Macular hole (MH) is defined as a full thickness disruptionof the neurosensory retina at fovea. In the nineteenth century, interest intothe MH pathophysiology and treatment was limited. Later, Kelly and Wendelperformed the pioneering work on vitrectomy with cortical vitreous detachmentand gas tamponade in MH.(1) This revolutionised the understandingbehind the pathophysiology and management of MH. Primary or idiopathic MH occurs due to abnormalvitreo-foveal traction in the absence of other ocular pathologies. With the continuingadvancements in optical coherence tomography (OCT), the understanding ofidiopathic MH has improved considerably.
Therapeutic strategies such as chromovitrectomy and internal limiting membrane (ILM) peeling are continuously beingoptimised for idiopathic MH. On the other hand, secondary MH arise out ofseveral ocular pathologies. With improvement in imaging technologies, they aremore frequently seen nowadays. The pathogenetic mechanisms, morphology,prognostic factors and surgical outcomes in secondary MH are all equivocal.This article reviews and aims to categorize all reported causes of secondary MHinto meaningful domains which can then help one in determining the prognosisand rationale management approach in individual cases. 1. Typical and atypical macular holesIdiopathic MH develop due to obliqueantero-posterior vitreo-foveal traction (VFT) occurring during the course ofposterior vitreous detachment (PVD).
(2) Old age and female gender areimportant risk factors for idiopathic MH formation.(3) Gass proposed the biomicroscopicdescription and staging of MH from impending to full thickness MH.Trauma and myopia are among the mostcommon causes of secondary MH and their characteristics and management have beenwell documented. Indeed the first MH described by Knapp in 1869 was a traumaticMH.(4) Traumatic MH develops as a consequenceof combination of factors like contusion necrosis, cystoid degeneration, andvitreous traction.(5,6) It is advisable to wait for 6 monthsbefore surgical intervention in such eyes to allow spontaneous hole closure.
(5,6) Myopic eyes develop MH due totangential vitreous traction, rigid ILM and progressive chorioretinal atrophywithin the area of posterior staphyloma.(7,8) Presence of full thickness MH inmyopic retinoschisis is a definitive indication for surgery. However prognosisworsens once MH develop in eyes with foveoschisis.As idiopathic, traumatic and myopic MH are among thecommoner causes of MH and have been discussed in detail in literature, weprefer to use the term ‘typical’ MH for these. The term ‘atypical’ will be usedthroughout the review for rest of the MH. 2. Classification of atypical macularholes The various causes of atypical macular holes arecategorised and mentioned in table 1.
3. Vitreo-retinopathiesRetinitis Pigmentosa (RP), Best dystrophy (BD), andadult onset foveal vitelliform dystrophy (AOFVD) are among the most commonretinal dystrophies associated with secondary MH formation. The characteristicsof MH associated with various vitreo-retinopathies are shown in table 2. Retinitis PigmentosaMacular abnormalities, especiallycystoid macular edema (CME) frequently occur in RP.(9–14) RPE dysfunction and pump failureleads to fluid leakage and CME.
The presence of vitreomacular traction (VMT)may also add to CME formation due to the mechanical pull of cortical vitreouson inner retinal layers. FTMH may form after degeneration of the inner layer ofcysts. Progressive retinal atrophy, epiretinal membrane (ERM) contraction,vascular disturbances, and inflammatory insult are among other presumedmechanism behind MH formation in such eyes.(11,15–17)