A Rare Case of Chronic Primary Angle-Closure Glaucoma in a Young Woman with Coexisting Pathologic Myopia

Introduction: Primary Angle-Closure Glaucoma (PACG) is usually present in adults older than forty and is more common in hyperopic eyes. Angle-closure is usually related to structural or developmental ocular abnormalities in young individuals. Case presentation: We presented a rare case of PACG in a 32 years old woman with pathologic myopia of -23.0 RLE. The chief complaint was blurring of the right eye three months before the visit. Right eye Intraocular Pressure (IOP) was 30mmHg-38mmHg despite treatment with three intra-ocular pressure-lowering agents. Axial length was 32.36 mm and 31.19 mm RLE. Anterior chamber depth was 2.36 mm and 2.60 mm RLE. Lens thickness was 5.07 mm and 5.40 mm RLE. Signs of GON and pathologic myopia were found in both eyes. GON was present asymmetrically (0.9 and 0.6 RLE), with the myopic crescent as well as baring and peripapillary atrophy. The optic disc was slightly tilted with the myopic crescent. There was also a marked sign of retinal pigment epithelium thinning and attenuation along with myopic chorioretinal atrophy. Conclusions: PACG in a young myopic individual is challenging to diagnose because myopia and glaucoma share similar optic nerve head pathology. Comprehensive examinations including gonioscopy, biometry, and OCT may confirm the diagnosis. In the presented case, angle-closure was caused by thick lenses and a shallow anterior chamber, along with excessively long axial length. Primary angle-closure at a young individual with myopic eyes is highly uncommon. Nonetheless, clinicians should always consider glaucoma even in the presence of high axial length and myopic fundus.


Introduction
Glaucoma is a degenerative eye condition that can lead to blindness, affects 3.5% of people aged forty and over. Adults over the age of forty are more likely to have Primary Angle-Closure Glaucoma (PACG). Females are more likely than males to develop PACG, and it is also more common in certain ethnic groups, such as Asian populations. PACG is found in around 17.14 million persons over the age of 40 worldwide, with a worldwide incidence of 0.6% (95% CI = 0.5-0.8%).
The global population [1] with PACG is expected to be 23.36 million in 2020 and 32.04 million in 2040, with Asia accounting for more than three-quarters of the PACG population. There are two types of PACG: acute and chronic. Primary Chronic Angle-Closure Glaucoma (PCACG) is more common in older people and is uncommon in young individuals. [2], [3] Diagnosing glaucoma in a highly myopic eye is a challenge as highly myopic fundus shares similar pathologic findings of glaucomatous optic neuropathy.
Myopic eyes are linked with a range of visual field abnormalities, and evaluating the cup-to-disc ratio in pathologic myopia with tilted optics will be exceedingly challenging. [4] Careful examination of anterior chamber structure and anterior chamber imaging modalities such as Anterior Segment-OCT is mandatory to define the diagnosis. https://e-journal.unair.ac.id/VSEHJ

Case presentation
A 32-year-old woman who came to the ophthalmology clinic at Dr. Soetomo General Hospital Surabaya presented with chief complaints of blurring right eye vision for about three months before the visit. The blurring of vision was worsening gradually over time.
She was also experience pain and redness in the right eye. The pain was said as worsen with eye movement.
The patient was already visit the ophthalmologist clinic with a medication history of twice a day brinzolamide and brimonidine tartrate eye drop, twice a day timolol maleate, and oral acetazolamide. With three intraocularpressure-lowering agents, right eye Intraocular Pressure (IOP) was never below 30mmHg. Visual acuity of the left eye was progressively worsening despite treatment.  In the right and left eyes, the optic disc had a cup-disc ratio of 0.9 and 0.5, respectively. Other Glaucomatous Optic Neuropathy (GON) signs, such as baring and peripapillary atrophy, were also present in both eyes. In the right eye, the optic disc was slightly tilted with the myopic crescent. There was also a marked sign of retinal pigment epithelium thinning and attenuation, giving the appearance of the tessellated fundus, also known as tigroid fundus. Myopic chorioretinal atrophy was seen in both eyes. Fundus photography was taken for documentation; unfortunately, the fundus photograph of the right eye was blurry due to a small pupil at examination ( Figure 9). The patient was diagnosed with primary angle closure glaucoma and pathologic myopia in both eyes. The intraocular-pressure lowering agent was continued with brinzolamide, brimonidine tartrate eye drop twice a day, timolol maleate twice a day, and oral acetazolamide twice a day. Goniosinechiolysis and peripheral iridectomy were planned for the right eye, and laser peripheral iridectomy subsequently for the left eye.

