Indian Journal of Ophthalmology

ORIGINAL ARTICLE
Year
: 2018  |  Volume : 66  |  Issue : 5  |  Page : 653--656

Correlation between dry eye and refractive error in Saudi young adults using noninvasive Keratograph 4


Rania M Fahmy1, Amal Aldarwesh2,  
1 Department of Optometry and Vision Sciences, King Saud University, Riyadh, Saudi Arabia; Department of Ophthalmology, Faculty of Medicine, Cairo University, Giza, Egypt
2 Department of Optometry and Vision Sciences, King Saud University, Riyadh, Saudi Arabia

Correspondence Address:
Prof. Rania M Fahmy
Department of Optometry and Visual Sciences, King Saud University, P.O. Box 89885, Riyadh 11692

Abstract

Purpose: The purpose is to study the correlation between dry eye and refractive errors in young adults using noninvasive Keratograph. Methods: In this cross sectional study, a total of 126 participants in the age range of 19–25 years and who were free of ocular surface disease, were recruited from King Saud University Campus. Refraction was defined by the spherical equivalent (SE) as the following: 49 emmetropic eyes (±0.50 SE), 48 myopic eyes (≤−0.75 SE and above), and 31 hyperopic eyes (>+0.75 SE). All participants underwent full ophthalmic examinations assessing their refractive status and dryness level including noninvasive breakup time (NIBUT) and tear meniscus height using Keratograph 4. Results: The prevalence of dry eye was 24.6%, 36.5%, and 17.4% in emmetropes, myopes, and hypermetropes, respectively. NIBUT has a negative correlation with hyperopia and a positive correlation with myopia with a significant reduction in the average NIBUT in myopes and hypermetropes in comparison to emmetropes. Conclusion: The current results succeeded to demonstrate a correlation between refractive errors and dryness level.



How to cite this article:
Fahmy RM, Aldarwesh A. Correlation between dry eye and refractive error in Saudi young adults using noninvasive Keratograph 4.Indian J Ophthalmol 2018;66:653-656


How to cite this URL:
Fahmy RM, Aldarwesh A. Correlation between dry eye and refractive error in Saudi young adults using noninvasive Keratograph 4. Indian J Ophthalmol [serial online] 2018 [cited 2024 Mar 29 ];66:653-656
Available from: https://journals.lww.com/ijo/pages/default.aspx/text.asp?2018/66/5/653/230658


Full Text



Dry eye syndrome (DES) is a common disorder that eye care providers encounter on a daily basis in which it accounts for 25% of patients' visits.[1] The report of the epidemiology subcommittee of the 2007 International Dry Eye Workshop (DEWS) revealed that the prevalence of dry eye lies somewhere in the range of 5%–30% in the population aged 50 years and older.[2] Studies have found that DES affects more women than men, especially after menopause.[3],[4],[5],[6]

It is characterized by discomfort symptoms such as burning, tearing, foreign body sensation, and ocular fatigue. Moreover, chronic dry eye is associated with inflammatory ocular surface and damage. The change in tear film osmolarity is also another outcome of DES as stated in 2007 definition of DES by DEWS. Recently, the Tear Film and Ocular Surface Society DEWS II has revised the definition as follows:

“Dry eye is a multifactorial disease of the ocular surface characterized by a loss of homeostasis of the tear film, and accompanied by ocular symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities play etiological roles.”[7]

