Thyroid eye disease (TED), also called Graves orbitopathy, is the most common eye-related complication of Graves disease. In simple terms, the body's own antibodies stimulate fibroblasts in the orbit. These cells produce hyaluronan, which holds water, and some become fat cells. The extraocular muscles and orbital fat swell, but the bony orbit cannot expand, so the eye is pushed forward (proptosis), the lids swell, and the veins draining the orbit are squeezed. Disease activity is scored with the 7-point Clinical Activity Score (CAS), and severity is graded using EUGOGO criteria. TED can threaten vision. In a study of 106 patients from India, 22.6% had active disease and 7.5% had sight-threatening disease. This is accompanied by raised IOP. Swollen muscles press on the globe and venous congestion raises episcleral venous pressure, so IOP rises, especially on upward gaze. Raised IOP was found in 4.8% of 482 patients with Graves orbitopathy in the Netherlands. Angle-closure disease is also common in India: in a large tertiary study, primary angle-closure glaucoma made up 49.4% of all angle-closure disease, and LPI opened the angle in 63.4% to 95.9% of eyes, depending on the disease stage. Corticosteroids, the main treatment for active TED, can raise IOP in susceptible eyes. We report a woman in whom the orbit, a narrow angle and steroid treatment all threatened the optic nerve, and describe how her IOP fluctuated over 89 days with probable explanation in the discussion section below.

History: A 52-year-old woman came to the ophthalmology outpatient department with swelling of both eyelids for 7 months, and redness and watering with discharge for 10 days. She had been diagnosed with thyroid disease in July 2025, so the swelling began about 5 months after the thyroid diagnosis, and her thyroid treatment had been changed shortly before this visit. She was a known hypertensive since 20 years. Due to her earlier IOP peaks of 31 and 42 mmHg, she was already on maximum medical therapy, using four antiglaucoma medications (AGM) in both eyes: a brimonidine–timolol combination, pilocarpine, dorzolamide and travoprost. Visual fields done were within normal limits. Ocular examination: Visual acuity, IOP and other findings at presentation are shown in Table 1. Both eyes had periorbital puffiness and proptosis, and the CAS was 2/7 at presentation. By day 11 the right eye showed eyelid oedema, conjunctival and caruncular congestion and pain behind the eye (CAS 4/7). Extraocular movements were full and the pupils reacted normally. The lenses were clear and the optic discs were healthy with a cup-disc ratio of 0.1–0.2 in both eyes. The gonioscopy showed occludable angles in both eyes. Table 1. Findings at presentation (day 0) Parameter Right eye Left eye Spectacle correction +2.00 DS, add +2.00 +1.75/+0.75 × 40°, add +2.00 Unaided visual acuity 6/18 6/12P Best-corrected visual acuity 6/9 6/9p IOP on AGM, Goldmann applanation (mmHg) 18 20 IOP, iCare rebound (mmHg) 12 18 IOP, iCare rebound in upward gaze (mmHg) 20 26 Central corneal thickness in micrometre 550 560 Hertel exophthalmometry 22 mm 20 mm MRD 1 and MRD 2 0.5 mm 0.5mm Ocular motility Full and free Full and free Gonioscopy Occludable angles Occludable angles Optic disc Cup-disc ratio 0.1–0.2 Cup-disc ratio 0.1–0.2 Humphrey visual field (SITA Fast) VFI 100%, MD 0.07 dB, PSD 2.96 dB VFI 100%, MD 0.57 dB, PSD 2.57 dB Figure 1. Hertel exophthalmometry and IOP in upward gaze A. Hertel exophthalmometry B. IOP in upward gaze (Sattler sign) Legend: A, Hertel exophthalmometry. B, IOP measured with the iCare tonometer in upward gaze, which rose in both eyes (Sattler sign). Faces