CLUB
Arjun Sapkota
Final Year, B.Optometry
Maharajgunj medical Campus
KATHMANDU

2. Visual functions in
tinted soft contact lens

3. Effect of the pigment-free optical
zone diameter of decorative tinted
soft contact lenses on visual
function
Ji Won Jung,1,2 Sang Myung Kim,1 Sun Hyup Han,1 Eung Kweon Kim,1,3
Kyoung Yul Seo,1 Tae-im Kim

4. • 1 Department of Ophthalmology, The Institute of Vision Research,
Yonsei University College of Medicine,Seoul, South Korea
•
2 Department of Ophthalmology and Inha Vision Science Laboratory,
Inha University
School of Medicine, Incheon, South Korea
•
3 Corneal Dystrophy Research Institute, Severance Biomedical Science
Institute, and Brain Korea 21 Plus Project for Medical Science, Yonsei
University College of Medicine, Seoul, South Korea

5. Introduction
• Contact lenses are thin and curved disk that are rested directly on
the surface of the eye for vision correction
• Apart from vision correction, these lenses are also used as a sign
of fashion
• Now-a-days everyone is interested to wear contact lenses due to
the advances in optical technology, comfortability, easier to wear
and its effectiveness

6. • Coloured contact lenses are the most stylish update of existing
version that allows the instant transformation of the entire
appearance of the wearer by changing the colour of the pupil
• High quality coloured contact lenses are manufactured by
renowned contact lenses brands like Bausch and Lomb,
Freshlook and Freshkon

7. Parameters
• Total Diameter- 14.00 mm to 14.50 mm
• Optic Zone diameter
6.00 mm
Base curve- median(8.60)mm

8. • The global market for contact lenses - 4.5% per annum.1
• Approx. 1/3rd of all contact lens wearers use decorative
tinted soft contact lenses.1 2
• A decorative tinted soft contact lens contains a central
pigment-free optical zone and a peripheral pigment-tinted
area
1 The 2010 Study of the Intern’l Market for Contact Lenses conducted by
Multi-sponsor Surveys International LLC. http://multisponsorinternational.com
(accessed 9 Aug 2014)
2 Rah MJ, Schafer J, Zhang L, et al. A meta-analysis of studies on cosmetically tinted soft
contact lenses. Clin Ophthalmol 2013;7:2037–42

9.  Has a cosmetic effect of making the corneal diameter appear
larger and accentuating the iris color
 Demographical data- that the population using such cosmetic
contact lenses primarily consists of young
females.3
 Mostly use these lenses mainly for cosmetic purposes
3 .Singh S, Satani D, Patel A, et al. Colored cosmetic contact lenses: an unsafe
trend in the younger generation. Cornea 2012;31:777–9.

10. • Most of the lenses are obtained from an over-the-counter source,
an unlicensed optical shop.3 4
• Especially, the surface pigments on poorly manufactured
decorative tinted lenses can increase surface roughness, which
might promote bacterial adhesion and infection.5
3. Singh S, Satani D, Patel A, et al. Colored cosmetic contact lenses: an unsafe trend In the
younger generation. Cornea 2012;31:777–9.
4. Steinemann TL, Pinninti U, Szczotka LB, et al. Ocular complications associated with the use
of cosmetic contact lenses from unlicensed vendors. Eye Contact Lens
2003;29:196–200.
5.Chan KY, Cho P, Boost M. Microbial adherence to cosmetic contact lenses. Cont
Lens Anterior Eye 2014;37:267–72.

11. • Lenses were previously reported to have adverse effects on
visual performance, including visual field constriction, night
vision disturbances and decline in contrast sensitivity.6 7
• Tinted lens wearers sometimes complain about blurred vision
even despite preserved visual acuity
6 Spraul CW, Roth HJ, Gäckle H, et al. Influence of special-effect contact lenses (crazy
lenses) on visual function. CLAO J 1998;24:29–32.
7 Ozkagnici A, Zengin N, Kamiş O, et al. Do daily wear opaquely tinted hydrogel soft
contact lenses affect contrast sensitivity function at one meter? Eye Contact Lens
2003;29:48–9.

