C l i n i c a l s c i e n c e foveal contour, a break in the inner fovea, an intraretinal split, and intact foveal photoreceptors. However, it has been suggested previously that MPH and LMH are entirely different entities.14 MPH is said to result from the centripetal contraction of an ERM that subsequently leads to verticalisation of the foveal slopes and a sharply punched out defect,24 whereas LMH has been suggested to result from an aborted process of full- thickness macular hole formation, with the characteristic split between the inner and outer retinal layers rather than a foveolar detachment.11 12 23 25 FP has also been described as another separate entity as a precursor to macular hole or lamellar macular hole formation due to direct vitreomacular traction.11 While we have identified morphological features that are characteristic of each lamellar macular defect subtype, more studies are required to study the pathogenesis involved in the formation of lamellar macular defects. As previously reported, epiretinal membranes are a common feature associated with lamellar holes, and they have been suggested to be involved in traction on the fovea and play a role in the formation lamellar holes. Fifty per cent of eyes with lamellar macular defects in our study had ERM, compared with 62% of 29 eyes in the study by Haouchine et al14 and 89% of 19 eyes in the study by Witkin et al.13 Related to the latter study, the higher proportion of ERM found in eyes with lamellar holes could be attributed to the increased resolution of ultrahigh- resolution OCT used.13 Measurements of perifoveal thickness of MPH and LMH were both outside the normal range of retinal thickness (233–253 mm),20 and it is likely that the presence of thickened ERM and retinal folds had confounded the measure- ments of perifoveal thickness in MPH and LMH. Perifoveal thickness of FP could have been thinner due to release of traction of the posterior hyaloid face. While ERM may have an important role to play in the pathogenesis of lamellar macular holes, it must be emphasised that it is not responsible for the formation of all types of lamellar macular defects discussed in this study. It is likely that while ERM may induce the formation of lamellar macular holes whereby ERM exerts a centripetal force on the fovea resulting in a cleft between the inner and outer retina, another mechanism involving avulsion of the foveal tissue or the roof of a pseudocyst can also lead to the formation of lamellar macular defects.11 14 The natural history and visual prognosis of lamellar macular holes resulting from the two different mechanisms may potentially be different and should be studied in longitudinal studies using OCT. A limitation of this study is that it was a retrospective review. Prospective and longitudinal studies involving a large number of lamellar macular hole cases would be useful to provide important information on the potential ability of OCT parameters to predict the natural history of lamellar macular defects, the likelihood of progression to full-thickness macular holes, as well as anatomical and functional outcome of surgical intervention. In summary, the study presented the clinical spectrum of lamellar macular defects and demonstrated the use of OCT imaging in the classification and characterisation of different profiles of lamellar macular defects. Redefining lamellar macular defects into subgroups of macular pseudoholes, lamellar macular holes and foveal pseudocysts gave insight into their visual prognosis and underlying retinal morphology. Prospective long-term studies are important to broaden the understanding of the pathogenesis of each lamellar macular defect subtype and to evaluate the potential of OCT in predicting the natural history and surgical intervention of lamellar macular defects. Acknowledgements: We would like to acknowledge the input from M McGrath and T Smith to the preliminary research related to the manuscript. Competing interests: None. Ethics approval: Ethics approval was provided by Queensland University of Technology Human Research Ethics Committee. Patient consent: Obtained. REFERENCES 1. Chen JC, Lee LR. Clinical applications and new developments of optical coherence tomography: an evidence-based review. Clin Exp Optom 2007;90:317–35. 