Spontaneous corneal hydrops and perforation in keratoconus and pellucid marginal degeneration

PURPOSE: To report two cases of pellucid marginal degeneration and one case of keratoconus associated with spontaneous corneal hydrops leading either to perforation or imminent perforation, requiring urgent keratoplasty. METHOD: Retrospective interventional case series of three patients with noninflammatory peripheral corneal degenerations. A retrospective review was done of the clinical courses, surgical interventions, and pathologic specimens, development of spontaneous hydrops, perforation, need for surgical intervention, and final visual outcome. RESULTS: Two patients with pellucid marginal degeneration and one with keratoconus developed spontaneous hydrops followed by aqueous leakage through markedly thinned anterior stroma. In one case, the leak site was successfully sealed after three separate applications of tissue adhesive, although the remaining two cases required penetrating keratoplasty. CONCLUSIONS: These cases document the very unusual occurrence of corneal hydrops leading to spontaneous corneal perforation in patients with keratoconus and pellucid marginal degeneration.     

Acute spontaneous corneal hydrops in a patient with pellucid marginal corneal degeneration

Pellucid marginal corneal degeneration (PMCD) is an ectatic corneal disorder characterized by a peripheral, noninflammatory band of thinning of the inferior cornea. This condition often is misdiagnosed with keratoconus, with which it shares several clinical, videotopographic, and histologic aspects. Furthermore, as with keratoconus, hydrops and spontaneous corneal perforation can occur. We report the case of a 56-year-old man with confirmed PMCD, emphasizing the diagnostic approach, the disease follow-up, and its complication in spontaneous acute corneal hydrops. Finally, regarding this case, authors collect the clinical and videotopographic characteristics of PMCD and discuss the different therapeutic options.     

Corneal perforation during scleral indentation in a patient with pellucid marginal degeneration

An observational case report of corneal perforation following scleral indentation in a patient with previously undiagnosed pellucid marginal degeneration is presented. Clinical examination, investigations, and subsequent management of this unwarranted and rare complication are described and discussed. The case highlights the need for thorough anterior segment examination before indirect ophthalmoscopy particularly in the presence of ectatic corneal pathology in which case scleral indentation should be avoided.     

Acute pellucid marginal corneal degeneration

Pellucid marginal corneal degeneration is a bilateral disease characterized by a narrow band of corneal thinning localized 1-2 mm from the inferior limbus. The disease is diagnosed usually between 20 and 50 years of life, and its etiology remains obscure. During the clinical course and evolution of pellucid marginal corneal degeneration, acute hydrops with corneal edema in the lower half may develop (acute pellucid marginal corneal degeneration). However, since cases of acute pellucid marginal corneal degeneration are not frequently encountered in clinical practice, each new patient is evaluated and managed with the utmost care to contribute to our better understanding of this disease. This is a report of two cases of acute pellucid marginal corneal degeneration that had a relatively favorable functional outcome when treated medically, so that corneal grafting was not necessary.     

Superior pellucid marginal corneal degeneration

PURPOSE: To report the clinical features and topographic findings of superior pellucid marginal corneal degeneration (PMCD). METHODS: Retrospective chart review of 15 eyes of eight patients of superior PMCD. Detailed history, visual acuity at presentation, degree of astigmatism, slit-lamp examination findings, topographic features, and Orbscan findings were noted where available. Improvement in visual acuity with spectacles or contact lens correction, surgical procedure if any, and final visual acuity were analysed. RESULTS: In all, six patients were males and two were females. All cases except one were bilateral. The patients ranged in age from 18 to 48 years. All cases had isolated superior PMCD. One patient was a diagnosed case of vernal keratoconjunctivitis. The visual acuity at presentation ranged from hand motions to 20/25. The degree of thinning varied from 30 to 90%. The extent of thinning was commonly seen between the 10 and 2 o'clock positions. Ectasia was seen below the site of thinning in all the cases of superior PMCD. Topographic features including vertical corridor of reduced power, against-the-rule astigmatism and superior loop cylinder were seen in 10 eyes. Orbscan was carried out in two eyes of one patient and revealed an area of increased elevation in relation to the best-fit sphere superiorly corresponding to the area of ectasia in both the eyes. The visual acuity improved with rigid gas-permeable contact lens in six eyes and the final visual acuity ranged from 20/400 to 20/30. Two eyes were subjected to surgical intervention (peripheral annular graft=1 and lamellar graft=1). CONCLUSIONS: PMCD can occur superiorly. It should be considered in the differential diagnosis of superior ectatic disorders. The topographic findings, of reduced power in the vertical meridian and superior loop cylinder, are typical of superior pellucid marginal degeneration. Visual rehabilitation is usually possible with contact lenses, with surgical management required in selected cases.     

