FP46 : Early Post-Operative IOP Rise Between Phacoemulsification & Phacotrabeculectomy in Poag : A Compariso

Dr. M.Shiraz Ali, A10961, Dr. Rajiv Kumar Gupta

Shiraz Ali*, Rajiv Kumar Gupta**

Abstract

Aim:

To compare early post-operative IOP rise between phaco&phacotrab in POAG patients with moderate ONH damage & visually significant cataract.Methods:Out of 95 patients,41 underwent phaco& 54 underwent phacotrab.IOP was measured 24 hours after surgery.Results:The patients’ age,sex ratio & ratio of right eye to left eye did not differ significantly between two groups.In phaco group,pre-op IOP was 16.32 ± 2.09 mm Hg & 24 hours IOP was 16.41 ± 3.52 mm Hg.Change in IOP was not statistically significant (p=0.863).In phacotrab group,pre-op IOP was 17.39 ± 2.57 mm Hg & 24 hours IOP was 16.07 ± 4.11 mm Hg.Change in IOP was not statistically significant (p=0.053).A total of 6 patients in phaco group & 2 patients in phacotrab group had an IOP rise of ≥+5mm Hg.Change in IOP at 24 hours between 2 groups was not statistically significant (p=0.268).Conclusion:We found no added advantage in doing a phacotrab as against phaco with respect to early post-op IOP spikes.

Key Words

Phacoemulsification, Phacotrabeculectomy, Post – operative IOP Rise 

** Associate Professor, Regional Institute of Ophthalmology, Rajendra Institute of Medical Sciences, Bariatu, Ranchi – 834009, Jharkhand, India.

Correspondence to :Dr. M. Shiraz Ali (AIOS No. : A10961), “Eye n You”, Advanced Centre for Cataract & Glaucoma Management, 3^rd Floor, NILE Complex, Old Hazaribag Road, Kantatoli, Ranchi – 834001, Jharkhand, India, Phone No. : +91-9471307505, Email :shiraz _ali786@rediffmail.com

Introduction

Although the management of cataract in patients with glaucoma has changed over the past two decades, the best approach to combined cataract and glaucoma remains controversial.In most cases, where glaucoma is medically controlled, most surgeons would prefer to do a cataract extraction with intraocular lens implantation alone. Triple procedure (cataract extraction with intraocular lens implantation with trabeculectomy) is the preferred choice of treatment in patients with cataract co – existing with medically uncontrolled glaucoma.

However, these procedures are associated with a significant intraocular pressure (IOP) rise during the early post – operative period. Although the pressure can usually be brought under control within the first few post – operative days, patients with advanced glaucomatous damage before surgery may suffer additional irreversible glaucomatous optic nerve head (ONH) damage and visual field loss during this period of IOP spike.

Krupin T, et al, found that IOP rise of ≥ 10 mm Hg was observed in 69 % of patients who underwent only cataract surgery and in 14 % who underwent combined surgery. They concluded that combined surgery reduced the frequency and magnitude of immediate post – operative IOP spikes but did not totally eliminate it.

A study by Hitoshi Yasutani, et al, showed that the mean IOP in POAG group was significantly higher than in control group, although no significant difference was found pre – operatively. They concluded that IOP shortly after surgery was significantly greater in eyes with POAG than in non – glaucomatous eyes.

Hopkins JJ, et al, found that 4 hours after surgery, 5.5 % of patients undergoing combined surgery had IOP ≥ 30 mm Hg, compared to 22.7 % of phacoemulsification patient and these results suggested that triple surgery protected against early post – operative elevation of IOP.

Paulsen, et al, showed that IOP decreased significantly in both groups (phaco – trabeculectomy and phacoemulsification), but patients with combined procedure had fewer early IOP elevations and significantly less medications.

The purpose of this study was to compare the IOP rise in the early post – operative period between phacoemulsification with intraocular lens implantation (Phaco – IOL) and phacoemulsification with intraocular lens implantation with trabeculectomy (Phaco – Trab) in patients with primary open angle glaucoma (POAG).