Several risk factors have been reported to increase the risk of DES such as the is the long-term wear of contact lens and refractive surgery such as laser-assisted in situ keratomileusis or photorefractive keratectomy (LASIK).[8],[9] Questionnaire-based studies have shown that contact lens wearers have symptomatic DES than noncontact lens wearer.[10],[11],[12] Data obtained from self-reported questionnaires lack the connection between the rate and severity of DES and the status of the clinical refractive status. On the other hand, a common finding between these studies is that approximately 50% of contact lens wearer reported dry eye.[10],[11],[12],[13],[14] Interestingly, spectacle lens and contact lens wearers were twice and 12 times, respectively, more likely than emmetropes to report DES.[15] Symptomatic dry eye could be diagnosed in the clinic through examining the tear film stability. This could be achieved through measuring the tear breakup time using newly developed apparatus such as the Keratograph. Diagnostic tests of DES such as tear breakup time, Schirmer's test, corneal fluorescein staining, the rose bengal staining, and tear lysozyme and lactoferrin test are all traditional methods that have pros and cons. Hence, the noninvasive diagnostic test is always preferred by both the clinicians and the patients; the Keratograph is a promising noninvasive method that has several advantages over other methods. For instance, Keratograph 4 has been reported to identify significantly lower NIBUT values than the Tearscope.[16] A recent article by Abdelfattah et al.[17] demonstrated the advantage of using Keratograph compared to a traditional fluorescein-based method in measuring the tear film dynamics. Studies have also shown that Keratograph gives more consistent results over traditional methods using fluorescein staining.[18],[19] One study by Srinivasan et al.[20] found that Keratograph 4 is useful clinically to image the meibomian gland structure and detect changes in symptomatic dry eye participants. This is in agreement with Abdelfattah et al.,[17] who used Keratograph 5 to determine tear meniscus height (TMH) and noninvasive breakup time (NIBUT) values as well as the glandular density and glandular atrophy in DES and Sjögren syndrome. This study aims to add new information about the asymptomatic DES in young adult females by examining the correlation between refractive errors and objective measurements of NITBUT using Keratograph 4.

 Methods



The study was approved by the Ethical Committee at College of Applied Medical Sciences, King Saud University, and informed consent followed the tenets of the Declaration of Helsinki.

Participants with best-corrected visual acuity of 6/9 were eligible for this study. The exclusion criteria included those participants with ocular allergic disease, keratitis, ocular surface disease, contact lens wear, glaucoma, previous ocular surgery or injury, or systemic or ocular treatment. In this cross sectional study, a total of 126 participants in the age range of 19–25 years and who were free of ocular surface disease, were recruited from King Saud University Campus. Refraction was defined by the spherical equivalent (SE) as the following: 49 emmetropic eyes (±0.50 SE), 48 myopic eyes (≤−0.75 SE and above), and 31 hyperopic eyes (>+0.75 SE).

All participants underwent full ophthalmic examinations starting with the NIBUT and TMH using Keratograph 4, to avoid the disturbance of tear film stability. This was followed by measurement of refractive error using auto refractometer, visual acuity by Snellen chart, slit-lamp examination, Goldmann applanation tonometry, and the biomicroscopic funduscopy (90D lens).

Keratograph 4 evaluation

All participants underwent imaging with Keratograph 4 (Oculus GmbH, Wetzlar, Germany), a noncontact device that combines keratometric and topographic measuring methods in a single unit. The principle of noninvasive Keratograph 4 tear breakup time (NIKBUT) measurement has been described previously.[19],[20] In summary, a single examiner measured the TBUT three times at 5-minute interval using the Oculus NIKBUT tool. The measurement of the corneal surface was carried out through a system of rings which are reflected at the cornea with more than 1000 measurement points per ring, resulting in thousands of analyzed data points per frame. A video recording of the ocular surface begins with real-time detection and localization of breaks in the tear film. The video recording lasts up to a maximum of 25 s or until the patient's next blink. The average NIKBUT is the parameter of interest in the current study. Participants with breakup time ≤10 s were considered to have dryness. In general, TBUT >10 s is thought to be normal, 5–10 s indicates mild-to-moderate dryness, and <5 s is considered severe dryness.[22],[23],[24] This cutoff point was also chosen based on the reported agreement between the traditional fluorescein-tear breakup time (FTBUT) and NIBUT.[17],[25] Patients were also assessed using a dryness grade 0–2 generated by the Keratograph in which Grade 0 indicates normal finding, Grade 1 reflects mild-to-moderate dryness, and Grade 2 indicates severe dryness. The same examiner carried out the TMH measurements using Oculus Keratograph 4 according to the method described by Santodomingo-Rubido et al.;[26] TMH is divided into three grades from Grade 0 to Grade 2 indicating the normal value (>0.2 mm), the critical value (~0.2 mm), and the dry eye (<0.2 mm).