12. • Several methods to evaluate visual quality using
aberrometer and functional visual acuity (FVA) instrument
have been introduced and studies of tinted lenses have
been reported.8–11
• Market research- that many tinted contact lenses with
varying sizes of the central pigment-free optical zone and
users preferred lenses with smaller central pigment-free
zone and larger peripheral pigment-tinted zone for
dramatic effect on iris color or shape
8 Hiraoka T, Ishii Y, Okamoto F, et al. Influence of cosmetically tinted soft contact
lenses on higher-order wavefront aberrations and visual performance. Graefes Arch
Clin Exp Ophthalmol 2009;247:225–33.
9 Takabayashi N, Hiraoka T, Kiuchi T, et al. Influence of decorative lenses on
higher-order wavefront aberrations. Jpn J Ophthalmol 2013;57:335–40.
10 Watanabe K, Kaido M, Ishida R, et al. The effect of tinted soft contact lens wear on
functional visual acuity and higher-order aberrations. Contact Lens Anterior Eye
2014;37:203–8.
11 Ortiz C, Jiménez R. Optical quality and vision with iris-coloring soft contact lenses.
Optom Vis Sci 2014;91:564–9.

13. • To evaluate the effects of the different pigment free optical
zone diameters on visual function
• To investigate the mechanism underlying the decreased
visual quality after wearing the tinted lenses
Objective of the study

14. MATERIALS AND METHODS
• Prospective study
• 30 eyes from 30 normal subjects
• Best-corrected visual acuity (BCVA) of ≥20/20
• No any history of ocular disease, previous ocular surgery
or systemic disorders that may affect the VA

15. • Prescreening slit-lamp examination was performed
on all eyes
- to confirm absence of ocular pathologies
• Informed consent for participation in the study was
obtained after the study protocol had been fully
explained

16. • Tinted SCLS of 3 different central pigment-free optical
zone diameter of 4, 5 and 6 mm were manufactured and
used in this study
• Peripheral area of the lenses consisted of dark-coloured
pigment-tinted zone based on a modification of daily-
wear tinted lens (eyelike Callamatch II, Koryo Eyetech Co, Seoul,
Korea)

17. • The total diameter (TD )- 14.0 mm
Base Curve - 8.6 mm
• The lens material- modified polymacon with a water content of
40%
• The characteristics of the clear lens (eyeLIKe Shine, Koryo Eyetech Co)
were the same as those of the tinted soft contact lens

18. • Slit-lamp examination was performed on all subjects
• To confirm the contact lenses fitted comfortably in the centre
both vertically and horizontally and repositioned within 0.5–1.0
mm during a single blink before measurement in all subjects

19. • BCVA, ocular aberrations, modulation transfer function (MTF),
the Strehl ratio & CS were evaluated after wearing the clear &
decorative tinted soft contact lenses with various diameters of
pigment-free optical zone
• The lenses were worn in a random order with at least 1 hr of
rest between wearing lenses, which allowed for full equilibrium
on the eye

20. • Each lens was worn for at least 30 mins prior to any
measurements
• Ocular aberrations measured by iTrace (Tracey Technologies,
Houston, Texas, USA; software V.4.1.0) through a natural pupil
without using dilating drugs at a fixed entrance scan size of 4.0
mm
• Measurements were repeated at least 3 times and the best
scan was chosen for the final analysis

21. • The data were considered valid after confirming that there
were < 9 rejected points in the measurement
• The iTrace automatically displayed ocular aberration
measurements in root mean square (RMS) values

22. • MTF and Strehl ratio were obtained from the ray-tracing
aberrometer for a 4 mm pupil size
• Strehl ratio is the ratio of peak focal intensity in
aberration versus an ideal point spread function,12
and it provides general information about the eye’s optical
quality
• A value of 1 corresponds to a perfect zero-aberration
optical system

23. • Contrast sensitivity measured by Optec 6500 test system
(Stereo Optical Co, Chicago, Illinois, USA) at five spatial frequencies
(1.5, 3, 6, 12 and 18 cycles/degree (cpd) under photopic (luminance
value of 85candelas/square metre (cd/m2)) and mesopic conditions
(target luminance value of 3 cd/m2) with or without glare
• Intense illumination of 12 white light emitting diodes around the
field (10 lx for photopic; 1 lx for mesopic) was used as a source
of glare

24. • Ocular aberration and contrast sensitivity scores were
compared using repeated-measures analysis of variance
(ANOVA) incorporating, where necessary, a Greenhouse–
Geisser correction for non-sphericity
• If significant differences were observed with the ANOVA test,
paired t test was performed to determine significant differences
among the four conditions

25. • Because of multiple comparisons, an adjusted p value was
used after Bonferroni correction, and significance was defined
as a probability value of <0.05
• The blocked pupil covered by the tinted area of lens was
measured by subtracting the pigment-free optical zone
diameter from pupil size

26. • The pupil size was measured using the iTrace in mesopic
condition
• Correlation between the higher-order aberrations (HOAs)
and the blocked pupil was analysed using linear
regression analysis and Pearson’s correlation

