|Year : 2021 | Volume
| Issue : 1 | Page : 108-110
Pigmentary glaucoma associated with anterior megalophthalmos
Magdalena Popiela, Divya Mathews
Stanley Eye Unit, Abergele Hospital, Llanfair Road, Abergele, Conwy LL22 8DP, United_Kingdom
|Date of Submission||19-Jun-2020|
|Date of Acceptance||10-Aug-2020|
|Date of Web Publication||31-Dec-2020|
Dr. Divya Mathews
Stanley Eye Unit, Abergele Hospital, Llanfair Road, Abergele, Conwy LL22 8DP
Source of Support: None, Conflict of Interest: None
We present a case of anterior megalophthalmos associated with secondary pigmentary glaucoma in the right eye, with other factors contributing to his raised intraocular pressure (IOP). The mechanism of glaucoma was multifactorial – pigment dispersion syndrome, abnormal angle architecture, IOP rises post pars plana vitrectomy with gas, postcataract extraction, element of steroid response. He underwent successful viscocanalostomy to control his IOP. To the best of our knowledge, there is no previous literature publication on viscocanalostomy as a surgical management of glaucoma in an eye with anterior megalophthalmos.
Keywords: Anterior megalophthalmos, megalocornea, pigment dispersion syndrome, secondary glaucoma, viscocanalostomy
|How to cite this article:|
Popiela M, Mathews D. Pigmentary glaucoma associated with anterior megalophthalmos. Indian J Ophthalmol Case Rep 2021;1:108-10
Megalocornea is a bilateral, nonprogressive, congenital condition in which horizontal corneal diameter is larger than 12 mm without associated elevation of intraocular pressure (IOP). It presents in three patterns: simple megalocornea, anterior megalophthalmos compromising of megalocornea, enlargement of iris-lens diaphragm and ciliary ring, and buphthalmos in association with congenital glaucoma., Anterior megalophthalmos is the most common presentation of megalocornea
| Case Report|| |
A 43 year old man presented with right rhegmatogenous retinal detachment. His IOP measured 34 mmHg with 0.5 cup:disc ratio. He was previously followed up in a different ophthalmic department for bilateral megalocornea, high myopia (Right 20/50 snellens equivalent with -8.0 DS/-1.0 DC × 73°, left 20/50 snellens equivalent with -9.0 DS/-2.0 DC × 148°) pigment dispersion syndrome, and open angle with wide ciliary body, features of anterior megalophthalmos. His IOP, disc and visual fields (VF) had been recorded as normal prior to this presentation elsewhere. Visual acuity (VA) at presentation was HM in the RE and 20/50 LE. He was commenced on Guttae (G.) Timolol Maleate 0.5% twice a day to his right eye and underwent right 20G pars plana vitrectomy (PPV) with Hexafluoroethane (EasyGas® C2F6). IOP rose from 20 to 32 mmHg on topical steroids. He required G. Latanoprost (50 μg/mL) with Timolol (5 mg/ml) and G. Dorzolamide 20 mg/mL to control his IOP to 20 mmHg over the next few months. Nine months following his vitrectomy, he underwent uncomplicated right phacoemulsification following which is VA improved to 20/125. One week later, he developed corneal oedema with IOP of 40 mmHg. At this point, he was referred to our glaucoma service. His IOP was unresponsive to medical therapy of G. Latanoprost with Timolol, G. Dorzolamide, G. Brimonidine tartrate 0.2%, and oral Acetazolamide 250 mg four times a day. His vision measured 20/125 Snellen equivalent, due to persistent corneal oedema, with 0.8 Cup:Disc ratio. He underwent uneventful right viscocanalostomy 1 month after his cataract extraction. His IOP was 26 mmHg, and G. Timolol was started in the first postoperative week. At 5 months, right neodymium-doped Yttrium Aluminium Garnet (Nd:YAG) goniopuncture did not improve his IOP, which stayed elevated at 23 mmHg. Due to the side effects of G. Timolol, he was switched onto G. Brinzolamide (10 mg/mL) and subsequently G. Brimonidine added. His corneal oedema resolved, and at the last visit, his IOP was stable at 14 mmHg on this treatment with a vision of 20/80 snellen equivalent. His left VF remained full; however, due to the poor VA VF could not be performed on the right eye.
