Frequency of Success after Phaco- Trabeculectomy in Patients with Primary Open & Closed Angle Glaucoma

Introduction: Globally cataract and glaucoma are the top two causes of blindness and in the most cases they occur simultaneously in the same eye. Glaucoma is a progressive optic neuropathy, with characteristic visual field defects, for which a rise intraocular pressure is a key modifying factor. The primary treatment of glaucoma is intraocular lowering medications which are used for both primary open angle (POAG) and primary close angle glaucoma (PCAG). This study can generate positive impact on the quality of life of the patient because through this treatment the patient will only have to undergo one surgery and that will reduce patient’s stress and save time and cost.
Objective: To determine the frequency of success in patients with primary open and close angle glaucoma after phacotrabeculectomy. To compare the frequency of success after phaco-trabeculectomy between primary angle closure glaucoma and primary open angle glaucoma. This descriptive case series was conducted at Helper’s Eye Hospital Quetta, the duration of the study was six months from September 2017 to Feb 2018.
Subject and Methods: There were 363 patients with posterior subcapsular cataract for the Phaco-trabeculectomy were included in this study. Same procedure of Phaco-trabeculectomy was performed and intraocular pressure was assessed after one month. Also data on important effect modifiers is collected and was analyzed in analysis.
Results: The average age of the patients was 52.53±9.20 year. Frequency of success in patients with primary open and close angle glaucoma after phaco-trabeculectomy was 98.9% (259/363). Success rate was high in both group but it was significantly high in primary angle closure glaucoma as compare to primary open angle glaucoma [100% vs. 97.7% p=0.049]. Conclusion: In conclusion, postoperative success rates and IOP levels after phaco-trabeculectomy were found to be very high in primary angle glaucoma patients.
Key Words: Glaucoma, Phaco-trabeculectomy, Close angle glaucoma

INTRODUCTION

Globally cataract and glaucoma are the top two causes of blindness and in the most cases they occur simultaneously in the same eye [1]. World Health Organization, in 2010, reported that 51% the of world blindness is due to cataract, in terms of number this represents 20 million people, while another 4.5 million and 3.9 million people are blind due to open-angle and angle-closure glaucoma respectively [2].

 


1.Assistant Prof, Helper’s Eye Hospital ,Bolan University of Medical and health sciences Quetta.2 .Assistant Prof, Khuzdar Medical College , Khuzdar, Balochistan .3 Shaban Khan , Associate Prof, Helper’s Eye Hospital, Bolan University of Medical and Health sciences Quetta. 5 Chairman Department of Ophthalmology, Bolan University of Medical
and Health Sciences Quetta.


Correspondence: Iftikhar ul Haq Tareen, Assistant Prof, Helper’s Eye
Hospital ,Bolan University of Medical and Health Sciences Quetta.
Mob 03333441186, whatsapp, 03217877701 E.Mail>iftikhartareen@
yahoo.com


Received: June-2019 Accepted: Sep-2019


Postoperative success rates and IOP levels after phaco-trabeculectomy were found to be very high in primary angle glaucoma patients.


Glaucoma is a progressive optic neuropathy, with characteristic visual field defects, for which a rise intraocular pressure is a key modifying factor [3]. The primary treatment of glaucoma is intraocular lowering medications which are used for both primary open angle (POAG) and close angle glaucoma (PCAG). When medical therapy becomes ineffective in controlling intraocular pressure than laser and surgical options are used.  During surgery, by making an artificial outflow pathway to ocular surface, trabeculectomy has become the basic surgical procedure for intraocular reduction in both primary open angle and close angle glaucoma. If cataract coexists with glaucoma  than a combined procedure phacotrabeculectomy is performed [4]. Combined phaco-trabeculectomy has its advantages. First, it reduces risks of additional intra-ocular surgeries, because frequently after trabeculectomy, there is rapid progression of lens opacities into visually significant cataracts that require cataract surgery. Secondly, sequential cataract surgery is associated with increased risk of trabeculectomy failure which may be minimized by combined phaco-trabeculectomy. A study done in Taiwan “Comparison of surgical outcomes after phacotrabeculectomy in primary angle closure glaucoma versus primary open angle glaucoma” in 2014, with 61 patients, shows that the success rate of phaco-trabculectomy was 74% an primary angle closure glaucoma and 62% in primary open angle glaucoma [5]. An other study in Pakistan done by Ch. Javaid Iqbal in Mayo Hospital, Lahore which shows phaco-trabeculectomy is more effective for treating primary angle closure glaucoma patients [6] There are few studies that have documented outcomes, or have done comparison for outcomes amongst patient with Angle-closure glaucoma versus Open-angle glaucoma. Through this study we will generate important evidence of effectiveness of this procedure in Ophthalmological Specialized settings in Pakistan. In addition to contributing academic field the evidence generated from this study will also have a positive impact on the quality of life of the patient because through this treatment the patient will only have to undergo one surgery and that will reduce patient stress and save time and cost.