27. Result
• A total of 30 eyes of 30 subjects (11 men and 19 women) were
included
• The mean age of the subjects in this study was 28.8
±3.5 years (range, 21–37 years)
• The mean BCVA was 0.00 logMAR and mean spherical
equivalent was −1.2±1.7 D (range, −6.0 to 0.0 dioptres)

28. • The mean mesopic pupil size, measured using the iTrace, was
6.4±0.5 mm
• BCVA was 0.00±0.00 logMAR for the clear lens, 0.01±0.02,
0.01±0.03 and 0.04±0.04 logMAR for the tinted contact lenses
with 6, 5 and 4 mm pigment-free optical zone, respectively
(p<0.001, repeated-measures ANOVA)

29. • Using the paired t test, no significance for difference in
BCVA between the clear lens and 6 or 5 mm tinted lenses
was observed
• However, after wearing the lens with 4 mm optical zone,
the BCVA decreased significantly (p<0.001)

30. Effects of the pigment-free optical zone diameter of tinted soft
contact lenses on ocular optical quality

31. • With decrease in pigment-free optical zone diameter, ocular
aberrations except trefoil aberration increased significantly (all
p<0.050)
• The mean RMS values of the total HOAs were 0.238±0.112 for
the clear lens, 0.298±0.123 mm for 6 mm, 0.535±0.197 mm for
5 mm and 0.600±0.245 mm for 4 mm pigment-free optical zone
lens (p<0.001, repeated measures ANOVA)

32. • No significant difference between clear lens and 6 mm optical
zone diameter lens for all ocular aberrations
• Total HOAs, coma aberration and secondary astigmatism
showed significant difference between clear lens and 5
or 4 mm sized optical zone lenses (adjusted p<0.050 after
Bonferroni correction, paired t test)

33. • Spherical aberration and trefoil aberration showed significant
difference between clear lens and 4 mm sized optical zone lens
(adjusted p<0.050)
• The results of the Strehl ratio revealed poorer optical quality for
both 5 and 4 mm pigment-free optical zone lens, compared
with clear lens (both adjusted p=0.002).

34. • The entire ocular MTF was significantly different,
corresponding to the decreased pigment-free optical zone
diameter at all spatial frequencies (p<0.001, repeated-
measures ANOVA)

36. Correlation between ocular aberrations and the blocked pupil
covered by the tinted area of the lenses
• Showed a strong correlation between the blocked pupil
covered by the tinted area of the lens and ocular
aberration including total HOAs (r=0.435, p<0.001,
Pearson’s correlation coefficient), coma aberration
(r=0.266, p=0.027) and
secondary astigmatism (r=0.316, p=0.008)
• Linear regression analysis showed that total HOAs, coma
aberration and secondary astigmatism were significantly
increased, consistent with the increased pupil diameter
covered by the tinted section of decorative lens

38. Effects of the pigment-free optical zone diameter of decorative
tinted soft contact lenses on contrast sensitivity
• As the pigment-free optical zone diameter decreased, contrast
sensitivity also decreased significantly under photopic condition
without stimuli of glare at spatial frequency 12 cpd
(p=0.027,repeated-measures ANOVA)

39. • Under mesopic conditions, contrast sensitivity significantly
decreased at spatial frequency of 3 and 6 cpd with or
without glare stimulation (all p<0.05, repeated measures
ANOVA)
• Under these conditions, only the difference between the
clear lens and 5 or 4 mm sized optical zone lenses
showed statistical significance (adjusted p<0.05 after
Bonferroni correction, paired t test

41. DISCUSSION
• The changes in visual functions after wearing tinted soft
contact lenses with different diameters for pigment free
optical zones were investigated
• Compared with the clear lens with the same diopter, the
tinted soft contact lens with the smallest pigment free
optical zone (4 mm) showed a significant reduction in
BCVA.

42. • Some studies recently demonstrated increased aberration
& altered visual function after wearing tinted contact lenses,
but used tinted lenses with different optical zone diameters
& did not adequately address the varying effects of different
diameters of the pigment-free zones.8–11
• The deteriorating effects of the tinted lens on visual function
in relation to the diameter of central pigment-free optical
zone were investigated
• In the current study, ocular aberrations except trefoil
increased significantly, corresponding to the decreased
pigment-free optical
zone diameter.

43. • Results showed that total HOAs, coma aberration & secondary
astigmatism showed a significant difference between clear lens
and 4 or 5 mm optical zone lenses
• Spherical aberration and trefoil showed a significant difference
between clear lens and 4 mm optical zone lens.
• However the difference in ocular aberrations between the
clear and 6 mm tinted lens was not significant.

