CLINICAL

  POSTERIOR

GET THE “HOLE” PICTURE

FULL-THICKNESS MACULAR HOLES ARE SERIOUS BUSINESS

A 59-YEAR-OLD hispanic female presented for a second opinion of a recent diagnosis of a full-thickness macular hole (FTMH) OD. She said her eye doctor told her she needed immediate surgery. The patient denied any visual loss and had no other ocular symptoms.

Her ocular history was unremarkable, and she reported taking medication for hypertension.

The patient’s BCVA was 20/15 OD and 20/15 OS. Amsler grid testing was normal. Pupils, confrontation visual field and ocular motilities were unremarkable. Dilated examination revealed an epiretinal membrane (ERM) and a discrete reddish, oval lesion in the center of the macula that was about 200μm in diameter OD and a posterior vitreous detachment (PVD) OU. She had no evidence of additional posterior pole or peripheral retinal pathology OU. Watzke-Allen slit beam testing for FTMH OD was negative as well.

Was this patient diagnosed with a FTMH, lamellar macular hole (LMH) or a macular pseudohole?

Here, I discuss the etiology, symptoms, clinical signs and diagnosis/management of FTMH to help you determine the diagnosis of this patient.

A pseudohole, as its name suggests, can masquerade as full thickness macular hole.

ETIOLOGY

FTMHs are believed to be caused by a disruption or traction of the inner retina and vitreous at the vitreoretinal interface during the process of an incomplete or partial PVD. An incomplete PVD can lead to a cascade of complications, including vitreomacular adhesion (VMA) or vitreoretinal traction (VMT). With the advent of OCT, doctors now know that VMT, a complication of the process of PVD, can lead to the formation of FTMH because of the “traction.”

Secondary causes of FTMHs are blunt trauma, cystoid macular edema, macular schisis, degenerative myopia with a posterior staphyloma, rhegmatogenous retinal detachment, solar retinopathy and surgical trauma.

Further, FTMH can occur concomitantly with diabetic macular edema, hypertensive retinopathy and proliferative diabetic and retinal vascular occlusions.

The formation of FTMHs typically progress through a period of weeks to months. A majority of cases are classified as idiopathic or primary and are unilateral, but can be bilateral in up to 30% of patients, according to the “American Journal of Ophthalmology.”

Finally, those age 55 and older and twice as many women as men in this age group are at risk for FTMHs.

SYMPTOMS

FTMHs can range from being asymptomatic (some patients may not be aware of any changes in vision until they experience vision loss in the other eye) to experiencing severe symptoms, depending on the hole’s size.

• Central metamorphopsia

• Central scotoma (can enlarge as the hole enlarges)

• Blurred central vision, which may impact the patient’s reading and/or driving abilities

• Mild to profound vision loss (20/70 to 20/400 as the hole enlarges)

• Floaters or flashes of light (if PVD is present)

• Permanent severe vision loss when untreated

CLINICAL SIGNS

The clinical signs depend on the stage of the macular hole. The International Vitreomacular Traction Study Group expanded the widely accepted Gass classification to include VMA, VMT and macular hole, as published in “Ophthalmology.”

• Stage 1 (impending macular hole). This is a macular cyst that presents as either a central yellow spot 100μm to 200μm in diameter (1A) or as an occult hole with a yellow ring 200μm to 350μm in diameter (1B) that represents centrifugal displacement of the foveolar retina and xanthophyll pigment. A VMT with a foveal detachment is observed in this stage. Stage 1 is on its way to becoming an FTMH.

• FTMH. The classic feature of an FTMH is a round, reddish defect. This falls under Stage 2, Stage 3 and Stage 4. Stage 2 is an early full-thickness hole <400μm in diameter that causes a vision decrease range of 20/70. It is associated with VMT.

Stage 3 is ≥ 400μm in diameter with a cuff of subretinal fluid, intraretinal edema and cysts, drusen-like deposits, which may represent macrophages at the level of the retina pigment epithelium, a rim of retinal pigment epithelium hyper/hypopigmentation (spacing) and visual acuity that ranges from 20/100 to 20/400. It is also associated with VMT.

Finally, Stage 4 is characterized by Stage 3 clinical signs with a complete PVD, Weiss ring and an ERM. It is not associated with VMT. With chronicity, the underlying retinal pigment epithelium atrophies, revealing a bull’s-eye appearance.

• LMH. This is most commonly used to identify an aborted macular hole. It appears as a round or irregular, well-circumscribed reddish lesion with intact outer layers of the retina, including the photoreceptors. As a result, VA remains relatively good, usually 20/40 or better. The majority of LMH patients have an associated ERM.

