Distinct management of peripheral hypertrophic subepithelial corneal degeneration

Abstract

We report an atypical case of peripheral hypertrophic subepithelial corneal degeneration (PHSCD) managed with superficial keratectomy after 8 years of conservative treatment failure. A 34-year-old female presented with chronic bilateral foreign-body sensation, photophobia, and peripheral corneal opacities. The lesion was not extending to the visual axis or affecting visual acuity, unlike all the described cases in the literature. Initial management included lubricating drops and topical anti-inflammatory therapy, which failed to alleviate symptoms or stabilize the lesions. Slit-lamp and optical coherence tomography imaging revealed bilateral inferior peripheral subepithelial fibrosis without neovascularization. Superficial keratectomy was performed on the right eye to address her concerns about appearance and symptom persistence. Histopathology confirmed the diagnosis of PHSCD. Postoperative examination showed significant improvement in corneal appearance, peripheral thickness, and symptom relief with no recurrence at 2 months. The patient was scheduled for similar surgical management for the other eye. PHSCD is a rare, underreported corneal degeneration that may present with persistent symptoms unresponsive to medical management. Superficial keratectomy is an effective surgical option to restore corneal clarity and alleviate symptoms in advanced case. Further studies are needed to explore the disease’s etiology, risk factors, and long-term surgical outcomes.

INTRODUCTION

Peripheral hypertrophic subepithelial corneal degeneration (PHSCD) is an underreported disease entity which was first described in 2003 as a variant of Salzmann’s nodular degeneration (SND).[1] Then, clear diagnostic criteria according to the presence of certain signs and symptoms were prescribed in 2014 to help differentiate between both entities.[2] PHSCD is characterized by bilateral chronic subepithelial confluent perilimbal fibrosis between the epithelium and Bowman’s layer with thickening of the cornea peripherally, unlike SND which might present with scattered corneal opacification extending to the center.[2]

Usually, patients with PHSCD complain of foreign-body sensation, reduced vision, and dry eyes, as it is proven to be associated with decreased tear production and stability.[2,3,4] However, disease etiology is not well understood. Many hypotheses have been presented to explain this phenomenon, including chronic corneal surface irritation such as chronic contact lens use and dryness, chronic infections as well as chronic systemic diseases such as systemic lupus erythematosus, ocular traumas, and environmental hazardous exposures.[5] PHSCD mainly occurs in middle-aged females, with a prevalence of four times more than male groups.[5]

First-line management in PHSCD is conservative, mainly with lubricating drops and preservative-free artificial tears as needed. However, in more advanced cases where the lesions invade the visual axis, a surgical option with manual superficial keratectomy or phototherapeutic keratectomy with an excimer laser could be used.[5] Here, we are reporting a case of atypical chronic bilateral peripheral subepithelial corneal degeneration that has been progressing over 8 years. In contrast to the previously published literature, the lesion did not impair her vision, and she only required the surgical removal for cosmetic purposes.

CASE REPORT

A 34-year-old female presented to the cornea clinic complaining of bilateral chronic foreign-body sensation, photophobia, and related esthetic concerns for 8 years. She has been using various lubricating drops along that period with no significant improvement. However, there is no history of other topical drugs or gold salt use. She reported a long history of contact lens use for cosmetic purposes, but she discontinued their use 8 years ago after noticing the lesions. Otherwise, she has no other significant systemic or ocular history. Along the course of her history, she was managed medically with topical tacrolimus and fluorometholone eye drops tapering. However, the opacity was stable on imaging and no improvement of symptoms was noted. Then, after 8 months of follow-up, surgical management with superficial keratectomy for the right eye was suggested due to her concerns about the cosmetic appearance of her eyes.

On examination, her visual acuity was 20/20 in both eyes, and the intraocular pressure was stable on a normal range in all her visits.

Slit-lamp examination showed normal lid and conjunctiva bilaterally. She had inferior corneal whitish opacities between 4 and 8 o’clock in both eyes, as shown in Figure 1a and b; moreover, she had clear cornea centrally and peripheral inferior thickening with no superficial neovascularization noted [Figure 1c]. No ciliary injection, anterior chambers were deep and quite in both eyes. Pupils, lenses, and fundus examination were normal. She had normal corneal sensations in both eyes. Anterior segment optical coherence tomography (AS-OCT) of both corneas showed superficial subepithelial lesions without interruption of Bowman’s layer [Figure 2].

Figure 1.

The clinical appearance of both the eyes showing inferior corneal thickened opacification. (a) right eye, (b) left eye, (c) magnified slit photos of the right eye before the surgery

Figure 2.

Optical coherence tomography of the left cornea showing peripheral hypertrophic epithelium

She underwent superficial keratectomy for the right eye under local anesthesia. The lesion was peeled and dissected gently with the help of surgical microscope built-in optical coherence tomography (OCT) as one piece. Then, blade and pterygium burr were used to scrape the residual opacities and to smoothen the corneal surface [Video 1]. At the end of the surgery, a bandage contact lens was applied for 5 days. Figure 3a and b shows slit-lamp photos and OCT of the cornea 5 days postoperatively with significant improvement of the appearance and thickness peripherally, mild conjunctival injection, and no residual lesions left.

Figure 3.