Materials & Methods

This study was conducted according to the principles of Helsinki Declarationon research involving human subjects. Our Institutional Ethics Committee approved the protocol for the study. Written informed consent was obtained from all subjects who participated in the study. Confidentiality was maintained.This study was prospective, non – randomized and conducted over a period of 2 years.

Inclusion Criteria

Patients with POAG with visually significant cataract and :

• Age > 40 years
• In whom ONH could be clinically visualized with a + 90 dioptre lens
• Moderate ONH damage (Cup : Disc ratio > 0.6 and < 0.8, as ascertained by two glaucoma specialists
• IOP ≤ 21 mm Hg on medications
• IOP > 21 mm Hg, if untreated

Exclusion Criteria

• One – Eyed patients
• Primary angle closure glaucoma
• Secondary glaucomas
• Juvenile glaucoma
• Ocular trauma / Laser / Surgery within past 6 months
• Advanced glaucoma (Cup : Disc ratio ≥ 0.8)
• Intolerance to any medication
• Individuals on > 2 medications for IOP control
• Uncontrolled systemic diseases like diabetes mellitus, systemic hypertension and cardiac disease

95 adult patients were enrolled into the study. Patients with moderate glaucoma, who were on 1 medication and IOP ≤ 21 mm Hg prior to surgery were assigned to Phaco – IOL alone. Patients on > 1 medication and IOP > 21 mm Hg prior to surgery were assigned to Phaco – Trab. 41 patients underwent Phaco – IOL and 54 patients underwent Phaco – Trab.

All eyes were examined thoroughly 7 – 10 days before surgery. At this time, best corrected Snellen visual acuity, Goldmannapplanation IOP, slit – lamp anterior segment examination and dilated fundus evaluation with + 90 dioptre lens were performed.

Patients continued their regular medications until surgery and no sedation was given before surgery. All to – be – operated eyes were started on moxifloxacin 0.5 % eyedrops 6 times on the day before surgery. The eyes were dilated with topical tropicamide 0.8 % and phenylephrine 5 % before surgery.

All surgeries were performed by a single surgeon.

Surgical Technique

Both procedures, Phaco – IOL and Phaco – Trab were done using Alcon Laureate phacoemulsification system.

For both procedures, peribulbar block was given using lignocaine hydrochloride 2 %, bupivacaine 0.5 % and hyaluronidase 1500 IU.

Phaco – IOL

A temporal clear corneal incision was made and anterior chamber was entered with a 2.8 mm disposable angled keratome blade. 2 side – port incisions were made using super blade. After injection of hydroxypropylmethylcellulose2 % viscoelastic material into the anterior chamber, a capsulorrhexis of 4.5 – 5.0 mm diameter was made, followed by hydrodissection and hydrodelineation. A “Stop and Chop” technique was used for phacofragmentation. Residual cortex was removed using bimanual technique. Viscoelastic material was injected to extend the capsular bag. A 6 mm optic, 13 mm haptic, single piece foldable intraocular lens was implanted in the capsular bag using the same main incision. A meticulous viscoelastic material removal was performed using the bimanual technique. Anterior chamber was reformed by hydrating the side – ports. Subconjunctival injection of dexamethasone and gentamycin was given. Eyepad and bandage was applied after instillation of moxifloxacin 0.5 % and povidone iodine 5 % eyedrops.

Phaco – Trab

A 6 mm fornix – based conjunctival flap in superonasal or superotemporal quadrant was raised. Adequate cautery was done to achieve hemostasis. A 4 × 3 mm triangular, partial thickness scleral flap was dissected. Polyvinyl alcohol sponges soaked in MitomycinC  (0.2 mg/ml)  were placed under the conjunctival flap as well as under the scleral flap for 3 minutes. After removal of sponges, the treated area was thoroughly irrigated with 20 ml of balanced salt solution.

