Triple Procedure for Dense Cataractus Neovascular Glaucoma Patients
Condition: IOP Decreased; Visual Impairment
MeSH terms: Vision Disorders; Vision, Low; Glaucoma; Glaucoma, Neovascular
Study type: Interventional

Summary: 
      Background: One of the most difficult refractory glaucomas in treatment is the neovascular
      type and its association with dense cataract add to this difficulty. This study aimed to
      provide results of triple surgical treatment of such conditions.

      Methods: A total of 12 eyes of 12 patients with dense cataractus NVG patients were included
      in this study. The patients mean age was 57.25 ± 5.9 years. The mean pre-operative
      intraocular pressure (IOP) was 47.25 ± 4.04 mmHg with maximum antiglaucoma therapy. The mean
      best corrected distant visual acuities (BCDVA) in log MAR was 2.13 ± 0.38. All the patients
      received intra-vitreal injection of 1.25 mg (0.05 ml) bevacizumab followed by
      phacoemulsification, pars plana vitrectomy (PPV) including pan-retinal photocoagulation
      (PRP), and assisted trabeculectomy with Mitomycin c (MMC). Mean IOP and BCDVA changes were
      the main outcome results of this study.
    

Detailed description: 
      Introduction Ocular ischemia due to diabetic retinopathy (DR) and central retinal vein
      occlusion (CRVO) are the most common causes that contribute to the development of neovascular
      glaucoma (NVG). Ischemic retina derived factors like vascular endothelial growth factor
      (VEGF) that can affect the anterior segment and initiates neovascularization in the iris
      (NVI), neovascularization in the angle (NVA). Aqueous outflow is obstructed when neovascular
      fibrous tissues block the trabecular meshwork and leads to synechial angle closure, thus NVG
      develops. Intraocular pressure (IOP) rise due to NVG lowers the ocular perfusion leading to
      further retinal ischemia, and this in turn induces more neovascularization. The management of
      NVG is very difficult thus; the conventional treatments such as antiglaucoma drugs,
      trabeculectomy, cyclophotocoagulation and cyclocryotherapy have poor success rates. It is
      very important to reduce the ischemic drive promptly for the treatment of NVG. Pan-retinal
      photocoagulation (PRP) is a mandatory and effective in resolving the ischemic condition and
      decreasing the vasoproliferative factors production.[ This management is particularly
      difficult in eyes with dense cataract. However, it is possible to overcome this difficulty by
      doing phacoemulsification and pars plana vitrectomy (PPV) + PRP. Moreover,
      phacoemulsification combined with PPV enables us to apply PRP from the posterior pole to the
      ora serrata peripherally. It has been known that Mitomycin C (MMC) increase the success rate
      of trabeculectomy in patients with NVG. Therefore, in the current study, we performed
      Intravitreal bevacizumab (IVB) injection, phacoemulsification, PPV + PRP and trabeculectomy
      augmented with subconjunctival injection of MMC.

      The aim of this study is to evaluate safety and efficacy of this combined surgical procedure
      to alleviate retinal ischemia, reduce IOP, and improve visual acuity in dense cataractus NVG
      patients.

      Subjects and Methods

      Twelve eyes of 12 patients with NVG associated with dense cataract enough to obscure fundus
      visualization (7 males, 5 females) were included in the study in the period from July 2016 to
      August 2019 at Ophthalmology Department, Faculty of Medicine, Minia University. The patient's
      age ranged from 47 to 66 years with a mean age of 57.25 ± 5.9 years. The underlying cause for
      NVG was diabetes mellitus (DM) in 8 eyes (75%) and CRVO in 4 eyes (33.33%). Vitreous
      hemorrhage was present in half (50%) of the patients. The study was approved by the Local
      Ethical Review Committee and adhered to the tents of Declaration of Helsinki as well as all
      patients singed a written consent after discussion of the potential benefits and risks of
      this triple surgical procedures.

      Preoperative examinations: Routine ophthalmological examinations were done after history
      taking including, age, sex, laterality, etiology of NVG and number of used anti-glaucoma
      drugs. The ocular examination includes estimation of visual acuity, IOP measurement with
      Goldman applanation tonometer, slit lamp examination of anterior segment, gonioscopy
      examination of angle of anterior chamber, biometry and ultrasonography. The demographic data
      were registered as in (Table 1).

