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Size and vitreomacular attachment of primary full-thickness macular holes
  1. Elise Philippakis,
  2. Franck Amouyal,
  3. Aude Couturier,
  4. Elise Boulanger-Scemama,
  5. Alain Gaudric,
  6. Ramin Tadayoni
  1. Department of Ophthalmology, Hôpital Lariboisière, AP-HP, Université Paris 7-Sorbonne Paris Cité, Paris, France
  1. Correspondence to Dr Elise Philippakis, Department of Ophthalmology, Hôpital Lariboisière, 2 rue Ambroise Paré, Paris 75010, France; elise.philippakis{at}aphp.fr

Abstract

Purpose To study the relationship between the size of primary full-thickness macular hole (MH) and the vitreomacular attachment status.

Design Single-centre retrospective observational case series.

Methods The records of 100 consecutive eyes operated for primary full-thickness MH were retrospectively reviewed. The vitreous status and MH diameter were assessed on the preoperative optical coherence tomography scans. MH were classified depending on the presence or absence of vitreomacular traction (VMT) and their size as small (<250 µm), medium (250–400 µm) and large (>400 µm), as suggested in the International VMT Study Group Classification.

Results 22% of MH had VMT and 13% had both VMT and a diameter <400 µm. The MH diameter was not significantly different depending on the presence or absence of VMT (respectively, 339±134 and 423±191 µm (p=0.094)), with large overlap between groups. Small, medium and large MH were similarly distributed regardless of the presence or absence of VMT (p=0.69).

Conclusions Our series of 100 MH did not reveal any significant relationship between the MH size and the presence or absence of VMT. Only 13% of MH had VMT and a diameter <400 mm, then were eligible for intravitreal ocriplasmin as a possible treatment.

  • Vitreous
  • Retina
  • Imaging
  • Macula

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Introduction

Primary full-thickness macular hole (MH) are defined as an idiopathic disruption of all the retinal layers in the fovea and have been first classified by Johnson and Gass in 1988.1 The advent of optical coherence tomography (OCT), vitreoretinal surgery and histopathological studies have enabled a better understanding of MH pathogenesis and updating MH classification.2 ,3 The most recent classification has been established by the International Vitreomacular Traction Study Group (IVTSG) in 2012 and proposes to classify primary full-thickness MH depending on two dissociated features: their size and the presence of a vitreomacular traction (VMT).4 In fact, the vitreous traction over the fovea at the stage of perifoveal posterior vitreous detachment (PVD) is the most common cause of MH.2 ,5 At this point, the sequence of the PVD is to progress towards macular PVD, partial PVD and then complete PVD.6 Also, it has been reported that MH tend to enlarge over time.7 However, no relationship between the MH size and the PVD stage has been demonstrated so far. The primary aim of this study was thus to analyse the relationship between the size of full-thickness MH and the vitreous status.

Furthermore, the efficacy of pharmacological vitreolysis with ocriplasmin has been shown on the closure of small MH associated with VMT without surgery.8 ,9 Therefore, the secondary aim of this study was to assess the proportion of MH eligible for intravitreal ocriplasmin.

Methods

The records of 100 consecutive patients operated on for full-thickness MH in the Department of Ophthalmology of Lariboisière Hospital, Paris, were retrospectively reviewed (1 January 2012 to 1 March 2013). Eyes presenting with lamellar MH, macular pseudoholes, foveolar pseudocyst, impending MH, traumatic MH, myopic MH, any other retinal disorders or history of vitreous surgery were excluded. Baseline demographics (gender, age), preoperative best-corrected visual acuity (BCVA) and lens status were recorded. Vitreous status was assessed through biomicroscopic fundus examination and OCT scans. A VMT was considered present when a vitreous attachment was observed on the hole edges. When no VMT was found, a partial PVD was defined when the vitreous was still attached to the optic disc and a complete PVD was defined when no vitreous cortex was visible on the OCT scans and a Weiss ring was observed on fundus examination. OCT examinations were conducted using either the Spectralis SD-OCT (Heidelberg Engineering GmbH, Heidelberg, Germany) or the Cirrus SD-OCT 5000 (Carl Zeiss Meditec, Humphrey Division, Dublin, California, USA). On the Spectralis, a high-density B-scan macular volume (5°×20°, 29 lines, 6 mm, spacing 60 µm, ART 5, high resolution, 768×496) was acquired as well as two cross-scans of 30° horizontally and vertically, 9 mm, ART 5, high resolution (1536×496). In a few cases, a 9 mm line passing through the fovea and the optic disc was available. The MH diameter was measured on the horizontal line of the volume that showed the largest diameter, which was considered passing through the foveal centre. The diameter of the MH aperture was the smallest distance between its edges (figure 1). On the Cirrus, images included a macular cube of 128×512 mm (20×20°, 6×6 mm, spacing 47 µm), two high definition 5-line raster (30° width horizontally and vertically, 9 mm, spacing 75 µm). Regarding the measurement of MH size and the vitreous status, both devices were considered equivalent.