Deep corneal scarring in pellucid marginal corneal degeneration.

Crescent-shaped, deep corneal scars were observed in seven (39%) of 18 patients with pellucid marginal corneal degeneration. The scars most likely represent a degenerative change related to the precipitous alteration in curvature of the cornea in that area.     

Management of pellucid marginal corneal degeneration

PURPOSE: This study was designed to determine how patients with pellucid marginal corneal degeneration (PMCD) are managed in a tertiary corneal practice. METHODS: A retrospective chart review of 45 patients with PMCD from a corneal referral practice was performed. Information collected from the medical records included demographic data, best-corrected visual acuity, videokeratography, contact lens use, and surgical procedures. RESULTS: Forty-five patients (85 eyes; 30 males, 15 females) with PMCD were included in this study. They were followed-up for an average of 4.7 years (standard deviation (SD), +/-8.7). Seventy-five eyes (88.2%) were managed nonsurgically with spectacles in 31 eyes (36.4%) or contact lenses in 44 eyes (51.8%). Contact lens management was initially attempted in 51 eyes (60%); however, 7 eyes failed contact lenses. Visual acuity of 0.5 (20/40) or better was noted in 34 eyes (75.5%) after contact lens fit. Ten eyes (11.8%) underwent penetrating keratoplasty with an average postoperative follow-up of 9 years (SD, +/-8.2; 1.5-20.5). Clear grafts were present in all 10 eyes at the end of the study (average, 9 years; SD, +/-82). CONCLUSIONS: Nonsurgical management of PMCD continues to play a predominant role in the management of this disorder. Poor best-corrected visual acuity at presentation of 0.2 (20/100) or worse and long follow-up (8 years or more) were significantly associated with surgery.     

Epikeratoplasty for pellucid marginal corneal degeneration

Two patients with advanced pellucid marginal corneal degeneration (PMCD) received bilateral epikeratoplasty grafts ranging in diameter from 9 to 12 mm. Corneal astigmatism was greatly reduced in every case and the possibility of resuming contact lenses for daily wear, obtained after surgery, provided patients with a satisfactory best corrected visual acuity. Peculiarities of surgical procedure and clinical experience are reported.     

Acute hydrops in pellucid marginal corneal degeneration

Three patients had pellucid marginal corneal degeneration complicated by corneal edema. The corneal edema appeared to be a result of a break or detachment of Descemet's membrane as a result of increasing corneal ectasia. The disruption in Descemet's membrane began just above the inferior, crescent-shaped area of stromal thinning. Therapeutic modalities initially included hypertonic solution to determine whether corneal edema would resolve spontaneously, apparently by endothelial migration with healing over the break in Descemet's membrane. One patient required thermokeratoplasty and another penetrating keratoplasty for persistent stromal edema. Acute hydrops can occur with pellucid marginal corneal degeneration by a pathogenesis similar to other noninflammatory corneal thinning disorders such as keratoconus.     

