Malignant glaucoma

ciliary block glaucoma

1. Malignant glaucoma Dr Nikhil R P Junior resident

2. Contents Introduction and definition Mechanism Clinical features Differential diagnosis Management Conclusion

3. Introduction Malignant glaucoma is also known as – Ciliary block glaucoma, Aqueous misdirection syndrome, Ciliovitreolenticular block, Hyaloid block glauoma , Posterior aqueoues entrapment It was first described by Von Graefe in 1869

4. It is characterized by normal or increased IOP associated with axial shallowing of the entire anterior chamber in the presence of a patent peripheral iridotomy Not responding to conventional therapy It is an uncommon but serious condition occuring as a complication of intraocular surgery

5. Prevalence 2% to 4% - h/o of acute or chronic angle-closure glaucoma that have undergone filtration surgery 1.3 % - glaucoma surgery alone or combined with cataracts 2.3%- Penetrating surgery Women are three times more likely than men

6. Risk Factors Prior angle closure glaucoma Filtration surgeries: Trabeculectomy Laser treatment : Peripheral laser iridotomy Trabeculectomy Cyclophotocoagulation Use of miotics Trabeculectomy - bleb needling Infection and inflammation Retinopathy of prematurity Retinal detachment Trauma

7. Mechanism Ciliolenticular block Anterior hyaloid obstruction Slackness of lens zonules Posterior pooling of aqueous

8. Ciliolenticular block The tips of the ciliary processes rotate forward and press the lens equator or against the anterior hyaloid ( aphakic cases) Hence creating an obstruction to the flow of aqueous, which pools in and behind the vitreous with a forward shift of lens- iris diaphragm

9. Most common mechanism involved in malignant glaucoma

10. Anterior hyaloid obstruction Breaks in the hyaloid near the vitreous base, allows the posterior diversion of aqueous Obstruction to the aqueous flow is by the anterior vitreous face, which is compressed forward against the ciliary processes in phakic and aphakic forms Hence anterior hyaloid may contribute to ciliolenticular block

11. Slackness of zonules Abnormal slackness or weakness of zonules of causes forward movement of the lens – iris diaphragm along with the pressure from the vitreous resulting in malignant glaucoma Postulated by Chandler and Grant

12. Posterior pooling of aqueous Shaffer hypothesized that an accumulation of aqueous behind posterior vitreous detachment causes the forward displacement of iris-lens or iris – vitreous diaphragm This can be seen by using ultrasound bscan demonstrating echo free zones in vitreous from which aqueous was aspirated

13. Miotic induced malignant glaucoma Action of miotics may produce malignant glaucoma through contraction of ciliary muscle or associated forward shifting of the lens with shallowing of anterior chamber This mechanism have been described for unoperated eyes recieving miotic therapy and in eye treated with miotics after filtering procedure

14. Inflammation and infection Both inflammation and trauma are precipitating factors of malignant glaucoma Endophthalmitis caused by fungal keratomycosis and Nocardia asteroides is associated with malignant glaucoma

15. Clinical features Duration – it might occur in early post op period, delayed by some days, weeks or months Pain Congestion Watering Diminution of vision

16. Myopic shift - Anterior dislocation of the iris-lens diaphragm with secondary improvement of near vision Anterior chamber is shallow or flat centrally and peripherally even though patent iridectomy is present IOP is raised (40-60mmhg)

17. Examination Medical history Determination of predisposing factors Symptoms Slit lamp examination ACD - axial (central and peripheral) shallowing of the anterior chamber Patency of the iridotomy Seidel test should be performed to exclude filtering bleb leaking after filtration surgery. Posterior segment : Ruling out choroidal detachment or suprachoroidal hemorrhage Tonometry – usually reveals increased IOP

18. Ultrasound biomicroscopy (UBM) The rotation of the ciliary body to the front and shallowing of the anterior chamber Marked displacement of the structures of the anterior segment Peripheral irido -corneal touch Forward shift of the lens may be noted