Statistical analysis

All statistical analysis was performed utilizing GraphPad Prism Software v. 7. For Mac, (GraphPad Software, La Jolla California USA, www.graphpad.com). The test was considered significant when P ≤ 0.5. Analysis of variance was used to compare NIBUT and TMH between the groups. Linear regression was used to investigate the association between NIBUT, TMH, and refractive errors.

 Results



Tear meniscus height and noninvasive Keratograph 4 tear breakup time

The Oculus Keratograph 4 recorded no statistical difference in automated TMH values between the studied groups [Figure 1]a and [Figure 1]b. On the other hand, the tear breakup time in seconds as measured by Keratograph 4 (NIKBUT) showed significant shorter time in eyes of myopic and hyperopic individuals compared to emmetropia [9.7: 9.4: 12.2 s, respectively, P ≤ 0.5; [Figure 2]a and [Figure 2]b. The correlation between refractive errors, TMH, and NIKBUT is displayed in [Table 1]. A weak positive relationship was found between NIKBUT and myopia (r = 0.295) while a significant inverse relationship was found between NIKBUT and hyperopes (r = −0.405). Based on the NIKBUT values, the participants were categorized into having no dryness (n = 27), mild-to-moderate dryness (n = 80), or severe dryness (n = 19) in relation to their refractive errors as shown in [Figure 3]. Among the participants in this study, no myopes were found to be free of dryness while they constitute the majority in mild-to-moderate dryness class (51.3%, n = 41). Individuals with hyperopia were the majority of the severe dryness class (63.2%, n = 12).{Figure 1}{Figure 2}{Figure 3}{Table 1}

 Discussion



DES is a common disorder that affects a significant percentage of the populations worldwide. The influence of female sex hormones on the tear film stability makes females more vulnerable to DES and reports more symptoms than males.[4] Studies have shown that postmenopausal women are more affected by DES due to lack of hormonal support.[21],[22],[23] This limits the focus of dry eye research to individuals over the age of 50 years in both genders.[3],[5],[27] The rate of dry eye in young adults is not well known although the visual tasks that younger adults are taking nowadays make them more vulnerable to DES. Video games, computers, and different digital devices as well as contact lenses are all contributing to the development of DES in younger patients.[28],[29],[30],[31] Studies have revealed that the overuse of smartphones is associated with increased risk of DES in children.[32],[33],[34] Moreover, very few studies have shown evidence that refractive errors could contribute to the development of DES in young individuals.[35],[36] The aim of this study was to examine the prevalence of DES among young Saudi females in relation to the refraction error. Relying on NIBUT and TMH, the current study shows that both myopic and hyperopic individuals have significantly reduced NIBUT values of <10 s which is indicative of dryness in 61% of the participants although the TMH values were in normal range. This is in agreement with findings from Wang et al.,[36] who reported high prevalence of DES among myopic teenagers using Keratograph 5M. In another study, Lin et al.[27] found a correlation between the breakup time and meibomian gland disease. Interestingly, undercorrection of refractive error and female gender was found to significantly associate with dry eye symptoms despite a near normal tear film breakup time.[37] This supports the notion that refractive error could be linked to DES as found in the current study. Unfortunately, the mechanism of refractive error inducing eye dryness is unknown. The cross-sectional design of this study allowed screening of dryness among people with refractive error, but it would have been interesting to find the relation in terms of causality. As stated earlier, individuals with refractive error are among those with a higher rate of contact lens and spectacle use as well as the reported rate of dryness.[15] Clinically, the changes in the anterior corneal surface as the eyeball elongates in myopia may contribute to increase the likelihood of developing dryness.[35],[37],[38],[39] In conclusion, noninvasive ocular surface examinations using Keratograph 4 showed a low NIBUT in healthy participants with refractive error which could be indicative of DES. Although it would have been interesting to examine the relationship between the refractive error and development of DES, the present data need to be supported by a further study of larger population.