Acute corneal edema in pellucid marginal degeneration or acute marginal keratoconus

This article reports a case of bilateral corneal pellucid marginal degeneration. The right cornea had an acute hydrops. Both eyes underwent penetrating keratoplasty. A histopathological study of the corneal specimens was performed by light and electron microscopy. The histological changes observed on the right cornea showed breaks on Bowman's layer, edema and disorganization of the stromal collagen, and break of Descemet's membrane. The ultrastructural changes were similar to those observed in acute keratoconus, leading to the belief that these two corneal diseases are closely related.     

Long-term results after perforating corneo-scleroplasty in a case of acute unilateral superior pellucid marginal corneal degeneration

PURPOSE: This case report shows the long-term results after perforating corneo-scleroplasty in a rare case of superior pellucid marginal corneal degeneration with acute hydrops due to rupture of Descemet's membrane. PATIENT: In the left cornea of a 20-year-old patient with peripheral stromal thinning from 9 to 3 o'clock a rupture in Descemet's membrane occurred followed by lamellar splitting of the mid-stromal region. Due to the decrease in visual acuity and pain from corneal edema a surgical treatment was performed consisting of a perforating/lamellar corneo-scleroplasty protecting the anterior chamber angle. RESULTS: The status has remained stable for 17 years after surgery with nearly clear graft, best corrected visual acuity of 0.8 and no signs of recurrence or progression of the disease. Central astigmatism is regular, the endothelial cell count is 1250/mm2 in the central cornea, the central corneal thickness is 540 microm and only a mild vascularised superficial pannus and slight opacities in the predescemetal layer of the graft are found. There are no anterior synechia. On the right eye visual acuity is 0.8 due to slight amblyopia. There are no corneal changes which would indicate bilaterality of the disease. CONCLUSIONS: Our findings must be interpreted as an atypically localised superior pellucid marginal corneal degeneration with rupture of Descemet's membrane followed by acute corneal hydrops. When reduction of visual acuity or pain occurs a surgical treatment by perforating/lamellar corneo-scleroplasty can be performed stopping the progression of the disease and achieving a stable optical rehabilitation and absence of pain even after decades.     

Lamellar crescentic resection for pellucid marginal corneal degeneration

PURPOSE: To evaluate the results of lamellar crescentic resection in pellucid marginal corneal degeneration. METHODS: Patients with pellucid marginal corneal degeneration who underwent lamellar crescentic resection from 1995 to 2000 at Labbafinejad Medical Center were assessed. Diagnosis was based on clinical findings of slit-lamp microscopy and confirmed by corneal topography and pachymetry. RESULTS: Fifteen eyes of nine patients (six male and three female) were operated. Mean patient age was 32 years (range 25 to 41 yr). Preoperatively, best spectacle-corrected visual acuity was 20/200 to 20/500 with a range of 12 to 26 D of against-the-rule astigmatism (mean 19.00 D). Follow-up ranged from 13 to 57 months (mean 35 mo). Postoperatively, patients had with-the-rule astigmatism: mean 16.00 D at 6 weeks and 10.50 D at 6 months. In the second postoperative year, mean with-the-rule astigmatism was 4.30 D. Best spectacle-corrected visual acuity was 20/40 in 71% of eyes at final follow-up. No significant complications occurred during the study period. CONCLUSION: Lamellar crescentic resection was a safe and effective non-penetrating surgical method to manage pellucid marginal corneal degeneration, however, visual recovery was relatively prolonged.     

Successful conservative management of hydrops with perforation in pellucid marginal degeneration

CASE REPORT: Hydrops with perforation in the setting of pellucid marginal degeneration is a rare complication that is generally treated surgically. We report the first case of successful nonsurgical management using only a bandage contact lens. COMMENTS: Hydrops with perforation in one eye is a risk factor for a similar event occurring in the other eye. Initial conservative management with a bandage contact lens should be considered to avoid the risk of surgery. After resolution of hydrops, flattening of the cornea and reduced astigmatism is also a potential benefit.