Case Report: The efficacy of early phacoemulsification in the intraocular pressure control in primary angle closure glaucoma associated with cataract in a young female [version 1; peer review: 1 approved, 1 approved with reservations]

Glaucoma is a leading cause of irreversible blindness in the world, second only to cataract. Among different types of glaucoma, irreversible bilateral visual impairment is more common in primary angle closure glaucoma (PACG) patients. PACG and cataract often coexist and are both more prevalent among the elderly population, being rare in children and young adults. Here, we discuss the case of a 39-year-old Caucasian woman with unilateral PACG associated with cataract. The patient presented with a several-day history of left sided headache, decreased and blurred vision as well as pain and redness of the left eye (LE). She reported similar episodes in the previous year. Visual acuity (VA) of the LE was limited to counting fingers and intra-ocular pressure (IOP) of the LE was 42 mmHg. Anterior segment examination of the LE revealed: edematous cornea, a peripheral anterior chamber depth corresponding to Van Herick’s grade 0, mid-dilated pupil and lens opacities with visible glaukomflecken. Gonioscopic evaluation revealed iridotrabecular contact for 360o, no visible angle structures and a flat–mild convex iris contour. The digital image of the optic disc suggested only a thinning of neuro-retinal rim at the lower pole. Following treatment of the initial symptoms, phacoemulsification with intra-ocular lens implant was performed. IOP improved and no IOPlowering medication was required. The patient was monitored for VA, IOP, field of vision changes, and optic disc evaluation every six months for 2 years and no glaucomatous change occurred. The patient also denied ocular symptoms during this period. This case supports the effectiveness of early phacoemulsification in the IOP control in patients with PACG. Open Peer Review


Introduction
Glaucoma is the second leading cause of blindness around the world, being prevalent in 3.5% in those 40 years and older. The number of people with glaucoma worldwide is expected to rise from 64 million to 76 million in 2020 and to 111 million by 2040, with Africa and Asia being affected more heavily than the rest of the world 1,2 . This disease is generally determined by damage to the optic nerve level as a result of abnormally high intra-ocular pressure.
With a particularly high prevalence among particular populations, primary angle closure glaucoma (PACG) is responsible for nearly half the glaucoma-related blindness in the world, despite being much less common than open angle disease 3 . PACG occurs as a result of an interruption in the physiological mechanism of aqueous outflow in patients with crowded anterior segment anatomy. Demographic risk factors include older age, female gender and Asiatic race 1 . Family history of glaucoma increases also the risk of developing the disease. Angle closure is rare in children and young adults, only isolated cases and small series, primarily composed of particular ethnicities, having been reported 4-6 .
PACG and cataract often accompany one another and are both more common among the elderly population. The crystalline plays a critical role in the pathogenesis of the two diseases because of its anatomical proximity with angle structures. Therefore, cataract extraction can be a viable solution for both conditions, because it can deepen the anterior chamber and mechanically open the iridocorneal angle, thus reversing the underlying process in these patients 7 .
We present a rare case of newly diagnosed PACG associated with cataract in a young female in order to underline the efficacy of early phacoemulsification in the control of intraocular pressure.

Case presentation
A 39-year-old Caucasian woman with a family history of glaucoma in one grandparent presented with a two-day history of left sided headache, decreased and blurred vision, as well as pain and redness of the left eye (LE). The patient reported multiple self-limited episodes of headache and pain of the LE associated with blurred vision with no apparent exacerbating factors during the previous year. She was not taking prescribed topical ocular or systemic medication and no ocular trauma was declared. Ophthalmological medical history revealed hyperopia of both eyes (right eye (RE) = +1.75 D sphere, LE = +3.75 D sphere).
On presentation, visual acuity (VA) of the LE was limited to counting fingers and intraocular pressure (IOP) of the LE was 42 mmHg (Goldmann Tonometry). Slit lamp examination of the left anterior eye segment revealed the following: conjunctival hyperemia, edematous cornea, relatively normal central anterior chamber (AC) depth, a peripheral AC depth corresponding to Van Herick's grade 0 and oval, asymmetric, poorly reactive and middilated pupil. Gonioscopic evaluation revealed iridotrabecular contact for 360°, no visible angle structures and a flat-mild convex iris contour. After indentation, the iris contour slightly changed. She was diagnosed with acute primary angle closure. Also, the patient was found to have cataract with visible glaukomflecken in the left lens. Due to corneal edema and lens opacities, fundoscopic examination of the LE was difficult to perform.
The VA of the fellow eye was 100/100 cc (with correction +1.75 D sphere) and IOP 16 mmHg. Anterior segment examination revealed a narrow peripheral AC depth corresponding to Van Herick's grade 2 and gonioscopic evaluation suggested no abnormality. The posterior segment was also normal.
After the resolution of the acute attack, gonioscopy of the LE revealed no anterior peripheral synechiae. Fundoscopic examination revealed the optic disc with a cup-disc ratio of 0.4. The other part of retina was normal. The digital image of the optic disc suggested only a thinning of neuro-retinal rim at the lower pole, leading to her diagnosis of PACG.
On the sixth day, biometry and of the LE was performed in order to plan cataract surgery (Table 1). A-scan biometry found the left lens thickness to be 4.21mm. The glaukomflecken could not be identified by anterior segment optical coherence tomography or ultrasound biomicroscopy. Endothelial cell count was in normal range. On the seventh day, the patient underwent uneventful phacoemulsification with an intraocular lens implant.
The day after surgery, the VA of the LE was 60/100 sc (without correction) and IOP was 17 mmHg. At discharge the VA of the LE was 80/100 sc (without correction) and the IOP was 13 mmHg. The patient followed the standard post-cataract surgery care (week 1 to 2: topical tobramycin/dexamethasone 3 mg/1 mg/ml 1 drop x4/day and topical bromfenac 0.9 mg/ml 1 drop x4/day, week 3 to 4: topical tobramycin/dexamethasone 3 mg/1 mg/ml 1 drop x2/day and topical bromfenac 0.9 mg/ml 1 drop x2/day).
At the six-week evaluation, VA of the LE was 100/100 sc (without correction) and IOP was appropriate. The field of vision investigated by automated perimetry (Humphrey) appeared normal.
The patient was monitored for VA, IOP, field of vision changes, and optic disc evaluation every six months for 2 years and no glaucomatous change occurred. She also declared no ocular symptom in all this period of time.

