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 Table of Contents  
ORIGINAL ARTICLE
Year : 2016  |  Volume : 28  |  Issue : 3  |  Page : 189-192

Refractive error as a risk factor in patients with Macular Telangiectasia type 2A: A case-control study


Department of Ophthalmology, Giridhar Eye Institute, Kochi, Kerala, India

Date of Web Publication2-May-2017

Correspondence Address:
Dr. Anna Elias
Giridhar Eye Institute, Ponneth Temple Road, Kadavanthra, Kochi - 682 020, Kerala
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/kjo.kjo_13_17

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  Abstract 

Aim: The purpose of the study was to determine the role of refractive error as a potential risk factor for macular telangiectasia (MacTel) 2A.
Subjects and Methods: The study was designed as a hospital-based retrospective case–control study. One hundred and three age- and sex-matched participants served as controls. The study was conducted over a 3-year period (April 2011–March 2014). The diagnosis of MacTel 2A was based on the classification by Gass JD and Blodi BA with the addition of optical coherence tomography and fundus autofluorescence features. Data from medical records were entered in a standardized pro forma and analyzed. Spherical equivalent (SEq) was calculated using the spherical dioptric power plus half the cylindrical dioptric power. Statistical analysis was performed using SPSS version 20 and statistical package R 1386 3.1.0.
Results: The mean refractive error (SEq) of the cases was +0.90D and +1.08D among the controls. The refractive errors ranged from −4.00D to +6.75D among the cases. Binary logistic regression analysis was performed to determine the role of refractive error as a risk factor for MacTel 2A. Emmetropia was taken as the reference category. Hypermetropia had an odds ratio (OR) of 2.50 (P = 0.002). Myopia had an OR of 1.50 (P = 0.29). It was inferred that patients with hypermetropia had a 2.50 times higher risk of developing MacTel 2A, compared to emmetropes.
Conclusion: Our study of 103 cases and an equal number of age- and sex-matched controls revealed that hypermetropia was a significant risk factor for the development of MacTel 2A.

Keywords: Fundus autofluorescence, MacTel 2A, refractive error, risk factors, SPSS


How to cite this article:
Elias A, Waghule TP, Hussain RN, Gopalakrishnan M, Anantharaman G. Refractive error as a risk factor in patients with Macular Telangiectasia type 2A: A case-control study. Kerala J Ophthalmol 2016;28:189-92

How to cite this URL:
Elias A, Waghule TP, Hussain RN, Gopalakrishnan M, Anantharaman G. Refractive error as a risk factor in patients with Macular Telangiectasia type 2A: A case-control study. Kerala J Ophthalmol [serial online] 2016 [cited 2021 May 6];28:189-92. Available from: http://www.kjophthal.com/text.asp?2016/28/3/189/205419


  Introduction Top


Macular telangiectasia (MacTel) type 2A, an acquired bilateral neurodegenerative macular disorder, occurs in the fourth to sixth decades of life and results in vision loss either in one or both the eyes; it is also known as idiopathic juxtafoveal telangiectasia type 2A.[1],[2] The etiology and pathogenesis of MacTel 2A remains an enigma. It appears to be a primary neuroretinal degeneration associated with a secondary vascular involvement. It has become evident that photoreceptor loss is integral to the disease, and it may be considered a disease of neural origin.[3] Müller cell dysfunction is a major contributor to the pathological features of MacTel 2A. Müller cells are important for the proper functioning of the retinal capillary endothelium and for the health of the surrounding neurons. The retinal neuronal cells and Müller cells interrelate very closely. They exhibit neuroprotective properties by secreting antioxidants and neurotrophic factors.[4] Hence, Müller cell degeneration is associated with loss of neurons.[5] This leads to central macular thinning and cavities in the retina.[6],[7] Loss of macular pigment in MacTel 2A could be triggered by the impairment of Müller cells.[8]

Aim

The purpose of the study was to determine the role of refractive error as a potential risk factor for MacTel 2A.