Discussion and conclusions
The case presented in this report is a chronic PACG in a young woman who also has pathologic myopia with extremely long axial length. Chronic PACG at a young age is a challenging case to diagnose and manage, as it needs lifelong follow-up and treatment. Angle-closure is rare in young adults; only isolated cases and small series have been reported. Several studies use the cut-off age of 40 years old to define young age angle-closure. It is used in the cut-off for presbyopia. [2], [5] Angle-closure in young patients is usually associated with structural or developmental ocular anomalies rather than relative pupillary block. [2]  Eyes that develop Angle-Closure Glaucoma tend to have crowded anterior segments and short axial length. [3], [6] The most important factors leading to the closure of the eye are shallow anterior chamber, thick lens, increased anterior lens curvature, a short axial length, small corneal diameter, and radius curvature. An anterior chamber depth of less than 2.5 mm is considered shallow enough to predisposes patients with primary angle closure.
In addition, Peripheral Anterior Synechia (PAS) formation increases in an anterior chamber depth of

OD OS
A B A B less than 2.4 mm. [3] In this case, the patient was 32 years old with angle-closure was caused by crowded anterior angle, shallow anterior chamber depth, and thick lens.
Anterior chamber depth was 1.58 mm for the right eye and 1.86 mm for the left eye (obtained using AS-OCT), and lens thickness was 5.07 mm for the right eye and 5.40 mm for the left eye (obtained using USG biometry).
There were discrepancies in the measurement of anterior chamber depth recorded by Ultrasound Biometry versus Anterior Segment-OCT. ACD obtained by anterior segment OCT measurement is considered more accurate because ultrasound devices can be distorted by operator experiences, US velocity setting, and lower resolution than optical devices. [7], [8] The patient, in this case, has a coexisting pathologic myopia at presentation, which makes fundus examination of glaucomatous optic neuropathy a bit challenging. because it was not significantly affected by refractive errors. [10] A further study conducted by Hsu, Chen, and Lin [4] in 2015 has shown that the ratio of GCC thickness to macular outer retinal thickness is not influenced by refractive error. They conclude that the ratio of GCC thickness to macular outer retinal thickness provides an accurate diagnosis of glaucoma in highly myopic eyes.
The most important point to define glaucoma in myopic eyes is the progression of optic nerve damage. Even in patients with disc and visual field findings that strongly suggest glaucomatous optic neuropathy, confirmation of progression is ultimately necessary to confirm the diagnosis of glaucoma. [11] Furthermore, myopia has been considered a risk factor for the progression of glaucoma. The mechanism of the increased susceptibility of myopia to glaucoma has not yet been fully elucidated. Several theories have been discussed. The theories explaining the association between myopia and glaucoma are the increased stress on the lamina due to the lengthening of the axial length.
Cahane and Bartov speculate that even with the same intraocular pressure, the scleral tension in the lamina of myopic eyes is greater than that of eyes with shorter axial lengths. Eye pressure may be higher with thinning of the sclera, which is a common morphological feature acquired in the area around the optic nerve head in very myopic eyes. [12] The initial treatments for PACG are to eliminate pupil  to lower the IOP. [14] Refractive surgery such as precise lens extraction may benefit high myopic eyes because the thick lens predisposes patients to angle-closure glaucoma. Lens extraction may have an IOP-lowering effect that ranges between 2 and 6 mmHg (up to 12 mmHg in one study) in eyes with PACG. [15] Removing a thickened and anteriorly positioned lens leads to restoring deeper angle configuration, which may be advantageous in eyes with PACG and leads to a significant IOP reduction. [15], [16] We planned surgical iridotomy with goniosynechialysis of the left eye for the initial treatment and prophylactic laser peripheral iridotomy of the left eye, along with careful observation of disease progression. Refractive surgery with precise lens extraction has been considered but is too risky to be immediately done because of the extremely shallow anterior chamber. Figure 9. Fundus Photography of (A) Right Eye, fundus photograph was blurry due to small pupil. IOP of the right eye was never below 30 mmHg that we were unable to dilate the pupil for better documentation; (B) Left eye fundus photograph shows marked retinal pigment epithelium thinning and attenuation, giving the appearance of the tessellated fundus, also known as the tigroid fundus, as well as myopic chorioretinal atrophy.
Primary angle-closure at a young age with myopic eyes is hugely uncommon. This case represents a rare finding of shallow anterior chambers with thick lenses predisposing high axial myopic eyes to angle closure.
Clinicians should always consider the possibility of angleclosure glaucoma even in the presence of high axial length and myopic fundus. History taking and examination may guide to the definitive diagnosis and treatment.