 Conclusion



Results succeeded to demonstrate a correlation between refractive errors and dryness level.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1O'Brien PD, Collum LM. Dry eye: Diagnosis and current treatment strategies. Curr Allergy Asthma Rep 2004;4:314-9.
2The definition and classification of dry eye disease: Report of the definition and classification subcommittee of the international dry eye workShop (2007). Ocul Surf 2007;5:75-92.
3Moss SE, Klein R, Klein BE. Prevalence of and risk factors for dry eye syndrome. Arch Ophthalmol 2000;118:1264-8.
4Rapoport Y, Singer JM, Ling JD, Gregory A, Kohanim S. A comprehensive review of sex disparities in symptoms, pathophysiology, and epidemiology of dry eye syndrome. Semin Ophthalmol 2016;31:325-36.
5Schaumberg DA, Sullivan DA, Buring JE, Dana MR. Prevalence of dry eye syndrome among US women. Am J Ophthalmol 2003;136:318-26.
6Schaumberg DA, Sullivan DA, Dana MR. Epidemiology of dry eye syndrome. Adv Exp Med Biol 2002;506:989-98.
7Craig JP, Nichols KK, Akpek EK, Caffery B, Dua HS, Joo CK, et al. TFOS DEWS II definition and classification report. Ocul Surf 2017;15:276-83.
8Ang RT, Dartt DA, Tsubota K. Dry eye after refractive surgery. Curr Opin Ophthalmol 2001;12:318-22.
9Donnenfeld ED, Ehrenhaus M, Solomon R, Mazurek J, Rozell JC, Perry HD, et al. Effect of hinge width on corneal sensation and dry eye after laser in situ keratomileusis. J Cataract Refract Surg 2004;30:790-7.
10Begley CG, Chalmers RL, Mitchell GL, Nichols KK, Caffery B, Simpson T, et al. Characterization of ocular surface symptoms from optometric practices in North America. Cornea 2001;20:610-8.
11Doughty MJ, Fonn D, Richter D, Simpson T, Caffery B, Gordon K, et al. Apatient questionnaire approach to estimating the prevalence of dry eye symptoms in patients presenting to optometric practices across Canada. Optom Vis Sci 1997;74:624-31.
12Guillon M, Cooper P, Maïssa C, Girard-Claudon K. Dry eye symptomatology of contact lens wearers and nonwearers. Adv Exp Med Biol 2002;506:945-9.
13Brennan NA, Efron N. Symptomatology of HEMA contact lens wear. Optom Vis Sci 1989;66:834-8.
14McMonnies CW. Key questions in a dry eye history. J Am Optom Assoc 1986;57:512-7.
15Nichols JJ, Ziegler C, Mitchell GL, Nichols KK. Self-reported dry eye disease across refractive modalities. Invest Ophthalmol Vis Sci 2005;46:1911-4.
16Best N, Drury L, Wolffsohn JS. Clinical evaluation of the oculus keratograph. Cont Lens Anterior Eye 2012;35:171-4.
17Abdelfattah NS, Dastiridou A, Sadda SR, Lee OL. Noninvasive imaging of tear film dynamics in eyes with ocular surface disease. Cornea 2015;34 Suppl 10:S48-52.
18Cox SM, Nichols KK, Nichols JJ. Agreement between automated and traditional measures of tear film breakup. Optom Vis Sci 2015;92:e257-63.
19Srinivasan S, Menzies K, Sorbara L, Jones L. Infrared imaging of meibomian gland structure using a novel keratograph. Optom Vis Sci 2012;89:788-94.
20Fuller DG, Potts K, Kim J. Noninvasive tear breakup times and ocular surface disease. Optom Vis Sci 2013;90:1086-91.
21Jiang Y, Ye H, Xu J, Lu Y. Noninvasive keratograph assessment of tear film break-up time and location in patients with age-related cataracts and dry eye syndrome. J Int Med Res 2014;42:494-502.