  Subjects and Methods Top


The study was designed as a hospital-based case–control study. We reviewed the case records of all the patients in our hospital, diagnosed as MacTel 2A over a 3-year period, April 2011–March 2014. Age- and sex-matched patients taken from the same outpatient population served as controls. The diagnosis of MacTel 2A was made by a senior retinal consultant, based on typical features on biomicroscopic examination, fluorescein angiographic features, spectral-domain optical coherence tomography (SDOCT), and fundus autofluorescence (FAF). The patients with features of concomitant retinal disease such as diabetic maculopathy, branch retinal vein occlusion, or radiation retinopathy, which could confound the diagnosis of MacTel 2A, were excluded from the study. The patients with lens or media opacities significant enough to confound clinical, angiographic, or optical coherence tomography (OCT) imaging were excluded from the study. Every patient underwent a comprehensive, standardized evaluation, which was documented in the medical record of the patient. Data from medical records were entered in a standardized pro forma and analyzed. The following data were included: age, sex, associated systemic diseases, refractive error, best-corrected visual acuity (BCVA), stage of the disease at presentation, detailed slit lamp examination of the anterior segment, intraocular pressure using the Goldmann applanation tonometer, dilated fundus examination using the binocular indirect ophthalmoscope and 20D lens, and stereoscopic examination of the disc and macula using the 78D lens. Axial length was measured in some patients. Color fundus photography, SDOCT, and FAF using Spectralis–HRA OCT (Heidelberg Engineering, GmBH, Heidelberg, Germany) were performed in all the patients. Spherical equivalent (SEq) was calculated using the spherical dioptric power plus half the cylindrical dioptric power. Emmetropia was defined as SEq of 0D. Myopia was defined as SEq more than −0.1D and hyperopia as SEq >+0.1D. The study was performed with the approval of the Institutional Review Board and in accordance with the tenets of the Helsinki declaration.

Statistical analysis

Demographic characteristics of participants were summarized using descriptive statistics, which was expressed in terms of means and standard deviation (SD). Risk factor analysis was carried out using the binary logistic regression model. Categorical data were analyzed using Chi-square test, and continuous variables were analyzed using t-tests. Statistical analysis was performed using SPSS software, version 20.0 (IBM), and statistical package R 1386, version 3.1.0. P< 0.05 was considered as statistically significant.


  Results Top


One hundred and three patients (206 eyes) were enrolled in the study. An equal number of age- and sex-matched participants served as controls which were taken from the outpatient population. Majority of the patients among cases and controls were females, i.e., 76 (73.8%) and the remaining 27 (26.2%) were male.

The mean age of patients with MacTel 2A was 58.63 years (range, 38–76 years; SD, 8.18 years). The mean age of controls was closely matched to that of cases, 58.74 years (range, 38–77 years; SD, 8.13 years).

The BCVA was measured in terms of logMAR. In patients with MacTel 2A, the mean BCVA was logMAR 0.38 (Snellen VA 6/12) (range, 0–1.80 logMAR; SD, 0.35 logMAR). Among controls, the mean BCVA was 0.06 logMAR (Snellen VA 6/6) (range, 0–1.8 logMAR; SD, 0.23 logMAR).

Refractive error was expressed in terms of SEq. Considering patients with MacTel 2A, the mean SEq was +0.90D (range, −1.50–+6.75D; SD, 1.37D). The mean SEq among controls was +1.08D (range, −8.70–+4.75D; SD, 1.64D).

