Fig. 14.1
Schematic demonstration of tear flow obliterated by CCh. Under the normal circumstance, the fornix tear reservoir depicted in dark blue is responsible for delivering tear fluids to the tear meniscus (a) and preocular surface (b) by blinking. In CCh, tear spread and fornix tear reservoir are obliterated by loose and wrinkled conjunctiva (c, green) and prolapse fat (c, arrow) due to degenerated Tenon’s capsule (Taken with permission from Cheng et al. [9])
Case #1
A 49-year-old female presented with ocular irritation, blurry vision, dryness, and tearing in both eyes for 6 years. She had been unsuccessfully treated with various topical concomitant medications including artificial tears, lubricants, conventional steroid, and cyclosporine. Her nasolacrimal drainage system was patent as confirmed by multiple times of probing and irrigation . Upon first office visit, slit lamp examination showed redundant conjunctival tissue interposed between the lid margin and the eye globe and an uneven but high tear meniscus ( Fig. 14.2a ). Her eyelids showed intact closure and blinking. All four puncta were swollen by inflammation and collapsed into a slit-like open appearance (Fig. 14.2b ). Her tarsal and conjunctiva were diffusely injected (Fig. 14.2c , d ).
Fig. 14.2
Case #1. Although CCh is highlighted by conjunctival folds clinically resulting in a discontinuous tear meniscus (a), it can also be accompanied by swollen puncta (b, arrow), tarsal papillary reaction (c), and conjunctival injection most notable at above the lid margin (d), suggesting chronic ocular surface inflammation. FCT showed delayed tear clearance (e). After surgery, this eye recovered smooth, non-inflamed conjunctival surface (f), continuous tear meniscus (g), and non-swollen puncta (h, arrow). Repeat FCT revealed improved tear clearance but same low basal wetting length, i.e., 2 and 3 mm for OD and OS, respectively, for the first two pairs of strips (i). To resolve the remaining symptoms which were due to ATD dry eye, punctal occlusion by plug was performed (j)
Why Did This CCh Patient Complain of Tearing While There was Patent Nasolacrimal Drainage?
The complaint of tearing is most likely resulted from delay tear clearance (DTC). Given that the aqueous tear fluid is cleared through punctum by the eyelid blinking pumping force and stable tear flow, DTC can arise from punctal occlusion , interference with the tear flow, or deficiency of any element in the hydrodynamic reflex. Nevertheless, DTC can also develop in cases of severe ATD to allow the tear meniscus to drop below the level discontiguous to the punctum [13]. Taken together, tear clearance is the convergent point of both hydrodynamic and compositional factors [1]. DTC also occurs when mucosal inflammation and swelling of the ocular surface impose a functional block of tear clearance [14]. One common cause of such mucosal swelling is chronic ocular surface inflammation inflicted by CCh. Conjunctival folds in CCh potentially can also block the punctum [7] besides interrupting the continuity of the tear meniscus [4, 7, 8], interfering with the tear flow from the fornix to the tear meniscus [10] and depleting the fornix tear reservoir [9]. DTC also aggravates ocular surface inflammation, which can then aggravate CCh because DTC also increased inflammatory cytokines in tear levels to upregulate expression of MMPs by CCh fibroblasts [15, 16]. Because DTC is worse during sleep due to the lack of blinking, inflammatory symptoms caused by CCh tend to be worse in the morning upon awakening and are frequently associated with swollen puncta in CCh [8, 14].
How Can One Measure Tear Clearance?