After this, the surgeon changed his position to perform phacoemulsification through clear corneal incision temporally. Rest of the steps of cataract surgery were similar to those as of in Phaco – IOL group till viscoelastic material removal.

The surgeon again changed his position to complete trabeculectomysuperonasally or superotemporally. Anterior chamber was entered beneath the scleral flap with a 2.8 mm disposable angled keratome blade. By means of Kelly’s descemets membrane punch, a sclerostomyof 3 × 1 mm was created. A peripheral iridectomy was done with Vannas scissors. Scleral flap was closed with 3 interrupted 10 – 0 nylon sutures; one for the apex of triangular flap and one on each side of the flap. Anterior chamber was reformed by hydrating the side – ports. Conjunctiva was closed with 2 wing 8 – 0 vicryl sutures. Subconjunctival injection of dexamethasone and gentamycin was given. Eye pad and bandage was applied after instillation of moxifloxacin 0.5 % and povidone iodine 5 % eye drops.

Main Outcome Measure

IOP was measured 24 hours post – operatively using a Goldmannapplanation tonometer by a single observer in all patients. Same tonometer was used in all patients. This observer (Observer No. 1) was not masked to the type of surgery. However, to eliminate the bias in IOP measurements, a different observer (Observer No. 2) took the IOP readings after the knob of the tonometer had been adjusted (when there was proper overlap of fluorescent semicircles) by the Observer No. 1.

 Statistical Analysis

All the analysis were performed using SPSS (Version 12). Paired t – test (one – side) was used to compare pre – operative and post – operative IOP. Independent t – test, Mann Whitney test (two – side) was used to compare the two operative procedures. For categorical variables, chi square test was used.

Results

The 95 patients who were originally recruited and assigned to each group completed all scheduled examinations without dropouts and all data were collected.

All surgeries were uneventful.

All Patients

The mean age of patients was 62.87 ± 7.90 years. There were 55 (57.89 %) males and 40 (42.11 %) females. Regarding laterality, 49 (51.58 %) were right eyes and 46 (48.42 %) left eyes.

Phaco – IOL and Phaco – Trab Groups

The mean age in the Phaco – IOL group was 62.37 ± 6.84 years and in the Phaco – Trab group, 63.26 ± 8.67 years.

The patients’ age, sex ratio and ratio of right eye to left eye did not differ significantly between the 2 groups. 

Table 1 : Baseline Characteristics

Parameter	Phaco – IOL Group	Phaco – Trab Group	p Value
Mean Age (Years)	62.37 ± 6.84	63.26 ± 8.67	0.588
Sex Ratio (Male : Female)	25 : 16	30 : 24	0.596
Laterality (Right Eye : Left Eye)	22 : 19	29 : 25	0.997

Phaco – IOL Group

The mean pre – operative IOP was 16.32 ± 2.09 mm Hg and IOP at 24 hours was 16.41 ± 3.52 mm Hg. The change in IOP was not statistically significant (p = 0.863). A total of 5 patients at 24 hours had an IOP rise of 5 mm Hg or more but less than 10 mm Hg. Only 1 patient had an IOP rise of 10 mm Hg or more at 24 hours.

Table 2 :Phaco – IOL Group

Time	No. of Eyes (n)	Mean ± SD IOP (mm Hg)	IOP Range (mm Hg)	p value
Pre – Op	41	16.32 ± 2.09	10 – 21	0.863
At 24 Hours	41	16.41 ± 3.52	10 – 28

 Phaco – Trab Group

The mean pre – operative IOP was 17.39 ± 2.57 mm Hg and IOP at 24 hours was 16.07 ± 4.11 mm Hg. The change in IOP was not statistically significant (p = 0.053). None of the patients at 24 hours had an IOP rise of 5 mm Hg or more but less than 10 mm Hg. 2 patients had an IOP rise of 10 mm Hg or more at 24 hours.