To explore the role of refractive error as a risk factor for MacTel 2A, binary logistic regression was performed with emmetropia taken as the reference category [Table 1] and [Graph 1]. Hypermetropia had an odds ratio (OR) of 2.64 (P = 0.001). Myopia had an OR of 1.91 (P = 0.09). It was inferred that compared to emmetropic patients, hypermetropic patients had a 2.64 times greater risk of developing MacTel 2A which was statistically significant. Myopic patients showed a 1.91 times higher risk of developing MacTel 2A, compared to emmetropic patients. However, it did not attain statistical significance. OR was calculated to determine which of the refractive errors carried the highest risk of developing MacTel 2A [Table 2]. Hypermetropia was determined to have the highest risk of developing MacTel 2A (OR 1.96, P = 0.002), compared to myopia (OR 0.85, P = 0.59) and emmetropia (OR 0.39, P = 0.001).
Table 1: Binary logistic regression, refractive error, and macular telangiectasia 2A

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Table 2: Refractive error as a risk factor for macular telangiectasia 2A

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  Discussion Top


The association between refractive error and MacTel 2A was statistically significant. Binary logistic regression revealed hypermetropic patients to have 2.6 times higher risk of developing MacTel 2A compared to emmetropic patients, which was statistically significant. The patients with myopia had a 1.90 times greater risk of developing MacTel 2A compared to emmetropes. Among the refractive errors, the patients with hypermetropia were found to have the highest risk of developing MacTel 2A. To the best of our knowledge, there has not been any study evaluating the role of refractive error on MacTel 2A. Hence, we compared this study with similar studies related to age-related macular degeneration (ARMD). The Beijing Eye Study and the Central India Eye and Medical Study identified hypermetropia as the single most important risk factor for ARMD in adult Chinese and adult Indians, respectively.[9],[10] Similarly, The Singapore Malay Eye Study, The Rotterdam Study, and the Age-related Eye Disease Study Report Number 3 reported hypermetropia to be a risk factor for ARMD.[11],[12],[13] The Blue Mountains Eye Study indicated that moderate-to-high hypermetropia was significantly associated increased early ARM risk (OR 2.0. confidence interval 1.2–3.4).[14] Sandberg et al. observed in their study that patients with hypermetropia of +0.75D or greater were 24 times at a higher risk of having neovascular ARMD than patients with other refractive errors.[15] A systematic review and meta-analysis on refractive errors and ARMD by Pan et al. concluded after analysis of six cross-sectional studies that hypermetropia was associated with a 1.16 odds of prevalent ARMD.[16] Tao and Jonas in their studies on risk factors for ARMD also revealed hypermetropia to be statistically significantly associated with ARMD.[17],[18],[19] Contrary to the above findings, Ulvik et al. found no statistically significant relationship between refractive error and ARMD.[20] This study concurred with majority of the studies on macular degeneration which revealed hypermetropia to be one of the significant risk factors. The causative factors of MacTel 2A remain elusive. Knowledge of potential risk factors contributes to a deeper understanding of the disease.


  Conclusion Top


This study revealed a significant association between refractive error and MacTel 2A which has not been researched earlier.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Gass JD, Blodi BA. Idiopathic juxtafoveolar retinal telangiectasis. Update of classification and follow-up study. Ophthalmology 1993;100:1536-46.  Back to cited text no. 1
    
2.
Wu L, Evans T, Arevalo JF. Idiopathic macular telangiectasia type 2 (idiopathic juxtafoveolar retinal telangiectasis type 2A, Mac Tel 2). Surv Ophthalmol 2013;58:536-59.  Back to cited text no. 2
    
3.
Cherepanoff S, Killingsworth MC, Zhu M, Nolan T, Hunyor AP, Young SH, et al. Ultrastructural and clinical evidence of subretinal debris accumulation in type 2 macular telangiectasia. Br J Ophthalmol 2012;96:1404-9.  Back to cited text no. 3
    
4.
Bringmann A, Iandiev I, Pannicke T, Wurm A, Hollborn M, Wiedemann P, et al. Cellular signaling and factors involved in Müller cell gliosis: Neuroprotective and detrimental effects. Prog Retin Eye Res 2009;28:423-51.  Back to cited text no. 4
    
5.
Gaudric A, Ducos de Lahitte G, Cohen SY, Massin P, Haouchine B. Optical coherence tomography in group 2A idiopathic juxtafoveolar retinal telangiectasis. Arch Ophthalmol 2006;124:1410-9.  Back to cited text no. 5
    