were blurred to protect identity. The working diagnosis was bilateral thyroid eye disease with primary angle closure (PAC), on maximal medical therapy. She was referred to the oculoplasty clinic and bilateral LPI was planned. Signs of thyroid ophthalmopathy present in this case: Dalrymple sign (retraction of the upper eyelid), Enroth sign (oedema of the lower lid), Stellwag sign (incomplete or infrequent blinking), Goldzeiher sign (deep injection of the bulbar conjunctiva), Sattler sign (increased IOP on upward gaze), Vigouroux sign (eyelid fullness) and Kocher sign (increased retraction with fixation) (Figures 1 and 2). Signs not seen: Joffroy sign (loss of forehead wrinkling on upward gaze), Jellinek sign (hyperpigmentation of the superior eyelid folds) and Hertoghe sign (loss of the lateral third of the eyebrow). Figure 2. Clinical photographs showing the signs of thyroid eye disease A. Frontal view B. Lateral view C. Downward gaze D. Upward gaze E. Conjunctival congestion Legend: A and B, frontal and lateral views showing Dalrymple, Enroth, Stellwag, Vigouroux and Kocher signs. C, downward gaze. D, upward gaze, showing absence of Joffroy and Hertoghe signs. E, conjunctival congestion (Goldzeiher sign). Faces were blurred to protect identity. Investigations Table 2. Thyroid profile (ECLIA, serum) Test Result Reference range Interpretation Total T3 1.19 ng/mL 0.80–2.00 Normal Total T4 5.37 µg/dL 5.10–14.10 Normal TSH 0.35 µIU/mL 0.27–4.20 Normal Anti-TPO antibody <0.25 Positive if >9 Negative The patient was therefore euthyroid on her current thyroid treatment. Humphrey visual field. Done 17 days before presentation and on day 98 with the SITA Fast strategy. Average values of both the tests - Mean sensitivity was 28.42 dB (right) and 28.48 dB (left), mean deviation 0.07 dB and 0.57 dB, and pattern standard deviation 2.96 dB and 2.57 dB. The visual field index was 100% in both eyes. Reliability was good: false negatives 0/1 (right) and 0/4 (left), and false positives 0/0 (right) and 0/2 (left). MRI of both orbits. Pre-septal and post-septal oedema around both orbits, involving both lacrimal glands, with raised signal intensity and thickening of the muscle bellies of the extraocular muscles. The possibilities raised were thyroid orbitopathy and orbital pseudo-inflammatory disease. Colour vision:Ishihara testing was normal in both eyes (17/17) in many visits. OCT retinal nerve fibre layer (RNFL):Done on day 89 (Figure 4). The average RNFL thickness was 88 µm in the right eye and 87 µm in the left eye, within normal limits, with 88% symmetry. The rim area was 2.09 and 1.98 mm² and the vertical cup-disc ratio 0.35 and 0.27. The macular cube showed normal thickness: central subfield 244 µm (right) and 232 µm (left) and cube volume 9.4 mm³ in both eyes. Central corneal thickness: About 550 µm in the right eye and 560 µm in the left eye, within normal limits. Gonioscopy. Occludable angles in both eyes, examined without and with indentation. Anterior segment OCT (ASOCT): Done on day 98 to assess the position of the lens and the mechanism of angle narrowing. The angle opening was 17° and 12° on the two sides of the scan in the right eye and 15° and 19° in the left eye, so all four angles were narrow (about 20° or less). Impression - bilateral primary angle closure with persistently narrow angles despite a patent iridotomy, a shallow anterior chamber and an iris lying close to the anterior lens surface. This points to a non-pupillary-block mechanism (plateau-like iris configuration and/or lens-related crowding) rather than pupillary block alone. With normal RNFL and visual field , this is best classed as PAC