Photoreceptor Outer Segment on Internal Limiting Membrane after Macular Hole Surgery: Implications for Pathogenesis

FULL-THICKNESS MACULAR HOLE WITH PERSISTENT BROAD VITREOMACULAR ATTACHMENT: Clinical Characteristics and Surgical Outcomes

PURPOSE

To describe the characteristics and surgical outcomes of full-thickness macular holes (FTMHs) with persistent broad vitreomacular attachment.

METHODS

This was a retrospective, observational case series. Consecutive patients undergoing pars plana vitrectomy for FTMHs with persistent broad vitreomacular attachment (study group) were reviewed. Clinical charts, optical coherence tomography (OCT) features of macular holes, and surgical outcomes were reviewed and compared with those with typical FTMH with focal vitreomacular traction (control group).

RESULTS

A total of 15 eyes of 14 consecutive patients (eight males and six females with a mean age of 60.6 years) were included in the study group. OCT showed a zone of at least 1,500 µm all around the circumference of the fovea where the vitreous was attached. On OCT, epiretinal membrane and epiretinal proliferation were observed in 73% and 87% of cases, respectively. Compared with the control group, the study group was younger (P = 0.027) and had better preoperative visual acuity (P = 0.007). All FTMHs closed after one surgery in both groups, and the postoperative visual acuity of the study group was better than that of the control group (P = 0.002).

CONCLUSION

Full-thickness macular holes may have developed under the condition that the vitreous cortex was broadly attached around the hole. These FTMHs were associated with younger age, better baseline visual acuity, and a higher incidence of epiretinal membranes and epiretinal proliferations compared with macular hole with focal vitreomacular traction. The surgical outcome was favorable, but the pathogenesis of FTMH development remains unclear.

Current management strategies for atypical macular holes

This review evaluates the current surgical management options for refractory and atypical macular holes (MH) and proposes a treatment paradigm for approaching complex cases. A review of literature was performed to deliver a thorough discussion of the epidemiology and pathophysiology of MH as well as the historic evolution of surgical management strategies. With this context established, an update on recent surgical advances for management of large, chronic, and highly myopic MH is provided. New small MH may be adequately treated with pars plana vitrectomy, while those ≥300 μm should undergo internal limiting membrane (ILM) peel. For MH ≥400 μm with risk factors for failure, primary intervention should involve creation of an ILM flap and various methods of flap creation are discussed. For very large MH ≥700 μm or in refractory cases, autologous retinal transplants and other recently proposed procedures should be considered. While typical MHs enjoy high initial surgical success rates, atypical and refractory MH require additional intraoperative and postoperative considerations to maximize surgical success and optimize vision. With many techniques at the surgeon's disposal, patient selection becomes critical to improving outcomes.

SIGNIFICANCE OF PREOPERATIVE EXTERNAL LIMITING MEMBRANE HEIGHT ON VISUAL PROGNOSIS IN PATIENTS UNDERGOING MACULAR HOLE SURGERY

PURPOSE

To investigate the association between the vertical elevation of the external limiting membrane (ELM) and visual outcome in patients undergoing surgery for idiopathic full-thickness macular hole.

METHODS

Retrospective observational study of a consecutive cohort of patients undergoing vitrectomy to treat macular hole. The greatest vertical height of the central ELM above the retinal pigment epithelium (ELM height) was measured on spectral domain optical coherence tomography preoperatively. The relationship of ELM height to other preoperative and postoperative variables, including macular hole width and height, and visual acuity was analyzed.

RESULTS

Data from 91 eyes of 91 patients who had undergone successful hole closure were included. The mean ELM height was 220 μm (range 100-394). There were significant correlations between the ELM height and the diameter of the hole, hole height, and worsening preoperative visual acuity. For holes less than 400 μm in width, better postoperative visual acuity was significantly predicted by a lower ELM height.

CONCLUSION

The ELM height varies widely in idiopathic macular hole. It is higher in eyes where the hole is wider and also when the hole itself is higher. For holes of less than 400 μm in width, a lower ELM height is a strong independent predictor of a good postoperative outcome.

Central mfERG amplitude ratio as a predictor for visual outcome of macular hole surgery

PURPOSE

To investigate whether visual acuity improvement achieved after surgical treatment for macular hole (MH) can be predicted by preoperative multifocal ERG (mfERG) central/peripheral amplitude ratio.

METHODS

Thirty patients with unilateral MH were included. Evaluations with comprehensive ophthalmological examination including best-corrected visual acuity (BCVA) were performed at baseline and 1, 3, 8, 24 and 48 weeks after surgery, while mfERG (Diagnosys LLC; 61 hexagons-30°) and spectral-domain optic coherence tomography (sOCT-Heidelberg Engineering) were performed at baseline and 2 months after surgery. mfERG results are shown by means of the ratio between the amplitudes' average from rings 1 and 2 (central) and rings 4 and 5 (peripheral): the P1 ratio. mfERG data from 20 normally sighted age-matched subjects was used for comparison. A macular hole index (MH index) was defined as the quotient between hole height and base measured on OCT.

RESULTS

Twenty-six patients finished the 48-week follow-up. Mean ± SE (logMAR) preoperative BCVA was 0.93 ± 0.22 and improved in 0.25 ± 0.07 at 48 weeks. mfERG P1 ratio was reduced at baseline and increased significantly after surgery. A significant correlation was observed between preoperative P1 ratio and BCVA gain at week 8 (r = -0.42; P = 0.033). There was no significant correlation between preoperative MH index and postoperative BCVA (P > 0.05).

CONCLUSION

Retinal function assessed using the ratio between central and peripheral mfERG responses might be used as predictor of visual acuity outcome after macular surgery for MH.

Vitreomacular Traction and Outer Retinal Structural Changes

In this case report we aimed to present the outer retinal structural changes secondary to vitreomacular traction (VMT). Outer retinal structural changes occurring secondary to VMT due to incomplete posterior vitreous detachment were described retrospectively with spectral-domain optical coherence tomography in 3 eyes of 3 patients. The patients ranged in age from 58 to 65 years and best corrected visual acuity in the 3 eyes was 4/10, 8/10, and 9/10. All of the patients were symptomatic and exhibited outer retinal microholes at the fovea extending from the retinal pigment epithelium to outer limiting membrane, with an overlying operculum on the detached posterior hyaloid membrane over the macula following spontaneous resolution of VMT. In the mean follow-up period of 32 months, the outer retinal microholes decreased in size but did not completely resolve. As demonstrated in these cases, VMT can cause small outer retinal layer defects without signs of full-thickness macular hole. These lesions can cause symptoms and affect visual function, and may be permanent structural changes.