Figure 1

Images showing the assessment of macular hole size and vitreous status on optical coherence tomography (OCT) scans. (A and B). The vitreous status assessed on the OCT scans, 9 mm horizontal lines are shown. (A) A macular hole is seen with vitreomacular traction on its edges. (B) The posterior vitreous cortex is still attached to the optic disc and an operculum is visible in front of a macular hole (arrow). (C and D) Images showing the size assessment on horizontal OCT scans passing through the foveal centre. The macular hole size is measured with a calliper as the narrowed distance between the edges. (C) A macular hole is seen with complete posterior vitreous detachment, with diameter of 227 µm. (D) A macular hole is seen with partial posterior vitreous detachment, with diameter of 246 µm.

Patients were then classified based on the double entry of the IVTSG classification as MH with or without VMT and based on the MH size as small (<250 µm), medium (250–400 µm) and large (>400 µm).4

Statistical analyses were performed using Statview software (Abacus, Abacus Concepts, Berkeley, California, USA). Decimal visual acuities were converted into logarithm of the minimum angle of resolution. Data were analysed with descriptive statistics, χ2 tests, Mann-Whitney and Kruskal-Wallis tests, when appropriate. Results were considered significant if the p value was <0.05. This retrospective study adhered to the tenets of the Declaration of Helsinki for research involving human subjects and was approved by the ethics committee of the French Society of Ophthalmology (IRB 00008855 Société Française d'Ophtalmologie IRB#1). Informed consent was obtained routinely from all examined patients who participated in this research.

Results

A total of 100 patients were included with a mean age of 71.1±7 years (52–89 years) and the female gender was predominant (71/29). Baseline characteristics of the studied population are presented in table 1.

Table 1

Full-thickness MH baseline characteristics

The overall distribution of MH into size groups was as follows: 21 small MH, 32 medium MH and 47 large MH. MH distribution depending on the presence or absence of a VMT was 22 MH (22%) with VMT and 78 MH (78%) without VMT. The distribution of small, medium and large MH depending on the presence or absence of a VMT is presented in table 2 and was not significantly different (χ2, p=0.695).

Table 2

Distribution of the full-thickness MH depending on their size and the presence of a VMT (p=0.695)

MH with VMT and a diameter <250 µm represented 6% of the population. MH with VMT and a diameter <400 µm represented 13% of the population.

The mean MH diameter was 339±134 μm (50–568 μm) for MH with VMT and 423±192 μm (80–828 μm) for MH without VMT but the difference did not reach significance (Mann-Whitney, p=0.094) because of the large overlap between groups. Among MH without VMT, the mean diameter was 392±179 μm (81–700 μm) when the vitreous was still attached to the optic disc (partial PVD) and 451±200 μm (81–828 μm) when the PVD was complete (Mann-Whitney, p=0.22). The mean MH diameter was not significantly different depending on the PVD stages, VMT, partial PVD and complete PVD, as shown in figure 2 (Kruskal-Wallis, p=0.11) with a large overlap between groups.

Figure 2

Graphs showing the full-thickness MH diameters depending on the stage of the PVD. The MH tends to be larger with PVD progression without reaching significance (p=0.11) and with very large overlaps. MH, macular hole; PVD, posterior vitreous detachment; VMT, vitreomacular traction.

Discussion

In our series of primary full-thickness MH, we did not find any significant relationship between the MH size and the presence or absence of VMT. The MH tended to be larger when the vitreous progressed in its detachment stages, without reaching significance despite the population size of 100 eyes. This finding suggests that if such a relationship exists, it is not strong enough, especially with such a large overlap, to be used for decision making in an individual patient.