(a) Postoperative slit-lamp photos and optical coherence tomography (OCT) of the right eye showing improved corneal clarity, uniform thickness, and healed epithelial defect; (b) Postoperative slit-lamp photos and OCT of the right eye showing improved corneal clarity, uniform thickness, and healed epithelial defect; (c) OCT of the left cornea 2 months postoperatively

Tissue histopathology showed irregular corneal epithelium, absent Bowman’s layer, and focal subepithelial fibrosis, which is suggestive of PHSCD. On the last visit, 2 months after the surgical removal, she showed improvement of corneal appearance and no recurrence; she was scheduled to undergo a similar procedure in the other eye [Figure 3c and 4].

Figure 4.

Appearance on the follow-up visit (2 months postoperatively)

DISCUSSION

PHSCD is a relatively newly described corneal dystrophy. PHSCD was primarily described by Maust and Raber on six patients case series, in which they described subepithelial circumferential hypertrophic lesions that are peripheral and bilateral in 81.6% of the reported cases.[1,5] In 2014, Petri J Järventausta et al. described PHSCD among 14 patients histopathologically as superficial superonasal fibrosis with adjacent neovascularization peripherally that led to thickening in that area of the cornea with flattening centrally, eventually leading to astigmatism.[2,3] In contrast to the previously described cases, our patient exhibited no neovascularization nor astigmatism, with distribution of the bilateral lesions inferiorly without skip areas.

Moreover, a case series done in Germany of nine patients, they found that majority of the cases had nasal and temporal lesions bilaterally. These predominant locations at the 3 and 9 o’clock positions supported their hypothesis of alignment with areas of light exposure, similar to the pathogenesis of pterygia. However, the exact timeline for the evolution of these lesions remains speculative.[6]

Patients with PHSCD typically present with a range of symptoms with varying incidence among multiple studies. Petri J Järventausta et al. reported that the most common symptom is reduced visual acuity (86%), followed by ocular surface disease symptoms, such as dryness or irritation (64%).[2] However, Gore et al. found that the majority of patients had ocular surface symptoms (45%) and decreased vision (18%).[7] Atypically, our patient’s major concern was cosmetic look, as her visual acuity was 20/20 without correction and no astigmatism was noted throughout the disease course.

Reduced visual acuity was mainly attributed to those patients who had astigmatism or lesions extending to the visual axis centrally.[5] While many patients with PHSCD experience symptoms, it is important to note that 14% may remain asymptomatic for a long time, often leading to misdiagnosis as SND.[1,7]

While the exact etiology remains unclear, several risk factors have been identified. Middle age, dry eyes,[4] chronic ocular surface inflammation and irritation by contact lenses, history of ocular trauma, and previous ocular surgeries are significantly associated with the development of PHSCD.[5] While some systemic autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus may be associated with PHSCD, the evidence is inconclusive.[5] For instance, a study by Maust and Raber included two patients with sarcoidosis and thyroid disease, but no definitive link was established between these conditions and PHSCD.[1]

Acquired corneal subepithelial hypertrophy (ACSH) is a recently identified corneal disease, distinct from but sharing similarities with PHSCD. It was first documented by Al-Rajhi et al. ACSH primarily affects males and typically manifests after corneal surgical procedures, such as penetrating keratoplasty (PK) and lamellar keratoplasty.[8,9] Although histopathology results were similar to those of patients with PHSCD, a case series involving three patients postcorneal surgery found the described lesion exclusively in the operated eyes.[9]

Moreover, various diagnostic tools are employed for PHSCD, many of which are continually evolving. Multiple organizations, including the American Academy of Ophthalmology (AAO), the European Society of Cataract and Refractive Surgeons, and the International Council of Ophthalmology, have published diagnostic guidelines for PHSCD.[5] Diagnosis begins with basic clinical examinations such as slit-lamp biomicroscopy and refractive error measurements, followed by serial evaluations to monitor disease progression.[5] Advanced imaging techniques, such as AS-OCT and in vivo confocal microscopy, further aid in accurate and early diagnosis. Differentiating PHSCD from other corneal lesions, such as corneal intraepithelial neoplasia and Terrien’s marginal degeneration, is crucial for appropriate management.[10]

Management options depend on the case and the disease stage. One report published in 2003 showed that patients presented with various complaints and were managed differently by topical lubrication, punctal occlusion, topical steroid therapy, oral doxycycline, and superficial keratectomy, However, all of their patients had stable disease progression on 30-month follow-up.[1] Nonetheless, our case was managed by topical anti-inflammatory and lubrication drops and followed up for multiple years with no improvement noted. Ultimately, surgical keratectomy was successfully performed.

Stepwise management approach started by conservative medical management with regular monitoring was recommended by the AAO.

Gore et al. identified specific criteria for surgical intervention, including ocular surface discomfort, progressive astigmatism, and involvement of the visual axis.[7] For refractory cases where medical management fails, surgical intervention may be necessary. Superficial keratectomy, a surgical procedure to remove areas of fibrosis, has been shown to be both effective and safe. For advanced cases with severe visual impairment or structural damage, a partial or full-thickness corneal transplant (PK) may be required.[5]

In conclusion, PHSCD is a relatively new corneal dystrophy that can significantly impact visual function and quality of life. While its exact etiology remains unclear, various risk factors have been implicated.

Early diagnosis and appropriate management are crucial for optimal outcomes. Conservative measures are often sufficient for mild cases. However, more advanced cases may require surgical intervention, including superficial keratectomy or corneal transplantation. Moreover, further research is needed to better understand the pathogenesis of PHSCD and subsequently enhance treatment strategies.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.