Discussion
A case with unilateral PACG associated with cataract in such a young patient with no systemic co-morbidities is an unusual presentation. The diagnosis of PACG was preferred, rather than simply primary angle closure, due to the modification of the neuro-retinal rim and the risk factors of the patient, including family history.
This case of unilateral PACG associated with cataract in a young patient with no systemic diseases underlines three aspects: the importance of the risk factors in glaucoma, the relationship between the pathophysiologic mechanisms of the two conditions, and the effectiveness of the phacoemulsification in the IOP control.
The etiology of angle closure in young people is different from that of the older population and is typically associated with structural or developmental ocular particularities: plateau iris, iridociliary cysts, nanophthalmos, etc. In the presented case, the patient had moderate hyperopia in the affected eye and low hyperopia of the fellow eye. Hyperopia is mentioned in literature as a risk factor for PACG 8 . There are, however, studies that did not find any statistically significant correlation between refractive error and PACG 9,10 . Biometrical parameters such as axial length and AC depth were strongly correlated with PACG 10 . The small axial length (AL) with a normal size lens or even growing lens, as it is in cataract, leads to a crowded anterior segment and a shallow anterior chamber 9 . Thus, the uni-laterality of the condition could be explained in part by the differences in the biometrical parameters between the eyes, the affected having lower values of these parameters. Also, the fellow eye is at risk of developing primary angle closure, and should be monitored.
Another particularity of the disease is the association between the two conditions at the time of diagnosis. The way in which PACG and cataract influence each other in a young patient could be explained, in part, by the presence of glaukomflecken composed of necrotic lens epithelial cells and degenerated subepithelial cortex. These two diseases seem to reinforce each other. Thus, on one side markedly elevated IOP in PACG determined epithelial and anterior cortical lens opacities, on the other side the affected lens growth can compromise the aqueous flow between the lens and iris at the pupil 11 . Therefore, the pupillary block suggested as a mechanism of PACG in older patients could as well appear, even though rare, in younger patient 4 .
Initial therapeutic approach consisted of IOP-lowering medication and, after resolution of the acute attack, phacoemulsification with intraocular lens implant. Iridotomy could have been another viable treatment option, but the presence of a cataractous lens dictated cataract extraction, which is demonstrated to have more favorable results in similar conditions, despite increased risk of corneal edema after phacoemulsification 12 . The patient's IOP improved, as it is also described in the literature in other cases, after cataractous lens extraction 12,13 . The patient required no IOP-lowering medication and the first 2 years follow up glaucoma revealed no other glaucomatous damage.

Conclusions
The therapeutic choice in PACG (iridotomy vs. phacoemulsification) should be guided by risk factors and the subsequent pathophysiological mechanisms. As our case of PACG associated with cataract in a young patient confirmed, early phacoemulsification proved its effectiveness in the IOP management. Although the risks of surgical approach are well known, especially increased risk of corneal edema, the benefits are undeniable: a good IOP control, decrease need for IOP-lowering drugs and a significant improvement of VA with a better quality of life for the patient.

Data availability
All data underlying the results are available as part of the article and no additional source data are required.

Consent
Written informed consent for the publication of this case report was obtained from the patient.