44. • Hiraoka et al8- tinted contact lenses increase ocular HOAs
and worsen contrast sensitivity
• Used a tinted soft lens with a central clear zone of 5.4 mm
& reported the changes in ocular HOAs for a 4 mm pupil
suggested several possible explanations
• 1st, corneal change/unstable lens surface due to the
differences of water content or physical property between
clear & tinted area could have caused the ocular aberration
in eyes wearing tinted lens

45. • The relevance of surface roughness of the tinted area of the
lenses had been reported in other studies,5 13
• 2nd, conside a proper lens movement of about 0.5–1 mm on a
blink, the center of tinted lens was unlikely to coincide with the
corneal center all the time; the tinted area covering the pupil
might have obscured the vision
• Present study-ocular aberration is more aggravated by a smaller
optical zone diameter lens, which agrees with the second reason

46. • Takabayashi et al9 described the influence of decorative
lenses on HOAs in different pupil sizes using two tinted
lenses with 6.2 and 8.7 mm central clear zones
• Compared with those of the clear lenses, HOAs of both
tinted
lens groups increased significantly
• No difference in HOAs between the two tinted lenses

47. • Poorly fitting decorative lenses also had larger RMS values of
the total HOAs than did appropriately fitting clear lenses
• Explained that the increase in HOAs including coma-like
aberrations was caused by the mismatched optical centers
despite the appropriate fit and minimal movement (<1 mm) on
blinking

48. • Watanabe et al10 assessed the differences of FVA &
HOAs in relation to tinted & clear soft contact lens wear
• Used a tinted lens with 6.2 mm central clear zone &
showed the decline of FVA and the increase of coma-like
aberrations
• Suggested -minute changes in lens position during natural
blinks might have increased the HOAs causing a
decrease in FVA, according to the pupil size

49. • Previously-researchers believed that pupil size influenced the
visual performance after wearing tinted lens,8–11 the results failed
to reveal direct correlation between HOAs and pupil size
• In this study, used the blocked pupil as the indicator & showed a
positive correlation between increased ocular aberrations,
including total HOAs, coma aberration, 20 astigmatism,& the
blocked pupil
• Because of natural displacement of the lens by blinking-a
transient and partial mismatch between the centres of the lens
and the cornea, causing disruption in the light transmittance

50. • In addition, factors such as light scattering at the border
between optical and tinted areas and rugged surface of
the lens likely contributed to the increase in ocular
aberration
• Such factors became more significant as the optical zone
diameter was decreased

51. • Also, the results of the Strehl ratio and entire ocular MTF
revealed poorer optical quality corresponding to the decreased
optical zone diameter
• Small optical zones of tinted lenses could have induced ocular
aberrations which compromise optical qualities significantly.12 14
• Demonstrated- CS significantly diminished under photopic and
mesopic conditions as the pigment-free optical zone diameter
decreased

52. • Reduced contrast sensitivity in response to tinted lenses
was considered as the result of increased HOAs induced
by the tinted contact lenses.8
• Although clear contact lenses might decrease contrast
sensitivity due to residual astigmatism,15 spherical
aberration,16 contact lens deposits17 and corneal
oedema,18

53. • This study showed- the tinted soft contact lens exhibited more
serious reduction in contrast sensitivity,A/C to the pigment-free
optical zone diameter
• So, the reduction in contrast sensitivity after wearing tinted
lenses might have been also caused by induced HOA and
altered light transmittance by the blocked pupil.

54. • Although this study was limited by its small size, it was
revealed that, as the pigment-free optical zone diameter
decreased,
• the tinted soft contact lens significantly increased ocular
aberrations and decreased optical quality and contrast
sensitivity

55. • Optical effect of partially covered pupil might play a role in
the increased ocular aberrations after wearing tinted
lenses
• Based on these results, consumers using tinted contact
lenses should be informed of potential side effects on
visual function related to the small pigment-free optical
zone of the lens

56. • In addition,no statistically significant difference in aberration,
corrected vision and contrast sensitivity between clear lens and
6 mm optical zone diameter lens
• A minimum diameter of 6 mm pigment-free optical zone
should be established and regulated as a standard for
decorative tinted lenses approval

57. Conclusion
• Decorative tinted contact lenses significantly increases ocular
aberrations and decreases optical quality & contrast sensitivity,
as the pigment free optical zone diameter decreased
• Finally, tinted lenses users should be informed about the possible
disturbance in visual function

58. Thank You