      Surgical procedures . In brief: - All procedures were done under peribulbar anesthesia with
      mild systemic sedation. IVB injection of 1.25 mg (0.05 ml) was given 2-6 days before surgery
      using a 27-gauge needle at the inferotemporal quadrant at 3.5-4.0 mm posterior to the limbus.
      Preoperative IV mannitol was given to all cases to lower IOP before surgery beside the full
      anti-glaucoma drugs including: topical Dorzolamide-Timolol combination, Brimonidine tartrate
      and oral Acetazolamide (250 mg) three times a day. Subconjunctival injection of MMC in a dose
      of 0.04mg/ml was done, and a period of 4 minutes was left before Conjunctival opening.

      Fornix based Conjunctival incision was performed and a rectangular scleral flap of 3x4 mm was
      dissected. Separate temporal clear corneal incision phacoemulsification was done with
      intrabagal one-piece hydrophobic IOL implantation. Then, incision was closed with 10/0 nylon
      suture. This was followed by three ports 25-G PPV including core vitrectomy, injection of
      triamcinolone acetonide, induction of PVD, shaving of vitreous base, and dealing with any
      epiretinal membranes. PRP using diode endo-laser was done up to the far periphery (2000-3000
      shots, duration 200 ms; power 400 mw). Fluid-air exchange was then performed and 20% SF6 was
      injected leaving 10 cc of gas to adjust pressure at the end of surgery. Then, the upper
      sclerotomies were sutured by vicryl 7/0 and the infusion cannula was left in place connected
      to the syringe of 20% SF6. Then, Healon was injected into the anterior chamber to maintain
      depth of anterior chamber and trabeculectomy by Kelly punch and peripheral iridectomy were
      done. Scleral flap was sutured by two 10/0 nylon sutures at the corners followed by
      watertight Conjunctival wound closure. More SF6 was injected to adjust IOP and the infusion
      cannula was removed, and its site was sutured with vicryl 7/0 suture. At the end of surgery,
      fluid was injected into the AC to test for filtration of bleb and to make sure that the
      conjunctiva was closed watertight. At last, triamcinolone acetonide subtenon injection was
      given to all eyes.

      Post-operative management: The patients were prescribed prednisolone 1% (predfort, Alcon Co.)
      eye drops QID and tapered through 8 weeks, cyclopentolate 0.5 % TID, moxifloxacin 0.3 mg
      (Vigamox, Alcon Co.) eye drops QID for 2 weeks and ointment of tobramycin and dexamethasone
      at night for 4 weeks. Scheduled follow up visits were advised next postoperative day, one
      week, two weeks, monthly for three months, and then each three months for 2 years.

      All patients underwent full ophthalmologic examination including BCDVA, IOP, gonioscopy, slit
      lamp examination, and dilated fundus examination. Antiglaucoma medications were prescribed if
      IOP was more than 21 mmHg. Baseline results and that of 1, 3 and 6 months, 1 and 2 years were
      included in the statistical analysis. This study main outcome measures were the mean BCDVA
      (log MAR), the mean IOP and the incidence of complications. Successful surgery was considered
      when the target IOP =21 mmHg was achieved without serious complications such as
      suprachoroidal hemorrhage, choroidal effusion, retinal detachment, endophthalmitis, phthisis
      bulbi, or persistent hypotony (IOP <5 mmHg). Complete success was considered when IOP of 6
      -21 mmHg was achieved without any anti-glaucoma drugs, and qualified success when this target
      IOP was achieved with and without the use of anti-glaucoma drugs. Failure was defined as IOP
      >21 mmHg despite the use of maximum tolerated medications, hypotony, or the need for another
      glaucoma surgery.

      Statistical analysis: Statistical analysis was performed with SPSS 19. Data were expressed as
      mean ± standard deviation (SD). Changes in the mean BCDVA and the mean IOP were compared for
      each follow up visit with baseline using paired t test and graphs construction done by using
      Graph Pad Prism 5 program. P value < 0.05 was considered statistically significant.
    

Intervention name(s): Procedure
Intervention type(s): Procedure
Intervention description(s): Triple procedure
Other intervention name(s): Triple procedure
Intervention model: Single Group Assignment
Intervention model description: Manegment of uncontrolled NVG patients with dense cataract
Masking: None (Open Label)
Primary purpose: Treatment