MATHODOLOGY

The primary objective of this study was to determine the frequency of success in patients with primary open/close angle glaucoma after phaco-trabeculectomy. Secondarily to compare the frequency of success after phacotrabeculectomy between primary angle closure glaucoma and primary open angle glaucoma. Success was labelled as positive if intraocular pressure was less than 21 mmHg on Goldman applanation tonometer attached on slit lamp after one month. Primary angle closure glaucoma: intraocular pressure greater than 21mmHg and grade 2 or <2 of angle on Shaffer Grading on gonioscopy. Primary open angle glaucoma: intra ocular pressure greater than 21 mmHg and grade 3 or >3 of angle on Shaffer Grading on gonioscopy Posterior subcapsular cataract: opacities located in the most posterior cortical layer, directly under the lens capsule on slit lamp examination 

MATERIALS AND METHODS

This descriptive case series was conducted at Helpers Eye Hospital, Quetta (This is a Clinical Ophthalmological specialized care setting). The duration of the study was six months from Sep 2017 to Feb 2018. Sample size was based on WHO sample size calculator (reference no [5]) { P = 62%, d = 5%, n = 363}.Non probability consecutive sampling technique was applied.

Following cases were included in the study.

1. Either gender with age ranging from 40 years to 80 years.
2. Patients of primary open angle glaucoma as per operational definition.
3. Patients of primary angle closure glaucoma as per operational definition.
4. The duration of glaucoma to be considered for the Phaco-trabeculectomy was greater than one year.
5. Patient with posterior sub capsular cataract on slit lamp with duration/maturity of more than one year.

Following cases were excluded from study,

1. Patients with secondary glaucoma (rule out on history and slit lamp examination).
2. Patients with history of diabetes and hypertension
3. Patients with history of previous ocular surgery and history of glaucoma.

After approval from the ethical review committee, patients were enrolled from the OPD who match the inclusion and exclusion criteria. The purpose, procedure, risk and benefits of the study was explained and written informed consent obtained from the patients information on other important socio demographic variables, like age, gender, ethnicity, socio economic status, smoking status will also be calculated. Same procedure of Phaco-trabeculectomy was performed by a single surgeon, intraocular pressure was assessed after one month. The potential biases in the study is limited, as all the patients in the hospital belong to similar socio demographic strata of population. Surgery was done by single surgeon on only for all the patients so the treatment quality was similar for all patients. Also data on important effect modifiers is collected and was analyzed in analysis. Data was analyzed on SPSS 20-0. Mean and SD was calculated for quantitative variables like age duration of cataract, duration of primary angle closure and open angle glaucoma and intraocular pressure. Frequency and percentage was calculated for gender, success (yes or no), ethnicity, socioeconomic status and smoking status. Effect modifiers like age, gender, duration of cataract, duration of primary open and closure angle glaucoma, ethnicity, socioeconomic status, smoking was controlled through stratification post stratification chi square test was apply by keeping p value less than and equal to 0.05 as significant.

RESULTS

There were 363 patients with posterior sub-capsular cataract and glaucoma for the Phaco- trabeculectomy, were included in this study. The average age of the patients was 52.53±9.20 year’s similarly average duration of cataract was 2.37±0.63 months and glaucoma was 2.30±0.60. Male to female ratio was 1:1.4. Regarding ethnicity, most of the patients were Blochi and Pashtun, 92.02% belonged to lower and middle class . Out of 363 patients 19.83% (72/363) were smokers and male. 52.62% cases were diagnosed as primary angle closure glaucoma and 47.38% were primary open angle glaucoma as shown in figure 1.  Pre-operative mean IOP of the patients was 35.87±6.02 (mmHg) and post-operative mean IOP of the patients noted were 13.78±3.01(mmHg) as shown in table 1. Frequency of success in patients with primary angle glaucoma after phaco-trabeculectomy was 98.9% (259/363) as presented in figure 6. Success rate was high in both group but it was significantly high in primary angle closure glaucoma as compare to primary open angle glaucoma [100% vs. 97.7% p=0.049] as shown in table 3. Stratification analysis was performed and observed that rate of success in patients after phaco- trabeculectomy was high in all age groups but there were no significant difference among different age group (p=0.96) while rate of success was significantly high in male as compare to female patients (p=0.037) . Similarly rate of success was also observed with respect to duration of cataract, duration of open and closed angle glaucoma, ethnicity, economic class and smoking status . Comparing the frequency of success after phaco-trabeculectomy between primary angle closure glaucoma and primary open angle glaucoma for age groups, gender, duration of cataract, duration open and closed angle glaucoma, ethnicity, economic class and smoking was also observed but there were no significant finding except female in which success rate was high in both group but it was significantly high in primary angle closure glaucoma as compared to primary open angle  glaucoma (p=0.046).