2. Massin P, Girach A, Erginay A, et al. Optical coherence tomography: a key to the future management of patients with diabetic macular oedema. Acta Ophthalmol Scand 2006;84:466–74. 3. Panozzo G, Gusson E, Parolini B, et al. Role of OCT in the diagnosis and follow up of diabetic macular edema. Semin Ophthalmol 2003;18:74–81. 4. Costa RA, Skaf M, Melo LAS Jr, et al. Retinal assessment using optical coherence tomography. Prog Retin Eye Res 2006;25:325–53. 5. Thomas D, Duguid G. Optical coherence tomography—a review of the principles and contemporary uses in retinal investigation. Eye 2004;18:561–70. 6. Hee MR, Baumal CR, Puliafito CA, et al. Optical coherence tomography of age- related macular degeneration and choroidal neovascularization. Ophthalmology 1996;103:1260–70. 7. Lalezary M, Medeiros FA, Weinreb RN, et al. Baseline optical coherence tomography predicts the development of glaucomatous change in glaucoma suspects. Am J Ophthalmol 2006;142:576–82. 8. Shields CL, Materin MA, Shields JA. Review of optical coherence tomography for intraocular tumors. Curr Opin Ophthalmol 2005;16:141–54. 9. Hee MR, Puliafito CA, Wong C, et al. Optical coherence tomography of macular holes. Ophthalmology 1995;102:748–56. 10. Altaweel M, Ip M. Macular hole: improved understanding of pathogenesis, staging, and management based on optical coherence tomography. Semin Ophthalmol 2003;18:58–66. 11. Haouchine B, Massin P, Gaudric A. Foveal pseudocyst as the first step in macular hole formation: a prospective study by optical coherence tomography. Ophthalmology 2001;108:15–22. 12. Gaudric A, Haouchine B, Massin P, et al. Macular hole formation: new data provided by optical coherence tomography. Arch Ophthalmol 1999;117:744–51. 13. Witkin AJ, Ko TH, Fujimoto JG, et al. Redefining lamellar holes and the vitreomacular interface: an ultrahigh-resolution optical coherence tomography study. Ophthalmology 2006;113:388–97. 14. Haouchine B, Massin P, Tadayoni R, et al. Diagnosis of macular pseudoholes and lamellar macular holes by optical coherence tomography. Am J Ophthalmol 2004;138:732–9. 15. Mori K, Gehlbach PL, Sano A, et al. Comparison of epiretinal membranes of differing pathogenesis using optical coherence tomography. Retina 2004;24:57–62. 16. Wilkins JR, Puliafito CA, Hee MR, et al. Characterization of epiretinal membranes using optical coherence tomography. Ophthalmology 1996;103:2142–51. 17. Gallemore RP, Jumper JM, McCuen BW 2nd, et al. Diagnosis of vitreoretinal adhesions in macular disease with optical coherence tomography. Retina 2000;20:115–20. 18. Gass JD. Lamellar macular hole: a complication of cystoid macular edema after cataract extraction: a clinicopathologic case report. Trans. Am Opthalmol Soc 1975;73:230–50. 19. Schuman JS, Puliafito CA, Fujimoto JG. Optical coherence tomography of ocular diseases. 2nd edn. Thorofare: Slack, 2004. 20. Massin P, Vicaut E, Haouchine B, et al. Reproducibility of retinal mapping using optical coherence tomography. Arch Ophthalmol 2001;119:1135–42. 21. Frangieh GT, Green WR, Engel HM. A histopathologic study of macular cysts and holes. Retina 1981;1:311–36. 22. Guyer DR, Green WR, de Bustros S, et al. Histopathologic features of idiopathic macular holes and cysts. Ophthalmology 1990;97:1045–51. 23. Tanner V, Chauhan DS, Jackson TL, et al. Optical coherence tomography of the vitreoretinal interface in macular hole formation. Br J Ophthalmol 2001;85:1092–7. 24. Allen AW, Gass JD. Contraction of a perifoveal epiretinal membrane simulating a macular hole. Am J Ophthalmol 1976;82:684–91. 25. Takahashi H, Kishi S. Tomographic features of a lamellar macular hole formation and a lamellar hole that progressed to a full-thickness macular hole. Am J Ophthalmol 2000;130:677–9. 1346 Br J Ophthalmol 2008;92:1342–1346. doi:10.1136/bjo.2007.133041