|Year : 2019 | Volume
| Issue : 4 | Page : 311-315
Bilateral juvenile open-angle glaucoma with keratoconus: A rare association and literature review
Vijayalakshmi A Senthilkumar1, Shiva M Krishna1, Manoranjan Das2, Komal Parin Sangoi2
1 Department of Glaucoma, Aravind Eye Hospital and Postgraduate Research Institute, Madurai, Tamil Nadu, India
2 Department of Cornea and Refractive Surgery, Aravind Eye Hospital and Postgraduate Research Institute, Madurai, Tamil Nadu, India
|Date of Submission||16-Oct-2019|
|Date of Decision||24-Oct-2019|
|Date of Acceptance||15-Nov-2019|
|Date of Web Publication||26-Dec-2019|
Dr. Vijayalakshmi A Senthilkumar
Department of Glaucoma, Aravind Eye Hospital and Postgraduate Research Institute, Madurai, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Juvenile open-angle glaucoma (JOAG) is a subset of primary open-angle glaucoma, which affects individuals aged 5 to 35 years. Keratoconus is a bilateral progressive ectatic disorder of the cornea that results in a reduction of vision due to irregular astigmatism. The exact cause and the underlying pathological mechanism are unknown, but both environmental and genetic factors are thought to contribute to the development of the disorder. The association between keratoconus and normal-tension glaucoma has been widely published in literature, whereas the association between keratoconus and JOAG has been reported rarely. This is the third case report pointing toward the possible association of juvenile glaucoma with keratoconus, which emphasizes the importance of thorough glaucoma evaluation among keratoconus patients.
Keywords: Corneal hysteresis, corneal thickness, juvenile glaucoma, keratoconus
|How to cite this article:|
Senthilkumar VA, Krishna SM, Das M, Sangoi KP. Bilateral juvenile open-angle glaucoma with keratoconus: A rare association and literature review. TNOA J Ophthalmic Sci Res 2019;57:311-5
|How to cite this URL:|
Senthilkumar VA, Krishna SM, Das M, Sangoi KP. Bilateral juvenile open-angle glaucoma with keratoconus: A rare association and literature review. TNOA J Ophthalmic Sci Res [serial online] 2019 [cited 2020 Jan 27];57:311-5. Available from: http://www.tnoajosr.com/text.asp?2019/57/4/311/273992
| Introduction|| |
Keratoconus is a progressive, bilateral, asymmetric ectatic corneal disease where visual loss occurs due to irregular astigmatism, myopia, and corneal scarring. While the cause is unknown, it is believed to occur due to a combination of genetic, environmental, and hormonal factors. Juvenile open-angle glaucoma (JOAG), similar to primary open-angle glaucoma, has an insidious onset, is usually detected late, and often presents with advanced optic nerve damage and high intraocular pressure (IOP) >40 mmHg. JOAG is usually transmitted in an autosomal dominant fashion and most commonly involves myocilin protein (previously known as trabecular meshwork inducible-glucocorticoid response protein). Here, we report with clinical presentation, the course of the disease, management, and 4-year follow-up of a 17-year-old girl diagnosed with JOAG and keratoconus.
| Case Report|| |
A 17-year-old female child presented to us in 2015 with gradual diminution of vision in both eyes (BE) for the past 2 years. The child was already diagnosed with glaucoma in BE at a local eye care center and was using fixed combination of brimonidine 0.2% and timolol 0.5% eye drops twice a day in BE for the past 6 months. There was no history of presence of any other ocular or systemic disorders; however, she had a strong family history of glaucoma, with her father being diagnosed with advanced glaucoma in BE and had undergone bilateral trabeculectomy with intraocular lens (IOL) at the age of 36 years.
At presentation, her best-corrected visual acuity (BCVA) in the right eye (RE) was 6/24 with no improvement with refraction and in the left eye (LE), it was 5/60 on Snellen's chart improving to 6/18 with −7.0 DS/−1.0 DC at 60°. IOP by Goldmann Applanation Tonometer was 42 mmHg in the RE and 38 mmHg in the LE. On slit-lamp biomicroscopy, anterior segment findings were normal except for developmental cataracts in BE. Dilated fundus examination with 90 D lens revealed advanced disc damage in BE with a cup-disc ratio of 0.9 and a pale neuroretinal rim [Figure 1]a and [Figure 1]b. Gonioscopy by Zeiss four-mirror goniolens showed Shaffer's Grade IV open angles in BE. Visual field analysis by 10-2 testing protocol in Humphrey field analyzer showed tubular fields in BE without involving fixation. A diagnosis of bilateral JOAG was made. The patient was initially managed medically by adding latanoprost 0.005% eye drops night only in BE and then underwent LE trabeculectomy with mitomycin C in 2015.