19. Differential diagnosis Pupillary block glaucoma Choroidal detachment Suprachoroidal hemorrhage

20. Pupillary block glaucoma On slit lamp Pupillary block Malignant glaucoma Anterior chamber depth Moderate central anterior chamber depth with forward bowing of the peripheral iris is seen Marked shallowing or loss of central anteior chamber depth Peripheral iridectomy Absent A patent iridectomy may be present

21. Choroidal detachment Choroidal separation with serous fluid is common after glaucoma filtering procedures Shallow or flat anterior chamber, IOP detected is inaccurate and cannot be relied on for diagnosis Anterior chamber shallowing may be secondary to anterior uveal effusion with forward rotation of the lens or iris diaphragm, producing secondary angle closure glaucoma resembling malignant glaucoma

22. The presence of choroidal fluid found on ultrasonography and ophthalmoscopic examination of posterior segment helps in diagnosing the condition Most of these resolve spontaneously as IOP rises In persistent cases or massive cases, scleral incisions are made in inferior quadrants. Straw coloured fluid from suprachoroidal space confirms detachment. AC is reformed with air or saline or both

23. Suprachoroidal hemorrhage This condition may occur hours or days after ocular surgery IOP is elevated associated with pain Shallow anterior chamber depth The surgical approach is same as that of choroidal detachment with drainage of blood from suprachoroidal space and reformation of anterior chamber

24. Criteria to be taken in diagnosing Flattening or shallow AC – central and peripheral IOP is greater than anticipated pressure post filtration surgery, when malignant glaucoma follows after filtration surgery Absence of pupillary block, confirmed by patent peripheral iridectomy Absence of suprachoroidal effusion or hemorrhage confirmed by B scan

25. Management Medical Laser Surgery Management of the fellow eye

26. Medical management Hyperosmostic agents – 20% mannitol iv reduces the pressure exerted by vitreous or oral glycerol can also be given Mydriatic cycloplegic combination – 1% atropine and 10 % phenylephrine drops- relaxation of ciliary muscle there by tightening the zonules , break the ciliary block and push the lens backwards helping in forming anterior chamber

27. Aqueous suppressants – Beta blocker or alpha 2 agoinst or carbonic anhydrase inhibitors to be used to reduce IOP Maintenance therapy – the patient to be on atropine drops to prevent recurrence MIOTICS – CONTRAINDICATED In case of no response within 5 days, laser or surgery is employed

28. Laser techniques Argon laser photocoagulation of the ciliary processes Trans scleral diode laser cyclophotocoagulation has been reported to relive malignant glaucoma Nd : YAG laser hyaloidotomy can be undertaken in aphakic and pseudophakic eyes

29. surgery When medical or laser therapy fails, surgical intervention is required It involves removal of aqueous pockets from the vitreous and restoration of anterior chamber Posterior sclerotomy and air injection Anterior pars plana vitrectomy Lens extraction

30. Posterior sclerotomy and air injection: Sclerotomy is done 3mm posterior to the limbus to break the anterior hyaloid and aspiration of liquid vitreous with reformation of anterior chamber with an air bubble Post operatively – atropine eye drops is given to prevent recurrence

31. Anterior pars plana vitrectomy Anterior vitreous including anterior hyaloid is removed with vitrectomy instruments But both posterior sclerotomy and anterior vitrectomy have risk of serious complications The type of surgery depends on surgeon’s choice Lens extraction( phakic cases)- This is favoured by some surgeons when all the three above procedure fails

32. Management of the fellow eye The fellow eye is at risk of developing malignant glaucoma if it undergoes surgery Hence prophylactic laser iridotomy is done, if indicated If angle closure glaucoma is present, every effort should be made to break the attack before surgery and if attack cant be broken, mydriatic - cycloplegic therapy to be started vigarously after iridotomy and continued indefinitely

33. Conclusion Malignant glaucoma – Therapeutic challenge Patients with h/o MG in fellow and PACG should be closely followed in after glaucoma filtration surgeries Good prognosis with current treatment modalities

34. Thank you