Analysis of clinical profile and outcome in cases of lens-induced glaucoma

INTRODUCTION

Lens-induced glaucoma (LIG) is an ocular condition that is characterized by a sudden increase in intraocular pressure (IOP), leading to secondary glaucoma.^[1] This is mostly associated with a mature or hyper-mature cataract and occasionally with an immature senile cataract.^[1,2] LIG can manifest in more than one form; the first being secondary angle-closure glaucoma (phacomorphic glaucoma and glaucoma induced by lens dislocation) and the second as secondary open-angle glaucoma (including phacolytic glaucoma, lens particle glaucoma, and phacoantigenic glaucoma).^[3] The crystalline lens can contribute to glaucomatous conditions through several mechanisms, which are broadly classified into two main categories.

1. In the first mechanism, the trabecular meshwork gets obstructed by lens proteins/materials or inflammatory cells. The conditions linked to this are phacolytic glaucoma and lens particle glaucoma. In addition, in some rare instances, an inflammatory reaction to lens material, referred to as phacoanaphylaxis, can lead to an increase in IOP.^[4]

2. In the second mechanism, the lens captures the pupillary area, causing obstruction of aqueous flow which is supposed to flow from posterior to anterior chamber, leading to a rapid increase in IOP. The conditions linked to this mechanism are pupillary block glaucoma, ectopia lentis, and phacomorphic glaucoma.^[5]

Patients of LIG present with acute eye pain, redness in the eye, decreased vision, and headache. The primary goal when we are aiming to treat this condition is to control inflammation and decrease IOP. Regardless of the presentation, the primary treatment focus has been the removal of the cataractous lens. Conventionally, LIG was managed by intracapsular cataract extraction. However, in recent years, extracapsular cataract extraction has become the preferred approach. Evidence supports the safety of a planned extracapsular cataract extraction followed by posterior chamber intraocular lens (PCIOL) implantation in cases of phacolytic glaucoma. Time interval between the onset of symptoms and the initiation of therapy largely influences the success of surgery.^[6] Delay in the management of senile cortical cataract can result in LIG, which can cause an elevation in IOP resulting in degeneration of the optic nerve. In India, socioeconomic barriers continue to hinder access to high-quality surgical care. The growing backlog of cataract cases is exacerbated by population growth and increased life expectancy, leading to suboptimal use of available cataract surgical services, particularly among rural communities. Ocular morbidity as a consequence of lens-induced glaucoma remains prevalent. The purpose of the present study is to investigate the epidemiological profile of LIG, its clinical presentation, pre and post-operative visual outcomes, and pre and post-operative IOP.

MATERIALS AND METHODS

This study was a prospective observational analysis conducted on 120 eyes diagnosed with LIG over a 23-month period, from November 2019 to September 2021, at the Regional Institute of Ophthalmology, Institute of Medical Sciences, Banaras Hindu University. The study received approval from the Ethical Committee at the Institute of Medical Sciences, Banaras Hindu University, and was conducted in line with the Declaration of Helsinki. Written and informed consent was taken from all participants before including them in the study.

All patients of LIG who were willing to participate and gave consent were included in the study. Unwilling patients, patients with LIG having significant anterior segment and posterior segment disorder and those not fit for surgery were excluded from the study.

A total of 120 cases of various forms of LIG, who have met the predefined inclusion and exclusion criteria, were enrolled in the study. These patients typically present with symptoms such as eye pain, vision loss, and redness, along with an intumescent, mature, or hyper-mature cataractous lens and elevated IOP in excess of 21 millimeters of mercury (mmHg). Each patient underwent a brief general assessment (including any comorbid conditions) and a comprehensive ocular assessment, including a detailed history and specific information related to the ocular condition. This assessment also covered general demographic details such as the patient’s age, gender, education, occupation, and place of residence. The ocular assessment included visual acuity, best-corrected visual acuity (BCVA), IOP measurement using an applanation tonometer, anterior segment examination by slit lamp biomicroscopy, and posterior segment examination using both direct and indirect ophthalmoscopes. Out of 120 cases, gonioscopy was performed in 113 cases while 7 had hazy cornea. Synechial angle closure with peripheral anterior synechiae (PAS) ≥180° was shown in 19 cases, 21 had open angle in which 19 had phacolytic material and 1 had lens particle at angle and rest of all the cases had either occludable angle or closed angle. Ultrasound B scan was done where the posterior segment was not visualized due to dense cataract. The type of LIG was determined based on clinical diagnosis.