|Figure 1: (a and b) Fundus image of the right eye and left eye showing 0.9 cupping with a pale neuroretinal rim|
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On the first postoperative visit (day 18 postoperative), she presented with a sudden diminution of vision in the RE with pain, watering, and redness for 2 days. Examination of the RE under slit-lamp biomicroscopy revealed conjunctival congestion with diffuse corneal haze with edema of all the layers of the cornea with a very hazy view of the anterior chamber. The LE showed a diffuse bleb with developmental cataract. A diagnosis of stromal keratouveitis was made in the RE, which was treated with topical dexamethasone sodium phosphate 0.1% eye drops four times a day for 15 days. The LE was managed with routine postoperative medications including topical gatifloxacin 0.3%, prednisolone acetate 1% in tapering doses, and homatropine 2% twice a day for 15 days. On follow-up after 2 weeks, corneal edema had reduced in the RE, and cornea clinic expert opinion was sought. A diagnosis of acute hydrops in the RE was made based on the clinical examination, which was treated with topical sodium chloride 5% eye drops thrice a day for 1 month. Pentacam was not done during that visit as the child was very uncooperative in view of pain. Central corneal thickness (CCT) by ultrasonic pachymetry was RE −578 μ and LE −435 μ. It was decided to do pentacam in the next visit once the child was symptomatically better. However, the child was lost to follow-up. The patient then came to us in 2017. On examination, BCVA in the RE was 6/18 with −6.0 DS and in the LE, it was 6/18 with −2.5 DS/−4.0 DC at 17°. The RE showed a steep cornea with endothelial scarring, developmental cataract, and the LE showed a steep cornea and developmental cataract [Figure 2]. Pentacam and anterior segment optical coherence tomography (ASOCT) were also done. Pentacam confirmed keratoconus in BE, with the thinnest point being 437 μ in the RE and 431 μ in the LE. ASOCT RE showed corneal thinning, and the corneal thickness measured was 391 μ [Figure 3]. Spectral-domain optical coherence tomography of retinal nerve fiber analysis revealed superior and inferior quadrant thinning in the RE and gross thinning involving the macula in the LE [Figure 4]. Orbscan performed in 2019 in the RE showed sim K1 48.8 D at 167° and sim K2 48.1 D at 77°, with the thinnest point being 469 μ. The LE showed sim K1 54.8 D at 99° and sim K2 48.9 D at 9°, with the thinnest point being 377 μ [Figure 5]. In view of all these findings, a diagnosis of bilateral JOAG including advanced optic nerve damage, bilateral keratoconus, and acute hydrops in the RE and developmental cataract in BE was made.
|Figure 2: (a) Slit-lamp photograph of the right eye showing a steep cornea with deep anterior chamber with stromal haze. (b) Slit-lamp photograph of the left eye showing deep anterior chamber with psuedophakia and (c) avascular bleb|
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|Figure 3: (a) Vertical scan of anterior segment optical coherence tomography (ASCOT) right eye showing corneal thinning and irregularities in the Descemet's membrane. (b) ASOCT showing central stromal haze|
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|Figure 4: (a) Spectral-domain optical coherence tomography right eye reveals superior and inferior quadrant thinning (b) Left eye showing diffuse retinal nerve fiber layer thinning involving the macula|
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|Figure 5: (a) Orbscan with Quadmap right eye showing steep cornea of Kmax48.8 D, with the thinnest location of corneal thinning being 469 μ suggestive of keratoconus. (b) Left eye showing abnormality in all maps, with the thinnest location of Kmaxcorneal thinning being 377 μ suggestive of keratoconus|
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The patient was continued on brimonidine 0.2% + timolol 0.5% combination eye drops twice a day and latanoprost 0.005% eye drops night only dosing in the RE. The patient then underwent LE phaco with acrylic IOL in May 2018 followed by trabeculectomy with 5-flourouracil in the RE in 2019 [Figure 2]. Her postoperative course was uneventful. At 3-month follow-up, we could achieve a target IOP of 13 mmHg in the RE and 14 mmHg in the LE as measured by Goldmann Applanation Tonometer. BCVA on final follow-up was 6/12 in the RE with −7.0 DS and in the LE, it was 6/12 with −4.0 DC at 180°. She was advised regarding the need for deep anterior lamellar keratoplasty in the RE, but the patient was again lost to follow-up.
| Discussion|| |
Keratoconus is a progressive ectatic disorder of the cornea characterized by central and paracentral corneal thinning and protrusion. The first case series report highlighting the association of JOAG and keratoconus was reported by Sahil et al. in 2015, and the second case report was reported by Utyama et al. in 2019. Although the association between keratoconus and JOAG is not fully understood, both are linked in several ways. One of the major risk factors for the progression of glaucomatous damage is corneal thickness and corneal hysteresis (CH). As per the Ocular Hypertension Treatment Study, CCT is an important and independent risk for the progression of glaucoma in patients with ocular hypertension. Eyeball with thinner corneas and low CH becomes more elastic and is susceptible to IOP fluctuations, leading to rapid glaucomatous progression. Thickness of the lamina cribrosa has been reported to be less in highly myopic eyes with glaucoma and also in patients with thinner corneas. It is hypothesized that a thin lamina cribrosa with inadequate connective tissue support may be associated with glaucoma development. Furthermore, the association of keratoconus with normal-tension glaucoma has been widely reported in literature.
Although Goldmann Applanation Tonometry is the gold standard for IOP measurement in the clinical management of glaucoma, measurement errors may occur due to variation in CCT, axial length, and corneal curvature in patients with keratoconus. To decrease this bias, several authors believe that biomechanical and topographic evaluation of the cornea with ocular response analyzer (ORA) and pentacam can help in better understanding of IOP. ORA allows several IOP measurements including Goldmann-correlated IOP (IOPG) and cornea-compensated IOP (IOPCC). IOPCC is a more accurate indicator of true IOP than IOPG because it is less affected by corneal properties such as CCT and CH. Evaluation of the optic nerve in patients with keratoconus is challenging because of irregular astigmatism and corneal scarring.
| Conclusion|| |
This case report indicates the need of awareness among primary eye care providers regarding the coexistence of JOAG and keratoconus. In our patient, the diagnosis of keratoconus was missed during initial visits, and also the presentation of acute hydrops was misdiagnosed as stromal keratouveitis. All keratoconus patients with doubtful glaucomatous fundus changes should be thoroughly evaluated by glaucoma specialists. Early detection and appropriate treatment of glaucoma is important to prevent irreversible visual loss.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]