Corneal structure in tilted disc syndrome.

Abuzer Gunduz,Nihat Polat,Ersin Ersan Demirel,Tongabay Cumurcu,Ercan Özsoy

doi:10.5935/0004-2749.20160083

Abstract

To evaluate the central corneal thickness (CCT), corneal volume (CV), and anterior and posterior corneal surfaces using the Scheimpflug imaging system in patients diagnosed with tilted disc syndrome (TDS). The study group (Group 1) and the control group (Group 2) comprised 35 eyes of 35 age-, sex-, and refraction-matched cases. All cases underwent a full ophthalmic examination that included cycloplegic refraction, axial ocular length measurement, and Scheimpflug imaging. The mean age was 34.68 ± 15.48 years in Group 1 and 34.11 ± 12.01 years in Group 2 (p=0.864). The gender distribution was 18 males and 17 females in Group 1 and 16 males and 19 females in Group 2 (p=0.618). All subjects were Caucasian. The spherical equivalent was 3.62 ± 1.75 D in Group 1 and 3.69 ± 1.51 D in Group 2 (p=0.850). There was no significant difference in age, sex, race, or spherical equivalent between groups. There was no significant difference in mean keratometric value and CV3 (the CV in the central 3 mm) between groups (p=0.232 and 0.172, respectively). There were statistically significant differences in CCT, CV5, and CV7 (CV in the central 5 and 7 mm3, respectively) and total CV between groups (p=0.008, 0.003, 0.023, and 0.019, respectively). The values of all parameters were lower in the study group than in the control group. There was also a statistically significant difference in the anterior elevation parameters of the cornea between groups (p<0.05). The mean values of Group 1 were higher than those of Group 2. There were statistically significant differences in the two parameters referring to the posterior elevation of the cornea between the two groups (p<0.05). The results of this study showed that eyes with TDS have thinner CCT, lower CV, and different anterior corneal curvature than normal eyes.

Highlights

Tilted disc syndrome (TDS) is a nonhereditary syndrome characte rized by a congenital optic disc abnormality with an elevation of the superotemporal part and depression of the inferonasal part of the disc, leading to an oblique orientation of its longitudunal axis that affects males and females [1,2]
Another study reported that the orientation of the long axis of the optic disk could indicate the corneal astigmatism axis[6], and Pakravan et al[7] reported an inverse correlation between the optic disk area and central corneal thickness (CCT)
The CCT and mean keratometry (mK) value were obtained directly from the Scheimpflug imaging system and the CV3, CV5, CV7, and total corneal volume (CV) data were compared between the two groups

Summary

Introduction

Tilted disc syndrome (TDS) is a nonhereditary syndrome characte rized by a congenital optic disc abnormality with an elevation of the superotemporal part and depression of the inferonasal part of the disc, leading to an oblique orientation of its longitudunal axis that affects males and females [1,2]. Situs inversus (oblique orientation of retinal vascular structures), myopic astigmatism, peripapillary atrophy, ectasic inferonazal fundus, inferior retinal pigment epithelium, and choroid thinning are frequently present in these cases[1,2]. These findings can be associated with bitemporal hemianopsia, central retinal vein thrombosis, peripapillary subretinal hemorrhage, macular neurosensory retinal detachment, and secondary choroidal neovascularization[3,4]. Myopic astigmatism, which has been reported to be mainly corneal in origin, is the main cause of poor vision in TDS patients[5]. Another study reported that the orientation of the long axis of the optic disk could indicate the corneal astigmatism axis[6], and Pakravan et al[7] reported an inverse correlation between the optic disk area and central corneal thickness (CCT)

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Discussion

Conclusion