Hearing Loss Associated with Ocular Pseudoexfoliation Syndrome

Abstract

Objectives: To investigate the type and degree of hearing loss in a group of patients with ocular pseudoexfoliation.

Methods:  Two groups of patients were included prospectively in the present study. The study group consisted of 60 patients of both genders, aged between 55 and 80 years (mean age 67.8 years) who were identified to have pseudoexfoliation in one or both eyes on routine ophthalmic clinical examination at Princess Haya Bent Al-Hussein Military Hospital in Aqaba.  The control group consisted of 30 healthy individuals matched for age and gender (mean age 56.9 years). All participants underwent full ophthalmological and audiological assessments.

Results: Normal hearing threshold levels ranging between 10-25 decibels were found in 12 (20%) patients. Moderate sensori-neural hearing loss ranging between 50-70 decibels was found in 15 (25%) patients, high frequency sensori-neural hearing loss in the frequency range above 3kilohertz was found in 10 (16.7%) patients, and severe sensori-neural hearing loss ranging between 70-95 decibels hearing level was found in 23 (38.3%) patients.

Conclusion:  There is evidence of significant association between ocular pseudoexfoliation and sensori-neural hearing loss.

Key words: Hearing loss, Sensori-neural, Pseudoexfoliation

JRMS December 2010; 17(4): 15-18

Introduction

Pseudoexfoliation (PEX) syndrome has been described as a specific type of stress-induced elastosis, elastic microfibrillopathy, associated with the excessive production and abnormal aggregation of elastic microfibril components which may be promoted by the deficiency of clusterin as a highly efficient extracellular chaperone.⁽¹⁾

Ocular PEX syndrome is characterized by deposits of fibrillar extracellular material on anterior segment structures of the eye including the zonules, anterior capsule and trabecular meshwork, and may be associated with raised intraocular pressure in up to 50% of affected eyes.⁽²⁾

Originally, PEX syndrome was thought to be limited to the anterior segment of the eye, however, recent studies have demonstrated that pseudoexfoliation material is a common age related fibrillopathy of unknown cause and is widely distributed throughout the body, including blood vessels, heart, and lung. These pseudoexfoliation fibers are consistently associated with fibroblasts, collagen and elastic fibers.⁽³⁾

Patients with PEX syndrome and glaucoma are at increased risk of carotid artery stiffness and decrease of baroreflex sensitivity.⁽⁴⁾

Ocular pseudoexfoliation-like deposits have been also found in various other organs and tissues such as liver, kidney, meninges and skin.  The correlation between glaucoma and hearing loss has been previously studied but with the exception of normal tension glaucoma and some congenital syndromes, no strong evidence is available for such an association. Clinical impression described by investigators considering the structural characteristics of hearing organs and the possible adverse effect of abnormal deposits and/or vascular abnormalities on these organs would not be surprising.⁽⁵⁾

The inner ear is a complex organ where sound waves are translated into bioelectrical energy and afferent electrical nerve impulses. Embryologically, the anterior segment structure of the eye as well as the tectorial and basilar membranes in the inner ear are all derived from neural ectoderm. Fibrils of PEX material that accumulate on lens, pupillary margin, and other anterior segment structures can also accumulate on the tectorial and basilar membranes as well as stria vascularis in the inner ear.⁽⁶⁾

Hearing loss associated with PEX has been shown in several studies at some tested frequencies, but no studies have been carried out to determine the type and degree of hearing loss associated with PEX at all audiometric tested frequencies. Cahil et al. assessed the relationship between PEX and sensori-neural hearing loss in 69 patients with pseudoexfoliation at tested frequencies:  1, 2, and 3 kHz. They found that a large proportion of patients with pseudoexfoliation have sensori-neural hearing loss.⁽²⁾   Similarly, Shaban and Asfour investigated the relationship between ocular PEX and sensori-neural hearing loss in 41 patients with PEX at three pure tone tested frequencies; they found that the majority of patients with ocular PEX had sensori-neural hearing loss.⁽⁶⁾

Yazdin et al. compared hearing threshold levels of 83 subjects with ocular PEX and compared with 83 age and gender matched controls without PEX at sound frequencies important for speech comprehension (1,2, and 3 kHz). They concluded that hearing threshold levels at frequencies that are important for speech comprehension are significantly worse in individuals with ocular PEX than in matched controls.⁽⁵⁾

Turacli et al. investigated the possible relationship between PEX and sensori-neural hearing loss in a group of 51 patients with PEX and 22 controls without PEX.  They found that sensori-neural hearing loss was detected in the majority of PEX patients.⁽⁷⁾  Aydogan et al. tested 75 subjects with PEX with a well matched control group, performing pure tone audiometry at 250, 500, 1000, 2000, 4000, and 8000 Hz. They found that mean thresholds at speech frequencies and mean absolute hearing thresholds at 2, 4, and 8 kHz were higher in PEX patients than controls; however, absolute hearing thresholds at 250, 500, and 1000 Hz individually did not differ significantly between cases and controls.⁽⁸⁾

The purpose of the present study is to determine the type and the degree of hearing loss at all tested audiometric frequencies and to determine which part of basilar membrane is affected.

Methods

Two groups of patients were included prospectively in the present study. A group of 60 patients of both genders, aged between 55 -80 years (mean age 67.8 years) who were identified as having PEX in one or both eyes in routine ophthalmic clinical examination at Princess Haya Bent Al-Hussein Military Hospital at Aqaba, were included in the study group. The control group consisted of 30 healthy age and gender matched individuals without PEX (mean age 56.9 years).

Full medical history was taken from all patients, including current or previous medical and surgical treatment for eyes and any ear, nose and throat diseases.  Exclusion criteria were history of previous ear surgery, history of tympanic membrane perforation, history of head trauma, history of noise exposure, or working in a noisy environment, or repeated exposure to gun fire, use of ototoxic drugs, and concurrent upper respiratory tract infection at time of examination. Each patient underwent a full ocular examination including Snellen visual acuity test, slit lamp biomicroscopy, gonioscopy, applanation tonometry, and dilated fundoscopy. After that, all patients were referred to the Ear-Nose-Throat (ENT) unit for audiological assessment. Assessment was as follows:

1.    Otoscopic examination: otoscopic investigation of the external and middle ear was carried out on each ear of the participants of both groups by ENT doctors to evaluate any disorders of the external and middle ear.