Management of these 120 cases was aimed to preserve visual acuity, alleviate pain, and reduce IOP to near-normal levels. For all cases, cataractous lens extraction with intraocular lens (IOL) implantation was planned with pre-operative intravenous mannitol, despite a guarded visual prognosis. Regardless of the degree of IOP reduction, surgery was performed in all cases. Figure 1 shows pre-operative phacomorphic glaucoma and Figure 2 shows post-operative. The type of surgery (phacoemulsification or small incision cataract surgery [SICS]) was based on surgeon preference. Combined surgery was done where synechial angle closure with PAS ≥180° was formed and IOP was raised despite medical management. Cataract extraction with PCIOL with iridectomy was done to augment the IOP control where the cornea was hazy (gonioscopy not performed) and IOP was raised. Rest of the cases where PAS was not formed or ≤180° underwent cataract extraction with PCIOL. After administering a peribulbar block, sufficient digital pressure was applied to all patients, except in those cases with displaced lens, for approximately 10–15 min to achieve optimal hypotony. Cataractous lens extraction with IOL implantation under mannitol was carried out in most cases. However, in severe instances of anterior lens dislocation with pupillary block glaucoma, IOL implantation was deferred following lens extraction. In the post-operative period, patients were treated with a combination of topical antibiotic and steroid 6 times a day which is tapered over 4–6 weeks, mydriatic-cycloplegic drops twice a day, and lubricants. In cases of severe uveal inflammation, a short course of systemic steroids was administered. If elevated IOP was noted, IOP-lowering agents were advised. Follow-up appointments were scheduled at 1, 2, 4, and 6–12-week intervals. During each follow-up visit, patients underwent assessment of visual acuity, IOP, and anterior and posterior segment evaluation, and any complication observed was also noted. Below Flow chart 1 shows case selection and management.

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Flow chart 1:

Showing case selection methodology and management. IOP: Intra-ocular pressure, LIG: Lens induced glaucoma, PAS: Peripheral anterior synechiae, PCIOL: Posterior chamber intra-ocular lens, SFIOL: Scleral fixated intra-ocular lens, PC: Posterior capsule

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Figure 1:

Pre-operative image of phacomorphic glaucoma.

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Figure 2:

Post-operative image of phacomorphic glaucoma.

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RESULTS

A total of 120 patients diagnosed clinically as LIG were included in this study. Age group distribution is shown in [Figure 3]. The age range was 53–82 years with mean of 66.945.38 years. The most affected age group of patients in our study was 61–70 years, 83 (69.2%). Gender distribution with female preponderance 79 (65.2%) as compared to males 41 (34.2%) is shown in [Figure 4]. The majority of the patients are from rural areas 75 (62.5%) [Figure 5]. Phacomorphic glaucoma was the most common type of LIG with 82 (68.3%) followed by phacolytic 34 (28.3%) [Figure 6]. Most of the patients 85 (70.8%) were presented to hospital at or within 7 days of ocular symptom [Figure 7].

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Figure 3:

Age group distribution.

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Figure 4:

Gender distribution.

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Figure 5:

Residence.

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Figure 6:

Types of lens-induced glaucoma.

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Figure 7:

Duration of symptoms.