22Lee JH, Kee CW. The significance of tear film break-up time in the diagnosis of dry eye syndrome. Korean J Ophthalmol 1988;2:69-71.
23Kallarackal GU, Ansari EA, Amos N, Martin JC, Lane C, Camilleri JP, et al. Acomparative study to assess the clinical use of fluorescein meniscus time (FMT) with tear break up time (TBUT) and schirmer's tests (ST) in the diagnosis of dry eyes. Eye (Lond) 2002;16:594-600.
24Dibajnia P, Mohammadinia M, Moghadasin M, Amiri MA. Tear film break-up time in bipolar disorder. Iran J Psychiatry 2012;7:191-3.
25Lee R, Yeo S, Aung HT, Tong L. Agreement of noninvasive tear break-up time measurement between tomey RT-7000 auto refractor-keratometer and oculus keratograph 5M. Clin Ophthalmol 2016;10:1785-90.
26Santodomingo-Rubido J, Wolffsohn JS, Gilmartin B. Comparison between graticule and image capture assessment of lower tear film meniscus height. Cont Lens Anterior Eye 2006;29:169-73.
27Lin PY, Cheng CY, Hsu WM, Tsai SY, Lin MW, Liu JH, et al. Association between symptoms and signs of dry eye among an elderly Chinese population in Taiwan: The shihpai eye study. Invest Ophthalmol Vis Sci 2005;46:1593-8.
28Uchino M, Schaumberg DA, Dogru M, Uchino Y, Fukagawa K, Shimmura S, et al. Prevalence of dry eye disease among Japanese visual display terminal users. Ophthalmology 2008;115:1982-8.
29Kojima T, Ibrahim OM, Wakamatsu T, Tsuyama A, Ogawa J, Matsumoto Y, et al. The impact of contact lens wear and visual display terminal work on ocular surface and tear functions in office workers. Am J Ophthalmol 2011;152:933-4000.
30Nichols JJ, Sinnott LT. Tear film, contact lens, and patient-related factors associated with contact lens-related dry eye. Invest Ophthalmol Vis Sci 2006;47:1319-28.
31Yokoi N, Uchino M, Uchino Y, Dogru M, Kawashima M, Komuro A, et al. Importance of tear film instability in dry eye disease in office workers using visual display terminals: The Osaka study. Am J Ophthalmol 2015;159:748-54.
32Moon JH, Lee MY, Moon NJ. Association between video display terminal use and dry eye disease in school children. J Pediatr Ophthalmol Strabismus 2014;51:87-92.
33Moon JH, Kim KW, Moon NJ. Smartphone use is a risk factor for pediatric dry eye disease according to region and age: A case control study. BMC Ophthalmol 2016;16:188.
34Wagner RS. Smartphones, video display terminals, and dry eye disease in children. J Pediatr Ophthalmol Strabismus 2014;51:76.
35Ilhan N, Ilhan O, Ayhan Tuzcu E, Daglioglu MC, Coskun M, Parlakfikirer N, et al. Is there a relationship between pathologic myopia and dry eye syndrome? Cornea 2014;33:169-71.
36Wang X, Lu X, Yang J, Wei R, Yang L, Zhao S, et al. Evaluation of dry eye and meibomian gland dysfunction in teenagers with myopia through noninvasive keratograph. J Ophthalmol 2016;2016:6761206.
37Jie Y, Xu L, Wu YY, Jonas JB. Prevalence of dry eye among adult Chinese in the Beijing eye study. Eye (Lond) 2009;23:688-93.
38Xu L, Wang YX, Guo Y, You QS, Jonas JB, Beijing Eye Study Group. Prevalence and associations of steep cornea/keratoconus in greater Beijing. The Beijing eye study. PLoS One 2012;7:e39313.
39Chang SW, Tsai IL, Hu FR, Lin LL, Shih YF. The cornea in young myopic adults. Br J Ophthalmol 2001;85:916-20.