| Discussion|| |
Anterior megalophthalmos is the most common presentation of megalocornea and is predominantly inherited in X-linked recessive manner. Features of anterior megalophthalmos include large clear cornea of below normal thickness and normal radius, deep anterior chamber with posterior iris insertion, lens subluxation, iridodonesis, anterior iris stromal hypoplasia leading to miotic pupil, pigment dispersion syndrome with iris transillumination defects and Krukenberg spindle on the corneal endothelium, wide angle with broad ciliary body, and short vitreous space. Anterior megalophthalmos leads to early cataract formation and secondary glaucoma due to pigment dispersion and goniodysgenesis.
Our case displays distinctive features of anterior megalophthalmos ([Figure 1]: Bilateral megalocorneas with clear corneas) associated with secondary pigmentary glaucoma in the right eye ([Figure 2]: Iris transilluminations, [Figure 3]: Gonioscopic view of the right eye's trabecular meshwork showing increased pigmentation), with other factors contributing to his raised IOP. All his eye measurements [Table 1] conform to the ones classically found in anterior megalophthalmos. A study by Meire et al. found the axial lengths to be above the normal range in anterior megalophthalmos. Our patient's axial lengths contributed to his myopia, which is a known risk factor for development of both glaucoma and retinal detachment. In addition to this, topical steroid use can increase the IOP. In our case, the mechanisms for the development of glaucoma in the right eye include pigment dispersion and angle dysgenesis, exacerbated by a rise in IOP following vitrectomy with C2F6 and postoperative use of topical steroid. Post cataract IOP rise could have been caused by a pigment surge released into already compromised outflow structures.
|Figure 3: Gonioscopic view of the trabecular meshwork showing increased pigmentationrange|
Click here to view
Our patient underwent viscocanalostomy (VC), which was first introduced by Stegmann. The principle of nonpenetrating glaucoma surgery is to create filtration through naturally occurring channels (trabeculo-descement's membrane as well as dilated Schlemm's canal and its collecting channels) and decrease the outflow resistance. Viscocanalostomy targets the site of pathology in PG, namely the pigment-laden trabeculum, and dilates the SC and its collector channels by injection of high-molecular-weight viscoelastic substance into the cut ends of the canal and underneath the tightly sutured scleral flap, preventing scarring, and aiding in the uveoscleral outflow.
Viscocanalostomy offers bleb-free drainage and a low postoperative complication profile. Shaarawy et al. included few PG patients in their sample, reported complete success in 60% cases and qualified success in 90% at 60 months with reduction in postoperative number of drops. If the aqueous flow though the trabeculo-descement's membrane is insufficient to control IOP a Nd:YAG goniopuncture can be performed, converting a nonpenetrating filtration into a micropenetrating one. This procedure can immediately lower IOP by 39.5%, carrying a success rate of around 80%.
To the best of our knowledge, there has been no previous literature publication on viscocanalostomy as a surgical management of glaucoma in an eye with anterior megalophthalmos. Viscocanalostomy was considered a more suitable surgery for our patient as it has a better safety profile especially in a high myope who underwent previous vitrectomy. This gentleman had already undergone two previous intraocular surgeries compromising the superior conjunctiva, and at the time of VC, his cornea was oedematous compromising the anterior chamber view. Nonpenetrating glaucoma surgeries induce less corneal astigmatism, and there is less corneal endothelial cell loss compared to trabeculectomy. Our patient wished to continue wearing his contact lenses postoperatively and VC without bleb-related complications offered him that option. Viscocanalostomy has a shorter recovery period and is also associated with less postoperative discomfort. Preoperatively, this patient required four antiglaucoma medications, which failed to control his IOP, whereas now he is on two drugs and stabilized.
| Conclusion|| |
Viscocanalostomy with its good outcomes and superior safety profile should be considered as a surgical option in the treatment of this condition.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]