6.
Charbel Issa P, Helb HM, Holz FG, Scholl HP; MacTel Study Group. Correlation of macular function with retinal thickness in nonproliferative type 2 idiopathic macular telangiectasia. Am J Ophthalmol 2008;145:169-75.  Back to cited text no. 6
    
7.
Paunescu LA, Ko TH, Duker JS, Chan A, Drexler W, Schuman JS, et al. Idiopathic juxtafoveal retinal telangiectasis: New findings by ultrahigh-resolution optical coherence tomography. Ophthalmology 2006;113:48-57.  Back to cited text no. 7
    
8.
Balaskas K, Leung I, Sallo FB, Clemons TE, Bird AC, Peto T. Associations between autofluorescence abnormalities and visual acuity in idiopathic macular telangiectasia type 2: MacTel project report number 5. Retina 2014;34:1630-6.  Back to cited text no. 8
    
9.
Xu L, Li Y, Zheng Y, Jonas JB. Associated factors for age related maculopathy in the adult population in China: The Beijing eye study. Br J Ophthalmol 2006;90:1087-90.  Back to cited text no. 9
    
10.
Jonas JB, Nangia V, Kulkarni M, Gupta R, Khare A. Associations of early age-related macular degeneration with ocular and general parameters. The Central India Eyes and Medical Study. Acta Ophthalmol 2012;90:e185-91.  Back to cited text no. 10
    
11.
Lavanya R, Kawasaki R, Tay WT, Cheung GC, Mitchell P, Saw SM, et al. Hyperopic refractive error and shorter axial length are associated with age-related macular degeneration: The Singapore Malay Eye Study. Invest Ophthalmol Vis Sci 2010;51:6247-52.  Back to cited text no. 11
    
12.
Ikram MK, van Leeuwen R, Vingerling JR, Hofman A, de Jong PT. Relationship between refraction and prevalent as well as incident age-related maculopathy: The Rotterdam Study. Invest Ophthalmol Vis Sci 2003;44:3778-82.  Back to cited text no. 12
    
13.
Age-Related Eye Disease Study Research Group. Risk factors associated with age-related macular degeneration. A case-control study in the age-related eye disease study: Age-Related Eye Disease Study Report Number 3. Ophthalmology 2000;107:2224-32.  Back to cited text no. 13
    
14.
Wang JJ, Mitchell P, Smith W. Refractive error and age-related maculopathy: The Blue Mountains Eye Study. Invest Ophthalmol Vis Sci 1998;39:2167-71.  Back to cited text no. 14
    
15.
Sandberg MA, Tolentino MJ, Miller S, Berson EL, Gaudio AR. Hyperopia and neovascularization in age-related macular degeneration. Ophthalmology 1993;100:1009-13.  Back to cited text no. 15
    
16.
Pan CW, Ikram MK, Cheung CY, Choi HW, Cheung CM, Jonas JB, et al. Refractive errors and age-related macular degeneration: A systematic review and meta-analysis. Ophthalmology 2013;120:2058-65.  Back to cited text no. 16
    
17.
Tao Y, Jonas JB. Refractive error and smoking habits in exudative age-related macular degeneration in a hospital-based setting. Eye (Lond) 2010;24:648-52.  Back to cited text no. 17
    
18.
Chaine G, Hullo A, Sahel J, Soubrane G, Espinasse-Berrod MA, Schutz D, et al. Case-control study of the risk factors for age related macular degeneration. France-DMLA Study Group. Br J Ophthalmol 1998;82:996-1002.  Back to cited text no. 18
    
19.
Maltzman BA, Mulvihill MN, Greenbaum A. Senile macular degeneration and risk factors: A case-control study. Ann Ophthalmol 1979;11:1197-201.  Back to cited text no. 19
    
20.
Ulvik SO, Seland JH, Wentzel-Larsen T. Refraction, axial length and age-related maculopathy. Acta Ophthalmol Scand 2005;83:419-23.  Back to cited text no. 20
    



 
 
    Tables

  [Table 1], [Table 2]



 

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