rather than established PACG. B-scan ultrasonography: Thickening of the medial rectus muscle belly was seen (Figure 3B). Clinical images Figure 3. Slit-lamp photograph after laser peripheral iridotomy and orbital B-scan A. Slit-lamp photograph B. B-scan of the orbit Legend: A, slit-lamp photograph of the anterior segment after laser peripheral iridotomy, showing a patent iridotomy. B, B-scan showing thickening of the medial rectus muscle belly. Management and clinical course The aim was to keep IOP safe, calm the orbital inflammation, and protect the optic nerve. Table 3 explains each step in plain terms, and Table 4 gives the course over time. Table 3. Treatment and the reason for each step Treatment Reason Four antiglaucoma drops continued They were already needed to hold IOP down after earlier peaks of 31 and 42 mmHg. Nd:YAG laser peripheral iridotomy, right eye (day 2) and left eye (day 5) A tiny hole in the iris lets fluid pass to the front of the eye. This relieves the narrow angle and lowers the risk of angle closure glaucoma, which orbital congestion and steroids can provoke. Loteprednol steroid drops for a week after each laser Settles the inflammation caused by the laser. Weekly intravenous methylprednisolone (IVMP), advised on day 11: 500 mg doses first, then 250 mg doses from day 53 Reduces active orbital inflammation, reducing swelling and muscle size. This is the first-line treatment for moderate-to-severe active TED, usually given weekly for 12 weeks. The third dose is recorded on day 25 and the tenth on day 74. Oral acetazolamide 250 mg, short courses (days 14, 74, 77 and 82) Lowers IOP quickly during spikes. Topical antibiotics (day 14) and lubricants Treated surface infection and relieved dryness and discharge. Antiglaucoma drops stepped up (day 82) and review in 2 weeks IOP was still 28/24 mmHg on applanation. Oculoplasty referral and thyroid care continued TED is best managed by a team. Table 4. Timeline Day Event IOP (RE / LE), mmHg BCVA (RE / LE) Treatment change 0 Presentation; occludable angles in both eyes 30/ 28 6/9 / 6/9p Pilocarpine 2% four times daily; oculoplasty referral 2 Laser iridotomy, right eye 20/30 6/9p / 6/9 Loteprednol drops, right eye 5 Laser iridotomy, left eye 13 / 14 6/9p / 6/9 Loteprednol drops, both eyes 11 Right eye CAS 4/7; IVMP advised 23 / 22 6/12 / 6/12 (unaided) IVMP counselling and booking 14 Redness, discharge, blurred vision 32 / 33 6/12 / 6/12 (unaided) Antibiotic ointment and drops; acetazolamide for 5 days 18 IVMP 500 mg dose recorded 17 / 19 6/12 / 6/12 (unaided) Weekly IVMP continued 39 Review 22 / 17 6/9 / 6/6-2 IVMP continued 74 10th IVMP dose 33 / 30 6/6p / 6/6p Acetazolamide for 3 days; IVMP 250 mg 82 Review; applanation tonometry 28 / 24 6/6p / 6/6p Antiglaucoma drops stepped up; acetazolamide for 1 week 89 Review; applanation tonometry 22 / 18 6/9 / 6/9p Drops continued; review in 2 weeks 112 Review; pressure and congestion settled 17 6/6 Antiglaucoma drops stepped down Figure 5. Highest IOP at each visit up to the latest review (day 112) Legend: highest of the iCare and Goldmann readings at each visit. The dashed line marks 21 mmHg. IVMP, intravenous methylprednisolone; LPI, laser peripheral iridotomy. Diamond, latest review (day 112, 5 November 2026): 17 mmHg after antiglaucoma medication was stepped down. The first spike (day 14) came during active inflammation, at the time IVMP was booked. The later spikes (days 74 and 82) came during the period of 250 mg doses. At the latest review (day 112, 5 November 2026), vision was 6/6 and IOP was 17 mmHg. The antiglaucoma medication was stepped down as the pressure and the congestion settled.