• Pseudoholes. These are difficult to distinguish from an FTMH on clinical examination, as they too appear as reddish, oval lesions in the center of the macula with a PVD and an ERM. Unlike FTMH, however, VA in these patients is near normal, and patients are asymptomatic. Also, OCT, which definitively rules out FTMH, reveals intact photoreceptors with no foveal tissue loss.

DIAGNOSIS/MANAGEMENT

A definitive diagnosis of a Stage 1 macular cyst or FTMH can be obtained via the following:

• VA. A decline in visual acuity is a sign of hole progression.

• Amsler grid. Use this to detect metamorphopsia and central scotoma.

• Diagnostic lenses. Use lenses, such as central lenses, that allow for a large field of view and high resolution, to assess for Stage 1.

• Watzke-Allen slit beam. This is useful for diagnosing FTMH. The test is performed at the slit lamp with a fundus lens and by placing a narrow vertical slit beam through the fovea. A positive result is obtained when a central break is noted in the vertical light beam. (Alternatively, the slit beam of light can be presented using a Maddox rod or a direct ophthalmoscope.)

• OCT. This aids in the diagnosis and staging of FTMHs in addition to providing anatomical detail, including the presence of VMA, VMT and ERM formation. Also, it helps in the differentiation of a FTMH from LMH and pseudoholes and aids in patient education and follow-up care.

The American Academy of Ophthalmology Preferred Practice Panel, as published in “Ophthalmology,” includes the following recommendation for management.

For stage 1, patients should be observed with follow-up every two to four months and instructed to use home Amsler grid testing to monitor their vision.

Stage 2 patients should be referred for a vitreoretinal surgery or the non-surgical option of vitreopharmacolysis with ocriplasmin intravitreal injection, 2.5 mg/mL (Jetrea, ThromboGenics). The latter is FDA approved for enzymatic dissection of the vitreous from the retinal surface for VMA/VMT. Patients who undergo vitreopharmacolysis have a 40% chance of macular hole closure, says “The New England Journal of Medicine.” If vitreopharmacolysis does not induce the release of the VMA/VMT with closure of the hole at one-month follow-up, patients may undergo vitreoretinal surgery.

For Stages 3 and 4, refer the patient for vitreoretinal surgery. (The frequency and timing of subsequent visits varies depending on the outcome of surgery and the patient’s clinical course.)

Pars plana vitrectomy with gas bubble exchange with facedown positioning is the surgical treatment for macular holes. Surgical complications include endophthalmitis, retinal breaks/detachments, cataracts, reopening and enlargement of the macular hole and retinal vascular occlusions.

Patients who have chronic macular holes do not appear to benefit from surgery. Therefore, low vision rehabilitation offers potential assistance.

Approximately 50% of Stage 1 macular cysts undergo spontaneous resolution, according to “Ophthalmology.” On the other hand, about as many may progress to FTMH, says the “British Journal of Ophthalmology.” Also, up to 75% of Stage 2 macular holes progress to Stage 3 and Stage 4, according “Archives of Ophthalmology” and, thus, should be treated promptly by a retinal specialist.

Special attention should be paid to the patient’s fellow eye, as 10% to 20% risk developing a FTMH in the fellow eye in five years, especially in the presence of VMT, says “Ophthalmology.” Additional risk factors for developing a macular hole in the fellow eye include macular thinning and retinal pigment epithelial defects. That said, the presence of a PVD in the unaffected eye lowers the risk of hole development in the other eye to almost 0%, according to “Ophthalmology.”

LMH and macular pseudohole are usually monitored every three to six months because of their stability and the patient’s relatively good vision. These patients are also instructed to monitor their vision and use home Amsler grid testing to do so.

THE ANSWER

If you diagnosed this patient with a pseudohole, you are correct! The aforementioned patient demonstrated excellent VA, an ERM on dilated exam, and OCT helped confirm the pseudohole diagnosis. Further, a complete PVD was seen in her fellow eye, reducing the risk of a FTMH developing. She was educated on her condition and reassured that no surgery was necessary. The patient returned for follow-up three months later with no changes in vision or clinical appearance. She was advised to continue her home Amsler grid and has been monitored closely.

Macular holes remain a potential cause of severe vision loss that can impact a patient’s quality of life. As an optometrist, you play a critical role in the early diagnosis and prompt treatment leading to visual recovery. Make sure the diagnosis is the correct one. OM

SHERROL A. REYNOLDS, O.D., F.A.A.O., is an associate professor at the Nova Southeastern University College of Optometry and clinical preceptor/attending in the college’s diabetes and macular clinic. She is a fellow of the Optometric Retina Society and chairperson for the Florida Optometric Association Healthy Eyes Healthy People Committee. Comment at tinyurl.com/OMcomment.