FIG.1Diagnosis of the patients (n=363)



PACG = Primary angle closure glaucoma
POAG= Primary open angle glaucoma

TABLE 2. Pre and post operative IOP of the study patients


 

 

FIG 6 Frequency of success in patients with primary angle glaucoma after phaco-trabeculectomy n=363


 

TABLE 3 Compare the frequency of success after phaco-trabeculectomy between primary angle closure glaucoma and primary open angle glaucoma



TABLE 4 Frequency of success in patients with primary angle glaucoma after phaco-trabeculectomy with respect to age groups n=363



DISCUSSION:

Trabeculectomy has been the gold standard in controlling IOP in glaucoma patients, irrespective of the angle status or the baseline IOP. Due to the advantage of being able to treat coexisting cataracts and glaucoma in one surgery, phacotrabeculectomy has gained popularity among ophthalmic surgeons over the past decade.[7, 8, 9] One of the major pitfalls of trabeculectomy is the deterioration in visual acuity[10] and the increased incidence of cataract formation after surgery,[11] which can be overcome in combined cataract extraction and glaucoma surgery. Furthermore, despite being a more complex surgery, phacotrabeculectomy has been shown to achieve a favorable visual and refractive outcome that is comparable to phacoemulsification alone.[12,13] With growing aging populations and an increase in cases of glaucoma and glaucoma blindness worldwide, aging populations are particularly at higher risk of glaucoma. It is estimated that glaucoma cases worldwide will increase from 60 million in 2010 to 80 million in 2020. [14] Women bear a larger burden than men because not only do women outlive men, but women also outnumber men and represent 60% of all glaucoma cases combined.[14] As such, awareness of the gender differences might increase attention towards populations at risk. In our study we included 363 patients of either gender with age ranging from 40 years to 80 years. The average age of the patients was 52.53±9.20 years and male to female ratio was found to be 1:1.4 Smoking also has adverse ocular effects. It has been shown to be a risk factor for many common and severe eye diseases, such as Graves’ ophthalmopathy, age related macular degeneration, glaucoma, and cataract. Many of these diseases lead to irreversible blindness. There is also evidence for a dose-response effect of smoking on eye morbidity.[15] In our study out of 363 patients 19.83% (72/363) were smoker all were male. A case-control study has shown that cigarette smokers are more prone to glaucoma than are non-smokers (OR=2.9; 95% CI, 1.3-6.6).[16] On the contrary, another population-based study of 4926 subjects has revealed no difference in the frequency of glaucoma, based on cigarette-smoking status.[ 17] We found frequency of success in patients with primary angle glaucoma after phaco-trabeculectomy was 98.9% (259/363). Success rate was high in both group but it was significantly high in primary angle closure glaucoma as compared to primary open angle glaucoma which is consistent with the previous comparative studies,[8,18] In a study by Lai et al,[8] the PACG group had observed a mean IOP reduction of 12.7 ± 8.3 mmHg, whereas the POAG group showed a mean IOP reduction of 5.0 ± 5.7 mmHg (p < 0.05). Rao et al[18] reported a mean IOP reduction of 8.1 ± 8.4 mmHg in PACG and 5.5 ± 7.3 mmHg in POAG (p ¼ 0.03) after phaco-trabeculectomy. In consistence with the above studies we found the mean IOP reduction was 13.78 mmHg in our study. Salmon reported one of the earliest results of trabeculectomy in primary angle closure glaucoma [19] The IOP was successfully reduced to less than 21 mmHg in 30 eyes (66.7%) without medication, and in 11 eyes (24.4%) with topical glaucoma medication, after a mean follow-up period of 19 months. Sihota et al. also retrospectively evaluated and compared the long-term results of trabeculectomy without anti-metabolite in primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG) in an Asian population with at least 5-year follow up [20]. Among the sixty-four eyes of 64 patients, the qualified and absolute success rates for IOP control showed no significant difference between POAG and PACG eyes.

CONCLUSION:

In conclusion, the results of this study showed that phacotrabeculectomy can reduce IOP in both PACG and POAG patients. Postoperative success rates and IOP levels after phacotrabeculectomy were found to be high in primary angle glaucoma patients and found to be significantly high in Primary angle closure glaucoma than Primary Open angle glaucoma groups.
Conflict of Interest: The authors have no conflict of interest and is not supported or funded by any Drug company or any other source.

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