The commonly reported ocular infections associated with MH
formation are Ocular Toxoplasmosis (OT) and Cat scratch disease.(130–137) Other rare causes include ocular
Cysticercosis, Lyme disease, acute idiopathic maculopathy (AIM), Toxocariasis,
Syphilis, septic embolism and fungal endophthalmitis.(122,138–144) The existing literature on
infectious causes for atypical MH is described in table 4.

Ocular Toxoplasmosis

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The primary ocular manifestation of
OT is retino choroiditis.(130) The macula is commonly affected in
OT. The tangential and antero-posterior vitreous traction on fovea from
inflammatory contraction of the posterior hyaloid face and PVD acceleration is
the proposed mechanism for MH formation in these eyes.(131–134) In a large scale study of 243 eyes
with ocular toxoplasmosis by Atmaca et al, the prevalence of MH was found to be
0.4%.(130) MH characteristically is large,
associated with vitritis, paramacular lesion and detached posterior hyaloid
face. Often these MH develop during the course of medical management with
either triple therapy or spiramycin therapy.(131,132,134) Surgical closure and visual improvement
even with vitrectomy and ILM peeling is mostly unrewarding.(131,132,134)

Cat Scratch disease

A literature search revealed 3 case reports of MH in Cat
scratch disease.(135–137) The patients had fever, arthralgia
and history of keeping pets (cats). All patients had neuroretinitis with
positive serology for Bartonella. Within few weeks to a month period of starting
the systemic therapy (oral steroid, Azithromycin), a FTMH was documented in all
cases. Pathogenesis of macular hole was ascribed to traction on the macula by
irregular inflammatory contraction of the premacular cortical vitreous. Macular
hole was associated with NSD, stellate exudates and ERM. Surgery was not
attempted in any of these cases.

 

1.           
Miscellaneous

a.           
Tumours

Gold
et al. reported 3 cases of choroidal melanoma with coexisting MH.(145) Two patients had large pigmented choroidal
masses adjacent to MH while one had a recurrent MH with large cilio-choroidal mass
previously treated with iodine-125 plaque brachytherapy. The MH was believed to
arise as a result of combination of tangential retinal traction from enlarging
mass, dehiscence of associated cystic macular changes, and lipid exudation.
Narang et al reported a case of choroidal melanoma with MH formation secondary
to cystoid changes (inflammation-induced increase in capillary permeability).(146)

Gold
et al described a macular hole that developed in a longstanding optic disc
hemangioblastoma that had remained stable for 10 years.(147) The hemangioblastoma may have caused
a pull on the vitreous membrane which resulted in VMT. Pre-operative VA of
20/400 improved to 20/200 at 1 month with successful MH surgery.

b.           
Electric and lightening injuries

Three cases
have been reported involving electrical or lightening injury leading to MH
formation.(148,149) Rao et al. reported a case of
bilateral macular hole following a lightning strike.(148) Rajagopal J et al. reported a case
of unilateral macular hole with coagulated vitreous following an electric shock
injury.(149) The proposed pathogenic mechanisms
for MH formation in such condition include localized elevation of temperature
of the RPE, focal ischemia secondary to the vascular changes that result in
thinning, concussive forces of the electrical shock leading to incomplete
vitreous detachment with residual vitreomacular traction, and  thermal shrinkage of the vitreous body
causing PVD and MH formation.

For FTMH
following electrical injury, surgical intervention is not always recommended.
Lee et al have reported spontaneous closure in such cases.(150) However, prognosis for surgery is usually
poor as ischemic and coagulative retinal necrosis occurs.(148,150)

c.           
Valsalva related

Xie et al. reported a case of Valsalva retinopathy
followed by macular hole formation in a 34 year male.(151) The initial pre-macular haemorrhage
resolved after 3 months with OCT revealing a thickened and hyper-reflective ILM
with intraretinal cystic changes in the NFL at the fovea. Also noted was the
tangential traction by the elevated ILM and incomplete PVD with a MH. At 9
month visit, the haemorrhage completely resolved and the MH persisted. The
mechanisms proposed for MH formation included breakthrough of bleed from the
neurosensory layers, thickened ILM with tangential traction at fovea, and
massive haemorrhage causing tension on the ILM.

d.           
Connective tissue syndromes

Patients with Alport Syndrome have MH (lamellar/full
thickness) as a rare ocular manifestation.(152–157) Alport syndrome is characterised by
dysfunctional type IV collagen (alpha 5 chain) found in the basement membranes
of both Bruch’s membrane and the internal limiting membrane, along with
abnormally strong vitreo retinal adhesion. Clinically the fundus shows
yellowish white mid-peripheral retinal flecks. There is absence of
vitreomacular traction. There occurs abnormal passage of fluid through
dysfunctional Bruch’s membrane and intraretinal fluid accumulation in the form
of small cystic cavities with subsequent disruption leading to FTMH. Giant MHs
have often been reported due to widespread Bruch’s membrane abnormality.(152,154,156)

Surgical challenges in these eyes include difficult
peeling of the ILM due to tightly adherent hyaloid, larger size of MH, and
earlier age at onset.(155) MH closure with vitrectomy and ILMP
has been reported by Miller et al (155)and Viney et al. (157) with limited visual improvement.

e.           
Drug induced

Topical Pilocarpine administration can be associated
with vitreoretinal traction and retinal tears/detachments.(158) It causes forward displacement of
the lens-iris diaphragm and thus anterior movement of the vitreous which
results in traction in areas with anomalous vitreous adherence. Chronic Pilocarpine
use has been found to be associated with MH formation.(159) Also Benedict et al. reported a case
of impending MH or stage 1A MH which resolved after the discontinuation of Pilocarpine.(160)

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