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The comparison of pre-operative BCVA, post-operative uncorrected visual acuity (UCVA) at 1 week, and post-operative BCVA at 4–12 weeks is demonstrated in Table 1. Pre-operative BCVA was very poor in all patients with <3/60 in most of the patients. At 1 week post-operatively, patients recovered their visual acuity with UCVA were 6/18–6/60 in 51 (42.50%), while rest of the patients have <6/60 while at 4–12 weeks, more than 50% of patients had BCVA >6/60. Table 2 demonstrates the comparison of pre-operative IOP and post-operative IOP at 1 week at 4–12 weeks. Pre-operative IOP was very high (≥40 mmHg) in most of the patients, while postoperatively, at 1-week IOP in the majority of 60 (50.0%) patients was < 21 mmHg and at 4–12 weeks, this number increases to 85 (70.8%).

The majority of patients underwent cataract surgery which included both SICS and phacoemulsification with PCIOL (both rigid and foldable IOLs) 91 (75.8%), followed by 19 (15.8%) patients had combined surgeries (cataract surgery with trabeculectomy) [Table 3].

Post-operative BCVA (4–12 weeks) was correlated with pre-operative IOP rise. More than 50% of patients presented with IOP <40 mmHg had BCVA ≥ 6/60, while when IOP was more than 40 mmHg, around 50.0% had BCVA <6/60 [Table 4].

The most common symptom was ocular pain 91 (75.8%) followed by defective vision 88 (73.3%). Few patients had poor visual acuity at the last follow-up, with optic atrophy 8 (6.7%) taking the most common cause followed by corneal edema with striate keratitis 4 (3.3%). Post-operative BCVA (4–12 weeks) was correlated with the duration of symptoms. When patients reported to the hospital at or within 7 days, out of 85 majorities, 38 (44.71%) of the patients had final visual acuity between 6/18 and 6/60, followed by 28 (32.94%) between 6/6 and 6/12 and rest 19 (22.35%) had visual acuity <6/60, while those patients who reported after 7 days, 18 (51.43%) had final visual acuity <6/60 and 17 (48.57%) had between 6/18 and 6/60.

DISCUSSION

Since cataracts are the leading cause of blindness in India, LIG is relatively frequent, especially among the older population in rural areas. In our study, we found that all cases were over 50 years of age, with the majority being, falling within the 61–70-year age group. Data collected from Abdolahi et al.,^[7] also reveals LIG to be a disease of increasing age and our study has a mean age of 66.94 years which is similar to the study in Ramakrishanan et al.,^[8] and Sitouli et al.,^[9]

In our study, LIG was more prevalent in females than in males, with a ratio of 1.9:1, a similar result shown in Pradhan et al.,^[10] and Ushalatha et al.^[11] The cause may be lesser attention given to old women due to socioeconomic and cultural factors leading to the late presentation of cataracts. In our study, 70% of cases visited the hospital within 1 week. In comparison, Ushalatha et al.,^[11] reported that 86% of patients sought hospital care within 10 days. Majority of patients 75 (62.5%) in our study belong to rural population. Similar findings were seen in Preethi et al.^[12]

The clinical features presented in the majority of the cases were ocular pain, redness, and diminution of vision. These symptoms are due to significant raised IOP similarities seen in Tyagi et al.^[13] The present study shows that phacomorphic glaucoma (68%) was more common than any other form of LIG, similar to the study of Vudayana et al.^[14] Phacomorphic glaucoma is likely the most common form in India due to the high prevalence of cortical cataracts in the region. Out of 120 cases, combined surgery was performed in 19 (15.8%) cases with longer duration of presentation where synechial angle closure with PAS was formed. Cataract extraction with PCIOL with iridectomy was done in 7 (5.8%) cases where pupillary block was present in longstanding cases of phacomorphic glaucoma where cornea was hazy. Rest of the cases who presented early and PAS was not formed underwent cataract extraction with PCIOL. At presentation and during our follow-up, we selected several parameters for evaluation, including visual acuity, IOP, and fundus examination. At presentation, visual acuity was recorded as hand movement close to face or worse in 111 cases (92.5%). Only 8 (6.67%) cases had visual acuity between 3/60 and finger count close to face, with no patients presenting with visual acuity better than 6/60. Our findings are consistent with those reported by Kothari et al.^[15] In this study, 2 cases did not show any post-operative visual improvement. BCVA up to 6/60 was achieved in 83 (69%) cases. The poor visual acuity observed was primarily due to optic atrophy, followed by persistent uveitis and corneal decompensation. Rijal and Karki,^[16] also identified optic atrophy as the most common cause of reduced visual acuity. These cases typically had a long duration between the onset of symptoms and initiation of treatment, highlighting that earlier surgical intervention generally leads to better visual outcomes.