Measurement of tear clearance is indeed a useful clinical test to assess the status of ocular surface defense. The ocular tear volume is traditionally assessed by the Schirmer test , which is known to have a wide range of false positive and negative rates as well as lack of standardization [17–19]. Following application of 5 μL of Fluroress® (Akorn Inc., Abita Springs, LA, USA), which contains anesthetics, fluorescein clearance test (FCT) was performed by applying the Schirmer paper strip for 1 min every 10 min for a total of 30 min, at which time nasal stimulation is performed. Hence, FCT at one setting can determine basal tearing, reflex tearing, and tear clearance [14]. Because the paper strip is bent over the tear meniscus to reach the tear reservoir in the fornix, the measured tear volume conceivably includes both the tear meniscus (the second compartment) and fornix reservoir (the third compartment). The diagnosis of ATD is based on the wetting length of less than 3 mm for the first two sets (10th and 20th min) for measurement of the basal tear volume. The high variability of the Schirmer test [18] is minimized by using FCT, which avoids unquantified anesthetic drop size and reduces the contact of lashes from 5 min for Schirmer I test to 1 min. Tear fluorescence measurements by FCT using the naked eyes (Fig. 14.3) correlate well with fluorophotometry [20]. The intensity of fluorescein dye fades with time under the blue light. Tear clearance is regarded normal if fluorescein becomes invisible to the naked eye after 10 min (i.e., the first pair of strips). In contrast, DTC is defined as fluorescein present on the Schirmer strips at or beyond 20 min (i.e., the second and third pair of strips). FCT can help detect clinical and subclinical DTC which has been overlooked [14].
Fig. 14.3
Representative FCT Examples for different clinical diagnosis. (a) Normal basal tearing, clearance, and reflex tearing. Unilateral (b) and bilateral (c) delayed tear clearance as evidenced by fluorescein present in the right eye (b) or both eyes (c) beyond 20 min
FCT revealed low basal wetting length for 10th and 20th min on both eyes. In addition, the tear clearance that was also delayed as evidenced by the dye could still be detected by the strip taken at the 20 min interval and later (Fig. 14.2e ).
How Can One Treat CCh Patients with DTC?
As DTC aggravates ocular symptoms by precipitating accumulation and prolonging the contact of intrinsic irritative stimuli in the ocular surface, elimination of such intrinsic irritative stimuli/inflammation is the first step [13]. Medicamentosa with accumulation of intrinsic toxic topical medications that contain preservatives is a common overlooked etiology for the eyes with clinically apparent inflammation. It is likely that medicamentosa can precipitate DTC, which in turn can perpetrate medicamentosa in a vicious cycle. Application of topical preservative-free steroid such as methylprednisolone or dexamethasone has shown success in tear clearance improvement by breaking the aforementioned vicious cycle [14].
Under the impression of CCh and ATD with DTC, non-preservative dexamethasone 0.1% was prescribed to control inflammation. Two weeks after treatment, symptoms were partially relieved.
What is the Pathogenesis of CCh?
Although there are conjunctival wrinkles, the underlying pathology of CCh does not reside in the conjunctiva but rather owes to dissolution of the Tenon capsule, which functions as a “carpet pad” to anchor the conjunctiva “carpet” to the underlying sclera “floor.” In CCh, excessive degradation of the extracellular matrix MMPs under inflammatory cytokines results in Tenon’s capsule degeneration [5, 16]. The lack of healthy Tenon’s capsule hence leads to loose and wrinkled conjunctiva, prolapsed fat (Fig. 14.1c), and subconjunctival hemorrhage as the underlying blood vessels can be avulsed during conjunctival movement in the absence of the Tenon capsule.
What Will be the Next Step for Managing Symptomatic CCh After Inflammation Control?
Once ocular inflammations are controlled, restoration of fornix reservoir is the key to achieve effective tear spread for symptomatic CCh patients. Understanding of the underlying pathology of CCh helps formulate surgical procedure aimed at restoration of the fornix tear reservoir . This “reservoir restoration procedure ” (Fig. 14.4) includes the following three key steps: (1) significant rearrangement of conjunctiva by recessing and anchoring it from the limbus to the fornix, (2) thorough removal of degenerated Tenon’s capsule, and (3) replacement of the Tenon and the conjunctival tissue by two separate layers of cryopreserved amniotic membrane (AM) (Bio-Tissue, Miami, FL) to help prevent recurrence and expedite patient’s recovery.