In this patient, the IOP rose and fell over three months despite medication and laser iridotomy, while vision, colour vision, the optic discs, RNFL, visual field and macular thickness stayed normal . Table 5. Signs of thyroid eye disease: earlier studies and this patient Sign Reported in the literature This patient Eyelid retraction Most frequent sign: 108 of 120 patients (about 90%) in a population-based cohort Dalrymple and Kocher signs present Eyelid and soft-tissue signs Eyelid signs in 51.2% and orbital signs in 87.7% of hyperthyroid patients in an Indian series of 106 patients Enroth, Vigouroux, Goldzeiher and Stellwag signs present; CAS 2/7 at presentation and 4/7 in the right eye on day 11 Proptosis 62% (73 of 120) Hertel 22 mm (right) and 20 mm (left) Restrictive myopathy 43% (51 of 120) Motility full, but medial rectus thickening on B-scan and IOP rise on upgaze (Sattler sign) Raised IOP 4.8% of 482 patients; in 33 patients with a thick inferior rectus, IOP rose from 16.8 mmHg in primary gaze to 25.7 mmHg on upgaze Peak 33 mmHg in primary gaze despite four drugs; 38 (right) and 34 mmHg (left) on upgaze Optic neuropathy 6% (7 of 120); sight-threatening disease in 7.5% of an Indian series None: BCVA 6/9 or better, normal colour vision, healthy discs, normal RNFL Dynamic IOP variation – there are multiple mechanisms influencing the intra ocular pressure. The table below helps us understand the same. Table 6. What are the mechanisms of IOP fluctuation in TED and what were there in this patient. Mechanism Explanation In the patient Restrictive myopathy (tight muscles) Thick, tight muscles press on the eye when it looks up, so IOP rises on upgaze IOP 38 and 34 mmHg on upgaze; muscle thickening on MRI; medial rectus thickening on B-scan Raised episcleral venous pressure Congested orbital veins raise the pressure in the veins that drain fluid from the eye, so fluid leaves less easily even when the angle is open Eyelid and conjunctival congestion; episcleral venous pressure was not measured Open-angle mechanism or steroid response The drainage meshwork itself may drain poorly, and steroids can make this worse in susceptible eyes Loteprednol drops and IVMP were given; spikes on days 74 and 82 came during IVMP Angle closure The iris is pushed against the drainage angle and blocks it Occludable angles on gonioscopy; narrow angles (12° to 19°) on ASOCT; earlier IOP peaks of 31 and 42 mmHg Discrepancy between rebound and applanation The rebound (iCare) and applanation readings differed several times in this patient. On day 77, iCare gave 16/19 mmHg and Goldmann gave 22/20. On day 82, iCare gave 22/23 and Goldmann gave 28/24. We therefore based treatment decisions on Goldmann readings. Central corneal thickness was normal (about 550 and 560 µm), so thick corneas did not explain the high readings. In one study of inactive thyroid-associated orbitopathy, iCare and Goldmann readings agreed closely, so the difference is not a general feature of TED. Corneal biomechanics (hysteresis and corneal resistance factor) also influence tonometer readings. Active inflammation, steroid treatment and the timing of each reading may also have contributed. The explanation therefore remains open and needs to be explored in future studies. Treatment. LPI was done first to protect the angle, as angle-closure disease is common in India. IVMP is the first-line treatment for active moderate-to-severe TED. The standard course is 500 mg weekly for 6 weeks, then 250 mg weekly for 6 weeks, and her schedule followed this pattern. Short courses of acetazolamide controlled the IOP spikes. Strengths • Serial IOP was recorded at 19 visits over 89 days, with both rebound and applanation readings. • Baseline vision, colour vision, optic discs and visual field were documented, so any later damage can be judged from them. • Thyroid profile, antibody test and MRI of the orbits supported the diagnosis. • The case shows how IOP can behave when TED, angle closure and steroids occur together in an Indian patient. Stepwise plan First, laser peripheral iridotomy, which was done. Second, if the angle stays narrow and the IOP stays high on drops, clear lens extraction: in the EAGLE trial, patients aged 50 years or older with a clear lens and angle closure had better quality of life and lower IOP after lens extraction than after iridotomy. Third, trabeculectomy if the IOP is still not controlled. The timing of surgery should take TED activity into account. In this patient the ASOCT showed that the angles stayed narrow although the iridotomy was patent, so a further laser is unlikely to help and she appears to have reached the second step: if the IOP stays high on drops, clear lens extraction (timed to TED activity) is the next option, with trabeculectomy kept in reserve. Consent to publish: Written informed consent for publication of the clinical details and accompanying images was obtained from the patient. A copy is available with the corresponding author. Author contributions: First and second authors were involved in the clinical care of the patient, the conception of the report, and the drafting and critical revision of the manuscript. Third and fourth authors reviewed and enhanced the manuscript. Conflicts of interest: There are no conflicts of interest. Financial support and sponsorship: Nil.

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