It is commonly accepted that the vitreous traction exerted over the fovea is the cause of primary full-thickness MH.2 ,3 ,5 ,10 ,11 These tractional forces result in a drawbridge elevation of the inner retina12 and are then transmitted along the oblique parafoveal Müller cells, inducing a centrifugal force on the outer retina.13 ,14 This pathogenic sequence explains well the mechanism of MH opening but does not predict its size.15 In our series, we could not find any significant relationship between the vitreous status and the MH size. Indeed, the MH size may vary depending on other phenomena: the initial defect and the enlargement process. Regarding the initial defect, the release of the vitreous traction is often but not always associated with an operculum.16 When present, these opercula consist of a variable association of vitreous collagen, glial cells, internal limiting membrane (ILM), Müller cells and cones.17 Then, the PVD can be associated with an avulsion of such cellular components and impairs the foveal microstructure differently from one patient to another. However, no correlation between the MH size and the presence of photoreceptors in the operculum has been demonstrated so far nor between the hypothetical loss of photoreceptors and the final gap in the ellipsoid zone.

MH are subjected to a progressive enlargement process with time7 which may be induced by two mechanisms. First, the hydration of the hole edges with cyst formation could be one of the forces triggering the enlargement.12 Second, glial cells may proliferate onto the ILM surface creating a secondary traction, leading to MH enlargement and preventing hole-healing by releasing only the vitreous traction.18 In parallel, the PVD progresses from VMT towards partial PVD and then complete PVD.6 Our results showed that the mean diameter of MH with VMT was numerically smaller than that of MH without VMT and that the mean diameter was increasingly larger with PVD progression. However, none of these differences were significant because of the large overlap between the groups. This large overlap may be due to the fact that the PVD and enlargement processes occur at a different pace which may also differ from one eye to another. Then, the vitreous release may occur either later in the enlargement process or very early after the MH opening. Indeed in our series, a VMT was present in 19% of eyes with large MH, whereas it was absent in 71% of small MH.

Therefore, our results support the fact that in clinical practice, full-thickness MH should be characterised using both their size and the vitreous status distinctly as suggested by the new IVTSG classification.4 This conclusion is also interesting considering the use of intravitreal ocriplasmin as a new therapeutic option in the management of primary full-thickness MH <400 µm with VMT, especially for those with a diameter <250 µm. In this specific subgroup, eyes have usually a better baseline visual acuity than eyes with MH diameter >400 µm, a spontaneous closure rate of about 20% at 6 months8 ,19 and a closure rate after ocriplasmin injection of 58.3%.8 In our study of 100 MH, 13 MH had a diameter <400 µm with VMT and only 6 MH had a diameter of ≤250 µm and these eyes were the best candidates for enzymatic vitreolysis.

Our study has some limitations, including its retrospective design. If MH tend to be smaller when a VMT is present, our series could not reveal significance despite the quite large population of 100 eyes. Analysing a larger MH population may help to reach significance. Nevertheless, given the large overlap between groups, the physician would still have to characterise MH using both their size and the vitreous status in clinical practice.

To summarise, in our series of 100 primary full-thickness MH, no significant relationship was identified between the MH size and the presence of a VMT on its edges. PVD progression and MH enlargement are two different processes in primary full-thickness MH, suggesting that MH should be characterised using both their size and the vitreous status distinctly. Small MH may close with the release of the VMT. However, the proportion of these cases at presentation is low.

References

Footnotes

  • Contributors EP, AC and RT designed the study and operated on patients. EP and FA performed the statistical analysis and wrote the first draft of the manuscript. AC and EB-S collected patient data. RT and AG contributed in the manuscript reviewing process.

  • Competing interests EP: travel expenses (Novartis, Bayer, Allergan). EB-S: travel expenses (Bayer). AG: board membership (Alimera, Allergan, Thrombogenics), lectures (Heidelberg, Zeiss) and educational presentations (Novartis, Alcon). RT: board membership (Alcon, Novartis, Allergan, Bausch & Lomb, Pfizer, Alimera, Bayer, Zeiss, FCI, Genentech, Roche, Thrombogenics) and travel expenses (Novartis, Bayer, Allergan).

  • Ethics approval Ethics Committee of the French Society of Ophthalmology (IRB 00008855 Société Française d'Ophtalmologie IRB#1).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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