Fig. 14.4
Surgical steps of reservoir restoration procedure. Poor conjunctival adhesion to the sclera from dissolution of the Tenon capsule is noted as evidenced by easy separation of the conjunctiva from the sclera simply by forceps grabbing (a, arrow, b). After using several drops of epinephrine 1/1000 for hemostasis and 2% lidocaine gel for anesthesia, a traction suture made of 7-0 Vicryl is placed 2 mm posterior to the limbus at the 3 and 9 o’clock position and used to rotate the eye upward. An arc-like conjunctival peritomy is created 1–2 mm posterior to the limbus in the area of CCh (c) and extends to remove pinguecula, if present. Rearrangement of conjunctiva by recessing (d, arrow) from the limbus to the fornix. The abnormal Tenon’s capsule (asterisk) that is distributed under the overlying recessed conjunctival epithelial tissue (arrow) and adherent over the bare sclera (e). The abnormal Tenon’s capsule (asterisk) is grabbed and dissected off from the overlying conjunctival epithelial tissue and thoroughly removed by a sharp scissors (f). The recessed conjunctiva (arrow) is lifted up by a forceps to identify the prolapsed fat (star) that is distributed in the fornix (g) and cauterized to create a gap (h) for prevention of fat herniation through fornix. Two separate layers of cryopreserved AM are laid down to replace Tenon (i) and the conjunctival tissue (j) to help prevent recurrence and expedite patient’s recovery. The conjunctival is recessed to anchor at the fornix with 8-0 Vicryl (k, l). Fornix deepening reconstruction with conjunctival recession and AM transplantation restores fornix tear reservoir (m) to help replenish tear meniscus and preocular surface tear film in symptomatic CCh patient (n)
Because of the residual symptoms persisted despite maximal medical treatments, the patient received fornix reconstruction surgery with conjunctival recession and AM transplantation. After surgery, the epithelial defects created by the denuded AM were rapidly epithelialized within 3 weeks. Her eyes recovered smooth, non-inflamed conjunctival surface (Fig. 14.2f ) with restoration of fornix reservoir and tear meniscus (Fig. 14.2g ) and non-swollen puncta (Fig. 14.2h ). However, she noted partial but not complete relief of symptoms including blurry vision, dryness, tearing, and conjunctival redness. Repeat FCT revealed improved tear clearance but same wetting length (Fig. 14.2i ).
Why Not Just Cut Off (Resect) or Cauterize the Redundant Conjunctiva?
As of now, a number of surgical procedures have been advocated to treat CCh such as scleral fixation suture [21], crescent bulbar conjunctival excision with direct closure [7], resection combined with inferior peritomy and radial relaxing incisions [22], excision with AM transplantation [23, 24], cauterization/laser coagulation with or without excision [25, 26], and subconjunctival fibrin sealant followed by excision [27]. Most of these procedures focus on elimination of conjunctival folds close to the tear meniscus—but do not address fornix reconstruction. While these resection procedures may be effective in many cases, reconstruction and deepening of the fornix is best done with conjunctival “recession” not “resection.” In addition, complications such as scar formation and fat prolapse might be attributed to the aforementioned surgical techniques if not performed appropriately.
What is the Clinical Significance if Repeat FCT Shows No Change in the Basal Wetting Length After CCh Surgery?
Changes of basal tear volume after fornix reconstruction help discern genuine or concomitant ATD to clarify logical step in the clinical management algorithm for dry eye [9, 13]. Genuine ATD dry eye is identified by the unchanged basal wetting length despite restoration of fornix tear reservoir after CCh surgery. If there are still residual non-resolving dry eye manifestations, treatment sho uld be directed to compositional deficiency dry eye [13]. In this regard, the conventional treatment for ATD dry eye can be managed more effectively by punctal occlusion , which remains the mainstay of managing ATD dry eye when the application of artificial tears reaches a maximum certain daily frequency. Because punctal occlusion invariably delays tear drainage/clearance, it can prolong the beneficial effect of topical artificial tears for ATD but potentially cause toxicity to the ocular surface as a result of prolonged retention of preservative-containing artificial tears. Hence, it is advised that non-preserved tear substitutes are preferred, because CCh can aggravate DTC, which is why surgical correction of CCh is performed before punctal occlusion is contemplated.
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