Re: Unsal et al. Preoperative prognostic factors for macular hole surgery: which is better? Oman J Ophthalmol 2019;12:20-4. [doi: 10.4103/ojo.OJO_247_2017].

To the Editor,

I read with great interest the recent retrospective comparative study by Unsal et al., evaluating the prognostic effects of different optical coherence tomographic (OCT) parameters on the postoperative anatomical and functional success for patients treated for macular hole (MH).[1] While the findings suggest that apical diameter (AD), base diameter (BD), MH volume, and MH index are statistically significantly correlated with postoperative best-corrected visual acuity and may be strong OCT preoperative predictive parameters for postoperative functional success, I noticed some critical points in the paper that I would like the authors to clarify.

The authors reported that eyes diagnosed with idiopathic stage 2–4 MH with at least 6 months postoperative follow-up were included in the study and that, during surgery after applying core vitrectomy through triamcinolone acetonide (10 mg/ml), the posterior vitreous detachment (PVD) was induced with a vitrectomy probe around the optic disc. However, stage 4 MHs have already a preexisting PVD by definition;[2] therefore, I wonder whether the inclusion only of MHs without PVD to the present study may limit the validity of the authors' observations to a more narrow group of MHs. It would be preferable to edit the relevant paragraph in the Method Section of the manuscript as follows: “In eyes without PVD, we applied core vitrectomy with triamcinolone acetonide (10 mg/ml) and we detached the posterior vitreous with a vitrectomy probe around the optic disc.”

The authors also stated that AD, BD, and height (H) of the MHs were manually measured on the OCT image by the same retina specialist using the software on OCT machine and that AD was measured at the minimal extent of the MH, BD was measured at the level of the retinal pigment epithelium (RPE), and H was measured at the greatest height of the MH from the RPE to the vitreoretinal interface. However, it is unclear whether AD, BD, and H were manually measured using the same OCT scan or using different OCT scans, and I wonder whether fact that the author did not use a computerized automated algorithm for the geometrical segmented analysis of MHs to measure these key OCT predictive parameters preoperatively could alter and possibly bias the final results observed, complicating their comparison with previous cited studies.[34] It will be preferable to add to the manuscript the following paragraph as a limiting factor, “In this study, we used the same OCT device for all patients, which did not have a computerized automated measurement software; therefore, AD, BD, and H were manually measured. Performing measurements manually was a limiting factor. In addition, measurements were performed by the same retina specialist and we did not design a double-blind measurement procedure, which is also a limiting factor of the study.

I commend the author's frank acknowledgment in the discussion of the limitations of the present study but seek clarification of the points I have raised.

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Nil.

Conflicts of interest

There are no conflicts of interest.