A Curious Case of Transient Myopia

By Ayeza Nadeem Butt, Noor Ul Ain, Tariq Shakoor, Laiba Asif

Affiliations

1. Department of Ophthalmology, Mughal Eye Hospital, Lahore, Pakistan

ABSTRACT
The authors report a case of transient myopic shift following acetazolamide administration for papilledema. A 37-year healthy male with no known comorbidities presented with bilateral transient blurring of vision. He was diagnosed with papilledema and treated with acetazolamide. Shortly after initiation, he developed an acute myopic shift, which resolved within one week of discontinuing the medicine. This case highlights that acetazolamide can induce transient acute myopia due to ciliary body effusion, often associated with anterior chamber angle narrowing. Similar cases were reported in patients using other drugs, including sulfa-derived diuretics, antiepileptics and antibiotics, which cause reversible ciliary body effusion. Clinicians should exercise caution during pupillary dilation in such patients, as it can precipitate angle closure glaucoma.

Key Words: Acetazolamide toxicity, Papilledema, Myopic shift.

INTRODUCTION

Advances in medical science have led to the development and widespread use of numerous pharmacological agents. Among them, acetazolamide, a carbonic anhydrase inhibitor, holds particular importance in ophthalmology, neurology, and general medicine. It is commonly prescribed as a diuretic for conditions such as congestive heart failure and raised intra- cranial pressure. Additionally, it is used in the prophylaxis of high- altitude sickness and in the management of various forms of glaucoma and optic disc swelling. Despite its therapeutic benefits, acetazolamide is associated with several adverse effects, including transient myopic shift following systemic administration.¹

Herein, the authors report the case of a 37-year male who developed a reversible myopic shift after oral acetazolamide was prescribed for papilledema.

CASE  REPORT

A 37-year male presented to the Mughal Eye Hospital, Lahore, Pakistan, with a one-day history of frequent, painless blurring of vision in both eyes, accompanied by the perception of a horizontal black line. He had no comorbidities, and his medical, surgical, ocular, and trauma history was unremarkable. There was no significant history of allergies or prior medicine use.

Figure 1: Two-dimensional coloured fundus photographs of the right and the left eyes, respectively, showing Grade 3-disc elevation.

On ophthalmic evaluation, detailed examination findings for both eyes are summarised in Table I. Fundus photography revealed bilateral grade 3 papilledema with marked optic disc elevation (Figure  1).

On further examination, the patient’s blood pressure (BP) was elevated at 190/110 mmHg. Antihypertensive therapy was initiated, in addition to topical non-steroidal anti-inflam- matory drugs and oral acetazolamide 250 mg four times daily. He was subsequently referred to a neurologist for further evaluation.

At the first follow-up one week later, his BP had improved to 140/80 mmHg. Optical coherence tomography (OCT) of the retinal nerve fibre layer (RNFL) demonstrated RNFL thickening, consistent with papilledema (Figure 2). Baseline investigations were within normal limits, and magnetic resonance imaging (MRI) of the brain and orbits was unremarkable. Oral acetazolamide was continued, and intravenous mannitol was administered. The neurologist also advised a lumbar puncture, which revealed a cerebrospinal fluid (CSF) pressure of 20 mmHg with normal CSF microscopy, cytology, and biochemistry. Subsequently, the patient reported decreased  vision  in  both  eyes.

Table I: Examination findings of the patient’s right and left eyes.

Examination	Right eye	Left eye
Best corrected visual acuity (logMAR)	0	0
Lids	Normal	Normal
Conjunctiva and sclera	Normal	Normal
Cornea	Clear	Clear
Anterior chamber	Formed and quiet	Formed and quiet
Intraocular pressure (mmHg)	17	18
Pupil reaction	Round, regular, and reactive	Round, regular, and reactive
Lens	Phakic and clear	Phakic and clear
Vitreous	Clear	Clear
Fundus	Grade 4 disc elevation, peripapillary splinter haemorrhages, and normal foveal reflex	Grade 4 disc elevation, peripapillary splinter haemorrhages, and normal foveal reflex

Table II: The refraction of the right and the left eyes pre-acetazolamide, post one-day treatment, and post six days’ discontinuation. Note the myopic shift that happened post one-day treatment with acetazolamide.