Table 3 :Phaco –Trab Group

Time	No. of Eyes (n)	Mean ± SD IOP (mm Hg)	IOP Range (mm Hg)	p value
Pre – Op	54	17.39 ± 2.57	10 – 23	0.053
At 24 Hours	54	16.07 ± 4.11	10 – 29

 Table 4 : Number of Patients with Rise in IOP of ≥ + 5 mm Hg at 24 Hours

Rise in IOP (mm Hg)	Phaco – IOL Group (n)	Phaco – Trab Group (n)
≥ + 5 and < + 10	5	0
≥ + 10	1	2

 However, the change in IOP at 24 hours between the 2 operative groups was not statistically significant (p = 0.268). 

Table 5 : Change in IOP at 24 Hours (Mean Rank)

	Phaco – IOL Group (mm Hg)	Phaco – Trab Group (mm Hg)	z Value	p value
Change in IOP at 24 hours (Mean Rank)	51.35	45.45	– 1.108	0.268

 Discussion

Transient IOP elevation often complicates cataract surgery in otherwise normal individuals.These IOP elevations can occur in eyes with no history of prior glaucoma. Between 15% to 60% of non – glaucomatous eyes have IOP elevations during the first 24 hours after surgery. The maximum mean IOPelevations occurs between 3 and 24 hours after surgery. Whether to perform cataract surgery alone or combine it with trabeculectomy is an important clinical decision when treating patients who have POAG with a visually significant cataract.

In our study, in the  Phaco- IOL group, the mean pre – operative IOP was 16.32 ± 2.09 mm Hg and IOP at 24 hours was 16.41 ± 3.52 mm Hg. The increase in IOP was not statistically significant at 24 hours from the pre – operative IOP (p = 0.863). In the  Phaco – Trab group, the mean pre – operative IOP was  17.39 ± 2.57 mm Hg and IOP at 24 hours was  16.07 ± 4.11 mm Hg. The increase in IOP was not statistically significant at 24 hours from the pre – operative IOP (p = 0.053). However, the change in IOP at 24 hours between the 2 operative groups was not statistically significant (p = 0.268).

The results from our study suggested  thatthere was no statistically significant elevation of IOP in eyes with moderate glaucomatous ONH damage at 24 hours in eyes subjected to phacoemulsification with intraocular lens implantation alone, as compared to eyes that had trabeculectomy with  phacoemulsification with intraocular lens implantation.

It is expected that in eyes with moderate ONH damage, the resistance to aqueous outflow may only be moderate with ability to withstand any factors likely to increase IOP in the early post – operative period, thereby preventing any acute IOP spike in the early post – operative period.

Trabeculectomy combined with phacoemulsification also increases surgical time, cost of surgical procedure and also entail prolonged visual recovery. These patients also require frequent follow up visits for assessment of bleb function and possible suturolysis.

Trabeculectomy in pseudophakic eyes following clear corneal phacoemulsification is likely to have IOP lowering comparable to phakic eyes without prior ocular surgery.Recent reports also suggest that prolonged IOP control is better with clear corneal phacoemulsification and PCIOL implantation followed by trabeculectomy as a two – staged procedure separated by few weeks to months.

Although IOP rise during early post – operative period was not different statistically between eyes subject to phacoemulsification alone as compared to eyes subjected to trabeculectomy with phacoemulsification with intraocular lens  implantation, longer follow – up is required to evaluate if IOP control with or without additional medications or intervention would be comparable between two groups over a prolonged period.

Conclusion

We found no added advantage in doing a triple procedure as against phacoemulsification with posterior chamber intraocular lens implantation only with respect to early post – operative IOP spikes . Hence, phacoemulsification with posterior chamber intraocular lens implantation is a feasible option as is triple procedure in patients with primary open angle glaucoma and with moderate glaucomatous ONH damage and visually significant cataract.

Declaration of Interest

The authors report no conflicts of interest. The authors have no relevant financial interests in any of the products discussed in this article. The authors alone are responsible for the content and writing of the paper.

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