The timely management of acute PAC is important for reducing the risk of irreversible damage to the optic nerve head and preventing recurrent attacks and chronic angle closure glaucoma (CACG) progression . The retinal fiber layer thickness may decrease significantly within 16 weeks after the attack . Delay in presentation and the time needed to terminate the attack have been found to have a detrimental effect on the final outcome . Conventional options involve the use of medical treatment, paracentesis and laser peripheral iridotomy. In hospital clinics a few patients may be refractory to these treatments and the attack may remain unbroken. Operative options should be considered to lower IOP as soon as possible, but the timing of operations in an acute setting is controversial.
Recently, cyclodiode laser has been described as a safe and effective alternative in the management of medically uncontrolled acute PAC, and the authors demonstrate a good result in five patients only . Most ophthalmologists would consider that lensectomy or trabeculectomy is suboptimal in such situation because of greater risk of operative complications due to the small dimensions of the chamber and the tendency for choroidaleffusion. The complications of lensectomy are: corneal edema, posterior capsular rupture, bleeding, fibrinous inflammatory reaction, and posterior capsular opacification . The complications of trabeculectomy are: shallow anterior chamber, transient IOP elevation, hyphaema, and aqueous misdirection . In medically unresponsive cases of acute PAC, higher risk of surgical failure and complications make trabeculectomy not a preferred choice . In recent times, technological advances in phacoemulsification and small-incision trabeculectomy (SIT) make this option much more viable.
In cases of acute PAC or acute angle-closure glaucoma, phacoemulsification alone has been shown to achieve good IOP control [18–20]. But IOP-spikes may appear in the early postoperative period and pose a potential threat . Phacotrabeculectomy plus intraocular lens implantation has been shown superior than trabeculectomy which is also superior than phacoemulsification in decreasing IOP for primary angle closure-glaucoma (PACG) . Phacotrabeculectomy is more effective than phacoemulsification alone in controlling IOP in medically uncontrolled CACG eyes with coexisting cataract . In eyes with synechial angle closure and cataract, the preferred option is to perform phacotrabeculectomy . With the progress of surgical technique, able to skillfully handle intraoperative and postoperative complications, more and more doctors tend to solve the two problems in combination.
The new procedures and devices aim to lower IOP with a higher safety profile than filtering surgery (trabeculectomy/drainage tubes) are collectively termed “minimally invasive glaucoma surgery (MIGS)” . But these technologies are mainly for open angle glaucoma, surgery for “closed angle” is still dominated by trabeculectomy for Asian eyes . The aim of SIT is to pursue least tissue injury, less complications and better filtering effect. SIT has been introduced in the form of small incision with 3 mm fornix-based conjunctival flap, 1–2 mm short scleral tunnel instead of scleral flap, suture or no suture for incision, reducing operation area and tissue injury [27, 28]. The surgical technique is generally efficacious and relatively safe comparing to the standard trabeculectomy. One study including 41 eyes with medically uncontrolled glaucoma adopted the surgical technique. The glaucoma type included chronic simple glaucoma, chronic narrow-angle glaucoma, pseudoexfoliation glaucoma and pigmentary glaucoma. Most of these patients had IOP at or below the target IOP after mean follow-up of 25 months . Another revised procedure of SIT avoids cutting Tenon’s capsule . The use of a small 2.5 mm limbal incision obviates subconjunctival fibrosis, and it is safer with higher success rate than conventional trabeculectomy .
One important difference between the above SIT studies is the glaucoma type, open angle vs. closed angle over 180° in ours. The patients enrolled in our study suffered with both refractory acute PAC and coexisting cataract. We compared small-incision phacotrabeculectomy with phacoemulsification in treating the two problems. Based on the patients’ preoperative status and eye characteristics, we also revised the procedure in order to achieve the best outcome, including the width of the peritomy, flap size, suture method and etc. The BCVA of most patients was improved in phacotrab group (75 %) and phaco group (80 %). The surgical success rate was 83.33 % in phacotrab group and 72 % in phaco group respectively. The difference in mean IOP at 12 months between the two groups appeared marginal. A longer follow-up would be useful to confirm whether small-incision phacotrab is more effective in IOP control.
Merits of small-incision phacotrabeculectomy for refractive acute PAC with cataract include: less postoperative inflammatory reaction as phaco, better IOP control in the long term, less possibility of IOP lowing medication and progression to glaucoma. In addition, combined phacotrabeculectomy may help elderly patients with less psychological and financial burden. Any operative option should base on the specific condition of ocular diseases and the premise of no violation of evidence-based medicine, taking the most advantageous way for patients. In patients with medically uncontrolled glaucoma and cataract, the options are to perform trabeculectomy first then phacoemulsification, phacoemulsification first and then trabeculectomy, or phacotrabeculectomy . The surgical indications of combined phacotrabeculectomy should be reserved for any one of the following conditions: refractory to drug or laser treatment with high IOP, attack history or moderate to severe optic nerve damage, tendency to malignant glaucoma, requirement of vision improvement, no chance to have 2 separate surgeries due to ocular or systemic conditions, and poor adherence or inconvenience of follow-up, etc. Small-incision phacotrabeculectomy may offer clinical and technical advantages over the standard combined operations where conventional treatment fails.
This study may not have sufficient follow-up duration and sample size to look at other parameters, such as additional IOP lowing medication and glaucomatous progression. Multicenter randomized controlled clinical trials are required to confirm these observations.