Refraction	Right eye	Left eye
Refraction pre-acetazolamide	logMAR 0 with plano	logMAR 0 with plano
Refraction post one day treatment	logMAR 0 with -1.50 DS/-0.50 DC ×40°	logMAR 0 with -1.25 DS/-0.50 DC ×40°
Refraction post six days discontinuation	logMAR 0 with -0.50 DS	logMAR 0 with -0.50 DS

Figure 2: Optical coherence tomography (OCT) of the retinal nerve fibre layer (RNFL) showing retinal thickening suggestive of papilledema in the right eye and RNFL thinning in the left eye.

Figure 3: (A) Visual field of the right eye within normal limits. (B) Visual field of the left eye: note the enlarged blind spot and centrocaecal scotoma and inferotemporal quadrantanopia in the left eye

The slit-lamp examination demonstrated a shallow anterior chamber, while applanation tonometry showed an intraocular pressure of 17 mmHg bilaterally. Notably, optic disc swelling had improved to grade 2. A transient myopic shift was documented during this period, as detailed in Table II, which compares refraction measurements before acetazolamide initiation, after one day of the treatment, and following six days of the medicine discontinuation. Oral acetazolamide was tapered, and the patient was advised to undergo visual field assessment.

At the subsequent follow-up, visual field testing revealed normal limits in the right eye (Figure 3A). In contrast, the left eye demonstrated an enlarged blind spot, a centrocaecal scotoma, and inferotemporal quadrantanopia, consistent with visual field defects secondary to papilledema (Figure 3B).

The patient’s unaided visual acuity improved to logMAR 0.2 in both eyes as the myopic shift subsided following the tapering of acetazolamide. After two weeks, unaided visual acuity returned to logMAR 0 bilaterally. Fundus examination demonstrated further resolution of disc oedema, improving to grade 1.

DISCUSSION

Sulphonamide medications are known to trigger distinctive ocular reactions, most notably transient myopia and acute angle-closure glaucoma.¹ The risk of such adverse effects is estimated at approximately 3%, with the underlying mechanism involving ciliary body effusion leading to forward displacement of the lens–iris diaphragm and subsequent refractive and angle changes.² Topiramate, a sulfa derivative used in migraine and seizure management, has been well- documented to cause acute myopia and angle-closure glaucoma. Similarly, indapamide, another sulphonamide-based medicine, has been reported to induce transient myopia associated with supraciliary effusion. Even a single 250 mg dose of acetazolamide has been shown to precipitate acute myopic shifts.³

Diagnosis is largely clinical, supported when available by ultrasound bio-microscopy, which can detect ciliary body swelling. Management is primarily supportive and centres on discontinuing the causative medication. If intraocular pressure remains elevated, additional interventions may be warranted, including topical pressure-lowering agents and systemic corticosteroids, or in refractory cases, surgical procedures such as trabeculectomy.

A review of the literature revealed similar presentations of acetazolamide-induced myopia. For example, a case was reported in 2020 involving an 85-year-old European woman with a history of posterior capsule opacification following uncomplicated phacoemulsification three years earlier.⁴ She underwent Nd:YAG capsulotomy and was prescribed oral acetazolamide post-procedure.

Within one day, she developed bilateral myopic shift with choroidal detachment. Vision improved, and the choroidal detachment resolved completely within one week after discontinuing acetazolamide and initiating topical steroids and cyclopentolate. Likewise, two cases involving middle-aged women were reported in association with hydro-chlorothiazide use, both of whom developed transient myopia.⁵ Following discontinuation of the medicine, all ocular changes resolved within approximately one week.

This case underscores the clinical significance of acetazolamide-induced myopic shift and associated anterior chamber angle narrowing. Ophthalmologists should remain vigilant regarding the potential adverse ocular effects of sulphonamide derivatives. Patients initiated on these agents should be closely monitored, managed cautiously during pupillary dilation, and appropriately counselled regarding possible visual disturbances.

PATIENT’S CONSENT:
Informed consent was obtained from the patient to publish the data concerning this case.

COMPETING INTEREST:
The authors declared no conflict of interest.

AUTHORS’ CONTRIBUTION:
ANB: Conception and design of the article.
NUA: Drafting and revision of the manuscript.
TS: Training supervisor.
LA: Discussion and references.
All authors approved the final version of the manuscript to be published.

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