The mean IOP in our study was 42.85 mmHg, with a range of 26–60 mmHg. This finding is consistent with the mean IOP of 44 mmHg (range of 24–68 mmHg) reported by Kothari et al.^[15] and 42.5 mmHg (range of 33–59 mmHg) reported by Sharanabasamma and Vaibhav.^[17] Thus, the mean IOP in the majority of cases in our study, as well as in other studies, was around 40 mmHg. In our study, post-operative IOP was <20 mmHg in 85 (70.8%) and >30 mmHg in 4 (3.3%) cases. Similar findings were seen in other studies of 21 mmHg or less in 87% of cases. Pradhan et al.,^[10] ranged from 14 to 22 mmHg in Rijal and Karki.^[16] In our study, the impact of pre-operative IOP on final visual outcome we found that out of 52 patients who had IOP 40 mmHg or less at presentation, 24 (46.2%) have BCVA between 6/8 and 6/12, 25 (48.10%) in between 6/18 and 6/60, and only 3 (5.8%) is <6/60 while rest 68 whose IOP was >40 mmHg; at presentation, out of that only 4 (5.9%) have BCVA between 6/6 and 6/12, 30 (44.1%) had 6/18 and 6/60 and rest 34 (50.%) had <6/60. This association was statistically significant, and a study conducted by Vudayana et al.,^[14] also found an association between pre-operative IOP and post-operative visual acuity. Few complications that were seen in cases of LIG were persistent edema, persistent rise in IOP either due to formation of PAS or failure of glaucoma filtration surgery, or glaucomatous optic atrophy. Therefore, a long-term follow-up was needed in these cases and in each follow-up BCVA, IOP measurement, visual field testing, as well as fundus examination should be done.

CONCLUSION

120 patients after taking informed written consent were enrolled in the study. The diagnosis of LIG was made based on clinical findings and investigations. The most common type was phacomorphic. The most common age group affected was between 61 and 70 years and in females. Initially, the patients were managed medically followed by surgery. The most common surgery performed was SICS/phacoemulsification with PCIOL. Patients were followed up to 4–12 weeks. At 1 week and the last follow-up, BCVA and IOP were taken. Delayed presentation leads to increased intraocular pressure, which in turn results in a worse visual outcome. Therefore, this study highlighted the characteristics of LIG and why early diagnosis, timely medical management, and surgery along with careful post-operative care and routine follow-up are essential, as it can result in good visual outcomes. More than 90% of cases were of phacomorphic and phacolytic type which develop in long standing cases of cataract. These cases were ignored for a long time, especially in old females from rural backgrounds as they were not properly aware of the importance of getting timely cataract surgery and avoid landing up into complications like LIG. The outcome of LIG management is good but as it has chronic nature and late complications such as synechial angle closure, glaucomatous optic atrophy, and failure of filtration surgery can occur, long-term follow-up is essential. A proper health education and awareness toward cataract in the general population, especially rural communities, are the need of the hour to prevent LIG. Various actions can be taken by our healthcare system and policymakers such as regular orientation and education sessions can be organized to encourage people to uptake services, camps in remote rural areas to bridge the gap between hospital and community, extra services such as free transportation, food, and accommodation to those who are disabled, poor, and needy. An educated and well-aware patient community can also aid the ophthalmologist in timely diagnosis, management, and post-operative care.